Other: Release Bridge Iron v1.7.0

Add patched libqcocoa based on Qt 5.13.0

.golangci.yml

@@ -1,3 +1,4 @@
+---
 run:
   timeout: 10m
   build-tags:
@@ -8,9 +9,11 @@ run:
 issues:
   exclude-use-default: false
   exclude:
-     - Using the variable on range scope `tt` in function literal
-     - should have comment (\([^)]+\) )?or be unexported # For now we are missing a lot of comments.
-     - at least one file in a package should have a package comment # For now we are missing a lot of comments.
+    - Using the variable on range scope `tt` in function literal
+    # For now we are missing a lot of comments.
+    - should have comment (\([^)]+\) )?or be unexported
+    # For now we are missing a lot of comments.
+    - at least one file in a package should have a package comment
 
   exclude-rules:
     - path: _test\.go
@@ -30,7 +33,7 @@ linters-settings:
 linters:
   # setting disable-all will make only explicitly enabled linters run
   disable-all: true
-  
+
   enable:
     - deadcode          # Finds unused code [fast: true, auto-fix: false]
     - errcheck          # Errcheck is a program for checking for unchecked errors in go programs. These unchecked errors can be critical bugs in some cases [fast: true, auto-fix: false]
@@ -49,7 +52,6 @@ linters:
     - funlen            # Tool for detection of long functions [fast: true, auto-fix: false]
     - gochecknoglobals  # Checks that no globals are present in Go code [fast: true, auto-fix: false]
     - gochecknoinits    # Checks that no init functions are present in Go code [fast: true, auto-fix: false]
-    #- gocognit          # Computes and checks the cognitive complexity of functions [fast: true, auto-fix: false]
     - goconst           # Finds repeated strings that could be replaced by a constant [fast: true, auto-fix: false]
     - gocritic          # The most opinionated Go source code linter [fast: true, auto-fix: false]
     - gocyclo           # Computes and checks the cyclomatic complexity of functions [fast: true, auto-fix: false]
@@ -58,15 +60,52 @@ linters:
     - goimports         # Goimports does everything that gofmt does. Additionally it checks unused imports [fast: true, auto-fix: true]
     - golint            # Golint differs from gofmt. Gofmt reformats Go source code, whereas golint prints out style mistakes [fast: true, auto-fix: false]
     - gosec             # Inspects source code for security problems [fast: true, auto-fix: false]
-    - interfacer        # Linter that suggests narrower interface types [fast: true, auto-fix: false]
-    - maligned          # Tool to detect Go structs that would take less memory if their fields were sorted [fast: true, auto-fix: false]
     - misspell          # Finds commonly misspelled English words in comments [fast: true, auto-fix: true]
     - nakedret          # Finds naked returns in functions greater than a specified function length [fast: true, auto-fix: false]
     - prealloc          # Finds slice declarations that could potentially be preallocated [fast: true, auto-fix: false]
-    - scopelint         # Scopelint checks for unpinned variables in go programs [fast: true, auto-fix: false]
     - stylecheck        # Stylecheck is a replacement for golint [fast: true, auto-fix: false]
     - unconvert         # Remove unnecessary type conversions [fast: true, auto-fix: false]
     - unparam           # Reports unused function parameters [fast: true, auto-fix: false]
     - whitespace        # Tool for detection of leading and trailing whitespace [fast: true, auto-fix: true]
-    #- wsl               # Whitespace Linter - Forces you to use empty lines! [fast: true, auto-fix: false]
-    #- lll               # Reports long lines [fast: true, auto-fix: false]
+    - asciicheck        # Simple linter to check that your code does not contain non-ASCII identifiers [fast: true, auto-fix: false]
+    - durationcheck     # check for two durations multiplied together [fast: false, auto-fix: false]
+    - exhaustive        # check exhaustiveness of enum switch statements [fast: false, auto-fix: false]
+    - exportloopref     # checks for pointers to enclosing loop variables [fast: false, auto-fix: false]
+    - forcetypeassert   # finds forced type assertions [fast: true, auto-fix: false]
+    - godot             # Check if comments end in a period [fast: true, auto-fix: true]
+    - goheader          # Checks is file header matches to pattern [fast: true, auto-fix: false]
+    - gomodguard        # Allow and block list linter for direct Go module dependencies. This is different from depguard where there are different block types for example version constraints and module recommendations. [fast: true, auto-fix: false]
+    - goprintffuncname  # Checks that printf-like functions are named with `f` at the end [fast: true, auto-fix: false]
+    - importas          # Enforces consistent import aliases [fast: false, auto-fix: false]
+    - makezero          # Finds slice declarations with non-zero initial length [fast: false, auto-fix: false]
+    - nilerr            # Finds the code that returns nil even if it checks that the error is not nil. [fast: false, auto-fix: false]
+    - predeclared       # find code that shadows one of Go's predeclared identifiers [fast: true, auto-fix: false]
+    - revive            # Fast, configurable, extensible, flexible, and beautiful linter for Go. Drop-in replacement of golint. [fast: false, auto-fix: false]
+    - rowserrcheck      # checks whether Err of rows is checked successfully [fast: false, auto-fix: false]
+    - sqlclosecheck     # Checks that sql.Rows and sql.Stmt are closed. [fast: false, auto-fix: false]
+    - tparallel         # tparallel detects inappropriate usage of t.Parallel() method in your Go test codes [fast: false, auto-fix: false]
+    - wastedassign      # wastedassign finds wasted assignment statements. [fast: false, auto-fix: false]
+    # - wsl               # Whitespace Linter - Forces you to use empty lines! [fast: true, auto-fix: false]
+    # - lll               # Reports long lines [fast: true, auto-fix: false]
+    # Consider to include:
+    # - gocognit          # Computes and checks the cognitive complexity of functions [fast: true, auto-fix: false]
+    # - cyclop            # checks function and package cyclomatic complexity [fast: false, auto-fix: false]
+    # - errorlint         # go-errorlint is a source code linter for Go software that can be used to find code that will cause problems with the error wrapping scheme introduced in Go 1.13. [fast: false, auto-fix: false]
+    # - exhaustivestruct  # Checks if all struct's fields are initialized [fast: false, auto-fix: false]
+    # - forbidigo         # Forbids identifiers [fast: true, auto-fix: false]
+    # - gci               # Gci control golang package import order and make it always deterministic. [fast: true, auto-fix: true]
+    # - gocognit          # Computes and checks the cognitive complexity of functions [fast: true, auto-fix: false]
+    # - goerr113          # Golang linter to check the errors handling expressions [fast: false, auto-fix: false]
+    # - gofumpt           # Gofumpt checks whether code was gofumpt-ed. [fast: true, auto-fix: true]
+    # - gomnd             # An analyzer to detect magic numbers. [fast: true, auto-fix: false]
+    # - gomoddirectives   # Manage the use of 'replace', 'retract', and 'excludes' directives in go.mod. [fast: true, auto-fix: false]
+    # - ifshort           # Checks that your code uses short syntax for if-statements whenever possible [fast: true, auto-fix: false]
+    # - nestif            # Reports deeply nested if statements [fast: true, auto-fix: false]
+    # - nlreturn          # nlreturn checks for a new line before return and branch statements to increase code clarity [fast: true, auto-fix: false]
+    # - noctx             # noctx finds sending http request without context.Context [fast: false, auto-fix: false]
+    # - nolintlint        # Reports ill-formed or insufficient nolint directives [fast: true, auto-fix: false]
+    # - paralleltest      # paralleltest detects missing usage of t.Parallel() method in your Go test [fast: true, auto-fix: false]
+    # - testpackage       # linter that makes you use a separate _test package [fast: true, auto-fix: false]
+    # - thelper           # thelper detects golang test helpers without t.Helper() call and checks the consistency of test helpers [fast: false, auto-fix: false]
+    # - wrapcheck         # Checks that errors returned from external packages are wrapped [fast: false, auto-fix: false]
+

Changelog.md

@@ -2,6 +2,89 @@
 
 Changelog [format](http://keepachangelog.com/en/1.0.0/)
 
+## [Bridge 1.7.0] Iron
+
+### Added
+* GODT-213 New message builder:
+    * Preserve Content-Type for undecryptable message body.
+    * Use application/octet-stream for encrypted parts.
+    * Force no transfer encoding for embedded message/rfc822 parts.
+    * Remove dead code GetRelatedHeader/GetRelatedBoundary.
+    * Correctly expect text/plain in custom message text parts.
+    * Force text/plain for custom message text part.
+    * Complex external encrypted tests (multipart/alternative, message/rfc822 attachment).
+
+### Fixed
+* GODT-1136 DB Cache header from builder and test.
+* GODT-1113 Fix tray icon size on macOS Big Sur.
+* GODT-947 Force colors in logs.
+
+
+## [Bridge 1.6.9] HZM
+
+### Fixed
+* GODT-1121 'Keep the application up to date' switches off after restarting Bridge.
+
+
+## [Bridge 1.6.8] HZM
+
+### Fixed
+* GODT-1120 Use Info level in internal/app logs.
+
+
+## [IE 1.3.3] Farg
+
+### Fixed
+* GODT-1120 Use Info level in internal/app logs.
+
+
+## [Bridge 1.6.7] HZM
+
+### Added
+* GODT-1111 Add correct metadata to Windows executables.
+* GODT-1112 Add application to Windows Firewall exclusion list on install.
+* GODT-1077 Track how many times message is built to help understand re-syncs.
+
+### Changed
+* GODT-247 Revise all storage locations (cache, config, local etc).
+
+### Fixed
+* GODT-948 Parser does not handle embedding of Content-Type: message/rfc822.
+* GODT-1079 Correct 9001 error handling on login.
+
+### Security
+* GODT-1105 Dylib Hijacking security fix.
+
+
+## [IE 1.3.2] Farg
+
+### Added
+* GODT-1111 Add correct metadata to Windows executables.
+* GODT-1112 Add application to Windows Firewall exclusion list on install.
+
+### Changed
+* GODT-247 Revise all storage locations (cache, config, local etc).
+
+### Fixed
+* GODT-1079 Correct 9001 error handling on login.
+
+### Security
+* GODT-1105 Dylib Hijacking security fix.
+
+
+## [IE 1.3.1] Farg
+
+### Changed
+* GODT-1047 No silent updates for Import-Export app.
+* GODT-247 Cache and update files moved from user's cache to config.
+
+### Fixed
+* Other: include latest go.mod/go.sum changes.
+* GODT-803 Fix import to wrong target address.
+* GODT-948 Embedded messages.
+* GODT-1043 Fix showing long login error in GUI dialog.
+
+
 ## [Bridge 1.6.6] HZM
 
 ### Added

Makefile

@@ -10,8 +10,8 @@ TARGET_OS?=${GOOS}
 .PHONY: build build-ie build-nogui build-ie-nogui build-launcher build-launcher-ie  versioner hasher
 
 # Keep version hardcoded so app build works also without Git repository.
-BRIDGE_APP_VERSION?=1.6.6+git
-IE_APP_VERSION?=1.3.0+git
+BRIDGE_APP_VERSION?=1.7.0+git
+IE_APP_VERSION?=1.3.3+git
 APP_VERSION:=${BRIDGE_APP_VERSION}
 SRC_ICO:=logo.ico
 SRC_ICNS:=Bridge.icns
@@ -19,6 +19,7 @@ SRC_SVG:=logo.svg
 TGT_ICNS:=Bridge.icns
 EXE_NAME:=proton-bridge
 CONFIGNAME:=bridge
+WINDRES_DEFINE:=BUILD_BRIDGE
 ifeq "${TARGET_CMD}" "Import-Export"
     APP_VERSION:=${IE_APP_VERSION}
     SRC_ICO:=ie.ico
@@ -27,6 +28,7 @@ ifeq "${TARGET_CMD}" "Import-Export"
     TGT_ICNS:=ImportExport.icns
     EXE_NAME:=proton-ie
     CONFIGNAME:=importExport
+	WINDRES_DEFINE:=BUILD_IE
 endif
 REVISION:=$(shell git rev-parse --short=10 HEAD)
 BUILD_TIME:=$(shell date +%FT%T%z)
@@ -56,7 +58,7 @@ EXE_QT:=${DIRNAME}
 ifeq "${TARGET_OS}" "windows"
     EXE:=${EXE}.exe
     EXE_QT:=${EXE_QT}.exe
-    ICO_FILES:=${SRC_ICO} icon.rc icon_windows.syso
+    RESOURCE_FILE:=resource.syso
 endif
 ifeq "${TARGET_OS}" "darwin"
     DARWINAPP_CONTENTS:=${DEPLOY_DIR}/darwin/${EXE}.app/Contents
@@ -89,8 +91,14 @@ build-nogui: gofiles
 build-ie-nogui:
 	TARGET_CMD=Import-Export $(MAKE) build-nogui
 
-build-launcher:
-	go build ${BUILD_FLAGS_LAUNCHER} -o launcher-${APP} cmd/launcher/main.go
+ifeq "${GOOS}" "windows"
+  	PRERESOURCECMD:=cp ./resource.syso ./cmd/launcher/resource.syso
+	POSTRESOURCECMD:=rm -f ./cmd/launcher/resource.syso
+endif
+build-launcher: ${RESOURCE_FILE}
+	${PRERESOURCECMD}
+	go build ${BUILD_FLAGS_LAUNCHER} -o launcher-${EXE} ./cmd/launcher/
+	${POSTRESOURCECMD}
 
 build-launcher-ie:
 	TARGET_CMD=Import-Export $(MAKE) build-launcher
@@ -134,7 +142,7 @@ ifneq "${GOOS}" "${TARGET_OS}"
   endif
 endif
 
-${EXE_TARGET}: check-has-go gofiles ${ICO_FILES} ${VENDOR_TARGET}
+${EXE_TARGET}: check-has-go gofiles ${RESOURCE_FILE} ${VENDOR_TARGET}
 	rm -rf deploy ${TARGET_OS} ${DEPLOY_DIR}
 	cp cmd/${TARGET_CMD}/main.go .
 	qtdeploy ${BUILD_FLAGS_GUI} ${QT_BUILD_TARGET}
@@ -142,13 +150,12 @@ ${EXE_TARGET}: check-has-go gofiles ${ICO_FILES} ${VENDOR_TARGET}
 	if [ "${EXE_QT_TARGET}" != "${EXE_TARGET}" ]; then mv ${EXE_QT_TARGET} ${EXE_TARGET}; fi
 	rm -rf ${TARGET_OS} main.go
 
-logo.ico ie.ico: ./internal/frontend/share/icons/${SRC_ICO}
-	cp $^ $@
-icon.rc: ./internal/frontend/share/icon.rc
-	cp $^ .
-icon_windows.syso: icon.rc logo.ico
-	windres --target=pe-x86-64 -o $@ $<
 
+WINDRES_YEAR:=$(shell date +%Y)
+APP_VERSION_COMMA:=$(shell echo "${APP_VERSION}" | sed -e 's/[^0-9,.]*//g' -e 's/\./,/g')
+resource.syso: ./internal/frontend/share/info.rc ./internal/frontend/share/icons/${SRC_ICO} .FORCE
+	rm -f ./*.syso
+	windres --target=pe-x86-64 -I ./internal/frontend/share/icons/ -D ${WINDRES_DEFINE} -D ICO_FILE=${SRC_ICO} -D EXE_NAME="${EXE_NAME}" -D FILE_VERSION="${APP_VERSION}" -D ORIGINAL_FILE_NAME="${EXE}" -D PRODUCT_VERSION="${APP_VERSION}" -D FILE_VERSION_COMMA=${APP_VERSION_COMMA} -D YEAR=${WINDRES_YEAR} -o $@ $<
 
 ## Rules for therecipe/qt
 .PHONY: prepare-vendor update-vendor update-qt-docs
@@ -158,6 +165,7 @@ THERECIPE_ENV:=github.com/therecipe/env_${TARGET_OS}_amd64_513
 # therecipe/env in order to download it only once
 vendor-cache/${THERECIPE_ENV}:
 	git clone https://${THERECIPE_ENV}.git vendor-cache/${THERECIPE_ENV}
+	if [ "${TARGET_OS}" == "darwin" ]; then cp -f "./utils/QTBUG-88600/libqcocoa.dylib" "./vendor-cache/${THERECIPE_ENV}/5.13.0/clang_64/plugins/platforms/"; fi;
 
 # The command used to make symlinks is different on windows.
 # So if the GOOS is windows and we aren't crossbuilding (in which case the host os would still be *nix)
@@ -181,7 +189,7 @@ update-qt-docs:
 
 ## Dev dependencies
 .PHONY: install-devel-tools install-linter install-go-mod-outdated install-git-hooks
-LINTVER:="v1.29.0"
+LINTVER:="v1.39.0"
 LINTSRC:="https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh"
 
 install-dev-dependencies: install-devel-tools install-linter install-go-mod-outdated
@@ -250,6 +258,7 @@ mocks:
 	mockgen --package mocks github.com/ProtonMail/proton-bridge/internal/transfer PanicHandler,ClientManager,IMAPClientProvider > internal/transfer/mocks/mocks.go
 	mockgen --package mocks github.com/ProtonMail/proton-bridge/internal/store PanicHandler,ClientManager,BridgeUser,ChangeNotifier > internal/store/mocks/mocks.go
 	mockgen --package mocks github.com/ProtonMail/proton-bridge/pkg/listener Listener > internal/store/mocks/utils_mocks.go
+	mockgen --package mocks github.com/ProtonMail/proton-bridge/pkg/message Fetcher > pkg/message/mocks/mocks.go
 	mockgen --package mocks github.com/ProtonMail/proton-bridge/pkg/pmapi Client > pkg/pmapi/mocks/mocks.go
 
 lint: gofiles lint-golang lint-license lint-changelog
@@ -294,6 +303,7 @@ LOG?=debug
 LOG_IMAP?=client # client/server/all, or empty to turn it off
 LOG_SMTP?=--log-smtp # empty to turn it off
 RUN_FLAGS?=-m -l=${LOG} --log-imap=${LOG_IMAP} ${LOG_SMTP}
+RUN_FLAGS_IE?=-m -l=${LOG}
 
 run: run-nogui-cli
 
@@ -316,11 +326,11 @@ run-ie-qml-preview:
 	$(MAKE) -C internal/frontend/qt-ie -f Makefile.local qmlpreview
 
 run-ie:
-	TARGET_CMD=Import-Export $(MAKE) run
+	TARGET_CMD=Import-Export RUN_FLAGS="${RUN_FLAGS_IE}" $(MAKE) run
 run-ie-qt:
-	TARGET_CMD=Import-Export $(MAKE) run-qt
+	TARGET_CMD=Import-Export RUN_FLAGS="${RUN_FLAGS_IE}" $(MAKE) run-qt
 run-ie-nogui:
-	TARGET_CMD=Import-Export $(MAKE) run-nogui
+	TARGET_CMD=Import-Export RUN_FLAGS="${RUN_FLAGS_IE}" $(MAKE) run-nogui
 
 clean-frontend-qt:
 	$(MAKE) -C internal/frontend/qt -f Makefile.local clean
@@ -337,7 +347,7 @@ clean: clean-vendor
 	rm -rf cmd/Desktop-Bridge/deploy
 	rm -rf cmd/Import-Export/deploy
 	rm -f build last.log mem.pprof main.go
-	rm -rf logo.ico icon.rc icon_windows.syso internal/frontend/qt/icon_windows.syso
+	rm -f resource.syso
 	rm -f release-notes/bridge.html
 	rm -f release-notes/import-export.html
 
@@ -345,3 +355,5 @@ clean: clean-vendor
 generate:
 	go generate ./...
 	$(MAKE) add-license
+
+.FORCE:

go.mod

@@ -54,7 +54,6 @@ require (
 	github.com/nsf/jsondiff v0.0.0-20200515183724-f29ed568f4ce
 	github.com/olekukonko/tablewriter v0.0.4 // indirect
 	github.com/pkg/errors v0.9.1
-	github.com/pkg/math v0.0.0-20141027224758-f2ed9e40e245
 	github.com/sirupsen/logrus v1.7.0
 	github.com/skratchdot/open-golang v0.0.0-20200116055534-eef842397966
 	github.com/ssor/bom v0.0.0-20170718123548-6386211fdfcf // indirect

go.sum

@@ -223,8 +223,6 @@ github.com/pingcap/errors v0.11.4/go.mod h1:Oi8TUi2kEtXXLMJk9l1cGmz20kV3TaQ0usTw
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pkg/math v0.0.0-20141027224758-f2ed9e40e245 h1:gk/AF9SGRj+RafNCoDcS3RRscb8S4BVbvqODOgWA7/8=
-github.com/pkg/math v0.0.0-20141027224758-f2ed9e40e245/go.mod h1:2dhPPj2Li3DXrSY2U2ADdZy2B7sjQsT57lqENx1+FSE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday v1.5.2 h1:HyvC0ARfnZBqnXwABFeSZHpKvJHJJfPz81GNueLj0oo=

internal/app/base/base.go

@@ -69,7 +69,7 @@ const (
 	flagMemProfileShort = "m"
 	flagLogLevel        = "log-level"
 	flagLogLevelShort   = "l"
-	// FlagCLI indicate to start with command line interface
+	// FlagCLI indicate to start with command line interface.
 	FlagCLI      = "cli"
 	flagCLIShort = "c"
 	flagRestart  = "restart"

internal/app/base/migration.go

@@ -29,10 +29,12 @@ import (
 // migrateFiles migrates files from their old (pre-refactor) locations to their new locations.
 // We can remove this eventually.
 //
-// | entity |               old location                |            new location                |
-// |--------|-------------------------------------------|----------------------------------------|
-// | prefs  | ~/.cache/protonmail/<app>/c11/prefs.json  | ~/.config/protonmail/<app>/prefs.json  |
-// | c11    | ~/.cache/protonmail/<app>/c11             | ~/.cache/protonmail/<app>/cache/c11    |
+// | entity    |               old location                |            new location                |
+// |-----------|-------------------------------------------|----------------------------------------|
+// | prefs     | ~/.cache/protonmail/<app>/c11/prefs.json  | ~/.config/protonmail/<app>/prefs.json  |
+// | c11 1.5.x | ~/.cache/protonmail/<app>/c11             | ~/.cache/protonmail/<app>/cache/c11    |
+// | c11 1.6.x | ~/.cache/protonmail/<app>/cache/c11       | ~/.config/protonmail/<app>/cache/c11   |
+// | updates   | ~/.cache/protonmail/<app>/updates         | ~/.config/protonmail/<app>/updates     |.
 func migrateFiles(configName string) error {
 	locationsProvider, err := locations.NewDefaultProvider(filepath.Join(constants.VendorName, configName))
 	if err != nil {
@@ -41,43 +43,89 @@ func migrateFiles(configName string) error {
 
 	locations := locations.New(locationsProvider, configName)
 	userCacheDir := locationsProvider.UserCache()
+
+	if err := migratePrefsFrom15x(locations, userCacheDir); err != nil {
+		return err
+	}
+	if err := migrateCacheFromBoth15xAnd16x(locations, userCacheDir); err != nil {
+		return err
+	}
+	if err := migrateUpdatesFrom16x(configName, locations); err != nil { //nolint[revive] It is more clear to structure this way
+		return err
+	}
+	return nil
+}
+
+func migratePrefsFrom15x(locations *locations.Locations, userCacheDir string) error {
 	newSettingsDir, err := locations.ProvideSettingsPath()
 	if err != nil {
 		return err
 	}
 
-	if err := moveIfExists(
+	return moveIfExists(
 		filepath.Join(userCacheDir, "c11", "prefs.json"),
 		filepath.Join(newSettingsDir, "prefs.json"),
-	); err != nil {
-		return err
-	}
+	)
+}
 
-	newCacheDir, err := locations.ProvideCachePath()
+func migrateCacheFromBoth15xAnd16x(locations *locations.Locations, userCacheDir string) error {
+	olderCacheDir := userCacheDir
+	newerCacheDir := locations.GetOldCachePath()
+	latestCacheDir, err := locations.ProvideCachePath()
 	if err != nil {
 		return err
 	}
 
+	// Migration for versions before 1.6.x.
 	if err := moveIfExists(
-		filepath.Join(userCacheDir, "c11"),
-		filepath.Join(newCacheDir, "c11"),
+		filepath.Join(olderCacheDir, "c11"),
+		filepath.Join(latestCacheDir, "c11"),
 	); err != nil {
 		return err
 	}
 
-	return nil
+	// Migration for versions 1.6.x.
+	return moveIfExists(
+		filepath.Join(newerCacheDir, "c11"),
+		filepath.Join(latestCacheDir, "c11"),
+	)
+}
+
+func migrateUpdatesFrom16x(configName string, locations *locations.Locations) error {
+	// In order to properly update Bridge 1.6.X and higher we need to
+	// change the launcher first. Since this is not part of automatic
+	// updates the migration must wait until manual update. Until that
+	// we need to keep old path.
+	if configName == "bridge" {
+		return nil
+	}
+
+	oldUpdatesPath := locations.GetOldUpdatesPath()
+	// Do not use ProvideUpdatesPath, that creates dir right away.
+	newUpdatesPath := locations.GetUpdatesPath()
+
+	return moveIfExists(oldUpdatesPath, newUpdatesPath)
 }
 
 func moveIfExists(source, destination string) error {
+	l := logrus.WithField("source", source).WithField("destination", destination)
+
 	if _, err := os.Stat(source); os.IsNotExist(err) {
-		logrus.WithField("source", source).WithField("destination", destination).Debug("No need to migrate file")
+		l.Info("No need to migrate file, source doesn't exist")
 		return nil
 	}
 
 	if _, err := os.Stat(destination); !os.IsNotExist(err) {
-		logrus.WithField("source", source).WithField("destination", destination).Debug("No need to migrate file")
+		// Once migrated, files should not stay in source anymore. Therefore
+		// if some files are still in source location but target already exist,
+		// it's suspicious. Could happen by installing new version, then the
+		// old one because of some reason, and then the new one again.
+		// Good to see as warning because it could be a reason why Bridge is
+		// behaving weirdly, like wrong configuration, or db re-sync and so on.
+		l.Warn("No need to migrate file, target already exists")
 		return nil
 	}
 
+	l.Info("Migrating files")
 	return os.Rename(source, destination)
 }

internal/app/bridge/bridge.go

@@ -189,9 +189,10 @@ func generateTLSCerts(b *base.Base) error {
 }
 
 func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool) {
+	log := logrus.WithField("pkg", "app/bridge")
 	version, err := u.Check()
 	if err != nil {
-		logrus.WithError(err).Error("An error occurred while checking for updates")
+		log.WithError(err).Error("An error occurred while checking for updates")
 		return
 	}
 
@@ -201,11 +202,11 @@ func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool)
 	f.SetVersion(version)
 
 	if !u.IsUpdateApplicable(version) {
-		logrus.Debug("No need to update")
+		log.Info("No need to update")
 		return
 	}
 
-	logrus.WithField("version", version.Version).Info("An update is available")
+	log.WithField("version", version.Version).Info("An update is available")
 
 	if !autoUpdate {
 		f.NotifyManualUpdate(version, u.CanInstall(version))
@@ -213,16 +214,16 @@ func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool)
 	}
 
 	if !u.CanInstall(version) {
-		logrus.Info("A manual update is required")
+		log.Info("A manual update is required")
 		f.NotifySilentUpdateError(updater.ErrManualUpdateRequired)
 		return
 	}
 
 	if err := u.InstallUpdate(version); err != nil {
 		if errors.Cause(err) == updater.ErrDownloadVerify {
-			logrus.WithError(err).Warning("Skipping update installation due to temporary error")
+			log.WithError(err).Warning("Skipping update installation due to temporary error")
 		} else {
-			logrus.WithError(err).Error("The update couldn't be installed")
+			log.WithError(err).Error("The update couldn't be installed")
 			f.NotifySilentUpdateError(err)
 		}
 

internal/app/ie/ie.go

@@ -28,8 +28,6 @@ import (
 	"github.com/ProtonMail/proton-bridge/internal/frontend"
 	"github.com/ProtonMail/proton-bridge/internal/frontend/types"
 	"github.com/ProtonMail/proton-bridge/internal/importexport"
-	"github.com/ProtonMail/proton-bridge/internal/updater"
-	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
@@ -88,10 +86,11 @@ func run(b *base.Base, c *cli.Context) error {
 	return f.Loop()
 }
 
