disk_queues.h

/***************************************************************************
 * include/stxxl/bits/io/disk_queues.h
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 * Copyright (C) 2008-2010 Andreas Beckmann <[email protected]>
 * Copyright (C) 2009 Johannes Singler <[email protected]>
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/

#ifndef STXXL_IO_DISK_QUEUES_HEADER
#define STXXL_IO_DISK_QUEUES_HEADER

#include <map>

#include <stxxl/bits/namespace.h>
#include <stxxl/bits/singleton.h>
#include <stxxl/bits/io/iostats.h>
#include <stxxl/bits/io/request_queue_impl_qwqr.h>


__STXXL_BEGIN_NAMESPACE


class request_ptr;

class disk_queues : public singleton<disk_queues>
{
 friend class singleton<disk_queues>;

 // 2 queues: write queue and read queue
 typedef request_queue_impl_qwqr request_queue_type;

 typedef stxxl::int64 DISKID;
 typedef std::map<DISKID, request_queue_type *> request_queue_map;

protected:
 request_queue_map queues;
 disk_queues()
 {
 stxxl::stats::get_instance(); // initialize stats before ourselves
 }

public:
 void add_request(request_ptr & req, DISKID disk)
 {
#ifdef STXXL_HACK_SINGLE_IO_THREAD
 disk = 42;
#endif
 if (queues.find(disk) == queues.end())
 {
 // create new request queue
 queues[disk] = new request_queue_type();
 }
 queues[disk]->add_request(req);
 }

 bool cancel_request(request_ptr & req, DISKID disk)
 {
#ifdef STXXL_HACK_SINGLE_IO_THREAD
 disk = 42;
#endif
 if (queues.find(disk) != queues.end())
 return queues[disk]->cancel_request(req);
 else
 return false;
 }

 ~disk_queues()
 {
 // deallocate all queues
 for (request_queue_map::iterator i = queues.begin(); i != queues.end(); i++)
 delete (*i).second;
 }

 void set_priority_op(request_queue::priority_op op)
 {
 for (request_queue_map::iterator i = queues.begin(); i != queues.end(); i++)
 i->second->set_priority_op(op);
 }
};


__STXXL_END_NAMESPACE

#endif // !STXXL_IO_DISK_QUEUES_HEADER
// vim: et:ts=4:sw=4