src/ui/base/x/active_window_watcher_x.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/base/x/active_window_watcher_x.h"
   6
   7 #include <gdk/gdk.h>
   8 #include <gdk/gdkx.h>
   9
  10 #include "base/memory/singleton.h"
  11 #include "ui/base/x/active_window_watcher_x_observer.h"
  12 #include "ui/base/x/root_window_property_watcher_x.h"
  13 #include "ui/base/x/x11_util.h"
  14 #include "ui/gfx/gdk_compat.h"
  15 #include "ui/gfx/gtk_compat.h"
  16
  17 namespace ui {
  18
  19 static const char* const kNetActiveWindow = "_NET_ACTIVE_WINDOW";
  20
  21 // static
  22 ActiveWindowWatcherX* ActiveWindowWatcherX::GetInstance() {
  23   return Singleton<ActiveWindowWatcherX>::get();
  24 }
  25
  26 // static
  27 void ActiveWindowWatcherX::AddObserver(ActiveWindowWatcherXObserver* observer) {
  28   // Ensure that RootWindowPropertyWatcherX exists.
  29   internal::RootWindowPropertyWatcherX::GetInstance();
  30   GetInstance()->observers_.AddObserver(observer);
  31 }
  32
  33 // static
  34 void ActiveWindowWatcherX::RemoveObserver(
  35     ActiveWindowWatcherXObserver* observer) {
  36   GetInstance()->observers_.RemoveObserver(observer);
  37 }
  38
  39 // static
  40 Atom ActiveWindowWatcherX::GetPropertyAtom() {
  41   return GetAtom(kNetActiveWindow);
  42 }
  43
  44 // static
  45 void ActiveWindowWatcherX::Notify() {
  46   GetInstance()->NotifyActiveWindowChanged();
  47 }
  48
  49 // static
  50 bool ActiveWindowWatcherX::WMSupportsActivation() {
  51   return gdk_x11_screen_supports_net_wm_hint(
  52       gdk_screen_get_default(),
  53       gdk_atom_intern_static_string(kNetActiveWindow));
  54 }
  55
  56 ActiveWindowWatcherX::ActiveWindowWatcherX() {
  57 }
  58
  59 ActiveWindowWatcherX::~ActiveWindowWatcherX() {
  60 }
  61
  62 void ActiveWindowWatcherX::NotifyActiveWindowChanged() {
  63   // We don't use gdk_screen_get_active_window() because it caches
  64   // whether or not the window manager supports _NET_ACTIVE_WINDOW.
  65   // This causes problems at startup for chromiumos.
  66   Atom type = None;
  67   int format = 0;  // size in bits of each item in 'property'
  68   long unsigned int num_items = 0, remaining_bytes = 0;
  69   unsigned char* property = NULL;
  70
  71   XGetWindowProperty(gdk_x11_get_default_xdisplay(),
  72                      GDK_WINDOW_XID(gdk_get_default_root_window()),
  73                      GetAtom(kNetActiveWindow),
  74                      0,      // offset into property data to read
  75                      1,      // length to get in 32-bit quantities
  76                      False,  // deleted
  77                      AnyPropertyType,
  78                      &type,
  79                      &format,
  80                      &num_items,
  81                      &remaining_bytes,
  82                      &property);
  83
  84   // Check that the property was set and contained a single 32-bit item (we
  85   // don't check that remaining_bytes is 0, though, as XFCE's window manager
  86   // seems to actually store two values in the property for some unknown
  87   // reason.)
  88   if (format == 32 && num_items == 1) {
  89     int xid = *reinterpret_cast<int*>(property);
  90     GdkDisplay* display = gdk_display_get_default();
  91     GdkWindow* active_window = gdk_x11_window_lookup_for_display(display, xid);
  92     FOR_EACH_OBSERVER(ActiveWindowWatcherXObserver, observers_,
  93                       ActiveWindowChanged(active_window));
  94   }
  95   if (property)
  96     XFree(property);
  97 }
  98
  99 }  // namespace ui