src/DiskIO/AIO/AIODiskIOStrategy.h

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