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// Copyright (c) 2014-2016, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "common/task_region.h"
#include <boost/thread/locks.hpp>
#include <cassert>
/* `mark_completed` and `wait` can throw in the lock call, but its difficult to
recover from either. An exception in `wait` means the post condition of joining
all threads cannot be achieved, and an exception in `mark_completed` means
certain deadlock. `noexcept` qualifier will force a call to `std::terminate` if
locking throws an exception, which should only happen if a recursive lock
attempt is made (which is not possible since no external function is called
while holding the lock). */
namespace tools
{
void task_region_handle::state::mark_completed(id task_id) noexcept {
assert(task_id != 0 && (task_id & (task_id - 1)) == 0); // power of 2 check
if (pending.fetch_and(~task_id) == task_id) {
// synchronize with wait call, but do not need to hold
boost::unique_lock<boost::mutex>{sync_on_complete};
all_complete.notify_all();
}
}
void task_region_handle::state::abort() noexcept {
state* current = this;
while (current) {
current->ready = 0;
current = current->next.get();
}
}
void task_region_handle::state::wait() noexcept {
state* current = this;
while (current) {
{
boost::unique_lock<boost::mutex> lock{current->sync_on_complete};
current->all_complete.wait(lock, [current] { return current->pending == 0; });
}
current = current->next.get();
}
}
void task_region_handle::state::wait(thread_group& threads) noexcept {
state* current = this;
while (current) {
while (current->pending != 0) {
if (!threads.try_run_one()) {
current->wait();
return;
}
}
current = current->next.get();
}
}
void task_region_handle::create_state() {
st = std::make_shared<state>(std::move(st));
next_id = 1;
}
void task_region_handle::do_wait() noexcept {
assert(st);
const std::shared_ptr<state> temp = std::move(st);
temp->wait(threads);
}
}
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