Add new -disable_members_unescape option to avoid unescaping of member names, ints, ...

Improves performance for about 15% on BenchmarkEJ_Unmarshal_M-8

Makefile

@@ -28,7 +28,7 @@ generate: build
 	bin/easyjson -all ./tests/html.go
 	bin/easyjson -snake_case ./tests/snake.go
 	bin/easyjson -omit_empty ./tests/omitempty.go
-	bin/easyjson -build_tags=use_easyjson ./benchmark/data.go
+	bin/easyjson -build_tags=use_easyjson -disable_members_unescape ./benchmark/data.go
 	bin/easyjson ./tests/nested_easy.go
 	bin/easyjson ./tests/named_type.go
 	bin/easyjson ./tests/custom_map_key_type.go

bootstrap/bootstrap.go

@@ -23,18 +23,19 @@ type Generator struct {
 	PkgPath, PkgName string
 	Types            []string
 
-	NoStdMarshalers       bool
-	SnakeCase             bool
-	LowerCamelCase        bool
-	OmitEmpty             bool
-	DisallowUnknownFields bool
+	NoStdMarshalers          bool
+	SnakeCase                bool
+	LowerCamelCase           bool
+	OmitEmpty                bool
+	DisallowUnknownFields    bool
+	SkipMemberNameUnescaping bool
 
 	OutName   string
 	BuildTags string
 
-	StubsOnly  bool
-	LeaveTemps bool
-	NoFormat   bool
+	StubsOnly   bool
+	LeaveTemps  bool
+	NoFormat    bool
 	SimpleBytes bool
 }
 
@@ -129,6 +130,9 @@ func (g *Generator) writeMain() (path string, err error) {
 	if g.SimpleBytes {
 		fmt.Fprintln(f, "  g.SimpleBytes()")
 	}
+	if g.SkipMemberNameUnescaping {
+		fmt.Fprintln(f, "  g.SkipMemberNameUnescaping()")
+	}
 
 	sort.Strings(g.Types)
 	for _, v := range g.Types {

easyjson/main.go

@@ -29,6 +29,7 @@ var noformat = flag.Bool("noformat", false, "do not run 'gofmt -w' on output fil
 var specifiedName = flag.String("output_filename", "", "specify the filename of the output")
 var processPkg = flag.Bool("pkg", false, "process the whole package instead of just the given file")
 var disallowUnknownFields = flag.Bool("disallow_unknown_fields", false, "return error if any unknown field in json appeared")
+var skipMemberNameUnescaping = flag.Bool("disable_members_unescape", false, "don't perform unescaping of member names to improve performance")
 
 func generate(fname string) (err error) {
 	fInfo, err := os.Stat(fname)
@@ -62,20 +63,21 @@ func generate(fname string) (err error) {
 	}
 
 	g := bootstrap.Generator{
-		BuildTags:             trimmedBuildTags,
-		PkgPath:               p.PkgPath,
-		PkgName:               p.PkgName,
-		Types:                 p.StructNames,
-		SnakeCase:             *snakeCase,
-		LowerCamelCase:        *lowerCamelCase,
-		NoStdMarshalers:       *noStdMarshalers,
-		DisallowUnknownFields: *disallowUnknownFields,
-		OmitEmpty:             *omitEmpty,
-		LeaveTemps:            *leaveTemps,
-		OutName:               outName,
-		StubsOnly:             *stubs,
-		NoFormat:              *noformat,
-		SimpleBytes:           *simpleBytes,
+		BuildTags:                trimmedBuildTags,
+		PkgPath:                  p.PkgPath,
+		PkgName:                  p.PkgName,
+		Types:                    p.StructNames,
+		SnakeCase:                *snakeCase,
+		LowerCamelCase:           *lowerCamelCase,
+		NoStdMarshalers:          *noStdMarshalers,
+		DisallowUnknownFields:    *disallowUnknownFields,
+		SkipMemberNameUnescaping: *skipMemberNameUnescaping,
+		OmitEmpty:                *omitEmpty,
+		LeaveTemps:               *leaveTemps,
+		OutName:                  outName,
+		StubsOnly:                *stubs,
+		NoFormat:                 *noformat,
+		SimpleBytes:              *simpleBytes,
 	}
 
 	if err := g.Run(); err != nil {

gen/decoder.go

@@ -457,6 +457,9 @@ func (g *Generator) genStructDecoder(t reflect.Type) error {
 	typ := g.getType(t)
 
 	fmt.Fprintln(g.out, "func "+fname+"(in *jlexer.Lexer, out *"+typ+") {")
+	if g.skipMemberNameUnescaping {
+		fmt.Fprintln(g.out, "  in.SkipUnescape = true")
+	}
 	fmt.Fprintln(g.out, "  isTopLevel := in.IsStart()")
 	fmt.Fprintln(g.out, "  if in.IsNull() {")
 	fmt.Fprintln(g.out, "    if isTopLevel {")

gen/generator.go

@@ -33,11 +33,12 @@ type Generator struct {
 
 	varCounter int
 
-	noStdMarshalers       bool
-	omitEmpty             bool
-	disallowUnknownFields bool
-	fieldNamer            FieldNamer
-	simpleBytes           bool
+	noStdMarshalers          bool
+	omitEmpty                bool
+	disallowUnknownFields    bool
+	fieldNamer               FieldNamer
+	simpleBytes              bool
+	skipMemberNameUnescaping bool
 
 	// package path to local alias map for tracking imports
 	imports map[string]string
@@ -117,6 +118,11 @@ func (g *Generator) DisallowUnknownFields() {
 	g.disallowUnknownFields = true
 }
 
+// SkipMemberNameUnescaping instructs to skip member names unescaping to improve performance
+func (g *Generator) SkipMemberNameUnescaping() {
+	g.skipMemberNameUnescaping = true
+}
+
 // OmitEmpty triggers `json=",omitempty"` behaviour by default.
 func (g *Generator) OmitEmpty() {
 	g.omitEmpty = true

jlexer/lexer.go

@@ -49,6 +49,7 @@ type Lexer struct {
 
 	firstElement bool // Whether current element is the first in array or an object.
 	wantSep      byte // A comma or a colon character, which need to occur before a token.
+	SkipUnescape bool // Skip unescaping on all but user returned strings (i.e. member names, numbers, bytes etc.)
 
 	UseMultipleErrors bool          // If we want to use multiple errors.
 	fatalError        error         // Fatal error occurred during lexing. It is usually a syntax error.
@@ -606,9 +607,11 @@ func (r *Lexer) unsafeString() (string, []byte) {
 		r.errInvalidToken("string")
 		return "", nil
 	}
-	if err := r.unescapeStringToken(); err != nil {
-		r.errInvalidToken("string")
-		return "", nil
+	if !r.SkipUnescape {
+		if err := r.unescapeStringToken(); err != nil {
+			r.errInvalidToken("string")
+			return "", nil
+		}
 	}
 
 	bytes := r.token.byteValue