src/DiskIO/AIO/AIODiskIOStrategy.h

   1
   2 /*
   3  * $Id$
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This program is free software; you can redistribute it and/or modify
  18  *  it under the terms of the GNU General Public License as published by
  19  *  the Free Software Foundation; either version 2 of the License, or
  20  *  (at your option) any later version.
  21  *
  22  *  This program is distributed in the hope that it will be useful,
  23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  *  GNU General Public License for more details.
  26  *
  27  *  You should have received a copy of the GNU General Public License
  28  *  along with this program; if not, write to the Free Software
  29  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  30  *
  31  * Copyright (c) 2003, Robert Collins <robertc@squid-cache.org>
  32  */
  33
  34 #ifndef SQUID_AIODISKIOSTRATEGY_H
  35 #define SQUID_AIODISKIOSTRATEGY_H
  36
  37 #include "DiskIO/DiskIOStrategy.h"
  38 #include "async_io.h"
  39
  40 class AIODiskIOStrategy : public DiskIOStrategy
  41 {
  42
  43 public:
  44     AIODiskIOStrategy();
  45     virtual ~AIODiskIOStrategy();
  46
  47     virtual bool shedLoad();
  48     /* What is the current load? 999 = 99.9% */
  49     virtual int load();
  50     /* Return a handle for performing IO operations */
  51     virtual RefCount<DiskFile> newFile (char const *path);
  52     /* flush all IO operations  */
  53     virtual void sync();
  54     /* unlink a file by path */
  55     virtual void unlinkFile (char const *);
  56
  57     /* perform any pending callbacks */
  58     virtual int callback();
  59
  60     /* Init per-instance logic */
  61     virtual void init();
  62
  63     /* cachemgr output on the IO instance stats */
  64     virtual void statfs(StoreEntry & sentry)const;
  65     /* module specific options */
  66     virtual ConfigOption *getOptionTree() const;
  67     /* a file descriptor */
  68     int fd;
  69     /* queue of requests */
  70     async_queue_t aq;
  71
  72     int findSlot();
  73 };
  74
  75 #endif /* SQUID_AIODISKIOSTRATEGY_H */