1/* 2 * Copyright (C) 2011, 2013 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 "StructuredExceptionHandlerSuppressor.h" 33#include <wtf/StdLibExtras.h> 34#include <wtf/Vector.h> 35 36namespace WebCore { 37 38LayerChangesFlusher& LayerChangesFlusher::shared() 39{ 40 DEFINE_STATIC_LOCAL(LayerChangesFlusher, flusher, ()); 41 return flusher; 42} 43 44LayerChangesFlusher::LayerChangesFlusher() 45 : m_hook(0) 46 , m_isCallingHosts(false) 47{ 48} 49 50void LayerChangesFlusher::flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost* host) 51{ 52 if (!m_hostsWithChangesToFlush.add(host).isNewEntry || m_hook) 53 return; 54 55 setHook(); 56} 57 58void LayerChangesFlusher::cancelPendingFlush(AbstractCACFLayerTreeHost* host) 59{ 60 m_hostsWithChangesToFlush.remove(host); 61 62 if (!m_hostsWithChangesToFlush.isEmpty() || !m_hook) 63 return; 64 65 // We handle removing the hook when we finish calling out to the hosts, so we shouldn't 66 // mess with it while we're in the process of calling them. 67 if (m_isCallingHosts) 68 return; 69 70 removeHook(); 71} 72 73LRESULT LayerChangesFlusher::hookCallback(int code, WPARAM wParam, LPARAM lParam) 74{ 75 // Supress the exception handler Windows puts around all hook calls so we can 76 // crash for debugging purposes if an exception is hit. 77 ExceptionRegistration registrationStruct; // Note: must be stack allocated. 78 StructuredExceptionHandlerSuppressor supressor(registrationStruct); 79 return shared().hookFired(code, wParam, lParam); 80} 81 82LRESULT LayerChangesFlusher::hookFired(int code, WPARAM wParam, LPARAM lParam) 83{ 84 ASSERT(m_hook); 85 86 // Calling out to the hosts can cause m_hostsWithChangesToFlush to be modified, so we copy it 87 // into a Vector first. 88 Vector<AbstractCACFLayerTreeHost*> hosts; 89 copyToVector(m_hostsWithChangesToFlush, hosts); 90 m_hostsWithChangesToFlush.clear(); 91 92 m_isCallingHosts = true; 93 for (size_t i = 0; i < hosts.size(); ++i) 94 hosts[i]->flushPendingLayerChangesNow(); 95 m_isCallingHosts = false; 96 97 LRESULT result = ::CallNextHookEx(m_hook, code, wParam, lParam); 98 99 if (m_hook && m_hostsWithChangesToFlush.isEmpty()) { 100 // We won't have any work to do next time around, so just remove our hook. 101 removeHook(); 102 } 103 104 return result; 105} 106 107void LayerChangesFlusher::setHook() 108{ 109 ASSERT(!m_hook); 110 ASSERT(!m_isCallingHosts); 111 112 DWORD threadID = ::GetCurrentThreadId(); 113 114 m_hook = ::SetWindowsHookExW(WH_GETMESSAGE, hookCallback, 0, threadID); 115 ASSERT_WITH_MESSAGE(m_hook, "::SetWindowsHookExW failed with error %lu", ::GetLastError()); 116 117 // Post a message to the message queue to prevent ::GetMessage from blocking, which will ensure 118 // our hook is called soon. 119 ::PostThreadMessageW(threadID, WM_NULL, 0, 0); 120} 121 122void LayerChangesFlusher::removeHook() 123{ 124 ASSERT(m_hook); 125 ASSERT(!m_isCallingHosts); 126 127 if (!::UnhookWindowsHookEx(m_hook)) 128 ASSERT_WITH_MESSAGE(false, "::UnhookWindowsHookEx failed with error %lu", ::GetLastError()); 129 130 m_hook = 0; 131} 132 133} // namespace WebCore 134 135#endif // USE(ACCELERATED_COMPOSITING) 136