LCOV - code coverage report
Current view: directory - netwerk/cache - nsDiskCacheMap.h (source / functions) Found Hit Coverage
Test: app.info Lines: 154 134 87.0 %
Date: 2012-06-02 Functions: 47 42 89.4 %

       1                 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2                 : /* vim:set ts=4 sw=4 sts=4 cin et: */
       3                 : /* ***** BEGIN LICENSE BLOCK *****
       4                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       5                 :  *
       6                 :  * The contents of this file are subject to the Mozilla Public License Version
       7                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       8                 :  * the License. You may obtain a copy of the License at
       9                 :  * http://www.mozilla.org/MPL/
      10                 :  *
      11                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      12                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      13                 :  * for the specific language governing rights and limitations under the
      14                 :  * License.
      15                 :  *
      16                 :  * The Original Code is nsDiskCacheMap.h, released
      17                 :  * March 23, 2001.
      18                 :  *
      19                 :  * The Initial Developer of the Original Code is
      20                 :  * Netscape Communications Corporation.
      21                 :  * Portions created by the Initial Developer are Copyright (C) 2001
      22                 :  * the Initial Developer. All Rights Reserved.
      23                 :  *
      24                 :  * Contributor(s):
      25                 :  *   Patrick C. Beard <beard@netscape.com>
      26                 :  *   Gordon Sheridan  <gordon@netscape.com>
      27                 :  *
      28                 :  * Alternatively, the contents of this file may be used under the terms of
      29                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      30                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      31                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      32                 :  * of those above. If you wish to allow use of your version of this file only
      33                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      34                 :  * use your version of this file under the terms of the MPL, indicate your
      35                 :  * decision by deleting the provisions above and replace them with the notice
      36                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      37                 :  * the provisions above, a recipient may use your version of this file under
      38                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      39                 :  *
      40                 :  * ***** END LICENSE BLOCK ***** */
      41                 : 
      42                 : #ifndef _nsDiskCacheMap_h_
      43                 : #define _nsDiskCacheMap_h_
      44                 : 
      45                 : #include <limits.h>
      46                 : 
      47                 : #include "prtypes.h"
      48                 : #include "prnetdb.h"
      49                 : #include "nsDebug.h"
      50                 : #include "nsError.h"
      51                 : #include "nsILocalFile.h"
      52                 : 
      53                 : #include "nsDiskCache.h"
      54                 : #include "nsDiskCacheBlockFile.h"
      55                 :  
      56                 :  
      57                 : class nsDiskCacheBinding;
      58                 : struct nsDiskCacheEntry;
      59                 : 
      60                 : /******************************************************************************
      61                 :  *  nsDiskCacheRecord
      62                 :  *
      63                 :  *   Cache Location Format
      64                 :  *
      65                 :  *    1000 0000 0000 0000 0000 0000 0000 0000 : initialized bit
      66                 :  *
      67                 :  *    0011 0000 0000 0000 0000 0000 0000 0000 : File Selector (0 = separate file)
      68                 :  *    0000 0011 0000 0000 0000 0000 0000 0000 : number of extra contiguous blocks 1-4
      69                 :  *    0100 1100 0000 0000 0000 0000 0000 0000 : reserved bits
      70                 :  *    0000 0000 1111 1111 1111 1111 1111 1111 : block#  0-16777216 (2^24)
      71                 :  *
      72                 :  *    0000 0000 1111 1111 1111 1111 0000 0000 : eFileSizeMask (size of file in k: see note)
      73                 :  *    0000 0000 0000 0000 0000 0000 1111 1111 : eFileGenerationMask
      74                 :  *
      75                 :  *  File Selector:
      76                 :  *      0 = separate file on disk
      77                 :  *      1 = 256 byte block file
      78                 :  *      2 = 1k block file
      79                 :  *      3 = 4k block file
      80                 :  *
      81                 :  *  eFileSizeMask note:  Files larger than 65535 KiB have this limit stored in
      82                 :  *                       the location.  The file itself must be examined to
      83                 :  *                       determine its actual size if necessary.
