proto, runtime/protoiface, internal/impl: add fast-path Merge
Comparing -tags=protoreflect to fast-path:
name old time/op new time/op delta
pkg:google.golang.org/protobuf/internal/benchmarks goos:linux goarch:amd64
/Clone/google_message1_proto2-12 1.70µs ± 1% 0.30µs ± 1% -82.64% (p=0.001 n=7+7)
/Clone/google_message1_proto3-12 1.01µs ± 1% 0.19µs ± 1% -80.77% (p=0.000 n=7+8)
/Clone/google_message2-12 818µs ± 8% 141µs ± 6% -82.78% (p=0.000 n=8+8)
pkg:google.golang.org/protobuf/internal/benchmarks/micro goos:linux goarch:amd64
EmptyMessage/Clone-12 51.1ns ± 1% 39.3ns ± 3% -23.03% (p=0.000 n=7+8)
RepeatedInt32/Clone-12 24.5µs ± 1% 1.1µs ± 3% -95.64% (p=0.000 n=8+8)
Required/Clone-12 978ns ± 1% 132ns ± 2% -86.46% (p=0.000 n=8+8)
name old alloc/op new alloc/op delta
pkg:google.golang.org/protobuf/internal/benchmarks goos:linux goarch:amd64
/Clone/google_message1_proto2-12 1.08kB ± 0% 0.74kB ± 0% -31.85% (p=0.000 n=8+8)
/Clone/google_message1_proto3-12 872B ± 0% 544B ± 0% -37.61% (p=0.000 n=8+8)
/Clone/google_message2-12 602kB ± 0% 411kB ± 0% -31.65% (p=0.000 n=8+8)
pkg:google.golang.org/protobuf/internal/benchmarks/micro goos:linux goarch:amd64
EmptyMessage/Clone-12 96.0B ± 0% 64.0B ± 0% -33.33% (p=0.000 n=8+8)
RepeatedInt32/Clone-12 25.4kB ± 0% 3.2kB ± 0% -87.33% (p=0.000 n=8+8)
Required/Clone-12 416B ± 0% 256B ± 0% -38.46% (p=0.000 n=8+8)
name old allocs/op new allocs/op delta
pkg:google.golang.org/protobuf/internal/benchmarks goos:linux goarch:amd64
/Clone/google_message1_proto2-12 52.0 ± 0% 21.0 ± 0% -59.62% (p=0.000 n=8+8)
/Clone/google_message1_proto3-12 33.0 ± 0% 3.0 ± 0% -90.91% (p=0.000 n=8+8)
/Clone/google_message2-12 22.3k ± 0% 7.5k ± 0% -66.41% (p=0.000 n=8+8)
pkg:google.golang.org/protobuf/internal/benchmarks/micro goos:linux goarch:amd64
EmptyMessage/Clone-12 3.00 ± 0% 2.00 ± 0% -33.33% (p=0.000 n=8+8)
RepeatedInt32/Clone-12 1.51k ± 0% 0.00k ± 0% -99.80% (p=0.000 n=8+8)
Required/Clone-12 51.0 ± 0% 18.0 ± 0% -64.71% (p=0.000 n=8+8)
Change-Id: Ife9018097c34cb025dc9c4fdd9a61b2f947853c6
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/219147
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
diff --git a/internal/impl/merge.go b/internal/impl/merge.go
new file mode 100644
index 0000000..20d9dfd
--- /dev/null
+++ b/internal/impl/merge.go
@@ -0,0 +1,176 @@
+// Copyright 2020 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 impl
+
+import (
+ "fmt"
+ "reflect"
+
+ "google.golang.org/protobuf/proto"
+ pref "google.golang.org/protobuf/reflect/protoreflect"
+ piface "google.golang.org/protobuf/runtime/protoiface"
+)
+
+type mergeOptions piface.MergeOptions
+
+func (o mergeOptions) Merge(dst, src proto.Message) {
+ proto.Merge(dst, src)
+}
+
+// merge is protoreflect.Methods.Merge.
