Refactor backend SVG package and add tests (#26335)

Introduce a well-tested `svg.Normalize` function.
Make `RenderHTML` faster and more stable.

diff --git a/modules/html/html.go b/modules/html/html.go
index 6cb6b847ef19cd2588aa98ab12515f4ae3ccb3a0..b1ebd584c6b6dbc7dc9be668ae528720035956dc 100644 (file)
--- a/modules/html/html.go
+++ b/modules/html/html.go
@@ -6,28 +6,20 @@ package html
 // ParseSizeAndClass get size and class from string with default values
 // If present, "others" expects the new size first and then the classes to use
 func ParseSizeAndClass(defaultSize int, defaultClass string, others ...any) (int, string) {
-       if len(others) == 0 {
-               return defaultSize, defaultClass
-       }
-
        size := defaultSize
-       _size, ok := others[0].(int)
-       if ok && _size != 0 {
-               size = _size
-       }
-
-       if len(others) == 1 {
-               return size, defaultClass
+       if len(others) >= 1 {
+               if v, ok := others[0].(int); ok && v != 0 {
+                       size = v
+               }
        }
-
        class := defaultClass
-       if _class, ok := others[1].(string); ok && _class != "" {
-               if defaultClass == "" {
-                       class = _class
-               } else {
-                       class = defaultClass + " " + _class
+       if len(others) >= 2 {
+               if v, ok := others[1].(string); ok && v != "" {
+                       if class != "" {
+                               class += " "
+                       }
+                       class += v
                }
        }
-
        return size, class
 }

diff --git a/modules/svg/processor.go b/modules/svg/processor.go
new file mode 100644 (file)
index 0000000..82248fb
--- /dev/null
+++ b/modules/svg/processor.go
@@ -0,0 +1,59 @@
+// 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
+}

diff --git a/modules/svg/processor_test.go b/modules/svg/processor_test.go
new file mode 100644 (file)
index 0000000..a028666
--- /dev/null
+++ b/modules/svg/processor_test.go
@@ -0,0 +1,29 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package svg
+
+import (
+       "testing"
+
+       "github.com/stretchr/testify/assert"
+)
+
+func TestNormalize(t *testing.T) {
+       res := Normalize([]byte("foo"), 1)
+       assert.Equal(t, "foo", string(res))
+
+       res = Normalize([]byte(`<?xml version="1.0"?>
+<!--
+comment
+-->
+<svg xmlns = "...">content</svg>`), 1)
+       assert.Equal(t, `<svg width="1" height="1" class="svg">content</svg>`, string(res))
+
+       res = Normalize([]byte(`<svg
+width="100"
+class="svg-icon"
+>content</svg>`), 16)
+
+       assert.Equal(t, `<svg class="svg-icon" width="16" height="16">content</svg>`, string(res))
+}

diff --git a/modules/svg/svg.go b/modules/svg/svg.go
index fc96ea8e6abdcfa57c894c56abb5422d0a255aa6..016e1dc08bb3489834e6ff2a331ebcb7f8d2040f 100644 (file)
--- a/modules/svg/svg.go
+++ b/modules/svg/svg.go
@@ -7,42 +7,35 @@ import (
        "fmt"
        "html/template"
        "path"
-       "regexp"
        "strings"
 
-       "code.gitea.io/gitea/modules/html"
+       gitea_html "code.gitea.io/gitea/modules/html"
        "code.gitea.io/gitea/modules/log"
        "code.gitea.io/gitea/modules/public"
 )
 
-var (
-       // SVGs contains discovered SVGs
-       SVGs = map[string]string{}
-
-       widthRe  = regexp.MustCompile(`width="[0-9]+?"`)
-       heightRe = regexp.MustCompile(`height="[0-9]+?"`)
-)
+var svgIcons map[string]string
 
 const defaultSize = 16
 
-// Init discovers SVGs and populates the `SVGs` variable
+// Init discovers SVG icons and populates the `svgIcons` variable
 func Init() error {
-       files, err := public.AssetFS().ListFiles("assets/img/svg")
+       const svgAssetsPath = "assets/img/svg"
+       files, err := public.AssetFS().ListFiles(svgAssetsPath)
        if err != nil {
                return err
        }
 
-       // Remove `xmlns` because inline SVG does not need it
-       reXmlns := regexp.MustCompile(`(<svg\b[^>]*?)\s+xmlns="[^"]*"`)
+       svgIcons = make(map[string]string, len(files))
        for _, file := range files {
                if path.Ext(file) != ".svg" {
                        continue
                }
-               bs, err := public.AssetFS().ReadFile("assets/img/svg", file)
+               bs, err := public.AssetFS().ReadFile(svgAssetsPath, file)
                if err != nil {
                        log.Error("Failed to read SVG file %s: %v", file, err)
                } else {
-                       SVGs[file[:len(file)-4]] = reXmlns.ReplaceAllString(string(bs), "$1")
+                       svgIcons[file[:len(file)-4]] = string(Normalize(bs, defaultSize))
                }
        }
        return nil
@@ -50,12 +43,12 @@ func Init() error {
 
 // RenderHTML renders icons - arguments icon name (string), size (int), class (string)
 func RenderHTML(icon string, others ...any) template.HTML {
-       size, class := html.ParseSizeAndClass(defaultSize, "", others...)
-
-       if svgStr, ok := SVGs[icon]; ok {
+       size, class := gitea_html.ParseSizeAndClass(defaultSize, "", others...)
+       if svgStr, ok := svgIcons[icon]; ok {
+               // the code is somewhat hacky, but it just works, because the SVG contents are all normalized
                if size != defaultSize {
-                       svgStr = widthRe.ReplaceAllString(svgStr, fmt.Sprintf(`width="%d"`, size))
-                       svgStr = heightRe.ReplaceAllString(svgStr, fmt.Sprintf(`height="%d"`, size))
+                       svgStr = strings.Replace(svgStr, fmt.Sprintf(`width="%d"`, defaultSize), fmt.Sprintf(`width="%d"`, size), 1)
+                       svgStr = strings.Replace(svgStr, fmt.Sprintf(`height="%d"`, defaultSize), fmt.Sprintf(`height="%d"`, size), 1)
                }
                if class != "" {
                        svgStr = strings.Replace(svgStr, `class="`, fmt.Sprintf(`class="%s `, class), 1)