blob: 7bd60d08a4620f4f42362a2955b30ee1907cc166 [file] [log] [blame]
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stdint.h>
#include <map>
#include <memory>
#include <vector>
#include "base/auto_reset.h"
#include "base/macros.h"
#include "base/observer_list.h"
#include "ui/events/events_export.h"
#include "ui/events/platform_event.h"
namespace ui {
class PlatformEventDispatcher;
class PlatformEventObserver;
class ScopedEventDispatcher;
namespace test {
class PlatformEventSourceTestAPI;
// PlatformEventSource receives events from a source and dispatches the events
// to the appropriate dispatchers.
class EVENTS_EXPORT PlatformEventSource {
virtual ~PlatformEventSource();
// Returns the thread-local singleton.
static PlatformEventSource* GetInstance();
// Returns true when platform events should not be sent to the rest of the
// pipeline. Mainly when Chrome is run in a test environment and it doesn't
// expect any events from the platform and all events are synthesized by the
// test environment.
static bool ShouldIgnoreNativePlatformEvents();
// Sets whether to ignore platform events and drop them or to forward them to
// the rest of the input pipeline.
static void SetIgnoreNativePlatformEvents(bool ignore_events);
// Adds a dispatcher to the dispatcher list. If a dispatcher is added during
// dispatching an event, then the newly added dispatcher also receives that
// event.
void AddPlatformEventDispatcher(PlatformEventDispatcher* dispatcher);
// Removes a dispatcher from the dispatcher list. Dispatchers can safely be
// removed from the dispatcher list during an event is being dispatched,
// without affecting the dispatch of the event to other existing dispatchers.
void RemovePlatformEventDispatcher(PlatformEventDispatcher* dispatcher);
// Installs a PlatformEventDispatcher that receives all the events. The
// dispatcher can process the event, or request that the default dispatchers
// be invoked by setting |POST_DISPATCH_PERFORM_DEFAULT| flag from the
// |DispatchEvent()| override.
// The returned |ScopedEventDispatcher| object is a handler for the overridden
// dispatcher. When this handler is destroyed, it removes the overridden
// dispatcher, and restores the previous override-dispatcher (or NULL if there
// wasn't any).
std::unique_ptr<ScopedEventDispatcher> OverrideDispatcher(
PlatformEventDispatcher* dispatcher);
// Called to indicate that the source should stop dispatching the current
// stream of events and wait until the next iteration of the message-loop to
// dispatch the rest of the events.
virtual void StopCurrentEventStream();
void AddPlatformEventObserver(PlatformEventObserver* observer);
void RemovePlatformEventObserver(PlatformEventObserver* observer);
// Creates PlatformEventSource and sets it as a thread-local singleton.
static std::unique_ptr<PlatformEventSource> CreateDefault();
typedef base::ObserverList<PlatformEventObserver>::Unchecked
// Dispatches |platform_event| to the dispatchers. If there is an override
// dispatcher installed using |OverrideDispatcher()|, then that dispatcher
// receives the event first. |POST_DISPATCH_QUIT_LOOP| flag is set in the
// returned value if the event-source should stop dispatching events at the
// current message-loop iteration.
virtual uint32_t DispatchEvent(PlatformEvent platform_event);
PlatformEventObserverList& observers() { return observers_; }
friend class ScopedEventDispatcher;
friend class test::PlatformEventSourceTestAPI;
// This is invoked when the list of dispatchers changes (i.e. a new dispatcher
// is added, or a dispatcher is removed).
virtual void OnDispatcherListChanged();
void OnOverriddenDispatcherRestored();
// Use an base::ObserverList<> instead of an std::vector<> to store the list
// of
// dispatchers, so that adding/removing dispatchers during an event dispatch
// is well-defined.
typedef base::ObserverList<PlatformEventDispatcher>::Unchecked
PlatformEventDispatcherList dispatchers_;
PlatformEventDispatcher* overridden_dispatcher_;
// Used to keep track of whether the current override-dispatcher has been
// reset and a previous override-dispatcher has been restored.
bool overridden_dispatcher_restored_;
static bool ignore_native_platform_events_;
PlatformEventObserverList observers_;
} // namespace ui