mirror of
https://github.com/boostorg/fiber.git
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f1ab9c738e
* remove context::wait_hook_ and context::twstatus in flavor to waker_epoch_ and waker class * this avoids data races in case of wait_until() operations, when the context could be timeouted and rescheduled on the other OS thread. In this case could be data races with context::wait_hook_ and inconsistences context::twstatus states. * using context::waker_epoch_ introduces mechanism when the old wakers become outdated and waker::wake() is just no op. This fixes data races explained in the previous point * fibers waiting queue with timeouts and notification mechanisms are incapsulated into wait_queue class. This introduces simple abstraction level to be used in different synchronization primitives
96 lines
2.6 KiB
C++
96 lines
2.6 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/timed_mutex.hpp"
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#include <algorithm>
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#include <functional>
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#include "boost/fiber/exceptions.hpp"
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#include "boost/fiber/scheduler.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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bool
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timed_mutex::try_lock_until_( std::chrono::steady_clock::time_point const& timeout_time) noexcept {
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while ( true) {
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if ( std::chrono::steady_clock::now() > timeout_time) {
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return false;
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}
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context * active_ctx = context::active();
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detail::spinlock_lock lk{ wait_queue_splk_ };
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if ( nullptr == owner_) {
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owner_ = active_ctx;
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return true;
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}
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if ( ! wait_queue_.suspend_and_wait_until( lk, active_ctx, timeout_time)) {
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return false;
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}
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}
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}
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void
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timed_mutex::lock() {
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while ( true) {
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context * active_ctx = context::active();
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// store this fiber in order to be notified later
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detail::spinlock_lock lk{ wait_queue_splk_ };
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if ( BOOST_UNLIKELY( active_ctx == owner_) ) {
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throw lock_error{
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std::make_error_code( std::errc::resource_deadlock_would_occur),
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"boost fiber: a deadlock is detected" };
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}
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if ( nullptr == owner_) {
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owner_ = active_ctx;
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return;
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}
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wait_queue_.suspend_and_wait( lk, active_ctx);
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}
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}
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bool
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timed_mutex::try_lock() {
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context * active_ctx = context::active();
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detail::spinlock_lock lk{ wait_queue_splk_ };
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if ( BOOST_UNLIKELY( active_ctx == owner_) ) {
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throw lock_error{
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std::make_error_code( std::errc::resource_deadlock_would_occur),
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"boost fiber: a deadlock is detected" };
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}
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if ( nullptr == owner_) {
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owner_ = active_ctx;
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}
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lk.unlock();
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// let other fiber release the lock
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active_ctx->yield();
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return active_ctx == owner_;
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}
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void
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timed_mutex::unlock() {
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context * active_ctx = context::active();
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detail::spinlock_lock lk{ wait_queue_splk_ };
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if ( BOOST_UNLIKELY( active_ctx != owner_) ) {
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throw lock_error{
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std::make_error_code( std::errc::operation_not_permitted),
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"boost fiber: no privilege to perform the operation" };
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}
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owner_ = nullptr;
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wait_queue_.notify_one();
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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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