-func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool) {
+func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool) { //nolint[unparam]
+	log := logrus.WithField("pkg", "app/ie")
 	version, err := u.Check()
 	if err != nil {
-		logrus.WithError(err).Error("An error occurred while checking for updates")
+		log.WithError(err).Error("An error occurred while checking for updates")
 		return
 	}
 
@@ -101,33 +100,11 @@ func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool)
 	f.SetVersion(version)
 
 	if !u.IsUpdateApplicable(version) {
-		logrus.Debug("No need to update")
+		log.Info("No need to update")
 		return
 	}
 
-	logrus.WithField("version", version.Version).Info("An update is available")
+	log.WithField("version", version.Version).Info("An update is available")
 
-	if !autoUpdate {
-		f.NotifyManualUpdate(version, u.CanInstall(version))
-		return
-	}
-
-	if !u.CanInstall(version) {
-		logrus.Info("A manual update is required")
-		f.NotifySilentUpdateError(updater.ErrManualUpdateRequired)
-		return
-	}
-
-	if err := u.InstallUpdate(version); err != nil {
-		if errors.Cause(err) == updater.ErrDownloadVerify {
-			logrus.WithError(err).Warning("Skipping update installation due to temporary error")
-		} else {
-			logrus.WithError(err).Error("The update couldn't be installed")
-			f.NotifySilentUpdateError(err)
-		}
-
-		return
-	}
-
-	f.NotifySilentUpdateInstalled()
+	f.NotifyManualUpdate(version, u.CanInstall(version))
 }

internal/config/settings/settings.go

@@ -78,7 +78,7 @@ func (s *Settings) setDefaultValues() {
 	s.setDefault(ReportOutgoingNoEncKey, "false")
 	s.setDefault(LastVersionKey, "")
 	s.setDefault(UpdateChannelKey, "")
-	s.setDefault(RolloutKey, fmt.Sprintf("%v", rand.Float64()))
+	s.setDefault(RolloutKey, fmt.Sprintf("%v", rand.Float64())) //nolint[gosec] G404 It is OK to use weak random number generator here
 	s.setDefault(PreferredKeychainKey, "")
 
 	s.setDefault(APIPortKey, DefaultAPIPort)

internal/config/tls/tls.go

@@ -122,11 +122,7 @@ func (t *TLS) GenerateCerts(template *x509.Certificate) error {
 	}
 	defer keyOut.Close() // nolint[errcheck]
 
-	if err := pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)}); err != nil {
-		return err
-	}
-
-	return nil
+	return pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)})
 }
 
 // GetConfig tries to load TLS config or generate new one which is then returned.
@@ -148,6 +144,7 @@ func (t *TLS) GetConfig() (*tls.Config, error) {
 	caCertPool := x509.NewCertPool()
 	caCertPool.AddCert(c.Leaf)
 
+	// nolint[gosec]: We need to support older TLS versions for AppleMail and Outlook.
 	return &tls.Config{
 		Certificates: []tls.Certificate{c},
 		ServerName:   "127.0.0.1",

internal/frontend/autoconfig/applemail.go

@@ -93,7 +93,7 @@ func (c *appleMail) Configure(imapPort, smtpPort int, imapSSL, smtpSSL bool, use
 	})()
 
 	// Make sure the file is only readable for the current user.
-	f, err := os.OpenFile(filepath.Join(dir, "protonmail.mobileconfig"), os.O_RDWR|os.O_CREATE, 0600)
+	f, err := os.OpenFile(filepath.Clean(filepath.Join(dir, "protonmail.mobileconfig")), os.O_RDWR|os.O_CREATE, 0600)
 	if err != nil {
 		return err
 	}

internal/frontend/cli-ie/accounts.go

@@ -25,7 +25,7 @@ import (
 
 func (f *frontendCLI) listAccounts(c *ishell.Context) {
 	spacing := "%-2d: %-20s (%-15s, %-15s)\n"
-	f.Printf(bold(strings.Replace(spacing, "d", "s", -1)), "#", "account", "status", "address mode")
+	f.Printf(bold(strings.ReplaceAll(spacing, "d", "s")), "#", "account", "status", "address mode")
 	for idx, user := range f.ie.GetUsers() {
 		connected := "disconnected"
 		if user.IsConnected() {

internal/frontend/cli-ie/importexport.go

@@ -38,7 +38,7 @@ func (f *frontendCLI) importLocalMessages(c *ishell.Context) {
 		return
 	}
 
-	t, err := f.ie.GetLocalImporter(user.GetPrimaryAddress(), path)
+	t, err := f.ie.GetLocalImporter(user.Username(), user.GetPrimaryAddress(), path)
 	f.transfer(t, err, false, true)
 }
 
@@ -68,7 +68,7 @@ func (f *frontendCLI) importRemoteMessages(c *ishell.Context) {
 		return
 	}
 
-	t, err := f.ie.GetRemoteImporter(user.GetPrimaryAddress(), username, password, host, port)
+	t, err := f.ie.GetRemoteImporter(user.Username(), user.GetPrimaryAddress(), username, password, host, port)
 	f.transfer(t, err, false, true)
 }
 
@@ -81,7 +81,7 @@ func (f *frontendCLI) exportMessagesToEML(c *ishell.Context) {
 		return
 	}
 
-	t, err := f.ie.GetEMLExporter(user.GetPrimaryAddress(), path)
+	t, err := f.ie.GetEMLExporter(user.Username(), user.GetPrimaryAddress(), path)
 	f.transfer(t, err, true, false)
 }
 
@@ -94,7 +94,7 @@ func (f *frontendCLI) exportMessagesToMBOX(c *ishell.Context) {
 		return
 	}
 
-	t, err := f.ie.GetMBOXExporter(user.GetPrimaryAddress(), path)
+	t, err := f.ie.GetMBOXExporter(user.Username(), user.GetPrimaryAddress(), path)
 	f.transfer(t, err, true, false)
 }
 

internal/frontend/cli/accounts.go

@@ -28,7 +28,7 @@ import (
 
 func (f *frontendCLI) listAccounts(c *ishell.Context) {
 	spacing := "%-2d: %-20s (%-15s, %-15s)\n"
-	f.Printf(bold(strings.Replace(spacing, "d", "s", -1)), "#", "account", "status", "address mode")
+	f.Printf(bold(strings.ReplaceAll(spacing, "d", "s")), "#", "account", "status", "address mode")
 	for idx, user := range f.bridge.GetUsers() {
 		connected := "disconnected"
 		if user.IsConnected() {

internal/frontend/cli/system.go

@@ -161,7 +161,7 @@ func (f *frontendCLI) disallowProxy(c *ishell.Context) {
 }
 
 func (f *frontendCLI) isPortFree(port string) bool {
-	port = strings.Replace(port, ":", "", -1)
+	port = strings.ReplaceAll(port, ":", "")
 	if port == "" || port == currentPort {
 		return true
 	}

internal/frontend/qml/GuiIE.qml

@@ -215,7 +215,7 @@ Item {
             }
             go.updateState = "updateRestart"
             winMain.dialogUpdate.finished(false)
-
+        
             // after manual update - just retart immidiatly
             go.setToRestart()
             Qt.quit()
@@ -236,13 +236,13 @@ Item {
             }
         }
 
-        onNotifySilentUpdateRestartNeeded: {
-            go.updateState = "updateRestart"
-        }
-
-        onNotifySilentUpdateError: {
-            go.updateState = "updateError"
-        }
+        //onNotifySilentUpdateRestartNeeded: {
+        //    go.updateState = "updateRestart"
+        //}
+        //
+        //onNotifySilentUpdateError: {
+        //    go.updateState = "updateError"
+        //}
 
         onNotifyLogout : {
             go.notifyBubble(0, qsTr("Account %1 has been disconnected. Please log in to continue to use the Import-Export app with this account.").arg(accname) )

internal/frontend/qml/ImportExportUI/AccountDelegate.qml

@@ -165,6 +165,7 @@ Column {
             textColor : Style.main.textBlue
             onClicked: {
                 dialogExport.currentIndex = 0
+                dialogExport.account = account
                 dialogExport.address = account
                 dialogExport.show()
             }
@@ -321,6 +322,7 @@ Column {
                         textBold: true
                         textColor: Style.main.textBlue
                         onClicked: {
+                            dialogExport.account = account
                             dialogExport.address = listalias[index]
                             dialogExport.show()
                         }
@@ -339,6 +341,7 @@ Column {
                         textBold: true
                         textColor: enabled ? Style.main.textBlue : Style.main.textDisabled
                         onClicked: {
+                            dialogImport.account = account
                             dialogImport.address = listalias[index]
                             dialogImport.show()
                         }

internal/frontend/qml/ImportExportUI/DialogExport.qml

@@ -35,6 +35,7 @@ Dialog {
 
     title : set_title()
 
+    property string account
     property string address
     property alias finish: finish
 
@@ -428,7 +429,7 @@ Dialog {
         onTriggered : {
             switch (currentIndex) {
                 case 0:
-                go.loadStructureForExport(root.address)
+                go.loadStructureForExport(root.account, root.address)
                 sourceFoldersInput.hasItems = (transferRules.rowCount() > 0)
                 break
                 case 2:

internal/frontend/qml/ImportExportUI/DialogImport.qml

@@ -34,6 +34,7 @@ Dialog {
 
     isDialogBusy: currentIndex==3 || currentIndex==4
 
+    property string account
     property string address
     property string inputPath  : ""
     property bool   isFromFile : inputEmail.text == "" && root.inputPath != ""
@@ -1032,6 +1033,7 @@ Dialog {
                     root.isFromIMAP,
                     root.inputPath,
                     inputEmail.text, inputPassword.text, inputServer.text, inputPort.text,
+                    root.account,
                     root.address
                 )
                 break

internal/frontend/qml/ImportExportUI/SettingsView.qml

@@ -96,6 +96,8 @@ Item {
                 onClicked: bugreportWin.show()
             }
 
+            /*
+
             ButtonIconText {
                 id: autoUpdates
                 text: qsTr("Keep the application up to date", "label for toggle that activates and disables the automatic updates")
@@ -115,8 +117,6 @@ Item {
                 }
             }
 
-            /*
-
              ButtonIconText {
                  id: cacheClear
                  text: qsTr("Clear Cache")

internal/frontend/qml/ProtonUI/Dialog.qml

@@ -18,6 +18,7 @@
 // Dialog with adding new user
 
 import QtQuick 2.8
+import QtQuick.Controls 2.1
 import QtQuick.Layouts 1.3
 import ProtonUI 1.0
 
@@ -83,6 +84,9 @@ StackLayout {
             text : ""
             color: Style.main.textBlue
             visible: false
+            width: root.width
+            horizontalAlignment: Text.AlignHCenter
+            wrapMode: Text.WordWrap
         }
 
         // prevent any action below

internal/frontend/qml/ProtonUI/DialogAddUser.qml

@@ -70,7 +70,8 @@ Dialog {
             id: topSep
             color  : "transparent"
             width  : Style.main.dummy
-            height : root.height/2 - (dialogNameAndPassword.heightInputs)/2
+            // Hacky hack: +10 is to make title of Dialog bigger so longer error can fit just fine.
+            height : root.height/2 + 10 - (dialogNameAndPassword.heightInputs)/2
         }
 
         InputField {

internal/frontend/qml/ProtonUI/DialogUpdate.qml

@@ -107,7 +107,7 @@ Dialog {
                 text: qsTr("Automatically update in the future", "Checkbox label for using autoupdates later on")
                 checked: go.isAutoUpdate
                 onToggled: go.toggleAutoUpdate()
-                visible: !root.forceUpdate
+                visible: !root.forceUpdate && (go.isAutoUpdate != undefined)
             }
 
             Row {

internal/frontend/qml/tst_GuiIE.qml

@@ -23,13 +23,13 @@ import QtQuick.Window 2.2
 
 Window {
     id      : testroot
-    width   : 100
+    width   : 150
     height  : 600
     flags   : Qt.Window | Qt.Dialog | Qt.FramelessWindowHint
     visible : true
     title   : "GUI test Window"
     color   : "transparent"
-    x       : testgui.winMain.x - 120
+    x       : testgui.winMain.x - 170
     y       : testgui.winMain.y
 
     property bool newVersion : true
@@ -110,8 +110,8 @@ Window {
         ListElement { title: "NotifyManualUpdateRestart" }
         ListElement { title: "NotifyManualUpdateError" }
         ListElement { title: "ForceUpdate" }
-        ListElement { title: "NotifySilentUpdateRestartNeeded" }
-        ListElement { title: "NotifySilentUpdateError" }
+        //ListElement { title: "NotifySilentUpdateRestartNeeded" }
+        //ListElement { title: "NotifySilentUpdateError" }
         ListElement { title : "ImportStructure"     }
         ListElement { title : "DraftImpFailed"      }
         ListElement { title : "NoInterImp"          }
@@ -183,12 +183,12 @@ Window {
                     case "ForceUpdate" :
                     go.notifyForceUpdate()
                     break;
-                    case "NotifySilentUpdateRestartNeeded" :
-                    go.notifySilentUpdateRestartNeeded()
-                    break;
-                    case "NotifySilentUpdateError" :
-                    go.notifySilentUpdateError()
-                    break;
+                    //case "NotifySilentUpdateRestartNeeded" :
+                    //go.notifySilentUpdateRestartNeeded()
+                    //break;
+                    //case "NotifySilentUpdateError" :
+                    //go.notifySilentUpdateError()
+                    //break;
                     case "ImportStructure" :
                     testgui.winMain.dialogImport.address = "cuto@pm.com"
                     testgui.winMain.dialogImport.show()
@@ -836,7 +836,7 @@ Window {
         id: go
 
         property int isAutoStart : 1
-        property bool isAutoUpdate : false
+        //property bool isAutoUpdate : false
         property bool isFirstStart : false
         property string currentAddress : "none"
         //property string goos : "windows"
@@ -858,15 +858,15 @@ Window {
 
         property string updateState
         property string updateVersion : "q0.1.0"
-        property bool updateCanInstall: true
+        property bool updateCanInstall: false
         property string updateLandingPage : "https://protonmail.com/import-export/download/"
         property string updateReleaseNotesLink  : "https://protonmail.com/download/ie/release_notes.html"
         signal notifyManualUpdate()
         signal notifyManualUpdateRestartNeeded()
         signal notifyManualUpdateError()
         signal notifyForceUpdate()
-        signal notifySilentUpdateRestartNeeded()
-        signal notifySilentUpdateError()
+        //signal notifySilentUpdateRestartNeeded()
+        //signal notifySilentUpdateError()
         function checkForUpdates() {
             console.log("checkForUpdates")
             go.notifyVersionIsTheLatest()
@@ -1355,10 +1355,10 @@ Window {
             return !fname.includes("fail")
         }
 
-        onToggleAutoUpdate: {
-            workAndClose()
-            isAutoUpdate = (isAutoUpdate!=false) ? false : true
-            console.log (" Test: onToggleAutoUpdate "+isAutoUpdate)
-        }
+        //onToggleAutoUpdate: {
+        //    workAndClose()
+        //    isAutoUpdate = (isAutoUpdate!=false) ? false : true
+        //    console.log (" Test: onToggleAutoUpdate "+isAutoUpdate)
+        //}
     }
 }

internal/frontend/qt-ie/export.go

@@ -29,7 +29,7 @@ const (
 	TypeMBOX = "MBOX"
 )
 
-func (f *FrontendQt) LoadStructureForExport(addressOrID string) {
+func (f *FrontendQt) LoadStructureForExport(username, addressOrID string) {
 	errCode := errUnknownError
 	var err error
 	defer func() {
@@ -41,7 +41,7 @@ func (f *FrontendQt) LoadStructureForExport(addressOrID string) {
 		}
 	}()
 
-	if f.transfer, err = f.ie.GetEMLExporter(addressOrID, ""); err != nil {
+	if f.transfer, err = f.ie.GetEMLExporter(username, addressOrID, ""); err != nil {
 		// The only error can be problem to load PM user and address.
 		errCode = errPMLoadFailed
 		return

internal/frontend/qt-ie/frontend.go

@@ -135,11 +135,11 @@ func (f *FrontendQt) SetVersion(version updater.VersionInfo) {
 }
 
 func (f *FrontendQt) NotifySilentUpdateInstalled() {
-	f.Qml.NotifySilentUpdateRestartNeeded()
+	//f.Qml.NotifySilentUpdateRestartNeeded()
 }
 
 func (f *FrontendQt) NotifySilentUpdateError(err error) {
-	f.Qml.NotifySilentUpdateError()
+	//f.Qml.NotifySilentUpdateError()
 }
 
 func (f *FrontendQt) watchEvents() {
@@ -245,11 +245,11 @@ func (f *FrontendQt) QtExecute(Procedure func(*FrontendQt) error) error {
 	f.Qml.SetCredits(importexport.Credits)
 	f.Qml.SetFullversion(f.buildVersion)
 
-	if f.settings.GetBool(settings.AutoUpdateKey) {
-		f.Qml.SetIsAutoUpdate(true)
-	} else {
-		f.Qml.SetIsAutoUpdate(false)
-	}
+	//if f.settings.GetBool(settings.AutoUpdateKey) {
+	//	f.Qml.SetIsAutoUpdate(true)
+	//} else {
+	//	f.Qml.SetIsAutoUpdate(false)
+	//}
 
 	go func() {
 		defer f.panicHandler.HandlePanic()
@@ -339,17 +339,17 @@ func (f *FrontendQt) sendBug(description, emailClient, address string) bool {
 	return true
 }
 
-func (f *FrontendQt) toggleAutoUpdate() {
-	defer f.Qml.ProcessFinished()
-
-	if f.settings.GetBool(settings.AutoUpdateKey) {
-		f.settings.SetBool(settings.AutoUpdateKey, false)
-		f.Qml.SetIsAutoUpdate(false)
-	} else {
-		f.settings.SetBool(settings.AutoUpdateKey, true)
-		f.Qml.SetIsAutoUpdate(true)
-	}
-}
+//func (f *FrontendQt) toggleAutoUpdate() {
+//	defer f.Qml.ProcessFinished()
+//
+//	if f.settings.GetBool(settings.AutoUpdateKey) {
+//		f.settings.SetBool(settings.AutoUpdateKey, false)
+//		f.Qml.SetIsAutoUpdate(false)
+//	} else {
+//		f.settings.SetBool(settings.AutoUpdateKey, true)
+//		f.Qml.SetIsAutoUpdate(true)
+//	}
+//}
 
 // checkInternet is almost idetical to bridge
 func (f *FrontendQt) checkInternet() {

internal/frontend/qt-ie/import.go

@@ -26,7 +26,7 @@ import (
 )
 
 // wrapper for QML
-func (f *FrontendQt) setupAndLoadForImport(isFromIMAP bool, sourcePath, sourceEmail, sourcePassword, sourceServer, sourcePort, targetAddress string) {
+func (f *FrontendQt) setupAndLoadForImport(isFromIMAP bool, sourcePath, sourceEmail, sourcePassword, sourceServer, sourcePort, targetUsername, targetAddress string) {
 	errCode := errUnknownError
 	var err error
 	defer func() {
@@ -39,7 +39,7 @@ func (f *FrontendQt) setupAndLoadForImport(isFromIMAP bool, sourcePath, sourceEm
 	}()
 
 	if isFromIMAP {
-		f.transfer, err = f.ie.GetRemoteImporter(targetAddress, sourceEmail, sourcePassword, sourceServer, sourcePort)
+		f.transfer, err = f.ie.GetRemoteImporter(targetUsername, targetAddress, sourceEmail, sourcePassword, sourceServer, sourcePort)
 		if err != nil {
 			switch {
 			case errors.Is(err, &transfer.ErrIMAPConnection{}):
@@ -54,7 +54,7 @@ func (f *FrontendQt) setupAndLoadForImport(isFromIMAP bool, sourcePath, sourceEm
 			return
 		}
 	} else {
-		f.transfer, err = f.ie.GetLocalImporter(targetAddress, sourcePath)
+		f.transfer, err = f.ie.GetLocalImporter(targetUsername, targetAddress, sourcePath)
 		if err != nil {
 			// The only error can be problem to load PM user and address.
 			errCode = errPMLoadFailed

internal/frontend/qt-ie/ui.go

@@ -33,7 +33,7 @@ type GoQMLInterface struct {
 
 	_ func() `constructor:"init"`
 
-	_ bool   `property:"isAutoUpdate"`
+	//_ bool   `property:"isAutoUpdate"`
 	_ string `property:"currentAddress"`
 	_ string `property:"goos"`
 	_ string `property:"credits"`
@@ -62,8 +62,8 @@ type GoQMLInterface struct {
 	_ func() `signal:"notifyManualUpdateRestartNeeded"`
 	_ func() `signal:"notifyManualUpdateError"`
 	_ func() `signal:"notifyForceUpdate"`
-	_ func() `signal:"notifySilentUpdateRestartNeeded"`
-	_ func() `signal:"notifySilentUpdateError"`
+	//_ func() `signal:"notifySilentUpdateRestartNeeded"`
+	//_ func() `signal:"notifySilentUpdateError"`
 	_ func() `slot:"checkForUpdates"`
 	_ func() `slot:"checkAndOpenReleaseNotes"`
 	_ func() `signal:"openReleaseNotesExternally"`
@@ -77,8 +77,8 @@ type GoQMLInterface struct {
 	_ string `property:"credentialsNotRemoved"`
 	_ string `property:"versionCheckFailed"`
 	//
-	_ func(isAvailable bool)   `signal:"setConnectionStatus"`
-	_ func()                   `slot:"checkInternet"`
+	_ func(isAvailable bool) `signal:"setConnectionStatus"`
+	_ func()                 `slot:"checkInternet"`
 
 	_ func() `slot:"setToRestart"`
 
@@ -93,7 +93,7 @@ type GoQMLInterface struct {
 
 	_ func() `signal:"showWindow"`
 
-	_ func() `slot:"toggleAutoUpdate"`
+	//_ func() `slot:"toggleAutoUpdate"`
 	_ func() `slot:"quit"`
 	_ func() `slot:"loadAccounts"`
 	_ func() `slot:"openLogs"`
@@ -108,14 +108,14 @@ type GoQMLInterface struct {
 
 	_ func(description, client, address string) bool                                       `slot:"sendBug"`
 	_ func(address string) bool                                                            `slot:"sendImportReport"`
-	_ func(address string)                                                                 `slot:"loadStructureForExport"`
+	_ func(username, address string)                                                       `slot:"loadStructureForExport"`
 	_ func() string                                                                        `slot:"leastUsedColor"`
 	_ func(username string, name string, color string, isLabel bool, sourceID string) bool `slot:"createLabelOrFolder"`
 	_ func(fpath, address, fileType string, attachEncryptedBody bool)                      `slot:"startExport"`
 	_ func(email string, importEncrypted bool)                                             `slot:"startImport"`
 	_ func()                                                                               `slot:"resetSource"`
 
-	_ func(isFromIMAP bool, sourcePath, sourceEmail, sourcePassword, sourceServe, sourcePort, targetAddress string) `slot:"setupAndLoadForImport"`
+	_ func(isFromIMAP bool, sourcePath, sourceEmail, sourcePassword, sourceServe, sourcePort, targetUsername, targetAddress string) `slot:"setupAndLoadForImport"`
 
 	_ string `property:"progressInit"`
 
@@ -162,7 +162,7 @@ func (s *GoQMLInterface) init() {}
 func (s *GoQMLInterface) SetFrontend(f *FrontendQt) {
 	s.ConnectQuit(f.App.Quit)
 
-	s.ConnectToggleAutoUpdate(f.toggleAutoUpdate)
+	//s.ConnectToggleAutoUpdate(f.toggleAutoUpdate)
 	s.ConnectLoadAccounts(f.Accounts.LoadAccounts)
 	s.ConnectOpenLogs(f.openLogs)
 	s.ConnectOpenDownloadLink(f.openDownloadLink)
@@ -207,4 +207,6 @@ func (s *GoQMLInterface) SetFrontend(f *FrontendQt) {
 	s.ConnectCheckPathStatus(CheckPathStatus)
 
 	s.ConnectEmitEvent(f.emitEvent)
+
+	s.ConnectStartManualUpdate(f.startManualUpdate)
 }

internal/frontend/qt/frontend.go

@@ -370,24 +370,15 @@ func (s *FrontendQt) qtExecute(Procedure func(*FrontendQt) error) error {
 	}
 	s.Qml.SetIsAutoStart(s.autostart.IsEnabled())
 
-	if s.settings.GetBool(settings.AllowProxyKey) {
-		s.Qml.SetIsProxyAllowed(true)
-	} else {
-		s.Qml.SetIsProxyAllowed(false)
-	}
-
-	if updater.UpdateChannel(s.settings.Get(settings.UpdateChannelKey)) == updater.EarlyChannel {
-		s.Qml.SetIsEarlyAccess(true)
-	} else {
-		s.Qml.SetIsEarlyAccess(false)
-	}
+	s.Qml.SetIsAutoUpdate(s.settings.GetBool(settings.AutoUpdateKey))
+	s.Qml.SetIsProxyAllowed(s.settings.GetBool(settings.AllowProxyKey))
+	s.Qml.SetIsEarlyAccess(updater.UpdateChannel(s.settings.Get(settings.UpdateChannelKey)) == updater.EarlyChannel)
 
 	availableKeychain := []string{}
 	for chain := range keychain.Helpers {
 		availableKeychain = append(availableKeychain, chain)
 	}
 	s.Qml.SetAvailableKeychain(availableKeychain)
-
 	s.Qml.SetSelectedKeychain(s.settings.Get(settings.PreferredKeychainKey))
 
 	// Set reporting of outgoing email without encryption.

internal/frontend/share/icon.rc

@@ -1 +0,0 @@
-IDI_ICON1 ICON DISCARDABLE "logo.ico"

internal/frontend/share/info.rc

@@ -0,0 +1,45 @@
+#define STRINGIZE_(x) #x
+#define STRINGIZE(x) STRINGIZE_(x)
+
+IDI_ICON1 ICON DISCARDABLE STRINGIZE(ICO_FILE)
+
+#if defined BUILD_BRIDGE
+    #define FILE_COMMENTS "The Bridge is an application that runs on your computer in the background and seamlessly encrypts and decrypts your mail as it enters and leaves your computer."
+    #define FILE_DESCRIPTION "ProtonMail Bridge"
+    #define INTERNAL_NAME STRINGIZE(EXE_NAME)
+    #define PRODUCT_NAME "ProtonMail Bridge for Windows"
+#elif defined BUILD_IE
+    #define FILE_COMMENTS "The Import-Export app helps you to migrate your emails from local files or remote IMAP servers to ProtonMail or simply export emails to local folder."
+    #define FILE_DESCRIPTION "ProtonMail Import-Export app"
+    #define INTERNAL_NAME STRINGIZE(EXE_NAME)
+    #define PRODUCT_NAME "ProtonMail Import-Export app for Windows"
+#else
+    #error No target specified
+#endif
+
+#define LEGAL_COPYRIGHT "(C) " STRINGIZE(YEAR) " Proton Technologies AG"
+
+1 VERSIONINFO
+FILEVERSION     FILE_VERSION_COMMA,0
+PRODUCTVERSION  FILE_VERSION_COMMA,0
+BEGIN
+    BLOCK "StringFileInfo"
+    BEGIN
+        BLOCK "040904b0"
+        BEGIN
+            VALUE "Comments", FILE_COMMENTS
+            VALUE "CompanyName", "Proton Technologies AG"
+            VALUE "FileDescription", FILE_DESCRIPTION
+            VALUE "FileVersion", STRINGIZE(FILE_VERSION)
+            VALUE "InternalName", INTERNAL_NAME
+            VALUE "LegalCopyright", LEGAL_COPYRIGHT
+            VALUE "OriginalFilename", STRINGIZE(ORIGINAL_FILE_NAME)
+            VALUE "ProductName", PRODUCT_NAME
+            VALUE "ProductVersion", STRINGIZE(PRODUCT_VERSION)
+        END
+    END
+    BLOCK "VarFileInfo"
+    BEGIN
+        VALUE "Translation", 0x0409, 0x04B0
+    END
+END

internal/frontend/types/types.go

@@ -114,10 +114,10 @@ func (b *bridgeWrap) GetUser(query string) (User, error) {
 type ImportExporter interface {
 	UserManager
 
