gecko/netwerk/cache/nsDiskCacheMap.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:set ts=4 sw=4 sts=4 cin et: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is nsDiskCacheMap.h, released
* March 23, 2001.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Patrick C. Beard <beard@netscape.com>
* Gordon Sheridan <gordon@netscape.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef _nsDiskCacheMap_h_
#define _nsDiskCacheMap_h_
#include <limits.h>
#include "prtypes.h"
#include "prnetdb.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsILocalFile.h"
#include "nsDiskCache.h"
#include "nsDiskCacheBlockFile.h"
class nsDiskCacheBinding;
struct nsDiskCacheEntry;
/******************************************************************************
* nsDiskCacheRecord
*
* Cache Location Format
*
* 1000 0000 0000 0000 0000 0000 0000 0000 : initialized bit
*
* 0011 0000 0000 0000 0000 0000 0000 0000 : File Selector (0 = separate file)
* 0000 0011 0000 0000 0000 0000 0000 0000 : number of extra contiguous blocks 1-4
* 0100 1100 0000 0000 0000 0000 0000 0000 : reserved bits
* 0000 0000 1111 1111 1111 1111 1111 1111 : block# 0-16777216 (2^24)
*
* 0000 0000 1111 1111 1111 1111 0000 0000 : eFileSizeMask (size of file in k: see note)
* 0000 0000 0000 0000 0000 0000 1111 1111 : eFileGenerationMask
*
* File Selector:
* 0 = separate file on disk
* 1 = 256 byte block file
* 2 = 1k block file
* 3 = 4k block file
*
* eFileSizeMask note: Files larger than 64 MiB have zero size stored in the
* location. The file itself must be examined to determine
* its actual size. (XXX This is broken in places -darin)
*
*****************************************************************************/
#define BLOCK_SIZE_FOR_INDEX(index) ((index) ? (256 << (2 * ((index) - 1))) : 0)
// Min and max values for the number of records in the DiskCachemap
#define kMinRecordCount 512
#define kSeparateFile 0
#define kMaxDataFileSize 0x3FFFC00 // 65535 KiB (see bug #443067)
#define kBuckets (1 << 5) // must be a power of 2!
class nsDiskCacheRecord {
private:
PRUint32 mHashNumber;
PRUint32 mEvictionRank;
PRUint32 mDataLocation;
PRUint32 mMetaLocation;
enum {
eLocationInitializedMask = 0x80000000,
eLocationSelectorMask = 0x30000000,
eLocationSelectorOffset = 28,
eExtraBlocksMask = 0x03000000,
eExtraBlocksOffset = 24,
eReservedMask = 0x4C000000,
eBlockNumberMask = 0x00FFFFFF,
eFileSizeMask = 0x00FFFF00,
eFileSizeOffset = 8,
eFileGenerationMask = 0x000000FF,
eFileReservedMask = 0x4F000000
};
public:
nsDiskCacheRecord()
: mHashNumber(0), mEvictionRank(0), mDataLocation(0), mMetaLocation(0)
{
}
PRBool ValidRecord()
{
if ((mDataLocation & eReservedMask) || (mMetaLocation & eReservedMask))
return PR_FALSE;
return PR_TRUE;
}
// HashNumber accessors
PRUint32 HashNumber() const { return mHashNumber; }
void SetHashNumber( PRUint32 hashNumber) { mHashNumber = hashNumber; }
// EvictionRank accessors
PRUint32 EvictionRank() const { return mEvictionRank; }
void SetEvictionRank( PRUint32 rank) { mEvictionRank = rank ? rank : 1; }
// DataLocation accessors
PRBool DataLocationInitialized() const { return 0 != (mDataLocation & eLocationInitializedMask); }
void ClearDataLocation() { mDataLocation = 0; }
PRUint32 DataFile() const
{
return (PRUint32)(mDataLocation & eLocationSelectorMask) >> eLocationSelectorOffset;
}
void SetDataBlocks( PRUint32 index, PRUint32 startBlock, PRUint32 blockCount)
{
// clear everything
mDataLocation = 0;
// set file index
NS_ASSERTION( index < 4,"invalid location index");
NS_ASSERTION( index > 0,"invalid location index");
mDataLocation |= (index << eLocationSelectorOffset) & eLocationSelectorMask;
// set startBlock
NS_ASSERTION(startBlock == (startBlock & eBlockNumberMask), "invalid block number");
mDataLocation |= startBlock & eBlockNumberMask;
// set blockCount
NS_ASSERTION( (blockCount>=1) && (blockCount<=4),"invalid block count");
--blockCount;
mDataLocation |= (blockCount << eExtraBlocksOffset) & eExtraBlocksMask;
mDataLocation |= eLocationInitializedMask;
}
