From 9b0ac1d4c5318b6bf9ed7930320f2bd755f9939c Mon Sep 17 00:00:00 2001 From: Lucas Bremgartner Date: Thu, 5 Sep 2019 23:22:00 +0200 Subject: [PATCH] encoding/json: fix and optimize marshal for quoted string MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since Go 1.2 every string can be marshaled to JSON without error even if it contains invalid UTF-8 byte sequences. Therefore there is no need to use Marshal again for the only reason of enclosing the string in double quotes. Not using Marshal here also removes the error check as there has not been a way for Marshal to fail anyway. name old time/op new time/op delta Issue34127-4 360ns ± 3% 200ns ± 3% -44.56% (p=0.008 n=5+5) name old alloc/op new alloc/op delta Issue34127-4 56.0B ± 0% 40.0B ± 0% -28.57% (p=0.008 n=5+5) name old allocs/op new allocs/op delta Issue34127-4 3.00 ± 0% 2.00 ± 0% -33.33% (p=0.008 n=5+5) Fixes #34154 --- src/encoding/json/bench_test.go | 16 ++++++++++++++++ src/encoding/json/encode.go | 10 +++++----- src/encoding/json/stream_test.go | 10 ++++++++++ 3 files changed, 31 insertions(+), 5 deletions(-) diff --git a/src/encoding/json/bench_test.go b/src/encoding/json/bench_test.go index f2592e3dbdf55..f92d39f0c657a 100644 --- a/src/encoding/json/bench_test.go +++ b/src/encoding/json/bench_test.go @@ -297,6 +297,22 @@ func BenchmarkIssue10335(b *testing.B) { }) } +func BenchmarkIssue34127(b *testing.B) { + b.ReportAllocs() + j := struct { + Bar string `json:"bar,string"` + }{ + Bar: `foobar`, + } + b.RunParallel(func(pb *testing.PB) { + for pb.Next() { + if _, err := Marshal(&j); err != nil { + b.Fatal(err) + } + } + }) +} + func BenchmarkUnmapped(b *testing.B) { b.ReportAllocs() j := []byte(`{"s": "hello", "y": 2, "o": {"x": 0}, "a": [1, 99, {"x": 1}]}`) diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go index f085b5a08d76d..d6821c113556b 100644 --- a/src/encoding/json/encode.go +++ b/src/encoding/json/encode.go @@ -601,11 +601,11 @@ func stringEncoder(e *encodeState, v reflect.Value, opts encOpts) { return } if opts.quoted { - sb, err := Marshal(v.String()) - if err != nil { - e.error(err) - } - e.string(string(sb), opts.escapeHTML) + b := make([]byte, 0, v.Len()+2) + b = append(b, '"') + b = append(b, []byte(v.String())...) + b = append(b, '"') + e.stringBytes(b, opts.escapeHTML) } else { e.string(v.String(), opts.escapeHTML) } diff --git a/src/encoding/json/stream_test.go b/src/encoding/json/stream_test.go index e3317ddeb0b5d..ebb4f231d1518 100644 --- a/src/encoding/json/stream_test.go +++ b/src/encoding/json/stream_test.go @@ -118,6 +118,11 @@ func TestEncoderSetEscapeHTML(t *testing.T) { Ptr strPtrMarshaler }{`""`, `""`} + // https://golang.org/issue/34154 + stringOption := struct { + Bar string `json:"bar,string"` + }{`foobar`} + for _, tt := range []struct { name string v interface{} @@ -137,6 +142,11 @@ func TestEncoderSetEscapeHTML(t *testing.T) { `{"NonPtr":"\u003cstr\u003e","Ptr":"\u003cstr\u003e"}`, `{"NonPtr":"","Ptr":""}`, }, + { + "stringOption", stringOption, + `{"bar":"\"\u003chtml\u003efoobar\u003c/html\u003e\""}`, + `{"bar":"\"foobar\""}`, + }, } { var buf bytes.Buffer enc := NewEncoder(&buf)