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 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#include "AbstractCACFLayerTreeHost.h" 30#include "StructuredExceptionHandlerSuppressor.h" 31#include <wtf/StdLibExtras.h> 32#include <wtf/Vector.h> 33 34namespace WebCore { 35 36LayerChangesFlusher& LayerChangesFlusher::shared() 37{ 38 DEPRECATED_DEFINE_STATIC_LOCAL(LayerChangesFlusher, flusher, ()); 39 return flusher; 40} 41 42LayerChangesFlusher::LayerChangesFlusher() 43 : m_hook(0) 44 , m_isCallingHosts(false) 45{ 46} 47 48void LayerChangesFlusher::flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost* host) 49{ 50 if (!m_hostsWithChangesToFlush.add(host).isNewEntry || m_hook) 51 return; 52 53 setHook(); 54} 55 56void LayerChangesFlusher::cancelPendingFlush(AbstractCACFLayerTreeHost* host) 57{ 58 m_hostsWithChangesToFlush.remove(host); 59 60 if (!m_hostsWithChangesToFlush.isEmpty() || !m_hook) 61 return; 62 63 // We handle removing the hook when we finish calling out to the hosts, so we shouldn't 64 // mess with it while we're in the process of calling them. 65 if (m_isCallingHosts) 66 return; 67 68 removeHook(); 69} 70 71LRESULT LayerChangesFlusher::hookCallback(int code, WPARAM wParam, LPARAM lParam) 72{ 73 // Supress the exception handler Windows puts around all hook calls so we can 74 // crash for debugging purposes if an exception is hit. 75 ExceptionRegistration registrationStruct; // Note: must be stack allocated. 76 StructuredExceptionHandlerSuppressor supressor(registrationStruct); 77 return shared().hookFired(code, wParam, lParam); 78} 79 80LRESULT LayerChangesFlusher::hookFired(int code, WPARAM wParam, LPARAM lParam) 81{ 82 ASSERT(m_hook); 83 84 // Calling out to the hosts can cause m_hostsWithChangesToFlush to be modified, so we copy it 85 // into a Vector first. 86 Vector<AbstractCACFLayerTreeHost*> hosts; 87 copyToVector(m_hostsWithChangesToFlush, hosts); 88 m_hostsWithChangesToFlush.clear(); 89 90 m_isCallingHosts = true; 91 for (size_t i = 0; i < hosts.size(); ++i) 92 hosts[i]->flushPendingLayerChangesNow(); 93 m_isCallingHosts = false; 94 95 LRESULT result = ::CallNextHookEx(m_hook, code, wParam, lParam); 96 97 if (m_hook && m_hostsWithChangesToFlush.isEmpty()) { 98 // We won't have any work to do next time around, so just remove our hook. 99 removeHook(); 100 } 101 102 return result; 103} 104 105void LayerChangesFlusher::setHook() 106{ 107 ASSERT(!m_hook); 108 ASSERT(!m_isCallingHosts); 109 110 DWORD threadID = ::GetCurrentThreadId(); 111 112 m_hook = ::SetWindowsHookExW(WH_GETMESSAGE, hookCallback, 0, threadID); 113 ASSERT_WITH_MESSAGE(m_hook, "::SetWindowsHookExW failed with error %lu", ::GetLastError()); 114 115 // Post a message to the message queue to prevent ::GetMessage from blocking, which will ensure 116 // our hook is called soon. 117 ::PostThreadMessageW(threadID, WM_NULL, 0, 0); 118} 119 120void LayerChangesFlusher::removeHook() 121{ 122 ASSERT(m_hook); 123 ASSERT(!m_isCallingHosts); 124 125 if (!::UnhookWindowsHookEx(m_hook)) 126 ASSERT_WITH_MESSAGE(false, "::UnhookWindowsHookEx failed with error %lu", ::GetLastError()); 127 128 m_hook = 0; 129} 130 131} // namespace WebCore 132