PRUint32 DataBlockCount() const
{
return (PRUint32)((mDataLocation & eExtraBlocksMask) >> eExtraBlocksOffset) + 1;
}
PRUint32 DataStartBlock() const
{
return (mDataLocation & eBlockNumberMask);
}
PRUint32 DataBlockSize() const
{
return BLOCK_SIZE_FOR_INDEX(DataFile());
}
PRUint32 DataFileSize() const { return (mDataLocation & eFileSizeMask) >> eFileSizeOffset; }
void SetDataFileSize(PRUint32 size)
{
NS_ASSERTION((mDataLocation & eFileReservedMask) == 0, "bad location");
mDataLocation &= ~eFileSizeMask; // clear eFileSizeMask
mDataLocation |= (size << eFileSizeOffset) & eFileSizeMask;
}
PRUint8 DataFileGeneration() const
{
return (mDataLocation & eFileGenerationMask);
}
void SetDataFileGeneration( PRUint8 generation)
{
// clear everything, (separate file index = 0)
mDataLocation = 0;
mDataLocation |= generation & eFileGenerationMask;
mDataLocation |= eLocationInitializedMask;
}
// MetaLocation accessors
PRBool MetaLocationInitialized() const { return 0 != (mMetaLocation & eLocationInitializedMask); }
void ClearMetaLocation() { mMetaLocation = 0; }
PRUint32 MetaLocation() const { return mMetaLocation; }
PRUint32 MetaFile() const
{
return (PRUint32)(mMetaLocation & eLocationSelectorMask) >> eLocationSelectorOffset;
}
void SetMetaBlocks( PRUint32 index, PRUint32 startBlock, PRUint32 blockCount)
{
// clear everything
mMetaLocation = 0;
// set file index
NS_ASSERTION( index < 4, "invalid location index");
NS_ASSERTION( index > 0, "invalid location index");
mMetaLocation |= (index << eLocationSelectorOffset) & eLocationSelectorMask;
// set startBlock
NS_ASSERTION(startBlock == (startBlock & eBlockNumberMask), "invalid block number");
mMetaLocation |= startBlock & eBlockNumberMask;
// set blockCount
NS_ASSERTION( (blockCount>=1) && (blockCount<=4),"invalid block count");
--blockCount;
mMetaLocation |= (blockCount << eExtraBlocksOffset) & eExtraBlocksMask;
mMetaLocation |= eLocationInitializedMask;
}
PRUint32 MetaBlockCount() const
{
return (PRUint32)((mMetaLocation & eExtraBlocksMask) >> eExtraBlocksOffset) + 1;
}
PRUint32 MetaStartBlock() const
{
return (mMetaLocation & eBlockNumberMask);
}
PRUint32 MetaBlockSize() const
{
return BLOCK_SIZE_FOR_INDEX(MetaFile());
}
PRUint32 MetaFileSize() const { return (mMetaLocation & eFileSizeMask) >> eFileSizeOffset; }
void SetMetaFileSize(PRUint32 size)
{
mMetaLocation &= ~eFileSizeMask; // clear eFileSizeMask
mMetaLocation |= (size << eFileSizeOffset) & eFileSizeMask;
}
PRUint8 MetaFileGeneration() const
{
return (mMetaLocation & eFileGenerationMask);
}
void SetMetaFileGeneration( PRUint8 generation)
{
// clear everything, (separate file index = 0)
mMetaLocation = 0;
mMetaLocation |= generation & eFileGenerationMask;
mMetaLocation |= eLocationInitializedMask;
}
PRUint8 Generation() const
{
if ((mDataLocation & eLocationInitializedMask) &&
(DataFile() == 0))
return DataFileGeneration();
if ((mMetaLocation & eLocationInitializedMask) &&
(MetaFile() == 0))
return MetaFileGeneration();
return 0; // no generation
}
#if defined(IS_LITTLE_ENDIAN)
void Swap()
{
mHashNumber = htonl(mHashNumber);
mEvictionRank = htonl(mEvictionRank);
mDataLocation = htonl(mDataLocation);
mMetaLocation = htonl(mMetaLocation);
}
#endif
#if defined(IS_LITTLE_ENDIAN)
void Unswap()
{
mHashNumber = ntohl(mHashNumber);
mEvictionRank = ntohl(mEvictionRank);
mDataLocation = ntohl(mDataLocation);
mMetaLocation = ntohl(mMetaLocation);
}
#endif
};
/******************************************************************************
* nsDiskCacheRecordVisitor
*****************************************************************************/
enum { kDeleteRecordAndContinue = -1,
kStopVisitingRecords = 0,
kVisitNextRecord = 1
};
class nsDiskCacheRecordVisitor {
public:
virtual PRInt32 VisitRecord( nsDiskCacheRecord * mapRecord) = 0;
};
/******************************************************************************
* nsDiskCacheHeader
*****************************************************************************/
struct nsDiskCacheHeader {
PRUint32 mVersion; // cache version.
PRUint32 mDataSize; // size of cache in units of 1024bytes.
PRInt32 mEntryCount; // number of entries stored in cache.
PRUint32 mIsDirty; // dirty flag.
PRInt32 mRecordCount; // Number of records
PRUint32 mEvictionRank[kBuckets]; // Highest EvictionRank of the bucket
PRUint32 mBucketUsage[kBuckets]; // Number of used entries in the bucket
nsDiskCacheHeader()
: mVersion(nsDiskCache::kCurrentVersion)
, mDataSize(0)
, mEntryCount(0)
, mIsDirty(PR_TRUE)
, mRecordCount(0)
{}
void Swap()
{
#if defined(IS_LITTLE_ENDIAN)
mVersion = htonl(mVersion);
mDataSize = htonl(mDataSize);
mEntryCount = htonl(mEntryCount);
mIsDirty = htonl(mIsDirty);
mRecordCount = htonl(mRecordCount);
for (PRUint32 i = 0; i < kBuckets ; i++) {
mEvictionRank[i] = htonl(mEvictionRank[i]);
mBucketUsage[i] = htonl(mBucketUsage[i]);
}
#endif
}
void Unswap()
{
#if defined(IS_LITTLE_ENDIAN)
mVersion = ntohl(mVersion);
mDataSize = ntohl(mDataSize);
mEntryCount = ntohl(mEntryCount);
mIsDirty = ntohl(mIsDirty);
mRecordCount = ntohl(mRecordCount);
for (PRUint32 i = 0; i < kBuckets ; i++) {
mEvictionRank[i] = ntohl(mEvictionRank[i]);
mBucketUsage[i] = ntohl(mBucketUsage[i]);
}
#endif
}
};
/******************************************************************************
* nsDiskCacheMap
*****************************************************************************/
class nsDiskCacheMap {
public:
nsDiskCacheMap() :
mCacheDirectory(nsnull),
mMapFD(nsnull),
mRecordArray(nsnull),
mBufferSize(0),
mBuffer(nsnull),
mMaxRecordCount(16384) // this default value won't matter
{ }
~nsDiskCacheMap() {
(void) Close(PR_TRUE);
}
/**
* File Operations
*
* Open
*
* Creates a new cache map file if one doesn't exist.
* Returns error if it detects change in format or cache wasn't closed.
*/
nsresult Open( nsILocalFile * cacheDirectory);
nsresult Close(PRBool flush);
nsresult Trim();
nsresult FlushHeader();
nsresult FlushRecords( PRBool unswap);
void NotifyCapacityChange(PRUint32 capacity);
/**
* Record operations
*/
nsresult AddRecord( nsDiskCacheRecord * mapRecord, nsDiskCacheRecord * oldRecord);
nsresult UpdateRecord( nsDiskCacheRecord * mapRecord);
nsresult FindRecord( PRUint32 hashNumber, nsDiskCacheRecord * mapRecord);
nsresult DeleteRecord( nsDiskCacheRecord * mapRecord);
nsresult VisitRecords( nsDiskCacheRecordVisitor * visitor);
nsresult EvictRecords( nsDiskCacheRecordVisitor * visitor);
/**
* Disk Entry operations
*/
nsresult DeleteStorage( nsDiskCacheRecord * record);
nsresult GetFileForDiskCacheRecord( nsDiskCacheRecord * record,
PRBool meta,
nsIFile ** result);
nsresult GetLocalFileForDiskCacheRecord( nsDiskCacheRecord * record,
PRBool meta,
nsILocalFile ** result);
// On success, this returns the buffer owned by nsDiskCacheMap,
// so it must not be deleted by the caller.