      84                 :  *
      85                 :  *****************************************************************************/
      86                 : 
      87                 : /*
      88                 :   We have 3 block files with roughly the same max size (32MB)
      89                 :     1 - block size 256B, number of blocks 131072
      90                 :     2 - block size  1kB, number of blocks  32768
      91                 :     3 - block size  4kB, number of blocks   8192
      92                 : */
      93                 : #define kNumBlockFiles             3
      94                 : #define SIZE_SHIFT(idx)            (2 * ((idx) - 1))
      95                 : #define BLOCK_SIZE_FOR_INDEX(idx)  ((idx) ? (256    << SIZE_SHIFT(idx)) : 0)
      96                 : #define BITMAP_SIZE_FOR_INDEX(idx) ((idx) ? (131072 >> SIZE_SHIFT(idx)) : 0)
      97                 : 
      98                 : // Min and max values for the number of records in the DiskCachemap
      99                 : #define kMinRecordCount    512
     100                 : 
     101                 : #define kSeparateFile      0
     102                 : #define kBuckets           (1 << 5)    // must be a power of 2!
     103                 : 
     104                 : // Maximum size in K which can be stored in the location (see eFileSizeMask).
     105                 : // Both data and metadata can be larger, but only up to kMaxDataSizeK can be
     106                 : // counted into total cache size. I.e. if there are entries where either data or
     107                 : // metadata is larger than kMaxDataSizeK, the total cache size will be
     108                 : // inaccurate (smaller) than the actual cache size. The alternative is to stat
     109                 : // the files to find the real size, which was decided against for performance
     110                 : // reasons. See bug #651100 comment #21.
     111                 : #define kMaxDataSizeK      0xFFFF
     112                 : 
     113                 : // preallocate up to 1MB of separate cache file
     114                 : #define kPreallocateLimit  1 * 1024 * 1024
     115                 : 
     116                 : class nsDiskCacheRecord {
     117                 : 
     118                 : private:
     119                 :     PRUint32    mHashNumber;
     120                 :     PRUint32    mEvictionRank;
     121                 :     PRUint32    mDataLocation;
     122                 :     PRUint32    mMetaLocation;
     123                 :  
     124                 :     enum {
     125                 :         eLocationInitializedMask = 0x80000000,
     126                 :         
     127                 :         eLocationSelectorMask    = 0x30000000,
     128                 :         eLocationSelectorOffset  = 28,
     129                 :         
     130                 :         eExtraBlocksMask         = 0x03000000,
     131                 :         eExtraBlocksOffset       = 24,
     132                 :         
     133                 :         eReservedMask            = 0x4C000000,
     134                 :         
     135                 :         eBlockNumberMask         = 0x00FFFFFF,
     136                 : 
     137                 :         eFileSizeMask            = 0x00FFFF00,
     138                 :         eFileSizeOffset          = 8,
     139                 :         eFileGenerationMask      = 0x000000FF,
     140                 :         eFileReservedMask        = 0x4F000000
     141                 :         
     142                 :     };
     143                 : 
     144                 : public:
     145            3360 :     nsDiskCacheRecord()
     146            3360 :         :   mHashNumber(0), mEvictionRank(0), mDataLocation(0), mMetaLocation(0)
     147                 :     {
     148            3360 :     }
     149                 :     
     150            2969 :     bool    ValidRecord()
     151                 :     {
     152            2969 :         if ((mDataLocation & eReservedMask) || (mMetaLocation & eReservedMask))
     153               0 :             return false;
     154            2969 :         return true;
     155                 :     }
     156                 :     
     157                 :     // HashNumber accessors
     158           99549 :     PRUint32  HashNumber() const                  { return mHashNumber; }
     159            1272 :     void      SetHashNumber( PRUint32 hashNumber) { mHashNumber = hashNumber; }
     160                 : 
     161                 :     // EvictionRank accessors
     162           13446 :     PRUint32  EvictionRank() const              { return mEvictionRank; }
     163            1211 :     void      SetEvictionRank( PRUint32 rank)   { mEvictionRank = rank ? rank : 1; }
     164                 : 
     165                 :     // DataLocation accessors
     166            1236 :     bool      DataLocationInitialized() const { return 0 != (mDataLocation & eLocationInitializedMask); }
     167             178 :     void      ClearDataLocation()       { mDataLocation = 0; }
     168                 :     
     169            1039 :     PRUint32  DataFile() const
     170                 :     {
     171            1039 :         return (PRUint32)(mDataLocation & eLocationSelectorMask) >> eLocationSelectorOffset;
