feat: custom address/date parser based on rfc5322 abnf

pkg/message/rfc5322/parser.go

@@ -0,0 +1,83 @@
+// Copyright (c) 2020 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 rfc5322
+
+import (
+	"net/mail"
+	"time"
+
+	"github.com/ProtonMail/proton-bridge/pkg/message/rfc5322/parser"
+	"github.com/antlr/antlr4/runtime/Go/antlr"
+	"github.com/sirupsen/logrus"
+)
+
+// ParseAddressList parses one or more valid RFC5322 (with RFC2047) addresses.
+func ParseAddressList(input string) ([]*mail.Address, error) {
+	if len(input) == 0 {
+		return []*mail.Address{}, nil
+	}
+
+	l := parser.NewRFC5322Lexer(antlr.NewInputStream(input))
+	p := parser.NewRFC5322Parser(antlr.NewCommonTokenStream(l, antlr.TokenDefaultChannel))
+	w := &walker{}
+
+	p.AddErrorListener(w)
+	p.AddParseListener(&parseListener{rules: p.GetRuleNames()})
+
+	antlr.ParseTreeWalkerDefault.Walk(w, p.AddressList())
+
+	return w.res.([]*mail.Address), w.err
+}
+
+// ParseDateTime parses a valid RFC5322 date-time.
+func ParseDateTime(input string) (time.Time, error) {
+	if len(input) == 0 {
+		return time.Time{}, nil
+	}
+
+	l := parser.NewRFC5322Lexer(antlr.NewInputStream(input))
+	p := parser.NewRFC5322Parser(antlr.NewCommonTokenStream(l, antlr.TokenDefaultChannel))
+	w := &walker{}
+
+	p.AddErrorListener(w)
+	p.AddParseListener(&parseListener{rules: p.GetRuleNames()})
+
+	antlr.ParseTreeWalkerDefault.Walk(w, p.DateTime())
+
+	return w.res.(time.Time), w.err
+}
+
+type parseListener struct {
+	antlr.BaseParseTreeListener
+
+	rules []string
+}
+
+func (l *parseListener) EnterEveryRule(ctx antlr.ParserRuleContext) {
+	logrus.
+		WithField("rule", l.rules[ctx.GetRuleIndex()]).
+		WithField("text", ctx.GetText()).
+		Trace("Entering rule")
+}
+
+func (l *parseListener) ExitEveryRule(ctx antlr.ParserRuleContext) {
+	logrus.
+		WithField("rule", l.rules[ctx.GetRuleIndex()]).
+		WithField("text", ctx.GetText()).
+		Trace("Exiting rule")
+}