feat(helper)[image]: avoid nested asyncs

src/Services/Helpers/Image.vala

@@ -6,6 +6,10 @@ public class Tuba.Helper.Image {
 			throw new Oopsie.INSTANCE (@"Server returned $(msg.reason_phrase)");
 		}
 
+		//  if (msg.response_headers.get_content_type (null) == "image/gif") {
+		//  	//  return Gtk.MediaFile.for_input_stream (in_stream);
+		//  }
+
 		return Gdk.Texture.for_pixbuf ((yield new Gdk.Pixbuf.from_stream_async (in_stream)).apply_embedded_orientation ());
 	}
 
@@ -49,6 +53,17 @@ public class Tuba.Helper.Image {
 		}
 	}
 
+	private static async Gdk.Paintable? fetch_paintable (string url) {
+		var download_msg = new Soup.Message ("GET", url);
+		try {
+			var in_stream = yield session.send_async (download_msg, 0, null);
+			return yield decode (download_msg, in_stream);
+		} catch (Error e) {
+			warning (@"Failed to download image at \"$url\": $(e.message)");
+			return null;
+		}
+	}
+
 	public static void request_paintable (string? url, string? blurhash, owned OnItemChangedFn cb) {
 		if (url == null || url == "") return;
 		new Helper.Image ();
@@ -64,30 +79,9 @@ public class Tuba.Helper.Image {
 			});
 		}
 
-		var download_msg = new Soup.Message ("GET", url);
-		session.send_async.begin (download_msg, 0, null, (obj, res) => {
-			try {
-				var in_stream = session.send_async.end (res);
-
-				decode.begin (download_msg, in_stream, (obj, async_res) => {
-					has_loaded = true;
-					Gdk.Paintable? paintable = null;
-					try {
-						paintable = decode.end (async_res);
-					} catch (Error e) {
-						warning (@"Failed to download image at \"$url\": $(e.message)");
-						cb (null);
-
-						return;
-					}
-
-					cb (paintable);
-				});
-			} catch (GLib.Error e) {
-				warning (e.message);
-				has_loaded = true;
-				cb (null);
-			}
+		fetch_paintable.begin (url, (obj, res) => {
+			cb (fetch_paintable.end (res));
+			has_loaded = true;
 		});
 	}
 }