[tepl] Tab loading: cancel operation on tab ::destroy

[Sébastien Wilmet <swilmet src gnome org>]

commit 116445d464b3103ff2f0024de895b630592e1966
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon May 25 12:38:22 2020 +0200

    Tab loading: cancel operation on tab ::destroy
    
    When there is a request to destroy the tab (usually when the user
    presses the close button), cancel the loading operation.

 tepl/tepl-tab-loading.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)
---
diff --git a/tepl/tepl-tab-loading.c b/tepl/tepl-tab-loading.c
index 7d3fd48..ce8c43b 100644
--- a/tepl/tepl-tab-loading.c
+++ b/tepl/tepl-tab-loading.c
@@ -27,7 +27,8 @@ load_file_cb (GObject      *source_object,
                tepl_file_add_uri_to_recent_manager (file);
        }
 
-       if (error != NULL)
+       if (error != NULL &&
+           !g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
        {
                TeplInfoBar *info_bar;
 
@@ -37,10 +38,9 @@ load_file_cb (GObject      *source_object,
 
                tepl_tab_add_info_bar (tab, GTK_INFO_BAR (info_bar));
                gtk_widget_show (GTK_WIDGET (info_bar));
-
-               g_clear_error (&error);
        }
 
+       g_clear_error (&error);
        g_object_unref (loader);
        g_object_unref (tab);
 }
@@ -65,6 +65,7 @@ tepl_tab_load_file (TeplTab *tab,
        TeplBuffer *buffer;
        TeplFile *file;
        TeplFileLoader *loader;
+       GCancellable *cancellable;
 
        g_return_if_fail (TEPL_IS_TAB (tab));
        g_return_if_fail (G_IS_FILE (location));
@@ -75,9 +76,23 @@ tepl_tab_load_file (TeplTab *tab,
        tepl_file_set_location (file, location);
        loader = tepl_file_loader_new (buffer, file);
 
+       cancellable = g_cancellable_new ();
+
+       /* If there is a request to destroy the tab, it's pointless to continue
+        * loading the file. So, cancel the operation when the tab is destroyed,
+        * to free up resources for other operations.
+        */
+       g_signal_connect_object (tab,
+                                "destroy",
+                                G_CALLBACK (g_cancellable_cancel),
+                                cancellable,
+                                G_CONNECT_SWAPPED);
+
        tepl_file_loader_load_async (loader,
                                     G_PRIORITY_DEFAULT,
-                                    NULL, /* cancellable */
+                                    cancellable,
                                     load_file_cb,
                                     g_object_ref (tab));
+
+       g_object_unref (cancellable);
 }