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_gen.go b/internal/impl/encode_gen.go
index 6f55323..7dbb0bc 100644
--- a/internal/impl/encode_gen.go
+++ b/internal/impl/encode_gen.go
@@ -2154,14 +2154,14 @@
// sizeString returns the size of wire encoding a string pointer as a String.
func sizeString(p pointer, tagsize int, _ marshalOptions) (size int) {
v := *p.String()
- return tagsize + wire.SizeBytes(len([]byte(v)))
+ return tagsize + wire.SizeBytes(len(v))
}
// appendString wire encodes a string pointer as a String.
func appendString(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)
return b, nil
}
@@ -2177,7 +2177,7 @@
if len(v) == 0 {
return 0
}
- return tagsize + wire.SizeBytes(len([]byte(v)))
+ return tagsize + wire.SizeBytes(len(v))
}
// appendString wire encodes a string pointer as a String.
@@ -2188,7 +2188,7 @@
return b, nil
}
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
return b, nil
}
@@ -2201,7 +2201,7 @@
// It panics if the pointer is nil.
func sizeStringPtr(p pointer, tagsize int, _ marshalOptions) (size int) {
v := **p.StringPtr()
- return tagsize + wire.SizeBytes(len([]byte(v)))
+ return tagsize + wire.SizeBytes(len(v))
}
// appendString wire encodes a *string pointer as a String.
@@ -2209,7 +2209,7 @@
func appendStringPtr(b []byte, p pointer, wiretag uint64, _ marshalOptions) ([]byte, error) {
v := **p.StringPtr()
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
return b, nil
}
@@ -2222,7 +2222,7 @@
func sizeStringSlice(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
}
@@ -2232,7 +2232,7 @@
s := *p.StringSlice()
for _, v := range s {
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
}
return b, nil
}
@@ -2245,14 +2245,14 @@
// sizeStringIface returns the size of wire encoding a string value as a String.
func sizeStringIface(ival interface{}, tagsize int, _ marshalOptions) int {
v := ival.(string)
- return tagsize + wire.SizeBytes(len([]byte(v)))
+ return tagsize + wire.SizeBytes(len(v))
}
// appendStringIface encodes a string value as a String.
func appendStringIface(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)
return b, nil
}
@@ -2265,7 +2265,7 @@
func sizeStringSliceIface(ival interface{}, tagsize int, _ marshalOptions) (size int) {
s := *ival.(*[]string)
for _, v := range s {
- size += tagsize + wire.SizeBytes(len([]byte(v)))
+ size += tagsize + wire.SizeBytes(len(v))
}
return size
}
@@ -2275,7 +2275,7 @@
s := *ival.(*[]string)
for _, v := range s {
b = wire.AppendVarint(b, wiretag)
- b = wire.AppendBytes(b, []byte(v))
+ b = wire.AppendString(b, v)
}
return b, nil
}