[gnome-software/wip/installed_updates: 8/16] update dialog: Implement better back button state tracking

[Kalev Lember <klember src gnome org>]

commit 58bd1e30d3e474de0384f70ac491f6bf324489bc
Author: Kalev Lember <kalevlember gmail com>
Date:   Tue Apr 29 21:41:17 2014 +0200

    update dialog: Implement better back button state tracking
    
    This adds a GQueue based stack for keeping track of the previous dialog
    states.

 src/gs-update-dialog.c |   59 +++++++++++++++++++++++++++++++++++++++++------
 1 files changed, 51 insertions(+), 8 deletions(-)
---
diff --git a/src/gs-update-dialog.c b/src/gs-update-dialog.c
index 58bf3fc..1150b51 100644
--- a/src/gs-update-dialog.c
+++ b/src/gs-update-dialog.c
@@ -28,8 +28,15 @@
 #include "gs-markdown.h"
 #include "gs-utils.h"
 
+typedef struct {
+       gchar           *title;
+       gchar           *stack_page;
+       GtkWidget       *focus;
+} BackEntry;
+
 struct _GsUpdateDialogPrivate
 {
+       GQueue          *back_entry_stack;
        GsApp           *app;
        GtkWidget       *box_header;
        GtkWidget       *button_back;
@@ -46,6 +53,28 @@ struct _GsUpdateDialogPrivate
 G_DEFINE_TYPE_WITH_PRIVATE (GsUpdateDialog, gs_update_dialog, GTK_TYPE_DIALOG)
 
 static void
+save_back_entry (GsUpdateDialog *dialog)
+{
+       GsUpdateDialogPrivate *priv = gs_update_dialog_get_instance_private (dialog);
+       BackEntry *entry;
+
+       entry = g_slice_new0 (BackEntry);
+       entry->stack_page = g_strdup (gtk_stack_get_visible_child_name (GTK_STACK (priv->stack)));
+       entry->title = g_strdup (gtk_window_get_title (GTK_WINDOW (dialog)));
+       entry->focus = gtk_window_get_focus (GTK_WINDOW (dialog));
+
+       g_queue_push_head (priv->back_entry_stack, entry);
+}
+
+static void
+back_entry_free (BackEntry *entry)
+{
+       g_free (entry->stack_page);
+       g_free (entry->title);
+       g_slice_free (BackEntry, entry);
+}
+
+static void
 set_updates_description_ui (GsUpdateDialog *dialog, GsApp *app)
 {
        GsUpdateDialogPrivate *priv = gs_update_dialog_get_instance_private (dialog);
@@ -86,6 +115,9 @@ set_updates_description_ui (GsUpdateDialog *dialog, GsApp *app)
        gtk_label_set_label (GTK_LABEL (priv->label_name), gs_app_get_name (app));
        gtk_label_set_label (GTK_LABEL (priv->label_summary), gs_app_get_summary (app));
        g_free (update_desc);
+
+       /* show the back button if needed */
+       gtk_widget_set_visible (priv->button_back, !g_queue_is_empty (priv->back_entry_stack));
 }
 
 static void
@@ -97,10 +129,13 @@ row_activated_cb (GtkListBox *list_box,
        GsApp *app = NULL;
 
        app = GS_APP (g_object_get_data (G_OBJECT (gtk_bin_get_child (GTK_BIN (row))), "app"));
+
+       /* save the current stack state for the back button */
+       save_back_entry (dialog);
+
        /* setup package view */
        gtk_stack_set_visible_child_name (GTK_STACK (priv->stack), "package-details");
        set_updates_description_ui (dialog, app);
-       gtk_widget_show (priv->button_back);
 }
 
 void
@@ -119,9 +154,6 @@ gs_update_dialog_set_app (GsUpdateDialog *dialog, GsApp *app)
        /* set update header */
        set_updates_description_ui (dialog, app);
 
-       /* only OS updates can go back, and only on selection */
-       gtk_widget_hide (priv->button_back);
-
        /* set update description */
        if (kind == GS_APP_KIND_OS_UPDATE) {
                GPtrArray *related;
@@ -201,12 +233,17 @@ static void
 button_back_cb (GtkWidget *widget, GsUpdateDialog *dialog)
 {
        GsUpdateDialogPrivate *priv = gs_update_dialog_get_instance_private (dialog);
+       BackEntry *entry;
 
-       /* return to the list view */
-       gtk_widget_hide (priv->button_back);
-       gtk_stack_set_visible_child_name (GTK_STACK (priv->stack), "os-update-list");
+       /* return to the previous view */
+       entry = g_queue_pop_head (priv->back_entry_stack);
+       gtk_stack_set_visible_child_name (GTK_STACK (priv->stack), entry->stack_page);
+       gtk_window_set_title (GTK_WINDOW (dialog), entry->title);
+       if (entry->focus)
+               gtk_widget_grab_focus (entry->focus);
+       back_entry_free (entry);
 
-       gtk_window_set_title (GTK_WINDOW (dialog), gs_app_get_name (priv->app));
+       gtk_widget_set_visible (priv->button_back, !g_queue_is_empty (priv->back_entry_stack));
 }
 
 static void
@@ -233,6 +270,10 @@ gs_update_dialog_finalize (GObject *object)
        GsUpdateDialog *dialog = GS_UPDATE_DIALOG (object);
        GsUpdateDialogPrivate *priv = gs_update_dialog_get_instance_private (dialog);
 
+       if (priv->back_entry_stack != NULL) {
+               g_queue_free_full (priv->back_entry_stack, (GDestroyNotify) back_entry_free);
+               priv->back_entry_stack = NULL;
+       }
        g_clear_object (&priv->app);
 
        G_OBJECT_CLASS (gs_update_dialog_parent_class)->finalize (object);
@@ -246,6 +287,8 @@ gs_update_dialog_init (GsUpdateDialog *dialog)
 
        gtk_widget_init_template (GTK_WIDGET (dialog));
 
+       priv->back_entry_stack = g_queue_new ();
+
        g_signal_connect (GTK_LIST_BOX (priv->list_box), "row-activated",
                          G_CALLBACK (row_activated_cb), dialog);
        gtk_list_box_set_header_func (GTK_LIST_BOX (priv->list_box),