95 lines
2.1 KiB
C++
95 lines
2.1 KiB
C++
/*
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* Copyright 2003-2017 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include "Call.hxx"
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#include "Loop.hxx"
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#include "DeferEvent.hxx"
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#include "thread/Mutex.hxx"
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#include "thread/Cond.hxx"
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#include "util/Compiler.h"
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#include <exception>
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#include <assert.h>
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class BlockingCallMonitor final
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{
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DeferEvent defer_event;
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const std::function<void()> f;
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Mutex mutex;
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Cond cond;
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bool done;
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std::exception_ptr exception;
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public:
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BlockingCallMonitor(EventLoop &_loop, std::function<void()> &&_f)
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:defer_event(_loop, BIND_THIS_METHOD(RunDeferred)),
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f(std::move(_f)), done(false) {}
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void Run() {
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assert(!done);
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defer_event.Schedule();
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mutex.lock();
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while (!done)
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cond.wait(mutex);
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mutex.unlock();
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if (exception)
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std::rethrow_exception(exception);
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}
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private:
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void RunDeferred() noexcept {
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assert(!done);
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try {
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f();
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} catch (...) {
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exception = std::current_exception();
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}
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mutex.lock();
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done = true;
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cond.signal();
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mutex.unlock();
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}
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};
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void
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BlockingCall(EventLoop &loop, std::function<void()> &&f)
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{
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if (loop.IsDead() || loop.IsInside()) {
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/* we're already inside the loop - we can simply call
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the function */
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f();
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} else {
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/* outside the EventLoop's thread - defer execution to
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the EventLoop, wait for completion */
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BlockingCallMonitor m(loop, std::move(f));
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m.Run();
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}
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}
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