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