[libpanel] save-dialog: keep window alive during async operations

[Christian Hergert <chergert src gnome org>]

commit 426064815cdb663bf573ea9bbefba0bbddb5819c
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 13 15:22:39 2022 -0700

    save-dialog: keep window alive during async operations
    
    Additionally, this allows the cancel operation to be used later so that
    we can cancel the inflight save operations.
    
    Some wizardry was necessary for the close_request since we'd get called
    (and cancelled) vis the response signal before we can determine if the
    operation is active.

 src/panel-save-dialog.c | 92 ++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 76 insertions(+), 16 deletions(-)
---
diff --git a/src/panel-save-dialog.c b/src/panel-save-dialog.c
index eea4d85..7aa0685 100644
--- a/src/panel-save-dialog.c
+++ b/src/panel-save-dialog.c
@@ -31,11 +31,18 @@
 struct _PanelSaveDialog
 {
   AdwMessageDialog     parent_instance;
+
   GPtrArray           *rows;
+  GCancellable        *cancellable;
+  GTask               *task;
+
   AdwPreferencesPage  *page;
   AdwPreferencesGroup *group;
-  GTask               *task;
+
   guint                close_after_save : 1;
+  guint                discarding : 1;
+  guint                saving : 1;
+  guint                suppress_close : 1;
 };
 
 typedef struct
@@ -84,14 +91,13 @@ panel_save_dialog_response_cancel_cb (PanelSaveDialog *self,
 
   g_assert (PANEL_IS_SAVE_DIALOG (self));
 
-  task = g_steal_pointer (&self->task);
-  g_task_return_new_error (task,
-                           G_IO_ERROR,
-                           G_IO_ERROR_CANCELLED,
-                           "Operation was cancelled");
-  gtk_window_destroy (GTK_WINDOW (self));
-
-  g_clear_object (&task);
+  if ((task = g_steal_pointer (&self->task)))
+    {
+      g_cancellable_cancel (self->cancellable);
+      if (!g_task_get_completed (task))
+        g_task_return_error_if_cancelled (task);
+      g_clear_object (&task);
+    }
 }
 
 static void
@@ -102,6 +108,8 @@ panel_save_dialog_response_discard_cb (PanelSaveDialog *self,
 
   g_assert (PANEL_IS_SAVE_DIALOG (self));
 
+  self->discarding = TRUE;
+
   task = g_steal_pointer (&self->task);
 
   for (guint i = 0; i < self->rows->len; i++)
@@ -112,9 +120,8 @@ panel_save_dialog_response_discard_cb (PanelSaveDialog *self,
       panel_save_delegate_discard (delegate);
     }
 
-  g_task_return_boolean (task, TRUE);
-
-  gtk_window_destroy (GTK_WINDOW (self));
+  if (!g_task_get_completed (task))
+    g_task_return_boolean (task, TRUE);
 
   g_clear_object (&task);
 }
@@ -142,7 +149,8 @@ panel_save_dialog_save_cb (GObject      *object,
     }
   else if (save->close_after_save)
     {
-      panel_save_delegate_close (delegate);
+      if (!g_task_had_error (task))
+        panel_save_delegate_close (delegate);
     }
 
   g_ptr_array_remove (save->delegates, delegate);
@@ -169,6 +177,8 @@ panel_save_dialog_response_save_cb (PanelSaveDialog *self,
   adw_message_dialog_set_response_enabled (ADW_MESSAGE_DIALOG (self), "save", FALSE);
   adw_message_dialog_set_response_enabled (ADW_MESSAGE_DIALOG (self), "discard", FALSE);
 
+  self->saving = TRUE;
+
   save = g_slice_new0 (Save);
   save->close_after_save = self->close_after_save;
   save->delegates = g_ptr_array_new_with_free_func (g_object_unref);
@@ -240,12 +250,47 @@ set_response_visible (AdwMessageDialog *dialog,
   find_button_and_set_visible (GTK_WIDGET (narrow), label, visible);
 }
 
