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544 lines
18 KiB
C++
544 lines
18 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* vim:set ts=4 sw=4 sts=4 cin et: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef _nsDiskCacheMap_h_
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#define _nsDiskCacheMap_h_
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#include <limits.h>
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#include "prtypes.h"
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#include "prnetdb.h"
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#include "nsDebug.h"
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#include "nsError.h"
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#include "nsIFile.h"
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#include "nsDiskCache.h"
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#include "nsDiskCacheBlockFile.h"
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class nsDiskCacheBinding;
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struct nsDiskCacheEntry;
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/******************************************************************************
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* nsDiskCacheRecord
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*
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* Cache Location Format
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*
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* 1000 0000 0000 0000 0000 0000 0000 0000 : initialized bit
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*
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* 0011 0000 0000 0000 0000 0000 0000 0000 : File Selector (0 = separate file)
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* 0000 0011 0000 0000 0000 0000 0000 0000 : number of extra contiguous blocks 1-4
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* 0100 1100 0000 0000 0000 0000 0000 0000 : reserved bits
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* 0000 0000 1111 1111 1111 1111 1111 1111 : block# 0-16777216 (2^24)
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*
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* 0000 0000 1111 1111 1111 1111 0000 0000 : eFileSizeMask (size of file in k: see note)
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* 0000 0000 0000 0000 0000 0000 1111 1111 : eFileGenerationMask
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*
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* File Selector:
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* 0 = separate file on disk
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* 1 = 256 byte block file
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* 2 = 1k block file
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* 3 = 4k block file
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*
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* eFileSizeMask note: Files larger than 65535 KiB have this limit stored in
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* the location. The file itself must be examined to
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* determine its actual size if necessary.
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*
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*****************************************************************************/
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/*
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We have 3 block files with roughly the same max size (32MB)
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1 - block size 256B, number of blocks 131072
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2 - block size 1kB, number of blocks 32768
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3 - block size 4kB, number of blocks 8192
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*/
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#define kNumBlockFiles 3
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#define SIZE_SHIFT(idx) (2 * ((idx) - 1))
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#define BLOCK_SIZE_FOR_INDEX(idx) ((idx) ? (256 << SIZE_SHIFT(idx)) : 0)
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#define BITMAP_SIZE_FOR_INDEX(idx) ((idx) ? (131072 >> SIZE_SHIFT(idx)) : 0)
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// Min and max values for the number of records in the DiskCachemap
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#define kMinRecordCount 512
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#define kSeparateFile 0
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#define kBuckets (1 << 5) // must be a power of 2!
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// Maximum size in K which can be stored in the location (see eFileSizeMask).
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// Both data and metadata can be larger, but only up to kMaxDataSizeK can be
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// counted into total cache size. I.e. if there are entries where either data or
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// metadata is larger than kMaxDataSizeK, the total cache size will be
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// inaccurate (smaller) than the actual cache size. The alternative is to stat
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// the files to find the real size, which was decided against for performance
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// reasons. See bug #651100 comment #21.
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#define kMaxDataSizeK 0xFFFF
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// preallocate up to 1MB of separate cache file
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#define kPreallocateLimit 1 * 1024 * 1024
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class nsDiskCacheRecord {
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private:
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PRUint32 mHashNumber;
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PRUint32 mEvictionRank;
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PRUint32 mDataLocation;
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PRUint32 mMetaLocation;
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enum {
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eLocationInitializedMask = 0x80000000,
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eLocationSelectorMask = 0x30000000,
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eLocationSelectorOffset = 28,
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eExtraBlocksMask = 0x03000000,
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eExtraBlocksOffset = 24,
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eReservedMask = 0x4C000000,
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eBlockNumberMask = 0x00FFFFFF,
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eFileSizeMask = 0x00FFFF00,
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eFileSizeOffset = 8,
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eFileGenerationMask = 0x000000FF,
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eFileReservedMask = 0x4F000000
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};
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public:
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nsDiskCacheRecord()
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: mHashNumber(0), mEvictionRank(0), mDataLocation(0), mMetaLocation(0)
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{
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}
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bool ValidRecord()
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{
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if ((mDataLocation & eReservedMask) || (mMetaLocation & eReservedMask))
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return false;
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return true;
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}
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// HashNumber accessors
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PRUint32 HashNumber() const { return mHashNumber; }
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void SetHashNumber( PRUint32 hashNumber) { mHashNumber = hashNumber; }
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// EvictionRank accessors
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PRUint32 EvictionRank() const { return mEvictionRank; }
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void SetEvictionRank( PRUint32 rank) { mEvictionRank = rank ? rank : 1; }
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// DataLocation accessors
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bool DataLocationInitialized() const { return 0 != (mDataLocation & eLocationInitializedMask); }
