[gnome-photos] preview-nav-buttons: Restrict keynav within the bounds of the model

[Debarshi Ray <debarshir src gnome org>]

commit e8a445ee37c3ff53b82b1eb557afdbebdb8ea6b1
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Jul 18 12:55:11 2014 +0200

    preview-nav-buttons: Restrict keynav within the bounds of the model
    
    We hide the buttons when after reaching one end of the model. We
    should also disable keyboard navigation in such cases.
    
    Fallout from edc439c92044b04395e88391d8379f4911eb65bc
    
    Fixes: https://bugzilla.gnome.org/726685

 src/photos-preview-nav-buttons.c |  112 ++++++++++++++++++++++++++++++++++----
 1 files changed, 101 insertions(+), 11 deletions(-)
---
diff --git a/src/photos-preview-nav-buttons.c b/src/photos-preview-nav-buttons.c
index 4c195ab..fabf559 100644
--- a/src/photos-preview-nav-buttons.c
+++ b/src/photos-preview-nav-buttons.c
@@ -49,6 +49,8 @@ struct _PhotosPreviewNavButtonsPrivate
   GtkWidget *toolbar_widget;
   PhotosBaseManager *item_mngr;
   PhotosPreviewAction action;
+  gboolean enable_next;
+  gboolean enable_prev;
   gboolean hover;
   gboolean visible;
   guint auto_hide_id;
@@ -58,6 +60,8 @@ struct _PhotosPreviewNavButtonsPrivate
 enum
 {
   PROP_0,
+  PROP_ENABLE_NEXT,
+  PROP_ENABLE_PREVIOUS,
   PROP_OVERLAY,
   PROP_PREVIEW_VIEW
 };
@@ -237,34 +241,33 @@ photos_preview_nav_buttons_update_visibility (PhotosPreviewNavButtons *self)
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
   GtkTreeIter iter;
   GtkTreeIter tmp;
+  gboolean enable_next = FALSE;
+  gboolean enable_prev = FALSE;
 
   if (priv->model == NULL
       || priv->current_path == NULL
       || !priv->visible
       || !gtk_tree_model_get_iter (priv->model, &iter, priv->current_path))
     {
-      photos_preview_nav_buttons_fade_out_button (self, priv->prev_widget);
-      photos_preview_nav_buttons_fade_out_button (self, priv->next_widget);
+      enable_prev = FALSE;
+      enable_next = FALSE;
       photos_preview_nav_buttons_fade_out_button (self, priv->toolbar_widget);
-      return;
+      goto out;
     }
 
   photos_preview_nav_buttons_fade_in_button (self, priv->toolbar_widget);
 
   tmp = iter;
-  if (gtk_tree_model_iter_previous (priv->model, &tmp))
-      photos_preview_nav_buttons_fade_in_button (self, priv->prev_widget);
-  else
-      photos_preview_nav_buttons_fade_out_button (self, priv->prev_widget);
+  enable_prev = gtk_tree_model_iter_previous (priv->model, &tmp);
 
   tmp = iter;
-  if (gtk_tree_model_iter_next (priv->model, &tmp))
-      photos_preview_nav_buttons_fade_in_button (self, priv->next_widget);
-  else
-      photos_preview_nav_buttons_fade_out_button (self, priv->next_widget);
+  enable_next = gtk_tree_model_iter_next (priv->model, &tmp);
 
   if (!priv->hover)
     photos_preview_nav_buttons_queue_auto_hide (self);
+
+ out:
+  g_object_set (self, "enable-next", enable_next, "enable-previous", enable_prev, NULL);
 }
 
 
@@ -294,6 +297,30 @@ photos_preview_nav_buttons_motion_notify (PhotosPreviewNavButtons *self)
 
 
 static void
+photos_preview_nav_buttons_notify_enable_next (PhotosPreviewNavButtons *self)
+{
+  PhotosPreviewNavButtonsPrivate *priv = self->priv;
+
+  if (priv->enable_next)
+    photos_preview_nav_buttons_fade_in_button (self, priv->next_widget);
+  else
+    photos_preview_nav_buttons_fade_out_button (self, priv->next_widget);
+}
+
+
+static void
+photos_preview_nav_buttons_notify_enable_previous (PhotosPreviewNavButtons *self)
+{
+  PhotosPreviewNavButtonsPrivate *priv = self->priv;
+
+  if (priv->enable_prev)
+    photos_preview_nav_buttons_fade_in_button (self, priv->prev_widget);
+  else
+    photos_preview_nav_buttons_fade_out_button (self, priv->prev_widget);
+}
+
+
+static void
 photos_preview_nav_buttons_set_active_path (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
@@ -448,6 +475,29 @@ photos_preview_nav_buttons_constructed (GObject *object)
 
