update doc, add tests

docs/content/administration/customizing-gitea.en-us.md

@@ -388,6 +388,7 @@ It could add theme meta information into the custom theme CSS file to provide mo
 
 If a custom theme is a dark theme, please set the global css variable `--is-dark-theme: true` in the `:root` block.
 This allows Gitea to adjust the Monaco code editor's theme accordingly.
+An "auto" theme could be implemented by using "theme-gitea-auto.css" as a reference.
 
 ```css
 gitea-theme-meta-info {

services/webtheme/webtheme.go

@@ -49,7 +49,11 @@ func parseThemeMetaInfoToMap(cssContent string) map[string]string {
 (
 \s*(--[-\w]+)
 \s*:
-\s*("(\\"|[^"])*")
+\s*(
+("(\\"|[^"])*")
+|('(\\'|[^'])*')
+|([^'";]+)
+)
 \s*;
 \s*
 )
@@ -66,9 +70,13 @@ func parseThemeMetaInfoToMap(cssContent string) map[string]string {
 	m := map[string]string{}
 	for _, item := range matchedItems {
 		v := item[3]
-		v = strings.TrimPrefix(v, "\"")
+		if strings.HasPrefix(v, `"`) {
-		v = strings.TrimSuffix(v, "\"")
+			v = strings.TrimSuffix(strings.TrimPrefix(v, `"`), `"`)
 			v = strings.ReplaceAll(v, `\"`, `"`)
+		} else if strings.HasPrefix(v, `'`) {
+			v = strings.TrimSuffix(strings.TrimPrefix(v, `'`), `'`)
+			v = strings.ReplaceAll(v, `\'`, `'`)
+		}
 		m[item[2]] = v
 	}
 	return m

services/webtheme/webtheme_test.go

@@ -10,6 +10,28 @@ import (
 )
 
 func TestParseThemeMetaInfo(t *testing.T) {
-	m := parseThemeMetaInfoToMap(`gitea-theme-meta-info { --k1: "v1"; --k2: "a\"b"; }`)
+	m := parseThemeMetaInfoToMap(`gitea-theme-meta-info {
-	assert.Equal(t, map[string]string{"--k1": "v1", "--k2": `a"b`}, m)
+	--k1: "v1";
+	--k2: "v\"2";
+	--k3: 'v3';
+	--k4: 'v\'4';
+	--k5: v5;
+}`)
+	assert.Equal(t, map[string]string{
+		"--k1": "v1",
+		"--k2": `v"2`,
+		"--k3": "v3",
+		"--k4": "v'4",
+		"--k5": "v5",
+	}, m)
+
+	// if an auto theme imports others, the meta info should be extracted from the last one
+	// the meta in imported themes should be ignored to avoid incorrect overriding
+	m = parseThemeMetaInfoToMap(`
+@media (prefers-color-scheme: dark) { gitea-theme-meta-info { --k1: foo; } }
+@media (prefers-color-scheme: dark) { gitea-theme-meta-info { --k1: bar; } }
+gitea-theme-meta-info {
+	--k2: real;
+}`)
+	assert.Equal(t, map[string]string{"--k2": "real"}, m)
 }