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void ClearDataLocation() { mDataLocation = 0; }
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PRUint32 DataFile() const
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{
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return (PRUint32)(mDataLocation & eLocationSelectorMask) >> eLocationSelectorOffset;
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}
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void SetDataBlocks( PRUint32 index, PRUint32 startBlock, PRUint32 blockCount)
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{
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// clear everything
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mDataLocation = 0;
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// set file index
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NS_ASSERTION( index < (kNumBlockFiles + 1), "invalid location index");
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NS_ASSERTION( index > 0,"invalid location index");
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mDataLocation |= (index << eLocationSelectorOffset) & eLocationSelectorMask;
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// set startBlock
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NS_ASSERTION(startBlock == (startBlock & eBlockNumberMask), "invalid block number");
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mDataLocation |= startBlock & eBlockNumberMask;
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// set blockCount
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NS_ASSERTION( (blockCount>=1) && (blockCount<=4),"invalid block count");
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--blockCount;
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mDataLocation |= (blockCount << eExtraBlocksOffset) & eExtraBlocksMask;
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mDataLocation |= eLocationInitializedMask;
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}
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PRUint32 DataBlockCount() const
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{
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return (PRUint32)((mDataLocation & eExtraBlocksMask) >> eExtraBlocksOffset) + 1;
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}
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PRUint32 DataStartBlock() const
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{
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return (mDataLocation & eBlockNumberMask);
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}
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PRUint32 DataBlockSize() const
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{
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return BLOCK_SIZE_FOR_INDEX(DataFile());
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}
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PRUint32 DataFileSize() const { return (mDataLocation & eFileSizeMask) >> eFileSizeOffset; }
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void SetDataFileSize(PRUint32 size)
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{
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NS_ASSERTION((mDataLocation & eFileReservedMask) == 0, "bad location");
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mDataLocation &= ~eFileSizeMask; // clear eFileSizeMask
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mDataLocation |= (size << eFileSizeOffset) & eFileSizeMask;
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}
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PRUint8 DataFileGeneration() const
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{
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return (mDataLocation & eFileGenerationMask);
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}
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void SetDataFileGeneration( PRUint8 generation)
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{
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// clear everything, (separate file index = 0)
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mDataLocation = 0;
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mDataLocation |= generation & eFileGenerationMask;
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mDataLocation |= eLocationInitializedMask;
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}
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// MetaLocation accessors
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bool MetaLocationInitialized() const { return 0 != (mMetaLocation & eLocationInitializedMask); }
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void ClearMetaLocation() { mMetaLocation = 0; }
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PRUint32 MetaLocation() const { return mMetaLocation; }
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PRUint32 MetaFile() const
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{
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return (PRUint32)(mMetaLocation & eLocationSelectorMask) >> eLocationSelectorOffset;
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}
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void SetMetaBlocks( PRUint32 index, PRUint32 startBlock, PRUint32 blockCount)
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{
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// clear everything
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mMetaLocation = 0;
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// set file index
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NS_ASSERTION( index < (kNumBlockFiles + 1), "invalid location index");
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NS_ASSERTION( index > 0, "invalid location index");
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mMetaLocation |= (index << eLocationSelectorOffset) & eLocationSelectorMask;
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// set startBlock
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NS_ASSERTION(startBlock == (startBlock & eBlockNumberMask), "invalid block number");
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mMetaLocation |= startBlock & eBlockNumberMask;
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// set blockCount
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NS_ASSERTION( (blockCount>=1) && (blockCount<=4),"invalid block count");
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--blockCount;
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mMetaLocation |= (blockCount << eExtraBlocksOffset) & eExtraBlocksMask;
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mMetaLocation |= eLocationInitializedMask;
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}
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PRUint32 MetaBlockCount() const
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{
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return (PRUint32)((mMetaLocation & eExtraBlocksMask) >> eExtraBlocksOffset) + 1;
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}
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PRUint32 MetaStartBlock() const
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{
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return (mMetaLocation & eBlockNumberMask);
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}
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PRUint32 MetaBlockSize() const
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{
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return BLOCK_SIZE_FOR_INDEX(MetaFile());
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}
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PRUint32 MetaFileSize() const { return (mMetaLocation & eFileSizeMask) >> eFileSizeOffset; }
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void SetMetaFileSize(PRUint32 size)
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{
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mMetaLocation &= ~eFileSizeMask; // clear eFileSizeMask
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mMetaLocation |= (size << eFileSizeOffset) & eFileSizeMask;
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}
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PRUint8 MetaFileGeneration() const
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{
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return (mMetaLocation & eFileGenerationMask);
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}
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void SetMetaFileGeneration( PRUint8 generation)
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{
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// clear everything, (separate file index = 0)
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mMetaLocation = 0;
