v0.0.415 add 'tagkey' to gojson.Decoder

gojson/encode.go

@@ -382,7 +382,12 @@ func isEmptyValue(v reflect.Value) bool {
 }
 
 func (e *encodeState) reflectValue(v reflect.Value, opts encOpts) {
-	valueEncoder(v)(e, v, opts)
+	tagkey := "json"
+	if opts.tagkey != nil {
+		tagkey = *opts.tagkey
+	}
+
+	valueEncoder(v, tagkey)(e, v, opts)
 }
 
 type encOpts struct {
@@ -397,20 +402,22 @@ type encOpts struct {
 	// filter matches jsonfilter tag of struct
 	// marshals if no jsonfilter is set or otherwise if jsonfilter has the filter value
 	filter *string
+	// use different tag instead of "json"
+	tagkey *string
 }
 
 type encoderFunc func(e *encodeState, v reflect.Value, opts encOpts)
 
 var encoderCache sync.Map // map[reflect.Type]encoderFunc
 
-func valueEncoder(v reflect.Value) encoderFunc {
+func valueEncoder(v reflect.Value, tagkey string) encoderFunc {
 	if !v.IsValid() {
 		return invalidValueEncoder
 	}
-	return typeEncoder(v.Type())
+	return typeEncoder(v.Type(), tagkey)
 }
 
-func typeEncoder(t reflect.Type) encoderFunc {
+func typeEncoder(t reflect.Type, tagkey string) encoderFunc {
 	if fi, ok := encoderCache.Load(t); ok {
 		return fi.(encoderFunc)
 	}
@@ -433,7 +440,7 @@ func typeEncoder(t reflect.Type) encoderFunc {
 	}
 
 	// Compute the real encoder and replace the indirect func with it.
-	f = newTypeEncoder(t, true)
+	f = newTypeEncoder(t, true, tagkey)
 	wg.Done()
 	encoderCache.Store(t, f)
 	return f
@@ -446,19 +453,19 @@ var (
 
 // newTypeEncoder constructs an encoderFunc for a type.
 // The returned encoder only checks CanAddr when allowAddr is true.
-func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
+func newTypeEncoder(t reflect.Type, allowAddr bool, tagkey string) encoderFunc {
 	// If we have a non-pointer value whose type implements
 	// Marshaler with a value receiver, then we're better off taking
 	// the address of the value - otherwise we end up with an
 	// allocation as we cast the value to an interface.
 	if t.Kind() != reflect.Pointer && allowAddr && reflect.PointerTo(t).Implements(marshalerType) {
-		return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
+		return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false, tagkey))
 	}
 	if t.Implements(marshalerType) {
 		return marshalerEncoder
 	}
 	if t.Kind() != reflect.Pointer && allowAddr && reflect.PointerTo(t).Implements(textMarshalerType) {
-		return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
+		return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false, tagkey))
 	}
 	if t.Implements(textMarshalerType) {
 		return textMarshalerEncoder
@@ -480,15 +487,15 @@ func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
 	case reflect.Interface:
 		return interfaceEncoder
 	case reflect.Struct:
-		return newStructEncoder(t)
+		return newStructEncoder(t, tagkey)
 	case reflect.Map:
-		return newMapEncoder(t)
+		return newMapEncoder(t, tagkey)
 	case reflect.Slice:
-		return newSliceEncoder(t)
+		return newSliceEncoder(t, tagkey)
 	case reflect.Array:
-		return newArrayEncoder(t)
+		return newArrayEncoder(t, tagkey)
 	case reflect.Pointer:
-		return newPtrEncoder(t)
+		return newPtrEncoder(t, tagkey)
 	default:
 		return unsupportedTypeEncoder
 	}
@@ -801,8 +808,8 @@ FieldLoop:
 	}
 }
 
-func newStructEncoder(t reflect.Type) encoderFunc {
-	se := structEncoder{fields: cachedTypeFields(t)}
+func newStructEncoder(t reflect.Type, tagkey string) encoderFunc {
+	se := structEncoder{fields: cachedTypeFields(t, tagkey)}
 	return se.encode
 }
 
@@ -855,7 +862,7 @@ func (me mapEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 	e.ptrLevel--
 }
 
