15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_OBSERVER_LIST_THREADSAFE_H_ 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_OBSERVER_LIST_THREADSAFE_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <algorithm> 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <map> 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/basictypes.h" 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/bind.h" 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/location.h" 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/logging.h" 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/ref_counted.h" 16ca12bfac764ba476d6cd062bf1dde12cc64c3f40Ben Murdoch#include "base/message_loop/message_loop.h" 17868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles)#include "base/message_loop/message_loop_proxy.h" 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/observer_list.h" 192a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#include "base/stl_util.h" 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/platform_thread.h" 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/////////////////////////////////////////////////////////////////////////////// 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// OVERVIEW: 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A thread-safe container for a list of observers. 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This is similar to the observer_list (see observer_list.h), but it 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// is more robust for multi-threaded situations. 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The following use cases are supported: 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// * Observers can register for notifications from any thread. 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Callbacks to the observer will occur on the same thread where 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// the observer initially called AddObserver() from. 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// * Any thread may trigger a notification via Notify(). 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// * Observers can remove themselves from the observer list inside 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// of a callback. 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// * If one thread is notifying observers concurrently with an observer 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// removing itself from the observer list, the notifications will 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// be silently dropped. 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The drawback of the threadsafe observer list is that notifications 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// are not as real-time as the non-threadsafe version of this class. 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Notifications will always be done via PostTask() to another thread, 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// whereas with the non-thread-safe observer_list, notifications happen 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// synchronously and immediately. 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// IMPLEMENTATION NOTES 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The ObserverListThreadSafe maintains an ObserverList for each thread 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// which uses the ThreadSafeObserver. When Notifying the observers, 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// we simply call PostTask to each registered thread, and then each thread 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// will notify its regular ObserverList. 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/////////////////////////////////////////////////////////////////////////////// 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Forward declaration for ObserverListThreadSafeTraits. 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <class ObserverType> 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class ObserverListThreadSafe; 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// An UnboundMethod is a wrapper for a method where the actual object is 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// provided at Run dispatch time. 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <class T, class Method, class Params> 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class UnboundMethod { 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UnboundMethod(Method m, const Params& p) : m_(m), p_(p) { 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) COMPILE_ASSERT( 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (base::internal::ParamsUseScopedRefptrCorrectly<Params>::value), 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) badunboundmethodparams); 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Run(T* obj) const { 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DispatchToMethod(obj, m_, p_); 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Method m_; 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Params p_; 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This class is used to work around VS2005 not accepting: 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// friend class 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// base::RefCountedThreadSafe<ObserverListThreadSafe<ObserverType> >; 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Instead of friending the class, we could friend the actual function 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// which calls delete. However, this ends up being 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// RefCountedThreadSafe::DeleteInternal(), which is private. So we 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// define our own templated traits class so we can friend it. 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <class T> 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)struct ObserverListThreadSafeTraits { 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void Destruct(const ObserverListThreadSafe<T>* x) { 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) delete x; 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <class ObserverType> 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class ObserverListThreadSafe 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) : public base::RefCountedThreadSafe< 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverListThreadSafe<ObserverType>, 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverListThreadSafeTraits<ObserverType> > { 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typedef typename ObserverList<ObserverType>::NotificationType 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) NotificationType; 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverListThreadSafe() 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) : type_(ObserverListBase<ObserverType>::NOTIFY_ALL) {} 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit ObserverListThreadSafe(NotificationType type) : type_(type) {} 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Add an observer to the list. An observer should not be added to 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // the same list more than once. 1085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void AddObserver(ObserverType* obs) { 1095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If there is not a current MessageLoop, it is impossible to notify on it, 1105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // so do not add the observer. 111c2e0dbddbe15c98d52c4786dac06cb8952a8ae6dTorne (Richard Coles) if (!base::MessageLoop::current()) 1125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return; 1135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverList<ObserverType>* list = NULL; 1155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::PlatformThreadId thread_id = base::PlatformThread::CurrentId(); 1165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) { 1175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::AutoLock lock(list_lock_); 1185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (observer_lists_.find(thread_id) == observer_lists_.end()) 1195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) observer_lists_[thread_id] = new ObserverListContext(type_); 1205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) list = &(observer_lists_[thread_id]->list); 1215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) list->AddObserver(obs); 1235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Remove an observer from the list if it is in the list. 1265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If there are pending notifications in-transit to the observer, they will 1275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // be aborted. 1285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If the observer to be removed is in the list, RemoveObserver MUST 1295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // be called from the same thread which called AddObserver. 1305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void RemoveObserver(ObserverType* obs) { 1315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverListContext* context = NULL; 1325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverList<ObserverType>* list = NULL; 1335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::PlatformThreadId thread_id = base::PlatformThread::CurrentId(); 1345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) { 1355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::AutoLock lock(list_lock_); 1365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename ObserversListMap::iterator it = observer_lists_.find(thread_id); 1375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (it == observer_lists_.end()) { 1385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // This will happen if we try to remove an observer on a thread 1395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // we never added an observer for. 1405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return; 1415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) context = it->second; 1435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) list = &context->list; 1445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If we're about to remove the last observer from the list, 1465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // then we can remove this observer_list entirely. 