THRIFT-5767: use string builder to parse strings with escaped quotes

Client: Go

lib/go/test/Makefile.am

@@ -62,7 +62,8 @@ gopath: $(THRIFT) $(THRIFTTEST) \
 				ProcessorMiddlewareTest.thrift \
 				ClientMiddlewareExceptionTest.thrift \
 				ValidateTest.thrift \
-				ForwardType.thrift
+				ForwardType.thrift \
+				StringParseAllocationTest.thrift
 	mkdir -p gopath/src
 	grep -v list.*map.*list.*map $(THRIFTTEST) | grep -v 'set<Insanity>' > ThriftTest.thrift
 	$(THRIFT) $(THRIFTARGS) -r IncludesTest.thrift
@@ -98,6 +99,7 @@ gopath: $(THRIFT) $(THRIFTTEST) \
 	$(THRIFT) $(THRIFTARGS) ClientMiddlewareExceptionTest.thrift
 	$(THRIFT) $(THRIFTARGS) ValidateTest.thrift
 	$(THRIFT) $(THRIFTARGS) ForwardType.thrift
+	$(THRIFT) $(THRIFTARGS) StringParseAllocationTest.thrift
 	ln -nfs ../../tests gopath/src/tests
 	cp -r ./dontexportrwtest gopath/src
 	touch gopath
@@ -169,6 +171,7 @@ EXTRA_DIST = \
 	RefAnnotationFieldsTest.thrift \
 	RequiredFieldTest.thrift \
 	ServicesTest.thrift \
+	StringParseAllocationTest.thrift \
 	TypedefFieldTest.thrift \
 	UnionBinaryTest.thrift \
 	UnionDefaultValueTest.thrift \

lib/go/test/StringParseAllocationTest.thrift

@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+struct StringStruct {
+  1: required string example
+}

lib/go/test/tests/string_parse_allocation_test.go

@@ -0,0 +1,43 @@
+package tests
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/apache/thrift/lib/go/test/gopath/src/stringparseallocationtest"
+	"github.com/apache/thrift/lib/go/thrift"
+)
+
+func TestSimpleJsonStringParse_Allocations(t *testing.T) {
+	byteAllocationLimit := 100 * 1024 // 100 KB
+	res := testing.Benchmark(BenchmarkSimpleJsonStringParse_Allocations)
+	if res.AllocedBytesPerOp() > int64(byteAllocationLimit) {
+		t.Errorf("Total memory allocation size too high: %d (> %d)", res.AllocedBytesPerOp(), byteAllocationLimit)
+	}
+}
+
+func BenchmarkSimpleJsonStringParse_Allocations(b *testing.B) {
+	b.ReportAllocs()
+	b.StopTimer()
+	numEscapedQuotes := 1000
+	var sb strings.Builder
+	for i := 0; i < numEscapedQuotes; i++ {
+		sb.WriteString(`\"`)
+	}
+
+	testString := fmt.Sprintf(`{"1": {"str": "this is a test with %d of escaped quotes %s"}}`, numEscapedQuotes, sb.String())
+	stringStruct := stringparseallocationtest.NewStringStruct()
+	transport := thrift.NewTMemoryBuffer()
+	p := thrift.NewTJSONProtocol(transport)
+
+	for i := 0; i < b.N; i++ {
+		transport.Reset()
+		transport.WriteString(testString)
+		transport.Flush(context.Background())
+		b.StartTimer()
+		_ = stringStruct.Read(context.Background(), p)
+		b.StopTimer()
+	}
+}

lib/go/thrift/simple_json_protocol.go

@@ -30,6 +30,7 @@ import (
 	"io"
 	"math"
 	"strconv"
+	"strings"
 )
 
 type _ParseContext int
@@ -922,15 +923,7 @@ func (p *TSimpleJSONProtocol) ParseStringBody() (string, error) {
 	if err != nil {
 		return "", NewTProtocolException(err)
 	}
-	l := len(line)
-	// count number of escapes to see if we need to keep going
-	i := 1
-	for ; i < l; i++ {
-		if line[l-i-1] != '\\' {
-			break
-		}
-	}
-	if i&0x01 == 1 {
+	if endsWithoutEscapedQuote(line) {
 		v, ok := jsonUnquote(string(JSON_QUOTE) + line)
 		if !ok {
 			return "", NewTProtocolException(err)
@@ -951,27 +944,29 @@ func (p *TSimpleJSONProtocol) ParseStringBody() (string, error) {
 }
 
 func (p *TSimpleJSONProtocol) ParseQuotedStringBody() (string, error) {
-	line, err := p.reader.ReadString(JSON_QUOTE)
-	if err != nil {
-		return "", NewTProtocolException(err)
+	var sb strings.Builder
+
+	for {
+		line, err := p.reader.ReadString(JSON_QUOTE)
+		if err != nil {
+			return "", NewTProtocolException(err)
+		}
+		sb.WriteString(line)
+		if endsWithoutEscapedQuote(line) {
+			return sb.String(), nil
+		}
 	}
-	l := len(line)
-	// count number of escapes to see if we need to keep going
+}
+
+func endsWithoutEscapedQuote(s string) bool {
+	l := len(s)
 	i := 1
 	for ; i < l; i++ {
-		if line[l-i-1] != '\\' {
+		if s[l-i-1] != '\\' {
 			break
 		}
 	}
-	if i&0x01 == 1 {
-		return line, nil
-	}
-	s, err := p.ParseQuotedStringBody()
-	if err != nil {
-		return "", NewTProtocolException(err)
-	}
-	v := line + s
-	return v, nil
+	return i&0x01 == 1
 }
 
 func (p *TSimpleJSONProtocol) ParseBase64EncodedBody() ([]byte, error) {