-func newMapEncoder(t reflect.Type) encoderFunc {
+func newMapEncoder(t reflect.Type, tagkey string) encoderFunc {
 	switch t.Key().Kind() {
 	case reflect.String,
 		reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
@@ -865,7 +872,7 @@ func newMapEncoder(t reflect.Type) encoderFunc {
 			return unsupportedTypeEncoder
 		}
 	}
-	me := mapEncoder{typeEncoder(t.Elem())}
+	me := mapEncoder{typeEncoder(t.Elem(), tagkey)}
 	return me.encode
 }
 
@@ -936,7 +943,7 @@ func (se sliceEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 	e.ptrLevel--
 }
 
-func newSliceEncoder(t reflect.Type) encoderFunc {
+func newSliceEncoder(t reflect.Type, tagkey string) encoderFunc {
 	// Byte slices get special treatment; arrays don't.
 	if t.Elem().Kind() == reflect.Uint8 {
 		p := reflect.PointerTo(t.Elem())
@@ -944,7 +951,7 @@ func newSliceEncoder(t reflect.Type) encoderFunc {
 			return encodeByteSlice
 		}
 	}
-	enc := sliceEncoder{newArrayEncoder(t)}
+	enc := sliceEncoder{newArrayEncoder(t, tagkey)}
 	return enc.encode
 }
 
@@ -964,8 +971,8 @@ func (ae arrayEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 	e.WriteByte(']')
 }
 
-func newArrayEncoder(t reflect.Type) encoderFunc {
-	enc := arrayEncoder{typeEncoder(t.Elem())}
+func newArrayEncoder(t reflect.Type, tagkey string) encoderFunc {
+	enc := arrayEncoder{typeEncoder(t.Elem(), tagkey)}
 	return enc.encode
 }
 
@@ -992,8 +999,8 @@ func (pe ptrEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 	e.ptrLevel--
 }
 
-func newPtrEncoder(t reflect.Type) encoderFunc {
-	enc := ptrEncoder{typeEncoder(t.Elem())}
+func newPtrEncoder(t reflect.Type, tagkey string) encoderFunc {
+	enc := ptrEncoder{typeEncoder(t.Elem(), tagkey)}
 	return enc.encode
 }
 
@@ -1270,7 +1277,7 @@ 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) structFields {
+func typeFields(t reflect.Type, tagkey string) structFields {
 	// Anonymous fields to explore at the current level and the next.
 	current := []field{}
 	next := []field{{typ: t}}
@@ -1315,7 +1322,7 @@ func typeFields(t reflect.Type) structFields {
 					// Ignore unexported non-embedded fields.
 					continue
 				}
-				tag := sf.Tag.Get("json")
+				tag := sf.Tag.Get(tagkey)
 				if tag == "-" {
 					continue
 				}
@@ -1449,7 +1456,7 @@ func typeFields(t reflect.Type) structFields {
 
 	for i := range fields {
 		f := &fields[i]
-		f.encoder = typeEncoder(typeByIndex(t, f.index))
+		f.encoder = typeEncoder(typeByIndex(t, f.index), tagkey)
 	}
 	nameIndex := make(map[string]int, len(fields))
 	for i, field := range fields {
@@ -1474,13 +1481,26 @@ func dominantField(fields []field) (field, bool) {
 	return fields[0], true
 }
 
-var fieldCache sync.Map // map[reflect.Type]structFields
+var fieldCache sync.Map // map[string]map[reflect.Type]structFields
 
 // cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
-func cachedTypeFields(t reflect.Type) structFields {
-	if f, ok := fieldCache.Load(t); ok {
+func cachedTypeFields(t reflect.Type, tagkey string) structFields {
+	if m0, ok := fieldCache.Load(tagkey); ok {
+
+		if f, ok := m0.(*sync.Map).Load(t); ok {
+			return f.(structFields)
+		}
+		f, _ := m0.(*sync.Map).LoadOrStore(t, typeFields(t, tagkey))
+		return f.(structFields)
+
+	} else {
+
+		m0 := &sync.Map{}
+		f, _ := m0.LoadOrStore(t, typeFields(t, tagkey))
+
+		fieldCache.Store(tagkey, m0)
+
 		return f.(structFields)
 	}
-	f, _ := fieldCache.LoadOrStore(t, typeFields(t))
-	return f.(structFields)
+
 }