forked from gitea/gitea
60 lines
1.8 KiB
Go
60 lines
1.8 KiB
Go
// Copyright 2023 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package svg
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import (
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"bytes"
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"fmt"
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"regexp"
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"sync"
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)
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type normalizeVarsStruct struct {
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reXMLDoc,
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reComment,
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reAttrXMLNs,
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reAttrSize,
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reAttrClassPrefix *regexp.Regexp
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}
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var (
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normalizeVars *normalizeVarsStruct
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normalizeVarsOnce sync.Once
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)
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// Normalize normalizes the SVG content: set default width/height, remove unnecessary tags/attributes
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// It's designed to work with valid SVG content. For invalid SVG content, the returned content is not guaranteed.
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func Normalize(data []byte, size int) []byte {
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normalizeVarsOnce.Do(func() {
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normalizeVars = &normalizeVarsStruct{
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reXMLDoc: regexp.MustCompile(`(?s)<\?xml.*?>`),
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reComment: regexp.MustCompile(`(?s)<!--.*?-->`),
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reAttrXMLNs: regexp.MustCompile(`(?s)\s+xmlns\s*=\s*"[^"]*"`),
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reAttrSize: regexp.MustCompile(`(?s)\s+(width|height)\s*=\s*"[^"]+"`),
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reAttrClassPrefix: regexp.MustCompile(`(?s)\s+class\s*=\s*"`),
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}
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})
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data = normalizeVars.reXMLDoc.ReplaceAll(data, nil)
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data = normalizeVars.reComment.ReplaceAll(data, nil)
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data = bytes.TrimSpace(data)
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svgTag, svgRemaining, ok := bytes.Cut(data, []byte(">"))
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if !ok || !bytes.HasPrefix(svgTag, []byte(`<svg`)) {
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return data
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}
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normalized := bytes.Clone(svgTag)
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normalized = normalizeVars.reAttrXMLNs.ReplaceAll(normalized, nil)
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normalized = normalizeVars.reAttrSize.ReplaceAll(normalized, nil)
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normalized = normalizeVars.reAttrClassPrefix.ReplaceAll(normalized, []byte(` class="`))
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normalized = bytes.TrimSpace(normalized)
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normalized = fmt.Appendf(normalized, ` width="%d" height="%d"`, size, size)
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if !bytes.Contains(normalized, []byte(` class="`)) {
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normalized = append(normalized, ` class="svg"`...)
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}
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normalized = append(normalized, '>')
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normalized = append(normalized, svgRemaining...)
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return normalized
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}
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