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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
Sonic Visualiser
An audio file viewer and annotation editor.
Centre for Digital Music, Queen Mary, University of London.
This file copyright 2007 QMUL.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version. See the file
COPYING included with this distribution for more information.
*/
#include "Serialiser.h"
#include "Debug.h"
#include <iostream>
namespace sv {
QMutex
Serialiser::m_mapMutex;
std::map<QString, QMutex *>
Serialiser::m_mutexMap;
Serialiser::Serialiser(QString id) :
Serialiser(id, nullptr) { }
Serialiser::Serialiser(QString id, const std::atomic<bool> *cancelled) :
m_id(id),
m_cancelled(cancelled),
m_locked(false)
{
m_mapMutex.lock();
if (m_mutexMap.find(m_id) == m_mutexMap.end()) {
m_mutexMap[m_id] = new QMutex;
}
// The id mutexes are never deleted, so once we have a reference
// to the one we need, we can hold on to it while we release the
// map mutex. We need to release the map mutex, otherwise if the
// id mutex is currently held, it will never be released (because
// the destructor needs to hold the map mutex to release the id
// mutex).
QMutex *idMutex = m_mutexMap[m_id];
m_mapMutex.unlock();
if (!m_cancelled) {
idMutex->lock();
m_locked = true;
} else {
// try to lock, polling the cancelled status occasionally
while (!m_locked && ! *m_cancelled) {
m_locked = idMutex->tryLock(500);
if (*m_cancelled) {
SVCERR << "Serialiser: cancelled!" << endl;
}
}
}
}
Serialiser::~Serialiser()
{
m_mapMutex.lock();
if (m_locked) {
m_mutexMap[m_id]->unlock();
}
m_mapMutex.unlock();
}
} // end namespace sv
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