src/fs/ufs/UFSStoreState.h

   1 /*
   2  * Copyright (C) 1996-2016 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() :
  52             buf(nullptr),
  53             size(0),
  54             offset(0),
  55             callback(nullptr),
  56             callback_data(nullptr)
  57         {}
  58
  59         char *buf;
  60         size_t size;
  61         off_t offset;
  62         STRCB *callback;
  63         void *callback_data;
  64     };
  65
  66     class _queued_write
  67     {
  68         MEMPROXY_CLASS(UFSStoreState::_queued_write);
  69     public:
  70         _queued_write() :
  71             buf(nullptr),
  72             size(0),
  73             offset(0),
  74             free_func(nullptr)
  75         {}
  76
  77         char const *buf;
  78         size_t size;
  79         off_t offset;
  80         FREE *free_func;
  81     };
  82
  83     /** \todo These should be in the IO strategy */
  84
  85     struct {
  86         /**
  87          * DPW 2006-05-24
  88          * the write_draining flag is used to avoid recursion inside
  89          * the UFSStoreState::drainWriteQueue() method.
  90          */
  91         bool write_draining;
  92         /**
  93          * DPW 2006-05-24
  94          * The try_closing flag is set by UFSStoreState::tryClosing()
  95          * when UFSStoreState wants to close the file, but cannot
  96          * because of pending I/Os.  If set, UFSStoreState will
  97          * try to close again in the I/O callbacks.
  98          */
  99         bool try_closing;
 100     } flags;
 101     link_list *pending_reads;
 102     link_list *pending_writes;
 103     void queueRead(char *, size_t, off_t, STRCB *, void *);
 104     void queueWrite(char const *, size_t, off_t, FREE *);
 105     bool kickReadQueue();
 106     void drainWriteQueue();
 107     void tryClosing();
 108     char *read_buf;
 109
 110 private:
 111     void openDone();
 112     void freePending();
 113     void doWrite();
 114 };
 115
 116 } //namespace Ufs
 117 } //namespace Fs
 118
 119 #endif /* SQUID_FS_UFS_UFSSTORESTATE_H */
 120