-	GetLocalImporter(string, string) (*transfer.Transfer, error)
-	GetRemoteImporter(string, string, string, string, string) (*transfer.Transfer, error)
-	GetEMLExporter(string, string) (*transfer.Transfer, error)
-	GetMBOXExporter(string, string) (*transfer.Transfer, error)
+	GetLocalImporter(string, string, string) (*transfer.Transfer, error)
+	GetRemoteImporter(string, string, string, string, string, string) (*transfer.Transfer, error)
+	GetEMLExporter(string, string, string) (*transfer.Transfer, error)
+	GetMBOXExporter(string, string, string) (*transfer.Transfer, error)
 	ReportBug(osType, osVersion, description, accountName, address, emailClient string) error
 	ReportFile(osType, osVersion, accountName, address string, logdata []byte) error
 }

internal/imap/backend.go

@@ -16,6 +16,19 @@
 // along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
 
 // Package imap provides IMAP server of the Bridge.
+//
+// Methods are called by the go-imap library in parallel.
+// Additional parallelism is achieved while handling each IMAP request.
+//
+// For example, ListMessages internally uses `fetchWorkers` workers to resolve each requested item.
+// When IMAP clients request message literals (or parts thereof), we sometimes need to build RFC822 message literals.
+// To do this, we pass build jobs to the message builder, which internally manages its own parallelism.
+// Summary:
+//  - each IMAP fetch request is handled in parallel,
+//  - within each IMAP fetch request, individual items are handled by a pool of `fetchWorkers` workers,
+//  - within each worker, build jobs are posted to the message builder,
+//  - the message builder handles build jobs using its own, independent worker pool,
+// The builder will handle jobs in parallel up to its own internal limit. This prevents it from overwhelming API.
 package imap
 
 import (
@@ -26,10 +39,19 @@ import (
 	"github.com/ProtonMail/proton-bridge/internal/bridge"
 	"github.com/ProtonMail/proton-bridge/internal/events"
 	"github.com/ProtonMail/proton-bridge/pkg/listener"
+	"github.com/ProtonMail/proton-bridge/pkg/message"
 	"github.com/emersion/go-imap"
 	goIMAPBackend "github.com/emersion/go-imap/backend"
 )
 
+const (
+	// NOTE: Each fetch worker has its own set of attach workers so there can be up to 20*5=100 API requests at once.
+	// This is a reasonable limit to not overwhelm API while still maintaining as much parallelism as possible.
+	fetchWorkers  = 20 // In how many workers to fetch message (group list on IMAP).
+	attachWorkers = 5  // In how many workers to fetch attachments (for one message).
+	buildWorkers  = 20 // In how many workers to build messages.
+)
+
 type panicHandler interface {
 	HandlePanic()
 }
@@ -43,6 +65,8 @@ type imapBackend struct {
 	users       map[string]*imapUser
 	usersLocker sync.Locker
 
+	builder *message.Builder
+
 	imapCache     map[string]map[string]string
 	imapCachePath string
 	imapCacheLock *sync.RWMutex
@@ -78,6 +102,8 @@ func newIMAPBackend(
 		users:       map[string]*imapUser{},
 		usersLocker: &sync.Mutex{},
 
+		builder: message.NewBuilder(fetchWorkers, attachWorkers, buildWorkers),
+
 		imapCachePath: cache.GetIMAPCachePath(),
 		imapCacheLock: &sync.RWMutex{},
 	}

internal/imap/bridge.go

@@ -61,7 +61,7 @@ func (b *bridgeWrap) GetUser(query string) (bridgeUser, error) {
 	if err != nil {
 		return nil, err
 	}
-	return newBridgeUserWrap(user), nil
+	return newBridgeUserWrap(user), nil //nolint[typecheck] missing methods are inherited
 }
 
 type bridgeUserWrap struct {
@@ -77,5 +77,5 @@ func (u *bridgeUserWrap) GetStore() storeUserProvider {
 	if store == nil {
 		return nil
 	}
-	return newStoreUserWrap(store)
+	return newStoreUserWrap(store) //nolint[typecheck] missing methods are inherited
 }

internal/imap/id/extension.go

@@ -26,7 +26,7 @@ type currentClientSetter interface {
 	SetClient(name, version string)
 }
 
-// Extension for IMAP server
+// Extension for IMAP server.
 type extension struct {
 	extID        imapserver.ConnExtension
 	clientSetter currentClientSetter

internal/imap/imap.go

@@ -19,11 +19,4 @@ package imap
 
 import "github.com/sirupsen/logrus"
 
-const (
-	fetchMessagesWorkers    = 5 // In how many workers to fetch message (group list on IMAP).
-	fetchAttachmentsWorkers = 5 // In how many workers to fetch attachments (for one message).
-)
-
-var (
-	log = logrus.WithField("pkg", "imap") //nolint[gochecknoglobals]
-)
+var log = logrus.WithField("pkg", "imap") //nolint[gochecknoglobals]

internal/imap/mailbox.go

@@ -37,10 +37,12 @@ type imapMailbox struct {
 	storeUser    storeUserProvider
 	storeAddress storeAddressProvider
 	storeMailbox storeMailboxProvider
+
+	builder *message.Builder
 }
 
 // newIMAPMailbox returns struct implementing go-imap/mailbox interface.
-func newIMAPMailbox(panicHandler panicHandler, user *imapUser, storeMailbox storeMailboxProvider) *imapMailbox {
+func newIMAPMailbox(panicHandler panicHandler, user *imapUser, storeMailbox storeMailboxProvider, builder *message.Builder) *imapMailbox {
 	return &imapMailbox{
 		panicHandler: panicHandler,
 		user:         user,
@@ -54,6 +56,8 @@ func newIMAPMailbox(panicHandler panicHandler, user *imapUser, storeMailbox stor
 		storeUser:    user.storeUser,
 		storeAddress: user.storeAddress,
 		storeMailbox: storeMailbox,
+
+		builder: builder,
 	}
 }
 

internal/imap/mailbox_message.go

@@ -19,9 +19,9 @@ package imap
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
-	"mime/multipart"
 	"net/mail"
 	"net/textproto"
 	"sort"
@@ -32,12 +32,10 @@ import (
 	"github.com/ProtonMail/proton-bridge/internal/imap/cache"
 	"github.com/ProtonMail/proton-bridge/internal/imap/uidplus"
 	"github.com/ProtonMail/proton-bridge/pkg/message"
-	"github.com/ProtonMail/proton-bridge/pkg/parallel"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 	"github.com/emersion/go-imap"
 	"github.com/hashicorp/go-multierror"
 	"github.com/pkg/errors"
-	openpgperrors "golang.org/x/crypto/openpgp/errors"
 )
 
 var (
@@ -181,7 +179,7 @@ func (im *imapMailbox) createMessage(flags []string, date time.Time, body imap.L
 				return err
 			}
 
-			targetSeq := im.storeMailbox.GetUIDList([]string{m.ID})
+			targetSeq := im.storeMailbox.GetUIDList(IDs)
 			return uidplus.AppendResponse(im.storeMailbox.UIDValidity(), targetSeq)
 		}
 	}
@@ -226,8 +224,9 @@ func (im *imapMailbox) importMessage(m *pmapi.Message, readers []io.Reader, kr *
 	return im.storeMailbox.ImportMessage(m, body, labels)
 }
 
-func (im *imapMailbox) getMessage(storeMessage storeMessageProvider, items []imap.FetchItem) (msg *imap.Message, err error) {
-	im.log.WithField("msgID", storeMessage.ID()).Trace("Getting message")
+func (im *imapMailbox) getMessage(storeMessage storeMessageProvider, items []imap.FetchItem, msgBuildCountHistogram *msgBuildCountHistogram) (msg *imap.Message, err error) { //nolint[funlen]
+	msglog := im.log.WithField("msgID", storeMessage.ID())
+	msglog.Trace("Getting message")
 
 	seqNum, err := storeMessage.SequenceNumber()
 	if err != nil {
@@ -240,7 +239,9 @@ func (im *imapMailbox) getMessage(storeMessage storeMessageProvider, items []ima
 	for _, item := range items {
 		switch item {
 		case imap.FetchEnvelope:
-			msg.Envelope = message.GetEnvelope(m)
+			// No need to check IsFullHeaderCached here. API header
+			// contain enough information to build the envelope.
+			msg.Envelope = message.GetEnvelope(m, storeMessage.GetHeader())
 		case imap.FetchBody, imap.FetchBodyStructure:
 			var structure *message.BodyStructure
 			structure, err = im.getBodyStructure(storeMessage)
@@ -267,8 +268,13 @@ func (im *imapMailbox) getMessage(storeMessage storeMessageProvider, items []ima
 			// Size attribute on the server counts encrypted data. The value is cleared
 			// on our part and we need to compute "real" size of decrypted data.
 			if m.Size <= 0 {
-				im.log.WithField("msgID", storeMessage.ID()).Trace("Size unknown - downloading body")
-				if _, _, err = im.getBodyAndStructure(storeMessage); err != nil {
+				msglog.Debug("Size unknown - downloading body")
+				// We are sure the size is not a problem right now. Clients
+				// might not first check sizes of all messages so we couldn't
+				// be sure if seeing 1st or 2nd sync is all right or not.
+				// Therefore, it's better to exclude getting size from the
+				// counting and see build count as real message build.
+				if _, _, err = im.getBodyAndStructure(storeMessage, nil); err != nil {
 					return
 				}
 			}
@@ -278,8 +284,10 @@ func (im *imapMailbox) getMessage(storeMessage storeMessageProvider, items []ima
 			if err != nil {
 				return nil, err
 			}
+		case imap.FetchAll, imap.FetchFast, imap.FetchFull, imap.FetchRFC822, imap.FetchRFC822Header, imap.FetchRFC822Text:
+			fallthrough // this is list of defined items by go-imap, but items can be also sections generated from requests
 		default:
-			if err = im.getLiteralForSection(item, msg, storeMessage); err != nil {
+			if err = im.getLiteralForSection(item, msg, storeMessage, msgBuildCountHistogram); err != nil {
 				return
 			}
 		}
@@ -288,14 +296,15 @@ func (im *imapMailbox) getMessage(storeMessage storeMessageProvider, items []ima
 	return msg, err
 }
 
-func (im *imapMailbox) getLiteralForSection(itemSection imap.FetchItem, msg *imap.Message, storeMessage storeMessageProvider) error {
+func (im *imapMailbox) getLiteralForSection(itemSection imap.FetchItem, msg *imap.Message, storeMessage storeMessageProvider, msgBuildCountHistogram *msgBuildCountHistogram) error {
 	section, err := imap.ParseBodySectionName(itemSection)
-	if err != nil { // Ignore error
-		return nil
+	if err != nil {
+		log.WithError(err).Warn("Failed to parse body section name; part will be skipped")
+		return nil //nolint[nilerr] ignore error
 	}
 
 	var literal imap.Literal
-	if literal, err = im.getMessageBodySection(storeMessage, section); err != nil {
+	if literal, err = im.getMessageBodySection(storeMessage, section, msgBuildCountHistogram); err != nil {
 		return err
 	}
 
@@ -313,14 +322,20 @@ func (im *imapMailbox) getBodyStructure(storeMessage storeMessageProvider) (bs *
 		im.log.WithError(err).Debug("Fail to retrieve bodystructure from database")
 	}
 	if bs == nil {
-		if bs, _, err = im.getBodyAndStructure(storeMessage); err != nil {
+		// We are sure the body structure is not a problem right now.
+		// Clients might do first fetch body structure so we couldn't
+		// be sure if seeing 1st or 2nd sync is all right or not.
+		// Therefore, it's better to exclude first body structure fetch
+		// from the counting and see build count as real message build.
+		if bs, _, err = im.getBodyAndStructure(storeMessage, nil); err != nil {
 			return
 		}
 	}
 	return
 }
 
-func (im *imapMailbox) getBodyAndStructure(storeMessage storeMessageProvider) (
+//nolint[funlen] Jakub will fix in refactor
+func (im *imapMailbox) getBodyAndStructure(storeMessage storeMessageProvider, msgBuildCountHistogram *msgBuildCountHistogram) (
 	structure *message.BodyStructure,
 	bodyReader *bytes.Reader, err error,
 ) {
@@ -347,10 +362,26 @@ func (im *imapMailbox) getBodyAndStructure(storeMessage storeMessageProvider) (
 			}
 		}
 		if err == nil && structure != nil && len(body) > 0 {
-			if err := storeMessage.SetContentTypeAndHeader(m.MIMEType, m.Header); err != nil {
-				im.log.WithError(err).
+			header, errHead := structure.GetMailHeaderBytes(bytes.NewReader(body))
+			if errHead == nil {
+				if errHead := storeMessage.SetHeader(header); errHead != nil {
+					im.log.WithError(errHead).
+						WithField("msgID", m.ID).
+						Warn("Cannot update header after building")
+				}
+			} else {
+				im.log.WithError(errHead).
 					WithField("msgID", m.ID).
-					Warn("Cannot update header while building")
+					Warn("Cannot get header bytes after building")
+			}
+			if msgBuildCountHistogram != nil {
+				times, err := storeMessage.IncreaseBuildCount()
+				if err != nil {
+					im.log.WithError(err).
+						WithField("msgID", m.ID).
+						Warn("Cannot increase build count")
+				}
+				msgBuildCountHistogram.add(times)
 			}
 			// Drafts can change and we don't want to cache them.
 			if !isMessageInDraftFolder(m) {
@@ -379,40 +410,32 @@ func isMessageInDraftFolder(m *pmapi.Message) bool {
 
 // This will download message (or read from cache) and pick up the section,
 // extract data (header,body, both) and trim the output if needed.
-func (im *imapMailbox) getMessageBodySection(storeMessage storeMessageProvider, section *imap.BodySectionName) (literal imap.Literal, err error) { // nolint[funlen]
-	var (
-		structure  *message.BodyStructure
-		bodyReader *bytes.Reader
-		header     textproto.MIMEHeader
-		response   []byte
-	)
+func (im *imapMailbox) getMessageBodySection(
+	storeMessage storeMessageProvider,
+	section *imap.BodySectionName,
+	msgBuildCountHistogram *msgBuildCountHistogram,
+) (imap.Literal, error) {
+	var header textproto.MIMEHeader
+	var response []byte
 
 	im.log.WithField("msgID", storeMessage.ID()).Trace("Getting message body")
 
-	m := storeMessage.Message()
-
-	if len(section.Path) == 0 && section.Specifier == imap.HeaderSpecifier {
-		// We can extract message header without decrypting.
-		header = message.GetHeader(m)
-		// We need to ensure we use the correct content-type,
-		// otherwise AppleMail expects `text/plain` in HTML mails.
-		if header.Get("Content-Type") == "" {
-			if err = im.fetchMessage(m); err != nil {
-				return
-			}
-			if _, err = im.setMessageContentType(m); err != nil {
-				return
-			}
-			if err = storeMessage.SetContentTypeAndHeader(m.MIMEType, m.Header); err != nil {
-				return
-			}
-			header = message.GetHeader(m)
-		}
+	isMainHeaderRequested := len(section.Path) == 0 && section.Specifier == imap.HeaderSpecifier
+	if isMainHeaderRequested && storeMessage.IsFullHeaderCached() {
+		// In order to speed up (avoid download and decryptions) we
+		// cache the header. If a mail header was requested and DB
+		// contains full header (it means it was already built once)
+		// the DB header can be used without downloading and decrypting.
+		// Otherwise header is incomplete and clients would have issues
+		// e.g. AppleMail expects `text/plain` in HTML mails.
+		header = storeMessage.GetHeader()
 	} else {
-		// The rest of cases need download and decrypt.
-		structure, bodyReader, err = im.getBodyAndStructure(storeMessage)
+		// For all other cases it is necessary to download and decrypt the message
+		// and drop the header which was obtained from cache. The header will
+		// will be stored in DB once successfully built. Check `getBodyAndStructure`.
+		structure, bodyReader, err := im.getBodyAndStructure(storeMessage, msgBuildCountHistogram)
 		if err != nil {
-			return
+			return nil, err
 		}
 
 		switch {
@@ -423,368 +446,86 @@ func (im *imapMailbox) getMessageBodySection(storeMessage storeMessageProvider,
 			// The TEXT specifier refers to the content of the message (or section), omitting the [RFC-2822] header.
 			// Non-empty section with no specifier (imap.EntireSpecifier) refers to section content without header.
 			response, err = structure.GetSectionContent(bodyReader, section.Path)
-		case section.Specifier == imap.MIMESpecifier:
-			// The MIME part specifier refers to the [MIME-IMB] header for this part.
+		case section.Specifier == imap.MIMESpecifier: // The MIME part specifier refers to the [MIME-IMB] header for this part.
 			fallthrough
 		case section.Specifier == imap.HeaderSpecifier:
 			header, err = structure.GetSectionHeader(section.Path)
 		default:
 			err = errors.New("Unknown specifier " + string(section.Specifier))
 		}
+
+		if err != nil {
+			return nil, err
+		}
 	}
 
-	if err != nil {
-		return
-	}
-
-	// Filter header. Options are: all fields, only selected fields, all fields except selected.
 	if header != nil {
-		// remove fields
-		if len(section.Fields) != 0 && section.NotFields {
-			for _, field := range section.Fields {
-				header.Del(field)
-			}
-		}
-
-		fields := make([]string, 0, len(header))
-		if len(section.Fields) == 0 || section.NotFields { // add all and sort
-			for f := range header {
-				fields = append(fields, f)
-			}
-			sort.Strings(fields)
-		} else { // add only requested (in requested order)
-			for _, f := range section.Fields {
-				fields = append(fields, textproto.CanonicalMIMEHeaderKey(f))
-			}
-		}
-
-		headerBuf := &bytes.Buffer{}
-		for _, canonical := range fields {
-			if values, ok := header[canonical]; !ok {
-				continue
-			} else {
-				for _, val := range values {
-					fmt.Fprintf(headerBuf, "%s: %s\r\n", canonical, val)
-				}
-			}
-		}
-		response = headerBuf.Bytes()
+		response = filteredHeaderAsBytes(header, section)
 	}
 
 	// Trim any output if requested.
-	literal = bytes.NewBuffer(section.ExtractPartial(response))
-	return literal, nil
+	return bytes.NewBuffer(section.ExtractPartial(response)), nil
 }
 
-func (im *imapMailbox) fetchMessage(m *pmapi.Message) (err error) {
-	im.log.Trace("Fetching message")
-
-	complete, err := im.storeMailbox.FetchMessage(m.ID)
-	if err != nil {
-		im.log.WithError(err).Error("Could not get message from store")
-		return
-	}
-
-	*m = *complete.Message()
-
-	return
-}
-
-func (im *imapMailbox) writeMessageBody(w io.Writer, m *pmapi.Message) (err error) {
-	im.log.Trace("Writing message body")
-
-	if m.Body == "" {
-		im.log.Trace("While writing message body, noticed message body is null, need to fetch")
-		if err = im.fetchMessage(m); err != nil {
-			return
+// filteredHeaderAsBytes filters the header fields by section fields and it
+// returns the filtered fields as bytes.
+// Options are: all fields, only selected fields, all fields except selected.
+func filteredHeaderAsBytes(header textproto.MIMEHeader, section *imap.BodySectionName) []byte {
+	// remove fields
+	if len(section.Fields) != 0 && section.NotFields {
+		for _, field := range section.Fields {
+			header.Del(field)
 		}
 	}
 
-	kr, err := im.user.client().KeyRingForAddressID(m.AddressID)
-	if err != nil {
-		return errors.Wrap(err, "failed to get keyring for address ID")
-	}
-
-	err = message.WriteBody(w, kr, m)
-	if err != nil {
-		if customMessageErr := message.CustomMessage(m, err, true); customMessageErr != nil {
-			im.log.WithError(customMessageErr).Warn("Failed to make custom message")
+	fields := make([]string, 0, len(header))
+	if len(section.Fields) == 0 || section.NotFields { // add all and sort
+		for f := range header {
+			fields = append(fields, f)
 		}
-		_, _ = io.WriteString(w, m.Body)
-		err = nil
-	}
-
-	return
-}
-
-func (im *imapMailbox) writeAttachmentBody(w io.Writer, m *pmapi.Message, att *pmapi.Attachment) (err error) {
-	// Retrieve encrypted attachment.
-	r, err := im.user.client().GetAttachment(att.ID)
-	if err != nil {
-		return
-	}
-	defer r.Close() //nolint[errcheck]
-
-	kr, err := im.user.client().KeyRingForAddressID(m.AddressID)
-	if err != nil {
-		return errors.Wrap(err, "failed to get keyring for address ID")
-	}
-
-	if err = message.WriteAttachmentBody(w, kr, m, att, r); err != nil {
-		// Returning an error here makes certain mail clients behave badly,
-		// trying to retrieve the message again and again.
-		im.log.Warn("Cannot write attachment body: ", err)
-		err = nil
-	}
-	return
-}
-
-func (im *imapMailbox) writeRelatedPart(p io.Writer, m *pmapi.Message, inlines []*pmapi.Attachment) (err error) {
-	related := multipart.NewWriter(p)
-
-	_ = related.SetBoundary(message.GetRelatedBoundary(m))
-
-	buf := &bytes.Buffer{}
-	if err = im.writeMessageBody(buf, m); err != nil {
-		return
-	}
-
-	// Write the body part.
-	h := message.GetBodyHeader(m)
-
-	if p, err = related.CreatePart(h); err != nil {
-		return
-	}
-
-	_, _ = buf.WriteTo(p)
-
-	for _, inline := range inlines {
-		buf = &bytes.Buffer{}
-		if err = im.writeAttachmentBody(buf, m, inline); err != nil {
-			return
+		sort.Strings(fields)
+	} else { // add only requested (in requested order)
+		for _, f := range section.Fields {
+			fields = append(fields, textproto.CanonicalMIMEHeaderKey(f))
 		}
+	}
 
-		h := message.GetAttachmentHeader(inline)
-		if p, err = related.CreatePart(h); err != nil {
-			return
+	headerBuf := &bytes.Buffer{}
+	for _, canonical := range fields {
+		if values, ok := header[canonical]; !ok {
+			continue
+		} else {
+			for _, val := range values {
+				fmt.Fprintf(headerBuf, "%s: %s\r\n", canonical, val)
+			}
 		}
-		_, _ = buf.WriteTo(p)
 	}
-
-	_ = related.Close()
-	return nil
-}
-
-const (
-	noMultipart      = iota // only body
-	simpleMultipart         // body + attachment or inline
-	complexMultipart        // mixed, rfc822, alternatives, ...
-)
-
-func (im *imapMailbox) setMessageContentType(m *pmapi.Message) (multipartType int, err error) {
-	if m.MIMEType == "" {
-		err = fmt.Errorf("trying to set Content-Type without MIME TYPE")
-		return
-	}
-	// message.MIMEType can have just three values from our server:
-	// * `text/html` (refers to body type, but might contain attachments and inlines)
-	// * `text/plain` (refers to body type, but might contain attachments and inlines)
-	// * `multipart/mixed` (refers to external message with multipart structure)
-	// The proper header content fields must be set and saved to DB based MIMEType and content.
-	multipartType = noMultipart
-	if m.MIMEType == pmapi.ContentTypeMultipartMixed {
-		multipartType = complexMultipart
-	} else if m.NumAttachments != 0 {
-		multipartType = simpleMultipart
-	}
-
-	h := textproto.MIMEHeader(m.Header)
-	if multipartType == noMultipart {
-		message.SetBodyContentFields(&h, m)
-	} else {
-		h.Set("Content-Type",
-			fmt.Sprintf("%s; boundary=%s", "multipart/mixed", message.GetBoundary(m)),
-		)
-	}
-	m.Header = mail.Header(h)
-
-	return
+	return headerBuf.Bytes()
 }
 
 // buildMessage from PM to IMAP.
-func (im *imapMailbox) buildMessage(m *pmapi.Message) (structure *message.BodyStructure, msgBody []byte, err error) {
-	im.log.Trace("Building message")
-
-	var errNoCache doNotCacheError
-
-	// If fetch or decryption fails we need to change the MIMEType (in customMessage).
-	err = im.fetchMessage(m)
+func (im *imapMailbox) buildMessage(m *pmapi.Message) (*message.BodyStructure, []byte, error) {
+	body, err := im.builder.NewJobWithOptions(
+		context.Background(),
+		im.user.client(),
+		m.ID,
+		message.JobOptions{
+			IgnoreDecryptionErrors: true, // Whether to ignore decryption errors and create a "custom message" instead.
+			SanitizeDate:           true, // Whether to replace all dates before 1970 with RFC822's birthdate.
+			AddInternalID:          true, // Whether to include MessageID as X-Pm-Internal-Id.
+			AddExternalID:          true, // Whether to include ExternalID as X-Pm-External-Id.
+			AddMessageDate:         true, // Whether to include message time as X-Pm-Date.
+			AddMessageIDReference:  true, // Whether to include the MessageID in References.
+		},
+	).GetResult()
 	if err != nil {
-		return
-	}
-
-	kr, err := im.user.client().KeyRingForAddressID(m.AddressID)
-	if err != nil {
-		err = errors.Wrap(err, "failed to get keyring for address ID")
-		return
-	}
-
-	errDecrypt := m.Decrypt(kr)
-
-	if errDecrypt != nil && errDecrypt != openpgperrors.ErrSignatureExpired {
-		errNoCache.add(errDecrypt)
-		if customMessageErr := message.CustomMessage(m, errDecrypt, true); customMessageErr != nil {
-			im.log.WithError(customMessageErr).Warn("Failed to make custom message")
-		}
-	}
-
-	// Inner function can fail even when message is decrypted.
-	// #1048 For example we have problem with double-encrypted messages
-	// which seems as still encrypted and we try them to decrypt again
-	// and that fails. For any building error is better to return custom
-	// message than error because it will not be fixed and users would
-	// get error message all the time and could not see some messages.
-	structure, msgBody, err = im.buildMessageInner(m, kr)
-	if err == pmapi.ErrAPINotReachable || err == pmapi.ErrInvalidToken || err == pmapi.ErrUpgradeApplication {
 		return nil, nil, err
-	} else if err != nil {
-		errNoCache.add(err)
-		if customMessageErr := message.CustomMessage(m, err, true); customMessageErr != nil {
-			im.log.WithError(customMessageErr).Warn("Failed to make custom message")
-		}
-		structure, msgBody, err = im.buildMessageInner(m, kr)
-		if err != nil {
-			return nil, nil, err
-		}
 	}
 
-	err = errNoCache.errorOrNil()
-
-	return structure, msgBody, err
-}
-
-func (im *imapMailbox) buildMessageInner(m *pmapi.Message, kr *crypto.KeyRing) (structure *message.BodyStructure, msgBody []byte, err error) { // nolint[funlen]
-	multipartType, err := im.setMessageContentType(m)
+	structure, err := message.NewBodyStructure(bytes.NewReader(body))
 	if err != nil {
-		return
+		return nil, nil, err
 	}
 
