2 * Copyright (C) 2011 Apple Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #include "LayerChangesFlusher.h"
29 #if USE(ACCELERATED_COMPOSITING)
31 #include "AbstractCACFLayerTreeHost.h"
32 #include <wtf/StdLibExtras.h>
33 #include <wtf/Vector.h>
37 LayerChangesFlusher& LayerChangesFlusher::shared()
39 DEFINE_STATIC_LOCAL(LayerChangesFlusher, flusher, ());
43 LayerChangesFlusher::LayerChangesFlusher()
45 , m_isCallingHosts(false)
49 void LayerChangesFlusher::flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost* host)
51 if (!m_hostsWithChangesToFlush.add(host).second || m_hook)
57 void LayerChangesFlusher::cancelPendingFlush(AbstractCACFLayerTreeHost* host)
59 m_hostsWithChangesToFlush.remove(host);
61 if (!m_hostsWithChangesToFlush.isEmpty() || !m_hook)
64 // We handle removing the hook when we finish calling out to the hosts, so we shouldn't
65 // mess with it while we're in the process of calling them.
72 LRESULT LayerChangesFlusher::hookCallback(int code, WPARAM wParam, LPARAM lParam)
74 return shared().hookFired(code, wParam, lParam);
77 LRESULT LayerChangesFlusher::hookFired(int code, WPARAM wParam, LPARAM lParam)
81 // Calling out to the hosts can cause m_hostsWithChangesToFlush to be modified, so we copy it
82 // into a Vector first.
83 Vector<AbstractCACFLayerTreeHost*> hosts;
84 copyToVector(m_hostsWithChangesToFlush, hosts);
85 m_hostsWithChangesToFlush.clear();
87 m_isCallingHosts = true;
88 for (size_t i = 0; i < hosts.size(); ++i)
89 hosts[i]->flushPendingLayerChangesNow();
90 m_isCallingHosts = false;
92 LRESULT result = ::CallNextHookEx(m_hook, code, wParam, lParam);
94 if (m_hostsWithChangesToFlush.isEmpty()) {
95 // We won't have any work to do next time around, so just remove our hook.
102 void LayerChangesFlusher::setHook()
105 ASSERT(!m_isCallingHosts);
107 DWORD threadID = ::GetCurrentThreadId();
109 m_hook = ::SetWindowsHookExW(WH_GETMESSAGE, hookCallback, 0, threadID);
110 ASSERT_WITH_MESSAGE(m_hook, "::SetWindowsHookExW failed with error %lu", ::GetLastError());
112 // Post a message to the message queue to prevent ::GetMessage from blocking, which will ensure
113 // our hook is called soon.
114 ::PostThreadMessageW(threadID, WM_NULL, 0, 0);
117 void LayerChangesFlusher::removeHook()
120 ASSERT(!m_isCallingHosts);
122 if (!::UnhookWindowsHookEx(m_hook))
123 ASSERT_WITH_MESSAGE(false, "::UnhookWindowsHookEx failed with error %lu", ::GetLastError());
128 } // namespace WebCore
130 #endif // USE(ACCELERATED_COMPOSITING)