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130 lines
2.7 KiB
C++
130 lines
2.7 KiB
C++
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// Copyright Oliver Kowalke 2013.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include "boost/fiber/mutex.hpp"
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#include <algorithm>
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#include <boost/assert.hpp>
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#include "boost/fiber/detail/main_notifier.hpp"
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#include "boost/fiber/detail/scheduler.hpp"
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#include "boost/fiber/interruption.hpp"
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#include "boost/fiber/operations.hpp"
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#ifdef BOOST_HAS_ABI_HEADERS
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# include BOOST_ABI_PREFIX
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#endif
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namespace boost {
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namespace fibers {
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mutex::mutex() :
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owner_(),
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state_( UNLOCKED),
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splk_(),
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waiting_()
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{}
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mutex::~mutex()
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{
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BOOST_ASSERT( ! owner_);
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BOOST_ASSERT( waiting_.empty() );
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}
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void
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mutex::lock()
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{
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detail::notify::ptr_t n( detail::scheduler::instance()->active() );
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if ( n)
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{
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for (;;)
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{
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unique_lock< detail::spinlock > lk( splk_);
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state_t expected = UNLOCKED;
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if ( state_.compare_exchange_strong( expected, LOCKED) )
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break;
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// store this fiber in order to be notified later
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waiting_.push_back( n);
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// suspend this fiber
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detail::scheduler::instance()->wait( lk);
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}
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}
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else
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{
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// notifier for main-fiber
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detail::main_notifier mn;
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n = detail::main_notifier::make_pointer( mn);
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for (;;)
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{
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unique_lock< detail::spinlock > lk( splk_);
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state_t expected = UNLOCKED;
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if ( state_.compare_exchange_strong( expected, LOCKED) )
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break;
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// store this fiber in order to be notified later
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waiting_.push_back( n);
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lk.unlock();
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// wait until main-fiber gets notified
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while ( ! n->is_ready() )
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{
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// run scheduler
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detail::scheduler::instance()->run();
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}
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}
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}
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BOOST_ASSERT( ! owner_);
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owner_ = this_fiber::get_id();
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}
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bool
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mutex::try_lock()
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{
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state_t expected = UNLOCKED;
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if ( ! state_.compare_exchange_strong( expected, LOCKED) ) {
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// let other fiber release the lock
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detail::scheduler::instance()->yield();
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return false;
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}
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owner_ = this_fiber::get_id();
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return true;
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}
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void
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mutex::unlock()
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{
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BOOST_ASSERT( LOCKED == state_);
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BOOST_ASSERT( this_fiber::get_id() == owner_);
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detail::notify::ptr_t n;
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unique_lock< detail::spinlock > lk( splk_);
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if ( ! waiting_.empty() ) {
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n.swap( waiting_.front() );
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waiting_.pop_front();
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}
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owner_ = detail::fiber_base::id();
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state_ = UNLOCKED;
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if ( n) n->set_ready();
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}
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}}
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#ifdef BOOST_HAS_ABI_HEADERS
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# include BOOST_ABI_SUFFIX
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#endif
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