keyboard: bring back uniqueness check

The collision detection code was removed in commit a0a155884e
as the cleanup was happening because the previous code was closely
tied to the user interface components.

Because that code wasn't appliable to the new listbox UI, it was
temporarily removed.

This patch re-adds this feature to work with the new code orgazination.

https://bugzilla.gnome.org/show_bug.cgi?id=769063

panels/keyboard/cc-keyboard-manager.c

@@ -84,6 +84,62 @@ free_key_array (GPtrArray *keys)
     }
 }
 
+static gboolean
+compare_keys_for_uniqueness (CcKeyboardItem   *current_item,
+                             CcUniquenessData *data)
+{
+  CcKeyboardItem *item;
+
+  item = data->orig_item;
+
+  /* No conflict for: blanks, different modifiers or ourselves */
+  if (!current_item ||
+      item == current_item ||
+      data->new_mask != current_item->mask)
+    {
+      return FALSE;
+    }
+
+  if (item && cc_keyboard_item_equal (item, current_item))
+    goto out;
+
+  if (data->new_keyval != 0)
+    {
+      if (data->new_keyval != current_item->keyval)
+          return FALSE;
+    }
+  else if (current_item->keyval != 0 || data->new_keycode != current_item->keycode)
+    {
+      return FALSE;
+    }
+
+out:
+  data->conflict_item = current_item;
+
+  return TRUE;
+}
+
+static gboolean
+check_for_uniqueness (gpointer          key,
+                      GPtrArray        *keys_array,
+                      CcUniquenessData *data)
+{
+  guint i;
+
+  for (i = 0; i < keys_array->len; i++)
+    {
+      CcKeyboardItem *item;
+
+      item = keys_array->pdata[i];
+
+      if (compare_keys_for_uniqueness (item, data))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
+
 static GHashTable*
 get_hash_for_group (CcKeyboardManager *self,
                     BindingGroupType   group)
@@ -815,3 +871,69 @@ cc_keyboard_manager_remove_custom_shortcut  (CcKeyboardManager *self,
 
   g_signal_emit (self, signals[SHORTCUT_REMOVED], 0, item);
 }
+
+/**
+ * cc_keyboard_manager_get_collision:
+ * @self: a #CcKeyboardManager
+ * @item: (nullable): a keyboard shortcut
+ * @keyval: the key value
+ * @mask: a mask for the key sequence
+ * @keycode: the code of the key.
+ *
+ * Retrieves the collision item for the given shortcut.
+ *
+ * Returns: (transfer none)(nullable): the collisioned shortcut
+ */
+CcKeyboardItem*
+cc_keyboard_manager_get_collision (CcKeyboardManager *self,
+                                   CcKeyboardItem    *item,
+                                   gint               keyval,
+                                   GdkModifierType    mask,
+                                   gint               keycode)
+{
+  CcUniquenessData data;
+
+  g_return_val_if_fail (CC_IS_KEYBOARD_MANAGER (self), NULL);
+
+  data.orig_item = item;
+  data.new_keyval = keyval;
+  data.new_mask = mask;
+  data.new_keycode = keycode;
+  data.conflict_item = NULL;
+
+  /* Any number of shortcuts can be disabled */
+  if (keyval != 0 || keycode != 0)
+    {
+      BindingGroupType i;
+
+      for (i = BINDING_GROUP_SYSTEM; i <= BINDING_GROUP_USER && !data.conflict_item; i++)
+        {
+          GHashTable *table;
+
+          table = get_hash_for_group (self, i);
+
+          if (!table)
+            continue;
+
+          g_hash_table_find (table, (GHRFunc) check_for_uniqueness, &data);
+        }
+    }
+
+  return data.conflict_item;
+}
+
+/**
+ * cc_keyboard_manager_disable_shortcut:
+ * @self: a #CcKeyboardManager
+ * @item: a @CcKeyboardItem
+ *
+ * Disables the given keyboard shortcut.
+ */
+void
+cc_keyboard_manager_disable_shortcut (CcKeyboardManager *self,
+                                      CcKeyboardItem    *item)
+{
+  g_return_if_fail (CC_IS_KEYBOARD_MANAGER (self));
+
+  g_object_set (item, "binding", NULL, NULL);
+}

panels/keyboard/cc-keyboard-manager.h

@@ -45,6 +45,15 @@ void                 cc_keyboard_manager_add_custom_shortcut     (CcKeyboardMana
 void                 cc_keyboard_manager_remove_custom_shortcut  (CcKeyboardManager  *self,
                                                                   CcKeyboardItem     *item);
 
+CcKeyboardItem*      cc_keyboard_manager_get_collision           (CcKeyboardManager  *self,
+                                                                  CcKeyboardItem     *item,
+                                                                  gint                keyval,
+                                                                  GdkModifierType     mask,
+                                                                  gint                keycode);
+
+void                 cc_keyboard_manager_disable_shortcut        (CcKeyboardManager  *self,
+                                                                  CcKeyboardItem     *item);
+
 G_END_DECLS
 
