[gnome-software] Improve back button handling

[Matthias Clasen <matthiasc src gnome org>]

commit b491899211122a783a57df1d6cd5fe7e53726ee9
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Aug 31 19:05:33 2013 -0400

    Improve back button handling
    
    Add a stack, so we can go back from an application to the category
    to the overview.

 src/gs-shell-category.c |    6 ++++++
 src/gs-shell-category.h |    1 +
 src/gs-shell.c          |   36 ++++++++++++++++++++++++++++++++++--
 3 files changed, 41 insertions(+), 2 deletions(-)
---
diff --git a/src/gs-shell-category.c b/src/gs-shell-category.c
index 298709c..706ce34 100644
--- a/src/gs-shell-category.c
+++ b/src/gs-shell-category.c
@@ -232,6 +232,12 @@ gs_shell_category_set_category (GsShellCategory *shell, GsCategory *category)
         gs_shell_category_populate_filtered (shell, subcategory);
 }
 
+GsCategory *
+gs_shell_category_get_category (GsShellCategory *shell)
+{
+        return shell->priv->category;
+}
+
 static void
 gs_shell_category_class_init (GsShellCategoryClass *klass)
 {
diff --git a/src/gs-shell-category.h b/src/gs-shell-category.h
index 63416f4..d732b4c 100644
--- a/src/gs-shell-category.h
+++ b/src/gs-shell-category.h
@@ -56,6 +56,7 @@ GType          gs_shell_category_get_type     (void);
 GsShellCategory        *gs_shell_category_new          (void);
 void            gs_shell_category_set_category (GsShellCategory *shell_category,
                                                 GsCategory      *category);
+GsCategory      *gs_shell_category_get_category (GsShellCategory *shell_category);
 void            gs_shell_category_refresh      (GsShellCategory *shell_category);
 void             gs_shell_category_setup        (GsShellCategory *shell_category,
                                                  GsShell         *shell,
diff --git a/src/gs-shell.c b/src/gs-shell.c
index c089ae4..6547f77 100644
--- a/src/gs-shell.c
+++ b/src/gs-shell.c
@@ -36,6 +36,12 @@ static void  gs_shell_finalize       (GObject        *object);
 
 #define GS_SHELL_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), GS_TYPE_SHELL, GsShellPrivate))
 
+typedef struct {
+        GsShellMode mode;
+        GsApp *app;
+        GsCategory *category;
+} BackEntry;
+
 struct GsShellPrivate
 {
        gboolean                 ignore_primary_buttons;
@@ -49,7 +55,7 @@ struct GsShellPrivate
        GsShellDetails          *shell_details;
        GsShellCategory         *shell_category;
        GtkBuilder              *builder;
-       GsShellMode              tab_back_id;
+       GSList                  *back_entry_stack;
 };
 
 G_DEFINE_TYPE (GsShell, gs_shell, G_TYPE_OBJECT)
@@ -151,13 +157,37 @@ gs_shell_overview_button_cb (GtkWidget *widget, GsShell *shell)
        gs_shell_change_mode (shell, mode, NULL, NULL);
 }
 
+static void
+save_back_entry (GsShell *shell)
+{
+       GsShellPrivate *priv = shell->priv;
+        BackEntry *entry;
+
+        entry = g_new0 (BackEntry, 1);
+        entry->mode = priv->mode;
+
+        if (priv->mode == GS_SHELL_MODE_CATEGORY)
+                entry->category = gs_shell_category_get_category (priv->shell_category);
+
+        priv->back_entry_stack = g_slist_prepend (priv->back_entry_stack, entry);
+}
+
 /**
  * gs_shell_back_button_cb:
  **/
 static void
 gs_shell_back_button_cb (GtkWidget *widget, GsShell *shell)
 {
-       gs_shell_change_mode (shell, shell->priv->tab_back_id, NULL, NULL);
+       GsShellPrivate *priv = shell->priv;
+        BackEntry *entry;
+
+        g_assert (priv->back_entry_stack);
+        entry = priv->back_entry_stack->data;
+        priv->back_entry_stack = g_slist_remove (priv->back_entry_stack, entry);
+
+       gs_shell_change_mode (shell, entry->mode, entry->app, entry->category);
+
+        g_free (entry);
 }
 
 static void
@@ -420,12 +450,14 @@ gs_shell_get_mode (GsShell *shell)
 void
 gs_shell_show_app (GsShell *shell, GsApp *app)
 {
+        save_back_entry (shell);
         gs_shell_change_mode (shell, GS_SHELL_MODE_DETAILS, app, NULL);
 }
 
 void
 gs_shell_show_category (GsShell *shell, GsCategory *category)
 {
+        save_back_entry (shell);
         gs_shell_change_mode (shell, GS_SHELL_MODE_CATEGORY, NULL, category);
 }