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
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
/*
* Copyright (C) 2013 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ExecutionContextTask_h
#define ExecutionContextTask_h
#include "core/CoreExport.h"
#include "platform/CrossThreadFunctional.h"
#include "wtf/Allocator.h"
#include "wtf/Functional.h"
#include "wtf/Noncopyable.h"
#include "wtf/PtrUtil.h"
#include "wtf/text/WTFString.h"
#include <type_traits>
namespace blink {
class ExecutionContext;
class CORE_EXPORT ExecutionContextTask {
WTF_MAKE_NONCOPYABLE(ExecutionContextTask);
USING_FAST_MALLOC(ExecutionContextTask);
public:
ExecutionContextTask() {}
virtual ~ExecutionContextTask() {}
virtual void performTask(ExecutionContext*) = 0;
void performTaskIfContextIsValid(ExecutionContext* context) {
if (context)
performTask(context);
}
};
namespace internal {
template <WTF::FunctionThreadAffinity threadAffinity>
void runCallClosureTask(
std::unique_ptr<Function<void(), threadAffinity>> closure,
ExecutionContext*) {
(*closure)();
}
template <WTF::FunctionThreadAffinity threadAffinity>
void runCallClosureTask(
std::unique_ptr<Function<void(ExecutionContext*), threadAffinity>> closure,
ExecutionContext* executionContext) {
(*closure)(executionContext);
}
template <typename T, WTF::FunctionThreadAffinity threadAffinity>
class CallClosureTask final : public ExecutionContextTask {
public:
static std::unique_ptr<CallClosureTask> create(
std::unique_ptr<Function<T, threadAffinity>> closure) {
return WTF::wrapUnique(new CallClosureTask(std::move(closure)));
}
private:
explicit CallClosureTask(std::unique_ptr<Function<T, threadAffinity>> closure)
: m_closure(std::move(closure)) {}
void performTask(ExecutionContext* executionContext) override {
runCallClosureTask(std::move(m_closure), executionContext);
}
std::unique_ptr<Function<T, threadAffinity>> m_closure;
};
// Do not use |create| other than in createCrossThreadTask and
// createSameThreadTask.
// See http://crbug.com/390851
template <typename T, WTF::FunctionThreadAffinity threadAffinity>
std::unique_ptr<CallClosureTask<T, threadAffinity>> createCallClosureTask(
std::unique_ptr<Function<T, threadAffinity>> closure) {
return CallClosureTask<T, threadAffinity>::create(std::move(closure));
}
} // namespace internal
// Create tasks passed within a single thread.
// When posting tasks within a thread, use |createSameThreadTask| instead
// of using |bind| directly to state explicitly that there is no need to care
// about thread safety when posting the task.
// When posting tasks across threads, use |createCrossThreadTask|.
template <typename FunctionType, typename... P>
std::unique_ptr<ExecutionContextTask> createSameThreadTask(
FunctionType function,
P&&... parameters) {
return internal::createCallClosureTask(
WTF::bind(function, std::forward<P>(parameters)...));
}
// createCrossThreadTask(...) is ExecutionContextTask version of
// crossThreadBind().
// Using WTF::bind() directly is not thread-safe due to temporary objects, see
// https://crbug.com/390851 for details.
//
// Example:
// void func1(int, const String&);
// createCrossThreadTask(func1, 42, str);
// func1(42, str2) will be called, where |str2| is a deep copy of
// |str| (created by str.isolatedCopy()).
//
// Don't (if you pass the task across threads):
// bind(func1, 42, str);
// bind(func1, 42, str.isolatedCopy());
//
// For functions:
// void functionEC(MP1, ..., MPn, ExecutionContext*);
// void function(MP1, ..., MPn);
// class C {
// void memberEC(MP1, ..., MPn, ExecutionContext*);
// void member(MP1, ..., MPn);
// };
// We create tasks represented by std::unique_ptr<ExecutionContextTask>:
// createCrossThreadTask(functionEC, const P1& p1, ..., const Pn& pn);
// createCrossThreadTask(memberEC, C* ptr, const P1& p1, ..., const Pn& pn);
// createCrossThreadTask(function, const P1& p1, ..., const Pn& pn);
// createCrossThreadTask(member, C* ptr, const P1& p1, ..., const Pn& pn);
// (|ptr| can also be WeakPtr<C> or other pointer-like types)
// and then the following are called on the target thread:
// functionEC(p1, ..., pn, context);
// ptr->memberEC(p1, ..., pn, context);
// function(p1, ..., pn);
// ptr->member(p1, ..., pn);
//
// ExecutionContext:
// |context| is supplied by the target thread.
//
// Deep copies by crossThreadBind():
// |ptr|, |p1|, ..., |pn| are processed by crossThreadBind() and thus
// CrossThreadCopier.
// You don't have to call manually e.g. isolatedCopy().
// To pass things that cannot be copied by CrossThreadCopier
// (e.g. pointers), use crossThreadUnretained() explicitly.
template <typename FunctionType, typename... P>
std::unique_ptr<ExecutionContextTask> createCrossThreadTask(
FunctionType function,
P&&... parameters) {
return internal::createCallClosureTask(
crossThreadBind(function, std::forward<P>(parameters)...));
}
} // namespace blink
#endif
|
