From b0ffa22a8a06fb912b5ef36260b2025bf66e1356 Mon Sep 17 00:00:00 2001
From: Adam Scarr <adam@vektah.net>
Date: Tue, 27 Nov 2018 19:27:19 +1100
Subject: [PATCH] Remove strconv.Quote call in hot path to avoid some allocs

go test -benchtime=5s -bench=. -benchmem
goos: linux
goarch: amd64
pkg: github.com/99designs/gqlgen/example/starwars
BenchmarkSimpleQueryNoArgs-8      200000             32125 ns/op            6277 B/op        118 allocs/op
PASS
ok      github.com/99designs/gqlgen/example/starwars    9.768s
---
 graphql/jsonw.go  |  3 +--
 graphql/string.go | 59 +++++++++++++++++++++++++----------------------
 2 files changed, 33 insertions(+), 29 deletions(-)

diff --git a/graphql/jsonw.go b/graphql/jsonw.go
index c112444a7e..c087f63bd0 100644
--- a/graphql/jsonw.go
+++ b/graphql/jsonw.go
@@ -2,7 +2,6 @@ package graphql
 
 import (
 	"io"
-	"strconv"
 )
 
 var nullLit = []byte(`null`)
@@ -56,7 +55,7 @@ func (m *OrderedMap) MarshalGQL(writer io.Writer) {
 		if i != 0 {
 			writer.Write(comma)
 		}
-		io.WriteString(writer, strconv.Quote(key))
+		writeQuotedString(writer, key)
 		writer.Write(colon)
 		m.Values[i].MarshalGQL(writer)
 	}
diff --git a/graphql/string.go b/graphql/string.go
index d5fb32947d..7c1b7d9577 100644
--- a/graphql/string.go
+++ b/graphql/string.go
@@ -10,37 +10,42 @@ const encodeHex = "0123456789ABCDEF"
 
 func MarshalString(s string) Marshaler {
 	return WriterFunc(func(w io.Writer) {
-		start := 0
-		io.WriteString(w, `"`)
-
-		for i, c := range s {
-			if c < 0x20 || c == '\\' || c == '"' {
-				io.WriteString(w, s[start:i])
-
-				switch c {
-				case '\t':
-					io.WriteString(w, `\t`)
-				case '\r':
-					io.WriteString(w, `\r`)
-				case '\n':
-					io.WriteString(w, `\n`)
-				case '\\':
-					io.WriteString(w, `\\`)
-				case '"':
-					io.WriteString(w, `\"`)
-				default:
-					io.WriteString(w, `\u00`)
-					w.Write([]byte{encodeHex[c>>4], encodeHex[c&0xf]})
-				}
-
-				start = i + 1
+		writeQuotedString(w, s)
+	})
+}
+
+func writeQuotedString(w io.Writer, s string) {
+	start := 0
+	io.WriteString(w, `"`)
+
+	for i, c := range s {
+		if c < 0x20 || c == '\\' || c == '"' {
+			io.WriteString(w, s[start:i])
+
+			switch c {
+			case '\t':
+				io.WriteString(w, `\t`)
+			case '\r':
+				io.WriteString(w, `\r`)
+			case '\n':
+				io.WriteString(w, `\n`)
+			case '\\':
+				io.WriteString(w, `\\`)
+			case '"':
+				io.WriteString(w, `\"`)
+			default:
+				io.WriteString(w, `\u00`)
+				w.Write([]byte{encodeHex[c>>4], encodeHex[c&0xf]})
 			}
+
+			start = i + 1
 		}
+	}
 
-		io.WriteString(w, s[start:])
-		io.WriteString(w, `"`)
-	})
+	io.WriteString(w, s[start:])
+	io.WriteString(w, `"`)
 }
+
 func UnmarshalString(v interface{}) (string, error) {
 	switch v := v.(type) {
 	case string: