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Files
fiber/src/timed_mutex.cpp
2015-12-03 17:57:00 +01:00

103 lines
2.7 KiB
C++

// Copyright Oliver Kowalke 2013.
// 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)
#include "boost/fiber/timed_mutex.hpp"
#include <algorithm>
#include <functional>
#include "boost/fiber/exceptions.hpp"
#include "boost/fiber/scheduler.hpp"
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_PREFIX
#endif
namespace boost {
namespace fibers {
bool
timed_mutex::try_lock_until_( std::chrono::steady_clock::time_point const& timeout_time) noexcept {
if ( std::chrono::steady_clock::now() > timeout_time) {
return false;
}
context * ctx = context::active();
// store this fiber in order to be notified later
detail::spinlock_lock lk( wait_queue_splk_);
if ( nullptr == owner_) {
owner_ = ctx;
return true;
}
BOOST_ASSERT( ! ctx->wait_is_linked() );
ctx->wait_link( wait_queue_);
// suspend this fiber until notified or timed-out
if ( ! context::active()->wait_until( timeout_time, lk) ) {
// remove fiber from wait-queue
lk.lock();
ctx->wait_unlink();
return false;
}
BOOST_ASSERT( ! ctx->wait_is_linked() );
return true;
}
void
timed_mutex::lock() {
context * ctx = context::active();
// store this fiber in order to be notified later
detail::spinlock_lock lk( wait_queue_splk_);
if ( ctx == owner_) {
throw lock_error( static_cast< int >( std::errc::resource_deadlock_would_occur),
"boost fiber: a deadlock is detected");
} else if ( nullptr == owner_) {
owner_ = ctx;
return;
}
BOOST_ASSERT( ! ctx->wait_is_linked() );
ctx->wait_link( wait_queue_);
// suspend this fiber
ctx->suspend( lk);
BOOST_ASSERT( ! ctx->wait_is_linked() );
}
bool
timed_mutex::try_lock() noexcept {
context * ctx = context::active();
detail::spinlock_lock lk( wait_queue_splk_);
if ( nullptr == owner_) {
owner_ = ctx;
}
lk.unlock();
// let other fiber release the lock
context::active()->yield();
return ctx == owner_;
}
void
timed_mutex::unlock() {
context * ctx = context::active();
detail::spinlock_lock lk( wait_queue_splk_);
if ( ctx != owner_) {
throw lock_error( static_cast< int >( std::errc::operation_not_permitted),
"boost fiber: no privilege to perform the operation");
}
if ( ! wait_queue_.empty() ) {
context * ctx = & wait_queue_.front();
wait_queue_.pop_front();
owner_ = ctx;
context::active()->set_ready( ctx);
} else {
owner_ = nullptr;
return;
}
}
}}
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_SUFFIX
#endif