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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
// **************************************************************************
// * This file is part of the FreeFileSync project. It is distributed under *
// * GNU General Public License: http://www.gnu.org/licenses/gpl.html *
// * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved *
// **************************************************************************
#ifndef BOOST_THREAD_WRAP_H
#define BOOST_THREAD_WRAP_H
//temporary solution until C++11 thread becomes fully available
#include <memory>
//fix this pathetic boost thread warning mess
#ifdef __MINGW32__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wswitch-enum"
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
#pragma GCC diagnostic ignored "-Wshadow"
#endif
#ifdef _MSC_VER
#pragma warning(disable : 4702) //unreachable code
#pragma warning(disable : 4913) //user defined binary operator ',' exists but no overload could convert all operands, default built-in binary operator ',' used
#endif
#include <boost/thread.hpp>
#ifdef __MINGW32__
#pragma GCC diagnostic pop
#endif
#ifdef _MSC_VER
#pragma warning(default : 4702)
#pragma warning(default : 4913)
#endif
namespace zen
{
//until std::async is available:
/*
Example:
Zstring dirname = ...
auto ft = zen::async([=](){ return zen::dirExists(dirname); });
if (ft.timed_wait(boost::posix_time::milliseconds(200)) && ft.get())
//dir exising
*/
template <class Function>
auto async(Function fun) -> boost::unique_future<decltype(fun())>;
//wait for all with a time limit: return true if *all* results are available!
template<class InputIterator, class Duration>
bool wait_for_all_timed(InputIterator first, InputIterator last, const Duration& wait_duration);
//wait until first job is successful or all failed
template <class T>
class RunUntilFirstHit
{
public:
RunUntilFirstHit();
template <class Fun>
void addJob(Fun f); //f must return a std::unique_ptr<T> containing a value if successful
template <class Duration>
bool timedWait(const Duration& duration) const; //true: "get()" is ready, false: time elapsed
//return first value or none if all jobs failed; blocks until result is ready!
std::unique_ptr<T> get() const; //may be called only once!
private:
class AsyncResult;
std::shared_ptr<AsyncResult> result;
size_t jobsTotal;
};
//###################### implementation ######################
#ifndef BOOST_HAS_THREADS
#error just some paranoia check...
#endif
template <class T, class Function> inline
auto async2(Function fun) -> boost::unique_future<T> //support for workaround of VS2010 bug: bool (*fun)(); decltype(fun()) == int!
{
boost::packaged_task<T> pt(fun);
auto fut = pt.get_future();
boost::thread t(std::move(pt));
t.detach(); //we have to be explicit since C++11: [thread.thread.destr] ~thread() calls std::terminate() if joinable()!!!
return std::move(fut); //compiler error without "move", why needed???
}
template <class Function> inline
auto async(Function fun) -> boost::unique_future<decltype(fun())> { return async2<decltype(fun())>(fun); }
template<class InputIterator, class Duration> inline
bool wait_for_all_timed(InputIterator first, InputIterator last, const Duration& wait_duration)
{
const boost::system_time endTime = boost::get_system_time() + wait_duration;
while (first != last)
{
if (!first->timed_wait_until(endTime))
return false; //time elapsed
++first;
}
return true;
}
template <class T>
class RunUntilFirstHit<T>::AsyncResult
{
public:
AsyncResult() :
#ifndef NDEBUG
returnedResult(false),
#endif
jobsFinished(0) {}
//context: worker threads
void reportFinished(std::unique_ptr<T>&& result)
{
{
boost::unique_lock<boost::mutex> dummy(lockResult);
++jobsFinished;
if (!result_)
result_ = std::move(result);
}
conditionJobDone.notify_one();
//condition handling, see: http://www.boost.org/doc/libs/1_43_0/doc/html/thread/synchronization.html#thread.synchronization.condvar_ref
}
//context: main thread
template <class Duration>
bool waitForResult(size_t jobsTotal, const Duration& duration)
{
boost::unique_lock<boost::mutex> dummy(lockResult);
return conditionJobDone.timed_wait(dummy, duration, [&] { return this->jobDone(jobsTotal); });
//use timed_wait predicate if exitting before condition is reached: http://www.boost.org/doc/libs/1_49_0/doc/html/thread/synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait_rel
}
std::unique_ptr<T> getResult(size_t jobsTotal)
{
boost::unique_lock<boost::mutex> dummy(lockResult);
while (!jobDone(jobsTotal))
conditionJobDone.timed_wait(dummy, boost::posix_time::milliseconds(50)); //interruption point!
#ifndef NDEBUG
assert(!returnedResult);
returnedResult = true;
#endif
return std::move(result_);
}
private:
bool jobDone(size_t jobsTotal) const { return result_ || (jobsFinished >= jobsTotal); } //call while locked!
#ifndef NDEBUG
bool returnedResult;
#endif
boost::mutex lockResult;
size_t jobsFinished; //
std::unique_ptr<T> result_; //our condition is: "have result" or "jobsFinished == jobsTotal"
boost::condition_variable conditionJobDone;
};
template <class T> inline
RunUntilFirstHit<T>::RunUntilFirstHit() : result(std::make_shared<AsyncResult>()), jobsTotal(0) {}
template <class T>
template <class Fun> inline
void RunUntilFirstHit<T>::addJob(Fun f) //f must return a std::unique_ptr<T> containing a value on success
{
auto result2 = result; //MSVC2010: this is ridiculous!!!
boost::thread t([result2, f] { result2->reportFinished(f()); });
++jobsTotal;
t.detach(); //we have to be explicit since C++11: [thread.thread.destr] ~thread() calls std::terminate() if joinable()!!!
}
template <class T>
template <class Duration> inline
bool RunUntilFirstHit<T>::timedWait(const Duration& duration) const { return result->waitForResult(jobsTotal, duration); }
template <class T> inline
std::unique_ptr<T> RunUntilFirstHit<T>::get() const { return result->getResult(jobsTotal); }
}
#endif //BOOST_THREAD_WRAP_H
|
