utils: Fix possible misuse of reflect.SliceHeader vet error when go 1.16.6 #139

utils/unsafe.go

@@ -22,15 +22,18 @@ import (
 )
 
 // BytesToString casts slice to string without copy
-func BytesToString(b []byte) (s string) {
+func BytesToString(b []byte) string {
 	if len(b) == 0 {
 		return ""
 	}
 
-	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
-	sh := reflect.StringHeader{Data: bh.Data, Len: bh.Len}
-
-	return *(*string)(unsafe.Pointer(&sh))
+	p := unsafe.Pointer((*reflect.StringHeader)(unsafe.Pointer(&b)).Data)
+	var s string
+	sh := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+	sh.Data = uintptr(p)
+	sh.Cap = len(b)
+	sh.Len = len(b)
+	return s
 }
 
 // StringToBytes casts string to slice without copy
@@ -39,8 +42,11 @@ func StringToBytes(s string) []byte {
 		return []byte{}
 	}
 
-	sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
-	bh := reflect.SliceHeader{Data: sh.Data, Len: sh.Len, Cap: sh.Len}
-
-	return *(*[]byte)(unsafe.Pointer(&bh))
+	p := unsafe.Pointer((*reflect.StringHeader)(unsafe.Pointer(&s)).Data)
+	var b []byte
+	sh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	sh.Data = uintptr(p)
+	sh.Cap = len(s)
+	sh.Len = len(s)
+	return b
 }

utils/unsafe_test.go

@@ -0,0 +1,61 @@
+/*
+Copyright 2021 RadonDB.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBytesToString(t *testing.T) {
+	{
+		bs := []byte{0x61, 0x62}
+		want := "ab"
+		got := BytesToString(bs)
+		assert.Equal(t, want, got)
+	}
+
+	{
+		bs := []byte{}
+		want := ""
+		got := BytesToString(bs)
+		assert.Equal(t, want, got)
+	}
+}
+
+func TestSting(t *testing.T) {
+	{
+		want := []byte{0x61, 0x62}
+		got := StringToBytes("ab")
+		assert.Equal(t, want, got)
+	}
+
+	{
+		want := []byte{}
+		got := StringToBytes("")
+		assert.Equal(t, want, got)
+	}
+}
+
+func TestStingToBytes(t *testing.T) {
+	{
+		want := []byte{0x53, 0x45, 0x4c, 0x45, 0x43, 0x54, 0x20, 0x2a, 0x20, 0x46, 0x52, 0x4f, 0x4d, 0x20, 0x74, 0x32}
+		got := StringToBytes("SELECT * FROM t2")
+		assert.Equal(t, want, got)
+	}
+}