_MUTTER_HINTS

A per-window _MUTTER_HINTS property allowing plugins to use custom hints. The
property holds a colon separated list of key=value pairs; plugin-specific keys
must be suitably namespaced, while 'mutter-' prefix is reserved for internal
Mutter use only.

This commit adds MetaWindow::mutter-hints property, and
meta_window_get_mutter_hints() accessor, as well as the internal machinery for
reading and updating of the hints.

https://bugzilla.gnome.org/show_bug.cgi?id=613123

src/core/window-private.h

@@ -96,6 +96,7 @@ struct _MetaWindow
   char *sm_client_id;
   char *wm_client_machine;
   char *startup_id;
+  char *mutter_hints;
 
   int net_wm_pid;
   

src/core/window-props.c

@@ -523,6 +523,49 @@ reload_wm_name (MetaWindow    *window,
     }
 }
 
+static void
+reload_mutter_hints (MetaWindow    *window,
+                     MetaPropValue *value,
+                     gboolean       initial)
+{
+  if (value->type != META_PROP_VALUE_INVALID)
+    {
+      char     *new_hints = value->v.str;
+      char     *old_hints = window->mutter_hints;
+      gboolean  changed   = FALSE;
+
+      if (new_hints)
+        {
+          if (!old_hints || strcmp (new_hints, old_hints))
+            changed = TRUE;
+        }
+      else
+        {
+          if (old_hints)
+            changed = TRUE;
+        }
+
+      if (changed)
+        {
+          g_free (old_hints);
+
+          if (new_hints)
+            window->mutter_hints = g_strdup (new_hints);
+          else
+            window->mutter_hints = NULL;
+
+          g_object_notify (G_OBJECT (window), "mutter-hints");
+        }
+    }
+  else if (window->mutter_hints)
+    {
+      g_free (window->mutter_hints);
+      window->mutter_hints = NULL;
+
+      g_object_notify (G_OBJECT (window), "mutter-hints");
+    }
+}
+
 static void
 set_icon_title (MetaWindow *window,
                 const char *title)
@@ -1506,6 +1549,7 @@ meta_display_init_window_prop_hooks (MetaDisplay *display)
     { XA_WM_CLASS,                     META_PROP_VALUE_CLASS_HINT, reload_wm_class,        TRUE,  TRUE },
     { display->atom__NET_WM_PID,       META_PROP_VALUE_CARDINAL, reload_net_wm_pid,        TRUE,  TRUE },
     { XA_WM_NAME,                      META_PROP_VALUE_TEXT_PROPERTY, reload_wm_name,      TRUE,  TRUE },
+    { display->atom__MUTTER_HINTS,     META_PROP_VALUE_TEXT_PROPERTY, reload_mutter_hints, TRUE,  TRUE },
     { display->atom__NET_WM_ICON_NAME, META_PROP_VALUE_UTF8,     reload_net_wm_icon_name,  TRUE,  FALSE },
     { XA_WM_ICON_NAME,                 META_PROP_VALUE_TEXT_PROPERTY, reload_wm_icon_name, TRUE,  FALSE },
     { display->atom__NET_WM_DESKTOP,   META_PROP_VALUE_CARDINAL, reload_net_wm_desktop,    TRUE,  FALSE },

src/core/window.c

@@ -146,7 +146,8 @@ enum {
   PROP_WINDOW_TYPE,
   PROP_USER_TIME,
   PROP_DEMANDS_ATTENTION,
-  PROP_URGENT
+  PROP_URGENT,
+  PROP_MUTTER_HINTS
 };
 
 enum
@@ -228,6 +229,9 @@ meta_window_get_property(GObject         *object,
     case PROP_URGENT:
       g_value_set_boolean (value, win->wm_hints_urgent);
       break;
+    case PROP_MUTTER_HINTS:
+      g_value_set_string (value, win->mutter_hints);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -348,6 +352,13 @@ meta_window_class_init (MetaWindowClass *klass)
                                                          FALSE,
                                                          G_PARAM_READABLE));
 
+  g_object_class_install_property (object_class,
+                                   PROP_MUTTER_HINTS,
+                                   g_param_spec_string ("mutter-hints",
+                                                        "_MUTTER_HINTS",
+                                                        "Contents of the _MUTTER_HINTS property of this window",
+                                                        NULL,
+                                                        G_PARAM_READABLE));
   window_signals[WORKSPACE_CHANGED] =
     g_signal_new ("workspace-changed",
                   G_TYPE_FROM_CLASS (object_class),
@@ -9120,3 +9131,29 @@ meta_window_is_modal (MetaWindow *window)
 
   return window->wm_state_modal;
 }
+
+/**
+ * meta_window_get_mutter_hints:
+ * @window: a #MetaWindow
+ *
+ * Gets the current value of the _MUTTER_HINTS property.
+ *
+ * The purpose of the hints is to allow fine-tuning of the Window Manager and
+ * Compositor behaviour on per-window basis, and is intended primarily for
+ * hints that are plugin-specific.
+ *
+ * The property is a list of colon-separated key=value pairs. The key names for
+ * any plugin-specific hints must be suitably namespaced to allow for shared
+ * use; 'mutter-' key prefix is reserved for internal use, and must not be used
+ * by plugins.
+ *
+ * Return value: (transfer none): the _MUTTER_HINTS string, or %NULL if no hints
+ * are set.
+ */
+const char *
+meta_window_get_mutter_hints (MetaWindow *window)
+{
+  g_return_val_if_fail (META_IS_WINDOW (window), NULL);
+
+  return window->mutter_hints;
+}

src/include/atomnames.h

@@ -58,6 +58,7 @@ item(_MUTTER_RESTART_MESSAGE)
 item(_MUTTER_RELOAD_THEME_MESSAGE)
 item(_MUTTER_SET_KEYBINDINGS_MESSAGE)
 item(_MUTTER_TOGGLE_VERBOSE)
+item(_MUTTER_HINTS)
 item(_GNOME_WM_KEYBINDINGS)
 item(_GNOME_PANEL_ACTION)
 item(_GNOME_PANEL_ACTION_MAIN_MENU)

src/include/window.h

@@ -141,4 +141,5 @@ guint32     meta_window_get_user_time (MetaWindow *window);
 int         meta_window_get_pid (MetaWindow *window);
 const char *meta_window_get_client_machine (MetaWindow *window);
 gboolean    meta_window_is_modal (MetaWindow *window);
+const char *meta_window_get_mutter_hints (MetaWindow *window);
 #endif