1 files changed, 58 insertions, 0 deletions
diff --git a/modules/charset/escape.go b/modules/charset/escape.go
new file mode 100644
index 0000000..ba0eb73
--- /dev/null
+++ b/modules/charset/escape.go
@@ -0,0 +1,58 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:generate go run invisible/generate.go -v -o ./invisible_gen.go
+
+//go:generate go run ambiguous/generate.go -v -o ./ambiguous_gen.go ambiguous/ambiguous.json
+
+package charset
+
+import (
+	"html/template"
+	"io"
+	"slices"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/translation"
+)
+
+// RuneNBSP is the codepoint for NBSP
+const RuneNBSP = 0xa0
+
+type escapeContext string
+
+// Keep this consistent with the documentation of [ui].SKIP_ESCAPE_CONTEXTS
+// Defines the different contexts that could be used to escape in.
+const (
+	// Wiki pages.
+	WikiContext escapeContext = "wiki"
+	// Rendered content (except markup), source code and blames.
+	FileviewContext escapeContext = "file-view"
+	// Commits or pull requet's diff.
+	DiffContext escapeContext = "diff"
+)
+
+// EscapeControlHTML escapes the unicode control sequences in a provided html document
+func EscapeControlHTML(html template.HTML, locale translation.Locale, context escapeContext, allowed ...rune) (escaped *EscapeStatus, output template.HTML) {
+	sb := &strings.Builder{}
+	escaped, _ = EscapeControlReader(strings.NewReader(string(html)), sb, locale, context, allowed...) // err has been handled in EscapeControlReader
+	return escaped, template.HTML(sb.String())
+}
+
+// EscapeControlReader escapes the unicode control sequences in a provided reader of HTML content and writer in a locale and returns the findings as an EscapeStatus
+func EscapeControlReader(reader io.Reader, writer io.Writer, locale translation.Locale, context escapeContext, allowed ...rune) (escaped *EscapeStatus, err error) {
+	if !setting.UI.AmbiguousUnicodeDetection || slices.Contains(setting.UI.SkipEscapeContexts, string(context)) {
+		_, err = io.Copy(writer, reader)
+		return &EscapeStatus{}, err
+	}
+	outputStream := &HTMLStreamerWriter{Writer: writer}
+	streamer := NewEscapeStreamer(locale, outputStream, allowed...).(*escapeStreamer)
+
+	if err = StreamHTML(reader, streamer); err != nil {
+		streamer.escaped.HasError = true
+		log.Error("Error whilst escaping: %v", err)
+	}
+	return streamer.escaped, err
+}