netwerk/cache/nsDiskCacheBlockFile.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* vim: set sw=4 ts=8 et tw=80 : */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef _nsDiskCacheBlockFile_h_
   8 #define _nsDiskCacheBlockFile_h_
   9
  10 #include "mozilla/MemoryReporting.h"
  11 #include "nsIFile.h"
  12 #include "nsDiskCache.h"
  13
  14 /******************************************************************************
  15  *  nsDiskCacheBlockFile
  16  *
  17  *  The structure of a cache block file is a 4096 bytes bit map, followed by
  18  *  some number of blocks of mBlockSize.  The creator of a
  19  *  nsDiskCacheBlockFile object must provide the block size for a given file.
  20  *
  21  *****************************************************************************/
  22 class nsDiskCacheBlockFile {
  23 public:
  24     nsDiskCacheBlockFile()
  25            : mFD(nullptr)
  26            , mBitMap(nullptr)
  27            , mBlockSize(0)
  28            , mBitMapWords(0)
  29            , mFileSize(0)
  30            , mBitMapDirty(false)
  31             {}
  32     ~nsDiskCacheBlockFile() { (void) Close(true); }
  33
  34     nsresult  Open( nsIFile *  blockFile, uint32_t  blockSize,
  35                     uint32_t  bitMapSize, nsDiskCache::CorruptCacheInfo *  corruptInfo);
  36     nsresult  Close(bool flush);
  37
  38     /*
  39      * Trim
  40      * Truncates the block file to the end of the last allocated block.
  41      */
  42     nsresult  Trim() { return nsDiskCache::Truncate(mFD, CalcBlockFileSize()); }
  43     nsresult  DeallocateBlocks( int32_t  startBlock, int32_t  numBlocks);
  44     nsresult  WriteBlocks( void * buffer, uint32_t size, int32_t  numBlocks,
  45                            int32_t * startBlock);
  46     nsresult  ReadBlocks( void * buffer, int32_t  startBlock, int32_t  numBlocks,
  47                           int32_t * bytesRead);
  48
  49     size_t   SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);
  50
  51 private:
  52     nsresult  FlushBitMap();
  53     int32_t   AllocateBlocks( int32_t  numBlocks);
  54     nsresult  VerifyAllocation( int32_t startBlock, int32_t numBLocks);
  55     uint32_t  CalcBlockFileSize();
  56     bool   Write(int32_t offset, const void *buf, int32_t amount);
  57
  58 /**
  59  *  Data members
  60  */
  61     PRFileDesc *                mFD;
  62     uint32_t *                  mBitMap;      // XXX future: array of bit map blocks
  63     uint32_t                    mBlockSize;
  64     uint32_t                    mBitMapWords;
  65     int32_t                     mFileSize;
  66     bool                        mBitMapDirty;
  67 };
  68
  69 #endif // _nsDiskCacheBlockFile_h_