src/StoreIOState.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_STOREIOSTATE_H
  10 #define SQUID_STOREIOSTATE_H
  11
  12 #include "base/RefCount.h"
  13 #include "cbdata.h"
  14
  15 class StoreIOState : public RefCountable
  16 {
  17
  18 public:
  19     typedef RefCount<StoreIOState> Pointer;
  20
  21     /*
  22      * STRCB is the "store read callback".  STRCB functions are
  23      * passed to storeRead().  Examples of STRCB callbacks are:
  24      * storeClientReadBody
  25      * storeClientReadHeader
  26      */
  27     typedef void STRCB(void *their_data, const char *buf, ssize_t len, StoreIOState::Pointer self);
  28
  29     /*
  30      * STFNCB is the "store file number callback."  It is called
  31      * when an underlying storage module has allocated the swap
  32      * file number and also indicates that the swap file has been
  33      * opened for reading or writing.  STFNCB functions are passed
  34      * to storeCreate() and storeOpen().  Examples of STFNCB callbacks
  35      * are:
  36      * storeSwapInFileNotify
  37      * storeSwapOutFileNotify
  38      */
  39     typedef void STFNCB(void *their_data, int errflag, StoreIOState::Pointer self);
  40
  41     /*
  42      * STIOCB is the "store close callback" for store files.  It
  43      * is called when the store file is closed.  STIOCB functions
  44      * are passed to storeCreate() and storeOpen(). Examples of
  45      * STIOCB callbacks are:
  46      * storeSwapOutFileClosed
  47      * storeSwapInFileClosed
  48      */
  49     typedef void STIOCB(void *their_data, int errflag, StoreIOState::Pointer self);
  50
  51     /* StoreIOState does not get mempooled - it's children do */
  52     void *operator new (size_t amount);
  53     void operator delete (void *address);
  54     virtual ~StoreIOState();
  55
  56     StoreIOState();
  57
  58     off_t offset() const;
  59
  60     virtual void read_(char *buf, size_t size, off_t offset, STRCB * callback, void *callback_data) = 0;
  61     /** write the given buffer and free it when it is no longer needed
  62      *  \param offset zero for the very first write and -1 for all other writes
  63      *  \retval false if write failed (callback has been or will be called)
  64      */
  65     virtual bool write(char const *buf, size_t size, off_t offset, FREE * free_func) = 0;
  66
  67     typedef enum {
  68         wroteAll, ///< success: caller supplied all data it wanted to swap out
  69         writerGone, ///< failure: caller left before swapping out everything
  70         readerDone ///< success or failure: either way, stop swapping in
  71     } CloseHow;
  72     virtual void close(int how) = 0; ///< finish or abort swapping per CloseHow
  73
  74     sdirno swap_dirn;
  75     sfileno swap_filen;
  76     StoreEntry *e;      /* Need this so the FS layers can play god */
  77     mode_t mode;
  78     off_t offset_; ///< number of bytes written or read for this entry so far
  79     STFNCB *file_callback;  /* called on delayed sfileno assignments */
  80     STIOCB *callback;
  81     void *callback_data;
  82
  83     struct {
  84         STRCB *callback;
  85         void *callback_data;
  86     } read;
  87
  88     struct {
  89         bool closing;   /* debugging aid */
  90     } flags;
  91 };
  92
  93 StoreIOState::Pointer storeCreate(StoreEntry *, StoreIOState::STFNCB *, StoreIOState::STIOCB *, void *);
  94 StoreIOState::Pointer storeOpen(StoreEntry *, StoreIOState::STFNCB *, StoreIOState::STIOCB *, void *);
  95 void storeClose(StoreIOState::Pointer, int how);
  96 void storeRead(StoreIOState::Pointer, char *, size_t, off_t, StoreIOState::STRCB *, void *);
  97 void storeIOWrite(StoreIOState::Pointer, char const *, size_t, off_t, FREE *);
  98
  99 #endif /* SQUID_STOREIOSTATE_H */
 100