-	tmpBuf := &bytes.Buffer{}
-	mainHeader := buildHeader(m)
-	if err = writeHeader(tmpBuf, mainHeader); err != nil {
-		return
-	}
-	_, _ = io.WriteString(tmpBuf, "\r\n")
-
-	switch multipartType {
-	case noMultipart:
-		err = message.WriteBody(tmpBuf, kr, m)
-		if err != nil {
-			return
-		}
-	case complexMultipart:
-		_, _ = io.WriteString(tmpBuf, "\r\n--"+message.GetBoundary(m)+"\r\n")
-		err = message.WriteBody(tmpBuf, kr, m)
-		if err != nil {
-			return
-		}
-		_, _ = io.WriteString(tmpBuf, "\r\n--"+message.GetBoundary(m)+"--\r\n")
-	case simpleMultipart:
-		atts, inlines := message.SeparateInlineAttachments(m)
-		mw := multipart.NewWriter(tmpBuf)
-		_ = mw.SetBoundary(message.GetBoundary(m))
-
-		var partWriter io.Writer
-
-		if len(inlines) > 0 {
-			relatedHeader := message.GetRelatedHeader(m)
-			if partWriter, err = mw.CreatePart(relatedHeader); err != nil {
-				return
-			}
-			_ = im.writeRelatedPart(partWriter, m, inlines)
-		} else {
-			buf := &bytes.Buffer{}
-			if err = im.writeMessageBody(buf, m); err != nil {
-				return
-			}
-
-			// Write the body part.
-			bodyHeader := message.GetBodyHeader(m)
-			if partWriter, err = mw.CreatePart(bodyHeader); err != nil {
-				return
-			}
-
-			_, _ = buf.WriteTo(partWriter)
-		}
-
-		// Write the attachments parts.
-		input := make([]interface{}, len(atts))
-		for i, att := range atts {
-			input[i] = att
-		}
-
-		processCallback := func(value interface{}) (interface{}, error) {
-			att := value.(*pmapi.Attachment)
-
-			buf := &bytes.Buffer{}
-			if err = im.writeAttachmentBody(buf, m, att); err != nil {
-				return nil, err
-			}
-			return buf, nil
-		}
-
-		collectCallback := func(idx int, value interface{}) error {
-			buf := value.(*bytes.Buffer)
-			defer buf.Reset()
-			att := atts[idx]
-
-			attachmentHeader := message.GetAttachmentHeader(att)
-			if partWriter, err = mw.CreatePart(attachmentHeader); err != nil {
-				return err
-			}
-
-			_, _ = buf.WriteTo(partWriter)
-			return nil
-		}
-
-		err = parallel.RunParallel(fetchAttachmentsWorkers, input, processCallback, collectCallback)
-		if err != nil {
-			return
-		}
-
-		_ = mw.Close()
-	default:
-		fmt.Fprintf(tmpBuf, "\r\n\r\nUknown multipart type: %d\r\n\r\n", multipartType)
-	}
-
-	// We need to copy buffer before building body structure.
-	msgBody = tmpBuf.Bytes()
-	structure, err = message.NewBodyStructure(tmpBuf)
-	if err != nil {
-		// NOTE: We need to set structure if it fails and is empty.
-		if structure == nil {
-			structure = &message.BodyStructure{}
-		}
-	}
-	return structure, msgBody, err
-}
-
-func buildHeader(msg *pmapi.Message) textproto.MIMEHeader {
-	header := message.GetHeader(msg)
-
-	msgTime := time.Unix(msg.Time, 0)
-
-	// Apple Mail crashes fetching messages with date older than 1970.
-	// There is no point having message older than RFC itself, it's not possible.
-	d, err := msg.Header.Date()
-	if err != nil || d.Before(rfc822Birthday) || msgTime.Before(rfc822Birthday) {
-		if err != nil || d.IsZero() {
-			header.Set("X-Original-Date", msgTime.Format(time.RFC1123Z))
-		} else {
-			header.Set("X-Original-Date", d.Format(time.RFC1123Z))
-		}
-		header.Set("Date", rfc822Birthday.Format(time.RFC1123Z))
-	}
-
-	return header
+	return structure, body, nil
 }

internal/imap/mailbox_messages.go

@@ -141,7 +141,7 @@ func (im *imapMailbox) addOrRemoveFlags(operation imap.FlagsOp, messageIDs, flag
 	for _, f := range flags {
 		switch f {
 		case imap.SeenFlag:
-			switch operation {
+			switch operation { //nolint[exhaustive] imap.SetFlags is processed by im.setFlags
 			case imap.AddFlags:
 				if err := im.storeMailbox.MarkMessagesRead(messageIDs); err != nil {
 					return err
@@ -152,7 +152,7 @@ func (im *imapMailbox) addOrRemoveFlags(operation imap.FlagsOp, messageIDs, flag
 				}
 			}
 		case imap.FlaggedFlag:
-			switch operation {
+			switch operation { //nolint[exhaustive] imap.SetFlag is processed by im.setFlags
 			case imap.AddFlags:
 				if err := im.storeMailbox.MarkMessagesStarred(messageIDs); err != nil {
 					return err
@@ -163,7 +163,7 @@ func (im *imapMailbox) addOrRemoveFlags(operation imap.FlagsOp, messageIDs, flag
 				}
 			}
 		case imap.DeletedFlag:
-			switch operation {
+			switch operation { //nolint[exhaustive] imap.SetFlag is processed by im.setFlags
 			case imap.AddFlags:
 				if err := im.storeMailbox.MarkMessagesDeleted(messageIDs); err != nil {
 					return err
@@ -182,7 +182,7 @@ func (im *imapMailbox) addOrRemoveFlags(operation imap.FlagsOp, messageIDs, flag
 			}
 
 			// Handle custom junk flags for Apple Mail and Thunderbird.
-			switch operation {
+			switch operation { //nolint[exhaustive] imap.SetFlag is processed by im.setFlags
 			// No label removal is necessary because Spam and Inbox are both exclusive labels so the backend
 			// will automatically take care of label removal.
 			case imap.AddFlags:
@@ -358,23 +358,29 @@ func (im *imapMailbox) SearchMessages(isUID bool, criteria *imap.SearchCriteria)
 				continue
 			}
 		}
+
+		// In order to speed up search it is not needed to check
+		// if IsFullHeaderCached.
+		header := storeMessage.GetHeader()
+
 		if !criteria.SentBefore.IsZero() || !criteria.SentSince.IsZero() {
-			if t, err := m.Header.Date(); err == nil && !t.IsZero() {
-				if !criteria.SentBefore.IsZero() {
-					if truncated := criteria.SentBefore.Truncate(24 * time.Hour); t.Unix() > truncated.Unix() {
-						continue
-					}
+			t, err := mail.Header(header).Date()
+			if err != nil || t.IsZero() {
+				t = time.Unix(m.Time, 0)
+			}
+			if !criteria.SentBefore.IsZero() {
+				if truncated := criteria.SentBefore.Truncate(24 * time.Hour); t.Unix() > truncated.Unix() {
+					continue
 				}
-				if !criteria.SentSince.IsZero() {
-					if truncated := criteria.SentSince.Truncate(24 * time.Hour); t.Unix() < truncated.Unix() {
-						continue
-					}
+			}
+			if !criteria.SentSince.IsZero() {
+				if truncated := criteria.SentSince.Truncate(24 * time.Hour); t.Unix() < truncated.Unix() {
+					continue
 				}
 			}
 		}
 
 		// Filter by headers.
-		header := message.GetHeader(m)
 		headerMatch := true
 		for criteriaKey, criteriaValues := range criteria.Header {
 			for _, criteriaValue := range criteriaValues {
@@ -382,6 +388,8 @@ func (im *imapMailbox) SearchMessages(isUID bool, criteria *imap.SearchCriteria)
 					continue
 				}
 				switch criteriaKey {
+				case "Subject":
+					headerMatch = strings.Contains(strings.ToLower(m.Subject), strings.ToLower(criteriaValue))
 				case "From":
 					headerMatch = addressMatch([]*mail.Address{m.Sender}, criteriaValue)
 				case "To":
@@ -482,12 +490,13 @@ func (im *imapMailbox) SearchMessages(isUID bool, criteria *imap.SearchCriteria)
 //
 // Messages must be sent to msgResponse. When the function returns, msgResponse must be closed.
 func (im *imapMailbox) ListMessages(isUID bool, seqSet *imap.SeqSet, items []imap.FetchItem, msgResponse chan<- *imap.Message) error {
+	msgBuildCountHistogram := newMsgBuildCountHistogram()
 	return im.logCommand(func() error {
-		return im.listMessages(isUID, seqSet, items, msgResponse)
-	}, "FETCH", isUID, seqSet, items)
+		return im.listMessages(isUID, seqSet, items, msgResponse, msgBuildCountHistogram)
+	}, "FETCH", isUID, seqSet, items, msgBuildCountHistogram)
 }
 
-func (im *imapMailbox) listMessages(isUID bool, seqSet *imap.SeqSet, items []imap.FetchItem, msgResponse chan<- *imap.Message) (err error) { //nolint[funlen]
+func (im *imapMailbox) listMessages(isUID bool, seqSet *imap.SeqSet, items []imap.FetchItem, msgResponse chan<- *imap.Message, msgBuildCountHistogram *msgBuildCountHistogram) (err error) { //nolint[funlen]
 	defer func() {
 		close(msgResponse)
 		if err != nil {
@@ -535,7 +544,7 @@ func (im *imapMailbox) listMessages(isUID bool, seqSet *imap.SeqSet, items []ima
 	}
 
 	processCallback := func(value interface{}) (interface{}, error) {
-		apiID := value.(string)
+		apiID := value.(string) //nolint[forcetypeassert] we want to panic here
 
 		storeMessage, err := im.storeMailbox.GetMessage(apiID)
 		if err != nil {
@@ -544,7 +553,7 @@ func (im *imapMailbox) listMessages(isUID bool, seqSet *imap.SeqSet, items []ima
 			return nil, err
 		}
 
-		msg, err := im.getMessage(storeMessage, items)
+		msg, err := im.getMessage(storeMessage, items, msgBuildCountHistogram)
 		if err != nil {
 			err = fmt.Errorf("list message build: %v", err)
 			l.WithField("metaID", storeMessage.ID()).Error(err)
@@ -569,12 +578,12 @@ func (im *imapMailbox) listMessages(isUID bool, seqSet *imap.SeqSet, items []ima
 	}
 
 	collectCallback := func(idx int, value interface{}) error {
-		msg := value.(*imap.Message)
+		msg := value.(*imap.Message) //nolint[forcetypeassert] we want to panic here
 		msgResponse <- msg
 		return nil
 	}
 
-	err = parallel.RunParallel(fetchMessagesWorkers, input, processCallback, collectCallback)
+	err = parallel.RunParallel(fetchWorkers, input, processCallback, collectCallback)
 	if err != nil {
 		return err
 	}

internal/imap/msg_build_counts.go

@@ -0,0 +1,65 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package imap
+
+import (
+	"fmt"
+	"sync"
+)
+
+// msgBuildCountHistogram is used to analyse and log the number of repetitive
+// downloads of requested messages per one fetch. The number of builds per each
+// messageID is stored in persistent database. The msgBuildCountHistogram will
+// take this number for each message in ongoing fetch and create histogram of
+// repeats.
+//
+// Example: During `fetch 1:300` there were
+// - 100 messages were downloaded first time
+// - 100 messages were downloaded second time
+// - 99 messages were downloaded 10th times
+// - 1 messages were downloaded 100th times.
+type msgBuildCountHistogram struct {
+	// Key represents how many times message was build.
+	// Value stores how many messages are build X times based on the key.
+	counts map[uint32]uint32
+	lock   sync.Locker
+}
+
+func newMsgBuildCountHistogram() *msgBuildCountHistogram {
+	return &msgBuildCountHistogram{
+		counts: map[uint32]uint32{},
+		lock:   &sync.Mutex{},
+	}
+}
+
+func (c *msgBuildCountHistogram) String() string {
+	res := ""
+	for nRebuild, counts := range c.counts {
+		if res != "" {
+			res += ", "
+		}
+		res += fmt.Sprintf("[%d]:%d", nRebuild, counts)
+	}
+	return res
+}
+
+func (c *msgBuildCountHistogram) add(nRebuild uint32) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.counts[nRebuild]++
+}

internal/imap/store.go

@@ -20,6 +20,7 @@ package imap
 import (
 	"io"
 	"net/mail"
+	"net/textproto"
 
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
 	"github.com/ProtonMail/proton-bridge/internal/imap/uidplus"
@@ -100,9 +101,12 @@ type storeMessageProvider interface {
 	IsMarkedDeleted() bool
 
 	SetSize(int64) error
-	SetContentTypeAndHeader(string, mail.Header) error
+	SetHeader([]byte) error
+	GetHeader() textproto.MIMEHeader
+	IsFullHeaderCached() bool
 	SetBodyStructure(*pkgMsg.BodyStructure) error
 	GetBodyStructure() (*pkgMsg.BodyStructure, error)
+	IncreaseBuildCount() (uint32, error)
 }
 
 type storeUserWrap struct {
@@ -122,7 +126,7 @@ func (s *storeUserWrap) GetAddress(addressID string) (storeAddressProvider, erro
 	if err != nil {
 		return nil, err
 	}
-	return newStoreAddressWrap(address), nil
+	return newStoreAddressWrap(address), nil //nolint[typecheck] missing methods are inherited
 }
 
 type storeAddressWrap struct {
@@ -136,7 +140,7 @@ func newStoreAddressWrap(address *store.Address) *storeAddressWrap {
 func (s *storeAddressWrap) ListMailboxes() []storeMailboxProvider {
 	mailboxes := []storeMailboxProvider{}
 	for _, mailbox := range s.Address.ListMailboxes() {
-		mailboxes = append(mailboxes, newStoreMailboxWrap(mailbox))
+		mailboxes = append(mailboxes, newStoreMailboxWrap(mailbox)) //nolint[typecheck] missing methods are inherited
 	}
 	return mailboxes
 }
@@ -146,7 +150,7 @@ func (s *storeAddressWrap) GetMailbox(name string) (storeMailboxProvider, error)
 	if err != nil {
 		return nil, err
 	}
-	return newStoreMailboxWrap(mailbox), nil
+	return newStoreMailboxWrap(mailbox), nil //nolint[typecheck] missing methods are inherited
 }
 
 type storeMailboxWrap struct {

internal/imap/uidplus/extension.go

@@ -33,7 +33,7 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-// Capability extension identifier
+// Capability extension identifier.
 const Capability = "UIDPLUS"
 
 const (
@@ -228,7 +228,9 @@ func getStatusResponseCopy(uidValidity uint32, sourceSeq, targetSeq *OrderedSeq)
 
 // CopyResponse prepares OK response with extended UID information about copied message.
 func CopyResponse(uidValidity uint32, sourceSeq, targetSeq *OrderedSeq) error {
-	return server.ErrStatusResp(getStatusResponseCopy(uidValidity, sourceSeq, targetSeq))
+	return &imap.ErrStatusResp{
+		Resp: getStatusResponseCopy(uidValidity, sourceSeq, targetSeq),
+	}
 }
 
 func getStatusResponseAppend(uidValidity uint32, targetSeq *OrderedSeq) *imap.StatusResp {
@@ -250,5 +252,7 @@ func getStatusResponseAppend(uidValidity uint32, targetSeq *OrderedSeq) *imap.St
 
 // AppendResponse prepares OK response with extended UID information about appended message.
 func AppendResponse(uidValidity uint32, targetSeq *OrderedSeq) error {
-	return server.ErrStatusResp(getStatusResponseAppend(uidValidity, targetSeq))
+	return &imap.ErrStatusResp{
+		Resp: getStatusResponseAppend(uidValidity, targetSeq),
+	}
 }

internal/imap/user.go

@@ -135,7 +135,7 @@ func (iu *imapUser) ListMailboxes(showOnlySubcribed bool) ([]goIMAPBackend.Mailb
 		if showOnlySubcribed && !iu.isSubscribed(storeMailbox.LabelID()) {
 			continue
 		}
-		mailbox := newIMAPMailbox(iu.panicHandler, iu, storeMailbox)
+		mailbox := newIMAPMailbox(iu.panicHandler, iu, storeMailbox, iu.backend.builder)
 		mailboxes = append(mailboxes, mailbox)
 	}
 
@@ -167,7 +167,7 @@ func (iu *imapUser) GetMailbox(name string) (mb goIMAPBackend.Mailbox, err error
 		return
 	}
 
-	return newIMAPMailbox(iu.panicHandler, iu, storeMailbox), nil
+	return newIMAPMailbox(iu.panicHandler, iu, storeMailbox, iu.backend.builder), nil
 }
 
 // CreateMailbox creates a new mailbox.

internal/importexport/importexport.go

@@ -88,7 +88,7 @@ func (ie *ImportExport) ReportBug(osType, osVersion, description, accountName, a
 	return nil
 }
 
-// ReportFile submits import report file
+// ReportFile submits import report file.
 func (ie *ImportExport) ReportFile(osType, osVersion, accountName, address string, logdata []byte) error {
 	c := ie.clientManager.GetAnonymousClient()
 	defer c.Logout()
@@ -118,9 +118,9 @@ func (ie *ImportExport) ReportFile(osType, osVersion, accountName, address strin
 }
 
 // GetLocalImporter returns transferrer from local EML or MBOX structure to ProtonMail account.
-func (ie *ImportExport) GetLocalImporter(address, path string) (*transfer.Transfer, error) {
+func (ie *ImportExport) GetLocalImporter(username, address, path string) (*transfer.Transfer, error) {
 	source := transfer.NewLocalProvider(path)
-	target, err := ie.getPMAPIProvider(address)
+	target, err := ie.getPMAPIProvider(username, address)
 	if err != nil {
 		return nil, err
 	}
@@ -132,12 +132,12 @@ func (ie *ImportExport) GetLocalImporter(address, path string) (*transfer.Transf
 }
 
 // GetRemoteImporter returns transferrer from remote IMAP to ProtonMail account.
-func (ie *ImportExport) GetRemoteImporter(address, username, password, host, port string) (*transfer.Transfer, error) {
-	source, err := transfer.NewIMAPProvider(username, password, host, port)
+func (ie *ImportExport) GetRemoteImporter(username, address, remoteUsername, remotePassword, host, port string) (*transfer.Transfer, error) {
+	source, err := transfer.NewIMAPProvider(remoteUsername, remotePassword, host, port)
 	if err != nil {
 		return nil, err
 	}
-	target, err := ie.getPMAPIProvider(address)
+	target, err := ie.getPMAPIProvider(username, address)
 	if err != nil {
 		return nil, err
 	}
@@ -149,8 +149,8 @@ func (ie *ImportExport) GetRemoteImporter(address, username, password, host, por
 }
 
 // GetEMLExporter returns transferrer from ProtonMail account to local EML structure.
-func (ie *ImportExport) GetEMLExporter(address, path string) (*transfer.Transfer, error) {
-	source, err := ie.getPMAPIProvider(address)
+func (ie *ImportExport) GetEMLExporter(username, address, path string) (*transfer.Transfer, error) {
+	source, err := ie.getPMAPIProvider(username, address)
 	if err != nil {
 		return nil, err
 	}
@@ -163,8 +163,8 @@ func (ie *ImportExport) GetEMLExporter(address, path string) (*transfer.Transfer
 }
 
 // GetMBOXExporter returns transferrer from ProtonMail account to local MBOX structure.
-func (ie *ImportExport) GetMBOXExporter(address, path string) (*transfer.Transfer, error) {
-	source, err := ie.getPMAPIProvider(address)
+func (ie *ImportExport) GetMBOXExporter(username, address, path string) (*transfer.Transfer, error) {
+	source, err := ie.getPMAPIProvider(username, address)
 	if err != nil {
 		return nil, err
 	}
@@ -176,8 +176,8 @@ func (ie *ImportExport) GetMBOXExporter(address, path string) (*transfer.Transfe
 	return transfer.New(ie.panicHandler, newExportMetricsManager(ie), logsPath, ie.cache.GetTransferDir(), source, target)
 }
 
-func (ie *ImportExport) getPMAPIProvider(address string) (*transfer.PMAPIProvider, error) {
-	user, err := ie.Users.GetUser(address)
+func (ie *ImportExport) getPMAPIProvider(username, address string) (*transfer.PMAPIProvider, error) {
+	user, err := ie.Users.GetUser(username)
 	if err != nil {
 		return nil, err
 	}

internal/locations/locations.go

@@ -32,9 +32,9 @@ import (
 // On linux:
 // - settings: ~/.config/protonmail/<app>
 // - logs: ~/.cache/protonmail/<app>/logs
-// - cache: ~/.cache/protonmail/<app>/cache
-// - updates: ~/.cache/protonmail/<app>/updates
-// - lockfile: ~/.cache/protonmail/<app>/<app>.lock
+// - cache: ~/.config/protonmail/<app>/cache
+// - updates: ~/.config/protonmail/<app>/updates
+// - lockfile: ~/.cache/protonmail/<app>/<app>.lock .
 type Locations struct {
 	userConfig, userCache string
 	configName            string
@@ -129,7 +129,7 @@ func (l *Locations) ProvideLogsPath() (string, error) {
 	return l.getLogsPath(), nil
 }
 
-// ProvideCachePath returns a location for user cache dirs (e.g. ~/.cache/<company>/<app>/cache).
+// ProvideCachePath returns a location for user cache dirs (e.g. ~/.config/<company>/<app>/cache).
 // It creates it if it doesn't already exist.
 func (l *Locations) ProvideCachePath() (string, error) {
 	if err := os.MkdirAll(l.getCachePath(), 0700); err != nil {
@@ -139,6 +139,11 @@ func (l *Locations) ProvideCachePath() (string, error) {
 	return l.getCachePath(), nil
 }
 
+// GetOldCachePath returns a former location for user cache dirs used for migration scripts only.
+func (l *Locations) GetOldCachePath() string {
+	return filepath.Join(l.userCache, "cache")
+}
+
 // ProvideUpdatesPath returns a location for update files (e.g. ~/.cache/<company>/<app>/updates).
 // It creates it if it doesn't already exist.
 func (l *Locations) ProvideUpdatesPath() (string, error) {
@@ -149,6 +154,16 @@ func (l *Locations) ProvideUpdatesPath() (string, error) {
 	return l.getUpdatesPath(), nil
 }
 
+// GetUpdatesPath returns a new location for update files used for migration scripts only.
+func (l *Locations) GetUpdatesPath() string {
+	return l.getUpdatesPath()
+}
+
+// GetOldUpdatesPath returns a former location for update files used for migration scripts only.
+func (l *Locations) GetOldUpdatesPath() string {
+	return filepath.Join(l.userCache, "updates")
+}
+
 func (l *Locations) getSettingsPath() string {
 	return l.userConfig
 }
@@ -158,11 +173,33 @@ func (l *Locations) getLogsPath() string {
 }
 
 func (l *Locations) getCachePath() string {
-	return filepath.Join(l.userCache, "cache")
+	// Bridge cache is not a typical cache which can be deleted with only
+	// downside that the app has to download everything again.
+	// Cache for bridge is database with IMAP UIDs and UIDVALIDITY, and also
+	// other IMAP setup. Deleting such data leads to either re-sync of client,
+	// or mix of headers and bodies. Both is caused because of need of re-sync
+	// between Bridge and API which will happen in different order than before.
+	// In the first case, UIDVALIDITY is also changed and causes the better
+	// outcome to "just" re-sync everything; in the later, UIDVALIDITY stays
+	// the same, causing the client to not re-sync but UIDs in the client does
+	// not match UIDs in Bridge.
+	// Because users might use tools to regularly clear caches, Bridge cache
+	// cannot be located in a standard cache folder.
+	return filepath.Join(l.userConfig, "cache")
 }
 
 func (l *Locations) getUpdatesPath() string {
-	return filepath.Join(l.userCache, "updates")
+	// In order to properly update Bridge 1.6.X and higher we need to
+	// change the launcher first. Since this is not part of automatic
+	// updates the migration must wait until manual update. Until that
+	// we need to keep old path.
+	if l.configName == "bridge" {
+		return l.GetOldUpdatesPath()
+	}
+
+	// Users might use tools to regularly clear caches, which would mean always
+	// removing updates, therefore Bridge updates have to be somewhere else.
+	return filepath.Join(l.userConfig, "updates")
 }
 
 // Clear removes everything except the lock and update files.

internal/locations/locations_test.go

@@ -45,7 +45,8 @@ func TestClearRemovesEverythingExceptLockAndUpdateFiles(t *testing.T) {
 	assert.NoError(t, l.Clear())
 
 	assert.FileExists(t, l.GetLockFile())
-	assert.NoDirExists(t, l.getSettingsPath())
+	assert.DirExists(t, l.getSettingsPath())
+	assert.NoFileExists(t, filepath.Join(l.getSettingsPath(), "prefs.json"))
 	assert.NoDirExists(t, l.getLogsPath())
 	assert.NoDirExists(t, l.getCachePath())
 	assert.DirExists(t, l.getUpdatesPath())
@@ -58,6 +59,7 @@ func TestClearUpdateFiles(t *testing.T) {
 
 	assert.FileExists(t, l.GetLockFile())
 	assert.DirExists(t, l.getSettingsPath())
+	assert.FileExists(t, filepath.Join(l.getSettingsPath(), "prefs.json"))
 	assert.DirExists(t, l.getLogsPath())
 	assert.DirExists(t, l.getCachePath())
 	assert.NoDirExists(t, l.getUpdatesPath())
@@ -75,6 +77,7 @@ func TestCleanLeavesStandardLocationsUntouched(t *testing.T) {
 
 	assert.FileExists(t, l.GetLockFile())
 	assert.DirExists(t, l.getSettingsPath())
+	assert.FileExists(t, filepath.Join(l.getSettingsPath(), "prefs.json"))
 	assert.DirExists(t, l.getLogsPath())
 	assert.FileExists(t, filepath.Join(l.getLogsPath(), "log1.txt"))
 	assert.FileExists(t, filepath.Join(l.getLogsPath(), "log2.txt"))
@@ -138,6 +141,9 @@ func newTestLocations(t *testing.T) *Locations {
 	require.NoError(t, err)
 	require.DirExists(t, settings)
 
+	createFilesInDir(t, settings, "prefs.json")
+	require.FileExists(t, filepath.Join(settings, "prefs.json"))
+
 	logs, err := l.ProvideLogsPath()
 	require.NoError(t, err)
 	require.DirExists(t, logs)

internal/logging/crash.go

@@ -34,7 +34,7 @@ func DumpStackTrace(logsPath string) crash.RecoveryAction {
 	return func(r interface{}) error {
 		file := filepath.Join(logsPath, getStackTraceName(constants.Version, constants.Revision))
 
-		f, err := os.OpenFile(file, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0600)
+		f, err := os.OpenFile(filepath.Clean(file), os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0600)
 		if err != nil {
 			return err
 		}

internal/logging/logging.go

@@ -42,6 +42,7 @@ const (
 
 func Init(logsPath string) error {
 	logrus.SetFormatter(&logrus.TextFormatter{
+		ForceColors:     true,
 		FullTimestamp:   true,
 		TimestampFormat: time.StampMilli,
 	})
@@ -69,6 +70,10 @@ func Init(logsPath string) error {
 	return nil
 }
 
+// SetLevel will change the level of logging and in case of Debug or Trace
+// level it will also prevent from writing to file. Setting level to Info or
+// higher will not set writing to file again if it was previously cancelled by
+// Debug or Trace.
 func SetLevel(level string) {
 	if lvl, err := logrus.ParseLevel(level); err == nil {
 		logrus.SetLevel(lvl)

internal/smtp/bridge.go

@@ -51,7 +51,7 @@ func (b *bridgeWrap) GetUser(query string) (bridgeUser, error) {
 	if err != nil {
 		return nil, err
 	}
-	return newBridgeUserWrap(user), nil
+	return newBridgeUserWrap(user), nil //nolint[typecheck] missing methods are inherited
 }
 
 type bridgeUserWrap struct {

internal/smtp/preferences.go

@@ -173,7 +173,7 @@ func (b *sendPreferencesBuilder) withPublicKey(v *crypto.KeyRing) {
 //								| 16 (PGP/MIME),
 //     mimeType: 'text/html' | 'text/plain' | 'multipart/mixed',
 //     publicKey: OpenPGPKey | undefined/null
-// }
+// }.
 func (b *sendPreferencesBuilder) build() (p SendPreferences) {
 	p.Encrypt = b.shouldEncrypt()
 	p.Sign = b.shouldSign()
@@ -492,6 +492,8 @@ func (b *sendPreferencesBuilder) setEncryptionPreferences(mailSettings pmapi.Mai
 		b.withSchemeDefault(pgpInline)
 	case pmapi.PGPMIMEPackage:
 		b.withSchemeDefault(pgpMIME)
+	case pmapi.ClearMIMEPackage, pmapi.ClearPackage, pmapi.EncryptedOutsidePackage, pmapi.InternalPackage:
+		// nothing to set
 	}
 
