src/DiskIO/AIO/AIODiskIOStrategy.h

   1 /*
   2  * $Id$
   3  *
   4  * SQUID Web Proxy Cache          http://www.squid-cache.org/
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   7  *  Squid is the result of efforts by numerous individuals from
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  10  *  development; see the SPONSORS file for full details.  Squid is
  11  *  Copyrighted (C) 2001 by the Regents of the University of
  12  *  California; see the COPYRIGHT file for full details.  Squid
  13  *  incorporates software developed and/or copyrighted by other
  14  *  sources; see the CREDITS file for full details.
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License as published by
  18  *  the Free Software Foundation; either version 2 of the License, or
  19  *  (at your option) any later version.
  20  *
  21  *  This program is distributed in the hope that it will be useful,
  22  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *  GNU General Public License for more details.
  25  *
  26  *  You should have received a copy of the GNU General Public License
  27  *  along with this program; if not, write to the Free Software
  28  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  29  *
  30  * Copyright (c) 2003, Robert Collins <robertc@squid-cache.org>
  31  */
  32
  33 #ifndef SQUID_AIODISKIOSTRATEGY_H
  34 #define SQUID_AIODISKIOSTRATEGY_H
  35
  36 #include "config.h"
  37
  38 #if USE_DISKIO_AIO
  39
  40 #include "DiskIO/DiskIOStrategy.h"
  41 #include "async_io.h"
  42
  43 class AIODiskIOStrategy : public DiskIOStrategy
  44 {
  45
  46 public:
  47     AIODiskIOStrategy();
  48     virtual ~AIODiskIOStrategy();
  49
  50     virtual bool shedLoad();
  51     /* What is the current load? 999 = 99.9% */
  52     virtual int load();
  53     /* Return a handle for performing IO operations */
  54     virtual RefCount<DiskFile> newFile (char const *path);
  55     /* flush all IO operations  */
  56     virtual void sync();
  57     /* unlink a file by path */
  58     virtual void unlinkFile (char const *);
  59
  60     /* perform any pending callbacks */
  61     virtual int callback();
  62
  63     /* Init per-instance logic */
  64     virtual void init();
  65
  66     /* cachemgr output on the IO instance stats */
  67     virtual void statfs(StoreEntry & sentry)const;
  68     /* module specific options */
  69     virtual ConfigOption *getOptionTree() const;
  70     /* a file descriptor */
  71     int fd;
  72     /* queue of requests */
  73     async_queue_t aq;
  74
  75     int findSlot();
  76 };
  77
  78 #endif /* USE_DISKIO_AIO */
  79 #endif /* SQUID_AIODISKIOSTRATEGY_H */