1475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (list->HasObserver(obs) && list->size() == 1) 1485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) observer_lists_.erase(it); 1495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) list->RemoveObserver(obs); 1515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If RemoveObserver is called from a notification, the size will be 1535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // nonzero. Instead of deleting here, the NotifyWrapper will delete 1545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // when it finishes iterating. 1555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (list->size() == 0) 1565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) delete context; 1575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Verifies that the list is currently empty (i.e. there are no observers). 1605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void AssertEmpty() const { 1615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::AutoLock lock(list_lock_); 1625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(observer_lists_.empty()); 1635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Notify methods. 1665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Make a thread-safe callback to each Observer in the list. 1675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Note, these calls are effectively asynchronous. You cannot assume 1685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // that at the completion of the Notify call that all Observers have 1695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // been Notified. The notification may still be pending delivery. 1705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method> 1715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(Method m) { 1725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UnboundMethod<ObserverType, Method, Tuple0> method(m, MakeTuple()); 1735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Notify<Method, Tuple0>(method); 1745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method, class A> 1775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(Method m, const A& a) { 1785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UnboundMethod<ObserverType, Method, Tuple1<A> > method(m, MakeTuple(a)); 1795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Notify<Method, Tuple1<A> >(method); 1805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method, class A, class B> 1835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(Method m, const A& a, const B& b) { 1845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UnboundMethod<ObserverType, Method, Tuple2<A, B> > method( 1855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) m, MakeTuple(a, b)); 1865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Notify<Method, Tuple2<A, B> >(method); 1875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method, class A, class B, class C> 1905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(Method m, const A& a, const B& b, const C& c) { 1915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UnboundMethod<ObserverType, Method, Tuple3<A, B, C> > method( 1925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) m, MakeTuple(a, b, c)); 1935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Notify<Method, Tuple3<A, B, C> >(method); 1945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method, class A, class B, class C, class D> 1975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(Method m, const A& a, const B& b, const C& c, const D& d) { 1985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UnboundMethod<ObserverType, Method, Tuple4<A, B, C, D> > method( 1995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) m, MakeTuple(a, b, c, d)); 2005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Notify<Method, Tuple4<A, B, C, D> >(method); 2015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // TODO(mbelshe): Add more wrappers for Notify() with more arguments. 2045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 2065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // See comment above ObserverListThreadSafeTraits' definition. 2075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) friend struct ObserverListThreadSafeTraits<ObserverType>; 2085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) struct ObserverListContext { 2105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit ObserverListContext(NotificationType type) 2115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) : loop(base::MessageLoopProxy::current()), 2125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) list(type) { 2135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) scoped_refptr<base::MessageLoopProxy> loop; 2165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverList<ObserverType> list; 2175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(ObserverListContext); 2195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 2205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ~ObserverListThreadSafe() { 2222a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) STLDeleteValues(&observer_lists_); 2235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method, class Params> 2265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(const UnboundMethod<ObserverType, Method, Params>& method) { 2275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::AutoLock lock(list_lock_); 2285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename ObserversListMap::iterator it; 2295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it) { 2305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverListContext* context = (*it).second; 2315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) context->loop->PostTask( 2325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) FROM_HERE, 2335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Bind(&ObserverListThreadSafe<ObserverType>:: 2345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template NotifyWrapper<Method, Params>, this, context, method)); 2355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Wrapper which is called to fire the notifications for each thread's 2395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // ObserverList. This function MUST be called on the thread which owns 2405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // the unsafe ObserverList. 2415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) template <class Method, class Params> 2425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void NotifyWrapper(ObserverListContext* context, 2435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const UnboundMethod<ObserverType, Method, Params>& method) { 2445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Check that this list still needs notifications. 2465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) { 2475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::AutoLock lock(list_lock_); 2485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename ObserversListMap::iterator it = 2495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) observer_lists_.find(base::PlatformThread::CurrentId()); 2505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The ObserverList could have been removed already. In fact, it could 2525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // have been removed and then re-added! If the master list's loop 2535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // does not match this one, then we do not need to finish this 2545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // notification. 2555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (it == observer_lists_.end() || it->second != context) 2565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return; 2575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) { 2605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename ObserverList<ObserverType>::Iterator it(context->list); 2615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserverType* obs; 2625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while ((obs = it.GetNext()) != NULL) 2635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) method.Run(obs); 2645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If there are no more observers on the list, we can now delete it. 2675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (context->list.size() == 0) { 2685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) { 2695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::AutoLock lock(list_lock_); 2705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Remove |list| if it's not already removed. 2715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // This can happen if multiple observers got removed in a notification. 2725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // See http://crbug.com/55725. 2735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename ObserversListMap::iterator it = 2745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) observer_lists_.find(base::PlatformThread::CurrentId()); 2755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (it != observer_lists_.end() && it->second == context) 2765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) observer_lists_.erase(it); 2775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) delete context; 2795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Key by PlatformThreadId because in tests, clients can attempt to remove 2835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // observers without a MessageLoop. If this were keyed by MessageLoop, that 2845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // operation would be silently ignored, leaving garbage in the ObserverList. 2855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typedef std::map<base::PlatformThreadId, ObserverListContext*> 2865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserversListMap; 2875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) mutable base::Lock list_lock_; // Protects the observer_lists_. 2895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ObserversListMap observer_lists_; 2905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const NotificationType type_; 2915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(ObserverListThreadSafe); 2935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 2945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_OBSERVER_LIST_THREADSAFE_H_ 296