1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/kernelhwsrv/userlibandfileserver/fileserver/sfat32/inc/sl_fatcache32.h Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,240 @@
1.4 +// Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
1.5 +// All rights reserved.
1.6 +// This component and the accompanying materials are made available
1.7 +// under the terms of the License "Eclipse Public License v1.0"
1.8 +// which accompanies this distribution, and is available
1.9 +// at the URL "http://www.eclipse.org/legal/epl-v10.html".
1.10 +//
1.11 +// Initial Contributors:
1.12 +// Nokia Corporation - initial contribution.
1.13 +//
1.14 +// Contributors:
1.15 +//
1.16 +// Description:
1.17 +// f32\sfat32\inc\sl_facache32.h
1.18 +// FAT32 various cache classes definition
1.19 +//
1.20 +//
1.21 +
1.22 +/**
1.23 + @file
1.24 + @internalTechnology
1.25 +*/
1.26 +
1.27 +#ifndef SL_FAT_CACHE_32_H
1.28 +#define SL_FAT_CACHE_32_H
1.29 +
1.30 +#include "sl_fatcache.h"
1.31 +
1.32 +class CFat32LruCachePage;
1.33 +
1.34 +
1.35 +//---------------------------------------------------------------------------------------------------------------------------------
1.36 +
1.37 +/**
1.38 + FAT32 LRU paged cache. Used for FAT32 only.
1.39 +
1.40 + Consists of LRU list of cache pages; Each page is logically divided to page sectors. The number of pages depends on the
1.41 + maximal amount of memory this cache allowed to use. Usually, whole FAT32 can not be cached fully because of its large size.
1.42 + So, this type caches the most receinlly used areas of the FAT32. This is the wriite-back cache.
1.43 +
1.44 + Read granularity: One page, which size is 2^aRdGranularityLog2
1.45 + Write granularity: cache's page sector; its size is 2^aWrGranularityLog2
1.46 +*/
1.47 +class CFat32LruCache : public CFatPagedCacheBase
1.48 +{
1.49 + public:
1.50 +
1.51 + static CFat32LruCache* NewL(CFatMountCB* aOwner, TUint32 aMaxMemSize, TUint32 aRdGranularityLog2, TUint32 aWrGranularityLog2);
1.52 +
1.53 + //-- overrides from base class
1.54 + virtual void Close(TBool aDiscardDirtyData);
1.55 + virtual void FlushL();
1.56 +
1.57 + virtual TUint32 ReadEntryL(TUint32 aIndex);
1.58 + virtual void WriteEntryL(TUint32 aIndex, TUint32 aEntry);
1.59 +
1.60 + virtual TInt Invalidate();
1.61 + virtual TInt InvalidateRegion(TUint32 aStartEntry, TUint32 aNumEntries);
1.62 +
1.63 +
1.64 + virtual CFatBitCache* BitCacheInterface();
1.65 +
1.66 + public:
1.67 + TBool FindFreeEntryInCacheSectorL(TUint32& aFatEntryIndex);
1.68 +
1.69 + private:
1.70 +
1.71 + void InitialiseL(CFatMountCB* aOwner, TUint32 aFatSize, TUint32 aRdGranularityLog2, TUint32 aWrGranularityLog2);
1.72 +
1.73 + CFat32LruCache();
1.74 + CFat32LruCache(const CFat32LruCache&);
1.75 + CFat32LruCache& operator=(const CFat32LruCache&);
1.76 +
1.77 + TBool ReadCachedEntryL(TUint32 aFatIndex, TFat32Entry& aResult);
1.78 + TBool WriteCachedEntryL(TUint32 aFatIndex, TFat32Entry aFatEntry);
1.79 +
1.80 + CFat32LruCachePage* DoGetSpareCachePageL();
1.81 +
1.82 + void AssertCacheReallyClean() ;
1.83 +
1.84 + private:
1.85 +
1.86 + typedef TDblQue<CFat32LruCachePage> TPageList;
1.87 + typedef TDblQueIter<CFat32LruCachePage> TPageIterator;
1.88 +
1.89 + TUint32 iMaxFatEntries; ///< maximal number of FAT entries in FAT table
1.90 + TUint iNumPagesAllocated; ///< number of pages currently allocated
1.91 + TUint iMaxPages; ///< maximal pages allowed to allocate
1.92 + TPageList iPageList; ///< LRU list of cache pages.
1.93 +
1.94 +
1.95 + CFatBitCache *iBitCache; ///< pointer to the FAT bit supercache
1.96 +
1.97 +};
1.98 +
1.99 +
1.100 +//---------------------------------------------------------------------------------------------------------------------------------
1.101 +
1.102 +/**
1.103 + FAT32 LRU cache page. Used only by CFat32LruCache.
