/*************************************************************************
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * Copyright 2008 by Sun Microsystems, Inc.
 *
 * OpenOffice.org - a multi-platform office productivity suite
 *
 * $RCSfile: stgcache.cxx,v $
 * $Revision: 1.13 $
 *
 * This file is part of OpenOffice.org.
 *
 * OpenOffice.org is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 3
 * only, as published by the Free Software Foundation.
 *
 * OpenOffice.org is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License version 3 for more details
 * (a copy is included in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU Lesser General Public License
 * version 3 along with OpenOffice.org.  If not, see
 * <http://www.openoffice.org/license.html>
 * for a copy of the LGPLv3 License.
 *
 ************************************************************************/

// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_sot.hxx"

#if defined(_MSC_VER) && (_MSC_VER<1200)
#include <tools/presys.h>
#endif
#include <hash_map>
#if defined(_MSC_VER) && (_MSC_VER<1200)
#include <tools/postsys.h>
#endif
#include <vos/macros.hxx>

#include <string.h>
#include <osl/endian.h>
#include <tools/string.hxx>

#include "stg.hxx"
#include "stgelem.hxx"
#include "stgcache.hxx"
#include "stgstrms.hxx"
#include "stgdir.hxx"
#include "stgio.hxx"

/*************************************************************************/
//-----------------------------------------------------------------------------
typedef std::hash_map
<
    INT32,
    StgPage *,
    std::hash< INT32 >,
    NAMESPACE_STD(equal_to)< INT32 >
> UsrStgPagePtr_Impl;
#ifdef _MSC_VER
#pragma warning( disable: 4786 )
#endif

//#define   CHECK_DIRTY 1
//#define   READ_AFTER_WRITE 1

////////////////////////////// class StgPage /////////////////////////////
// This class implements buffer functionality. The cache will always return
// a page buffer, even if a read fails. It is up to the caller to determine
// the correctness of the I/O.

StgPage::StgPage( StgCache* p, short n )
{
    pCache = p;
    nData  = n;
    bDirty = FALSE;
    nPage  = 0;
    pData  = new BYTE[ nData ];
    pNext1 =
    pNext2 =
    pLast1 =
    pLast2 = NULL;
    pOwner = NULL;
}

StgPage::~StgPage()
{
    delete [] pData;
}

void StgPage::SetPage( short nOff, INT32 nVal )
{
    if( ( nOff < (short) ( nData / sizeof( INT32 ) ) ) && nOff >= 0 )
    {
#ifdef OSL_BIGENDIAN
      nVal = SWAPLONG(nVal);
#endif
        ((INT32*) pData )[ nOff ] = nVal;
        bDirty = TRUE;
    }
}

//////////////////////////////// class StgCache ////////////////////////////

// The disk cache holds the cached sectors. The sector type differ according
// to their purpose.

INT32 lcl_GetPageCount( ULONG nFileSize, short nPageSize )
{
//    return (nFileSize >= 512) ? (nFileSize - 512) / nPageSize : 0;
    // #i61980# reallife: last page may be incomplete, return number of *started* pages
    return (nFileSize >= 512) ? (nFileSize - 512 + nPageSize - 1) / nPageSize : 0;
}

StgCache::StgCache()
{
    nRef = 0;
    pStrm = NULL;
    pCur = pElem1 = NULL;
    nPageSize = 512;
    nError = SVSTREAM_OK;
    bMyStream = FALSE;
    bFile = FALSE;
    pLRUCache = NULL;
    pStorageStream = NULL;
}

StgCache::~StgCache()
{
    Clear();
    SetStrm( NULL, FALSE );
    delete (UsrStgPagePtr_Impl*)pLRUCache;
}

void StgCache::SetPhysPageSize( short n )
{
    nPageSize = n;
    ULONG nPos = pStrm->Tell();
    ULONG nFileSize = pStrm->Seek( STREAM_SEEK_TO_END );
    nPages = lcl_GetPageCount( nFileSize, nPageSize );
    pStrm->Seek( nPos );
}

// Create a new cache element
// pCur points to this element

StgPage* StgCache::Create( INT32 nPg )
{
    StgPage* pElem = new StgPage( this, nPageSize );
    pElem->nPage = nPg;
    // For data security, clear the buffer contents
    memset( pElem->pData, 0, pElem->nData );

    // insert to LRU
    if( pCur )
    {
        pElem->pNext1 = pCur;
        pElem->pLast1 = pCur->pLast1;
        pElem->pNext1->pLast1 =
        pElem->pLast1->pNext1 = pElem;
    }
    else
        pElem->pNext1 = pElem->pLast1 = pElem;
    if( !pLRUCache )
        pLRUCache = new UsrStgPagePtr_Impl();
    (*(UsrStgPagePtr_Impl*)pLRUCache)[pElem->nPage] = pElem;
    pCur = pElem;

