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gitea/modules/svg/processor.go

60 lines
1.8 KiB
Go

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