1/* 2 * Copyright (C) 2011 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 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. 12 * 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 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "config.h" 27#include "LayerChangesFlusher.h" 28 29#if USE(ACCELERATED_COMPOSITING) 30 31#include "AbstractCACFLayerTreeHost.h" 32#include <wtf/StdLibExtras.h> 33#include <wtf/Vector.h> 34 35namespace WebCore { 36 37LayerChangesFlusher& LayerChangesFlusher::shared() 38{ 39 DEFINE_STATIC_LOCAL(LayerChangesFlusher, flusher, ()); 40 return flusher; 41} 42 43LayerChangesFlusher::LayerChangesFlusher() 44 : m_hook(0) 45 , m_isCallingHosts(false) 46{ 47} 48 49void LayerChangesFlusher::flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost* host) 50{ 51 if (!m_hostsWithChangesToFlush.add(host).second || m_hook) 52 return; 53 54 setHook(); 55} 56 57void LayerChangesFlusher::cancelPendingFlush(AbstractCACFLayerTreeHost* host) 58{ 59 m_hostsWithChangesToFlush.remove(host); 60 61 if (!m_hostsWithChangesToFlush.isEmpty() || !m_hook) 62 return; 63 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. 66 if (m_isCallingHosts) 67 return; 68 69 removeHook(); 70} 71 72LRESULT LayerChangesFlusher::hookCallback(int code, WPARAM wParam, LPARAM lParam) 73{ 74 return shared().hookFired(code, wParam, lParam); 75} 76 77LRESULT LayerChangesFlusher::hookFired(int code, WPARAM wParam, LPARAM lParam) 78{ 79 ASSERT(m_hook); 80 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(); 86 87 m_isCallingHosts = true; 88 for (size_t i = 0; i < hosts.size(); ++i) 89 hosts[i]->flushPendingLayerChangesNow(); 90 m_isCallingHosts = false; 91 92 LRESULT result = ::CallNextHookEx(m_hook, code, wParam, lParam); 93 94 if (m_hostsWithChangesToFlush.isEmpty()) { 95 // We won't have any work to do next time around, so just remove our hook. 96 removeHook(); 97 } 98 99 return result; 100} 101 102void LayerChangesFlusher::setHook() 103{ 104 ASSERT(!m_hook); 105 ASSERT(!m_isCallingHosts); 106 107 DWORD threadID = ::GetCurrentThreadId(); 108 109 m_hook = ::SetWindowsHookExW(WH_GETMESSAGE, hookCallback, 0, threadID); 110 ASSERT_WITH_MESSAGE(m_hook, "::SetWindowsHookExW failed with error %lu", ::GetLastError()); 111 112 // 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); 115} 116 117void LayerChangesFlusher::removeHook() 118{ 119 ASSERT(m_hook); 120 ASSERT(!m_isCallingHosts); 121 122 if (!::UnhookWindowsHookEx(m_hook)) 123 ASSERT_WITH_MESSAGE(false, "::UnhookWindowsHookEx failed with error %lu", ::GetLastError()); 124 125 m_hook = 0; 126} 127 128} // namespace WebCore 129 130#endif // USE(ACCELERATED_COMPOSITING) 131