     172                 :     }
     173                 : 
     174             476 :     void      SetDataBlocks( PRUint32 index, PRUint32 startBlock, PRUint32 blockCount)
     175                 :     {
     176                 :         // clear everything
     177             476 :         mDataLocation = 0;
     178                 :         
     179                 :         // set file index
     180             476 :         NS_ASSERTION( index < (kNumBlockFiles + 1), "invalid location index");
     181             476 :         NS_ASSERTION( index > 0,"invalid location index");
     182             476 :         mDataLocation |= (index << eLocationSelectorOffset) & eLocationSelectorMask;
     183                 : 
     184                 :         // set startBlock
     185             476 :         NS_ASSERTION(startBlock == (startBlock & eBlockNumberMask), "invalid block number");
     186             476 :         mDataLocation |= startBlock & eBlockNumberMask;
     187                 :         
     188                 :         // set blockCount
     189             476 :         NS_ASSERTION( (blockCount>=1) && (blockCount<=4),"invalid block count");
     190             476 :         --blockCount;
     191             476 :         mDataLocation |= (blockCount << eExtraBlocksOffset) & eExtraBlocksMask;
     192                 :         
     193             476 :         mDataLocation |= eLocationInitializedMask;
     194             476 :     }
     195                 : 
     196             304 :     PRUint32   DataBlockCount() const
     197                 :     {
     198             304 :         return (PRUint32)((mDataLocation & eExtraBlocksMask) >> eExtraBlocksOffset) + 1;
     199                 :     }
     200                 : 
     201             304 :     PRUint32   DataStartBlock() const
     202                 :     {
     203             304 :         return (mDataLocation & eBlockNumberMask);
     204                 :     }
     205                 :     
     206                 :     PRUint32   DataBlockSize() const
     207                 :     {
     208                 :         return BLOCK_SIZE_FOR_INDEX(DataFile());
     209                 :     }
     210                 :     
     211             232 :     PRUint32   DataFileSize() const  { return (mDataLocation & eFileSizeMask) >> eFileSizeOffset; }
     212             155 :     void       SetDataFileSize(PRUint32  size)
     213                 :     {
     214             155 :         NS_ASSERTION((mDataLocation & eFileReservedMask) == 0, "bad location");
     215             155 :         mDataLocation &= ~eFileSizeMask;    // clear eFileSizeMask
     216             155 :         mDataLocation |= (size << eFileSizeOffset) & eFileSizeMask;
     217             155 :     }
     218                 : 
     219              75 :     PRUint8   DataFileGeneration() const
     220                 :     {
     221              75 :         return (mDataLocation & eFileGenerationMask);
     222                 :     }
     223                 : 
     224              37 :     void       SetDataFileGeneration( PRUint8 generation)
     225                 :     {
     226                 :         // clear everything, (separate file index = 0)
     227              37 :         mDataLocation = 0;
     228              37 :         mDataLocation |= generation & eFileGenerationMask;
     229              37 :         mDataLocation |= eLocationInitializedMask;
     230              37 :     }
     231                 : 
     232                 :     // MetaLocation accessors
     233             939 :     bool      MetaLocationInitialized() const { return 0 != (mMetaLocation & eLocationInitializedMask); }
     234             333 :     void      ClearMetaLocation()             { mMetaLocation = 0; }   
     235             660 :     PRUint32  MetaLocation() const            { return mMetaLocation; }
     236                 :     
     237            1051 :     PRUint32  MetaFile() const
     238                 :     {
     239            1051 :         return (PRUint32)(mMetaLocation & eLocationSelectorMask) >> eLocationSelectorOffset;
     240                 :     }
     241                 : 
     242             660 :     void      SetMetaBlocks( PRUint32 index, PRUint32 startBlock, PRUint32 blockCount)
     243                 :     {
     244                 :         // clear everything
     245             660 :         mMetaLocation = 0;
     246                 :         
     247                 :         // set file index
     248             660 :         NS_ASSERTION( index < (kNumBlockFiles + 1), "invalid location index");
     249             660 :         NS_ASSERTION( index > 0, "invalid location index");
     250             660 :         mMetaLocation |= (index << eLocationSelectorOffset) & eLocationSelectorMask;
     251                 : 
     252                 :         // set startBlock
     253             660 :         NS_ASSERTION(startBlock == (startBlock & eBlockNumberMask), "invalid block number");
     254             660 :         mMetaLocation |= startBlock & eBlockNumberMask;
     255                 :         
     256                 :         // set blockCount
     257             660 :         NS_ASSERTION( (blockCount>=1) && (blockCount<=4),"invalid block count");