 #endif /* CC_KEYBOARD_MANAGER_H */

panels/keyboard/cc-keyboard-shortcut-editor.c

@@ -40,9 +40,11 @@ struct _CcKeyboardShortcutEditor
   GtkWidget          *edit_button;
   GtkWidget          *headerbar;
   GtkWidget          *name_entry;
+  GtkWidget          *new_shortcut_conflict_label;
   GtkWidget          *remove_button;
   GtkWidget          *replace_button;
   GtkWidget          *shortcut_accel_label;
+  GtkWidget          *shortcut_conflict_label;
   GtkWidget          *stack;
   GtkWidget          *top_info_label;
 
@@ -53,6 +55,8 @@ struct _CcKeyboardShortcutEditor
   CcKeyboardManager  *manager;
   CcKeyboardItem     *item;
 
+  CcKeyboardItem     *collision_item;
+
   /* Custom shortcuts */
   GdkDevice          *grab_pointer;
 
@@ -122,6 +126,8 @@ clear_custom_entries (CcKeyboardShortcutEditor *self)
   gtk_entry_set_text (GTK_ENTRY (self->command_entry), "");
 
   gtk_shortcut_label_set_accelerator (GTK_SHORTCUT_LABEL (self->custom_shortcut_accel_label), "");
+  gtk_label_set_label (GTK_LABEL (self->new_shortcut_conflict_label), "");
+  gtk_label_set_label (GTK_LABEL (self->shortcut_conflict_label), "");
 
   self->custom_keycode = 0;
   self->custom_keyval = 0;
@@ -129,6 +135,8 @@ clear_custom_entries (CcKeyboardShortcutEditor *self)
   self->custom_is_modifier = TRUE;
   self->edited = FALSE;
 
+  self->collision_item = NULL;
+
   g_signal_handlers_unblock_by_func (self->command_entry, command_entry_changed_cb, self);
   g_signal_handlers_unblock_by_func (self->name_entry, name_entry_changed_cb, self);
 }
@@ -200,6 +208,10 @@ update_shortcut (CcKeyboardShortcutEditor *self)
   /* Setup the binding */
   apply_custom_item_fields (self, self->item);
 
+  /* Eventually disable the conflict shortcut */
+  if (self->collision_item)
+    cc_keyboard_manager_disable_shortcut (self->manager, self->collision_item);
+
   /* Cleanup whatever was set before */
   clear_custom_entries (self);
 
@@ -215,10 +227,21 @@ get_current_shortcut_label (CcKeyboardShortcutEditor *self)
   return GTK_SHORTCUT_LABEL (self->shortcut_accel_label);
 }
 
+static void
+set_collision_headerbar (CcKeyboardShortcutEditor *self,
+                         gboolean                  has_collision)
+{
+  gtk_header_bar_set_show_close_button (GTK_HEADER_BAR (self->headerbar), !has_collision);
+
+  gtk_widget_set_visible (self->cancel_button, has_collision);
+  gtk_widget_set_visible (self->replace_button, has_collision);
+}
+
 static void
 setup_custom_shortcut (CcKeyboardShortcutEditor *self)
 {
   GtkShortcutLabel *shortcut_label;
+  CcKeyboardItem *collision_item;
   gboolean valid;
   gchar *accel;
 
@@ -240,8 +263,16 @@ setup_custom_shortcut (CcKeyboardShortcutEditor *self)
     return;
 
   shortcut_label = get_current_shortcut_label (self);
+
+  collision_item = cc_keyboard_manager_get_collision (self->manager,
+                                                      self->item,
+                                                      self->custom_keyval,
+                                                      self->custom_mask,
+                                                      self->custom_keycode);
+
   accel = gtk_accelerator_name (self->custom_keyval, self->custom_mask);
 
+
   /* Setup the accelerator label */
   gtk_shortcut_label_set_accelerator (shortcut_label, accel);
 
@@ -255,6 +286,48 @@ setup_custom_shortcut (CcKeyboardShortcutEditor *self)
 
   release_grab (self);
 