 
 static void
+photos_preview_nav_buttons_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
+{
+  PhotosPreviewNavButtons *self = PHOTOS_PREVIEW_NAV_BUTTONS (object);
+  PhotosPreviewNavButtonsPrivate *priv = self->priv;
+
+  switch (prop_id)
+    {
+    case PROP_ENABLE_NEXT:
+      g_value_set_boolean (value, priv->enable_next);
+      break;
+
+    case PROP_ENABLE_PREVIOUS:
+      g_value_set_boolean (value, priv->enable_prev);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+
+static void
 photos_preview_nav_buttons_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec 
*pspec)
 {
   PhotosPreviewNavButtons *self = PHOTOS_PREVIEW_NAV_BUTTONS (object);
@@ -455,6 +505,14 @@ photos_preview_nav_buttons_set_property (GObject *object, guint prop_id, const G
 
   switch (prop_id)
     {
+    case PROP_ENABLE_NEXT:
+      priv->enable_next = g_value_get_boolean (value);
+      break;
+
+    case PROP_ENABLE_PREVIOUS:
+      priv->enable_prev = g_value_get_boolean (value);
+      break;
+
     case PROP_OVERLAY:
       priv->overlay = GTK_WIDGET (g_value_dup_object (value));
       break;
@@ -485,6 +543,15 @@ photos_preview_nav_buttons_init (PhotosPreviewNavButtons *self)
                             self);
 
   priv->action = PHOTOS_PREVIEW_ACTION_NONE;
+
+  g_signal_connect (self,
+                    "notify::enable-next",
+                    G_CALLBACK (photos_preview_nav_buttons_notify_enable_next),
+                    NULL);
+  g_signal_connect (self,
+                    "notify::enable-previous",
+                    G_CALLBACK (photos_preview_nav_buttons_notify_enable_previous),
+                    NULL);
 }
 
 
@@ -496,9 +563,26 @@ photos_preview_nav_buttons_class_init (PhotosPreviewNavButtonsClass *class)
   object_class->constructed = photos_preview_nav_buttons_constructed;
   object_class->dispose = photos_preview_nav_buttons_dispose;
   object_class->finalize = photos_preview_nav_buttons_finalize;
+  object_class->get_property = photos_preview_nav_buttons_get_property;
   object_class->set_property = photos_preview_nav_buttons_set_property;
 
   g_object_class_install_property (object_class,
+                                   PROP_ENABLE_NEXT,
+                                   g_param_spec_boolean ("enable-next",
+                                                         "Enable next",
+                                                         "Allow moving to the next item",
+                                                         FALSE,
+                                                         G_PARAM_READWRITE));
+
+  g_object_class_install_property (object_class,
+                                   PROP_ENABLE_PREVIOUS,
+                                   g_param_spec_boolean ("enable-previous",
+                                                         "Enable previous",
+                                                         "Allow moving to the previous item",
+                                                         FALSE,
+                                                         G_PARAM_READWRITE));
+
+  g_object_class_install_property (object_class,
                                    PROP_OVERLAY,
                                    g_param_spec_object ("overlay",
                                                         "GtkOverlay object",
@@ -561,6 +645,9 @@ photos_preview_nav_buttons_next (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
 
+  if (!priv->enable_next)
+    return;
+
   priv->action = PHOTOS_PREVIEW_ACTION_NEXT;
   gtk_tree_path_next (priv->current_path);
   photos_preview_nav_buttons_set_active_path (self);
@@ -574,6 +661,9 @@ photos_preview_nav_buttons_previous (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
 
+  if (!priv->enable_prev)
+    return;
+
   priv->action = PHOTOS_PREVIEW_ACTION_PREVIOUS;
   gtk_tree_path_prev (priv->current_path);
   photos_preview_nav_buttons_set_active_path (self);