    // insert to Sorted
    if( !pElem1 )
        pElem1 = pElem->pNext2 = pElem->pLast2 = pElem;
    else
    {
        StgPage* p = pElem1;
        do
        {
            if( pElem->nPage < p->nPage )
                break;
            p = p->pNext2;
        } while( p != pElem1 );
        pElem->pNext2 = p;
        pElem->pLast2 = p->pLast2;
        pElem->pNext2->pLast2 =
        pElem->pLast2->pNext2 = pElem;
        if( p->nPage < pElem1->nPage )
            pElem1 = pElem;
    }
    return pElem;
}

// Delete the given element

void StgCache::Erase( StgPage* pElem )
{
    //remove from LRU
    pElem->pNext1->pLast1 = pElem->pLast1;
    pElem->pLast1->pNext1 = pElem->pNext1;
    if( pCur == pElem )
        pCur = ( pElem->pNext1 == pElem ) ? NULL : pElem->pNext1;
    if( pLRUCache )
        ((UsrStgPagePtr_Impl*)pLRUCache)->erase( pElem->nPage );
    // remove from Sorted
    pElem->pNext2->pLast2 = pElem->pLast2;
    pElem->pLast2->pNext2 = pElem->pNext2;
    if( pElem1 == pElem )
        pElem1 = ( pElem->pNext2 == pElem ) ? NULL : pElem->pNext2;
    delete pElem;
}

// remove all cache elements without flushing them

void StgCache::Clear()
{
    StgPage* pElem = pCur;
    if( pCur ) do
    {
        StgPage* pDelete = pElem;
        pElem = pElem->pNext1;
        delete pDelete;
    }
    while( pCur != pElem );
    pCur = NULL;
    pElem1 = NULL;
    delete (UsrStgPagePtr_Impl*)pLRUCache;
    pLRUCache = NULL;
}

// Look for a cached page

StgPage* StgCache::Find( INT32 nPage )
{
    if( !pLRUCache )
        return NULL;
    UsrStgPagePtr_Impl::iterator aIt = ((UsrStgPagePtr_Impl*)pLRUCache)->find( nPage );
    if( aIt != ((UsrStgPagePtr_Impl*)pLRUCache)->end() )
    {
        // page found
        StgPage* pFound = (*aIt).second;

        if( pFound != pCur )
        {
            // remove from LRU
            pFound->pNext1->pLast1 = pFound->pLast1;
            pFound->pLast1->pNext1 = pFound->pNext1;
            // insert to LRU
            pFound->pNext1 = pCur;
            pFound->pLast1 = pCur->pLast1;
            pFound->pNext1->pLast1 =
            pFound->pLast1->pNext1 = pFound;
        }
        return pFound;
    }
    return NULL;
}

// Load a page into the cache

StgPage* StgCache::Get( INT32 nPage, BOOL bForce )
{
    StgPage* p = Find( nPage );
    if( !p )
    {
        p = Create( nPage );
        if( !Read( nPage, p->pData, 1 ) && bForce )
        {
            Erase( p );
            p = NULL;
            SetError( SVSTREAM_READ_ERROR );
        }
    }
    return p;
}

// Copy an existing page into a new page. Use this routine
// to duplicate an existing stream or to create new entries.
// The new page is initially marked dirty. No owner is copied.

StgPage* StgCache::Copy( INT32 nNew, INT32 nOld )
{
    StgPage* p = Find( nNew );
    if( !p )
        p = Create( nNew );
    if( nOld >= 0 )
    {
        // old page: we must have this data!
        StgPage* q = Get( nOld, TRUE );
        if( q )
            memcpy( p->pData, q->pData, p->nData );
    }
    p->SetDirty();
    return p;
}

// Flush the cache whose owner is given. NULL flushes all.

BOOL StgCache::Commit( StgDirEntry* )
{
    StgPage* p = pElem1;
    if( p ) do
    {
        if( p->bDirty )
        {
            BOOL b = Write( p->nPage, p->pData, 1 );
            if( !b )
                return FALSE;
            p->bDirty = FALSE;
        }
        p = p->pNext2;
    } while( p != pElem1 );
    pStrm->Flush();
    SetError( pStrm->GetError() );
#ifdef CHECK_DIRTY
    p = pElem1;
    if( p ) do
    {
        if( p->bDirty )
        {
            ErrorBox( NULL, WB_OK, String("SO2: Dirty Block in Ordered List") ).Execute();
            BOOL b = Write( p->nPage, p->pData, 1 );
            if( !b )
                return FALSE;
            p->bDirty = FALSE;
        }
        p = p->pNext2;
    } while( p != pElem1 );
    p = pElem1;
    if( p ) do
    {
        if( p->bDirty )
        {
            ErrorBox( NULL, WB_OK, String("SO2: Dirty Block in LRU List") ).Execute();
            BOOL b = Write( p->nPage, p->pData, 1 );
            if( !b )
                return FALSE;
            p->bDirty = FALSE;
        }
        p = p->pNext1;
    } while( p != pElem1 );
#endif
    return TRUE;
}

