1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/*
* Copyright (C) 2015 Igalia S.L
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#pragma once
#include <functional>
#include <wtf/Atomics.h>
#include <wtf/Lock.h>
#include <wtf/MainThread.h>
#include <wtf/RunLoop.h>
#include <wtf/ThreadSafeRefCounted.h>
namespace WebCore {
template <typename T>
class MainThreadNotifier final : public ThreadSafeRefCounted<MainThreadNotifier<T>> {
public:
static Ref<MainThreadNotifier> create()
{
return adoptRef(*new MainThreadNotifier());
}
~MainThreadNotifier()
{
ASSERT(!m_isValid.load());
}
bool isValid() const { return m_isValid.load(); }
template<typename F>
void notify(T notificationType, F&& callbackFunctor)
{
ASSERT(m_isValid.load());
// Assert that there is only one bit on at a time.
ASSERT(!(static_cast<int>(notificationType) & (static_cast<int>(notificationType) - 1)));
if (isMainThread()) {
removePendingNotification(notificationType);
callbackFunctor();
return;
}
if (!addPendingNotification(notificationType))
return;
RunLoop::main().dispatch([this, protectedThis = Ref { *this }, notificationType, callback = Function<void()>(WTFMove(callbackFunctor))] {
if (!m_isValid.load())
return;
if (removePendingNotification(notificationType))
callback();
});
}
template<typename F>
void notifyAndWait(T notificationType, F&& callbackFunctor)
{
Lock lock;
Condition condition;
notify(notificationType, [functor = WTFMove(callbackFunctor), &condition, &lock] {
functor();
Locker locker { lock };
condition.notifyOne();
});
if (!isMainThread()) {
Locker locker { lock };
condition.wait(lock);
}
}
void cancelPendingNotifications(unsigned mask = 0)
{
ASSERT(m_isValid.load());
Locker locker { m_pendingNotificationsLock };
if (mask)
m_pendingNotifications &= ~mask;
else
m_pendingNotifications = 0;
}
void invalidate()
{
ASSERT(m_isValid.load());
m_isValid.store(false);
}
private:
MainThreadNotifier()
{
m_isValid.store(true);
}
bool addPendingNotification(T notificationType)
{
Locker locker { m_pendingNotificationsLock };
if (notificationType & m_pendingNotifications)
return false;
m_pendingNotifications |= notificationType;
return true;
}
bool removePendingNotification(T notificationType)
{
Locker locker { m_pendingNotificationsLock };
if (notificationType & m_pendingNotifications) {
m_pendingNotifications &= ~notificationType;
return true;
}
return false;
}
Lock m_pendingNotificationsLock;
unsigned m_pendingNotifications WTF_GUARDED_BY_LOCK(m_pendingNotificationsLock) { 0 };
Atomic<bool> m_isValid;
};
} // namespace WebCore
|
