Support map<k,v> protocol buffer fields.
diff --git a/proto/encode.go b/proto/encode.go
index cc202cd..f5050e3 100644
--- a/proto/encode.go
+++ b/proto/encode.go
@@ -1069,6 +1069,104 @@
return sizeExtensionMap(v)
}
+// Encode a map field.
+func (o *Buffer) enc_new_map(p *Properties, base structPointer) error {
+ var state errorState // XXX: or do we need to plumb this through?
+
+ /*
+ A map defined as
+ map<key_type, value_type> map_field = N;
+ is encoded in the same way as
+ message MapFieldEntry {
+ key_type key = 1;
+ value_type value = 2;
+ }
+ repeated MapFieldEntry map_field = N;
+ */
+
+ v := structPointer_Map(base, p.field, p.mtype).Elem() // map[K]V
+ if v.Len() == 0 {
+ return nil
+ }
+
+ keycopy, valcopy, keybase, valbase := mapEncodeScratch(p.mtype)
+
+ enc := func() error {
+ if err := p.mkeyprop.enc(o, p.mkeyprop, keybase); err != nil {
+ return err
+ }
+ if err := p.mvalprop.enc(o, p.mvalprop, valbase); err != nil {
+ return err
+ }
+ return nil
+ }
+
+ for _, key := range v.MapKeys() {
+ val := v.MapIndex(key)
+
+ keycopy.Set(key)
+ valcopy.Set(val)
+
+ o.buf = append(o.buf, p.tagcode...)
+ if err := o.enc_len_thing(enc, &state); err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+func size_new_map(p *Properties, base structPointer) int {
+ v := structPointer_Map(base, p.field, p.mtype).Elem() // map[K]V
+
+ keycopy, valcopy, keybase, valbase := mapEncodeScratch(p.mtype)
+
+ n := 0
+ for _, key := range v.MapKeys() {
+ val := v.MapIndex(key)
+ keycopy.Set(key)
+ valcopy.Set(val)
+
+ // Tag codes are two bytes per map entry.
+ n += 2
+ n += p.mkeyprop.size(p.mkeyprop, keybase)
+ n += p.mvalprop.size(p.mvalprop, valbase)
+ }
+ return n
+}
+
+// mapEncodeScratch returns a new reflect.Value matching the map's value type,
+// and a structPointer suitable for passing to an encoder or sizer.
+func mapEncodeScratch(mapType reflect.Type) (keycopy, valcopy reflect.Value, keybase, valbase structPointer) {
+ // Prepare addressable doubly-indirect placeholders for the key and value types.
+ // This is needed because the element-type encoders expect **T, but the map iteration produces T.
+
+ keycopy = reflect.New(mapType.Key()).Elem() // addressable K
+ keyptr := reflect.New(reflect.PtrTo(keycopy.Type())).Elem() // addressable *K
+ keyptr.Set(keycopy.Addr()) //
+ keybase = toStructPointer(keyptr.Addr()) // **K
+
+ // Value types are more varied and require special handling.
+ switch mapType.Elem().Kind() {
+ case reflect.Slice:
+ // []byte
+ var dummy []byte
+ valcopy = reflect.ValueOf(&dummy).Elem() // addressable []byte
+ valbase = toStructPointer(valcopy.Addr())
+ case reflect.Ptr:
+ // message; the generated field type is map[K]*Msg (so V is *Msg),
+ // so we only need one level of indirection.
+ valcopy = reflect.New(mapType.Elem()).Elem() // addressable V
+ valbase = toStructPointer(valcopy.Addr())
+ default:
+ // everything else
+ valcopy = reflect.New(mapType.Elem()).Elem() // addressable V
+ valptr := reflect.New(reflect.PtrTo(valcopy.Type())).Elem() // addressable *V
+ valptr.Set(valcopy.Addr()) //
+ valbase = toStructPointer(valptr.Addr()) // **V
+ }
+ return
+}
+
// Encode a struct.
func (o *Buffer) enc_struct(prop *StructProperties, base structPointer) error {
var state errorState
@@ -1123,10 +1221,15 @@
// Encode a struct, preceded by its encoded length (as a varint).
func (o *Buffer) enc_len_struct(prop *StructProperties, base structPointer, state *errorState) error {
+ return o.enc_len_thing(func() error { return o.enc_struct(prop, base) }, state)
+}
+
+// Encode something, preceded by its encoded length (as a varint).
+func (o *Buffer) enc_len_thing(enc func() error, state *errorState) error {
iLen := len(o.buf)
o.buf = append(o.buf, 0, 0, 0, 0) // reserve four bytes for length
iMsg := len(o.buf)
- err := o.enc_struct(prop, base)
+ err := enc()
if err != nil && !state.shouldContinue(err, nil) {
return err
}