code review 5707054: encoding/json: escape output from Marshalers.

src/pkg/encoding/json/indent.go

 // Copyright 2010 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package json
 
 import "bytes"
 
 // Compact appends to dst the JSON-encoded src with
 // insignificant space characters elided.
 func Compact(dst *bytes.Buffer, src []byte) error {
+        return compact(dst, src, false)
+}
+
+func compact(dst *bytes.Buffer, src []byte, escape bool) error {
         origLen := dst.Len()
         var scan scanner
         scan.reset()
         start := 0
         for i, c := range src {
+                if escape && (c == '<' || c == '>' || c == '&') {
+                        if start < i {
+                                dst.Write(src[start:i])
+                        }
+                        dst.WriteString(`\u00`)
+                        dst.WriteByte(hex[c>>4])
+                        dst.WriteByte(hex[c&0xF])
+                        start = i + 1
+                }
                 v := scan.step(&scan, int(c))
                 if v >= scanSkipSpace {
                         if v == scanError {
                                 break
                         }
                         if start < i {
                                 dst.Write(src[start:i])
                         }
                         start = i + 1
                 }
@@ skipping 78 matching lines @@
                 default:
                         dst.WriteByte(c)
                 }
         }
         if scan.eof() == scanError {
                 dst.Truncate(origLen)
                 return scan.err
         }
         return nil
 }