nsDiskCacheEntry * ReadDiskCacheEntry( nsDiskCacheRecord * record);
nsresult WriteDiskCacheEntry( nsDiskCacheBinding * binding);
nsresult ReadDataCacheBlocks(nsDiskCacheBinding * binding, char * buffer, PRUint32 size);
nsresult WriteDataCacheBlocks(nsDiskCacheBinding * binding, char * buffer, PRUint32 size);
nsresult DeleteStorage( nsDiskCacheRecord * record, PRBool metaData);
/**
* Statistical Operations
*/
void IncrementTotalSize( PRUint32 delta)
{
mHeader.mDataSize += delta;
mHeader.mIsDirty = PR_TRUE;
}
void DecrementTotalSize( PRUint32 delta)
{
NS_ASSERTION(mHeader.mDataSize >= delta, "disk cache size negative?");
mHeader.mDataSize = mHeader.mDataSize > delta ? mHeader.mDataSize - delta : 0;
mHeader.mIsDirty = PR_TRUE;
}
inline void IncrementTotalSize( PRUint32 blocks, PRUint32 blockSize)
{
// Round up to nearest K
IncrementTotalSize(((blocks*blockSize) + 0x03FF) >> 10);
}
inline void DecrementTotalSize( PRUint32 blocks, PRUint32 blockSize)
{
// Round up to nearest K
DecrementTotalSize(((blocks*blockSize) + 0x03FF) >> 10);
}
PRUint32 TotalSize() { return mHeader.mDataSize; }
PRInt32 EntryCount() { return mHeader.mEntryCount; }
private:
/**
* Private methods
*/
nsresult OpenBlockFiles();
nsresult CloseBlockFiles(PRBool flush);
PRBool CacheFilesExist();
PRUint32 CalculateFileIndex(PRUint32 size);
nsresult GetBlockFileForIndex( PRUint32 index, nsILocalFile ** result);
PRUint32 GetBlockSizeForIndex( PRUint32 index) const {
return BLOCK_SIZE_FOR_INDEX(index);
}
// returns the bucket number
PRUint32 GetBucketIndex( PRUint32 hashNumber) const {
return (hashNumber & (kBuckets - 1));
}
// Gets the size of the bucket (in number of records)
PRUint32 GetRecordsPerBucket() const {
return mHeader.mRecordCount / kBuckets;
}
// Gets the first record in the bucket
nsDiskCacheRecord *GetFirstRecordInBucket(PRUint32 bucket) const {
return mRecordArray + bucket * GetRecordsPerBucket();
}
PRUint32 GetBucketRank(PRUint32 bucketIndex, PRUint32 targetRank);
PRInt32 VisitEachRecord(PRUint32 bucketIndex,
nsDiskCacheRecordVisitor * visitor,
PRUint32 evictionRank);
nsresult GrowRecords();
nsresult ShrinkRecords();
nsresult EnsureBuffer(PRUint32 bufSize);
// The returned structure will point to the buffer owned by nsDiskCacheMap,
// so it must not be deleted by the caller.
nsDiskCacheEntry * CreateDiskCacheEntry(nsDiskCacheBinding * binding,
PRUint32 * size);
/**
* data members
*/
private:
nsCOMPtr<nsILocalFile> mCacheDirectory;
PRFileDesc * mMapFD;
nsDiskCacheRecord * mRecordArray;
nsDiskCacheBlockFile mBlockFile[3];
PRUint32 mBufferSize;
char * mBuffer;
nsDiskCacheHeader mHeader;
PRInt32 mMaxRecordCount;
};
#endif // _nsDiskCacheMap_h_