 	// Its value is constrained by the sign flag and the PGP scheme:

internal/smtp/server.go

@@ -42,6 +42,7 @@ func NewSMTPServer(debug bool, port int, useSSL bool, tls *tls.Config, smtpBacke
 	s.TLSConfig = tls
 	s.Domain = bridge.Host
 	s.AllowInsecureAuth = true
+	s.MaxLineLength = 2 << 16
 
 	if debug {
 		fmt.Println("THE LOG WILL CONTAIN **DECRYPTED** MESSAGE DATA")

internal/store/event_loop.go

@@ -156,6 +156,7 @@ func (loop *eventLoop) loop() {
 			return
 		case <-t.C:
 			// Randomise periodic calls within range pollInterval ± pollSpread to reduces potential load spikes on API.
+			//nolint[gosec] It is OK to use weaker random number generator here
 			time.Sleep(time.Duration(rand.Intn(2*int(pollIntervalSpread.Milliseconds()))) * time.Millisecond)
 		case eventProcessedCh = <-loop.pollCh:
 			// We don't want to wait here. Polling should happen instantly.
@@ -268,8 +269,6 @@ func (loop *eventLoop) processNextEvent() (more bool, err error) { // nolint[fun
 		return false, errors.New("received empty event")
 	}
 
-	l = l.WithField("newEventID", event.EventID)
-
 	if err = loop.processEvent(event); err != nil {
 		return false, errors.Wrap(err, "failed to process event")
 	}
@@ -383,6 +382,8 @@ func (loop *eventLoop) processAddresses(log *logrus.Entry, addressEvents []*pmap
 			log.WithField("email", email).Debug("Address was deleted")
 			loop.user.CloseConnection(email)
 			loop.events.Emit(bridgeEvents.AddressChangedLogoutEvent, email)
+		case pmapi.EventUpdateFlags:
+			log.Error("EventUpdateFlags for address event is uknown operation")
 		}
 	}
 
@@ -411,6 +412,8 @@ func (loop *eventLoop) processLabels(eventLog *logrus.Entry, labels []*pmapi.Eve
 			if err := loop.store.deleteMailboxEvent(eventLabel.ID); err != nil {
 				return errors.Wrap(err, "failed to delete label")
 			}
+		case pmapi.EventUpdateFlags:
+			log.Error("EventUpdateFlags for label event is uknown operation")
 		}
 	}
 

internal/store/mailbox.go

@@ -254,7 +254,7 @@ func (storeMailbox *Mailbox) txGetAPIIDsBucket(tx *bolt.Tx) *bolt.Bucket {
 	return storeMailbox.txGetBucket(tx).Bucket(apiIDsBucket)
 }
 
-// txGetDeletedIDsBucket returns the bucket with messagesID marked as deleted
+// txGetDeletedIDsBucket returns the bucket with messagesID marked as deleted.
 func (storeMailbox *Mailbox) txGetDeletedIDsBucket(tx *bolt.Tx) *bolt.Bucket {
 	return storeMailbox.txGetBucket(tx).Bucket(deletedIDsBucket)
 }

internal/store/mailbox_message.go

@@ -25,7 +25,7 @@ import (
 )
 
 // ErrAllMailOpNotAllowed is error user when user tries to do unsupported
-// operation on All Mail folder
+// operation on All Mail folder.
 var ErrAllMailOpNotAllowed = errors.New("operation not allowed for 'All Mail' folder")
 
 // GetMessage returns the `pmapi.Message` struct wrapped in `StoreMessage`
@@ -67,10 +67,14 @@ func (storeMailbox *Mailbox) ImportMessage(msg *pmapi.Message, body []byte, labe
 	}
 
 	res, err := storeMailbox.client().Import([]*pmapi.ImportMsgReq{importReqs})
-	if err == nil && len(res) > 0 {
-		msg.ID = res[0].MessageID
+	if err != nil {
+		return err
 	}
-	return err
+	if len(res) == 0 {
+		return errors.New("no import response")
+	}
+	msg.ID = res[0].MessageID
+	return res[0].Error
 }
 
 // LabelMessages adds the label by calling an API.
@@ -173,7 +177,7 @@ func (storeMailbox *Mailbox) MarkMessagesUnstarred(apiIDs []string) error {
 }
 
 // MarkMessagesDeleted adds local flag \Deleted. This is not propagated to API
-// until RemoveDeleted is called
+// until RemoveDeleted is called.
 func (storeMailbox *Mailbox) MarkMessagesDeleted(apiIDs []string) error {
 	log.WithFields(logrus.Fields{
 		"messages": apiIDs,

internal/store/message.go

@@ -18,7 +18,10 @@
 package store
 
 import (
+	"bufio"
+	"bytes"
 	"net/mail"
+	"net/textproto"
 
 	pkgMsg "github.com/ProtonMail/proton-bridge/pkg/message"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
@@ -64,7 +67,7 @@ func (message *Message) Message() *pmapi.Message {
 }
 
 // IsMarkedDeleted returns true if message is marked as deleted for specific
-// mailbox
+// mailbox.
 func (message *Message) IsMarkedDeleted() bool {
 	isMarkedAsDeleted := false
 	err := message.storeMailbox.db().View(func(tx *bolt.Tx) error {
@@ -103,6 +106,8 @@ func (message *Message) SetSize(size int64) error {
 // header of decrypted message. This should not trigger any IMAP update.
 // NOTE: Content type depends on details of decrypted message which we want to
 // cache.
+//
+// Deprecated: Use SetHeader instead.
 func (message *Message) SetContentTypeAndHeader(mimeType string, header mail.Header) error {
 	message.msg.MIMEType = mimeType
 	message.msg.Header = header
@@ -121,6 +126,45 @@ func (message *Message) SetContentTypeAndHeader(mimeType string, header mail.Hea
 	return message.store.db.Update(txUpdate)
 }
 
+// SetHeader checks header can be parsed and if yes it stores header bytes in
+// database.
+func (message *Message) SetHeader(header []byte) error {
+	_, err := textproto.NewReader(bufio.NewReader(bytes.NewReader(header))).ReadMIMEHeader()
+	if err != nil {
+		return err
+	}
+	return message.store.db.Update(func(tx *bolt.Tx) error {
+		return tx.Bucket(headersBucket).Put([]byte(message.ID()), header)
+	})
+}
+
+// IsFullHeaderCached will check that valid full header is stored in DB.
+func (message *Message) IsFullHeaderCached() bool {
+	header, err := message.getRawHeader()
+	return err == nil && header != nil
+}
+
+func (message *Message) getRawHeader() (raw []byte, err error) {
+	err = message.store.db.View(func(tx *bolt.Tx) error {
+		raw = tx.Bucket(headersBucket).Get([]byte(message.ID()))
+		return nil
+	})
+	return
+}
+
+// GetHeader will return cached header from DB.
+func (message *Message) GetHeader() textproto.MIMEHeader {
+	raw, err := message.getRawHeader()
+	if err != nil && raw == nil {
+		return textproto.MIMEHeader(message.msg.Header)
+	}
+	header, err := textproto.NewReader(bufio.NewReader(bytes.NewReader(raw))).ReadMIMEHeader()
+	if err != nil {
+		return textproto.MIMEHeader(message.msg.Header)
+	}
+	return header
+}
+
 // SetBodyStructure stores serialized body structure in database.
 func (message *Message) SetBodyStructure(bs *pkgMsg.BodyStructure) error {
 	txUpdate := func(tx *bolt.Tx) error {
@@ -148,3 +192,17 @@ func (message *Message) GetBodyStructure() (bs *pkgMsg.BodyStructure, err error)
 	}
 	return bs, nil
 }
+
+func (message *Message) IncreaseBuildCount() (times uint32, err error) {
+	txUpdate := func(tx *bolt.Tx) error {
+		times, err = message.store.txIncreaseMsgBuildCount(
+			tx.Bucket(msgBuildCountBucket),
+			message.ID(),
+		)
+		return err
+	}
+	if err = message.store.db.Update(txUpdate); err != nil {
+		return 0, err
+	}
+	return times, nil
+}

internal/store/store.go

@@ -34,15 +34,15 @@ import (
 )
 
 const (
-	// PathDelimiter for IMAP
+	// PathDelimiter for IMAP.
 	PathDelimiter = "/"
-	// UserLabelsMailboxName for IMAP
+	// UserLabelsMailboxName for IMAP.
 	UserLabelsMailboxName = "Labels"
-	// UserLabelsPrefix contains name with delimiter for IMAP
+	// UserLabelsPrefix contains name with delimiter for IMAP.
 	UserLabelsPrefix = UserLabelsMailboxName + PathDelimiter
-	// UserFoldersMailboxName for IMAP
+	// UserFoldersMailboxName for IMAP.
 	UserFoldersMailboxName = "Folders"
-	// UserFoldersPrefix contains name with delimiter for IMAP
+	// UserFoldersPrefix contains name with delimiter for IMAP.
 	UserFoldersPrefix = UserFoldersMailboxName + PathDelimiter
 )
 
@@ -51,9 +51,13 @@ var (
 
 	// Database structure:
 	// * metadata
-	//   * {messageID} -> message data (subject, from, to, time, headers, body size, ...)
+	//   * {messageID} -> message data (subject, from, to, time, body size, ...)
+	// * headers
+	//   * {messageID} -> header bytes
 	// * bodystructure
 	//   * {messageID} -> message body structure
+	// * msgbuildcount
+	//   * {messageID} -> uint32 number of message builds to track re-sync issues
 	// * counts
 	//   * {mailboxID} -> mailboxCounts: totalOnAPI, unreadOnAPI, labelName, labelColor, labelIsExclusive
 	// * address_info
@@ -75,7 +79,9 @@ var (
 	//     * deleted_ids (can be missing or have no keys)
 	//       * {messageID} -> true
 	metadataBucket      = []byte("metadata")          //nolint[gochecknoglobals]
+	headersBucket       = []byte("headers")           //nolint[gochecknoglobals]
 	bodystructureBucket = []byte("bodystructure")     //nolint[gochecknoglobals]
+	msgBuildCountBucket = []byte("msgbuildcount")     //nolint[gochecknoglobals]
 	countsBucket        = []byte("counts")            //nolint[gochecknoglobals]
 	addressInfoBucket   = []byte("address_info")      //nolint[gochecknoglobals]
 	addressModeBucket   = []byte("address_mode")      //nolint[gochecknoglobals]
@@ -196,36 +202,24 @@ func openBoltDatabase(filePath string) (db *bolt.DB, err error) {
 	}
 
 	tx := func(tx *bolt.Tx) (err error) {
-		if _, err = tx.CreateBucketIfNotExists(metadataBucket); err != nil {
-			return
+		buckets := [][]byte{
+			metadataBucket,
+			headersBucket,
+			bodystructureBucket,
+			msgBuildCountBucket,
+			countsBucket,
+			addressInfoBucket,
+			addressModeBucket,
+			syncStateBucket,
+			mailboxesBucket,
+			mboxVersionBucket,
 		}
 
-		if _, err = tx.CreateBucketIfNotExists(bodystructureBucket); err != nil {
-			return
-		}
-
-		if _, err = tx.CreateBucketIfNotExists(countsBucket); err != nil {
-			return
-		}
-
-		if _, err = tx.CreateBucketIfNotExists(addressInfoBucket); err != nil {
-			return
-		}
-
-		if _, err = tx.CreateBucketIfNotExists(addressModeBucket); err != nil {
-			return
-		}
-
-		if _, err = tx.CreateBucketIfNotExists(syncStateBucket); err != nil {
-			return
-		}
-
-		if _, err = tx.CreateBucketIfNotExists(mailboxesBucket); err != nil {
-			return
-		}
-
-		if _, err = tx.CreateBucketIfNotExists(mboxVersionBucket); err != nil {
-			return
+		for _, bucket := range buckets {
+			if _, err = tx.CreateBucketIfNotExists(bucket); err != nil {
+				err = errors.Wrap(err, string(bucket))
+				return
+			}
 		}
 
 		return
@@ -263,7 +257,7 @@ func (store *Store) init(firstInit bool) (err error) {
 		}
 	}
 
-	store.log.WithField("mode", store.addressMode).Debug("Initialising store")
+	store.log.WithField("mode", store.addressMode).Info("Initialising store")
 
 	labels, err := store.initCounts()
 	if err != nil {

internal/store/store_test_exports.go

@@ -90,10 +90,7 @@ func (store *Store) TestDumpDB(tb assert.TestingT) {
 				return err
 			}
 		}
-		if err := txMails(tx); err != nil {
-			return err
-		}
-		return nil
+		return txMails(tx)
 	}
 
 	assert.NoError(tb, store.db.View(txDump))

internal/store/user_message.go

@@ -191,6 +191,19 @@ func (store *Store) txGetBodyStructure(bsBucket *bolt.Bucket, msgID string) (*pk
 	return pkgMsg.DeserializeBodyStructure(raw)
 }
 
+func (store *Store) txIncreaseMsgBuildCount(b *bolt.Bucket, msgID string) (uint32, error) {
+	key := []byte(msgID)
+	count := uint32(0)
+
+	raw := b.Get(key)
+	if raw != nil {
+		count = btoi(raw)
+	}
+
+	count++
+	return count, b.Put(key, itob(count))
+}
+
 // createOrUpdateMessageEvent is helper to create only one message with
 // createOrUpdateMessagesEvent.
 func (store *Store) createOrUpdateMessageEvent(msg *pmapi.Message) error {
@@ -276,7 +289,7 @@ func clearNonMetadata(onlyMeta *pmapi.Message) {
 // If there is stored message in metaBucket the size, header and MIMEType are
 // not changed if already set. To change these:
 // * size must be updated by Message.SetSize
-// * contentType and header must be updated by Message.SetContentTypeAndHeader
+// * contentType and header must be updated by Message.SetContentTypeAndHeader.
 func txUpdateMetadaFromDB(metaBucket *bolt.Bucket, onlyMeta *pmapi.Message, log *logrus.Entry) {
 	// Size attribute on the server is counting encrypted data. We need to compute
 	// "real" size of decrypted data. Negative values will be processed during fetch.

internal/transfer/mailbox.go

@@ -35,7 +35,7 @@ var systemFolderMapping = map[string]string{ //nolint[gochecknoglobals]
 	// Add more translations.
 }
 
-// LeastUsedColor is intended to return color for creating a new inbox or label
+// LeastUsedColor is intended to return color for creating a new inbox or label.
 func LeastUsedColor(mailboxes []Mailbox) string {
 	usedColors := []string{}
 	for _, m := range mailboxes {

internal/transfer/provider_imap.go

@@ -27,7 +27,7 @@ import (
 
 type IMAPClientProvider interface {
 	Capability() (map[string]bool, error)
-	Support(cap string) (bool, error)
+	Support(capability string) (bool, error)
 	State() imap.ConnState
 	SupportAuth(mech string) (bool, error)
 	Authenticate(auth sasl.Client) error

internal/transfer/provider_imap_utils.go

@@ -62,10 +62,10 @@ func imapClientDial(addr string) (IMAPClientProvider, error) {
 		client.ErrorLog = &imapErrorLogger{logrus.WithField("pkg", "imap-client")}
 		// Logrus `WriterLevel` fails for big messages because of bufio.MaxScanTokenSize limit.
 		// Also, this spams a lot, uncomment once needed during development.
-		//client.SetDebug(imap.NewDebugWriter(
+		// client.SetDebug(imap.NewDebugWriter(
 		//	logrus.WithField("pkg", "imap/client").WriterLevel(logrus.TraceLevel),
 		//	logrus.WithField("pkg", "imap/server").WriterLevel(logrus.TraceLevel),
-		//))
+		// ))
 	}
 	return client, err
 }
@@ -84,7 +84,7 @@ func imapClientDialHelper(addr string) (*imapClient.Client, error) {
 	var tlsConf *tls.Config
 	if strings.Contains(strings.ToLower(host), "yahoo") {
 		log.Warning("Yahoo server detected: limiting maximal TLS version to 1.2.")
-		tlsConf = &tls.Config{MaxVersion: tls.VersionTLS12}
+		tlsConf = &tls.Config{MaxVersion: tls.VersionTLS12} //nolint[gosec] G402
 	}
 	return imapClient.DialTLS(addr, tlsConf)
 }

internal/transfer/provider_mbox_target.go

@@ -63,7 +63,7 @@ func (p *MBOXProvider) writeMessage(msg Message) error {
 		}
 
 		mboxPath := filepath.Join(p.root, mboxName)
-		mboxFile, err := os.OpenFile(mboxPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
+		mboxFile, err := os.OpenFile(filepath.Clean(mboxPath), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
 		if err != nil {
 			multiErr = multierror.Append(multiErr, err)
 			continue

internal/transfer/provider_pmapi.go

@@ -21,16 +21,24 @@ import (
 	"sort"
 
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/ProtonMail/proton-bridge/pkg/message"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 	"github.com/pkg/errors"
 )
 
+const (
+	fetchWorkers  = 20 // In how many workers to fetch message (group list on IMAP).
+	attachWorkers = 5  // In how many workers to fetch attachments (for one message).
+	buildWorkers  = 20 // In how many workers to build messages.
+)
+
 // PMAPIProvider implements import and export to/from ProtonMail server.
 type PMAPIProvider struct {
 	clientManager ClientManager
 	userID        string
 	addressID     string
 	keyRing       *crypto.KeyRing
+	builder       *message.Builder
 
 	nextImportRequests     map[string]*pmapi.ImportMsgReq // Key is msg transfer ID.
 	nextImportRequestsSize int
@@ -44,6 +52,7 @@ func NewPMAPIProvider(clientManager ClientManager, userID, addressID string) (*P
 		clientManager: clientManager,
 		userID:        userID,
 		addressID:     addressID,
+		builder:       message.NewBuilder(fetchWorkers, attachWorkers, buildWorkers),
 
 		nextImportRequests:     map[string]*pmapi.ImportMsgReq{},
 		nextImportRequestsSize: 0,

internal/transfer/provider_pmapi_source.go

@@ -18,12 +18,13 @@
 package transfer
 
 import (
+	"context"
+	"errors"
 	"fmt"
 	"sync"
 
-	pkgMsg "github.com/ProtonMail/proton-bridge/pkg/message"
+	"github.com/ProtonMail/proton-bridge/pkg/message"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
-	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
@@ -144,6 +145,7 @@ func (p *PMAPIProvider) transferTo(rule *Rule, progress *Progress, ch chan<- Mes
 
 func (p *PMAPIProvider) exportMessage(rule *Rule, progress *Progress, pmapiMsgID, msgID string, skipEncryptedMessages bool) (Message, error) {
 	var msg *pmapi.Message
+
 	progress.callWrap(func() error {
 		var err error
 		msg, err = p.getMessage(pmapiMsgID)
@@ -153,19 +155,18 @@ func (p *PMAPIProvider) exportMessage(rule *Rule, progress *Progress, pmapiMsgID
 	p.timeIt.start("build", msgID)
 	defer p.timeIt.stop("build", msgID)
 
-	msgBuilder := pkgMsg.NewBuilder(p.client(), msg)
-	msgBuilder.EncryptedToHTML = false
-	_, body, err := msgBuilder.BuildMessage()
+	body, err := p.builder.NewJobWithOptions(
+		context.Background(),
+		p.client(),
+		msg.ID,
+		message.JobOptions{IgnoreDecryptionErrors: !skipEncryptedMessages},
+	).GetResult()
 	if err != nil {
-		return Message{
-			Body: body, // Keep body to show details about the message to user.
-		}, errors.Wrap(err, "failed to build message")
-	}
+		if errors.Is(err, message.ErrDecryptionFailed) && skipEncryptedMessages {
+			err = errors.New("skipping encrypted message")
+		}
 
-	if !msgBuilder.SuccessfullyDecrypted() && skipEncryptedMessages {
-		return Message{
-			Body: body, // Keep body to show details about the message to user.
-		}, errors.New("skipping encrypted message")
+		return Message{Body: []byte(msg.Body)}, err
 	}
 
 	unread := false

internal/transfer/provider_pmapi_target.go

@@ -329,10 +329,10 @@ func (p *PMAPIProvider) importMessage(msgSourceID string, progress *Progress, re
 		}
 		if results[0].Error != nil {
 			importedErr = errors.Wrap(results[0].Error, "failed to import message")
-			return nil // Call passed but API refused this message, skip this one.
+			return nil //nolint[nilerr] Call passed but API refused this message, skip this one.
 		}
 		importedID = results[0].MessageID
 		return nil
 	})
-	return
+	return importedID, importedErr
 }

internal/transfer/provider_test.go

@@ -85,7 +85,7 @@ func testTransferFrom(t *testing.T, rules transferRules, provider TargetProvider
 		progress.finish()
 	}()
 
-	maxWait := time.Duration(len(messages)) * 2 * time.Second
+	maxWait := time.Duration(len(messages)*2) * time.Second
 	a.Eventually(t, func() bool {
 		return progress.updateCh == nil
 	}, maxWait, 10*time.Millisecond, "Waiting for imported messages timed out")

internal/updater/sync.go

@@ -125,7 +125,7 @@ func mkdirAllClear(path string) error {
 
 // checksum assumes the file is a regular file and that it exists.
 func checksum(path string) (hash string) {
-	file, err := os.Open(path) //nolint[gosec]
+	file, err := os.Open(filepath.Clean(path))
 	if err != nil {
 		return
 	}
@@ -224,7 +224,7 @@ func copyRecursively(srcDir, dstDir string) error { // nolint[funlen]
 		}
 
 		// Create/overwrite regular file.
-		srcReader, err := os.Open(srcPath) //nolint[gosec]
+		srcReader, err := os.Open(filepath.Clean(srcPath))
 		if err != nil {
 			return err
 		}
@@ -244,7 +244,7 @@ func copyToTmpFileRename(srcReader io.Reader, dstPath string, dstMode os.FileMod
 
 func copyToFileTruncate(srcReader io.Reader, dstPath string, dstMode os.FileMode) error {
 	logrus.Debug("Copy and truncate ", dstPath)
-	dstWriter, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, dstMode)
+	dstWriter, err := os.OpenFile(filepath.Clean(dstPath), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, dstMode) //nolint[gosec] Cannot guess the safe part of path
 	if err != nil {
 		return err
 	}

internal/updater/version.go

@@ -78,7 +78,7 @@ type VersionInfo struct {
 //   "...": {
 //     ...
 //   }
-// }
+// }.
 type VersionMap map[string]VersionInfo
 
 // getVersionFileURL returns the URL of the version file.

internal/users/credentials/store_test.go

@@ -67,7 +67,7 @@ func (s *testCredentials) MarshalGob() string {
 	if err := enc.Encode(s); err != nil {
 		return ""
 	}
-	fmt.Printf("MarshalGob: %#v\n", buf.String())
+	log.Infof("MarshalGob: %#v\n", buf.String())
 	return base64.StdEncoding.EncodeToString(buf.Bytes())
 }
 
@@ -88,13 +88,13 @@ func (s *testCredentials) UnmarshalGob(secret string) error {
 	s.Clear()
 	b, err := base64.StdEncoding.DecodeString(secret)
 	if err != nil {
-		fmt.Println("decode base64", b)
+		log.Infoln("decode base64", b)
 		return err
 	}
 	buf := bytes.NewBuffer(b)
 	dec := gob.NewDecoder(buf)
 	if err = dec.Decode(s); err != nil {
-		fmt.Println("decode gob", b, buf.Bytes())
+		log.Info("decode gob", b, buf.Bytes())
 		return err
 	}
 	return nil
@@ -102,7 +102,7 @@ func (s *testCredentials) UnmarshalGob(secret string) error {
 
 func (s *testCredentials) ToJSON() string {
 	if b, err := json.Marshal(s); err == nil {
-		fmt.Printf("MarshalJSON: %#v\n", string(b))
+		log.Infof("MarshalJSON: %#v\n", string(b))
 		return base64.StdEncoding.EncodeToString(b)
 	}
 	return ""
@@ -134,7 +134,7 @@ func (s *testCredentials) MarshalFmt() string {
 		s.IsHidden,
 		s.IsCombinedAddressMode,
 	)
-	fmt.Printf("MarshalFmt: %#v\n", buf.String())
+	log.Infof("MarshalFmt: %#v\n", buf.String())
 	return base64.StdEncoding.EncodeToString(buf.Bytes())
 }
 
@@ -144,7 +144,7 @@ func (s *testCredentials) UnmarshalFmt(secret string) error {
 		return err
 	}
 	buf := bytes.NewBuffer(b)
-	fmt.Println("decode fmt", b, buf.Bytes())
+	log.Infoln("decode fmt", b, buf.Bytes())
 	_, err = fmt.Fscanf(
 		buf, secretFormat,
 		&s.UserID,
@@ -190,7 +190,7 @@ func (s *testCredentials) MarshalStrings() string { // this is the most space ef
 
 	str := strings.Join(items, sep)
 
-	fmt.Printf("MarshalJoin: %#v\n", str)
+	log.Infof("MarshalJoin: %#v\n", str)
 	return base64.StdEncoding.EncodeToString([]byte(str))
 }
 
@@ -237,37 +237,37 @@ func (s *testCredentials) IsSame(rhs *testCredentials) bool {
 
 func TestMarshalFormats(t *testing.T) {
 	input := testCredentials{UserID: "007", Emails: "ja@pm.me;jakub@cu.th", Timestamp: 152469263742, IsHidden: true}
-	fmt.Printf("input %#v\n", input)
+	log.Infof("input %#v\n", input)
 
 	secretStrings := input.MarshalStrings()
-	fmt.Printf("secretStrings %#v %d\n", secretStrings, len(secretStrings))
+	log.Infof("secretStrings %#v %d\n", secretStrings, len(secretStrings))
 	secretGob := input.MarshalGob()
-	fmt.Printf("secretGob %#v %d\n", secretGob, len(secretGob))
+	log.Infof("secretGob %#v %d\n", secretGob, len(secretGob))
 	secretJSON := input.ToJSON()
-	fmt.Printf("secretJSON %#v %d\n", secretJSON, len(secretJSON))
+	log.Infof("secretJSON %#v %d\n", secretJSON, len(secretJSON))
 	secretFmt := input.MarshalFmt()
-	fmt.Printf("secretFmt %#v %d\n", secretFmt, len(secretFmt))
+	log.Infof("secretFmt %#v %d\n", secretFmt, len(secretFmt))
 
 	output := testCredentials{APIToken: "refresh"}
 	require.NoError(t, output.UnmarshalStrings(secretStrings))
-	fmt.Printf("strings out %#v \n", output)
+	log.Infof("strings out %#v \n", output)
 	require.True(t, input.IsSame(&output), "strings out not same")
 
 	output = testCredentials{APIToken: "refresh"}
 	require.NoError(t, output.UnmarshalGob(secretGob))
-	fmt.Printf("gob out %#v\n \n", output)
+	log.Infof("gob out %#v\n \n", output)
 	assert.Equal(t, input, output)
 
 	output = testCredentials{APIToken: "refresh"}
 	require.NoError(t, output.FromJSON(secretJSON))
-	fmt.Printf("json out %#v \n", output)
+	log.Infof("json out %#v \n", output)
 	require.True(t, input.IsSame(&output), "json out not same")
 
 	/*
 		// Simple Fscanf not working!
 		output = testCredentials{APIToken: "refresh"}
 			require.NoError(t, output.UnmarshalFmt(secretFmt))
-			fmt.Printf("fmt out %#v \n", output)
+			log.Infof("fmt out %#v \n", output)
 			require.True(t, input.IsSame(&output), "fmt out not same")
 	*/
 }
@@ -285,13 +285,13 @@ func TestMarshal(t *testing.T) {
 		IsHidden:              true,
 		IsCombinedAddressMode: false,
 	}
-	fmt.Printf("input %#v\n", input)
+	log.Infof("input %#v\n", input)
 
 	secret := input.Marshal()
-	fmt.Printf("secret %#v %d\n", secret, len(secret))
+	log.Infof("secret %#v %d\n", secret, len(secret))
 
 	output := Credentials{APIToken: "refresh"}
 	require.NoError(t, output.Unmarshal(secret))
-	fmt.Printf("output %#v\n", output)
+	log.Infof("output %#v\n", output)
 	assert.Equal(t, input, output)
 }

internal/users/users.go

@@ -23,6 +23,7 @@ import (
 	"sync"
 
