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
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
|
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// (C) Copyright 2013 Vicente J. Botet Escriba
#ifndef BOOST_THREAD_COMPLETION_LATCH_HPP
#define BOOST_THREAD_COMPLETION_LATCH_HPP
#include <boost/thread/detail/config.hpp>
#include <boost/thread/detail/delete.hpp>
#include <boost/thread/detail/counter.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/lock_types.hpp>
#include <boost/thread/condition_variable.hpp>
#include <boost/chrono/duration.hpp>
#include <boost/chrono/time_point.hpp>
#include <boost/assert.hpp>
//#include <boost/thread/detail/nullary_function.hpp>
#include <boost/thread/csbl/functional.hpp>
#include <boost/config/abi_prefix.hpp>
namespace boost
{
namespace thread_detail
{
void noop()
{
}
}
class completion_latch
{
public:
/// the implementation defined completion function type
//typedef detail::nullary_function<void()> completion_function;
typedef csbl::function<void()> completion_function;
/// noop completion function factory
static completion_function noop()
{
return completion_function(&thread_detail::noop);
}
private:
struct around_wait;
friend struct around_wait;
struct around_wait
{
completion_latch &that_;
boost::unique_lock<boost::mutex> &lk_;
around_wait(completion_latch &that, boost::unique_lock<boost::mutex> &lk)
: that_(that), lk_(lk)
{
that_.leavers_.cond_.wait(lk, detail::counter_is_zero(that_.leavers_));
that_.waiters_.inc_and_notify_all();
that_.leavers_.cond_.wait(lk, detail::counter_is_not_zero(that_.leavers_));
}
~around_wait()
{
that_.waiters_.dec_and_notify_all();
}
};
bool count_down(unique_lock<mutex> &lk)
{
BOOST_ASSERT(count_ > 0);
if (--count_ == 0)
{
waiters_.cond_.wait(lk, detail::counter_is_not_zero(waiters_));
leavers_.assign_and_notify_all(waiters_);
count_.cond_.notify_all();
waiters_.cond_.wait(lk, detail::counter_is_zero(waiters_));
leavers_.assign_and_notify_all(0);
lk.unlock();
funct_();
return true;
}
return false;
}
public:
BOOST_THREAD_NO_COPYABLE( completion_latch )
/// Constructs a latch with a given count.
completion_latch(std::size_t count) :
count_(count), funct_(noop()), waiters_(0), leavers_(0)
{
}
/// Constructs a latch with a given count and a completion function.
template <typename F>
completion_latch(std::size_t count, BOOST_THREAD_RV_REF(F) funct) :
count_(count),
funct_(boost::move(funct)),
waiters_(0),
leavers_(0)
{
}
completion_latch(std::size_t count, void(*funct)()) :
count_(count), funct_(funct), waiters_(0), leavers_(0)
{
}
///
~completion_latch()
{
}
/// Blocks until the latch has counted down to zero.
void wait()
{
boost::unique_lock<boost::mutex> lk(mutex_);
around_wait aw(*this, lk);
count_.cond_.wait(lk, detail::counter_is_zero(count_));
}
/// @return true if the internal counter is already 0, false otherwise
bool try_wait()
{
boost::unique_lock<boost::mutex> lk(mutex_);
around_wait aw(*this, lk);
return (count_ == 0);
}
/// try to wait for a specified amount of time
/// @return whether there is a timeout or not.
template <class Rep, class Period>
cv_status wait_for(const chrono::duration<Rep, Period>& rel_time)
{
boost::unique_lock<boost::mutex> lk(mutex_);
around_wait aw(*this, lk);
return count_.cond_.wait_for(lk, rel_time, detail::counter_is_zero(count_))
? cv_status::no_timeout
: cv_status::timeout;
}
/// try to wait until the specified time_point is reached
/// @return whether there is a timeout or not.
template <class Clock, class Duration>
cv_status wait_until(const chrono::time_point<Clock, Duration>& abs_time)
{
boost::unique_lock<boost::mutex> lk(mutex_);
around_wait aw(*this, lk);
return count_.cond_.wait_until(lk, abs_time, detail::counter_is_zero(count_))
? cv_status::no_timeout
: cv_status::timeout;
}
/// Decrement the count and notify anyone waiting if we reach zero.
/// @Requires count must be greater than 0
void count_down()
{
unique_lock<mutex> lk(mutex_);
count_down(lk);
}
void signal()
{
count_down();
}
/// Decrement the count and notify anyone waiting if we reach zero.
/// Blocks until the latch has counted down to zero.
/// @Requires count must be greater than 0
void count_down_and_wait()
{
boost::unique_lock<boost::mutex> lk(mutex_);
if (count_down(lk))
{
return;
}
around_wait aw(*this, lk);
count_.cond_.wait(lk, detail::counter_is_zero(count_));
}
void sync()
{
count_down_and_wait();
}
/// Reset the counter
/// #Requires This method may only be invoked when there are no other threads currently inside the count_down_and_wait() method.
void reset(std::size_t count)
{
boost::lock_guard<boost::mutex> lk(mutex_);
//BOOST_ASSERT(count_ == 0);
count_ = count;
}
/// Resets the latch with the new completion function.
/// The next time the internal count reaches 0, this function will be invoked.
/// This completion function may only be invoked when there are no other threads
/// currently inside the count_down and wait related functions.
/// It may also be invoked from within the registered completion function.
/// @Returns the old completion function if any or noop if
#ifdef BOOST_NO_CXX11_HDR_FUNCTIONAL
template <typename F>
completion_function then(BOOST_THREAD_RV_REF(F) funct)
{
boost::lock_guard<boost::mutex> lk(mutex_);
completion_function tmp(funct_);
funct_ = boost::move(funct);
return tmp;
}
#endif
completion_function then(void(*funct)())
{
boost::lock_guard<boost::mutex> lk(mutex_);
completion_function tmp(funct_);
funct_ = completion_function(funct);
return tmp;
}
private:
mutex mutex_;
detail::counter count_;
completion_function funct_;
detail::counter waiters_;
detail::counter leavers_;
};
} // namespace boost
#include <boost/config/abi_suffix.hpp>
#endif
|
