Add async read/write file helpers

gajim/common/helpers.py

@@ -1738,3 +1738,51 @@ class Observable:
                 self._callbacks[signal_name].remove(func)
                 continue
             func()(self, signal_name, *args, **kwargs)
+
+
+def write_file_async(path, data, callback, user_data=None):
+    file = Gio.File.new_for_path(str(path))
+    file.create_async(Gio.FileCreateFlags.PRIVATE,
+                          GLib.PRIORITY_DEFAULT,
+                          None,
+                          _on_file_created,
+                          (callback, data, user_data))
+
+def _on_file_created(file, result, user_data):
+    callback, data, user_data = user_data
+    try:
+        outputstream = file.create_finish(result)
+    except GLib.Error as error:
+        callback(False, error, user_data)
+        return
+
+    outputstream.write_all_async(data,
+                                 GLib.PRIORITY_DEFAULT,
+                                 None,
+                                 _on_write_finished,
+                                 (callback, user_data))
+
+def _on_write_finished(outputstream, result, user_data):
+    callback, user_data = user_data
+    try:
+        successful, _bytes_written = outputstream.write_all_finish(result)
+    except GLib.Error as error:
+        callback(False, error, user_data)
+    else:
+        callback(successful, None, user_data)
+
+
+def load_file_async(path, callback, user_data=None):
+    file = Gio.File.new_for_path(str(path))
+    file.load_contents_async(None,
+                             _on_load_finished,
+                             (callback, user_data))
+
+def _on_load_finished(file, result, user_data):
+    callback, user_data = user_data
+    try:
+        _successful, contents, _etag = file.load_contents_finish(result)
+    except GLib.Error as error:
+        callback(None, error, user_data)
+    else:
+        callback(contents, None, user_data)