Improve support for opening HTTP URIs

While all GVfs files implement the mountable interface,
mounting may not actually achieve anything.

fiv-view.c

@@ -1095,24 +1095,24 @@ save_as(FivView *self, cairo_surface_t *frame)
 	gtk_file_chooser_set_do_overwrite_confirmation(chooser, TRUE);
 
 	GFile *file = g_file_new_for_uri(self->uri);
-	const gchar *path = g_file_peek_path(file);
-	// TODO(p): Use g_file_info_get_display_name().
-	gchar *basename = g_filename_display_basename(path ? path : self->uri);
+	GFileInfo *info =
+		g_file_query_info(file, G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME,
+			G_FILE_QUERY_INFO_NONE, NULL, NULL);
 
 	// Note that GTK+'s save dialog is too stupid to automatically change
 	// the extension when user changes the filter. Presumably,
 	// gtk_file_chooser_set_extra_widget() can be used to circumvent this.
-	gchar *name =
-		g_strdup_printf(frame ? "%s.frame.webp" : "%s.webp", basename);
+	const char *basename = info ? g_file_info_get_display_name(info) : "image";
+	gchar *name = g_strconcat(basename, frame ? "-frame.webp" : ".webp", NULL);
 	gtk_file_chooser_set_current_name(chooser, name);
 	g_free(name);
-	if (path) {
-		gchar *dirname = g_path_get_dirname(path);
-		gtk_file_chooser_set_current_folder(chooser, dirname);
-		g_free(dirname);
+	if (g_file_peek_path(file)) {
+		GFile *parent = g_file_get_parent(file);
+		(void) gtk_file_chooser_set_current_folder_file(chooser, parent, NULL);
+		g_object_unref(parent);
 	}
-	g_free(basename);
 	g_object_unref(file);
+	g_clear_object(&info);
 
 	// This is the best general format: supports lossless encoding, animations,
 	// alpha channel, and Exif and ICC profile metadata.

fiv.c

@@ -913,27 +913,44 @@ on_item_activated(G_GNUC_UNUSED FivBrowser *browser, GFile *location,
 static void open_any_file(GFile *file, gboolean force_browser);
 
 static void
-on_mounted_enclosing(GObject *source_object, GAsyncResult *res,
-	G_GNUC_UNUSED gpointer user_data)
+on_mounted_enclosing(
+	GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
 	GFile *file = G_FILE(source_object);
 	GError *error = NULL;
-	if (!g_file_mount_enclosing_volume_finish(file, res, &error))
+	if (g_file_mount_enclosing_volume_finish(file, res, &error))
+		goto retry;
+
+	if (!g_error_matches(error, G_IO_ERROR, G_IO_ERROR_ALREADY_MOUNTED)) {
 		show_error_dialog(error);
-	else
-		open_any_file(file, FALSE);
+		return;
+	}
+
+	// The "http" scheme doesn't behave nicely, make a leap of faith.
+	g_error_free(error);
+	if (g_file_query_file_type(file, G_FILE_QUERY_INFO_NONE, NULL) ==
+		G_FILE_TYPE_UNKNOWN) {
+		gchar *uri = g_file_get_uri(file);
+		open_image(uri);
+		g_free(uri);
+		return;
+	}
+
+retry:
+	open_any_file(file, (gboolean) (gintptr) user_data);
 }
 
 static void
 open_any_file(GFile *file, gboolean force_browser)
 {
+	// Various GVfs schemes may need mounting.
 	GFileType type = g_file_query_file_type(file, G_FILE_QUERY_INFO_NONE, NULL);
 	if (type == G_FILE_TYPE_UNKNOWN &&
 		G_FILE_GET_IFACE(file)->mount_enclosing_volume) {
 		// TODO(p): At least provide some kind of indication.
 		GMountOperation *op = gtk_mount_operation_new(GTK_WINDOW(g.window));
 		g_file_mount_enclosing_volume(file, G_MOUNT_MOUNT_NONE, op, NULL,
-			on_mounted_enclosing, NULL);
+			on_mounted_enclosing, (gpointer) (gintptr) force_browser);
 		g_object_unref(op);
 		return;
 	}