remove redundant copy in ParseToProtobuf

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go: ['1.20', '1.21']
+        go: ['1.14', '1.15', '1.16', '1.17', '1.18', '1.19', '1.20', '1.21']
         os: ['ubuntu-latest', 'windows-latest']
         include:
         - go: 1.16 # Oldest Go version still tested (Windows requires 1.20+ due to https://github.com/golang/go/issues/57455)

parser/parser.go

@@ -101,7 +101,7 @@ func ScanToProtobuf(input string) (result []byte, err error) {
 }
 
 // ParseToProtobuf - Parses the given SQL statement into a parse tree (Protobuf format)
-func ParseToProtobuf(input string) (result []byte, err error) {
+func ParseToProtobuf(input string) ([]byte, error) {
 	inputC := C.CString(input)
 	defer C.free(unsafe.Pointer(inputC))
 
@@ -110,13 +110,10 @@ func ParseToProtobuf(input string) (result []byte, err error) {
 	defer C.pg_query_free_protobuf_parse_result(resultC)
 
 	if resultC.error != nil {
-		err = newPgQueryError(resultC.error)
-		return
+		return nil, newPgQueryError(resultC.error)
 	}
 
-	result = []byte(C.GoStringN(resultC.parse_tree.data, C.int(resultC.parse_tree.len)))
-
-	return
+	return toBytes(C.GoStringN(resultC.parse_tree.data, C.int(resultC.parse_tree.len))), nil
 }
 
 // DeparseFromProtobuf - Deparses the given Protobuf format parse tree into a SQL statement

parser/string_to_bytes.go

@@ -0,0 +1,19 @@
+//go:build !go1.20
+// +build !go1.20
+
+package parser
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+func toBytes(s string) (b []byte) {
+	pb := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	ps := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	pb.Data = ps.Data
+	pb.Len = ps.Len
+	pb.Cap = ps.Len
+
+	return b
+}

parser/string_to_bytes_go1.20.go

@@ -0,0 +1,14 @@
+//go:build go1.20
+// +build go1.20
+
+package parser
+
+import "unsafe"
+
+func toBytes(s string) (b []byte) {
+	if s == "" {
+		return nil
+	}
+
+	return unsafe.Slice(unsafe.StringData(s), len(s))
+}