     258             660 :         --blockCount;
     259             660 :         mMetaLocation |= (blockCount << eExtraBlocksOffset) & eExtraBlocksMask;
     260                 :         
     261             660 :         mMetaLocation |= eLocationInitializedMask;
     262             660 :     }
     263                 : 
     264             558 :     PRUint32   MetaBlockCount() const
     265                 :     {
     266             558 :         return (PRUint32)((mMetaLocation & eExtraBlocksMask) >> eExtraBlocksOffset) + 1;
     267                 :     }
     268                 : 
     269             558 :     PRUint32   MetaStartBlock() const
     270                 :     {
     271             558 :         return (mMetaLocation & eBlockNumberMask);
     272                 :     }
     273                 : 
     274                 :     PRUint32   MetaBlockSize() const
     275                 :     {
     276                 :         return BLOCK_SIZE_FOR_INDEX(MetaFile());
     277                 :     }
     278                 :     
     279              54 :     PRUint32   MetaFileSize() const  { return (mMetaLocation & eFileSizeMask) >> eFileSizeOffset; }
     280               0 :     void       SetMetaFileSize(PRUint32  size)
     281                 :     {
     282               0 :         mMetaLocation &= ~eFileSizeMask;    // clear eFileSizeMask
     283               0 :         mMetaLocation |= (size << eFileSizeOffset) & eFileSizeMask;
     284               0 :     }
     285                 : 
     286               0 :     PRUint8   MetaFileGeneration() const
     287                 :     {
     288               0 :         return (mMetaLocation & eFileGenerationMask);
     289                 :     }
     290                 : 
     291               0 :     void       SetMetaFileGeneration( PRUint8 generation)
     292                 :     {
     293                 :         // clear everything, (separate file index = 0)
     294               0 :         mMetaLocation = 0;
     295               0 :         mMetaLocation |= generation & eFileGenerationMask;
     296               0 :         mMetaLocation |= eLocationInitializedMask;
     297               0 :     }
     298                 : 
     299             960 :     PRUint8   Generation() const
     300                 :     {
     301            1311 :         if ((mDataLocation & eLocationInitializedMask)  &&
     302             351 :             (DataFile() == 0))
     303              75 :             return DataFileGeneration();
     304                 :             
     305            1161 :         if ((mMetaLocation & eLocationInitializedMask)  &&
     306             276 :             (MetaFile() == 0))
     307               0 :             return MetaFileGeneration();
     308                 :         
     309             885 :         return 0;  // no generation
     310                 :     }
     311                 : 
     312                 : #if defined(IS_LITTLE_ENDIAN)
     313             376 :     void        Swap()
     314                 :     {
     315             376 :         mHashNumber   = htonl(mHashNumber);
     316             376 :         mEvictionRank = htonl(mEvictionRank);
     317             376 :         mDataLocation = htonl(mDataLocation);
     318             376 :         mMetaLocation = htonl(mMetaLocation);
     319             376 :     }
     320                 : #endif
     321                 :     
     322                 : #if defined(IS_LITTLE_ENDIAN)
     323               0 :     void        Unswap()
     324                 :     {
     325               0 :         mHashNumber   = ntohl(mHashNumber);
     326               0 :         mEvictionRank = ntohl(mEvictionRank);
     327               0 :         mDataLocation = ntohl(mDataLocation);
     328               0 :         mMetaLocation = ntohl(mMetaLocation);
     329               0 :     }
     330                 : #endif
     331                 : 
     332                 : };
     333                 : 
     334                 : 
     335                 : /******************************************************************************
     336                 :  *  nsDiskCacheRecordVisitor
     337                 :  *****************************************************************************/
     338                 : 
     339                 : enum {  kDeleteRecordAndContinue = -1,
     340                 :         kStopVisitingRecords     =  0,
     341                 :         kVisitNextRecord         =  1
     342                 : };
     343                 : 
     344              17 : class nsDiskCacheRecordVisitor {
     345                 :     public:
     346                 : 
     347                 :     virtual PRInt32  VisitRecord( nsDiskCacheRecord *  mapRecord) = 0;
     348                 : };
     349                 : 
     350                 : 
     351                 : /******************************************************************************
     352                 :  *  nsDiskCacheHeader
     353                 :  *****************************************************************************/
     354                 : 
     355                 : struct nsDiskCacheHeader {
     356                 :     PRUint32    mVersion;                           // cache version.
