refactor: remove go-appdir dependency

internal/app/base/base.go

@@ -35,7 +35,6 @@ import (
 	"runtime/pprof"
 
 	"github.com/Masterminds/semver/v3"
-	"github.com/ProtonMail/go-appdir"
 	"github.com/ProtonMail/go-autostart"
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
 	"github.com/ProtonMail/proton-bridge/internal/api"
@@ -99,10 +98,12 @@ func New( // nolint[funlen]
 	)
 	defer crashHandler.HandlePanic()
 
-	locations := locations.New(
-		appdir.New(filepath.Join(constants.VendorName, configName)),
-		configName,
-	)
+	locationsProvider, err := locations.NewDefaultProvider(filepath.Join(constants.VendorName, configName))
+	if err != nil {
+		return nil, err
+	}
+
+	locations := locations.New(locationsProvider, configName)
 	if err := locations.Clean(); err != nil {
 		return nil, err
 	}

internal/app/base/migration.go

@@ -21,7 +21,6 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/ProtonMail/go-appdir"
 	"github.com/ProtonMail/proton-bridge/internal/constants"
 	"github.com/ProtonMail/proton-bridge/internal/locations"
 	"github.com/sirupsen/logrus"
@@ -35,10 +34,13 @@ import (
 // | prefs  | ~/.cache/protonmail/<app>/c11/prefs.json  | ~/.config/protonmail/<app>/prefs.json  |
 // | c11    | ~/.cache/protonmail/<app>/c11             | ~/.cache/protonmail/<app>/cache/c11    |
 func MigrateFiles(configName string) error {
-	appDirs := appdir.New(filepath.Join(constants.VendorName, configName))
-	locations := locations.New(appDirs, configName)
+	locationsProvider, err := locations.NewDefaultProvider(filepath.Join(constants.VendorName, configName))
+	if err != nil {
+		return err
+	}
 
-	userCacheDir := appDirs.UserCache()
+	locations := locations.New(locationsProvider, configName)
+	userCacheDir := locationsProvider.UserCache()
 	newSettingsDir, err := locations.ProvideSettingsPath()
 	if err != nil {
 		return err

internal/locations/locations.go

@@ -40,15 +40,11 @@ type Locations struct {
 	configName            string
 }
 
-type appDirsProvider interface {
-	UserConfig() string
-	UserCache() string
-}
-
-func New(appDirs appDirsProvider, configName string) *Locations {
+// New returns a new locations object.
+func New(provider Provider, configName string) *Locations {
 	return &Locations{
-		userConfig: appDirs.UserConfig(),
-		userCache:  appDirs.UserCache(),
+		userConfig: provider.UserConfig(),
+		userCache:  provider.UserCache(),
 		configName: configName,
 	}
 }

internal/locations/provider.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 locations
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// Provider provides standard locations.
+type Provider interface {
+	UserConfig() string
+	UserCache() string
+}
+
+// DefaultProvider is a locations provider using the system-default storage locations.
+type DefaultProvider struct {
+	config, cache string
+}
+
+func NewDefaultProvider(name string) (*DefaultProvider, error) {
+	config, err := os.UserConfigDir()
+	if err != nil {
+		return nil, err
+	}
+
+	cache, err := os.UserCacheDir()
+	if err != nil {
+		return nil, err
+	}
+
+	return &DefaultProvider{
+		config: filepath.Join(config, name),
+		cache:  filepath.Join(cache, name),
+	}, nil
+}
+
+func (p *DefaultProvider) UserConfig() string {
+	return p.config
+}
+
+func (p *DefaultProvider) UserCache() string {
+	return p.cache
+}