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      1 // Copyright (c) 2011 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 "chrome/browser/ui/gtk/gconf_titlebar_listener.h"
      6 
      7 #include <gtk/gtk.h>
      8 
      9 #include "base/environment.h"
     10 #include "base/memory/scoped_ptr.h"
     11 #include "base/memory/singleton.h"
     12 #include "base/nix/xdg_util.h"
     13 #include "chrome/browser/ui/gtk/browser_titlebar.h"
     14 
     15 namespace {
     16 
     17 // The GConf key we read for the button placement string. Even through the key
     18 // has "metacity" in it, it's shared between metacity and compiz.
     19 const char* kButtonLayoutKey = "/apps/metacity/general/button_layout";
     20 
     21 // GConf requires us to subscribe to a parent directory before we can subscribe
     22 // to changes in an individual key in that directory.
     23 const char* kMetacityGeneral = "/apps/metacity/general";
     24 
     25 }  // namespace
     26 
     27 // Public interface:
     28 
     29 // static
     30 GConfTitlebarListener* GConfTitlebarListener::GetInstance() {
     31   return Singleton<GConfTitlebarListener>::get();
     32 }
     33 
     34 void GConfTitlebarListener::SetTitlebarButtons(BrowserTitlebar* titlebar) {
     35   if (client_) {
     36     titlebar->BuildButtons(current_value_);
     37     titlebars_.insert(titlebar);
     38   } else {
     39     titlebar->BuildButtons(BrowserTitlebar::kDefaultButtonString);
     40   }
     41 }
     42 
     43 void GConfTitlebarListener::RemoveObserver(BrowserTitlebar* titlebar) {
     44   titlebars_.erase(titlebar);
     45 }
     46 
     47 // Protected:
     48 
     49 GConfTitlebarListener::~GConfTitlebarListener() {}
     50 
     51 // Private:
     52 
     53 GConfTitlebarListener::GConfTitlebarListener() : client_(NULL) {
     54   scoped_ptr<base::Environment> env(base::Environment::Create());
     55   if (base::nix::GetDesktopEnvironment(env.get()) ==
     56       base::nix::DESKTOP_ENVIRONMENT_GNOME) {
     57     client_ = gconf_client_get_default();
     58     // If we fail to get a context, that's OK, since we'll just fallback on
     59     // not receiving gconf keys.
     60     if (client_) {
     61       // Get the initial value of the key.
     62       GError* error = NULL;
     63       GConfValue* gconf_value = gconf_client_get(client_, kButtonLayoutKey,
     64                                                  &error);
     65       if (HandleGError(error, kButtonLayoutKey))
     66         return;
     67       ParseAndStoreValue(gconf_value);
     68       if (gconf_value)
     69         gconf_value_free(gconf_value);
     70 
     71       // Register that we're interested in the values of this directory.
     72       gconf_client_add_dir(client_, kMetacityGeneral,
     73                            GCONF_CLIENT_PRELOAD_ONELEVEL, &error);
     74       if (HandleGError(error, kMetacityGeneral))
     75         return;
     76 
     77       // Register to get notifies about changes to this key.
     78       gconf_client_notify_add(
     79           client_, kButtonLayoutKey,
     80           reinterpret_cast<void (*)(GConfClient*, guint, GConfEntry*, void*)>(
     81               OnChangeNotificationThunk),
     82           this, NULL, &error);
     83       if (HandleGError(error, kButtonLayoutKey))
     84         return;
     85     }
     86   }
     87 }
     88 
     89 void GConfTitlebarListener::OnChangeNotification(GConfClient* client,
     90                                                  guint cnxn_id,
     91                                                  GConfEntry* entry) {
     92   if (strcmp(gconf_entry_get_key(entry), kButtonLayoutKey) == 0) {
     93     GConfValue* gconf_value = gconf_entry_get_value(entry);
     94     ParseAndStoreValue(gconf_value);
     95 
     96     // Broadcast the new configuration to all windows:
     97     for (std::set<BrowserTitlebar*>::const_iterator it = titlebars_.begin();
     98          it != titlebars_.end(); ++it) {
     99       (*it)->BuildButtons(current_value_);
    100     }
    101   }
    102 }
    103 
    104 bool GConfTitlebarListener::HandleGError(GError* error, const char* key) {
    105   if (error != NULL) {
    106     LOG(ERROR) << "Error with gconf key '" << key << "': " << error->message;
    107     g_error_free(error);
    108     g_object_unref(client_);
    109     client_ = NULL;
    110     return true;
    111   }
    112   return false;
    113 }
    114 
    115 void GConfTitlebarListener::ParseAndStoreValue(GConfValue* gconf_value) {
    116   if (gconf_value) {
    117     const char* value = gconf_value_get_string(gconf_value);
    118     current_value_ = value ? value : BrowserTitlebar::kDefaultButtonString;
    119   } else {
    120     current_value_ = BrowserTitlebar::kDefaultButtonString;
    121   }
    122 }
    123