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/*
* Copyright (C) 2011 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "LayerChangesFlusher.h"
#if USE(ACCELERATED_COMPOSITING)
#include "AbstractCACFLayerTreeHost.h"
#include "StructuredExceptionHandlerSupressor.h"
#include <wtf/StdLibExtras.h>
#include <wtf/Vector.h>
namespace WebCore {
LayerChangesFlusher& LayerChangesFlusher::shared()
{
DEFINE_STATIC_LOCAL(LayerChangesFlusher, flusher, ());
return flusher;
}
LayerChangesFlusher::LayerChangesFlusher()
: m_hook(0)
, m_isCallingHosts(false)
{
}
void LayerChangesFlusher::flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost* host)
{
if (!m_hostsWithChangesToFlush.add(host).isNewEntry || m_hook)
return;
setHook();
}
void LayerChangesFlusher::cancelPendingFlush(AbstractCACFLayerTreeHost* host)
{
m_hostsWithChangesToFlush.remove(host);
if (!m_hostsWithChangesToFlush.isEmpty() || !m_hook)
return;
// We handle removing the hook when we finish calling out to the hosts, so we shouldn't
// mess with it while we're in the process of calling them.
if (m_isCallingHosts)
return;
removeHook();
}
LRESULT LayerChangesFlusher::hookCallback(int code, WPARAM wParam, LPARAM lParam)
{
// Supress the exception handler Windows puts around all hook calls so we can
// crash for debugging purposes if an exception is hit.
StructuredExceptionHandlerSupressor supressor;
return shared().hookFired(code, wParam, lParam);
}
LRESULT LayerChangesFlusher::hookFired(int code, WPARAM wParam, LPARAM lParam)
{
ASSERT(m_hook);
// Calling out to the hosts can cause m_hostsWithChangesToFlush to be modified, so we copy it
// into a Vector first.
Vector<AbstractCACFLayerTreeHost*> hosts;
copyToVector(m_hostsWithChangesToFlush, hosts);
m_hostsWithChangesToFlush.clear();
m_isCallingHosts = true;
for (size_t i = 0; i < hosts.size(); ++i)
hosts[i]->flushPendingLayerChangesNow();
m_isCallingHosts = false;
LRESULT result = ::CallNextHookEx(m_hook, code, wParam, lParam);
if (m_hook && m_hostsWithChangesToFlush.isEmpty()) {
// We won't have any work to do next time around, so just remove our hook.
removeHook();
}
return result;
}
void LayerChangesFlusher::setHook()
{
ASSERT(!m_hook);
ASSERT(!m_isCallingHosts);
DWORD threadID = ::GetCurrentThreadId();
m_hook = ::SetWindowsHookExW(WH_GETMESSAGE, hookCallback, 0, threadID);
ASSERT_WITH_MESSAGE(m_hook, "::SetWindowsHookExW failed with error %lu", ::GetLastError());
// Post a message to the message queue to prevent ::GetMessage from blocking, which will ensure
// our hook is called soon.
::PostThreadMessageW(threadID, WM_NULL, 0, 0);
}
void LayerChangesFlusher::removeHook()
{
ASSERT(m_hook);
ASSERT(!m_isCallingHosts);
if (!::UnhookWindowsHookEx(m_hook))
ASSERT_WITH_MESSAGE(false, "::UnhookWindowsHookEx failed with error %lu", ::GetLastError());
m_hook = 0;
}
} // namespace WebCore
#endif // USE(ACCELERATED_COMPOSITING)
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