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mMetaLocation |= generation & eFileGenerationMask;
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mMetaLocation |= eLocationInitializedMask;
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}
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PRUint8 Generation() const
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{
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if ((mDataLocation & eLocationInitializedMask) &&
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(DataFile() == 0))
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return DataFileGeneration();
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if ((mMetaLocation & eLocationInitializedMask) &&
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(MetaFile() == 0))
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return MetaFileGeneration();
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return 0; // no generation
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}
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#if defined(IS_LITTLE_ENDIAN)
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void Swap()
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{
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mHashNumber = htonl(mHashNumber);
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mEvictionRank = htonl(mEvictionRank);
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mDataLocation = htonl(mDataLocation);
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mMetaLocation = htonl(mMetaLocation);
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}
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#endif
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#if defined(IS_LITTLE_ENDIAN)
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void Unswap()
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{
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mHashNumber = ntohl(mHashNumber);
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mEvictionRank = ntohl(mEvictionRank);
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mDataLocation = ntohl(mDataLocation);
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mMetaLocation = ntohl(mMetaLocation);
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}
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#endif
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};
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/******************************************************************************
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* nsDiskCacheRecordVisitor
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*****************************************************************************/
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enum { kDeleteRecordAndContinue = -1,
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kStopVisitingRecords = 0,
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kVisitNextRecord = 1
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};
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class nsDiskCacheRecordVisitor {
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public:
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virtual PRInt32 VisitRecord( nsDiskCacheRecord * mapRecord) = 0;
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};
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/******************************************************************************
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* nsDiskCacheHeader
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*****************************************************************************/
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struct nsDiskCacheHeader {
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PRUint32 mVersion; // cache version.
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PRUint32 mDataSize; // size of cache in units of 1024bytes.
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PRInt32 mEntryCount; // number of entries stored in cache.
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PRUint32 mIsDirty; // dirty flag.
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PRInt32 mRecordCount; // Number of records
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PRUint32 mEvictionRank[kBuckets]; // Highest EvictionRank of the bucket
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PRUint32 mBucketUsage[kBuckets]; // Number of used entries in the bucket
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nsDiskCacheHeader()
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: mVersion(nsDiskCache::kCurrentVersion)
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, mDataSize(0)
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, mEntryCount(0)
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, mIsDirty(true)
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, mRecordCount(0)
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{}
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void Swap()
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{
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#if defined(IS_LITTLE_ENDIAN)
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mVersion = htonl(mVersion);
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mDataSize = htonl(mDataSize);
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mEntryCount = htonl(mEntryCount);
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mIsDirty = htonl(mIsDirty);
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mRecordCount = htonl(mRecordCount);
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for (PRUint32 i = 0; i < kBuckets ; i++) {
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mEvictionRank[i] = htonl(mEvictionRank[i]);
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mBucketUsage[i] = htonl(mBucketUsage[i]);
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}
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#endif
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}
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void Unswap()
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{
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#if defined(IS_LITTLE_ENDIAN)
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mVersion = ntohl(mVersion);
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mDataSize = ntohl(mDataSize);
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mEntryCount = ntohl(mEntryCount);
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mIsDirty = ntohl(mIsDirty);
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mRecordCount = ntohl(mRecordCount);
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for (PRUint32 i = 0; i < kBuckets ; i++) {
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mEvictionRank[i] = ntohl(mEvictionRank[i]);
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mBucketUsage[i] = ntohl(mBucketUsage[i]);
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}
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#endif
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}
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};
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/******************************************************************************
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* nsDiskCacheMap
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*****************************************************************************/
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class nsDiskCacheMap {
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public:
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nsDiskCacheMap() :
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mCacheDirectory(nullptr),
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mMapFD(nullptr),
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mRecordArray(nullptr),
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mBufferSize(0),
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mBuffer(nullptr),
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mMaxRecordCount(16384) // this default value won't matter
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{ }
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~nsDiskCacheMap() {
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(void) Close(true);
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}
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/**
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* File Operations
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*
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* Open
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*
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* Creates a new cache map file if one doesn't exist.
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* Returns error if it detects change in format or cache wasn't closed.