1.104 +*/
1.105 +class CFat32LruCachePage : public CFatCachePageBase
1.106 +{
1.107 + public:
1.108 +
1.109 + static CFat32LruCachePage* NewL(CFatPagedCacheBase& aCache);
1.110 +
1.111 + //-- overrides
1.112 + virtual TBool ReadCachedEntryL (TUint32 aFatIndex, TUint32& aResult);
1.113 + virtual TBool WriteCachedEntryL(TUint32 aFatIndex, TUint32 aFatEntry);
1.114 + virtual TUint32 ReadFromMediaL(TUint32 aFatIndex);
1.115 + //----
1.116 +
1.117 + private:
1.118 + CFat32LruCachePage(CFatPagedCacheBase& aCache);
1.119 +
1.120 + //-- outlaws here
1.121 + CFat32LruCachePage();
1.122 + CFat32LruCachePage(const CFat32LruCachePage&);
1.123 + CFat32LruCachePage& operator=(const CFat32LruCachePage&);
1.124 +
1.125 + inline TFat32Entry* GetEntryPtr(TUint32 aFatIndex) const;
1.126 + virtual void DoWriteSectorL(TUint32 aSector);
1.127 +
1.128 + private:
1.129 + enum {KFat32EntryMask = 0x0FFFFFFF}; ///< FAT32 entry mask
1.130 +
1.131 + public:
1.132 + TDblQueLink iLink; ///< list link object. See TPageList
1.133 +};
1.134 +
1.135 +//---------------------------------------------------------------------------------------------------------------------------------
1.136 +
1.137 +/**
1.138 + FAT32 bit supercache. This is a special cache above the CFat32LruCache.
1.139 + Used for quick lookup for the free entries in FAT32 table without accessing media and thrashing FAT32 LRU cache.
1.140 +
1.141 + Logically consists of a bit vector, where each bit represents one FAT sector (one unit of read granularity within CFat32LruCachePage)
1.142 + for the _whole_ FAT table.
1.143 +
1.144 + If some bit in the vector is set to '1' it means that the corresponding FAT cache sector (not necessarily currently cached) _may_ have
1.145 + a at least one free FAT entry. If the bit is '0' it means that there is no free fat entries in this part of the FAT.
1.146 +
1.147 + The situation when bit set to '1' corresponds to the FAT cache sector without free entries is quite possible, but it is resolved by this cache.
1.148 + The situation when '0' bit corresponds to the fat sector that _does_ contain free entries is extremely unlikely and can be
1.149 + caused by direct raw writes to the FAT, for example. Nothing terribly wrong with this situation, the search for free entry will fall back
1.150 + to the old algorithm CFatTable::FindClosestFreeClusterL() .
1.151 +
1.152 + The information in this cache is also updated on flushing dirty sectros by CFat32LruCachePage.
1.153 +
1.154 +
1.155 +*/
1.156 +class CFatBitCache : public CBase
1.157 +{
1.158 + public:
1.159 +
1.160 + ~CFatBitCache();
1.161 +
1.162 + static CFatBitCache* New(CFat32LruCache& aOnwerFatCache);
1.163 +
1.164 + void Close();
1.165 +
1.166 + TBool StartPopulating();
1.167 + TBool FinishPopulating(TBool aSuccess);
1.168 +
1.169 +
1.170 + /** possible states of this cache */
1.171 + enum TState
1.172 + {
1.173 + EInvalid, ///< initial, invalid
1.174 + ENotPopulated, ///< initialised, but not populated yet
1.175 + EPopulating, ///< in the process of populating
1.176 + EPopulated, ///< successfully populated; the only consistent state.
1.177 + };
1.178 +
1.179 + inline TState State() const;
1.180 + inline TBool UsableState() const;
1.181 + inline TBool FatSectorHasFreeEntry(TUint32 aFatSectorNum) const;
1.182 + inline void SetFreeEntryInFatSector(TUint32 aFatSectorNum, TBool aHasFreeEntry);
1.183 +
1.184 + TBool SetFreeFatEntry(TUint32 aFatIndex);
1.185 + TInt FindClosestFreeFatEntry(TUint32& aFatIndex);
1.186 + void MarkFatRange(TUint32 aStartFatIndex, TUint32 aEndFatIndex, TBool aAsFree);
1.187 +
1.188 +
1.189 + void Dump() const;
1.190 +
1.191 + private:
1.192 +
1.193 + //-- outlaws
1.194 + CFatBitCache();
1.195 + CFatBitCache(const CFatBitCache&);
1.196 + CFatBitCache& operator=(const CFatBitCache&);
1.197 +
1.198 + CFatBitCache(CFat32LruCache& aOnwerFatCache);
1.199 +
1.200 + TInt Initialise();
1.201 +
1.202 + inline void SetState(TState aState);
1.203 + inline TUint32 FatIndexToCacheSectorNumber(TUint32 aFatIndex) const;
1.204 + inline TUint32 CacheSectorNumberToFatIndex(TUint32 aCacheSecNum) const;
1.205 +
1.206 + private:
1.207 +
1.208 + TState iState; ///< internal state of the cache
1.209 + RBitVector iBitCache; ///< bit vector itself
1.210 + TUint32 iFatIdxToSecCoeff; ///< Log2(FatCacheSectorSize/Sizeof(FAT32 entry)). Used to convert FAT32 index to FAT32 cache sector number and back.
1.211 + CFat32LruCache& iOwnerFatCache; ///< reference to the owner FAT32 LRU cache
1.212 +
1.213 + DBG_STATEMENT(TUint iPopulatingThreadId;) ///< used in debug mode for checking multithreading issues
1.214 +};
1.215 +
1.216 +//---------------------------------------------------------------------------------------------------------------------------------
1.217 +
1.218 +#include "sl_fatcache32.inl"
1.219 +
1.220 +#endif //SL_FAT_CACHE_32_H
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