Aegisub/libaegisub/common/dispatch.cpp

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// Copyright (c) 2013, Thomas Goyne <plorkyeran@aegisub.org>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
// Aegisub Project http://www.aegisub.org/
#include "config.h"
#include "libaegisub/dispatch.h"
#include "libaegisub/util.h"
#include <atomic>
#include <boost/asio/io_service.hpp>
#include <boost/asio/strand.hpp>
#include <condition_variable>
#include <mutex>
#include <thread>
namespace {
boost::asio::io_service *service;
std::function<void (agi::dispatch::Thunk)> invoke_main;
std::atomic<uint_fast32_t> threads_running;
class MainQueue final : public agi::dispatch::Queue {
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void DoInvoke(agi::dispatch::Thunk thunk) override {
invoke_main(thunk);
}
};
class BackgroundQueue final : public agi::dispatch::Queue {
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void DoInvoke(agi::dispatch::Thunk thunk) override {
service->post(thunk);
}
};
class SerialQueue final : public agi::dispatch::Queue {
boost::asio::io_service::strand strand;
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void DoInvoke(agi::dispatch::Thunk thunk) override {
strand.post(thunk);
}
public:
SerialQueue() : strand(*service) { }
};
struct IOServiceThreadPool {
boost::asio::io_service io_service;
std::unique_ptr<boost::asio::io_service::work> work;
std::vector<std::thread> threads;
IOServiceThreadPool() : work(new boost::asio::io_service::work(io_service)) { }
~IOServiceThreadPool() {
work.reset();
#ifndef _WIN32
for (auto& thread : threads) thread.join();
#else
// Calling join() after main() returns deadlocks
// https://connect.microsoft.com/VisualStudio/feedback/details/747145
for (auto& thread : threads) thread.detach();
while (threads_running) std::this_thread::yield();
#endif
}
};
}
namespace agi { namespace dispatch {
void Init(std::function<void (Thunk)> invoke_main) {
static IOServiceThreadPool thread_pool;
::service = &thread_pool.io_service;
::invoke_main = invoke_main;
thread_pool.threads.reserve(std::max<unsigned>(4, std::thread::hardware_concurrency()));
for (size_t i = 0; i < thread_pool.threads.capacity(); ++i) {
thread_pool.threads.emplace_back([]{
++threads_running;
agi::util::SetThreadName("Dispatch Worker");
service->run();
--threads_running;
});
}
}
void Queue::Async(Thunk thunk) {
DoInvoke(thunk);
}
void Queue::Sync(Thunk thunk) {
std::mutex m;
std::condition_variable cv;
std::unique_lock<std::mutex> l(m);
bool done = false;
DoInvoke([&]{
std::unique_lock<std::mutex> l(m);
thunk();
done = true;
cv.notify_all();
});
cv.wait(l, [&]{ return done; });
}
Queue& Main() {
static MainQueue q;
return q;
}
Queue& Background() {
static BackgroundQueue q;
return q;
}
std::unique_ptr<Queue> Create() {
return std::unique_ptr<Queue>(new SerialQueue);
}
} }