     357                 :     PRUint32    mDataSize;                          // size of cache in units of 1024bytes.
     358                 :     PRInt32     mEntryCount;                        // number of entries stored in cache.
     359                 :     PRUint32    mIsDirty;                           // dirty flag.
     360                 :     PRInt32     mRecordCount;                       // Number of records
     361                 :     PRUint32    mEvictionRank[kBuckets];            // Highest EvictionRank of the bucket
     362                 :     PRUint32    mBucketUsage[kBuckets];             // Number of used entries in the bucket
     363                 :   
     364             175 :     nsDiskCacheHeader()
     365                 :         : mVersion(nsDiskCache::kCurrentVersion)
     366                 :         , mDataSize(0)
     367                 :         , mEntryCount(0)
     368                 :         , mIsDirty(true)
     369             175 :         , mRecordCount(0)
     370             175 :     {}
     371                 : 
     372             411 :     void        Swap()
     373                 :     {
     374                 : #if defined(IS_LITTLE_ENDIAN)
     375             411 :         mVersion     = htonl(mVersion);
     376             411 :         mDataSize    = htonl(mDataSize);
     377             411 :         mEntryCount  = htonl(mEntryCount);
     378             411 :         mIsDirty     = htonl(mIsDirty);
     379             411 :         mRecordCount = htonl(mRecordCount);
     380                 : 
     381           13563 :         for (PRUint32 i = 0; i < kBuckets ; i++) {
     382           13152 :             mEvictionRank[i] = htonl(mEvictionRank[i]);
     383           13152 :             mBucketUsage[i]  = htonl(mBucketUsage[i]);
     384                 :         }
     385                 : #endif
     386             411 :     }
     387                 :     
     388             411 :     void        Unswap()
     389                 :     {
     390                 : #if defined(IS_LITTLE_ENDIAN)
     391             411 :         mVersion     = ntohl(mVersion);
     392             411 :         mDataSize    = ntohl(mDataSize);
     393             411 :         mEntryCount  = ntohl(mEntryCount);
     394             411 :         mIsDirty     = ntohl(mIsDirty);
     395             411 :         mRecordCount = ntohl(mRecordCount);
     396                 : 
     397           13563 :         for (PRUint32 i = 0; i < kBuckets ; i++) {
     398           13152 :             mEvictionRank[i] = ntohl(mEvictionRank[i]);
     399           13152 :             mBucketUsage[i]  = ntohl(mBucketUsage[i]);
     400                 :         }
     401                 : #endif
     402             411 :     }
     403                 : };
     404                 : 
     405                 : 
     406                 : /******************************************************************************
     407                 :  *  nsDiskCacheMap
     408                 :  *****************************************************************************/
     409                 : 
     410                 : class nsDiskCacheMap {
     411                 : public:
     412                 : 
     413             175 :      nsDiskCacheMap() : 
     414                 :         mCacheDirectory(nsnull),
     415                 :         mMapFD(nsnull),
     416                 :         mRecordArray(nsnull),
     417                 :         mBufferSize(0),
     418                 :         mBuffer(nsnull),
     419             175 :         mMaxRecordCount(16384) // this default value won't matter
     420             175 :     { }
     421                 : 
     422            1225 :     ~nsDiskCacheMap() {
     423             175 :         (void) Close(true);
     424            1050 :     }
     425                 : 
     426                 : /**
     427                 :  *  File Operations
     428                 :  *
     429                 :  *  Open
     430                 :  *
     431                 :  *  Creates a new cache map file if one doesn't exist.
