builtin: add sha/sha1 built-in function (pingcap#2781)

* mod: add sha/sha1 built-in function

* Address comment

* unify  return style

* address comments, add some test cases

expression/builtin_encryption.go

@@ -15,6 +15,7 @@ package expression
 
 import (
 	"crypto/md5"
+	"crypto/sha1"
 	"fmt"
 
 	"github.com/juju/errors"
@@ -105,12 +106,12 @@ type builtinAesDecryptSig struct {
 func (b *builtinAesDecryptSig) eval(row []types.Datum) (d types.Datum, err error) {
 	args, err := b.evalArgs(row)
 	if err != nil {
-		return types.Datum{}, errors.Trace(err)
+		return d, errors.Trace(err)
 	}
 	for _, arg := range args {
 		// If either function argument is NULL, the function returns NULL.
 		if arg.IsNull() {
-			return
+			return d, nil
 		}
 	}
 	cryptStr := args[0].GetBytes()
@@ -123,7 +124,7 @@ func (b *builtinAesDecryptSig) eval(row []types.Datum) (d types.Datum, err error
 		return d, errors.Trace(err)
 	}
 	d.SetString(string(data))
-	return
+	return d, nil
 }
 
 type aesEncryptFunctionClass struct {
@@ -533,8 +534,26 @@ type builtinSHA1Sig struct {
 }
 
 // See https://dev.mysql.com/doc/refman/5.7/en/encryption-functions.html#function_sha1
+// The value is returned as a string of 40 hexadecimal digits, or NULL if the argument was NULL.
 func (b *builtinSHA1Sig) eval(row []types.Datum) (d types.Datum, err error) {
-	return d, errFunctionNotExists.GenByArgs("SHA1")
+	args, err := b.evalArgs(row)
+	if err != nil {
+		return types.Datum{}, errors.Trace(err)
+	}
+	// SHA/SHA1 function only accept 1 parameter
+	arg := args[0]
+	if arg.IsNull() {
+		return d, nil
+	}
+	bin, err := arg.ToBytes()
+	if err != nil {
+		return d, errors.Trace(err)
+	}
+	hasher := sha1.New()
+	hasher.Write(bin)
+	data := fmt.Sprintf("%x", hasher.Sum(nil))
+	d.SetString(data)
+	return d, nil
 }
 
 type sha2FunctionClass struct {

expression/builtin_encryption_test.go

@@ -51,6 +51,38 @@ var md5Cases = []md5Test{
 	{nil, nil},
 }
 
+var shaCases = []struct {
+	origin interface{}
+	crypt  string
+}{
+	{"test", "a94a8fe5ccb19ba61c4c0873d391e987982fbbd3"},
+	{"c4pt0r", "034923dcabf099fc4c8917c0ab91ffcd4c2578a6"},
+	{"pingcap", "73bf9ef43a44f42e2ea2894d62f0917af149a006"},
+	{"foobar", "8843d7f92416211de9ebb963ff4ce28125932878"},
+	{1024, "128351137a9c47206c4507dcf2e6fbeeca3a9079"},
+	{123.45, "22f8b438ad7e89300b51d88684f3f0b9fa1d7a32"},
+}
+
+func (s *testEvaluatorSuite) TestShaEncrypt(c *C) {
+	defer testleak.AfterTest(c)()
+	fc := funcs[ast.SHA]
+	for _, test := range shaCases {
+		in := types.NewDatum(test.origin)
+		f, _ := fc.getFunction(datumsToConstants([]types.Datum{in}), s.ctx)
+		crypt, err := f.eval(nil)
+		c.Assert(err, IsNil)
+		res, err := crypt.ToString()
+		c.Assert(err, IsNil)
+		c.Assert(res, Equals, test.crypt)
+	}
+	// test NULL input for sha
+	var argNull types.Datum
+	f, _ := fc.getFunction(datumsToConstants([]types.Datum{argNull}), s.ctx)
+	crypt, err := f.eval(nil)
+	c.Assert(err, IsNil)
+	c.Assert(crypt.IsNull(), IsTrue)
+}
+
 func (s *testEvaluatorSuite) TestAESEncrypt(c *C) {
 	defer testleak.AfterTest(c)()
 	fc := funcs[ast.AesEncrypt]

plan/typeinferer.go

@@ -400,6 +400,10 @@ func (v *typeInferrer) handleFuncCallExpr(x *ast.FuncCallExpr) {
 		tp = types.NewFieldType(mysql.TypeVarString)
 		chs = v.defaultCharset
 		tp.Flen = 32
+	case ast.SHA, ast.SHA1:
+		tp = types.NewFieldType(mysql.TypeVarString)
+		chs = v.defaultCharset
+		tp.Flen = 40
 	default:
 		tp = types.NewFieldType(mysql.TypeUnspecified)
 	}

plan/typeinferer_test.go

@@ -235,6 +235,8 @@ func (ts *testTypeInferrerSuite) TestInferType(c *C) {
 		{`aes_encrypt("pingcap", "fit2cloud@2014")`, mysql.TypeVarString, "utf8"},
 		{`aes_decrypt("pingcap", "fit2cloud@2014")`, mysql.TypeVarString, "utf8"},
 		{`md5(123)`, mysql.TypeVarString, "utf8"},
+		{`sha1(123)`, mysql.TypeVarString, "utf8"},
+		{`sha(123)`, mysql.TypeVarString, "utf8"},
 	}
 	for _, ca := range cases {
 		ctx := testKit.Se.(context.Context)