+  /*
+   * Oops! Looks like the accelerator is already being used, so we
+   * must warn the user and let it be very clear that adding this
+   * shortcut will disable the other.
+   */
+  gtk_widget_set_visible (self->new_shortcut_conflict_label, collision_item != NULL);
+
+  if (collision_item)
+    {
+      GtkWidget *label;
+      gchar *friendly_accelerator;
+      gchar *collision_text;
+
+      friendly_accelerator = convert_keysym_state_to_string (self->custom_keyval,
+                                                             self->custom_mask,
+                                                             self->custom_keycode);
+
+      collision_text = g_strdup_printf (_("%s is already being used for <b>%s</b>. If you "
+                                          "replace it, %s will be disabled"),
+                                        friendly_accelerator,
+                                        collision_item->description,
+                                        collision_item->description);
+
+      label = is_custom_shortcut (self) ? self->new_shortcut_conflict_label : self->shortcut_conflict_label;
+
+      gtk_label_set_markup (GTK_LABEL (label), collision_text);
+
+      g_free (friendly_accelerator);
+      g_free (collision_text);
+    }
+
+  /*
+   * When there is a collision between the current shortcut and another shortcut,
+   * and we're editing an existing shortcut (rather than creating a new one), setup
+   * the headerbar to display "Cancel" and "Replace". Otherwise, make sure to set
+   * only the close button again.
+   */
+  if (self->mode == CC_SHORTCUT_EDITOR_EDIT)
+    set_collision_headerbar (self, collision_item != NULL);
+
+  self->collision_item = collision_item;
+
   g_free (accel);
 }
 
@@ -268,6 +341,10 @@ add_button_clicked_cb (CcKeyboardShortcutEditor *self)
   /* Apply the custom shortcut setup at the new item */
   apply_custom_item_fields (self, item);
 
+  /* Eventually disable the conflict shortcut */
+  if (self->collision_item)
+    cc_keyboard_manager_disable_shortcut (self->manager, self->collision_item);
+
   /* Cleanup everything once we're done */
   clear_custom_entries (self);
 
@@ -317,6 +394,14 @@ remove_button_clicked_cb (CcKeyboardShortcutEditor *self)
   cc_keyboard_manager_remove_custom_shortcut (self->manager, self->item);
 }
 
+static void
+replace_button_clicked_cb (CcKeyboardShortcutEditor *self)
+{
+  update_shortcut (self);
+
+  gtk_widget_hide (GTK_WIDGET (self));
+}
+
 static void
 setup_keyboard_item (CcKeyboardShortcutEditor *self,
                      CcKeyboardItem           *item)
@@ -572,9 +657,11 @@ cc_keyboard_shortcut_editor_class_init (CcKeyboardShortcutEditorClass *klass)
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, edit_button);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, headerbar);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, name_entry);
+  gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, new_shortcut_conflict_label);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, remove_button);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, replace_button);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, shortcut_accel_label);
+  gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, shortcut_conflict_label);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, stack);
   gtk_widget_class_bind_template_child (widget_class, CcKeyboardShortcutEditor, top_info_label);
 
@@ -584,6 +671,7 @@ cc_keyboard_shortcut_editor_class_init (CcKeyboardShortcutEditorClass *klass)
   gtk_widget_class_bind_template_callback (widget_class, edit_custom_shortcut_button_toggled_cb);
   gtk_widget_class_bind_template_callback (widget_class, name_entry_changed_cb);
   gtk_widget_class_bind_template_callback (widget_class, remove_button_clicked_cb);
+  gtk_widget_class_bind_template_callback (widget_class, replace_button_clicked_cb);
 }
 
 static void
@@ -660,12 +748,17 @@ void
 cc_keyboard_shortcut_editor_set_mode (CcKeyboardShortcutEditor *self,
                                       CcShortcutEditorMode      mode)
 {
+  gboolean is_create_mode;
+
   g_return_if_fail (CC_IS_KEYBOARD_SHORTCUT_EDITOR (self));
 
   if (self->mode == mode)
     return;
 
   self->mode = mode;
+  is_create_mode = mode == CC_SHORTCUT_EDITOR_CREATE;
+
+  gtk_widget_set_visible (self->new_shortcut_conflict_label, is_create_mode);
 
   if (mode == CC_SHORTCUT_EDITOR_CREATE)
     {

panels/keyboard/shortcut-editor.ui

@@ -45,6 +45,18 @@
                     <property name="disabled-text" translatable="yes">Disabled</property>
                   </object>
                 </child>
+                <child>
+                  <object class="GtkLabel" id="shortcut_conflict_label">
+                    <property name="visible">True</property>
+                    <property name="can_focus">False</property>
+                    <property name="hexpand">True</property>
+                    <property name="wrap">True</property>
+                    <property name="wrap_mode">word-char</property>
+                    <property name="width_chars">15</property>
+                    <property name="max_width_chars">20</property>
+                    <property name="xalign">0</property>
+                  </object>
+                </child>
                 <child>
                   <object class="GtkButton" id="reset_button">
                     <property name="label" translatable="yes">Reset</property>
@@ -242,6 +254,7 @@
             <property name="visible">True</property>
             <property name="can_focus">True</property>
             <property name="receives_default">True</property>
+            <signal name="clicked" handler="replace_button_clicked_cb" object="CcKeyboardShortcutEditor" swapped="yes" />
           </object>
           <packing>
             <property name="pack_type">end</property>