1 files changed, 43 insertions, 0 deletions
diff --git a/modules/charset/breakwriter.go b/modules/charset/breakwriter.go
new file mode 100644
index 0000000..a87e846
--- /dev/null
+++ b/modules/charset/breakwriter.go
@@ -0,0 +1,43 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package charset
+
+import (
+	"bytes"
+	"io"
+)
+
+// BreakWriter wraps an io.Writer to always write '\n' as '<br>'
+type BreakWriter struct {
+	io.Writer
+}
+
+// Write writes the provided byte slice transparently replacing '\n' with '<br>'
+func (b *BreakWriter) Write(bs []byte) (n int, err error) {
+	pos := 0
+	for pos < len(bs) {
+		idx := bytes.IndexByte(bs[pos:], '\n')
+		if idx < 0 {
+			wn, err := b.Writer.Write(bs[pos:])
+			return n + wn, err
+		}
+
+		if idx > 0 {
+			wn, err := b.Writer.Write(bs[pos : pos+idx])
+			n += wn
+			if err != nil {
+				return n, err
+			}
+		}
+
+		if _, err = b.Writer.Write([]byte("<br>")); err != nil {
+			return n, err
+		}
+		pos += idx + 1
+
+		n++
+	}
+
+	return n, err
+}