[nautilus] canvas-container: rework canvas item focusing

[Ernestas Kulik <ernestask src gnome org>]

commit dea197990d1ab931dd97a91bc5c696f859b5eb24
Author: Ernestas Kulik <ernestask src gnome org>
Date:   Thu Apr 28 20:53:28 2016 +0300

    canvas-container: rework canvas item focusing
    
     - Currently, atk_focus_tracker_notify() is used, which is deprecated as
       of ATK 2.9.4. Using atk_object_notify_state_change() with
       ATK_STATE_FOCUSED is recommended. The deprecated call was replaced.
    
     - For every selection, the previous one should get unfocused.
       Currently, only the keyboard focus is tracked. That was extended to
       mouse focus with a flag for keyboard focus for indicator rendering.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762236

 src/nautilus-canvas-container.c |  112 ++++++++++++++++++++-------------------
 src/nautilus-canvas-private.h   |    7 ++-
 2 files changed, 62 insertions(+), 57 deletions(-)
---
diff --git a/src/nautilus-canvas-container.c b/src/nautilus-canvas-container.c
index 2f0bd3b..cf21a2e 100644
--- a/src/nautilus-canvas-container.c
+++ b/src/nautilus-canvas-container.c
@@ -754,7 +754,7 @@ keyboard_icon_reveal_timeout_callback (gpointer data)
         * this wouldn't actually be an improvement 
         * (see bugzilla.gnome.org 40612).
         */
-       if (icon == container->details->keyboard_focus
+       if (icon == container->details->focus
            || icon->is_selected) {
                reveal_icon (container, icon);
        }
@@ -792,45 +792,54 @@ schedule_keyboard_icon_reveal (NautilusCanvasContainer *container,
                                 container);
 }
 
-static void
-clear_keyboard_focus (NautilusCanvasContainer *container)
+static void inline
+emit_atk_object_notify_focused (NautilusCanvasIcon *icon,
+                               gboolean focused)
 {
-        if (container->details->keyboard_focus != NULL) {
-               eel_canvas_item_set (EEL_CANVAS_ITEM (container->details->keyboard_focus->item),
-                                    "highlighted_as_keyboard_focus", 0,
-                                    NULL);
-       }
-       
-       container->details->keyboard_focus = NULL;
+       AtkObject *atk_object = atk_gobject_accessible_for_object (G_OBJECT (icon->item));
+       atk_object_notify_state_change (atk_object, ATK_STATE_FOCUSED, focused);
 }
 
-static void inline
-emit_atk_focus_tracker_notify (NautilusCanvasIcon *icon)
+static void
+clear_focus (NautilusCanvasContainer *container)
 {
-       AtkObject *atk_object = atk_gobject_accessible_for_object (G_OBJECT (icon->item));
-       atk_focus_tracker_notify (atk_object);
+       if (container->details->focus != NULL) {
+               if (container->details->keyboard_focus) {
+                       eel_canvas_item_set (EEL_CANVAS_ITEM (container->details->focus->item),
+                                            "highlighted_as_keyboard_focus", 0,
+                                            NULL);
+               } else {
+                       emit_atk_object_notify_focused (container->details->focus, FALSE);
+               }
+       }
+
+       container->details->focus = NULL;
 }
 
-/* Set @icon as the icon currently selected for keyboard operations. */
+/* Set @icon as the icon currently focused for accessibility. */
 static void
-set_keyboard_focus (NautilusCanvasContainer *container,
-                   NautilusCanvasIcon *icon)
+set_focus (NautilusCanvasContainer *container,
+          NautilusCanvasIcon *icon,
+          gboolean keyboard_focus)
 {
        g_assert (icon != NULL);
 
-       if (icon == container->details->keyboard_focus) {
+       if (icon == container->details->focus) {
                return;
        }
 
-       clear_keyboard_focus (container);
+       clear_focus (container);
 
-       container->details->keyboard_focus = icon;
+       container->details->focus = icon;
+       container->details->keyboard_focus = keyboard_focus;
 
