1 files changed, 31 insertions, 24 deletions

diff --git a/libgo/go/encoding/json/encode.go b/libgo/go/encoding/json/encode.go
index dea63f1..464ee3e 100644
--- a/libgo/go/encoding/json/encode.go
+++ b/libgo/go/encoding/json/encode.go
@@ -45,11 +45,12 @@ import (
 //
 // String values encode as JSON strings coerced to valid UTF-8,
 // replacing invalid bytes with the Unicode replacement rune.
-// The angle brackets "<" and ">" are escaped to "\u003c" and "\u003e"
-// to keep some browsers from misinterpreting JSON output as HTML.
-// Ampersand "&" is also escaped to "\u0026" for the same reason.
-// This escaping can be disabled using an Encoder that had SetEscapeHTML(false)
-// called on it.
+// So that the JSON will be safe to embed inside HTML <script> tags,
+// the string is encoded using HTMLEscape,
+// which replaces "<", ">", "&", U+2028, and U+2029 are escaped
+// to "\u003c","\u003e", "\u0026", "\u2028", and "\u2029".
+// This replacement can be disabled when using an Encoder,
+// by calling SetEscapeHTML(false).
 //
 // Array and slice values encode as JSON arrays, except that
 // []byte encodes as a base64-encoded string, and a nil slice
@@ -269,6 +270,8 @@ func (e *MarshalerError) Error() string {
 	return "json: error calling MarshalJSON for type " + e.Type.String() + ": " + e.Err.Error()
 }
 
+func (e *MarshalerError) Unwrap() error { return e.Err }
+
 var hex = "0123456789abcdef"
 
 // An encodeState encodes JSON into a bytes.Buffer.
@@ -392,19 +395,15 @@ func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
 	if t.Implements(marshalerType) {
 		return marshalerEncoder
 	}
-	if t.Kind() != reflect.Ptr && allowAddr {
-		if reflect.PtrTo(t).Implements(marshalerType) {
-			return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
-		}
+	if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(marshalerType) {
+		return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
 	}
 
 	if t.Implements(textMarshalerType) {
 		return textMarshalerEncoder
 	}
-	if t.Kind() != reflect.Ptr && allowAddr {
-		if reflect.PtrTo(t).Implements(textMarshalerType) {
-			return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
-		}
+	if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(textMarshalerType) {
+		return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
 	}
 
 	switch t.Kind() {
@@ -625,14 +624,19 @@ func unsupportedTypeEncoder(e *encodeState, v reflect.Value, _ encOpts) {
 }
 
 type structEncoder struct {
-	fields []field
+	fields structFields
+}
+
+type structFields struct {
+	list      []field
+	nameIndex map[string]int
 }
 
 func (se structEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 	next := byte('{')
 FieldLoop:
-	for i := range se.fields {
-		f := &se.fields[i]
+	for i := range se.fields.list {
+		f := &se.fields.list[i]
 
 		// Find the nested struct field by following f.index.
 		fv := v
@@ -1067,14 +1071,13 @@ func (x byIndex) Less(i, j int) bool {
 // typeFields returns a list of fields that JSON should recognize for the given type.
 // The algorithm is breadth-first search over the set of structs to include - the top struct
 // and then any reachable anonymous structs.
-func typeFields(t reflect.Type) []field {
+func typeFields(t reflect.Type) structFields {
 	// Anonymous fields to explore at the current level and the next.
 	current := []field{}
 	next := []field{{typ: t}}
 
 	// Count of queued names for current level and the next.
-	count := map[reflect.Type]int{}
-	nextCount := map[reflect.Type]int{}
+	var count, nextCount map[reflect.Type]int
 
 	// Types already visited at an earlier level.
 	visited := map[reflect.Type]bool{}
@@ -1242,7 +1245,11 @@ func typeFields(t reflect.Type) []field {
 		f := &fields[i]
 		f.encoder = typeEncoder(typeByIndex(t, f.index))
 	}
-	return fields
+	nameIndex := make(map[string]int, len(fields))
+	for i, field := range fields {
+		nameIndex[field.name] = i
+	}
+	return structFields{fields, nameIndex}
 }
 
 // dominantField looks through the fields, all of which are known to
@@ -1261,13 +1268,13 @@ func dominantField(fields []field) (field, bool) {
 	return fields[0], true
 }
 
-var fieldCache sync.Map // map[reflect.Type][]field
+var fieldCache sync.Map // map[reflect.Type]structFields
 
 // cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
-func cachedTypeFields(t reflect.Type) []field {
+func cachedTypeFields(t reflect.Type) structFields {
 	if f, ok := fieldCache.Load(t); ok {
-		return f.([]field)
+		return f.(structFields)
 	}
 	f, _ := fieldCache.LoadOrStore(t, typeFields(t))
-	return f.([]field)
+	return f.(structFields)
 }