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
35 namespace WebCore {
36
shared()37 LayerChangesFlusher& LayerChangesFlusher::shared()
38 {
39 DEFINE_STATIC_LOCAL(LayerChangesFlusher, flusher, ());
40 return flusher;
41 }
42
LayerChangesFlusher()43 LayerChangesFlusher::LayerChangesFlusher()
44 : m_hook(0)
45 , m_isCallingHosts(false)
46 {
47 }
48
flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost * host)49 void LayerChangesFlusher::flushPendingLayerChangesSoon(AbstractCACFLayerTreeHost* host)
50 {
51 if (!m_hostsWithChangesToFlush.add(host).second || m_hook)
52 return;
53
54 setHook();
55 }
56
cancelPendingFlush(AbstractCACFLayerTreeHost * host)57 void 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
hookCallback(int code,WPARAM wParam,LPARAM lParam)72 LRESULT LayerChangesFlusher::hookCallback(int code, WPARAM wParam, LPARAM lParam)
73 {
74 return shared().hookFired(code, wParam, lParam);
75 }
76
hookFired(int code,WPARAM wParam,LPARAM lParam)77 LRESULT 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
setHook()102 void 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
removeHook()117 void 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