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
|
/*
* libjingle
* Copyright 2014 Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 TALK_BASE_ASYNCINVOKER_H_
#define TALK_BASE_ASYNCINVOKER_H_
#include "talk/base/asyncinvoker-inl.h"
#include "talk/base/bind.h"
#include "talk/base/sigslot.h"
#include "talk/base/scopedptrcollection.h"
#include "talk/base/thread.h"
namespace talk_base {
// Invokes function objects (aka functors) asynchronously on a Thread, and
// owns the lifetime of calls (ie, when this object is destroyed, calls in
// flight are cancelled). AsyncInvoker can optionally execute a user-specified
// function when the asynchronous call is complete, or operates in
// fire-and-forget mode otherwise.
//
// AsyncInvoker does not own the thread it calls functors on.
//
// A note about async calls and object lifetimes: users should
// be mindful of object lifetimes when calling functions asynchronously and
// ensure objects used by the function _cannot_ be deleted between the
// invocation and execution of the functor. AsyncInvoker is designed to
// help: any calls in flight will be cancelled when the AsyncInvoker used to
// make the call is destructed, and any calls executing will be allowed to
// complete before AsyncInvoker destructs.
//
// The easiest way to ensure lifetimes are handled correctly is to create a
// class that owns the Thread and AsyncInvoker objects, and then call its
// methods asynchronously as needed.
//
// Example:
// class MyClass {
// public:
// void FireAsyncTaskWithResult(Thread* thread, int x) {
// // Specify a callback to get the result upon completion.
// invoker_.AsyncInvoke<int>(
// thread, Bind(&MyClass::AsyncTaskWithResult, this, x),
// &MyClass::OnTaskComplete, this);
// }
// void FireAnotherAsyncTask(Thread* thread) {
// // No callback specified means fire-and-forget.
// invoker_.AsyncInvoke<void>(
// thread, Bind(&MyClass::AnotherAsyncTask, this));
//
// private:
// int AsyncTaskWithResult(int x) {
// // Some long running process...
// return x * x;
// }
// void AnotherAsyncTask() {
// // Some other long running process...
// }
// void OnTaskComplete(int result) { result_ = result; }
//
// AsyncInvoker invoker_;
// int result_;
// };
class AsyncInvoker : public MessageHandler {
public:
AsyncInvoker();
virtual ~AsyncInvoker();
// Call |functor| asynchronously on |thread|, with no callback upon
// completion. Returns immediately.
template <class ReturnT, class FunctorT>
void AsyncInvoke(Thread* thread,
const FunctorT& functor,
uint32 id = 0) {
AsyncClosure* closure =
new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(functor);
DoInvoke(thread, closure, id);
}
// Call |functor| asynchronously on |thread|, calling |callback| when done.
template <class ReturnT, class FunctorT, class HostT>
void AsyncInvoke(Thread* thread,
const FunctorT& functor,
void (HostT::*callback)(ReturnT),
HostT* callback_host,
uint32 id = 0) {
AsyncClosure* closure =
new RefCountedObject<NotifyingAsyncClosure<ReturnT, FunctorT, HostT> >(
this, Thread::Current(), functor, callback, callback_host);
DoInvoke(thread, closure, id);
}
// Call |functor| asynchronously on |thread|, calling |callback| when done.
// Overloaded for void return.
template <class ReturnT, class FunctorT, class HostT>
void AsyncInvoke(Thread* thread,
const FunctorT& functor,
void (HostT::*callback)(),
HostT* callback_host,
uint32 id = 0) {
AsyncClosure* closure =
new RefCountedObject<NotifyingAsyncClosure<void, FunctorT, HostT> >(
this, Thread::Current(), functor, callback, callback_host);
DoInvoke(thread, closure, id);
}
// Synchronously execute on |thread| all outstanding calls we own
// that are pending on |thread|, and wait for calls to complete
// before returning. Optionally filter by message id.
// The destructor will not wait for outstanding calls, so if that
// behavior is desired, call Flush() before destroying this object.
void Flush(Thread* thread, uint32 id = MQID_ANY);
// Signaled when this object is destructed.
sigslot::signal0<> SignalInvokerDestroyed;
private:
virtual void OnMessage(Message* msg);
void DoInvoke(Thread* thread, AsyncClosure* closure, uint32 id);
bool destroying_;
DISALLOW_COPY_AND_ASSIGN(AsyncInvoker);
};
} // namespace talk_base
#endif // TALK_BASE_ASYNCINVOKER_H_
|
