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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 "config.h"
#include "core/frame/PlatformEventDispatcher.h"
#include "core/frame/PlatformEventController.h"
#include "wtf/TemporaryChange.h"
namespace blink {
PlatformEventDispatcher::PlatformEventDispatcher()
: m_needsPurge(false)
, m_isDispatching(false)
{
}
void PlatformEventDispatcher::addController(PlatformEventController* controller)
{
bool wasEmpty = m_controllers.isEmpty();
if (!m_controllers.contains(controller))
m_controllers.append(controller);
if (wasEmpty)
startListening();
}
void PlatformEventDispatcher::removeController(PlatformEventController* controller)
{
// Do not actually remove the controller from the vector, instead zero them out.
// The zeros are removed in these two cases:
// 1. either immediately if we are not dispatching any events,
// 2. or after events to all controllers have dispatched (see notifyControllers()).
// This is to correctly handle the re-entrancy case when a controller is destroyed
// while the events are still being dispatched.
size_t index = m_controllers.find(controller);
if (index == kNotFound)
return;
m_controllers[index] = nullptr;
m_needsPurge = true;
if (!m_isDispatching)
purgeControllers();
}
void PlatformEventDispatcher::purgeControllers()
{
ASSERT(m_needsPurge);
size_t i = 0;
while (i < m_controllers.size()) {
if (!m_controllers[i]) {
m_controllers[i] = m_controllers.last();
m_controllers.removeLast();
} else {
++i;
}
}
m_needsPurge = false;
if (m_controllers.isEmpty())
stopListening();
}
void PlatformEventDispatcher::notifyControllers()
{
{
TemporaryChange<bool> changeIsDispatching(m_isDispatching, true);
// Don't notify controllers removed or added during event dispatch.
size_t size = m_controllers.size();
for (size_t i = 0; i < size; ++i) {
if (m_controllers[i])
m_controllers[i]->didUpdateData();
}
}
if (m_needsPurge)
purgeControllers();
}
void PlatformEventDispatcher::trace(Visitor* visitor)
{
#if ENABLE(OILPAN)
// Trace the backing store, the weak(&bare) element references won't be.
visitor->trace(m_controllers);
visitor->registerWeakMembers<PlatformEventDispatcher, &PlatformEventDispatcher::clearWeakMembers>(this);
#endif
}
#if ENABLE(OILPAN)
void PlatformEventDispatcher::clearWeakMembers(Visitor* visitor)
{
for (size_t i = 0; i < m_controllers.size(); ++i) {
if (!visitor->isAlive(m_controllers[i])) {
m_controllers[i] = nullptr;
m_needsPurge = true;
}
}
// Next notification will purge the empty slots.
}
#endif
} // namespace blink
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