diff -r a41df078684a -r 4122176ea935 userlibandfileserver/fileserver/sfat32/sl_cache.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/userlibandfileserver/fileserver/sfat32/sl_cache.cpp	Mon Dec 21 16:14:42 2009 +0000
@@ -0,0 +1,555 @@
+// Copyright (c) 1996-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of the License "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// f32\sfat\sl_cache.cpp
+// 
+//
+
+#include "sl_std.h"
+#include "sl_cache.h"
+
+//---------------------------------------------------------------------------------------------------------------------------------
+
+/**
+    CWTCachePage factory function.    
+    @param  aPageSizeLog2 Log2(cache page size in bytes)
+    @return a pointer to the created object.
+*/
+CWTCachePage* CWTCachePage::NewL(TUint32 aPageSizeLog2)
+    {
+    CWTCachePage* pSelf = new (ELeave)CWTCachePage;
+    pSelf->ConstructL(aPageSizeLog2);
+
+    return pSelf;
+    }
+
+/**
+    2nd stage constructor.
+    @param  aPageSizeLog2 Log2(cache page size in bytes)
+*/
+void CWTCachePage::ConstructL(TUint32 aPageSizeLog2)
+    {
+    iData.CreateMaxL(1 << aPageSizeLog2);
+    }
+
+CWTCachePage::CWTCachePage()
+    {
+    iStartPos = 0xDeadDeadul;
+    iValid  = 0;
+    }
+
+CWTCachePage::~CWTCachePage() 
+    { 
+    iData.Close(); 
+    }
+
+
+
+//---------------------------------------------------------------------------------------------------------------------------------
+
+CMediaWTCache::CMediaWTCache(TFatDriveInterface& aDrive)
+          :iDrive(aDrive), iPageSizeLog2(0), iAllPagesValid(EFalse)
+    {
+    iCacheDisabled = EFalse;
+    iCacheBasePos  = 0; 
+    }
+
+CMediaWTCache::~CMediaWTCache()
+    {
+    //-- delete pages
+    TInt cnt = iPages.Count();
+    while(cnt--)
+        {
+        delete iPages[cnt];
+        }
+
+    iPages.Close();
+    }
+
+
+/**
+    Directory cache factory function.
+
+    @param  aDrive  reference to the driver for media access.
+    @param  aNumPages     number of cache pages to be created
+    @param  aPageSizeLog2 Log2 of the page size in bytes
+    
+    @return a pointer to the created object.
+*/
+CMediaWTCache* CMediaWTCache::NewL(TFatDriveInterface& aDrive, TUint32 aNumPages, TUint32 aPageSizeLog2)
+    {
+#ifndef ENABLE_DEDICATED_DIR_CACHE    
+    //-- dedicated directory cache isn't enabled
+    (void)aDrive; //-- supress compiler's warning
+    (void)aClusterSizeLog2;
+    return NULL;
+#else    
+
+    //-- dedicated directory cache is enabled, create it
+    ASSERT(aPageSizeLog2);
+    ASSERT(aNumPages);
+
+    CMediaWTCache* pSelf = new (ELeave) CMediaWTCache(aDrive);
+    
+    CleanupStack::PushL(pSelf);
+    pSelf->ConstructL(aNumPages, aPageSizeLog2);
+    CleanupStack::Pop();
+
+    return pSelf;
+
+#endif
+    }
+
+/**
+    2nd stage constructor.
+    @param  aNumPages number of pages in the directory cache.
+    @param  aPageSizeLog2 Log2(single cache page size in bytes)
+*/
+void CMediaWTCache::ConstructL(TUint32 aNumPages, TUint32 aPageSizeLog2)
+    {
+    ASSERT(aNumPages && aPageSizeLog2);
+    
+    __PRINT2(_L("#CMediaWTCache::CreateL() Pages=%d, PageSize=%d"), aNumPages, 1<<aPageSizeLog2);
+    
+    iPageSizeLog2 = aPageSizeLog2; 
+
+    //-- create cache pages
+    for(TUint cnt=0; cnt<aNumPages; ++cnt)
+        {
+        CWTCachePage* pPage = CWTCachePage::NewL(aPageSizeLog2);
+        iPages.Append(pPage);
+        }
+
+    InvalidateCache();  
+    }
+
+
+/**
+    @return size of the cache in bytes. Can be 0.
+*/
+TUint32 CMediaWTCache::CacheSizeInBytes() const
+    {
+    const TUint32 cacheSz = iPages.Count() << iPageSizeLog2; //-- Page size is always power of 2
+    return cacheSz;
+    }
+
+/**
+Implementation of pure virtual function.