     432                 :  *  Returns error if it detects change in format or cache wasn't closed.
     433                 :  */
     434                 :     nsresult  Open( nsILocalFile *  cacheDirectory);
     435                 :     nsresult  Close(bool flush);
     436                 :     nsresult  Trim();
     437                 : 
     438                 :     nsresult  FlushHeader();
     439                 :     nsresult  FlushRecords( bool unswap);
     440                 : 
     441                 :     void      NotifyCapacityChange(PRUint32 capacity);
     442                 : 
     443                 : /**
     444                 :  *  Record operations
     445                 :  */
     446                 :     nsresult AddRecord( nsDiskCacheRecord *  mapRecord, nsDiskCacheRecord * oldRecord);
     447                 :     nsresult UpdateRecord( nsDiskCacheRecord *  mapRecord);
     448                 :     nsresult FindRecord( PRUint32  hashNumber, nsDiskCacheRecord *  mapRecord);
     449                 :     nsresult DeleteRecord( nsDiskCacheRecord *  mapRecord);
     450                 :     nsresult VisitRecords( nsDiskCacheRecordVisitor * visitor);
     451                 :     nsresult EvictRecords( nsDiskCacheRecordVisitor * visitor);
     452                 : 
     453                 : /**
     454                 :  *  Disk Entry operations
     455                 :  */
     456                 :     nsresult    DeleteStorage( nsDiskCacheRecord *  record);
     457                 : 
     458                 :     nsresult    GetFileForDiskCacheRecord( nsDiskCacheRecord * record,
     459                 :                                            bool                meta,
     460                 :                                            bool                createPath,
     461                 :                                            nsIFile **          result);
     462                 :                                           
     463                 :     nsresult    GetLocalFileForDiskCacheRecord( nsDiskCacheRecord *  record,
     464                 :                                                 bool                 meta,
     465                 :                                                 bool                 createPath,
     466                 :                                                 nsILocalFile **      result);
     467                 : 
     468                 :     // On success, this returns the buffer owned by nsDiskCacheMap,
     469                 :     // so it must not be deleted by the caller.
     470                 :     nsDiskCacheEntry * ReadDiskCacheEntry( nsDiskCacheRecord *  record);
     471                 : 
     472                 :     nsresult    WriteDiskCacheEntry( nsDiskCacheBinding *  binding);
     473                 :     
     474                 :     nsresult    ReadDataCacheBlocks(nsDiskCacheBinding * binding, char * buffer, PRUint32 size);
     475                 :     nsresult    WriteDataCacheBlocks(nsDiskCacheBinding * binding, char * buffer, PRUint32 size);
     476                 :     nsresult    DeleteStorage( nsDiskCacheRecord * record, bool metaData);
     477                 :     
     478                 :     /**
     479                 :      *  Statistical Operations
     480                 :      */
     481            1291 :     void     IncrementTotalSize( PRUint32  delta)
     482                 :              {
     483            1291 :                 mHeader.mDataSize += delta;
     484            1291 :                 mHeader.mIsDirty   = true;
     485            1291 :              }
     486                 :              
     487             666 :     void     DecrementTotalSize( PRUint32  delta)
     488                 :              {
     489             666 :                 NS_ASSERTION(mHeader.mDataSize >= delta, "disk cache size negative?");
     490             666 :                 mHeader.mDataSize  = mHeader.mDataSize > delta ? mHeader.mDataSize - delta : 0;               
     491             666 :                 mHeader.mIsDirty   = true;
     492             666 :              }
     493                 :     
     494            1136 :     inline void IncrementTotalSize( PRUint32  blocks, PRUint32 blockSize)
     495                 :              {
     496                 :                 // Round up to nearest K
     497            1136 :                 IncrementTotalSize(((blocks*blockSize) + 0x03FF) >> 10);
     498            1136 :              }
     499                 : 