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*/
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nsresult Open( nsIFile * cacheDirectory,
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nsDiskCache::CorruptCacheInfo * corruptInfo);
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nsresult Close(bool flush);
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nsresult Trim();
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nsresult FlushHeader();
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nsresult FlushRecords( bool unswap);
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void NotifyCapacityChange(PRUint32 capacity);
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/**
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* Record operations
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*/
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nsresult AddRecord( nsDiskCacheRecord * mapRecord, nsDiskCacheRecord * oldRecord);
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nsresult UpdateRecord( nsDiskCacheRecord * mapRecord);
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nsresult FindRecord( PRUint32 hashNumber, nsDiskCacheRecord * mapRecord);
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nsresult DeleteRecord( nsDiskCacheRecord * mapRecord);
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nsresult VisitRecords( nsDiskCacheRecordVisitor * visitor);
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nsresult EvictRecords( nsDiskCacheRecordVisitor * visitor);
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/**
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* Disk Entry operations
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*/
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nsresult DeleteStorage( nsDiskCacheRecord * record);
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nsresult GetFileForDiskCacheRecord( nsDiskCacheRecord * record,
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bool meta,
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bool createPath,
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nsIFile ** result);
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nsresult GetLocalFileForDiskCacheRecord( nsDiskCacheRecord * record,
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bool meta,
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bool createPath,
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nsIFile ** result);
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// On success, this returns the buffer owned by nsDiskCacheMap,
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// so it must not be deleted by the caller.
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nsDiskCacheEntry * ReadDiskCacheEntry( nsDiskCacheRecord * record);
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nsresult WriteDiskCacheEntry( nsDiskCacheBinding * binding);
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nsresult ReadDataCacheBlocks(nsDiskCacheBinding * binding, char * buffer, PRUint32 size);
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nsresult WriteDataCacheBlocks(nsDiskCacheBinding * binding, char * buffer, PRUint32 size);
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nsresult DeleteStorage( nsDiskCacheRecord * record, bool metaData);
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/**
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* Statistical Operations
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*/
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void IncrementTotalSize( PRUint32 delta)
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{
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mHeader.mDataSize += delta;
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mHeader.mIsDirty = true;
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}
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void DecrementTotalSize( PRUint32 delta)
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{
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NS_ASSERTION(mHeader.mDataSize >= delta, "disk cache size negative?");
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mHeader.mDataSize = mHeader.mDataSize > delta ? mHeader.mDataSize - delta : 0;
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mHeader.mIsDirty = true;
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}
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inline void IncrementTotalSize( PRUint32 blocks, PRUint32 blockSize)
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{
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// Round up to nearest K
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IncrementTotalSize(((blocks*blockSize) + 0x03FF) >> 10);
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}
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inline void DecrementTotalSize( PRUint32 blocks, PRUint32 blockSize)
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{
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// Round up to nearest K
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DecrementTotalSize(((blocks*blockSize) + 0x03FF) >> 10);
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}
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PRUint32 TotalSize() { return mHeader.mDataSize; }
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PRInt32 EntryCount() { return mHeader.mEntryCount; }
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private:
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/**
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* Private methods
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*/
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nsresult OpenBlockFiles(nsDiskCache::CorruptCacheInfo * corruptInfo);
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nsresult CloseBlockFiles(bool flush);
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bool CacheFilesExist();
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nsresult CreateCacheSubDirectories();
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PRUint32 CalculateFileIndex(PRUint32 size);
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nsresult GetBlockFileForIndex( PRUint32 index, nsIFile ** result);
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PRUint32 GetBlockSizeForIndex( PRUint32 index) const {
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return BLOCK_SIZE_FOR_INDEX(index);
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}
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PRUint32 GetBitMapSizeForIndex( PRUint32 index) const {
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return BITMAP_SIZE_FOR_INDEX(index);
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}
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// returns the bucket number
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PRUint32 GetBucketIndex( PRUint32 hashNumber) const {
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return (hashNumber & (kBuckets - 1));
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}
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// Gets the size of the bucket (in number of records)
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PRUint32 GetRecordsPerBucket() const {
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return mHeader.mRecordCount / kBuckets;
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}
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// Gets the first record in the bucket
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nsDiskCacheRecord *GetFirstRecordInBucket(PRUint32 bucket) const {
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return mRecordArray + bucket * GetRecordsPerBucket();
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}
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PRUint32 GetBucketRank(PRUint32 bucketIndex, PRUint32 targetRank);
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PRInt32 VisitEachRecord(PRUint32 bucketIndex,
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nsDiskCacheRecordVisitor * visitor,
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PRUint32 evictionRank);
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nsresult GrowRecords();
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nsresult ShrinkRecords();
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nsresult EnsureBuffer(PRUint32 bufSize);
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// The returned structure will point to the buffer owned by nsDiskCacheMap,
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// so it must not be deleted by the caller.
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nsDiskCacheEntry * CreateDiskCacheEntry(nsDiskCacheBinding * binding,
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PRUint32 * size);
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/**
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* data members
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*/
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private:
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nsCOMPtr<nsIFile> mCacheDirectory;
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PRFileDesc * mMapFD;
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nsDiskCacheRecord * mRecordArray;
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nsDiskCacheBlockFile mBlockFile[kNumBlockFiles];
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PRUint32 mBufferSize;
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char * mBuffer;
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nsDiskCacheHeader mHeader;
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PRInt32 mMaxRecordCount;
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};
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#endif // _nsDiskCacheMap_h_
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