The Tor Browser: netwerk/cache/nsDiskCacheBlockFile.h@97036ab72558

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     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/. */

     7 #ifndef _nsDiskCacheBlockFile_h_

     8 #define _nsDiskCacheBlockFile_h_

    10 #include "mozilla/MemoryReporting.h"

    11 #include "nsIFile.h"

    12 #include "nsDiskCache.h"

    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); }

    34     nsresult  Open( nsIFile *  blockFile, uint32_t  blockSize,

    35                     uint32_t  bitMapSize, nsDiskCache::CorruptCacheInfo *  corruptInfo);

    36     nsresult  Close(bool flush);

    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);

    49     size_t   SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);

    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);

    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 };

    69 #endif // _nsDiskCacheBlockFile_h_

The Tor Browser / file revision

netwerk/cache/nsDiskCacheBlockFile.h@97036ab72558

netwerk/cache/nsDiskCacheBlockFile.h