executor: fix The JSON Data can not import to TiDB correctly by `load…

… data` (#21043) (#21074)

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

executor/executor_pkg_test.go

@@ -235,6 +235,7 @@ func (s *testExecSuite) TestGetFieldsFromLine(c *C) {
 		FieldsInfo: &ast.FieldsClause{
 			Enclosed:   '"',
 			Terminated: ",",
+			Escaped:    '\\',
 		},
 	}
 
@@ -248,6 +249,33 @@ func (s *testExecSuite) TestGetFieldsFromLine(c *C) {
 	c.Assert(err, IsNil)
 }
 
+func (s *testExecSerialSuite) TestLoadDataWithDifferentEscapeChar(c *C) {
+	tests := []struct {
+		input      string
+		escapeChar byte
+		expected   []string
+	}{
+		{
+			`"{""itemRangeType"":0,""itemContainType"":0,""shopRangeType"":1,""shopJson"":""[{\""id\"":\""A1234\"",\""shopName\"":\""AAAAAA\""}]""}"`,
+			byte(0), // escaped by ''
+			[]string{`{"itemRangeType":0,"itemContainType":0,"shopRangeType":1,"shopJson":"[{\"id\":\"A1234\",\"shopName\":\"AAAAAA\"}]"}`},
+		},
+	}
+
+	for _, test := range tests {
+		ldInfo := LoadDataInfo{
+			FieldsInfo: &ast.FieldsClause{
+				Enclosed:   '"',
+				Terminated: ",",
+				Escaped:    test.escapeChar,
+			},
+		}
+		got, err := ldInfo.getFieldsFromLine([]byte(test.input))
+		c.Assert(err, IsNil, Commentf("failed: %s", test.input))
+		assertEqualStrings(c, got, test.expected)
+	}
+}
+
 func assertEqualStrings(c *C, got []field, expect []string) {
 	c.Assert(len(got), Equals, len(expect))
 	for i := 0; i < len(got); i++ {

executor/load_data.go

@@ -510,17 +510,19 @@ type fieldWriter struct {
 	term          string
 	enclosedChar  byte
 	fieldTermChar byte
+	escapeChar    byte
 	isEnclosed    bool
 	isLineStart   bool
 	isFieldStart  bool
 }
 
-func (w *fieldWriter) Init(enclosedChar byte, fieldTermChar byte, readBuf []byte, term string) {
+func (w *fieldWriter) Init(enclosedChar, escapeChar, fieldTermChar byte, readBuf []byte, term string) {
 	w.isEnclosed = false
 	w.isLineStart = true
 	w.isFieldStart = true
 	w.ReadBuf = readBuf
 	w.enclosedChar = enclosedChar
+	w.escapeChar = escapeChar
 	w.fieldTermChar = fieldTermChar
 	w.term = term
 }
@@ -626,13 +628,12 @@ func (w *fieldWriter) GetField() (bool, field) {
 				w.OutputBuf = append(w.OutputBuf, w.enclosedChar)
 				w.putback()
 			}
-		} else if ch == '\\' {
-			// TODO: escape only support '\'
+		} else if ch == w.escapeChar {
 			// When the escaped character is interpreted as if
 			// it was not escaped, backslash is ignored.
 			flag, ch = w.getChar()
 			if flag {
-				w.OutputBuf = append(w.OutputBuf, '\\')
+				w.OutputBuf = append(w.OutputBuf, w.escapeChar)
 				w.OutputBuf = append(w.OutputBuf, ch)
 			}
 		} else {
@@ -654,10 +655,10 @@ func (e *LoadDataInfo) getFieldsFromLine(line []byte) ([]field, error) {
 		return fields, nil
 	}
 
-	reader.Init(e.FieldsInfo.Enclosed, e.FieldsInfo.Terminated[0], line, e.FieldsInfo.Terminated)
+	reader.Init(e.FieldsInfo.Enclosed, e.FieldsInfo.Escaped, e.FieldsInfo.Terminated[0], line, e.FieldsInfo.Terminated)
 	for {
 		eol, f := reader.GetField()
-		f = f.escape()
+		f = f.escape(reader.escapeChar)
 		if bytes.Equal(f.str, null) && !f.enclosed {
 			f.str = []byte{'N'}
 			f.maybeNull = true
@@ -672,12 +673,11 @@ func (e *LoadDataInfo) getFieldsFromLine(line []byte) ([]field, error) {
 
 // escape handles escape characters when running load data statement.
 // See http://dev.mysql.com/doc/refman/5.7/en/load-data.html
-// TODO: escape only support '\' as the `ESCAPED BY` character, it should support specify characters.
-func (f *field) escape() field {
+func (f *field) escape(escapeChar byte) field {
 	pos := 0
 	for i := 0; i < len(f.str); i++ {
 		c := f.str[i]
-		if i+1 < len(f.str) && f.str[i] == '\\' {
+		if i+1 < len(f.str) && f.str[i] == escapeChar {
 			c = f.escapeChar(f.str[i+1])
 			i++
 		}