+@see MWTCacheInterface::MakePageMRU()
+*/
+void CMediaWTCache::MakePageMRU(TInt64 /*aPos*/)
+	{
+	return;
+	}
+
+/**
+Implementation of pure virtual function.
+@see MWTCacheInterface::PageSizeInBytesLog2()
+*/
+TUint32 CMediaWTCache::PageSizeInBytesLog2() const
+	{
+	return iPageSizeLog2;
+	}
+
+/**
+    Control method.
+
+    @param  aFunction   control function
+    @param  aParam1     just arbitrary parameter 
+    @param  aParam2     just arbitrary parameter 
+    @return Standard error code.
+*/
+
+TInt CMediaWTCache::Control(TUint32 aFunction, TUint32 aParam1, TAny* /*aParam2*/)
+    {
+    TInt nRes = KErrNotSupported;
+
+#ifdef _DEBUG
+    switch(aFunction)
+        {
+        //-- disable / enable cache, for debug
+        //-- if aParam1 !=0 cache will be disabled, enabled otherwise
+        case EDisableCache: 
+            iCacheDisabled = aParam1 ? 1 : 0;
+            nRes = KErrNone;
+        break;
+
+        case EDumpCache:
+        break;
+           
+        case ECacheInfo:
+        break;
+   
+        default:
+            __PRINT1(_L("CMediaWTCache::Control() invalid function: %d"), aFunction);
+            ASSERT(0);
+        break;
+        }
+#else
+    (void)aFunction; //-- supress warnings
+    (void)aParam1;
+    User::Invariant(); //-- don't call this method in release build
+#endif //_DEBUG   
+    
+    return nRes;
+    }
+
+//-------------------------------------------------------------------------------------
+/**
+    Invalidate whole cache
+*/
+void CMediaWTCache::InvalidateCache(void)
+    {
+    const TUint nPages = iPages.Count();    
+    for(TUint i=0; i<nPages; ++i)
+        {
+        iPages[i]->iValid=EFalse;
+        }
+
+    iAllPagesValid = EFalse;
+    }
+
+//-------------------------------------------------------------------------------------
+/** 
+    invalidate a single cache page if the aPos is cached (belongs to some page)
+    If the cache user wants to invalidate some media address range, it will have to calculate 
+    pages positions itself. The best way to do this - is to write another method that takes lenght of the 
+    region being invalidated. 
+
+    @param aPos media position. If it is cached, the corresponding single cache page will be marked as invalid
+*/
+void CMediaWTCache::InvalidateCachePage(TUint64 aPos)
+    {
+    const TUint nPages = iPages.Count();    
+    for(TUint i=0; i<nPages; ++i)
+        {
+        if( iPages[i]->PosCached(aPos))  
+            {
+            iPages[i]->iValid=EFalse;
+            iAllPagesValid = EFalse;
+            break;
+            }
+        }
+
+    }
+
+//-------------------------------------------------------------------------------------
+
+/**
+    Find cache page by given media position.
+    
+    @param  aPos    linear media position
+    @return positive cache page number or -1 if no pages containing data at aPos found.
+*/
+TInt CMediaWTCache::FindPageByPos(TInt64 aPos) const
+    {
+    const TUint nPages = iPages.Count();    
+    for(TUint i=0; i<nPages; ++i)
+        {
+        if( iPages[i]->PosCached(aPos))  
+            return i; 
+        }
+
+    return KErrNotFound;
+    }
+
+/**
+    Push given page aPageNo to the 1st position in the pages array. Used for LRU mechanism
+    
+    @param  aPageNo page number to be made LRU
+*/
+void CMediaWTCache::MakePageLRU(TInt aPageNo)
+    {
+    ASSERT(aPageNo >=0);
+
+    if(aPageNo <= 0)
+        return; //-- nothing to do
+    
+    const TInt nPages = iPages.Count();
+    ASSERT(aPageNo < nPages);
+
+    if(aPageNo < nPages)
+        {
+        CWTCachePage* pPage=iPages[aPageNo];
+    
+        iPages.Remove(aPageNo);
+        iPages.Insert(pPage,0); //-- insert the pointer to the 1st position in the array
+        ASSERT(nPages == iPages.Count());
+        }
+    }
+
+/*
+    Find a spare page or evict the last from LRU list
+    
+    @return page number
+*/
+TUint32  CMediaWTCache::GrabPage() const
+    {
+    const TUint nPages = iPages.Count();
+
+    if(!iAllPagesValid)
+        {//-- try to find unused cache page
+        for(TUint i=0; i<nPages; ++i)
+            {
+            if(! iPages[i]->iValid)
+                return i; //-- found unused page
+            }
+        }
+
+    //-- no spare pages, evict the last one, it shall be last used
+    iAllPagesValid = ETrue;
+    return nPages-1;
+    }
+
+/*
+    Find a spare page or evict the last from LRU list, then read data to this page from media starting from aPos
+    
+    @param  aPos    media linear position from where the data will be read to the page
+    @return cache page number
+*/
+TUint32 CMediaWTCache::GrabReadPageL(TInt64 aPos)
+    {
+    //-- find a spare or page to evict
+    TUint nPage = GrabPage();
+    CWTCachePage& page = *iPages[nPage]; 
+
+    //-- read data to this page
+    page.iStartPos = CalcPageStartPos(aPos);
+    
+    __PRINT4(_L("#CMediaWTCache::GrabReadPageL() Reading page:%d, Pos=0x%x, PageStartPos=0x%x, page=0x%X"),nPage, (TUint32)aPos, (TUint32)page.iStartPos, iPages[nPage]);
+        
+    const TInt nErr = iDrive.ReadNonCritical(page.iStartPos, PageSize(), page.iData);
+    if(nErr !=KErrNone)
+        {//-- some serious problem occured during reading, invalidate cache.