-       eel_canvas_item_set (EEL_CANVAS_ITEM (container->details->keyboard_focus->item),
-                            "highlighted_as_keyboard_focus", 1,
-                            NULL);
-
-       emit_atk_focus_tracker_notify (icon);
+       if (keyboard_focus) {
+               eel_canvas_item_set (EEL_CANVAS_ITEM (container->details->focus->item),
+                                    "highlighted_as_keyboard_focus", 1,
+                                    NULL);
+       } else {
+               emit_atk_object_notify_focused (container->details->focus, TRUE);
+       }
 }
 
 static void
@@ -2093,10 +2102,6 @@ select_range (NautilusCanvasContainer *container,
                }
                
        }
-       
-       if (selection_changed && icon2 != NULL) {
-               emit_atk_focus_tracker_notify (icon2);
-       }
        return selection_changed;
 }
 
@@ -2119,7 +2124,6 @@ select_one_unselect_others (NautilusCanvasContainer *container,
        }
        
        if (selection_changed && icon_to_select != NULL) {
-               emit_atk_focus_tracker_notify (icon_to_select);
                reveal_icon (container, icon_to_select);
        }
        return selection_changed;
@@ -3293,14 +3297,12 @@ keyboard_move_to (NautilusCanvasContainer *container,
                return;
        }
 
+       set_focus (container, icon, TRUE);
+
        if (event != NULL &&
            (event->state & GDK_CONTROL_MASK) != 0 &&
            (event->state & GDK_SHIFT_MASK) == 0) {
-               /* Move the keyboard focus. Use Control modifier
-                * rather than Alt to avoid Sawfish conflict.
-                */
-               set_keyboard_focus (container, icon);
-               container->details->keyboard_rubberband_start = NULL;
+               clear_keyboard_rubberband_start (container);
        } else if (event != NULL &&
                   ((event->state & GDK_CONTROL_MASK) != 0 ||
                    !container->details->auto_layout) &&
@@ -3312,8 +3314,6 @@ keyboard_move_to (NautilusCanvasContainer *container,
                        set_keyboard_rubberband_start (container, from);
                } 
 
-               set_keyboard_focus (container, icon);
-
                if (icon && container->details->keyboard_rubberband_start) {
                        rect = get_rubberband (container->details->keyboard_rubberband_start,
                                               icon);
@@ -3331,15 +3331,12 @@ keyboard_move_to (NautilusCanvasContainer *container,
                        container->details->range_selection_base_icon = icon;
                } 
 
-               set_keyboard_focus (container, icon);
-
                if (select_range (container, start_icon, icon, TRUE)) {
                        g_signal_emit (container,
                                       signals[SELECTION_CHANGED], 0);
                }
        } else {
-               /* Select icons and get rid of the special keyboard focus. */
-               clear_keyboard_focus (container);
+               /* Select icon. */
                clear_keyboard_rubberband_start (container);
                
                container->details->range_selection_base_icon = icon;
@@ -3430,7 +3427,7 @@ keyboard_arrow_key (NautilusCanvasContainer *container,
         * If there's multiple selection, use the icon farthest toward the end.
         */
        
-       from = container->details->keyboard_focus;
+       from = container->details->focus;
 
        if (from == NULL) {
                if (has_multiple_selection (container)) {
@@ -3665,18 +3662,18 @@ keyboard_space (NautilusCanvasContainer *container,
        NautilusCanvasIcon *icon;
        
