Chris@297: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@297: 
Chris@297: /*
Chris@297:     Sonic Visualiser
Chris@297:     An audio file viewer and annotation editor.
Chris@297:     Centre for Digital Music, Queen Mary, University of London.
Chris@297:     This file copyright 2007 QMUL.
Chris@297:     
Chris@297:     This program is free software; you can redistribute it and/or
Chris@297:     modify it under the terms of the GNU General Public License as
Chris@297:     published by the Free Software Foundation; either version 2 of the
Chris@297:     License, or (at your option) any later version.  See the file
Chris@297:     COPYING included with this distribution for more information.
Chris@297: */
Chris@297: 
Chris@297: #include "Serialiser.h"
Chris@1857: #include "Debug.h"
Chris@297: 
Chris@406: #include <iostream>
Chris@406: 
Chris@297: QMutex
Chris@297: Serialiser::m_mapMutex;
Chris@297: 
Chris@297: std::map<QString, QMutex *>
Chris@297: Serialiser::m_mutexMap;
Chris@297: 
Chris@297: Serialiser::Serialiser(QString id) :
Chris@1857:     Serialiser(id, nullptr) { }
Chris@1857: 
Chris@1857: Serialiser::Serialiser(QString id, const std::atomic<bool> *cancelled) :
Chris@1857:     m_id(id),
Chris@1857:     m_cancelled(cancelled),
Chris@1857:     m_locked(false)
Chris@297: {
Chris@297:     m_mapMutex.lock();
Chris@297:     
Chris@297:     if (m_mutexMap.find(m_id) == m_mutexMap.end()) {
Chris@297:         m_mutexMap[m_id] = new QMutex;
Chris@297:     }
Chris@297: 
Chris@406:     // The id mutexes are never deleted, so once we have a reference
Chris@406:     // to the one we need, we can hold on to it while we release the
Chris@406:     // map mutex.  We need to release the map mutex, otherwise if the
Chris@406:     // id mutex is currently held, it will never be released (because
Chris@406:     // the destructor needs to hold the map mutex to release the id
Chris@406:     // mutex).
Chris@406: 
Chris@406:     QMutex *idMutex = m_mutexMap[m_id];
Chris@398: 
Chris@297:     m_mapMutex.unlock();
Chris@406: 
Chris@1857:     if (!m_cancelled) {
Chris@1857:         idMutex->lock();
Chris@1857:         m_locked = true;
Chris@1857:     } else {
Chris@1857:         // try to lock, polling the cancelled status occasionally
Chris@1857:         while (!m_locked && ! *m_cancelled) {
Chris@1857:             m_locked = idMutex->tryLock(500);
Chris@1857:             if (*m_cancelled) {
Chris@1857:                 SVCERR << "Serialiser: cancelled!" << endl;
Chris@1857:             }
Chris@1857:         }
Chris@1857:     }
Chris@297: }
Chris@297: 
Chris@297: Serialiser::~Serialiser()
Chris@297: {
Chris@398:     m_mapMutex.lock();
Chris@1857: 
Chris@1857:     if (m_locked) {
Chris@1857:         m_mutexMap[m_id]->unlock();
Chris@1857:     }
Chris@398: 
Chris@398:     m_mapMutex.unlock();
Chris@297: }
Chris@297: 
Chris@297: 
Chris@297: