This document is deprecated by the new plugin module in globalmenu-plugin/

No design document is yet written for the new plugin module.

Introduction

libglobalmenu-gnome is a GTK plugin module that dynamically patches GTK to make it Global Menu compatible. It overrides several virtual functions, and register several signal handlers and emission hooks in a GTK-opaque way to achieve the following goals: * Serializing the GTK menu hierarchy to the XML reprensentation of Global Menu and set to the Menu Context. * Notifying the application about the arrival of any Menu Event

In short, it makes the idea of Global Menu possible in this complicated real world.

DynPatch

DynPatch library contains the routines to change the behavior of GTK.

Libary Interface

• dyn_patch_init to initalized dyn_patch. The code should be protected by gdk threads lock. (Related to Gnome BUG 566678)
• dyn_patch_uninit to uniniailize dyn_patch. The code should be protected by gdk threads lock, too.

DynPatch exposes three extra signals on a regular GTKMenuBar: * dyn-patch-attached: emitted when the menubar is attached to a toplevel window. The parameter is the toplevel window. * dyn-patch-detached: emitted when the menubar is detached from a toplevel window. The parameter is the old toplevel window. * dyn-patch-changed: emitted when the menu hierarchy leaded by the menubar has changed.

DynPatch exposes two helper functions: * dyn_patch_get_menubar: get the menubar of a given toplevel window. * dyn_patch_get_window: get the toplevel window of a given menubar.

Under the Stage

Overriding the Virtual Functions

The virtual functions are overriden by brute force, with these macros: OVERRIDE_SAVE, OVERRIDE the old vfuncs are saved in a hash table, to be restored with RESTORE macro.

The overriding is issued by dyn_patch_type on a given type with the patcher function. The patcher functions are given in dyn-patch-menubar.c dyn-patch-widget.c dyn-patch-menushell.c repectively.

Propagation of the 'menubar' Data Member

If a widget is a direct or indirect child of a menubar, its __dyn-patch-menubar__ data memeber is set to the menubar for later reference.

This done by dyn_patch_set_menubar_r, the parent_set vfunc in dyn-patch-widget.c, and the signal handler on notify::submenu.

Capture Changes: Signal Handlers

The notify signal on relavent widget properties are listened with dyn_patch_simple_notify during the propagation of menubar data memeber.

Buffer the Changes

Not each change in the menu hierarchy emits a dyn-patch-changed signal. Multiple(hundreds) of changes are queued with a g_idle_add_full, and then emitted in one run.

Global Menu

About globalmenu.vala.

Signal Emission Hooks

It listens to the signals defined by DynPatch, and the property-notify event on toplevel windows for Global Menu events.

Serializer

Convert the widget tree to xml.

Locator

Convert an xpath to a widget.