+        InvalidateCache();
+        User::Leave(nErr);
+        }
+    
+    page.iValid = ETrue;
+
+    return nPage;
+    }
+
+/**
+    Try to find the page with cached data at "aPos" media position.
+    If such page found, returns its number, otherwise takes least recently used page and reads data there.
+    
+    @param  aPos    media linear position to find in the cache
+    @return cache page number
+
+*/
+TUint32 CMediaWTCache::FindOrGrabReadPageL(TInt64 aPos)
+    {
+    //-- find out if aPos is in cache
+    TInt nPage=FindPageByPos(aPos);
+    
+    if(nPage < 0)
+        {//-- no page contains data to read
+        nPage = GrabReadPageL(aPos); //-- find a spare page and read data into it
+        }
+
+    return nPage;
+    }
+
+/**
+    Finds out if the media position "aPosToSearch" is in the cache and returns cache page information in this case.
+
+    @param  aPosToSearch    linear media position to lookup in the cache
+    @param  aCachedPosStart if "aPosToSearch" is cached, here will be media position of this page start
+    
+    @return 0 if aPosToSearch isn't cached, otherwise  cache page size in bytes (see also aCachedPosStart).
+*/
+TUint32 CMediaWTCache::PosCached(const TInt64& aPosToSearch, TInt64& aCachedPosStart)
+    {
+    TInt nPage = FindPageByPos(aPosToSearch);
+    if(nPage <0 )
+        return 0; //-- cache page containing aPos not found
+
+    aCachedPosStart = iPages[nPage]->iStartPos;
+    
+    return PageSize();
+    }
+
+/**
+    Read data from the media through the directory cache.
+    
+    @param  aPos    linear media position to start reading with
+    @param  aLength how many bytes to read
+    @param  aDes    data will be placed there
+*/
+void CMediaWTCache::ReadL(TInt64 aPos,TInt aLength,TDes8& aDes)
+    {
+    
+#ifdef _DEBUG
+    if(iCacheDisabled)
+        {//-- cache is disabled for debug purposes
+        User::LeaveIfError(iDrive.ReadNonCritical(aPos, aLength, aDes));
+        return;
+        }
+#endif //_DEBUG
+
+    const TUint32 PageSz = PageSize();//-- cache page size
+
+    //-- find out if aPos is in cache. If not, find a spare page and read data there
+    TInt nPage = FindOrGrabReadPageL(aPos);
+    CWTCachePage* pPage = iPages[nPage];
+
+    const TUint32 bytesToPageEnd = (TUint32)(pPage->iStartPos+PageSz - aPos); //-- number of bytes from aPos to the end of the page
+
+//    __PRINT5(_L("CMediaWTCache::ReadL: aPos=%lx, aLength=%x, page:%lx, pageSz:%x, bytesToPageEnd=%x"), aPos, aLength, pPage->iStartPos, PageSz, bytesToPageEnd);
+    if((TUint32)aLength <= bytesToPageEnd) 
+        {//-- the data section is in the cache page entirely, take data directly from the cache
+        aDes.Copy(pPage->PtrInCachePage(aPos), aLength);
+        }
+    else
+        {//-- Data to be read cross cache page boundary or probably we have more than 1 page to read
+
+        TUint32 dataLen(aLength);   //-- current data length
+        TInt64  currMediaPos(aPos); //-- current media position
+
+        //-- 1. read data that are already in the current page
+        aDes.Copy(pPage->PtrInCachePage(currMediaPos), bytesToPageEnd);
+
+        dataLen -= bytesToPageEnd;
+        currMediaPos += bytesToPageEnd;
+
+        //-- 2. read whole pages of data
+        while(dataLen >= PageSz)
+            {
+            nPage = FindOrGrabReadPageL(currMediaPos); //-- find out if currMediaPos is in cache. If not, find a spare page and read data there
+            pPage = iPages[nPage];
+
+            aDes.Append(pPage->PtrInCachePage(currMediaPos),PageSz);
+        
+            dataLen -= PageSz;
+            currMediaPos += PageSz;
+        
+            MakePageLRU(nPage); //-- push the page to the top of the priority list
+            }
+
+        //-- 3. read the rest of the data
+        if(dataLen >0)
+            {
+            nPage = FindOrGrabReadPageL(currMediaPos); //-- find out if currMediaPos is in cache. If not, find a spare page and read data there
+            pPage = iPages[nPage];
+
+            aDes.Append(pPage->PtrInCachePage(currMediaPos), dataLen);
+            }
+
+        } //else((TUint32)aLength <= bytesToPageEnd) 
+
+
+    MakePageLRU(nPage); //-- push the page to the top of the priority list
+    
+    }
+
+/**
+    Write data to the media through the directory cache.
