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112 lines
3.5 KiB
C++
112 lines
3.5 KiB
C++
// Copyright 2014 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "ui/events/platform/platform_event_source.h"
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#include <algorithm>
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#include "base/message_loop/message_loop.h"
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#include "ui/events/platform/platform_event_dispatcher.h"
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#include "ui/events/platform/platform_event_observer.h"
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#include "ui/events/platform/scoped_event_dispatcher.h"
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namespace ui {
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// static
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PlatformEventSource* PlatformEventSource::instance_ = NULL;
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PlatformEventSource::PlatformEventSource()
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: overridden_dispatcher_(NULL),
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overridden_dispatcher_restored_(false) {
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CHECK(!instance_) << "Only one platform event source can be created.";
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instance_ = this;
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}
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PlatformEventSource::~PlatformEventSource() {
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CHECK_EQ(this, instance_);
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instance_ = NULL;
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}
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PlatformEventSource* PlatformEventSource::GetInstance() { return instance_; }
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void PlatformEventSource::AddPlatformEventDispatcher(
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PlatformEventDispatcher* dispatcher) {
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CHECK(dispatcher);
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dispatchers_.AddObserver(dispatcher);
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OnDispatcherListChanged();
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}
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void PlatformEventSource::RemovePlatformEventDispatcher(
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PlatformEventDispatcher* dispatcher) {
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dispatchers_.RemoveObserver(dispatcher);
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OnDispatcherListChanged();
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}
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scoped_ptr<ScopedEventDispatcher> PlatformEventSource::OverrideDispatcher(
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PlatformEventDispatcher* dispatcher) {
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CHECK(dispatcher);
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overridden_dispatcher_restored_ = false;
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return make_scoped_ptr(
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new ScopedEventDispatcher(&overridden_dispatcher_, dispatcher));
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}
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void PlatformEventSource::StopCurrentEventStream() {
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}
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void PlatformEventSource::AddPlatformEventObserver(
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PlatformEventObserver* observer) {
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CHECK(observer);
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observers_.AddObserver(observer);
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}
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void PlatformEventSource::RemovePlatformEventObserver(
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PlatformEventObserver* observer) {
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observers_.RemoveObserver(observer);
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}
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uint32_t PlatformEventSource::DispatchEvent(PlatformEvent platform_event) {
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uint32_t action = POST_DISPATCH_PERFORM_DEFAULT;
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FOR_EACH_OBSERVER(PlatformEventObserver, observers_,
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WillProcessEvent(platform_event));
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// Give the overridden dispatcher a chance to dispatch the event first.
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if (overridden_dispatcher_)
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action = overridden_dispatcher_->DispatchEvent(platform_event);
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if ((action & POST_DISPATCH_PERFORM_DEFAULT) &&
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dispatchers_.might_have_observers()) {
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base::ObserverList<PlatformEventDispatcher>::Iterator iter(&dispatchers_);
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while (PlatformEventDispatcher* dispatcher = iter.GetNext()) {
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if (dispatcher->CanDispatchEvent(platform_event))
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action = dispatcher->DispatchEvent(platform_event);
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if (action & POST_DISPATCH_STOP_PROPAGATION)
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break;
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}
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}
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FOR_EACH_OBSERVER(PlatformEventObserver, observers_,
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DidProcessEvent(platform_event));
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// If an overridden dispatcher has been destroyed, then the platform
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// event-source should halt dispatching the current stream of events, and wait
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// until the next message-loop iteration for dispatching events. This lets any
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// nested message-loop to unwind correctly and any new dispatchers to receive
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// the correct sequence of events.
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if (overridden_dispatcher_restored_)
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StopCurrentEventStream();
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overridden_dispatcher_restored_ = false;
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return action;
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}
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void PlatformEventSource::OnDispatcherListChanged() {
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}
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void PlatformEventSource::OnOverriddenDispatcherRestored() {
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CHECK(overridden_dispatcher_);
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overridden_dispatcher_restored_ = true;
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}
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} // namespace ui
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