 	"github.com/ProtonMail/proton-bridge/internal/events"
+	imapcache "github.com/ProtonMail/proton-bridge/internal/imap/cache"
 	"github.com/ProtonMail/proton-bridge/internal/metrics"
 	"github.com/ProtonMail/proton-bridge/pkg/listener"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
@@ -404,6 +405,10 @@ func (u *Users) ClearData() error {
 		result = multierror.Append(result, err)
 	}
 
+	// Need to clear imap cache otherwise fetch response will be remembered
+	// from previous test
+	imapcache.Clear()
+
 	return result
 }
 

internal/versioner/version_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/Masterminds/semver/v3"
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
 	"github.com/ProtonMail/proton-bridge/pkg/sum"
+	tests "github.com/ProtonMail/proton-bridge/test"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -68,7 +69,7 @@ func TestVerifyWithBadFile(t *testing.T) {
 		filepath.Join("sub", "f5.tgz"),
 	)
 
-	badKeyRing := makeKeyRing(t)
+	badKeyRing := tests.MakeKeyRing(t)
 	signFile(t, filepath.Join(tempDir, "f3.bad"), badKeyRing)
 
 	assert.Error(t, version.VerifyFiles(kr))
@@ -91,14 +92,14 @@ func TestVerifyWithBadSubFile(t *testing.T) {
 		filepath.Join("sub", "f5.bad"),
 	)
 
-	badKeyRing := makeKeyRing(t)
+	badKeyRing := tests.MakeKeyRing(t)
 	signFile(t, filepath.Join(tempDir, "sub", "f5.bad"), badKeyRing)
 
 	assert.Error(t, version.VerifyFiles(kr))
 }
 
 func createSignedFiles(t *testing.T, root string, paths ...string) *crypto.KeyRing {
-	kr := makeKeyRing(t)
+	kr := tests.MakeKeyRing(t)
 
 	for _, path := range paths {
 		makeFile(t, filepath.Join(root, path))
@@ -118,16 +119,6 @@ func createSignedFiles(t *testing.T, root string, paths ...string) *crypto.KeyRi
 	return kr
 }
 
-func makeKeyRing(t *testing.T) *crypto.KeyRing {
-	key, err := crypto.GenerateKey("name", "email", "rsa", 2048)
-	require.NoError(t, err)
-
-	kr, err := crypto.NewKeyRing(key)
-	require.NoError(t, err)
-
-	return kr
-}
-
 func makeFile(t *testing.T, path string) {
 	require.NoError(t, os.MkdirAll(filepath.Dir(path), 0700))
 

pkg/algo/sets.go

@@ -19,7 +19,7 @@ package algo
 
 import "reflect"
 
-// SetIntersection complexity: O(n^2), could be better but this is simple enough
+// SetIntersection complexity: O(n^2), could be better but this is simple enough.
 func SetIntersection(a, b interface{}, eq func(a, b interface{}) bool) []interface{} {
 	set := make([]interface{}, 0)
 	av := reflect.ValueOf(a)

pkg/keychain/helper_darwin.go

@@ -86,11 +86,8 @@ func (h *macOSHelper) Delete(secretURL string) error {
 	}
 
 	query := newQuery(hostURL, userID)
-	if err := keychain.DeleteItem(query); err != nil {
-		return err
-	}
 
-	return nil
+	return keychain.DeleteItem(query)
 }
 
 func (h *macOSHelper) Get(secretURL string) (string, string, error) {

pkg/message/body.go

@@ -1,75 +0,0 @@
-// Copyright (c) 2021 Proton Technologies AG
-//
-// This file is part of ProtonMail Bridge.
-//
-// ProtonMail Bridge is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// ProtonMail Bridge is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
-
-package message
-
-import (
-	"encoding/base64"
-	"fmt"
-	"io"
-	"mime/quotedprintable"
-
-	"github.com/ProtonMail/gopenpgp/v2/crypto"
-	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
-	"github.com/emersion/go-textwrapper"
-	openpgperrors "golang.org/x/crypto/openpgp/errors"
-)
-
-func WriteBody(w io.Writer, kr *crypto.KeyRing, m *pmapi.Message) error {
-	// Decrypt body.
-	if err := m.Decrypt(kr); err != nil && err != openpgperrors.ErrSignatureExpired {
-		return err
-	}
-	if m.MIMEType != pmapi.ContentTypeMultipartMixed {
-		// Encode it.
-		qp := quotedprintable.NewWriter(w)
-		if _, err := io.WriteString(qp, m.Body); err != nil {
-			return err
-		}
-		return qp.Close()
-	}
-	_, err := io.WriteString(w, m.Body)
-	return err
-}
-
-func WriteAttachmentBody(w io.Writer, kr *crypto.KeyRing, m *pmapi.Message, att *pmapi.Attachment, r io.Reader) (err error) {
-	// Decrypt it
-	var dr io.Reader
-	dr, err = att.Decrypt(r, kr)
-	if err == openpgperrors.ErrKeyIncorrect {
-		// Do not fail if attachment is encrypted with a different key.
-		dr = r
-		err = nil
-		att.Name += ".gpg"
-		att.MIMEType = "application/pgp-encrypted" //nolint
-	} else if err != nil && err != openpgperrors.ErrSignatureExpired {
-		err = fmt.Errorf("cannot decrypt attachment: %v", err)
-		return
-	}
-
-	// Encode it.
-	ww := textwrapper.NewRFC822(w)
-	bw := base64.NewEncoder(base64.StdEncoding, ww)
-
-	var n int64
-	if n, err = io.Copy(bw, dr); err != nil {
-		err = fmt.Errorf("cannot write attachment: %v (wrote %v bytes)", err, n)
-	}
-
-	_ = bw.Close()
-	return
-}

pkg/message/build.go

@@ -18,331 +18,141 @@
 package message
 
 import (
-	"bytes"
-	"encoding/base64"
-	"fmt"
+	"context"
 	"io"
-	"io/ioutil"
-	"mime/multipart"
-	"mime/quotedprintable"
-	"net/textproto"
+	"sync"
 
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
-	"github.com/emersion/go-textwrapper"
-	openpgperrors "golang.org/x/crypto/openpgp/errors"
+	"github.com/pkg/errors"
+)
+
+var (
+	ErrDecryptionFailed = errors.New("message could not be decrypted")
+	ErrNoSuchKeyRing    = errors.New("the keyring to decrypt this message could not be found")
 )
 
-// Builder for converting PM message to RFC822. Builder will directly write
-// changes to message when fetching or building message.
 type Builder struct {
-	cl  pmapi.Client
-	msg *pmapi.Message
-
-	EncryptedToHTML       bool
-	successfullyDecrypted bool
+	reqs   chan fetchReq
+	done   chan struct{}
+	jobs   map[string]*BuildJob
+	locker sync.Mutex
 }
 
-// NewBuilder initiated with client and message meta info.
-func NewBuilder(client pmapi.Client, message *pmapi.Message) *Builder {
-	return &Builder{cl: client, msg: message, EncryptedToHTML: true, successfullyDecrypted: false}
+type Fetcher interface {
+	GetMessage(string) (*pmapi.Message, error)
+	GetAttachment(string) (io.ReadCloser, error)
+	KeyRingForAddressID(string) (*crypto.KeyRing, error)
 }
 
-// fetchMessage will update original PM message if successful
-func (bld *Builder) fetchMessage() (err error) {
-	if bld.msg.Body != "" {
-		return nil
-	}
+// NewBuilder creates a new builder which manages the given number of fetch/attach/build workers.
+//  - fetchWorkers: the number of workers which fetch messages from API
+//  - attachWorkers: the number of workers which fetch attachments from API.
+//  - buildWorkers: the number of workers which decrypt/build RFC822 message literals.
+//
+// NOTE: Each fetch worker spawns a unique set of attachment workers!
+// There can therefore be up to fetchWorkers*attachWorkers simultaneous API connections.
+//
+// The returned builder is ready to handle jobs -- see (*Builder).NewJob for more information.
+//
+// Call (*Builder).Done to shut down the builder and stop all workers.
+func NewBuilder(fetchWorkers, attachWorkers, buildWorkers int) *Builder {
+	b := newBuilder()
 
-	complete, err := bld.cl.GetMessage(bld.msg.ID)
-	if err != nil {
-		return
-	}
+	fetchReqCh, fetchResCh := startFetchWorkers(fetchWorkers, attachWorkers)
+	buildReqCh, buildResCh := startBuildWorkers(buildWorkers)
 
-	*bld.msg = *complete
+	go func() {
+		defer close(fetchReqCh)
 
-	return
-}
+		for {
+			select {
+			case req := <-b.reqs:
+				fetchReqCh <- req
 
-func (bld *Builder) writeMessageBody(w io.Writer) error {
-	if err := bld.fetchMessage(); err != nil {
-		return err
-	}
-
-	err := bld.WriteBody(w)
-	if err != nil {
-		_, _ = io.WriteString(w, "\r\n")
-		if bld.EncryptedToHTML {
-			_ = CustomMessage(bld.msg, err, true)
-		}
-		_, err = io.WriteString(w, bld.msg.Body)
-		_, _ = io.WriteString(w, "\r\n")
-	}
-
-	return err
-}
-
-func (bld *Builder) writeAttachmentBody(w io.Writer, att *pmapi.Attachment) error {
-	// Retrieve encrypted attachment
-	r, err := bld.cl.GetAttachment(att.ID)
-	if err != nil {
-		return err
-	}
-	defer r.Close() //nolint[errcheck]
-
-	if err := bld.WriteAttachmentBody(w, att, r); err != nil {
-		// Returning an error here makes e-mail clients like Thunderbird behave
-		// badly, trying to retrieve the message again and again
-		log.Warnln("Cannot write attachment body:", err)
-	}
-	return nil
-}
-
-func (bld *Builder) writeRelatedPart(p io.Writer, inlines []*pmapi.Attachment) error {
-	related := multipart.NewWriter(p)
-
-	_ = related.SetBoundary(GetRelatedBoundary(bld.msg))
-
-	buf := &bytes.Buffer{}
-	if err := bld.writeMessageBody(buf); err != nil {
-		return err
-	}
-
-	// Write the body part
-	h := GetBodyHeader(bld.msg)
-
-	var err error
-	if p, err = related.CreatePart(h); err != nil {
-		return err
-	}
-
-	_, _ = buf.WriteTo(p)
-
-	for _, inline := range inlines {
-		buf = &bytes.Buffer{}
-		if err = bld.writeAttachmentBody(buf, inline); err != nil {
-			return err
-		}
-
-		h := GetAttachmentHeader(inline)
-		if p, err = related.CreatePart(h); err != nil {
-			return err
-		}
-		_, _ = buf.WriteTo(p)
-	}
-
-	_ = related.Close()
-	return nil
-}
-
-// BuildMessage converts PM message to body structure (not RFC3501) and bytes
-// of RC822 message. If successful the original PM message will contain decrypted body.
-func (bld *Builder) BuildMessage() (structure *BodyStructure, message []byte, err error) { //nolint[funlen]
-	if err = bld.fetchMessage(); err != nil {
-		return nil, nil, err
-	}
-
-	bodyBuf := &bytes.Buffer{}
-
-	mainHeader := GetHeader(bld.msg)
-	mainHeader.Set("Content-Type", "multipart/mixed; boundary="+GetBoundary(bld.msg))
-	if err = WriteHeader(bodyBuf, mainHeader); err != nil {
-		return nil, nil, err
-	}
-	_, _ = io.WriteString(bodyBuf, "\r\n")
-
-	// NOTE: Do we really need extra encapsulation? i.e. Bridge-IMAP message is always multipart/mixed
-
-	if bld.msg.MIMEType == pmapi.ContentTypeMultipartMixed {
-		_, _ = io.WriteString(bodyBuf, "\r\n--"+GetBoundary(bld.msg)+"\r\n")
-		if err = bld.writeMessageBody(bodyBuf); err != nil {
-			return nil, nil, err
-		}
-		_, _ = io.WriteString(bodyBuf, "\r\n--"+GetBoundary(bld.msg)+"--\r\n")
-	} else {
-		mw := multipart.NewWriter(bodyBuf)
-		_ = mw.SetBoundary(GetBoundary(bld.msg))
-
-		var partWriter io.Writer
-		atts, inlines := SeparateInlineAttachments(bld.msg)
-
-		if len(inlines) > 0 {
-			relatedHeader := GetRelatedHeader(bld.msg)
-			if partWriter, err = mw.CreatePart(relatedHeader); err != nil {
-				return nil, nil, err
+			case <-b.done:
+				return
 			}
-			_ = bld.writeRelatedPart(partWriter, inlines)
-		} else {
-			buf := &bytes.Buffer{}
-			if err = bld.writeMessageBody(buf); err != nil {
-				return nil, nil, err
-			}
-
-			// Write the body part
-			bodyHeader := GetBodyHeader(bld.msg)
-			if partWriter, err = mw.CreatePart(bodyHeader); err != nil {
-				return nil, nil, err
-			}
-
-			_, _ = buf.WriteTo(partWriter)
 		}
+	}()
 
-		// Write the attachments parts
-		for _, att := range atts {
-			buf := &bytes.Buffer{}
-			if err = bld.writeAttachmentBody(buf, att); err != nil {
-				return nil, nil, err
+	go func() {
+		defer close(buildReqCh)
+
+		for res := range fetchResCh {
+			if res.err != nil {
+				b.jobFailure(res.messageID, res.err)
+			} else {
+				buildReqCh <- res
 			}
-
-			attachmentHeader := GetAttachmentHeader(att)
-			if partWriter, err = mw.CreatePart(attachmentHeader); err != nil {
-				return nil, nil, err
-			}
-
-			_, _ = buf.WriteTo(partWriter)
 		}
+	}()
 
-		_ = mw.Close()
-	}
+	go func() {
+		for res := range buildResCh {
+			if res.err != nil {
+				b.jobFailure(res.messageID, res.err)
+			} else {
+				b.jobSuccess(res.messageID, res.literal)
+			}
+		}
+	}()
 
-	// wee need to copy buffer before building body structure
-	message = bodyBuf.Bytes()
-	structure, err = NewBodyStructure(bodyBuf)
-	return structure, message, err
+	return b
 }
 
-// SuccessfullyDecrypted is true when message was fetched and decrypted successfully
-func (bld *Builder) SuccessfullyDecrypted() bool { return bld.successfullyDecrypted }
-
-// WriteBody decrypts PM message and writes main body section. The external PGP
-// message is written as is (including attachments)
-func (bld *Builder) WriteBody(w io.Writer) error {
-	kr, err := bld.cl.KeyRingForAddressID(bld.msg.AddressID)
-	if err != nil {
-		return err
+func newBuilder() *Builder {
+	return &Builder{
+		reqs: make(chan fetchReq),
+		done: make(chan struct{}),
+		jobs: make(map[string]*BuildJob),
 	}
-	// decrypt body
-	if err := bld.msg.Decrypt(kr); err != nil && err != openpgperrors.ErrSignatureExpired {
-		return err
-	}
-	bld.successfullyDecrypted = true
-	if bld.msg.MIMEType != pmapi.ContentTypeMultipartMixed {
-		// transfer encoding
-		qp := quotedprintable.NewWriter(w)
-		if _, err := io.WriteString(qp, bld.msg.Body); err != nil {
-			return err
-		}
-		return qp.Close()
-	}
-	_, err = io.WriteString(w, bld.msg.Body)
-	return err
 }
 
-// WriteAttachmentBody decrypts and writes the attachments
-func (bld *Builder) WriteAttachmentBody(w io.Writer, att *pmapi.Attachment, attReader io.Reader) (err error) {
-	kr, err := bld.cl.KeyRingForAddressID(bld.msg.AddressID)
-	if err != nil {
-		return err
-	}
-	// Decrypt it
-	var dr io.Reader
-	dr, err = att.Decrypt(attReader, kr)
-	if err == openpgperrors.ErrKeyIncorrect {
-		// Do not fail if attachment is encrypted with a different key
-		dr = attReader
-		err = nil
-		att.Name += ".gpg"
-		att.MIMEType = "application/pgp-encrypted"
-	} else if err != nil && err != openpgperrors.ErrSignatureExpired {
-		err = fmt.Errorf("cannot decrypt attachment: %v", err)
-		return err
-	}
-
-	// transfer encoding
-	ww := textwrapper.NewRFC822(w)
-	bw := base64.NewEncoder(base64.StdEncoding, ww)
-
-	var n int64
-	if n, err = io.Copy(bw, dr); err != nil {
-		err = fmt.Errorf("cannot write attachment: %v (wrote %v bytes)", err, n)
-	}
-
-	_ = bw.Close()
-	return err
+// NewJob tells the builder to begin building the message with the given ID.
+// The result (or any error which occurred during building) can be retrieved from the returned job when available.
+func (b *Builder) NewJob(ctx context.Context, api Fetcher, messageID string) *BuildJob {
+	return b.NewJobWithOptions(ctx, api, messageID, JobOptions{})
 }
 
-func BuildEncrypted(m *pmapi.Message, readers []io.Reader, kr *crypto.KeyRing) ([]byte, error) { //nolint[funlen]
-	b := &bytes.Buffer{}
+// NewJobWithOptions creates a new job with custom options. See NewJob for more information.
+func (b *Builder) NewJobWithOptions(ctx context.Context, api Fetcher, messageID string, opts JobOptions) *BuildJob {
+	b.locker.Lock()
+	defer b.locker.Unlock()
 
-	// Overwrite content for main header for import.
-	// Even if message has just simple body we should upload as multipart/mixed.
-	// Each part has encrypted body and header reflects the original header.
-	mainHeader := GetHeader(m)
-	mainHeader.Set("Content-Type", "multipart/mixed; boundary="+GetBoundary(m))
-	mainHeader.Del("Content-Disposition")
-	mainHeader.Del("Content-Transfer-Encoding")
-	if err := WriteHeader(b, mainHeader); err != nil {
-		return nil, err
-	}
-	mw := multipart.NewWriter(b)
-	if err := mw.SetBoundary(GetBoundary(m)); err != nil {
-		return nil, err
+	if job, ok := b.jobs[messageID]; ok {
+		return job
 	}
 
-	// Write the body part.
-	bodyHeader := make(textproto.MIMEHeader)
-	bodyHeader.Set("Content-Type", m.MIMEType+"; charset=utf-8")
-	bodyHeader.Set("Content-Disposition", "inline")
-	bodyHeader.Set("Content-Transfer-Encoding", "7bit")
+	b.jobs[messageID] = newBuildJob(messageID)
 
-	p, err := mw.CreatePart(bodyHeader)
-	if err != nil {
-		return nil, err
-	}
-	// First, encrypt the message body.
-	if err := m.Encrypt(kr, kr); err != nil {
-		return nil, err
-	}
-	if _, err := io.WriteString(p, m.Body); err != nil {
-		return nil, err
-	}
+	go func() { b.reqs <- fetchReq{ctx: ctx, api: api, messageID: messageID, opts: opts} }()
 
-	// Write the attachments parts.
-	for i := 0; i < len(m.Attachments); i++ {
-		att := m.Attachments[i]
-		r := readers[i]
-		h := GetAttachmentHeader(att)
-		p, err := mw.CreatePart(h)
-		if err != nil {
-			return nil, err
-		}
-		// Create line wrapper writer.
-		ww := textwrapper.NewRFC822(p)
-
-		// Create base64 writer.
-		bw := base64.NewEncoder(base64.StdEncoding, ww)
-
-		data, err := ioutil.ReadAll(r)
-		if err != nil {
-			return nil, err
-		}
-
-		// Create encrypted writer.
-		pgpMessage, err := kr.Encrypt(crypto.NewPlainMessage(data), nil)
-		if err != nil {
-			return nil, err
-		}
-		if _, err := bw.Write(pgpMessage.GetBinary()); err != nil {
-			return nil, err
-		}
-		if err := bw.Close(); err != nil {
-			return nil, err
-		}
-	}
-
-	if err := mw.Close(); err != nil {
-		return nil, err
-	}
-
-	return b.Bytes(), nil
+	return b.jobs[messageID]
+}
+
+// Done shuts down the builder and stops all workers.
+func (b *Builder) Done() {
+	b.locker.Lock()
+	defer b.locker.Unlock()
+
+	close(b.done)
+}
+
+func (b *Builder) jobSuccess(messageID string, literal []byte) {
+	b.locker.Lock()
+	defer b.locker.Unlock()
+
+	b.jobs[messageID].postSuccess(literal)
+
+	delete(b.jobs, messageID)
+}
+
+func (b *Builder) jobFailure(messageID string, err error) {
+	b.locker.Lock()
+	defer b.locker.Unlock()
+
+	b.jobs[messageID].postFailure(err)
+
+	delete(b.jobs, messageID)
 }

pkg/message/build_boundary.go

@@ -18,39 +18,26 @@
 package message
 
 import (
-	"net/mail"
-	"strings"
-
-	"github.com/emersion/go-imap"
+	"crypto/sha256"
+	"encoding/hex"
 )
 
-func getAddresses(addrs []*mail.Address) (imapAddrs []*imap.Address) {
-	for _, a := range addrs {
-		if a == nil {
-			continue
-		}
-
-		parts := strings.SplitN(a.Address, "@", 2)
-		if len(parts) != 2 {
-			continue
-		}
-
-		imapAddrs = append(imapAddrs, &imap.Address{
-			PersonalName: a.Name,
-			MailboxName:  parts[0],
-			HostName:     parts[1],
-		})
-	}
-
-	return
+type boundary struct {
+	val string
 }
 
-func formatAddressList(addrs []*mail.Address) (s string) {
-	for i, addr := range addrs {
-		if i > 0 {
-			s += ", "
-		}
-		s += addr.String()
-	}
-	return
+func newBoundary(seed string) *boundary {
+	return &boundary{val: seed}
+}
+
+func (bw *boundary) gen() string {
+	hash := sha256.New()
+
+	if _, err := hash.Write([]byte(bw.val)); err != nil {
+		panic(err)
+	}
+
+	bw.val = hex.EncodeToString(hash.Sum(nil))
+
+	return bw.val
 }

pkg/message/build_build.go

@@ -0,0 +1,89 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+import (
+	"sync"
+
+	"github.com/pkg/errors"
+)
+
+type buildRes struct {
+	messageID string
+	literal   []byte
+	err       error
+}
+
+func newBuildResSuccess(messageID string, literal []byte) buildRes {
+	return buildRes{
+		messageID: messageID,
+		literal:   literal,
+	}
+}
+
+func newBuildResFailure(messageID string, err error) buildRes {
+	return buildRes{
+		messageID: messageID,
+		err:       err,
+	}
+}
+
+// startBuildWorkers starts the given number of build workers.
+// These workers decrypt and build messages into RFC822 literals.
+// Two channels are returned:
+//  - buildReqCh: used to send work items to the worker pool
+//  - buildResCh: used to receive work results from the worker pool
+func startBuildWorkers(buildWorkers int) (chan fetchRes, chan buildRes) {
+	buildReqCh := make(chan fetchRes)
+	buildResCh := make(chan buildRes)
+
+	go func() {
+		defer close(buildResCh)
+
+		var wg sync.WaitGroup
+
+		wg.Add(buildWorkers)
+
+		for workerID := 0; workerID < buildWorkers; workerID++ {
+			go buildWorker(buildReqCh, buildResCh, &wg)
+		}
+
+		wg.Wait()
+	}()
+
+	return buildReqCh, buildResCh
+}
+
+func buildWorker(buildReqCh <-chan fetchRes, buildResCh chan<- buildRes, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	for req := range buildReqCh {
+		l := log.
+			WithField("addrID", req.msg.AddressID).
+			WithField("msgID", req.msg.ID)
+		if kr, err := req.api.KeyRingForAddressID(req.msg.AddressID); err != nil {
+			l.WithError(err).Warn("Cannot find keyring for address")
+			buildResCh <- newBuildResFailure(req.msg.ID, errors.Wrap(ErrNoSuchKeyRing, err.Error()))
+		} else if literal, err := buildRFC822(kr, req.msg, req.atts, req.opts); err != nil {
+			l.WithError(err).Warn("Build failed")
+			buildResCh <- newBuildResFailure(req.msg.ID, err)
+		} else {
+			buildResCh <- newBuildResSuccess(req.msg.ID, literal)
+		}
+	}
+}

pkg/message/build_encrypted.go

@@ -0,0 +1,114 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+import (
+	"bytes"
+	"encoding/base64"
+	"io"
+	"io/ioutil"
+	"mime/multipart"
+	"net/http"
+	"net/textproto"
+
+	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
+	"github.com/emersion/go-textwrapper"
+)
+
+func BuildEncrypted(m *pmapi.Message, readers []io.Reader, kr *crypto.KeyRing) ([]byte, error) { //nolint[funlen]
+	b := &bytes.Buffer{}
+
+	// Overwrite content for main header for import.
+	// Even if message has just simple body we should upload as multipart/mixed.
+	// Each part has encrypted body and header reflects the original header.
+	mainHeader := GetHeader(m)
+	mainHeader.Set("Content-Type", "multipart/mixed; boundary="+GetBoundary(m))
+	mainHeader.Del("Content-Disposition")
+	mainHeader.Del("Content-Transfer-Encoding")
+	if err := WriteHeader(b, mainHeader); err != nil {
+		return nil, err
+	}
+	mw := multipart.NewWriter(b)
+	if err := mw.SetBoundary(GetBoundary(m)); err != nil {
+		return nil, err
+	}
+
+	// Write the body part.
+	bodyHeader := make(textproto.MIMEHeader)
+	bodyHeader.Set("Content-Type", m.MIMEType+"; charset=utf-8")
+	bodyHeader.Set("Content-Disposition", pmapi.DispositionInline)
+	bodyHeader.Set("Content-Transfer-Encoding", "7bit")
+
+	p, err := mw.CreatePart(bodyHeader)
+	if err != nil {
+		return nil, err
+	}
+	// First, encrypt the message body.
+	if err := m.Encrypt(kr, kr); err != nil {
+		return nil, err
+	}
+	if _, err := io.WriteString(p, m.Body); err != nil {
+		return nil, err
+	}
+
+	// Write the attachments parts.
+	for i := 0; i < len(m.Attachments); i++ {
+		att := m.Attachments[i]
+		r := readers[i]
+		h := GetAttachmentHeader(att, false)
+		p, err := mw.CreatePart(h)
+		if err != nil {
+			return nil, err
+		}
+
+		data, err := ioutil.ReadAll(r)
+		if err != nil {
+			return nil, err
+		}
+
+		// Create encrypted writer.
+		pgpMessage, err := kr.Encrypt(crypto.NewPlainMessage(data), nil)
+		if err != nil {
+			return nil, err
+		}
+
+		ww := textwrapper.NewRFC822(p)
+		bw := base64.NewEncoder(base64.StdEncoding, ww)
+		if _, err := bw.Write(pgpMessage.GetBinary()); err != nil {
+			return nil, err
+		}
+		if err := bw.Close(); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := mw.Close(); err != nil {
+		return nil, err
+	}
+
+	return b.Bytes(), nil
+}
+
+func WriteHeader(w io.Writer, h textproto.MIMEHeader) (err error) {
+	if err = http.Header(h).Write(w); err != nil {
+		return
+	}
+	_, err = io.WriteString(w, "\r\n")
+	return
+}

