Mercurial > hg > svcore
view base/Scavenger.h @ 1483:7459f4c4d7c3
Merge from branch plugin-path-config
author | Chris Cannam |
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date | Mon, 11 Jun 2018 14:40:09 +0100 |
parents | 48e9f538e6e9 |
children | ad5f892c0c4d |
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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 2006 Chris Cannam. 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. */ /* This is a modified version of a source file from the Rosegarden MIDI and audio sequencer and notation editor. This file copyright 2000-2006 Chris Cannam. */ #ifndef _SCAVENGER_H_ #define _SCAVENGER_H_ #include "system/System.h" #include <vector> #include <list> #include <QMutex> #include <iostream> /** * A very simple class that facilitates running things like plugins * without locking, by collecting unwanted objects and deleting them * after a delay so as to be sure nobody's in the middle of using * them. Requires scavenge() to be called regularly from a non-RT * thread. * * This is currently not at all suitable for large numbers of objects * -- it's just a quick hack for use with things like plugins. */ template <typename T> class Scavenger { public: Scavenger(int sec = 2, int defaultObjectListSize = 200); ~Scavenger(); /** * Call from an RT thread etc., to pass ownership of t to us. * Only one thread should be calling this on any given scavenger. */ void claim(T *t); /** * Call from a non-RT thread. * Only one thread should be calling this on any given scavenger. */ void scavenge(bool clearNow = false); protected: typedef std::pair<T *, time_t> ObjectTimePair; typedef std::vector<ObjectTimePair> ObjectTimeList; ObjectTimeList m_objects; time_t m_sec; typedef std::list<T *> ObjectList; ObjectList m_excess; time_t m_lastExcess; QMutex m_excessMutex; void pushExcess(T *); void clearExcess(time_t); unsigned int m_claimed; unsigned int m_scavenged; }; /** * A wrapper to permit arrays to be scavenged. */ template <typename T> class ScavengerArrayWrapper { public: ScavengerArrayWrapper(T *array) : m_array(array) { } ~ScavengerArrayWrapper() { delete[] m_array; } private: T *m_array; }; template <typename T> Scavenger<T>::Scavenger(int sec, int defaultObjectListSize) : m_objects(ObjectTimeList(defaultObjectListSize)), m_sec(sec), m_lastExcess(0), m_claimed(0), m_scavenged(0) { } template <typename T> Scavenger<T>::~Scavenger() { if (m_scavenged < m_claimed) { for (size_t i = 0; i < m_objects.size(); ++i) { ObjectTimePair &pair = m_objects[i]; if (pair.first != 0) { T *ot = pair.first; pair.first = 0; delete ot; ++m_scavenged; } } } clearExcess(0); } template <typename T> void Scavenger<T>::claim(T *t) { // std::cerr << "Scavenger::claim(" << t << ")" << std::endl; struct timeval tv; (void)gettimeofday(&tv, 0); time_t sec = tv.tv_sec; for (size_t i = 0; i < m_objects.size(); ++i) { ObjectTimePair &pair = m_objects[i]; if (pair.first == 0) { pair.second = sec; pair.first = t; ++m_claimed; return; } } std::cerr << "WARNING: Scavenger::claim(" << t << "): run out of slots, " << "using non-RT-safe method" << std::endl; pushExcess(t); } template <typename T> void Scavenger<T>::scavenge(bool clearNow) { // std::cerr << "Scavenger::scavenge: scavenged " << m_scavenged << ", claimed " << m_claimed << std::endl; if (m_scavenged >= m_claimed) return; struct timeval tv; (void)gettimeofday(&tv, 0); time_t sec = tv.tv_sec; for (size_t i = 0; i < m_objects.size(); ++i) { ObjectTimePair &pair = m_objects[i]; if (clearNow || (pair.first != 0 && pair.second + m_sec < sec)) { T *ot = pair.first; pair.first = 0; delete ot; ++m_scavenged; } } if (sec > m_lastExcess + m_sec) { clearExcess(sec); } } template <typename T> void Scavenger<T>::pushExcess(T *t) { m_excessMutex.lock(); m_excess.push_back(t); struct timeval tv; (void)gettimeofday(&tv, 0); m_lastExcess = tv.tv_sec; m_excessMutex.unlock(); } template <typename T> void Scavenger<T>::clearExcess(time_t sec) { m_excessMutex.lock(); for (typename ObjectList::iterator i = m_excess.begin(); i != m_excess.end(); ++i) { delete *i; } m_excess.clear(); m_lastExcess = sec; m_excessMutex.unlock(); } #endif