forked from Silverfish/proton-bridge
82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
// Copyright (c) 2024 Proton AG
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//
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// This file is part of Proton Mail Bridge.
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//
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// Proton Mail 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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// Proton Mail 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 Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
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package parser
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import "regexp"
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type Visitor struct {
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root *Part
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rules []*visitorRule
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defaultRule VisitorRule
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}
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func newVisitor(root *Part, defaultRule VisitorRule) *Visitor {
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return &Visitor{
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root: root,
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defaultRule: defaultRule,
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}
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}
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type Visit func(*Part) (interface{}, error)
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type VisitorRule func(*Part, Visit) (interface{}, error)
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type visitorRule struct {
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re *regexp.Regexp
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fn VisitorRule
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}
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// RegisterRule defines what to do when visiting a part whose content type
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// matches the given regular expression.
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// If a part matches multiple rules, the one registered first will be used.
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func (v *Visitor) RegisterRule(contentTypeRegex string, fn VisitorRule) *Visitor {
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v.rules = append(v.rules, &visitorRule{
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re: regexp.MustCompile(contentTypeRegex),
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fn: fn,
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})
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return v
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}
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func (v *Visitor) Visit() (interface{}, error) {
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return v.visit(v.root)
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}
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func (v *Visitor) visit(p *Part) (interface{}, error) {
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t, _, err := p.ContentType()
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if err != nil {
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return nil, err
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}
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if rule := v.getRuleForContentType(t); rule != nil {
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return rule.fn(p, v.visit)
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}
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return v.defaultRule(p, v.visit)
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}
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func (v *Visitor) getRuleForContentType(contentType string) *visitorRule {
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for _, rule := range v.rules {
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if rule.re.MatchString(contentType) {
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return rule
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}
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}
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return nil
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}
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