pkg/message/build_fetch.go

@@ -0,0 +1,141 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+import (
+	"context"
+	"io/ioutil"
+	"sync"
+
+	"github.com/ProtonMail/proton-bridge/pkg/parallel"
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
+)
+
+type fetchReq struct {
+	ctx       context.Context
+	api       Fetcher
+	messageID string
+	opts      JobOptions
+}
+
+type fetchRes struct {
+	fetchReq
+
+	msg  *pmapi.Message
+	atts [][]byte
+	err  error
+}
+
+func newFetchResSuccess(req fetchReq, msg *pmapi.Message, atts [][]byte) fetchRes {
+	return fetchRes{
+		fetchReq: req,
+		msg:      msg,
+		atts:     atts,
+	}
+}
+
+func newFetchResFailure(req fetchReq, err error) fetchRes {
+	return fetchRes{
+		fetchReq: req,
+		err:      err,
+	}
+}
+
+// startFetchWorkers starts the given number of fetch workers.
+// These workers download message and attachment data from API.
+// Each fetch worker will use up to the given number of attachment workers to download attachments.
+// Two channels are returned:
+//  - fetchReqCh: used to send work items to the worker pool
+//  - fetchResCh: used to receive work results from the worker pool
+func startFetchWorkers(fetchWorkers, attachWorkers int) (chan fetchReq, chan fetchRes) {
+	fetchReqCh := make(chan fetchReq)
+	fetchResCh := make(chan fetchRes)
+
+	go func() {
+		defer close(fetchResCh)
+
+		var wg sync.WaitGroup
+
+		wg.Add(fetchWorkers)
+
+		for workerID := 0; workerID < fetchWorkers; workerID++ {
+			go fetchWorker(fetchReqCh, fetchResCh, attachWorkers, &wg)
+		}
+
+		wg.Wait()
+	}()
+
+	return fetchReqCh, fetchResCh
+}
+
+func fetchWorker(fetchReqCh <-chan fetchReq, fetchResCh chan<- fetchRes, attachWorkers int, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	for req := range fetchReqCh {
+		msg, atts, err := fetchMessage(req, attachWorkers)
+		if err != nil {
+			fetchResCh <- newFetchResFailure(req, err)
+		} else {
+			fetchResCh <- newFetchResSuccess(req, msg, atts)
+		}
+	}
+}
+
+func fetchMessage(req fetchReq, attachWorkers int) (*pmapi.Message, [][]byte, error) {
+	msg, err := req.api.GetMessage(req.messageID)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	attList := make([]interface{}, len(msg.Attachments))
+
+	for i, att := range msg.Attachments {
+		attList[i] = att.ID
+	}
+
+	process := func(value interface{}) (interface{}, error) {
+		rc, err := req.api.GetAttachment(value.(string))
+		if err != nil {
+			return nil, err
+		}
+
+		b, err := ioutil.ReadAll(rc)
+		if err != nil {
+			return nil, err
+		}
+
+		if err := rc.Close(); err != nil {
+			return nil, err
+		}
+
+		return b, nil
+	}
+
+	attData := make([][]byte, len(msg.Attachments))
+
+	collect := func(idx int, value interface{}) error {
+		attData[idx] = value.([]byte) //nolint[forcetypeassert] we wan't to panic here
+		return nil
+	}
+
+	if err := parallel.RunParallel(attachWorkers, attList, process, collect); err != nil {
+		return nil, nil, err
+	}
+
+	return msg, attData, nil
+}

pkg/message/build_framework_test.go

@@ -0,0 +1,332 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/base64"
+	"io"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/ProtonMail/proton-bridge/pkg/message/mocks"
+	"github.com/ProtonMail/proton-bridge/pkg/message/parser"
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func newTestFetcher(
+	m *gomock.Controller,
+	kr *crypto.KeyRing,
+	msg *pmapi.Message,
+	attData ...[]byte,
+) Fetcher {
+	f := mocks.NewMockFetcher(m)
+
+	f.EXPECT().GetMessage(msg.ID).Return(msg, nil)
+
+	for i, att := range msg.Attachments {
+		f.EXPECT().GetAttachment(att.ID).Return(newTestReadCloser(attData[i]), nil)
+	}
+
+	f.EXPECT().KeyRingForAddressID(msg.AddressID).Return(kr, nil)
+
+	return f
+}
+
+func newTestMessage(
+	t *testing.T,
+	kr *crypto.KeyRing,
+	messageID, addressID, mimeType, body string, // nolint[unparam]
+	date time.Time,
+) *pmapi.Message {
+	enc, err := kr.Encrypt(crypto.NewPlainMessageFromString(body), kr)
+	require.NoError(t, err)
+
+	arm, err := enc.GetArmored()
+	require.NoError(t, err)
+
+	return &pmapi.Message{
+		ID:        messageID,
+		AddressID: addressID,
+		MIMEType:  mimeType,
+		Header: map[string][]string{
+			"Content-Type": {mimeType},
+			"Date":         {date.In(time.UTC).Format(time.RFC1123Z)},
+		},
+		Body: arm,
+		Time: date.Unix(),
+	}
+}
+
+func addTestAttachment(
+	t *testing.T,
+	kr *crypto.KeyRing,
+	msg *pmapi.Message,
+	attachmentID, name, mimeType, disposition, data string,
+) []byte {
+	enc, err := kr.EncryptAttachment(crypto.NewPlainMessageFromString(data), attachmentID+".bin")
+	require.NoError(t, err)
+
+	msg.Attachments = append(msg.Attachments, &pmapi.Attachment{
+		ID:       attachmentID,
+		Name:     name,
+		MIMEType: mimeType,
+		Header: map[string][]string{
+			"Content-Type":              {mimeType},
+			"Content-Disposition":       {disposition},
+			"Content-Transfer-Encoding": {"base64"},
+		},
+		Disposition: disposition,
+		KeyPackets:  base64.StdEncoding.EncodeToString(enc.GetBinaryKeyPacket()),
+	})
+
+	return enc.GetBinaryDataPacket()
+}
+
+type testReadCloser struct {
+	io.Reader
+}
+
+func newTestReadCloser(b []byte) *testReadCloser {
+	return &testReadCloser{Reader: bytes.NewReader(b)}
+}
+
+func (testReadCloser) Close() error {
+	return nil
+}
+
+type testSection struct {
+	t    *testing.T
+	part *parser.Part
+	raw  []byte
+}
+
+// NOTE: Each section is parsed individually --> cleaner test code but slower... improve this one day?
+func section(t *testing.T, b []byte, section ...int) *testSection {
+	p, err := parser.New(bytes.NewReader(b))
+	assert.NoError(t, err)
+
+	part, err := p.Section(section)
+	require.NoError(t, err)
+
+	bs, err := NewBodyStructure(bytes.NewReader(b))
+	require.NoError(t, err)
+
+	raw, err := bs.GetSection(bytes.NewReader(b), append([]int{}, section...))
+	require.NoError(t, err)
+
+	return &testSection{
+		t:    t,
+		part: part,
+		raw:  raw,
+	}
+}
+
+func (s *testSection) expectBody(wantBody matcher) *testSection {
+	wantBody.match(s.t, string(s.part.Body))
+
+	return s
+}
+
+func (s *testSection) expectSection(wantSection matcher) *testSection { // nolint[unparam]
+	wantSection.match(s.t, string(s.raw))
+
+	return s
+}
+
+func (s *testSection) expectContentType(wantContentType matcher) *testSection {
+	mimeType, _, err := s.part.Header.ContentType()
+	require.NoError(s.t, err)
+
+	wantContentType.match(s.t, mimeType)
+
+	return s
+}
+
+func (s *testSection) expectContentTypeParam(key string, wantParam matcher) *testSection { // nolint[unparam]
+	_, params, err := s.part.Header.ContentType()
+	require.NoError(s.t, err)
+
+	wantParam.match(s.t, params[key])
+
+	return s
+}
+
+func (s *testSection) expectContentDisposition(wantDisposition matcher) *testSection {
+	disposition, _, err := s.part.Header.ContentDisposition()
+	require.NoError(s.t, err)
+
+	wantDisposition.match(s.t, disposition)
+
+	return s
+}
+
+func (s *testSection) expectContentDispositionParam(key string, wantParam matcher) *testSection { // nolint[unparam]
+	_, params, err := s.part.Header.ContentDisposition()
+	require.NoError(s.t, err)
+
+	wantParam.match(s.t, params[key])
+
+	return s
+}
+
+func (s *testSection) expectTransferEncoding(wantTransferEncoding matcher) *testSection {
+	wantTransferEncoding.match(s.t, s.part.Header.Get("Content-Transfer-Encoding"))
+
+	return s
+}
+
+func (s *testSection) expectDate(wantDate matcher) *testSection {
+	wantDate.match(s.t, s.part.Header.Get("Date"))
+
+	return s
+}
+
+func (s *testSection) expectHeader(key string, wantValue matcher) *testSection {
+	wantValue.match(s.t, s.part.Header.Get(key))
+
+	return s
+}
+
+func (s *testSection) expectDecodedHeader(key string, wantValue matcher) *testSection { // nolint[unparam]
+	dec, err := s.part.Header.Text(key)
+	require.NoError(s.t, err)
+
+	wantValue.match(s.t, dec)
+
+	return s
+}
+
+func (s *testSection) pubKey() *crypto.KeyRing {
+	key, err := crypto.NewKeyFromArmored(string(s.part.Body))
+	require.NoError(s.t, err)
+
+	kr, err := crypto.NewKeyRing(key)
+	require.NoError(s.t, err)
+
+	return kr
+}
+
+func (s *testSection) signature() *crypto.PGPSignature {
+	sig, err := crypto.NewPGPSignatureFromArmored(string(s.part.Body))
+	require.NoError(s.t, err)
+
+	return sig
+}
+
+type matcher interface {
+	match(*testing.T, string)
+}
+
+type isMatcher struct {
+	want string
+}
+
+func (matcher isMatcher) match(t *testing.T, have string) {
+	assert.Equal(t, matcher.want, have)
+}
+
+func is(want string) isMatcher {
+	return isMatcher{want: want}
+}
+
+func isMissing() isMatcher {
+	return isMatcher{}
+}
+
+type isNotMatcher struct {
+	notWant string
+}
+
+func (matcher isNotMatcher) match(t *testing.T, have string) {
+	assert.NotEqual(t, matcher.notWant, have)
+}
+
+func isNot(notWant string) isNotMatcher {
+	return isNotMatcher{notWant: notWant}
+}
+
+type containsMatcher struct {
+	contains string
+}
+
+func (matcher containsMatcher) match(t *testing.T, have string) {
+	assert.Contains(t, have, matcher.contains)
+}
+
+func contains(contains string) containsMatcher {
+	return containsMatcher{contains: contains}
+}
+
+type decryptsToMatcher struct {
+	kr   *crypto.KeyRing
+	want string
+}
+
+func (matcher decryptsToMatcher) match(t *testing.T, have string) {
+	haveMsg, err := crypto.NewPGPMessageFromArmored(have)
+	require.NoError(t, err)
+
+	dec, err := matcher.kr.Decrypt(haveMsg, nil, crypto.GetUnixTime())
+	require.NoError(t, err)
+
+	assert.Equal(t, matcher.want, dec.GetString())
+}
+
+func decryptsTo(kr *crypto.KeyRing, want string) decryptsToMatcher {
+	return decryptsToMatcher{kr: kr, want: want}
+}
+
+type verifiesAgainstMatcher struct {
+	kr  *crypto.KeyRing
+	sig *crypto.PGPSignature
+}
+
+func (matcher verifiesAgainstMatcher) match(t *testing.T, have string) {
+	assert.NoError(t, matcher.kr.VerifyDetached(
+		crypto.NewPlainMessage(bytes.TrimSuffix([]byte(have), []byte("\r\n"))),
+		matcher.sig,
+		crypto.GetUnixTime()),
+	)
+}
+
+func verifiesAgainst(kr *crypto.KeyRing, sig *crypto.PGPSignature) verifiesAgainstMatcher {
+	return verifiesAgainstMatcher{kr: kr, sig: sig}
+}
+
+type maxLineLengthMatcher struct {
+	wantMax int
+}
+
+func (matcher maxLineLengthMatcher) match(t *testing.T, have string) {
+	scanner := bufio.NewScanner(strings.NewReader(have))
+
+	for scanner.Scan() {
+		assert.Less(t, len(scanner.Text()), matcher.wantMax)
+	}
+}
+
+func hasMaxLineLength(wantMax int) maxLineLengthMatcher {
+	return maxLineLengthMatcher{wantMax: wantMax}
+}

pkg/message/build_job.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+type JobOptions struct {
+	IgnoreDecryptionErrors bool // Whether to ignore decryption errors and create a "custom message" instead.
+	SanitizeDate           bool // Whether to replace all dates before 1970 with RFC822's birthdate.
+	AddInternalID          bool // Whether to include MessageID as X-Pm-Internal-Id.
+	AddExternalID          bool // Whether to include ExternalID as X-Pm-External-Id.
+	AddMessageDate         bool // Whether to include message time as X-Pm-Date.
+	AddMessageIDReference  bool // Whether to include the MessageID in References.
+}
+
+type BuildJob struct {
+	messageID string
+	literal   []byte
+	err       error
+
+	done chan struct{}
+}
+
+func newBuildJob(messageID string) *BuildJob {
+	return &BuildJob{
+		messageID: messageID,
+		done:      make(chan struct{}),
+	}
+}
+
+// GetResult returns the build result or any error which occurred during building.
+// If the result is not ready yet, it blocks.
+func (job *BuildJob) GetResult() ([]byte, error) {
+	<-job.done
+	return job.literal, job.err
+}
+
+func (job *BuildJob) postSuccess(literal []byte) {
+	job.literal = literal
+	close(job.done)
+}
+
+func (job *BuildJob) postFailure(err error) {
+	job.err = err
+	close(job.done)
+}

pkg/message/build_rfc822.go

@@ -0,0 +1,434 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+import (
+	"bytes"
+	"encoding/base64"
+	"io/ioutil"
+	"mime"
+	"net/mail"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/ProtonMail/go-rfc5322"
+	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
+	"github.com/emersion/go-message"
+	"github.com/pkg/errors"
+)
+
+func buildRFC822(kr *crypto.KeyRing, msg *pmapi.Message, attData [][]byte, opts JobOptions) ([]byte, error) {
+	switch {
+	case len(msg.Attachments) > 0:
+		return buildMultipartRFC822(kr, msg, attData, opts)
+
+	case msg.MIMEType == "multipart/mixed":
+		return buildEncryptedRFC822(kr, msg, opts)
+
+	default:
+		return buildSimpleRFC822(kr, msg, opts)
+	}
+}
+
+func buildSimpleRFC822(kr *crypto.KeyRing, msg *pmapi.Message, opts JobOptions) ([]byte, error) {
+	dec, err := msg.Decrypt(kr)
+	if err != nil {
+		if !opts.IgnoreDecryptionErrors {
+			return nil, errors.Wrap(ErrDecryptionFailed, err.Error())
+		}
+
+		return buildMultipartRFC822(kr, msg, nil, opts)
+	}
+
+	hdr := getTextPartHeader(getMessageHeader(msg, opts), dec, msg.MIMEType)
+
+	buf := new(bytes.Buffer)
+
+	w, err := message.CreateWriter(buf, hdr)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err := w.Write(dec); err != nil {
+		return nil, err
+	}
+
+	if err := w.Close(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func buildMultipartRFC822(
+	kr *crypto.KeyRing,
+	msg *pmapi.Message,
+	attData [][]byte,
+	opts JobOptions,
+) ([]byte, error) {
+	boundary := newBoundary(msg.ID)
+
+	hdr := getMessageHeader(msg, opts)
+
+	hdr.SetContentType("multipart/mixed", map[string]string{"boundary": boundary.gen()})
+
+	buf := new(bytes.Buffer)
+
+	w, err := message.CreateWriter(buf, hdr)
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		inlineAtts []*pmapi.Attachment
+		inlineData [][]byte
+		attachAtts []*pmapi.Attachment
+		attachData [][]byte
+	)
+
+	for i, att := range msg.Attachments {
+		if att.Disposition == pmapi.DispositionInline {
+			inlineAtts = append(inlineAtts, att)
+			inlineData = append(inlineData, attData[i])
+		} else {
+			attachAtts = append(attachAtts, att)
+			attachData = append(attachData, attData[i])
+		}
+	}
+
+	if len(inlineAtts) > 0 {
+		if err := writeRelatedParts(w, kr, boundary, msg, inlineAtts, inlineData, opts); err != nil {
+			return nil, err
+		}
+	} else if err := writeTextPart(w, kr, msg, opts); err != nil {
+		return nil, err
+	}
+
+	for i, att := range attachAtts {
+		if err := writeAttachmentPart(w, kr, att, attachData[i], opts); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := w.Close(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func writeTextPart(
+	w *message.Writer,
+	kr *crypto.KeyRing,
+	msg *pmapi.Message,
+	opts JobOptions,
+) error {
+	dec, err := msg.Decrypt(kr)
+	if err != nil {
+		if !opts.IgnoreDecryptionErrors {
+			return errors.Wrap(ErrDecryptionFailed, err.Error())
+		}
+
+		/*
+			if len(msg.Attachments) > 0 {
+				return writeCustomTextPartAsAttachment(w, msg, err)
+			}
+		*/
+
+		return writeCustomTextPart(w, msg, err)
+	}
+
+	part, err := w.CreatePart(getTextPartHeader(message.Header{}, dec, msg.MIMEType))
+	if err != nil {
+		return err
+	}
+
+	if _, err := part.Write(dec); err != nil {
+		return err
+	}
+
+	return part.Close()
+}
+
+func writeAttachmentPart(
+	w *message.Writer,
+	kr *crypto.KeyRing,
+	att *pmapi.Attachment,
+	attData []byte,
+	opts JobOptions,
+) error {
+	kps, err := base64.StdEncoding.DecodeString(att.KeyPackets)
+	if err != nil {
+		return err
+	}
+
+	msg := crypto.NewPGPSplitMessage(kps, attData).GetPGPMessage()
+
+	dec, err := kr.Decrypt(msg, nil, crypto.GetUnixTime())
+	if err != nil {
+		if !opts.IgnoreDecryptionErrors {
+			return errors.Wrap(ErrDecryptionFailed, err.Error())
+		}
+
+		log.
+			WithField("attID", att.ID).
+			WithField("msgID", att.MessageID).
+			WithError(err).
+			Warn("Attachment decryption failed")
+
+		return writeCustomAttachmentPart(w, att, msg, err)
+	}
+
+	part, err := w.CreatePart(getAttachmentPartHeader(att))
+	if err != nil {
+		return err
+	}
+
+	if _, err := part.Write(dec.GetBinary()); err != nil {
+		return err
+	}
+
+	return part.Close()
+}
+
+func writeRelatedParts(
+	w *message.Writer,
+	kr *crypto.KeyRing,
+	boundary *boundary,
+	msg *pmapi.Message,
+	atts []*pmapi.Attachment,
+	attData [][]byte,
+	opts JobOptions,
+) error {
+	hdr := message.Header{}
+
+	hdr.SetContentType("multipart/related", map[string]string{"boundary": boundary.gen()})
+
+	rel, err := w.CreatePart(hdr)
+	if err != nil {
+		return err
+	}
+
+	if err := writeTextPart(rel, kr, msg, opts); err != nil {
+		return err
+	}
+
+	for i, att := range atts {
+		if err := writeAttachmentPart(rel, kr, att, attData[i], opts); err != nil {
+			return err
+		}
+	}
+
+	return rel.Close()
+}
+
+func buildEncryptedRFC822(kr *crypto.KeyRing, msg *pmapi.Message, opts JobOptions) ([]byte, error) {
+	hdr := getMessageHeader(msg, opts)
+
+	hdr.SetContentType("multipart/mixed", map[string]string{"boundary": newBoundary(msg.ID).gen()})
+
+	buf := new(bytes.Buffer)
+
+	w, err := message.CreateWriter(buf, hdr)
+	if err != nil {
+		return nil, err
+	}
+
+	dec, err := msg.Decrypt(kr)
+	if err != nil {
+		return nil, errors.Wrap(ErrDecryptionFailed, err.Error())
+	}
+
+	ent, err := message.Read(bytes.NewReader(dec))
+	if err != nil {
+		return nil, err
+	}
+
+	part, err := w.CreatePart(ent.Header)
+	if err != nil {
+		return nil, err
+	}
+
+	body, err := ioutil.ReadAll(ent.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err := part.Write(body); err != nil {
+		return nil, err
+	}
+
+	if err := part.Close(); err != nil {
+		return nil, err
+	}
+
+	if err := w.Close(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func getMessageHeader(msg *pmapi.Message, opts JobOptions) message.Header { // nolint[funlen]
+	hdr := toMessageHeader(msg.Header)
+
+	// SetText will RFC2047-encode.
+	if msg.Subject != "" {
+		hdr.SetText("Subject", msg.Subject)
+	}
+
+	// mail.Address.String() will RFC2047-encode if necessary.
+	if msg.Sender != nil {
+		hdr.Set("From", msg.Sender.String())
+	}
+
+	if len(msg.ReplyTos) > 0 {
+		hdr.Set("Reply-To", toAddressList(msg.ReplyTos))
+	}
+
+	if len(msg.ToList) > 0 {
+		hdr.Set("To", toAddressList(msg.ToList))
+	}
+
+	if len(msg.CCList) > 0 {
+		hdr.Set("Cc", toAddressList(msg.CCList))
+	}
+
+	if len(msg.BCCList) > 0 {
+		hdr.Set("Bcc", toAddressList(msg.BCCList))
+	}
+
+	setMessageIDIfNeeded(msg, &hdr)
+
+	// Sanitize the date; it needs to have a valid unix timestamp.
+	if opts.SanitizeDate {
+		if date, err := rfc5322.ParseDateTime(hdr.Get("Date")); err != nil || date.Before(time.Unix(0, 0)) {
+			msgDate := sanitizeMessageDate(msg.Time)
+			hdr.Set("Date", msgDate.In(time.UTC).Format(time.RFC1123Z))
+			// We clobbered the date so we save it under X-Original-Date.
+			hdr.Set("X-Original-Date", date.In(time.UTC).Format(time.RFC1123Z))
+		}
+	}
+
+	// Set our internal ID if requested.
+	// This is important for us to detect whether APPENDed things are actually "move like outlook".
+	if opts.AddInternalID {
+		hdr.Set("X-Pm-Internal-Id", msg.ID)
+	}
+
+	// Set our external ID if requested.
+	// This was useful during debugging of applemail recovered messages; doesn't help with any behaviour.
+	if opts.AddExternalID {
+		hdr.Set("X-Pm-External-Id", "<"+msg.ExternalID+">")
+	}
+
+	// Set our server date if requested.
+	// Can be useful to see how long it took for a message to arrive.
+	if opts.AddMessageDate {
+		hdr.Set("X-Pm-Date", time.Unix(msg.Time, 0).In(time.UTC).Format(time.RFC1123Z))
+	}
+
+	// Include the message ID in the references (supposedly this somehow improves outlook support...).
+	if opts.AddMessageIDReference {
+		if references := hdr.Get("References"); !strings.Contains(references, msg.ID) {
+			hdr.Set("References", references+" <"+msg.ID+"@"+pmapi.InternalIDDomain+">")
+		}
+	}
+
+	return hdr
+}
+
+// sanitizeMessageDate will return time from msgTime timestamp. If timestamp is
+// not after epoch the RFC822 publish day will be used. No message should
+// realistically be older than RFC822 itself.
+func sanitizeMessageDate(msgTime int64) time.Time {
+	if msgTime := time.Unix(msgTime, 0); msgTime.After(time.Unix(0, 0)) {
+		return msgTime
+	}
+	return time.Date(1982, 8, 13, 0, 0, 0, 0, time.UTC)
+}
+
+// setMessageIDIfNeeded sets Message-Id from ExternalID or ID if it's not
+// already set.
+func setMessageIDIfNeeded(msg *pmapi.Message, hdr *message.Header) {
+	if hdr.Get("Message-Id") == "" {
+		if msg.ExternalID != "" {
+			hdr.Set("Message-Id", "<"+msg.ExternalID+">")
+		} else {
+			hdr.Set("Message-Id", "<"+msg.ID+"@"+pmapi.InternalIDDomain+">")
+		}
+	}
+}
+
+func getTextPartHeader(hdr message.Header, body []byte, mimeType string) message.Header {
+	params := make(map[string]string)
+
+	if utf8.Valid(body) {
+		params["charset"] = "utf-8"
+	}
+
+	hdr.SetContentType(mimeType, params)
+
+	// Use quoted-printable for all text/... parts
+	hdr.Set("Content-Transfer-Encoding", "quoted-printable")
+
+	return hdr
+}
+
+func getAttachmentPartHeader(att *pmapi.Attachment) message.Header {
+	hdr := toMessageHeader(mail.Header(att.Header))
+
+	// All attachments have a content type.
+	hdr.SetContentType(att.MIMEType, map[string]string{"name": mime.QEncoding.Encode("utf-8", att.Name)})
+
+	// All attachments have a content disposition.
+	hdr.SetContentDisposition(att.Disposition, map[string]string{"filename": mime.QEncoding.Encode("utf-8", att.Name)})
+
+	// Use base64 for all attachments except embedded RFC822 messages.
+	if att.MIMEType != "message/rfc822" {
+		hdr.Set("Content-Transfer-Encoding", "base64")
+	} else {
+		hdr.Del("Content-Transfer-Encoding")
+	}
+
+	return hdr
+}
+
+func toMessageHeader(hdr mail.Header) message.Header {
+	var res message.Header
+
+	for key, val := range hdr {
+		for _, val := range val {
+			res.Add(key, val)
+		}
+	}
+
+	return res
+}
+
+func toAddressList(addrs []*mail.Address) string {
+	res := make([]string, len(addrs))
+
+	for i, addr := range addrs {
+		res[i] = addr.String()
+	}
+
+	return strings.Join(res, ", ")
+}

pkg/message/build_rfc822_custom.go

@@ -0,0 +1,97 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package message
+
+import (
+	"fmt"
+	"mime"
+
+	"github.com/ProtonMail/gopenpgp/v2/constants"
+	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
+	"github.com/emersion/go-message"
+)
+
+// writeCustomTextPart writes an armored-PGP text part for a message body that couldn't be decrypted.
+func writeCustomTextPart(
+	w *message.Writer,
+	msg *pmapi.Message,
+	decError error,
+) error {
+	enc, err := crypto.NewPGPMessageFromArmored(msg.Body)
+	if err != nil {
+		return err
+	}
+
+	arm, err := enc.GetArmoredWithCustomHeaders(
+		fmt.Sprintf("This message could not be decrypted: %v", decError),
+		constants.ArmorHeaderVersion,
+	)
+	if err != nil {
+		return err
+	}
+
+	var hdr message.Header
+
+	hdr.SetContentType(msg.MIMEType, nil)
+
+	part, err := w.CreatePart(hdr)
+	if err != nil {
+		return err
+	}
+
+	if _, err := part.Write([]byte(arm)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// writeCustomAttachmentPart writes an armored-PGP data part for an attachment that couldn't be decrypted.
+func writeCustomAttachmentPart(
+	w *message.Writer,
+	att *pmapi.Attachment,
+	msg *crypto.PGPMessage,
+	decError error,
+) error {
+	arm, err := msg.GetArmoredWithCustomHeaders(
+		fmt.Sprintf("This attachment could not be decrypted: %v", decError),
+		constants.ArmorHeaderVersion,
+	)
+	if err != nil {
+		return err
+	}
+
+	filename := mime.QEncoding.Encode("utf-8", att.Name+".pgp")
+
+	var hdr message.Header
+
+	hdr.SetContentType("application/octet-stream", map[string]string{"name": filename})
+	hdr.SetContentDisposition(att.Disposition, map[string]string{"filename": filename})
+
+	part, err := w.CreatePart(hdr)
+	if err != nil {
+		return err
+	}
+
+	if _, err := part.Write([]byte(arm)); err != nil {
+		return err
+	}
+
+	return part.Close()
+}

pkg/message/envelope.go

@@ -19,30 +19,49 @@ package message
 
 import (
 	"net/mail"
-	"time"
+	"net/textproto"
+	"strings"
 
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 	"github.com/emersion/go-imap"
 )
 