+func (mi *MessageInfo) merge(dst, src pref.Message, in piface.MergeInput, opts piface.MergeOptions) piface.MergeOutput {
+ dp, ok := mi.getPointer(dst)
+ if !ok {
+ return piface.MergeOutput{Merged: false}
+ }
+ sp, ok := mi.getPointer(src)
+ if !ok {
+ return piface.MergeOutput{Merged: false}
+ }
+ mi.mergePointer(dp, sp, opts)
+ return piface.MergeOutput{Merged: true}
+}
+
+func (mi *MessageInfo) mergePointer(dst, src pointer, opts mergeOptions) {
+ mi.init()
+ if dst.IsNil() {
+ panic(fmt.Sprintf("invalid value: merging into nil message"))
+ }
+ if src.IsNil() {
+ return
+ }
+ for _, f := range mi.orderedCoderFields {
+ if f.funcs.merge == nil {
+ continue
+ }
+ sfptr := src.Apply(f.offset)
+ if f.isPointer && sfptr.Elem().IsNil() {
+ continue
+ }
+ f.funcs.merge(dst.Apply(f.offset), sfptr, f, opts)
+ }
+ if mi.extensionOffset.IsValid() {
+ sext := src.Apply(mi.extensionOffset).Extensions()
+ dext := dst.Apply(mi.extensionOffset).Extensions()
+ if *dext == nil {
+ *dext = make(map[int32]ExtensionField)
+ }
+ for num, sx := range *sext {
+ xt := sx.Type()
+ xi := getExtensionFieldInfo(xt)
+ if xi.funcs.merge == nil {
+ continue
+ }
+ dx := (*dext)[num]
+ var dv pref.Value
+ if dx.Type() == sx.Type() {
+ dv = dx.Value()
+ }
+ if !dv.IsValid() && xi.unmarshalNeedsValue {
+ dv = xt.New()
+ }
+ dv = xi.funcs.merge(dv, sx.Value(), opts)
+ dx.Set(sx.Type(), dv)
+ (*dext)[num] = dx
+ }
+ }
+ if mi.unknownOffset.IsValid() {
+ du := dst.Apply(mi.unknownOffset).Bytes()
+ su := src.Apply(mi.unknownOffset).Bytes()
+ if len(*su) > 0 {
+ *du = append(*du, *su...)
+ }
+ }
+}
+
+func mergeScalarValue(dst, src pref.Value, opts mergeOptions) pref.Value {
+ return src
+}
+
+func mergeBytesValue(dst, src pref.Value, opts mergeOptions) pref.Value {
+ return pref.ValueOfBytes(append(emptyBuf[:], src.Bytes()...))
+}
+
+func mergeListValue(dst, src pref.Value, opts mergeOptions) pref.Value {
+ dstl := dst.List()
+ srcl := src.List()
+ for i, llen := 0, srcl.Len(); i < llen; i++ {
+ dstl.Append(srcl.Get(i))
+ }
+ return dst
+}
+
+func mergeBytesListValue(dst, src pref.Value, opts mergeOptions) pref.Value {
+ dstl := dst.List()
+ srcl := src.List()
+ for i, llen := 0, srcl.Len(); i < llen; i++ {
+ sb := srcl.Get(i).Bytes()
+ db := append(emptyBuf[:], sb...)
+ dstl.Append(pref.ValueOfBytes(db))
+ }
+ return dst
+}
+
+func mergeMessageListValue(dst, src pref.Value, opts mergeOptions) pref.Value {
+ dstl := dst.List()
+ srcl := src.List()
+ for i, llen := 0, srcl.Len(); i < llen; i++ {
+ sm := srcl.Get(i).Message()
+ dm := proto.Clone(sm.Interface()).ProtoReflect()
+ dstl.Append(pref.ValueOfMessage(dm))
+ }
+ return dst
+}
+
+func mergeMessageValue(dst, src pref.Value, opts mergeOptions) pref.Value {
+ opts.Merge(dst.Message().Interface(), src.Message().Interface())
+ return dst
+}
+
+func mergeMessage(dst, src pointer, f *coderFieldInfo, opts mergeOptions) {
+ if f.mi != nil {
+ if dst.Elem().IsNil() {
+ dst.SetPointer(pointerOfValue(reflect.New(f.mi.GoReflectType.Elem())))
+ }
+ f.mi.mergePointer(dst.Elem(), src.Elem(), opts)
+ } else {
+ dm := dst.AsValueOf(f.ft).Elem()
+ sm := src.AsValueOf(f.ft).Elem()
+ if dm.IsNil() {
+ dm.Set(reflect.New(f.ft.Elem()))
+ }
+ opts.Merge(asMessage(dm), asMessage(sm))
+ }
+}
+
+func mergeMessageSlice(dst, src pointer, f *coderFieldInfo, opts mergeOptions) {
+ for _, sp := range src.PointerSlice() {
+ dm := reflect.New(f.ft.Elem().Elem())
+ if f.mi != nil {
+ f.mi.mergePointer(pointerOfValue(dm), sp, opts)
+ } else {
+ opts.Merge(asMessage(dm), asMessage(sp.AsValueOf(f.ft.Elem().Elem())))
+ }
+ dst.AppendPointerSlice(pointerOfValue(dm))
+ }
+}
+
+func mergeBytes(dst, src pointer, _ *coderFieldInfo, _ mergeOptions) {
+ *dst.Bytes() = append(emptyBuf[:], *src.Bytes()...)
+}
+
+func mergeBytesNoZero(dst, src pointer, _ *coderFieldInfo, _ mergeOptions) {
+ v := *src.Bytes()
+ if len(v) > 0 {
+ *dst.Bytes() = append(emptyBuf[:], v...)
+ }
+}
+
+func mergeBytesSlice(dst, src pointer, _ *coderFieldInfo, _ mergeOptions) {
+ ds := dst.BytesSlice()
+ for _, v := range *src.BytesSlice() {
+ *ds = append(*ds, append(emptyBuf[:], v...))
+ }
+}