content/common/notification_service.cc

   1 // Copyright (c) 2010 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 "content/common/notification_service.h"
   6
   7 #include "base/lazy_instance.h"
   8 #include "base/threading/thread_local.h"
   9 #include "content/common/notification_observer.h"
  10
  11 static base::LazyInstance<base::ThreadLocalPointer<NotificationService> >
  12     lazy_tls_ptr(base::LINKER_INITIALIZED);
  13
  14 // static
  15 NotificationService* NotificationService::current() {
  16   return lazy_tls_ptr.Pointer()->Get();
  17 }
  18
  19 // static
  20 bool NotificationService::HasKey(const NotificationSourceMap& map,
  21                                  const NotificationSource& source) {
  22   return map.find(source.map_key()) != map.end();
  23 }
  24
  25 NotificationService::NotificationService() {
  26   DCHECK(current() == NULL);
  27   lazy_tls_ptr.Pointer()->Set(this);
  28 }
  29
  30 void NotificationService::AddObserver(NotificationObserver* observer,
  31                                       int type,
  32                                       const NotificationSource& source) {
  33   // We have gotten some crashes where the observer pointer is NULL. The problem
  34   // is that this happens when we actually execute a notification, so have no
  35   // way of knowing who the bad observer was. We want to know when this happens
  36   // in release mode so we know what code to blame the crash on (since this is
  37   // guaranteed to crash later).
  38   CHECK(observer);
  39
  40   NotificationObserverList* observer_list;
  41   if (HasKey(observers_[type], source)) {
  42     observer_list = observers_[type][source.map_key()];
  43   } else {
  44     observer_list = new NotificationObserverList;
  45     observers_[type][source.map_key()] = observer_list;
  46   }
  47
  48   observer_list->AddObserver(observer);
  49 #ifndef NDEBUG
  50   ++observer_counts_[type];
  51 #endif
  52 }
  53
  54 void NotificationService::RemoveObserver(NotificationObserver* observer,
  55                                          int type,
  56                                          const NotificationSource& source) {
  57   // This is a very serious bug.  An object is most likely being deleted on
  58   // the wrong thread, and as a result another thread's NotificationService
  59   // has its deleted pointer in its map.  A garbge object will be called in the
  60   // future.
  61   // NOTE: when this check shows crashes, use BrowserThread::DeleteOnIOThread or
  62   // other variants as the trait on the object.
  63   CHECK(HasKey(observers_[type], source));
  64
  65   NotificationObserverList* observer_list =
  66       observers_[type][source.map_key()];
  67   if (observer_list) {
  68     observer_list->RemoveObserver(observer);
  69 #ifndef NDEBUG
  70     --observer_counts_[type];
  71 #endif
  72   }
  73
  74   // TODO(jhughes): Remove observer list from map if empty?
  75 }
  76
  77 void NotificationService::Notify(int type,
  78                                  const NotificationSource& source,
  79                                  const NotificationDetails& details) {
  80   DCHECK(type > content::NOTIFICATION_ALL) <<
  81       "Allowed for observing, but not posting.";
  82
  83   // There's no particular reason for the order in which the different
  84   // classes of observers get notified here.
  85
  86   // Notify observers of all types and all sources
  87   if (HasKey(observers_[content::NOTIFICATION_ALL], AllSources()) &&
  88       source != AllSources()) {
  89     FOR_EACH_OBSERVER(NotificationObserver,
  90        *observers_[content::NOTIFICATION_ALL][AllSources().map_key()],
  91        Observe(type, source, details));
  92   }
  93
  94   // Notify observers of all types and the given source
  95   if (HasKey(observers_[content::NOTIFICATION_ALL], source)) {
  96     FOR_EACH_OBSERVER(NotificationObserver,
  97         *observers_[content::NOTIFICATION_ALL][source.map_key()],
  98         Observe(type, source, details));
  99   }
 100
 101   // Notify observers of the given type and all sources
 102   if (HasKey(observers_[type], AllSources()) &&
 103       source != AllSources()) {
 104     FOR_EACH_OBSERVER(NotificationObserver,
 105                       *observers_[type][AllSources().map_key()],
 106                       Observe(type, source, details));
 107   }
 108
 109   // Notify observers of the given type and the given source
 110   if (HasKey(observers_[type], source)) {
 111     FOR_EACH_OBSERVER(NotificationObserver,
 112                       *observers_[type][source.map_key()],
 113                       Observe(type, source, details));
 114   }
 115 }
 116
 117
 118 NotificationService::~NotificationService() {
 119   lazy_tls_ptr.Pointer()->Set(NULL);
 120
 121 #ifndef NDEBUG
 122   for (int i = 0; i < static_cast<int>(observer_counts_.size()); i++) {
 123     if (observer_counts_[i] > 0) {
 124       // This may not be completely fixable -- see
 125       // http://code.google.com/p/chromium/issues/detail?id=11010 .
 126       VLOG(1) << observer_counts_[i] << " notification observer(s) leaked "
 127                  "of notification type " << i;
 128     }
 129   }
 130 #endif
 131
 132   for (int i = 0; i < static_cast<int>(observers_.size()); i++) {
 133     NotificationSourceMap omap = observers_[i];
 134     for (NotificationSourceMap::iterator it = omap.begin();
 135          it != omap.end(); ++it)
 136       delete it->second;
 137   }
 138 }
 139
 140 NotificationObserver::NotificationObserver() {}
 141
 142 NotificationObserver::~NotificationObserver() {}