        if (!has_selection (container) &&
-           container->details->keyboard_focus != NULL) {
+           container->details->focus != NULL) {
                keyboard_move_to (container,
-                                 container->details->keyboard_focus,
+                                 container->details->focus,
                                  NULL, NULL);
        } else if ((event->state & GDK_CONTROL_MASK) != 0 &&
                   (event->state & GDK_SHIFT_MASK) == 0) {
                /* Control-space toggles the selection state of the current icon. */
-               if (container->details->keyboard_focus != NULL) {
-                       icon_toggle_selected (container, container->details->keyboard_focus);
+               if (container->details->focus != NULL) {
+                       icon_toggle_selected (container, container->details->focus);
                        g_signal_emit (container, signals[SELECTION_CHANGED], 0);
-                       if  (container->details->keyboard_focus->is_selected) {
-                               container->details->range_selection_base_icon = 
container->details->keyboard_focus;
+                       if  (container->details->focus->is_selected) {
+                               container->details->range_selection_base_icon = container->details->focus;
                        } 
                } else {
                        icon = find_best_selected_icon (container,
@@ -3690,7 +3687,7 @@ keyboard_space (NautilusCanvasContainer *container,
                                                           NULL);
                        }
                        if (icon != NULL) {
-                               set_keyboard_focus (container, icon);
+                               set_focus (container, icon, TRUE);
                        }
                }
        } else if ((event->state & GDK_SHIFT_MASK) != 0) {
@@ -3994,7 +3991,6 @@ button_press_event (GtkWidget *widget,
         container->details->button_down_time = event->time;
        
         /* Forget about the old keyboard selection now that we've started mousing. */
-        clear_keyboard_focus (container);
        clear_keyboard_rubberband_start (container);
 
        if (event->type == GDK_2BUTTON_PRESS || event->type == GDK_3BUTTON_PRESS) {
@@ -4013,6 +4009,8 @@ button_press_event (GtkWidget *widget,
                return TRUE;
        }
 
+       clear_focus (container);
+
        if (event->button == DRAG_BUTTON &&
            event->type == GDK_BUTTON_PRESS) {
                /* Clear the last click icon for double click */
@@ -5349,6 +5347,8 @@ handle_canvas_button_press (NautilusCanvasContainer *container,
            (event->state & GDK_SHIFT_MASK) != 0) {
                NautilusCanvasIcon *start_icon;
 
+               set_focus (container, icon, FALSE);
+
                start_icon = details->range_selection_base_icon;
                if (start_icon == NULL || !start_icon->is_selected) {
                        start_icon = icon;
@@ -5360,6 +5360,8 @@ handle_canvas_button_press (NautilusCanvasContainer *container,
                                       signals[SELECTION_CHANGED], 0);
                }
        } else if (!details->icon_selected_on_button_down) {
+               set_focus (container, icon, FALSE);
+
                details->range_selection_base_icon = icon;
                if (button_event_modifies_selection (event)) {
                        icon_toggle_selected (container, icon);
@@ -5450,7 +5452,7 @@ nautilus_canvas_container_clear (NautilusCanvasContainer *container)
                return;
        }
 
-       clear_keyboard_focus (container);
+       clear_focus (container);
        clear_keyboard_rubberband_start (container);
        unschedule_keyboard_icon_reveal (container);
        set_pending_icon_to_reveal (container, NULL);
@@ -5671,12 +5673,12 @@ icon_destroy (NautilusCanvasContainer *container,
 
        was_selected = icon->is_selected;
 
-       if (details->keyboard_focus == icon ||
-           details->keyboard_focus == NULL) {
+       if (details->focus == icon ||
+           details->focus == NULL) {
                if (icon_to_focus != NULL) {
-                       set_keyboard_focus (container, icon_to_focus);
+                       set_focus (container, icon_to_focus, TRUE);
                } else {
-                       clear_keyboard_focus (container);
+                       clear_focus (container);
                }
        }
        
diff --git a/src/nautilus-canvas-private.h b/src/nautilus-canvas-private.h
index 8e9f7c5..6b44952 100644
--- a/src/nautilus-canvas-private.h
+++ b/src/nautilus-canvas-private.h
@@ -122,8 +122,11 @@ struct NautilusCanvasContainerDetails {
        GList *selection;
        GHashTable *icon_set;
 
-       /* Current icon for keyboard navigation. */
-       NautilusCanvasIcon *keyboard_focus;
+       /* Currently focused icon for accessibility. */
+       NautilusCanvasIcon *focus;
+       gboolean keyboard_focus;
+
+       /* Starting icon for keyboard rubberbanding. */
        NautilusCanvasIcon *keyboard_rubberband_start;
 
        /* Current icon with stretch handles, so we have only one. */