mutex.cpp
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// 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/mutex.hpp"
#include <algorithm>
#include <functional>
#include <system_error>
#include "boost/fiber/exceptions.hpp"
#include "boost/fiber/scheduler.hpp"
#include "boost/fiber/waker.hpp"
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_PREFIX
#endif
namespace boost {
namespace fibers {
void
mutex::lock() {
while ( true) {
context * active_ctx = context::active();
// store this fiber in order to be notified later
detail::spinlock_lock lk{ wait_queue_splk_ };
if ( BOOST_UNLIKELY( active_ctx == owner_) ) {
throw lock_error{
std::make_error_code( std::errc::resource_deadlock_would_occur),
"boost fiber: a deadlock is detected" };
}
if ( nullptr == owner_) {
owner_ = active_ctx;
return;
}
wait_queue_.suspend_and_wait( lk, active_ctx);
}
}
bool
mutex::try_lock() {
context * active_ctx = context::active();
detail::spinlock_lock lk{ wait_queue_splk_ };
if ( BOOST_UNLIKELY( active_ctx == owner_) ) {
throw lock_error{
std::make_error_code( std::errc::resource_deadlock_would_occur),
"boost fiber: a deadlock is detected" };
}
if ( nullptr == owner_) {
owner_ = active_ctx;
}
lk.unlock();
// let other fiber release the lock
active_ctx->yield();
return active_ctx == owner_;
}
void
mutex::unlock() {
context * active_ctx = context::active();
detail::spinlock_lock lk{ wait_queue_splk_ };
if ( BOOST_UNLIKELY( active_ctx != owner_) ) {
throw lock_error{
std::make_error_code( std::errc::operation_not_permitted),
"boost fiber: no privilege to perform the operation" };
}
owner_ = nullptr;
wait_queue_.notify_one();
}
}}
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_SUFFIX
#endif