From 75a6ad40b99c1d8ba695920b1dfcc7b40daa4340 Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Thu, 12 Aug 2021 13:51:24 +0900
Subject: [PATCH] Fix decoding of binary type with escaped char

---
 decode_test.go            |  33 ++++++++++
 internal/decoder/bytes.go | 125 ++++++++++----------------------------
 2 files changed, 64 insertions(+), 94 deletions(-)

diff --git a/decode_test.go b/decode_test.go
index a0d4eda..8319b0f 100644
--- a/decode_test.go
+++ b/decode_test.go
@@ -3699,3 +3699,36 @@ func TestIssue251(t *testing.T) {
 	}
 	t.Log(array)
 }
+
+func TestDecodeBinaryTypeWithEscapedChar(t *testing.T) {
+	type T struct {
+		Msg []byte `json:"msg"`
+	}
+	content := []byte(`{"msg":"aGVsbG8K\n"}`)
+	t.Run("unmarshal", func(t *testing.T) {
+		var expected T
+		if err := stdjson.Unmarshal(content, &expected); err != nil {
+			t.Fatal(err)
+		}
+		var got T
+		if err := json.Unmarshal(content, &got); err != nil {
+			t.Fatal(err)
+		}
+		if !bytes.Equal(expected.Msg, got.Msg) {
+			t.Fatalf("failed to decode binary type with escaped char. expected %q but got %q", expected.Msg, got.Msg)
+		}
+	})
+	t.Run("stream", func(t *testing.T) {
+		var expected T
+		if err := stdjson.NewDecoder(bytes.NewBuffer(content)).Decode(&expected); err != nil {
+			t.Fatal(err)
+		}
+		var got T
+		if err := json.NewDecoder(bytes.NewBuffer(content)).Decode(&got); err != nil {
+			t.Fatal(err)
+		}
+		if !bytes.Equal(expected.Msg, got.Msg) {
+			t.Fatalf("failed to decode binary type with escaped char. expected %q but got %q", expected.Msg, got.Msg)
+		}
+	})
+}
diff --git a/internal/decoder/bytes.go b/internal/decoder/bytes.go
index 0c4681a..01a37fe 100644
--- a/internal/decoder/bytes.go
+++ b/internal/decoder/bytes.go
@@ -9,10 +9,11 @@ import (
 )
 
 type bytesDecoder struct {
-	typ          *runtime.Type
-	sliceDecoder Decoder
-	structName   string
-	fieldName    string
+	typ           *runtime.Type
+	sliceDecoder  Decoder
+	stringDecoder *stringDecoder
+	structName    string
+	fieldName     string
 }
 
 func byteUnmarshalerSliceDecoder(typ *runtime.Type, structName string, fieldName string) Decoder {
@@ -31,10 +32,11 @@ func byteUnmarshalerSliceDecoder(typ *runtime.Type, structName string, fieldName
 
 func newBytesDecoder(typ *runtime.Type, structName string, fieldName string) *bytesDecoder {
 	return &bytesDecoder{
-		typ:          typ,
-		sliceDecoder: byteUnmarshalerSliceDecoder(typ, structName, fieldName),
-		structName:   structName,
-		fieldName:    fieldName,
+		typ:           typ,
+		sliceDecoder:  byteUnmarshalerSliceDecoder(typ, structName, fieldName),
+		stringDecoder: newStringDecoder(structName, fieldName),
+		structName:    structName,
+		fieldName:     fieldName,
 	}
 }
 
@@ -77,101 +79,36 @@ func (d *bytesDecoder) Decode(ctx *RuntimeContext, cursor, depth int64, p unsafe
 	return cursor, nil
 }
 
-func binaryBytes(s *Stream) ([]byte, error) {
-	s.cursor++
-	start := s.cursor
-	for {
-		switch s.char() {
-		case '"':
-			literal := s.buf[start:s.cursor]
-			s.cursor++
-			return literal, nil
-		case nul:
-			if s.read() {
-				continue
-			}
-			goto ERROR
-		}
-		s.cursor++
-	}
-ERROR:
-	return nil, errors.ErrUnexpectedEndOfJSON("[]byte", s.totalOffset())
-}
-
 func (d *bytesDecoder) decodeStreamBinary(s *Stream, depth int64, p unsafe.Pointer) ([]byte, error) {
-	for {
-		switch s.char() {
-		case ' ', '\n', '\t', '\r':
-			s.cursor++
-			continue
-		case '"':
-			return binaryBytes(s)
-		case 'n':
-			if err := nullBytes(s); err != nil {
-				return nil, err
-			}
-			return nil, nil
-		case '[':
-			if d.sliceDecoder == nil {
-				return nil, &errors.UnmarshalTypeError{
-					Type:   runtime.RType2Type(d.typ),
-					Offset: s.totalOffset(),
-				}
-			}
-			if err := d.sliceDecoder.DecodeStream(s, depth, p); err != nil {
-				return nil, err
-			}
-			return nil, nil
-		case nul:
-			if s.read() {
-				continue
+	c := s.skipWhiteSpace()
+	if c == '[' {
+		if d.sliceDecoder == nil {
+			return nil, &errors.UnmarshalTypeError{
+				Type:   runtime.RType2Type(d.typ),
+				Offset: s.totalOffset(),
 			}
 		}
-		break
+		err := d.sliceDecoder.DecodeStream(s, depth, p)
+		return nil, err
 	}
-	return nil, errors.ErrNotAtBeginningOfValue(s.totalOffset())
+	return d.stringDecoder.decodeStreamByte(s)
 }
 
 func (d *bytesDecoder) decodeBinary(ctx *RuntimeContext, cursor, depth int64, p unsafe.Pointer) ([]byte, int64, error) {
 	buf := ctx.Buf
-	for {
-		switch buf[cursor] {
-		case ' ', '\n', '\t', '\r':
-			cursor++
-		case '"':
-			cursor++
-			start := cursor
-			for {
-				switch buf[cursor] {
-				case '"':
-					literal := buf[start:cursor]
-					cursor++
-					return literal, cursor, nil
-				case nul:
-					return nil, 0, errors.ErrUnexpectedEndOfJSON("[]byte", cursor)
-				}
-				cursor++
+	cursor = skipWhiteSpace(buf, cursor)
+	if buf[cursor] == '[' {
+		if d.sliceDecoder == nil {
+			return nil, 0, &errors.UnmarshalTypeError{
+				Type:   runtime.RType2Type(d.typ),
+				Offset: cursor,
 			}
-		case '[':
-			if d.sliceDecoder == nil {
-				return nil, 0, &errors.UnmarshalTypeError{
-					Type:   runtime.RType2Type(d.typ),
-					Offset: cursor,
-				}
-			}
-			c, err := d.sliceDecoder.Decode(ctx, cursor, depth, p)
-			if err != nil {
-				return nil, 0, err
-			}
-			return nil, c, nil
-		case 'n':
-			if err := validateNull(buf, cursor); err != nil {
-				return nil, 0, err
-			}
-			cursor += 4
-			return nil, cursor, nil
-		default:
-			return nil, 0, errors.ErrNotAtBeginningOfValue(cursor)
 		}
+		c, err := d.sliceDecoder.Decode(ctx, cursor, depth, p)
+		if err != nil {
+			return nil, 0, err
+		}
+		return nil, c, nil
 	}
+	return d.stringDecoder.decodeByte(buf, cursor)
 }