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// Copyright (c) 2017-2022, 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.
#pragma once
#include <boost/thread/condition_variable.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/thread.hpp>
#include <cstddef>
#include <functional>
#include <utility>
#include <vector>
#include <stdexcept>
namespace tools
{
//! A global thread pool
class threadpool
{
public:
static threadpool& getInstance() {
static threadpool instance;
return instance;
}
static threadpool *getNewForUnitTests(unsigned max_threads = 0) {
return new threadpool(max_threads);
}
// The waiter lets the caller know when all of its
// tasks are completed.
class waiter {
boost::mutex mt;
boost::condition_variable cv;
threadpool &pool;
int num;
bool error_flag;
public:
void inc();
void dec();
bool wait(); //! Wait for a set of tasks to finish, returns false iff any error
void set_error() noexcept { error_flag = true; }
bool error() const noexcept { return error_flag; }
waiter(threadpool &pool) : pool(pool), num(0), error_flag(false) {}
~waiter();
};
// Submit a task to the pool. The waiter pointer may be
// NULL if the caller doesn't care to wait for the
// task to finish.
void submit(waiter *waiter, std::function<void()> f, bool leaf = false);
// destroy and recreate threads
void recycle();
unsigned int get_max_concurrency() const;
~threadpool();
private:
threadpool(unsigned int max_threads = 0);
void destroy();
void create(unsigned int max_threads);
typedef struct entry {
waiter *wo;
std::function<void()> f;
bool leaf;
} entry;
std::deque<entry> queue;
boost::condition_variable has_work;
boost::mutex mutex;
std::vector<boost::thread> threads;
unsigned int active;
unsigned int max;
bool running;
void run(bool flush = false);
};
}
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