+static gboolean
+panel_save_dialog_close_request_idle_cb (gpointer user_data)
+{
+  PanelSaveDialog *self = user_data;
+
+  g_assert (PANEL_IS_SAVE_DIALOG (self));
+
+  if (self->saving || self->discarding)
+    return G_SOURCE_REMOVE;
+
+  if (!GTK_WINDOW_CLASS (panel_save_dialog_parent_class)->close_request (GTK_WINDOW (self)))
+    gtk_window_destroy (GTK_WINDOW (self));
+
+  return G_SOURCE_REMOVE;
+}
+
+static gboolean
+panel_save_dialog_close_request (GtkWindow *window)
+{
+  PanelSaveDialog *self = (PanelSaveDialog *)window;
+
+  g_assert (PANEL_IS_SAVE_DIALOG (self));
+
+  /* Defer to idle so that we can check if we are actively saving. */
+  if (self->suppress_close)
+    g_idle_add_full (G_PRIORITY_HIGH,
+                     panel_save_dialog_close_request_idle_cb,
+                     g_object_ref (self),
+                     g_object_unref);
+
+  return TRUE;
+}
+
 static void
 panel_save_dialog_dispose (GObject *object)
 {
   PanelSaveDialog *self = (PanelSaveDialog *)object;
 
   g_clear_pointer (&self->rows, g_ptr_array_unref);
+  g_clear_object (&self->cancellable);
+  g_clear_object (&self->task);
 
   G_OBJECT_CLASS (panel_save_dialog_parent_class)->dispose (object);
 }
@@ -293,11 +338,14 @@ panel_save_dialog_class_init (PanelSaveDialogClass *klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
   GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+  GtkWindowClass *window_class = GTK_WINDOW_CLASS (klass);
 
   object_class->dispose = panel_save_dialog_dispose;
   object_class->get_property = panel_save_dialog_get_property;
   object_class->set_property = panel_save_dialog_set_property;
 
+  window_class->close_request = panel_save_dialog_close_request;
+
   /**
    * PanelSaveDialog:close-after-save:
    *
@@ -326,6 +374,7 @@ static void
 panel_save_dialog_init (PanelSaveDialog *self)
 {
   self->rows = g_ptr_array_new ();
+  self->suppress_close = TRUE;
 
   gtk_widget_init_template (GTK_WIDGET (self));
 }
@@ -454,6 +503,8 @@ panel_save_dialog_add_delegate (PanelSaveDialog   *self,
   g_return_if_fail (PANEL_IS_SAVE_DIALOG (self));
   g_return_if_fail (PANEL_IS_SAVE_DELEGATE (delegate));
 
+  panel_save_delegate_set_progress (delegate, 0);
+
   row = panel_save_dialog_row_new (delegate);
   g_signal_connect_object (row,
                            "notify::selected",
@@ -474,8 +525,13 @@ task_completed_cb (PanelSaveDialog *self,
   g_assert (PANEL_IS_SAVE_DIALOG (self));
   g_assert (G_IS_TASK (task));
 
+  self->saving = FALSE;
+  self->discarding = FALSE;
+
   if (self->task == task)
     g_clear_object (&self->task);
+
+  gtk_window_destroy (GTK_WINDOW (self));
 }
 
 void
@@ -491,18 +547,22 @@ panel_save_dialog_run_async (PanelSaveDialog     *self,
 
   g_object_ref_sink (self);
 
-  task = g_task_new (self, cancellable, callback, user_data);
+  if (cancellable == NULL)
+    self->cancellable = g_cancellable_new ();
+  else
+    self->cancellable = g_object_ref (cancellable);
+
+  task = g_task_new (self, self->cancellable, callback, user_data);
   g_task_set_source_tag (task, panel_save_dialog_run_async);
 
   g_signal_connect_object (task,
-                           "notify::complete",
+                           "notify::completed",
                            G_CALLBACK (task_completed_cb),
                            self,
                            G_CONNECT_SWAPPED);
 
   if (self->rows->len == 0)
     {
-      gtk_window_destroy (GTK_WINDOW (self));
       g_task_return_boolean (task, TRUE);
       g_clear_object (&task);
       return;