-func GetEnvelope(m *pmapi.Message) *imap.Envelope {
-	messageID := m.ExternalID
-	if messageID == "" {
-		messageID = m.Header.Get("Message-Id")
-	} else {
-		messageID = "<" + messageID + ">"
-	}
+// GetEnvelope will prepare envelope from pmapi message and cached header.
+func GetEnvelope(msg *pmapi.Message, header textproto.MIMEHeader) *imap.Envelope {
+	hdr := toMessageHeader(mail.Header(header))
+	setMessageIDIfNeeded(msg, &hdr)
 
 	return &imap.Envelope{
-		Date:      time.Unix(m.Time, 0),
-		Subject:   m.Subject,
-		From:      getAddresses([]*mail.Address{m.Sender}),
-		Sender:    getAddresses([]*mail.Address{m.Sender}),
-		ReplyTo:   getAddresses(m.ReplyTos),
-		To:        getAddresses(m.ToList),
-		Cc:        getAddresses(m.CCList),
-		Bcc:       getAddresses(m.BCCList),
-		InReplyTo: m.Header.Get("In-Reply-To"),
-		MessageId: messageID,
+		Date:      sanitizeMessageDate(msg.Time),
+		Subject:   msg.Subject,
+		From:      getAddresses([]*mail.Address{msg.Sender}),
+		Sender:    getAddresses([]*mail.Address{msg.Sender}),
+		ReplyTo:   getAddresses(msg.ReplyTos),
+		To:        getAddresses(msg.ToList),
+		Cc:        getAddresses(msg.CCList),
+		Bcc:       getAddresses(msg.BCCList),
+		InReplyTo: hdr.Get("In-Reply-To"),
+		MessageId: hdr.Get("Message-Id"),
 	}
 }
+
+func getAddresses(addrs []*mail.Address) (imapAddrs []*imap.Address) {
+	for _, a := range addrs {
+		if a == nil {
+			continue
+		}
+
+		parts := strings.SplitN(a.Address, "@", 2)
+		if len(parts) != 2 {
+			continue
+		}
+
+		imapAddrs = append(imapAddrs, &imap.Address{
+			PersonalName: a.Name,
+			MailboxName:  parts[0],
+			HostName:     parts[1],
+		})
+	}
+
+	return
+}

pkg/message/header.go

@@ -42,16 +42,16 @@ func GetHeader(msg *pmapi.Message) textproto.MIMEHeader { //nolint[funlen]
 		h.Set("From", pmmime.EncodeHeader(msg.Sender.String()))
 	}
 	if len(msg.ReplyTos) > 0 {
-		h.Set("Reply-To", pmmime.EncodeHeader(formatAddressList(msg.ReplyTos)))
+		h.Set("Reply-To", pmmime.EncodeHeader(toAddressList(msg.ReplyTos)))
 	}
 	if len(msg.ToList) > 0 {
-		h.Set("To", pmmime.EncodeHeader(formatAddressList(msg.ToList)))
+		h.Set("To", pmmime.EncodeHeader(toAddressList(msg.ToList)))
 	}
 	if len(msg.CCList) > 0 {
-		h.Set("Cc", pmmime.EncodeHeader(formatAddressList(msg.CCList)))
+		h.Set("Cc", pmmime.EncodeHeader(toAddressList(msg.CCList)))
 	}
 	if len(msg.BCCList) > 0 {
-		h.Set("Bcc", pmmime.EncodeHeader(formatAddressList(msg.BCCList)))
+		h.Set("Bcc", pmmime.EncodeHeader(toAddressList(msg.BCCList)))
 	}
 
 	// Add or rewrite date related fields.
@@ -91,7 +91,7 @@ func GetHeader(msg *pmapi.Message) textproto.MIMEHeader { //nolint[funlen]
 
 func SetBodyContentFields(h *textproto.MIMEHeader, m *pmapi.Message) {
 	h.Set("Content-Type", m.MIMEType+"; charset=utf-8")
-	h.Set("Content-Disposition", "inline")
+	h.Set("Content-Disposition", pmapi.DispositionInline)
 	h.Set("Content-Transfer-Encoding", "quoted-printable")
 }
 
@@ -101,27 +101,28 @@ func GetBodyHeader(m *pmapi.Message) textproto.MIMEHeader {
 	return h
 }
 
-func GetRelatedHeader(m *pmapi.Message) textproto.MIMEHeader {
-	h := make(textproto.MIMEHeader)
-	h.Set("Content-Type", "multipart/related; boundary="+GetRelatedBoundary(m))
-	return h
-}
-
-func GetAttachmentHeader(att *pmapi.Attachment) textproto.MIMEHeader {
+func GetAttachmentHeader(att *pmapi.Attachment, buildForIMAP bool) textproto.MIMEHeader {
 	mediaType := att.MIMEType
 	if mediaType == "application/pgp-encrypted" {
 		mediaType = "application/octet-stream"
 	}
 
+	transferEncoding := "base64"
+	if mediaType == rfc822Message && buildForIMAP {
+		transferEncoding = "8bit"
+	}
+
 	encodedName := pmmime.EncodeHeader(att.Name)
 	disposition := "attachment" //nolint[goconst]
-	if strings.Contains(att.Header.Get("Content-Disposition"), "inline") {
-		disposition = "inline"
+	if strings.Contains(att.Header.Get("Content-Disposition"), pmapi.DispositionInline) {
+		disposition = pmapi.DispositionInline
 	}
 
 	h := make(textproto.MIMEHeader)
 	h.Set("Content-Type", mime.FormatMediaType(mediaType, map[string]string{"name": encodedName}))
-	h.Set("Content-Transfer-Encoding", "base64")
+	if transferEncoding != "" {
+		h.Set("Content-Transfer-Encoding", transferEncoding)
+	}
 	h.Set("Content-Disposition", mime.FormatMediaType(disposition, map[string]string{"filename": encodedName}))
 
 	// Forward some original header lines.

pkg/message/message.go

@@ -18,31 +18,27 @@
 package message
 
 import (
-	"crypto/sha512"
-	"fmt"
 	"strings"
 
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 	"github.com/sirupsen/logrus"
 )
 
+const (
+	rfc822Message = "message/rfc822"
+)
+
 var log = logrus.WithField("pkg", "pkg/message") //nolint[gochecknoglobals]
 
 func GetBoundary(m *pmapi.Message) string {
 	// The boundary needs to be deterministic because messages are not supposed to
 	// change.
-	return fmt.Sprintf("%x", sha512.Sum512_256([]byte(m.ID)))
-}
-
-func GetRelatedBoundary(m *pmapi.Message) string {
-	// The boundary needs to be deterministic because messages are not supposed to
-	// change.
-	return fmt.Sprintf("%x", sha512.Sum512_256([]byte(m.ID+m.ID)))
+	return newBoundary(m.ID).gen()
 }
 
 func SeparateInlineAttachments(m *pmapi.Message) (atts, inlines []*pmapi.Attachment) {
 	for _, att := range m.Attachments {
-		if strings.Contains(att.Header.Get("Content-Disposition"), "inline") {
+		if strings.Contains(att.Header.Get("Content-Disposition"), pmapi.DispositionInline) {
 			inlines = append(inlines, att)
 		} else {
 			atts = append(atts, att)

pkg/message/mocks/mocks.go

@@ -0,0 +1,82 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: github.com/ProtonMail/proton-bridge/pkg/message (interfaces: Fetcher)
+
+// Package mocks is a generated GoMock package.
+package mocks
+
+import (
+	io "io"
+	reflect "reflect"
+
+	crypto "github.com/ProtonMail/gopenpgp/v2/crypto"
+	pmapi "github.com/ProtonMail/proton-bridge/pkg/pmapi"
+	gomock "github.com/golang/mock/gomock"
+)
+
+// MockFetcher is a mock of Fetcher interface
+type MockFetcher struct {
+	ctrl     *gomock.Controller
+	recorder *MockFetcherMockRecorder
+}
+
+// MockFetcherMockRecorder is the mock recorder for MockFetcher
+type MockFetcherMockRecorder struct {
+	mock *MockFetcher
+}
+
+// NewMockFetcher creates a new mock instance
+func NewMockFetcher(ctrl *gomock.Controller) *MockFetcher {
+	mock := &MockFetcher{ctrl: ctrl}
+	mock.recorder = &MockFetcherMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use
+func (m *MockFetcher) EXPECT() *MockFetcherMockRecorder {
+	return m.recorder
+}
+
+// GetAttachment mocks base method
+func (m *MockFetcher) GetAttachment(arg0 string) (io.ReadCloser, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "GetAttachment", arg0)
+	ret0, _ := ret[0].(io.ReadCloser)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// GetAttachment indicates an expected call of GetAttachment
+func (mr *MockFetcherMockRecorder) GetAttachment(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetAttachment", reflect.TypeOf((*MockFetcher)(nil).GetAttachment), arg0)
+}
+
+// GetMessage mocks base method
+func (m *MockFetcher) GetMessage(arg0 string) (*pmapi.Message, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "GetMessage", arg0)
+	ret0, _ := ret[0].(*pmapi.Message)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// GetMessage indicates an expected call of GetMessage
+func (mr *MockFetcherMockRecorder) GetMessage(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetMessage", reflect.TypeOf((*MockFetcher)(nil).GetMessage), arg0)
+}
+
+// KeyRingForAddressID mocks base method
+func (m *MockFetcher) KeyRingForAddressID(arg0 string) (*crypto.KeyRing, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "KeyRingForAddressID", arg0)
+	ret0, _ := ret[0].(*crypto.KeyRing)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// KeyRingForAddressID indicates an expected call of KeyRingForAddressID
+func (mr *MockFetcherMockRecorder) KeyRingForAddressID(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "KeyRingForAddressID", reflect.TypeOf((*MockFetcher)(nil).KeyRingForAddressID), arg0)
+}

pkg/message/parser.go

@@ -536,7 +536,7 @@ func parseAttachment(h message.Header) (*pmapi.Attachment, error) {
 	if h.Has("Content-Disposition") {
 		if disp, _, err := h.ContentDisposition(); err != nil {
 			return nil, err
-		} else if disp == "inline" {
+		} else if disp == pmapi.DispositionInline {
 			att.ContentID = strings.Trim(h.Get("Content-Id"), " <>")
 		}
 	} else if h.Has("Content-Id") {

pkg/message/section.go

@@ -38,7 +38,7 @@ type SectionInfo struct {
 	reader                    io.Reader
 }
 
-// Read and count
+// Read and count.
 func (si *SectionInfo) Read(p []byte) (n int, err error) {
 	n, err = si.reader.Read(p)
 	si.Size += n
@@ -237,11 +237,11 @@ func (bs *BodyStructure) parseAllChildSections(r io.Reader, currentPath []int, s
 	}
 
 	// Clear all buffers.
-	bodyReader = nil
+	bodyReader = nil //nolint[wastedassign] just to be sure we clear garbage collector
 	bodyInfo.reader = nil
 	tp.R = nil
-	tp = nil
-	bufInfo = nil // nolint
+	tp = nil      //nolint[wastedassign] just to be sure we clear garbage collector
+	bufInfo = nil //nolint[ineffassign] just to be sure we clear garbage collector
 	info.reader = nil
 
 	// Store boundaries.
@@ -305,6 +305,11 @@ func stringPathFromInts(ints []int) (ret string) {
 	return
 }
 
+func (bs *BodyStructure) hasInfo(sectionPath []int) bool {
+	_, err := bs.getInfo(sectionPath)
+	return err == nil
+}
+
 func (bs *BodyStructure) getInfo(sectionPath []int) (sectionInfo *SectionInfo, err error) {
 	path := stringPathFromInts(sectionPath)
 	sectionInfo, ok := (*bs)[path]
@@ -332,30 +337,40 @@ func (bs *BodyStructure) GetSectionContent(wholeMail io.ReadSeeker, sectionPath
 	if err != nil {
 		return
 	}
-	if _, err = wholeMail.Seek(int64(info.Start+info.Size-info.BSize), io.SeekStart); err != nil {
-		return
-	}
-	section = make([]byte, info.BSize)
-	_, err = wholeMail.Read(section)
-	return
+	return goToOffsetAndReadNBytes(wholeMail, info.Start+info.Size-info.BSize, info.BSize)
+}
 
-	/* This is slow:
-	sectionBuf, err := bs.GetSection(wholeMail, sectionPath)
+// GetMailHeader returns the main header of mail.
+func (bs *BodyStructure) GetMailHeader() (header textproto.MIMEHeader, err error) {
+	return bs.GetSectionHeader([]int{})
+}
+
+// GetMailHeaderBytes returns the bytes with main mail header.
+// Warning: It can contain extra lines or multipart comment.
+func (bs *BodyStructure) GetMailHeaderBytes(wholeMail io.ReadSeeker) (header []byte, err error) {
+	info, err := bs.getInfo([]int{})
 	if err != nil {
 		return
 	}
-
-	tp := textproto.NewReader(bufio.NewReader(buf))
-	if _, err = tp.ReadMIMEHeader(); err != nil {
-		return err
-	}
-
-	sectionBuf = &bytes.Buffer{}
-	_, err = io.Copy(sectionBuf, tp.R)
-	return
-	*/
+	headerLength := info.Size - info.BSize
+	return goToOffsetAndReadNBytes(wholeMail, 0, headerLength)
 }
 
+func goToOffsetAndReadNBytes(wholeMail io.ReadSeeker, offset, length int) ([]byte, error) {
+	if length < 1 {
+		return nil, errors.New("requested non positive length")
+	}
+	if offset > 0 {
+		if _, err := wholeMail.Seek(int64(offset), io.SeekStart); err != nil {
+			return nil, err
+		}
+	}
+	out := make([]byte, length)
+	_, err := wholeMail.Read(out)
+	return out, err
+}
+
+// GetSectionHeader returns the mime header of specified section.
 func (bs *BodyStructure) GetSectionHeader(sectionPath []int) (header textproto.MIMEHeader, err error) {
 	info, err := bs.getInfo(sectionPath)
 	if err != nil {
@@ -404,7 +419,7 @@ func (bs *BodyStructure) IMAPBodyStructure(currentPart []int) (imapBS *imap.Body
 
 	nextPart := append(currentPart, 1)
 	for {
-		if _, err := bs.getInfo(nextPart); err != nil {
+		if !bs.hasInfo(nextPart) {
 			break
 		}
 		var subStruct *imap.BodyStructure

pkg/message/section_test.go

@@ -108,6 +108,24 @@ func TestGetSection(t *testing.T) {
 	}
 }
 
+func TestGetMainHeaderBytes(t *testing.T) {
+	wantHeader := []byte(`Subject: Sample mail
+From: John Doe <jdoe@machine.example>
+To: Mary Smith <mary@example.net>
+Date: Fri, 21 Nov 1997 09:55:06 -0600
+Content-Type: multipart/mixed; boundary="0000MAIN"
+
+`)
+
+	structReader := strings.NewReader(sampleMail)
+	bs, err := NewBodyStructure(structReader)
+	require.NoError(t, err)
+
+	haveHeader, err := bs.GetMailHeaderBytes(strings.NewReader(sampleMail))
+	require.NoError(t, err)
+	require.Equal(t, wantHeader, haveHeader)
+}
+
 /* Structure example:
 HEADER     ([RFC-2822] header of the message)
 TEXT       ([RFC-2822] text body of the message) MULTIPART/MIXED

pkg/message/testdata/pgp-mime-body-html.eml

@@ -0,0 +1,33 @@
+Content-Type: multipart/mixed; boundary="u5NoTcx3NkhqapFjjYFKJZdxCaEWvrsGw";
+ protected-headers="v1"
+Subject: html no pubkey no sign
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <c38ad850-0916-e290-ee1c-326c3ff9fb5f@gmail.com>
+
+--u5NoTcx3NkhqapFjjYFKJZdxCaEWvrsGw
+Content-Type: text/html; charset=utf-8
+Content-Language: en-US
+Content-Transfer-Encoding: quoted-printable
+
+<html>
+  <head>
+
+    <meta http-equiv=3D"content-type" content=3D"text/html; charset=3DUTF=
+-8">
+  </head>
+  <body>
+    <ul>
+      <li><i>What do you call a poor Santa Claus?</i> <b>St.
+          Nickel-less.</b></li>
+      <li><i>Where do boats go when they're sick?</i> <b>To the boat
+          doc.</b><br>
+      </li>
+    </ul>
+    <p><br>
+    </p>
+  </body>
+</html>
+
+
+--u5NoTcx3NkhqapFjjYFKJZdxCaEWvrsGw--

pkg/message/testdata/pgp-mime-body-plaintext.eml

@@ -0,0 +1,17 @@
+Content-Type: multipart/mixed; boundary="unlHEst6hn6dMAzATXJvy5dCLgUfF9Vvs";
+ protected-headers="v1"
+Subject: plain no pubkey no sign
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <564b9c7c-91eb-6508-107a-35108f383a44@gmail.com>
+
+--unlHEst6hn6dMAzATXJvy5dCLgUfF9Vvs
+Content-Type: text/plain; charset=utf-8; format=flowed
+Content-Transfer-Encoding: quoted-printable
+Content-Language: en-US
+
+Where do fruits go on vacation? Pear-is!
+
+
+
+--unlHEst6hn6dMAzATXJvy5dCLgUfF9Vvs--

pkg/message/testdata/pgp-mime-body-signed-embedded-message-rfc822-with-pubkey.eml

@@ -0,0 +1,212 @@
+Content-Type: multipart/signed; micalg=pgp-sha256;
+ protocol="application/pgp-signature";
+ boundary="Rrmlds5vN3IeeCVjbnepHmuVgyROSBjsS"
+
+This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
+--Rrmlds5vN3IeeCVjbnepHmuVgyROSBjsS
+Content-Type: multipart/mixed; boundary="avFkF0LAPYPXcFHcnsgGmACbGIPeVDdYc";
+ protected-headers="v1"
+Subject: Fwd: HTML with attachment external PGP
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <7c04869b-c470-116f-b8e5-8b4fd5e1195d@gmail.com>
+References: <LCxIUvb0rqBufdwR4JNxMg4ZDMI8x7pRG0vEHGHYwA@cp7-web-042.plabs.ch>
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+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
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+ZVfwhtJeFsmdqSm6DLvCmQWAYk2fDOZDMVKqe9IbUA==
+=pkS0
+-----END PGP SIGNATURE-----
+
+--pavrbLYh8Q4RWBboYnVxY3mNBBzan1Zz4--

pkg/message/testdata/pgp-mime-body-signed-html.eml

@@ -0,0 +1,58 @@
+Content-Type: multipart/signed; micalg=pgp-sha256;
+ protocol="application/pgp-signature";
+ boundary="YxKjBoCQD3a9PdAWo8ztsilFlSghrT8M5"
+
+This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
+--YxKjBoCQD3a9PdAWo8ztsilFlSghrT8M5
+Content-Type: multipart/mixed; boundary="6GLjuOzexqUw1CoA6CFjmA6r51g9FOPK7";
+ protected-headers="v1"
+Subject: html body no pubkey
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <5e22f83a-c4f0-d61a-55c8-8230854dc052@gmail.com>
+
+--6GLjuOzexqUw1CoA6CFjmA6r51g9FOPK7
+Content-Type: text/html; charset=utf-8
+Content-Language: en-US
+Content-Transfer-Encoding: quoted-printable
+
+<html>
+  <head>
+
+    <meta http-equiv=3D"content-type" content=3D"text/html; charset=3DUTF=
+-8">
+  </head>
+  <body>
+    Behold another <font color=3D"#ee24cc">HTML</font><br>
+    <ul>
+      <li><b>I only know 25 letters of the alphabet.</b> <b>I don't
+          know y.</b></li>
+      <li><b>What did one wall say to the other?</b><i> I'll meet you at
+          the corner.</i></li>
+      <li><b>What did the zero say to the eight?</b> <i>Damn, that belt
+          looks good on you.</i><br>
+      </li>
+    </ul>
+  </body>
+</html>
+
+
+--6GLjuOzexqUw1CoA6CFjmA6r51g9FOPK7--
+
+--YxKjBoCQD3a9PdAWo8ztsilFlSghrT8M5
+Content-Type: application/pgp-signature; name="OpenPGP_signature.asc"
+Content-Description: OpenPGP digital signature
+Content-Disposition: attachment; filename="OpenPGP_signature"
+
+-----BEGIN PGP SIGNATURE-----
+
+wsB5BAABCAAjFiEEXOYJeXAvKFvzKPmxFhwIdYIjWfcFAmBa+RsFAwAAAAAACgkQFhwIdYIjWfcK
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+IEKAzLTy6nYnVltYkFC1ggwAVouq4o6Bcw/5bUt2fA==
+=lk/3
+-----END PGP SIGNATURE-----
+
+--YxKjBoCQD3a9PdAWo8ztsilFlSghrT8M5--

pkg/message/testdata/pgp-mime-body-signed-multipart-alternative-with-pubkey.eml

@@ -0,0 +1,161 @@
+Content-Type: multipart/signed; micalg=pgp-sha256;
+ protocol="application/pgp-signature";
+ boundary="MHEDFShwcX18dyE3X7RXujo5fjpgdjHNM"
+
+This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
+--MHEDFShwcX18dyE3X7RXujo5fjpgdjHNM
+Content-Type: multipart/mixed; boundary="FBBl2LNv76z8UkvHhSkT9vLwVwxqV8378";
+ protected-headers="v1"
+Subject: Alternative
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <753d0314-0286-2c88-2abb-f8080ac7a4cb@gmail.com>
+
+--FBBl2LNv76z8UkvHhSkT9vLwVwxqV8378
+Content-Type: multipart/mixed;
+ boundary="------------F97C8ED4878E94675762AE43"
+Content-Language: en-US
+
+This is a multi-part message in MIME format.
+--------------F97C8ED4878E94675762AE43
+Content-Type: multipart/alternative;
+ boundary="------------041318B15DD3FA540FED32C6"
+
+
+--------------041318B15DD3FA540FED32C6
+Content-Type: text/plain; charset=utf-8; format=flowed
+Content-Transfer-Encoding: quoted-printable
+
+This Rich formated text
+
+  * /What kind of shoes do ninjas wear? /*Sneakers!*
+  * /How does a penguin build its house?/**_/*Igloos it together.*/_
+
+
+
+
+--------------041318B15DD3FA540FED32C6
+Content-Type: text/html; charset=utf-8
+Content-Transfer-Encoding: quoted-printable
+
+<html>
+  <head>
+
+    <meta http-equiv=3D"content-type" content=3D"text/html; charset=3DUTF=
+-8">
+  </head>
+  <body>
+    <p>This <font color=3D"#ee24cc">Rich</font> formated text</p>
+    <ul>
+      <li><i>What kind of shoes do ninjas wear? </i><b>Sneakers!</b></li>=
+
+      <li><i>How does a penguin build its house?</i><b> </b><u><i><b>Iglo=
+os
+              it together.</b></i></u></li>
+    </ul>
+    <p><br>
+    </p>
+    <p><br>
+    </p>
+  </body>
+</html>
+
+--------------041318B15DD3FA540FED32C6--
+
+--------------F97C8ED4878E94675762AE43
+Content-Type: application/pdf;
+ name="minimal.pdf"
+Content-Transfer-Encoding: base64
+Content-Disposition: attachment;
+ filename="minimal.pdf"
+
+JVBERi0xLjEKJcKlwrHDqwoKMSAwIG9iagogIDw8IC9UeXBlIC9DYXRhbG9nCiAgICAgL1Bh
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+--------------F97C8ED4878E94675762AE43
+Content-Type: application/pgp-keys;
+ name="OpenPGP_0x161C0875822359F7.asc"
+Content-Transfer-Encoding: quoted-printable
+Content-Disposition: attachment;
+ filename="OpenPGP_0x161C0875822359F7.asc"
+
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+
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+=3Dv/1p
+-----END PGP PUBLIC KEY BLOCK-----
+
+--------------F97C8ED4878E94675762AE43--
+
+--FBBl2LNv76z8UkvHhSkT9vLwVwxqV8378--
+
+--MHEDFShwcX18dyE3X7RXujo5fjpgdjHNM
+Content-Type: application/pgp-signature; name="OpenPGP_signature.asc"
+Content-Description: OpenPGP digital signature
+Content-Disposition: attachment; filename="OpenPGP_signature"
+
+-----BEGIN PGP SIGNATURE-----
+
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+=Bc6p
+-----END PGP SIGNATURE-----
+
+--MHEDFShwcX18dyE3X7RXujo5fjpgdjHNM--

pkg/message/testdata/pgp-mime-body-signed-plaintext-with-pubkey.eml

@@ -0,0 +1,103 @@
+Content-Type: multipart/signed; micalg=pgp-sha256;
+ protocol="application/pgp-signature";
+ boundary="x4FrOFG2PnNJvlbzxe80NPwxzh2yUHABp"
+
+This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
+--x4FrOFG2PnNJvlbzxe80NPwxzh2yUHABp
+Content-Type: multipart/mixed; boundary="bBln6dwDJTLkin5LPHkHBQudqRLwIzTUH";
+ protected-headers="v1"
+Subject: simple plaintext body
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <adb5ac5d-b8f6-c9a3-5cc0-0fb2e9677512@gmail.com>
+
+--bBln6dwDJTLkin5LPHkHBQudqRLwIzTUH
+Content-Type: multipart/mixed;
+ boundary="------------1B34C666A4C2FB03E0324F1A"
+Content-Language: en-US
+
+This is a multi-part message in MIME format.
+--------------1B34C666A4C2FB03E0324F1A
+Content-Type: text/plain; charset=utf-8; format=flowed
+Content-Transfer-Encoding: quoted-printable
+
+Why don't crabs give to charity? Because they're shellfish.
+
+
+
+--------------1B34C666A4C2FB03E0324F1A
+Content-Type: application/pgp-keys;
+ name="OpenPGP_0x161C0875822359F7.asc"
+Content-Transfer-Encoding: quoted-printable
+Content-Disposition: attachment;
+ filename="OpenPGP_0x161C0875822359F7.asc"
+
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+
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+-----END PGP PUBLIC KEY BLOCK-----
+
+--------------1B34C666A4C2FB03E0324F1A--
+
+--bBln6dwDJTLkin5LPHkHBQudqRLwIzTUH--
+
+--x4FrOFG2PnNJvlbzxe80NPwxzh2yUHABp
+Content-Type: application/pgp-signature; name="OpenPGP_signature.asc"
+Content-Description: OpenPGP digital signature
+Content-Disposition: attachment; filename="OpenPGP_signature"
+
+-----BEGIN PGP SIGNATURE-----
+
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+=hUb8
+-----END PGP SIGNATURE-----
+
+--x4FrOFG2PnNJvlbzxe80NPwxzh2yUHABp--

pkg/message/testdata/pgp-mime-body-signed-plaintext.eml

@@ -0,0 +1,43 @@
+Content-Type: multipart/signed; micalg=pgp-sha256;
+ protocol="application/pgp-signature";
+ boundary="M2HYr2fNKsmidMKeWqsSlKJaGCe2l1guZ"
+
+This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
+--M2HYr2fNKsmidMKeWqsSlKJaGCe2l1guZ
+Content-Type: multipart/mixed; boundary="ijQgYCMAVOgOyTMqn30h68dd5lQKbMzCn";
+ protected-headers="v1"
+Subject: plain body no pubkey
+From: "pm.bridge.qa" <pm.bridge.qa@gmail.com>
+To: schizofrenic@pm.me
+Message-ID: <7414d726-2f14-54bf-3abe-75805aa6cc7f@gmail.com>
+
+--ijQgYCMAVOgOyTMqn30h68dd5lQKbMzCn
+Content-Type: text/plain; charset=utf-8; format=flowed
+Content-Transfer-Encoding: quoted-printable
+Content-Language: en-US
+
+Why do seagulls fly over the ocean?
+
+Because if they flew over the bay, we'd call them bagels.
+
+
+
+--ijQgYCMAVOgOyTMqn30h68dd5lQKbMzCn--
+
+--M2HYr2fNKsmidMKeWqsSlKJaGCe2l1guZ
+Content-Type: application/pgp-signature; name="OpenPGP_signature.asc"
+Content-Description: OpenPGP digital signature
+Content-Disposition: attachment; filename="OpenPGP_signature"
+
+-----BEGIN PGP SIGNATURE-----
+
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+-----END PGP SIGNATURE-----
+
+--M2HYr2fNKsmidMKeWqsSlKJaGCe2l1guZ--