src/fs/ufs/UFSStoreState.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_FS_UFS_UFSSTORESTATE_H
  10 #define SQUID_FS_UFS_UFSSTORESTATE_H
  11
  12 #include "DiskIO/IORequestor.h"
  13 #include "SquidList.h"
  14 #include "StoreIOState.h"
  15
  16 namespace Fs
  17 {
  18 namespace Ufs
  19 {
  20
  21 class UFSStoreState : public StoreIOState, public IORequestor
  22 {
  23     CBDATA_CLASS(UFSStoreState);
  24
  25 public:
  26     UFSStoreState(SwapDir * SD, StoreEntry * anEntry, STIOCB * callback_, void *callback_data_);
  27     ~UFSStoreState();
  28     virtual void close(int how);
  29     virtual void closeCompleted();
  30     // protected:
  31     virtual void ioCompletedNotification();
  32     virtual void readCompleted(const char *buf, int len, int errflag, RefCount<ReadRequest>);
  33     virtual void writeCompleted(int errflag, size_t len, RefCount<WriteRequest>);
  34     RefCount<DiskFile> theFile;
  35     bool opening;
  36     bool creating;
  37     bool closing;
  38     bool reading;
  39     bool writing;
  40     /* StoreIOState API */
  41     void read_(char *buf, size_t size, off_t offset, STRCB * callback, void *callback_data);
  42     virtual bool write(char const *buf, size_t size, off_t offset, FREE * free_func);
  43
  44 protected:
  45     virtual void doCloseCallback (int errflag);
  46
  47     class _queued_read
  48     {
  49         MEMPROXY_CLASS(UFSStoreState::_queued_read);
  50     public:
  51         _queued_read() : buf(NULL), size(0), offset(0), callback(NULL), callback_data(NULL) {}
  52
  53         char *buf;
  54         size_t size;
  55         off_t offset;
  56         STRCB *callback;
  57         void *callback_data;
  58     };
  59
  60     class _queued_write
  61     {
  62         MEMPROXY_CLASS(UFSStoreState::_queued_write);
  63     public:
  64         _queued_write() : buf(NULL), size(0), offset(0), free_func(NULL) {}
  65
  66         char const *buf;
  67         size_t size;
  68         off_t offset;
  69         FREE *free_func;
  70     };
  71
  72     /** \todo These should be in the IO strategy */
  73
  74     struct {
  75         /**
  76          * DPW 2006-05-24
  77          * the write_draining flag is used to avoid recursion inside
  78          * the UFSStoreState::drainWriteQueue() method.
  79          */
  80         bool write_draining;
  81         /**
  82          * DPW 2006-05-24
  83          * The try_closing flag is set by UFSStoreState::tryClosing()
  84          * when UFSStoreState wants to close the file, but cannot
  85          * because of pending I/Os.  If set, UFSStoreState will
  86          * try to close again in the I/O callbacks.
  87          */
  88         bool try_closing;
  89     } flags;
  90     link_list *pending_reads;
  91     link_list *pending_writes;
  92     void queueRead(char *, size_t, off_t, STRCB *, void *);
  93     void queueWrite(char const *, size_t, off_t, FREE *);
  94     bool kickReadQueue();
  95     void drainWriteQueue();
  96     void tryClosing();
  97     char *read_buf;
  98
  99 private:
 100     void openDone();
 101     void freePending();
 102     void doWrite();
 103 };
 104
 105 } //namespace Ufs
 106 } //namespace Fs
 107
 108 #endif /* SQUID_FS_UFS_UFSSTORESTATE_H */
 109