stmt: add json.RawMessage for converter and prepared statement

Following #1058, in order for the driver.Value to get as a json.RawMessage,
the converter should accept it as a valid value, and handle it as bytes in
case where interpolation is disabled

Author: a8m

AUTHORS

@@ -17,6 +17,7 @@ Alex Snast <alexsn at fb.com>
 Alexey Palazhchenko <alexey.palazhchenko at gmail.com>
 Andrew Reid <andrew.reid at tixtrack.com>
 Arne Hormann <arnehormann at gmail.com>
+Ariel Mashraki <ariel at mashraki.co.il>
 Asta Xie <xiemengjun at gmail.com>
 Bulat Gaifullin <gaifullinbf at gmail.com>
 Carlos Nieto <jose.carlos at menteslibres.net>

packets.go

@@ -13,6 +13,7 @@ import (
 	"crypto/tls"
 	"database/sql/driver"
 	"encoding/binary"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -1063,19 +1064,26 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 					paramValues = append(paramValues, 0x00)
 				}
 
-			case []byte:
+			case []byte, json.RawMessage:
+				var (
+					ok bool
+					b  []byte
+				)
+				if b, ok = v.(json.RawMessage); !ok {
+					b = v.([]byte)
+				}
 				// Common case (non-nil value) first
-				if v != nil {
+				if b != nil {
 					paramTypes[i+i] = byte(fieldTypeString)
 					paramTypes[i+i+1] = 0x00
 
-					if len(v) < longDataSize {
+					if len(b) < longDataSize {
 						paramValues = appendLengthEncodedInteger(paramValues,
-							uint64(len(v)),
+							uint64(len(b)),
 						)
-						paramValues = append(paramValues, v...)
+						paramValues = append(paramValues, b...)
 					} else {
-						if err := stmt.writeCommandLongData(i, v); err != nil {
+						if err := stmt.writeCommandLongData(i, b); err != nil {
 							return err
 						}
 					}

statement.go

@@ -10,6 +10,7 @@ package mysql
 
 import (
 	"database/sql/driver"
+	"encoding/json"
 	"fmt"
 	"io"
 	"reflect"
@@ -129,6 +130,8 @@ func (stmt *mysqlStmt) query(args []driver.Value) (*binaryRows, error) {
 	return rows, err
 }
 
+var jsonType = reflect.TypeOf(json.RawMessage{})
+
 type converter struct{}
 
 // ConvertValue mirrors the reference/default converter in database/sql/driver
@@ -151,7 +154,6 @@ func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
 		}
 		return sv, nil
 	}
-
 	rv := reflect.ValueOf(v)
 	switch rv.Kind() {
 	case reflect.Ptr:
@@ -170,11 +172,14 @@ func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
 	case reflect.Bool:
 		return rv.Bool(), nil
 	case reflect.Slice:
-		ek := rv.Type().Elem().Kind()
-		if ek == reflect.Uint8 {
+		switch t := rv.Type(); {
+		case t == jsonType:
+			return v, nil
+		case t.Elem().Kind() == reflect.Uint8:
 			return rv.Bytes(), nil
+		default:
+			return nil, fmt.Errorf("unsupported type %T, a slice of %s", v, t.Elem().Kind())
 		}
-		return nil, fmt.Errorf("unsupported type %T, a slice of %s", v, ek)
 	case reflect.String:
 		return rv.String(), nil
 	}

statement_test.go

@@ -10,6 +10,7 @@ package mysql
 
 import (
 	"bytes"
+	"encoding/json"
 	"testing"
 )
 
@@ -124,3 +125,17 @@ func TestConvertUnsignedIntegers(t *testing.T) {
 		t.Fatalf("uint64 high-bit converted, got %#v %T", output, output)
 	}
 }
+
+func TestConvertJSON(t *testing.T) {
+	raw := json.RawMessage("{}")
+
+	out, err := converter{}.ConvertValue(&raw)
+
+	if err != nil {
+		t.Fatal("json.RawMessage was failed in convert", err)
+	}
+
+	if _, ok := out.(json.RawMessage); !ok {
+		t.Fatalf("json.RawMessage converted, got %#v %T", out, out)
+	}
+}