Finalizers for native lightweight objects

Author: dvd-bnc

lib/backend/fs.dart

@@ -241,7 +241,13 @@ class TransferFileOperation extends BaseFileSystemOperation<bool> {
   }
 }
 
-extension type File._(Pointer<GFile> _handle) implements Object {
+final NativeFinalizer _finalizer = NativeFinalizer(Native.addressOf(obj_unref));
+
+class File implements Finalizable {
+  File._(this._handle) {
+    _finalizer.attach(this, _handle.cast());
+  }
+
   static File fromRawPath(Pointer<Char> path) {
     final res = file_new(path);
 
@@ -257,6 +263,8 @@ extension type File._(Pointer<GFile> _handle) implements Object {
     });
   }
 
+  final Pointer<GFile> _handle;
+
   String get path => file_path(_handle).cast<Utf8>().toDartString();
   File? get parent {
     final parent = file_parent(_handle);
@@ -359,7 +367,12 @@ extension type File._(Pointer<GFile> _handle) implements Object {
   }
 }
 
-extension type FileInfo._(Pointer<GFileInfo> _handle) {
+class FileInfo implements Finalizable {
+  FileInfo._(this._handle) {
+    _finalizer.attach(this, _handle.cast());
+  }
+
+  final Pointer<GFileInfo> _handle;
   String? getName() {
     final name = fileinfo_get_name(_handle);
     if (name == nullptr) return null;

lib/backend/fs_native.dart

@@ -33,6 +33,9 @@ final class GList extends Struct {
   external final Pointer<GList> previous;
 }
 
+@Native<Void Function(Pointer<Void>)>()
+external void obj_unref(Pointer<Void> obj);
+
 @Native<Pointer<GCancellable> Function()>()
 external Pointer<GCancellable> cancellable_new();
 

src/src/lib.zig

@@ -482,3 +482,8 @@ pub export fn error_domain_name(err: *c.GError) [*c]const u8 {
 pub export fn list_destroy(list: [*c]c.GList) void {
     c.g_list_free(list);
 }
+
+// -------- MEMORY -------- //
+pub export fn obj_unref(obj: ?*anyopaque) void {
+    c.g_object_unref(obj);
+}