expression: add builtin function json_valid (pingcap#12596)

expression/builtin_json.go

@@ -14,12 +14,15 @@
 package expression
 
 import (
+	json2 "encoding/json"
+
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/ast"
 	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/types/json"
 	"github.com/pingcap/tidb/util/chunk"
+	"github.com/pingcap/tidb/util/hack"
 	"github.com/pingcap/tipb/go-tipb"
 )
 
@@ -61,6 +64,9 @@ var (
 	_ builtinFunc = &builtinJSONMergeSig{}
 	_ builtinFunc = &builtinJSONContainsSig{}
 	_ builtinFunc = &builtinJSONLengthSig{}
+	_ builtinFunc = &builtinJSONValidJSONSig{}
+	_ builtinFunc = &builtinJSONValidStringSig{}
+	_ builtinFunc = &builtinJSONValidOthersSig{}
 )
 
 type jsonTypeFunctionClass struct {
@@ -685,7 +691,87 @@ type jsonValidFunctionClass struct {
 }
 
 func (c *jsonValidFunctionClass) getFunction(ctx sessionctx.Context, args []Expression) (builtinFunc, error) {
-	return nil, errFunctionNotExists.GenWithStackByArgs("FUNCTION", "JSON_VALID")
+	if err := c.verifyArgs(args); err != nil {
+		return nil, err
+	}
+
+	var sig builtinFunc
+	argType := args[0].GetType().EvalType()
+	switch argType {
+	case types.ETJson:
+		bf := newBaseBuiltinFuncWithTp(ctx, args, types.ETInt, types.ETJson)
+		sig = &builtinJSONValidJSONSig{bf}
+		sig.setPbCode(tipb.ScalarFuncSig_JsonValidJsonSig)
+	case types.ETString:
+		bf := newBaseBuiltinFuncWithTp(ctx, args, types.ETInt, types.ETString)
+		sig = &builtinJSONValidStringSig{bf}
+		sig.setPbCode(tipb.ScalarFuncSig_JsonValidStringSig)
+	default:
+		bf := newBaseBuiltinFuncWithTp(ctx, args, types.ETInt, argType)
+		sig = &builtinJSONValidOthersSig{bf}
+		sig.setPbCode(tipb.ScalarFuncSig_JsonValidOthersSig)
+	}
+	return sig, nil
+}
+
+type builtinJSONValidJSONSig struct {
+	baseBuiltinFunc
+}
+
+func (b *builtinJSONValidJSONSig) Clone() builtinFunc {
+	newSig := &builtinJSONValidJSONSig{}
+	newSig.cloneFrom(&b.baseBuiltinFunc)
+	return newSig
+}
+
+// evalInt evals a builtinJSONValidJSONSig.
+// See https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-valid
+func (b *builtinJSONValidJSONSig) evalInt(row chunk.Row) (res int64, isNull bool, err error) {
+	_, isNull, err = b.args[0].EvalJSON(b.ctx, row)
+	return 1, isNull, err
+}
+
+type builtinJSONValidStringSig struct {
+	baseBuiltinFunc
+}
+
+func (b *builtinJSONValidStringSig) Clone() builtinFunc {
+	newSig := &builtinJSONValidStringSig{}
+	newSig.cloneFrom(&b.baseBuiltinFunc)
+	return newSig
+}
+
+// evalInt evals a builtinJSONValidStringSig.
+// See https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-valid
+func (b *builtinJSONValidStringSig) evalInt(row chunk.Row) (res int64, isNull bool, err error) {
+	val, isNull, err := b.args[0].EvalString(b.ctx, row)
+	if err != nil || isNull {
+		return 0, isNull, err
+	}
+
+	data := hack.Slice(val)
+	if json2.Valid(data) {
+		res = 1
+	} else {
+		res = 0
+	}
+	return res, false, nil
+}
+
+type builtinJSONValidOthersSig struct {
+	baseBuiltinFunc
+}
+
+func (b *builtinJSONValidOthersSig) Clone() builtinFunc {
+	newSig := &builtinJSONValidOthersSig{}
+	newSig.cloneFrom(&b.baseBuiltinFunc)
+	return newSig
+}
+
+// evalInt evals a builtinJSONValidOthersSig.
+// See https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-valid
+func (b *builtinJSONValidOthersSig) evalInt(row chunk.Row) (res int64, isNull bool, err error) {
+	return 0, false, nil
 }
 
 type jsonArrayAppendFunctionClass struct {

expression/builtin_json_test.go

@@ -495,3 +495,34 @@ func (s *testEvaluatorSuite) TestJSONLength(c *C) {
 		}
 	}
 }
+
+func (s *testEvaluatorSuite) TestJSONValid(c *C) {
+	defer testleak.AfterTest(c)()
+	fc := funcs[ast.JSONValid]
+	tbl := []struct {
+		Input    interface{}
+		Expected interface{}
+	}{
+		{`{"a":1}`, 1},
+		{`hello`, 0},
+		{`"hello"`, 1},
+		{`null`, 1},
+		{`{}`, 1},
+		{`[]`, 1},
+		{`2`, 1},
+		{`2.5`, 1},
+		{`2019-8-19`, 0},
+		{`"2019-8-19"`, 1},
+		{2, 0},
+		{2.5, 0},
+		{nil, nil},
+	}
+	dtbl := tblToDtbl(tbl)
+	for _, t := range dtbl {
+		f, err := fc.getFunction(s.ctx, s.datumsToConstants(t["Input"]))
+		c.Assert(err, IsNil)
+		d, err := evalBuiltinFunc(f, chunk.Row{})
+		c.Assert(err, IsNil)
+		c.Assert(d, testutil.DatumEquals, t["Expected"][0])
+	}
+}

