proto, internal/impl: avoid string->[]byte conversions
We trust the compiler to optimize away the string->[]byte conversion in
code like:
b = wire.AppendBytes(b, []byte(s))
In testing (go 1.12.5 linux/amd64), this optimization is not happening.
Perhaps newer versions of the compiler will optimize this, but we
shouldn't rely on it; avoid unnecessary conversions.
Benchmark differences vs https://golang.org/cl/171462:
name old time/op new time/op delta
Wire/Marshal/google_message1_proto2-6 310ns ± 2% 189ns ± 3% -39.20% (p=0.000 n=8+8)
Wire/Marshal/google_message1_proto3-6 389ns ± 8% 261ns ± 2% -33.03% (p=0.000 n=8+8)
Wire/Marshal/google_message2-6 103µs ±11% 59µs ± 4% -42.17% (p=0.000 n=8+8)
name old alloc/op new alloc/op delta
Wire/Marshal/google_message1_proto2-6 592B ± 0% 240B ± 0% -59.46% (p=0.000 n=8+8)
Wire/Marshal/google_message1_proto3-6 576B ± 0% 224B ± 0% -61.11% (p=0.000 n=8+8)
Wire/Marshal/google_message2-6 196kB ± 0% 90kB ± 0% -54.05% (p=0.000 n=8+8)
name old allocs/op new allocs/op delta
Wire/Marshal/google_message1_proto2-6 5.00 ± 0% 1.00 ± 0% -80.00% (p=0.000 n=8+8)
Wire/Marshal/google_message1_proto3-6 5.00 ± 0% 1.00 ± 0% -80.00% (p=0.000 n=8+8)
Wire/Marshal/google_message2-6 1.66k ± 0% 0.00k ± 0% -99.94% (p=0.000 n=8+8)
Change-Id: Idab7634b8c86604dffa46895ba2e61be38c9bd9c
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/183380
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
diff --git a/internal/impl/encode_field.go b/internal/impl/encode_field.go
index f4c9406..b8afb99 100644
--- a/internal/impl/encode_field.go
+++ b/internal/impl/encode_field.go
@@ -412,7 +412,7 @@
func appendStringValidateUTF8(b []byte, p pointer, wiretag uint64, _ marshalOptions) ([]byte, error) {
v := *p.String()
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
if !utf8.ValidString(v) {
return b, errInvalidUTF8{}
}
@@ -430,7 +430,7 @@
return b, nil
}
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
if !utf8.ValidString(v) {
return b, errInvalidUTF8{}
}
@@ -445,7 +445,7 @@
func sizeStringSliceValidateUTF8(p pointer, tagsize int, _ marshalOptions) (size int) {
s := *p.StringSlice()
for _, v := range s {
- size += tagsize + wire.SizeBytes(len([]byte(v)))
+ size += tagsize + wire.SizeBytes(len(v))
}
return size
}
@@ -455,7 +455,7 @@
var err error
for _, v := range s {
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
if !utf8.ValidString(v) {
err = errInvalidUTF8{}
}
@@ -470,13 +470,13 @@
func sizeStringIfaceValidateUTF8(ival interface{}, tagsize int, _ marshalOptions) int {
v := ival.(string)
- return tagsize + wire.SizeBytes(len([]byte(v)))
+ return tagsize + wire.SizeBytes(len(v))
}
func appendStringIfaceValidateUTF8(b []byte, ival interface{}, wiretag uint64, _ marshalOptions) ([]byte, error) {
v := ival.(string)
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
if !utf8.ValidString(v) {
return b, errInvalidUTF8{}
}