mirror of
https://github.com/ProtonMail/proton-bridge.git
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63 lines
2.0 KiB
Go
63 lines
2.0 KiB
Go
// Copyright (c) 2020 Proton Technologies AG
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//
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// This file is part of ProtonMail Bridge.
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//
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// ProtonMail Bridge is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// ProtonMail Bridge is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with ProtonMail Bridge. If not, see <https://www.gnu.org/licenses/>.
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package rfc5322
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import (
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"fmt"
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"github.com/ProtonMail/proton-bridge/pkg/message/rfc5322/parser"
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"github.com/antlr/antlr4/runtime/Go/antlr"
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)
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// walker implements parser.BaseRFC5322ParserListener, defining what to do at
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// each node while traversing the syntax tree.
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// It also implements antlr.DefaultErrorListener, allowing us to react to
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// errors encountered while trying to determine the syntax tree of the input.
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type walker struct {
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parser.BaseRFC5322ParserListener
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antlr.DefaultErrorListener
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// nodes acts as a stack; when entering a node, it is pushed here, and when
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// exiting a node, it is popped from here.
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nodes []interface{}
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// res holds the result of walking the parse tree.
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res interface{}
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// err holds the error encountered during parsing, if any.
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err error
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}
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func (w *walker) enter(b interface{}) {
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w.nodes = append(w.nodes, b)
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}
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func (w *walker) exit() interface{} {
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b := w.nodes[len(w.nodes)-1]
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w.nodes = w.nodes[:len(w.nodes)-1]
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return b
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}
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func (w *walker) parent() (b interface{}) {
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return w.nodes[len(w.nodes)-1]
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}
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func (w *walker) SyntaxError(_ antlr.Recognizer, _ interface{}, _, _ int, msg string, _ antlr.RecognitionException) {
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w.err = fmt.Errorf("error parsing rfc5322 input: %v", msg)
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}
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