expression/distsql_builtin.go

@@ -438,7 +438,12 @@ func getSignatureByPB(ctx sessionctx.Context, sigCode tipb.ScalarFuncSig, tp *ti
 		f = &builtinLikeSig{base}
 	case tipb.ScalarFuncSig_JsonLengthSig:
 		f = &builtinJSONLengthSig{base}
-
+	case tipb.ScalarFuncSig_JsonValidJsonSig:
+		f = &builtinJSONValidJSONSig{base}
+	case tipb.ScalarFuncSig_JsonValidStringSig:
+		f = &builtinJSONValidStringSig{base}
+	case tipb.ScalarFuncSig_JsonValidOthersSig:
+		f = &builtinJSONValidOthersSig{base}
 	case tipb.ScalarFuncSig_InInt:
 		f = &builtinInIntSig{base}
 	case tipb.ScalarFuncSig_InReal:

expression/integration_test.go

@@ -3292,6 +3292,39 @@ func (s *testIntegrationSuite) TestJSONBuiltin(c *C) {
 	tk.MustExec("CREATE TABLE `my_collection` (	`doc` json DEFAULT NULL, `_id` varchar(32) GENERATED ALWAYS AS (JSON_UNQUOTE(JSON_EXTRACT(doc,'$._id'))) STORED NOT NULL, PRIMARY KEY (`_id`))")
 	_, err := tk.Exec("UPDATE `test`.`my_collection` SET doc=JSON_SET(doc) WHERE (JSON_EXTRACT(doc,'$.name') = 'clare');")
 	c.Assert(err, NotNil)
+
+	r := tk.MustQuery("select json_valid(null);")
+	r.Check(testkit.Rows("<nil>"))
+
+	r = tk.MustQuery(`select json_valid("null");`)
+	r.Check(testkit.Rows("1"))
+
+	r = tk.MustQuery("select json_valid(0);")
+	r.Check(testkit.Rows("0"))
+
+	r = tk.MustQuery(`select json_valid("0");`)
+	r.Check(testkit.Rows("1"))
+
+	r = tk.MustQuery(`select json_valid("hello");`)
+	r.Check(testkit.Rows("0"))
+
+	r = tk.MustQuery(`select json_valid('"hello"');`)
+	r.Check(testkit.Rows("1"))
+
+	r = tk.MustQuery(`select json_valid('{"a":1}');`)
+	r.Check(testkit.Rows("1"))
+
+	r = tk.MustQuery("select json_valid('{}');")
+	r.Check(testkit.Rows("1"))
+
+	r = tk.MustQuery(`select json_valid('[]');`)
+	r.Check(testkit.Rows("1"))
+
+	r = tk.MustQuery("select json_valid('2019-8-19');")
+	r.Check(testkit.Rows("0"))
+
+	r = tk.MustQuery(`select json_valid('"2019-8-19"');`)
+	r.Check(testkit.Rows("1"))
 }
 
 func (s *testIntegrationSuite) TestTimeLiteral(c *C) {

go.mod

@@ -84,3 +84,7 @@ require (
 	gopkg.in/natefinch/lumberjack.v2 v2.0.0
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
 )
+
+go 1.13
+
+replace github.com/pingcap/tipb => github.com/SunRunAway/tipb v0.0.0-20191015062550-6a2d99cc954a

go.sum

@@ -1,5 +1,9 @@
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/SunRunAway/tipb v0.0.0-20191015054648-a49ece5914c0 h1:AdohlGmxzxLVDKHkvbj7z8WpCnqvnRwqCjr5VSAEeCk=
+github.com/SunRunAway/tipb v0.0.0-20191015054648-a49ece5914c0/go.mod h1:myhDmco5Sn/B+RTZYjXbgqmlywhxgM8Gdfy44NfarHw=
+github.com/SunRunAway/tipb v0.0.0-20191015062550-6a2d99cc954a h1:1a1ZaqiYNxpINKwF43UORmt/hbKBe4oYAXMvvITRXtk=
+github.com/SunRunAway/tipb v0.0.0-20191015062550-6a2d99cc954a/go.mod h1:myhDmco5Sn/B+RTZYjXbgqmlywhxgM8Gdfy44NfarHw=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/apache/thrift v0.0.0-20161221203622-b2a4d4ae21c7 h1:Fv9bK1Q+ly/ROk4aJsVMeuIwPel4bEnD8EPiI91nZMg=
 github.com/apache/thrift v0.0.0-20161221203622-b2a4d4ae21c7/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=