/usr/include/boost/thread/latch.hpp is in libboost1.54-dev 1.54.0-4ubuntu3.
This file is owned by root:root, with mode 0o644.
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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 | // 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_LATCH_HPP
#define BOOST_THREAD_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/config/abi_prefix.hpp>
namespace boost
{
class latch
{
/// @Requires: count_.value_ must be greater than 0
/// Effect: Decrement the count. Unlocks the lock notify anyone waiting if we reached zero.
/// Returns: true if count_.value_ reached the value 0.
/// @ThreadSafe ensured by the @c lk parameter
bool count_down(unique_lock<mutex> &lk)
/// pre_condition (count_.value_ > 0)
{
BOOST_ASSERT(count_.value_ > 0);
if (--count_.value_ == 0)
{
count_.cond_.notify_all();
lk.unlock();
return true;
}
return false;
}
public:
BOOST_THREAD_NO_COPYABLE( latch)
/// Constructs a latch with a given count.
latch(std::size_t count) :
count_(count)
{
}
/// Destructor
/// Precondition: No threads are waiting or invoking count_down on @c *this.
~latch()
{
}
/// Blocks until the latch has counted down to zero.
void wait()
{
boost::unique_lock<boost::mutex> lk(mutex_);
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_);
return (count_ == 0);
}
/// try to wait for a specified amount of time is elapsed.
/// @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_);
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 were 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_);
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()
{
boost::unique_lock<boost::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;
}
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;
}
private:
mutex mutex_;
detail::counter count_;
};
} // namespace boost
#include <boost/config/abi_suffix.hpp>
#endif
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