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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <X11/Xlib.h>
#include <gdk/gdk.h>
#include <gdk/gdkx.h>
#include "app/active_window_watcher_x.h"
static Atom kNetActiveWindowAtom = None;
// static
void ActiveWindowWatcherX::AddObserver(Observer* observer) {
Singleton<ActiveWindowWatcherX>::get()->observers_.AddObserver(observer);
}
// static
void ActiveWindowWatcherX::RemoveObserver(Observer* observer) {
Singleton<ActiveWindowWatcherX>::get()->observers_.RemoveObserver(observer);
}
ActiveWindowWatcherX::ActiveWindowWatcherX() {
Init();
}
void ActiveWindowWatcherX::Init() {
GdkAtom kNetActiveWindow = gdk_atom_intern("_NET_ACTIVE_WINDOW", FALSE);
kNetActiveWindowAtom = gdk_x11_atom_to_xatom_for_display(
gdk_screen_get_display(gdk_screen_get_default()), kNetActiveWindow);
GdkWindow* root = gdk_get_default_root_window();
// Set up X Event filter to listen for PropertyChange X events. These events
// tell us when the active window changes.
gdk_window_add_filter(root, &ActiveWindowWatcherX::OnWindowXEvent, this);
XSelectInput(
GDK_WINDOW_XDISPLAY(root), GDK_WINDOW_XID(root), PropertyChangeMask);
}
void ActiveWindowWatcherX::NotifyActiveWindowChanged() {
// We don't use gdk_screen_get_active_window() because it caches
// whether or not the window manager supports _NET_ACTIVE_WINDOW.
// This causes problems at startup for chromiumos.
Atom type = None;
int format = 0; // size in bits of each item in 'property'
long unsigned int num_items = 0, remaining_bytes = 0;
unsigned char* property = NULL;
XGetWindowProperty(gdk_x11_get_default_xdisplay(),
GDK_WINDOW_XID(gdk_get_default_root_window()),
kNetActiveWindowAtom,
0, // offset into property data to read
1, // length to get in 32-bit quantities
False, // deleted
AnyPropertyType,
&type,
&format,
&num_items,
&remaining_bytes,
&property);
// Check that the property was set and contained a single 32-bit item (we
// don't check that remaining_bytes is 0, though, as XFCE's window manager
// seems to actually store two values in the property for some unknown
// reason.)
if (format == 32 && num_items == 1) {
int xid = *reinterpret_cast<int*>(property);
GdkWindow* active_window = gdk_window_lookup(xid);
FOR_EACH_OBSERVER(
Observer,
observers_,
ActiveWindowChanged(active_window));
}
if (property)
XFree(property);
}
GdkFilterReturn ActiveWindowWatcherX::OnWindowXEvent(GdkXEvent* xevent,
GdkEvent* event, gpointer window_watcher) {
ActiveWindowWatcherX* watcher = reinterpret_cast<ActiveWindowWatcherX*>(
window_watcher);
XEvent* xev = static_cast<XEvent*>(xevent);
if (xev->xany.type == PropertyNotify &&
xev->xproperty.atom == kNetActiveWindowAtom) {
watcher->NotifyActiveWindowChanged();
}
return GDK_FILTER_CONTINUE;
}
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