     500             423 :     inline void DecrementTotalSize( PRUint32  blocks, PRUint32 blockSize)
     501                 :              {
     502                 :                 // Round up to nearest K
     503             423 :                 DecrementTotalSize(((blocks*blockSize) + 0x03FF) >> 10);
     504             423 :              }
     505                 :                  
     506            1547 :     PRUint32 TotalSize()   { return mHeader.mDataSize; }
     507                 :     
     508               0 :     PRInt32  EntryCount()  { return mHeader.mEntryCount; }
     509                 : 
     510                 : 
     511                 : private:
     512                 : 
     513                 :     /**
     514                 :      *  Private methods
     515                 :      */
     516                 :     nsresult    OpenBlockFiles();
     517                 :     nsresult    CloseBlockFiles(bool flush);
     518                 :     bool        CacheFilesExist();
     519                 : 
     520                 :     nsresult    CreateCacheSubDirectories();
     521                 : 
     522                 :     PRUint32    CalculateFileIndex(PRUint32 size);
     523                 : 
     524                 :     nsresult    GetBlockFileForIndex( PRUint32 index, nsILocalFile ** result);
     525            2546 :     PRUint32    GetBlockSizeForIndex( PRUint32 index) const {
     526            2546 :         return BLOCK_SIZE_FOR_INDEX(index);
     527                 :     }
     528             708 :     PRUint32    GetBitMapSizeForIndex( PRUint32 index) const {
     529             708 :         return BITMAP_SIZE_FOR_INDEX(index);
     530                 :     }
     531                 :     
     532                 :     // returns the bucket number    
     533            4654 :     PRUint32 GetBucketIndex( PRUint32 hashNumber) const {
     534            4654 :         return (hashNumber & (kBuckets - 1));
     535                 :     }
     536                 :     
     537                 :     // Gets the size of the bucket (in number of records)
     538            9877 :     PRUint32 GetRecordsPerBucket() const {
     539            9877 :         return mHeader.mRecordCount / kBuckets;
     540                 :     }
     541                 : 
     542                 :     // Gets the first record in the bucket
     543            8775 :     nsDiskCacheRecord *GetFirstRecordInBucket(PRUint32 bucket) const {
     544            8775 :         return mRecordArray + bucket * GetRecordsPerBucket();
     545                 :     }
     546                 : 
     547                 :     PRUint32 GetBucketRank(PRUint32 bucketIndex, PRUint32 targetRank);
     548                 : 
     549                 :     PRInt32  VisitEachRecord(PRUint32                    bucketIndex,
     550                 :                              nsDiskCacheRecordVisitor *  visitor,
     551                 :                              PRUint32                    evictionRank);
     552                 : 
     553                 :     nsresult GrowRecords();
     554                 :     nsresult ShrinkRecords();
     555                 : 
     556                 :     nsresult EnsureBuffer(PRUint32 bufSize);
     557                 : 
     558                 :     // The returned structure will point to the buffer owned by nsDiskCacheMap, 
     559                 :     // so it must not be deleted by the caller.
     560                 :     nsDiskCacheEntry *  CreateDiskCacheEntry(nsDiskCacheBinding *  binding,
     561                 :                                              PRUint32 * size);
     562                 : 
     563                 : /**
     564                 :  *  data members
     565                 :  */
     566                 : private:
     567                 :     nsCOMPtr<nsILocalFile>  mCacheDirectory;
     568                 :     PRFileDesc *            mMapFD;
     569                 :     nsDiskCacheRecord *     mRecordArray;
     570                 :     nsDiskCacheBlockFile    mBlockFile[kNumBlockFiles];
     571                 :     PRUint32                mBufferSize;
     572                 :     char *                  mBuffer;
     573                 :     nsDiskCacheHeader       mHeader;
     574                 :     PRInt32                 mMaxRecordCount;
     575                 : };
     576                 : 
     577                 : #endif // _nsDiskCacheMap_h_

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