1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/chrome/common/notification_service.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,100 @@
1.4 +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +// This file describes a central switchboard for notifications that might
1.9 +// happen in various parts of the application, and allows users to register
1.10 +// observers for various classes of events that they're interested in.
1.11 +
1.12 +#ifndef CHROME_COMMON_NOTIFICATION_SERVICE_H_
1.13 +#define CHROME_COMMON_NOTIFICATION_SERVICE_H_
1.14 +
1.15 +#include <map>
1.16 +
1.17 +#include "base/observer_list.h"
1.18 +#include "chrome/common/notification_details.h"
1.19 +#include "chrome/common/notification_observer.h"
1.20 +#include "chrome/common/notification_source.h"
1.21 +#include "chrome/common/notification_type.h"
1.22 +
1.23 +class NotificationObserver;
1.24 +
1.25 +class NotificationService {
1.26 + public:
1.27 + // Returns the NotificationService object for the current thread, or NULL if
1.28 + // none.
1.29 + static NotificationService* current();
1.30 +
1.31 + // Normally instantiated when the thread is created. Not all threads have
1.32 + // a NotificationService. Only one instance should be created per thread.
1.33 + NotificationService();
1.34 + ~NotificationService();
1.35 +
1.36 + // Registers a NotificationObserver to be called whenever a matching
1.37 + // notification is posted. Observer is a pointer to an object subclassing
1.38 + // NotificationObserver to be notified when an event matching the other two
1.39 + // parameters is posted to this service. Type is the type of events to
1.40 + // be notified about (or NOTIFY_ALL to receive events of all types).
1.41 + // Source is a NotificationSource object (created using
1.42 + // "Source<classname>(pointer)"), if this observer only wants to
1.43 + // receive events from that object, or NotificationService::AllSources()
1.44 + // to receive events from all sources.
1.45 + //
1.46 + // A given observer can be registered only once for each combination of
1.47 + // type and source. If the same object is registered more than once,
1.48 + // it must be removed for each of those combinations of type and source later.
1.49 + //
1.50 + // The caller retains ownership of the object pointed to by observer.
1.51 + void AddObserver(NotificationObserver* observer,
1.52 + NotificationType type, const NotificationSource& source);
1.53 +
1.54 + // Removes the object pointed to by observer from receiving notifications
1.55 + // that match type and source. If no object matching the parameters is
1.56 + // currently registered, this method is a no-op.
1.57 + void RemoveObserver(NotificationObserver* observer,
1.58 + NotificationType type, const NotificationSource& source);
1.59 +
1.60 + // Synchronously posts a notification to all interested observers.
1.61 + // Source is a reference to a NotificationSource object representing
1.62 + // the object originating the notification (can be
1.63 + // NotificationService::AllSources(), in which case
1.64 + // only observers interested in all sources will be notified).
1.65 + // Details is a reference to an object containing additional data about
1.66 + // the notification. If no additional data is needed, NoDetails() is used.
1.67 + // There is no particular order in which the observers will be notified.
1.68 + void Notify(NotificationType type,
1.69 + const NotificationSource& source,
1.70 + const NotificationDetails& details);
1.71 +
1.72 + // Returns a NotificationSource that represents all notification sources
1.73 + // (for the purpose of registering an observer for events from all sources).
1.74 + static Source<void> AllSources() { return Source<void>(NULL); }
1.75 +
1.76 + // Returns a NotificationDetails object that represents a lack of details
1.77 + // associated with a notification. (This is effectively a null pointer.)
1.78 + static Details<void> NoDetails() { return Details<void>(NULL); }
1.79 +
1.80 + private:
1.81 + typedef base::ObserverList<NotificationObserver> NotificationObserverList;
1.82 + typedef std::map<uintptr_t, NotificationObserverList*> NotificationSourceMap;
1.83 +
1.84 + // Convenience function to determine whether a source has a
1.85 + // NotificationObserverList in the given map;
1.86 + static bool HasKey(const NotificationSourceMap& map,
1.87 + const NotificationSource& source);
1.88 +
1.89 + // Keeps track of the observers for each type of notification.
1.90 + // Until we get a prohibitively large number of notification types,
1.91 + // a simple array is probably the fastest way to dispatch.
1.92 + NotificationSourceMap observers_[NotificationType::NOTIFICATION_TYPE_COUNT];
1.93 +
1.94 +#ifndef NDEBUG
1.95 + // Used to check to see that AddObserver and RemoveObserver calls are
1.96 + // balanced.
1.97 + int observer_counts_[NotificationType::NOTIFICATION_TYPE_COUNT];
1.98 +#endif
1.99 +
1.100 + DISALLOW_COPY_AND_ASSIGN(NotificationService);
1.101 +};
1.102 +
1.103 +#endif // CHROME_COMMON_NOTIFICATION_SERVICE_H_
