QueryStable with err

Author: auxten

chdbstable/chdb.go

@@ -7,40 +7,61 @@ package chdbstable
 */
 import "C"
 import (
+	"errors"
 	"runtime"
 	"unsafe"
 )
 
-// LocalResult mirrors the C struct local_result in Go.
+// ChdbError is returned when the C function returns an error.
+type ChdbError struct {
+	msg string
+}
+
+func (e *ChdbError) Error() string {
+	return e.msg
+}
+
+// ErrNilResult is returned when the C function returns a nil pointer.
+var ErrNilResult = errors.New("chDB C function returned nil pointer")
+
+
+// LocalResult mirrors the C struct local_result_v2 in Go.
 type LocalResult struct {
-	cResult *C.struct_local_result
+	cResult *C.struct_local_result_v2
 }
 
 // newLocalResult creates a new LocalResult and sets a finalizer to free C memory.
-func newLocalResult(cResult *C.struct_local_result) *LocalResult {
+func newLocalResult(cResult *C.struct_local_result_v2) *LocalResult {
 	result := &LocalResult{cResult: cResult}
 	runtime.SetFinalizer(result, freeLocalResult)
 	return result
 }
 
 // freeLocalResult is called by the garbage collector.
 func freeLocalResult(result *LocalResult) {
-	C.free_result(result.cResult)
+	C.free_result_v2(result.cResult)
 }
 
-// QueryStable calls the C function query_stable.
-func QueryStable(argc int, argv []string) *LocalResult {
+// QueryStable calls the C function query_stable_v2.
+func QueryStable(argc int, argv []string) (result *LocalResult, err error) {
 	cArgv := make([]*C.char, len(argv))
 	for i, s := range argv {
 		cArgv[i] = C.CString(s)
 		defer C.free(unsafe.Pointer(cArgv[i]))
 	}
 
-	cResult := C.query_stable(C.int(argc), &cArgv[0])
-	return newLocalResult(cResult)
+	cResult := C.query_stable_v2(C.int(argc), &cArgv[0])
+	if cResult == nil {
+		// According to the C ABI of chDB, it is not possible to return a nil pointer.
+		return nil, ErrNilResult
+	}
+	if cResult.error_message != nil {
+		return nil, &ChdbError{msg: C.GoString(cResult.error_message)}
+	}
+	return newLocalResult(cResult), nil
 }
 
-// Accessor methods to access fields of the local_result struct.
+// Accessor methods to access fields of the local_result_v2 struct.
 func (r *LocalResult) Buf() []byte {
 	if r.cResult == nil {
 		return nil
@@ -87,3 +108,10 @@ func (r *LocalResult) BytesRead() uint64 {
 	}
 	return uint64(r.cResult.bytes_read)
 }
+
+func (r *LocalResult) Error() string {
+	if r.cResult == nil {
+		return ""
+	}
+	return C.GoString(r.cResult.err)
+}