+    
+    @param  aPos    linear media position to start writing with
+    @param  aDes    data to write
+*/
+void CMediaWTCache::WriteL(TInt64 aPos,const TDesC8& aDes)
+    {
+
+#ifdef _DEBUG
+    if(iCacheDisabled)
+        {//-- cache is disabled for debug purposes
+        User::LeaveIfError(iDrive.WriteCritical(aPos,aDes));
+        return;
+        }
+#endif //_DEBUG
+
+          TUint32 dataLen = aDes.Size();
+    const TUint8* pData   = aDes.Ptr();
+    const TUint32 PageSz  = PageSize(); //-- cache page size
+
+    //-- find out if aPos is in cache. If not, find a spare page and read data there
+    TInt nPage = FindOrGrabReadPageL(aPos);
+    CWTCachePage* pPage = iPages[nPage];
+
+    const TUint32 bytesToPageEnd = (TUint32)(pPage->iStartPos+PageSize() - aPos); //-- number of bytes from aPos to the end of the page
+//    __PRINT5(_L("CMediaWTCache::WriteL: aPos=%lx, aLength=%x, page:%lx, pageSz:%x, bytesToPageEnd=%x"), aPos, dataLen, pPage->iStartPos, PageSz, bytesToPageEnd);
+    if(dataLen <= bytesToPageEnd)
+        {//-- data section completely fits to the cache page
+        Mem::Copy(pPage->PtrInCachePage(aPos), pData, dataLen);   //-- update cache
+        }
+    else
+        {//-- Data to be written cross cache page boundary or probably we have more than 1 page to write
+
+        TInt64  currMediaPos(aPos); //-- current media position
+
+        //-- 1. update the current page
+        Mem::Copy(pPage->PtrInCachePage(currMediaPos), pData, bytesToPageEnd);
+
+        pData += bytesToPageEnd;
+        currMediaPos += bytesToPageEnd;
+        dataLen -= bytesToPageEnd;
+
+        //-- 2. write whole pages of data to the cache
+        while(dataLen >= PageSz)
+            {
+            nPage = FindPageByPos(currMediaPos); //-- ?? shall we read data there ??
+            if(nPage >=0)
+                {
+                pPage = iPages[nPage];
+                Mem::Copy(pPage->PtrInCachePage(currMediaPos), pData, PageSz);
+                MakePageLRU(nPage); //-- push the page to the top of the priority list
+                }
+            else
+                nPage=0;
+
+            pData += PageSz;
+            currMediaPos += PageSz;
+            dataLen -= PageSz;
+            }
+
+        //-- 3. write the rest of the data
+        if(dataLen)
+            {
+            nPage = FindOrGrabReadPageL(currMediaPos); //-- find out if currMediaPos is in cache. If not, find a spare page and read data there
+            pPage = iPages[nPage];
+
+            Mem::Copy(pPage->PtrInCachePage(currMediaPos), pData, dataLen);
+            }
+
+        }// else(dataLen <= bytesToPageEnd)
+
+    
+    //-- write data to the media
+    const TInt nErr = iDrive.WriteCritical(aPos,aDes); 
+    if(nErr != KErrNone)
+        {//-- some serious problem occured during writing, invalidate cache.
+        InvalidateCache();
+        User::Leave(nErr);
+        }
+
+    MakePageLRU(nPage); //-- push the page to the top of the priority list
+    }
+
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