void StgCache::Revert( StgDirEntry* )
{}

// Set a stream

void StgCache::SetStrm( SvStream* p, BOOL bMy )
{
    if( pStorageStream )
    {
        pStorageStream->ReleaseRef();
        pStorageStream = NULL;
    }

    if( bMyStream )
        delete pStrm;
    pStrm = p;
    bMyStream = bMy;
}

void StgCache::SetStrm( UCBStorageStream* pStgStream )
{
    if( pStorageStream )
        pStorageStream->ReleaseRef();
    pStorageStream = pStgStream;

    if( bMyStream )
        delete pStrm;

    pStrm = NULL;

    if ( pStorageStream )
    {
        pStorageStream->AddRef();
        pStrm = pStorageStream->GetModifySvStream();
    }

    bMyStream = FALSE;
}

// Open/close the disk file

BOOL StgCache::Open( const String& rName, StreamMode nMode )
{
    // do not open in exclusive mode!
    if( nMode & STREAM_SHARE_DENYALL )
        nMode = ( ( nMode & ~STREAM_SHARE_DENYALL ) | STREAM_SHARE_DENYWRITE );
    SvFileStream* pFileStrm = new SvFileStream( rName, nMode );
    // SvStream "Feature" Write Open auch erfolgreich, wenns nicht klappt
    BOOL bAccessDenied = FALSE;
    if( ( nMode & STREAM_WRITE ) && !pFileStrm->IsWritable() )
    {
        pFileStrm->Close();
        bAccessDenied = TRUE;
    }
    SetStrm( pFileStrm, TRUE );
    if( pFileStrm->IsOpen() )
    {
        ULONG nFileSize = pStrm->Seek( STREAM_SEEK_TO_END );
        nPages = lcl_GetPageCount( nFileSize, nPageSize );
        pStrm->Seek( 0L );
    }
    else
        nPages = 0;
    bFile = TRUE;
    SetError( bAccessDenied ? ERRCODE_IO_ACCESSDENIED : pStrm->GetError() );
    return Good();
}

void StgCache::Close()
{
    if( bFile )
    {
        ((SvFileStream*) pStrm)->Close();
        SetError( pStrm->GetError() );
    }
}

// low level I/O

BOOL StgCache::Read( INT32 nPage, void* pBuf, INT32 nPg )
{
    if( Good() )
    {
        /*  #i73846# real life: a storage may refer to a page one-behind the
            last valid page (see document attached to the issue). In that case
            (if nPage==nPages), just do nothing here and let the caller work on
            the empty zero-filled buffer. */
        if ( nPage > nPages )
            SetError( SVSTREAM_READ_ERROR );
        else if ( nPage < nPages )
        {
            ULONG nPos = Page2Pos( nPage );
            INT32 nPg2 = ( ( nPage + nPg ) > nPages ) ? nPages - nPage : nPg;
            ULONG nBytes = nPg2 * nPageSize;
            // fixed address and size for the header
            if( nPage == -1 )
            {
                nPos = 0L, nBytes = 512;
                nPg2 = nPg;
            }
            if( pStrm->Tell() != nPos )
            {
                if( pStrm->Seek( nPos ) != nPos ) {
    #ifdef CHECK_DIRTY
                    ErrorBox( NULL, WB_OK, String("SO2: Seek failed") ).Execute();
    #endif
                }
            }
            pStrm->Read( pBuf, nBytes );
            if ( nPg != nPg2 )
                SetError( SVSTREAM_READ_ERROR );
            else
                SetError( pStrm->GetError() );
        }
    }
    return Good();
}

BOOL StgCache::Write( INT32 nPage, void* pBuf, INT32 nPg )
{
    if( Good() )
    {
        ULONG nPos = Page2Pos( nPage );
        ULONG nBytes = nPg * nPageSize;
        // fixed address and size for the header
        if( nPage == -1 )
            nPos = 0L, nBytes = 512;
        if( pStrm->Tell() != nPos )
        {
            if( pStrm->Seek( nPos ) != nPos ) {
#ifdef CHECK_DIRTY
                ErrorBox( NULL, WB_OK, String("SO2: Seek failed") ).Execute();
#endif
            }
        }
        ULONG nRes = pStrm->Write( pBuf, nBytes );
        if( nRes != nBytes )
            SetError( SVSTREAM_WRITE_ERROR );
        else
            SetError( pStrm->GetError() );
#ifdef READ_AFTER_WRITE
        BYTE cBuf[ 512 ];
        pStrm->Flush();
        pStrm->Seek( nPos );
        BOOL bRes = ( pStrm->Read( cBuf, 512 ) == 512 );
        if( bRes )
            bRes = !memcmp( cBuf, pBuf, 512 );
        if( !bRes )
        {
            ErrorBox( NULL, WB_OK, String("SO2: Read after Write failed") ).Execute();
            pStrm->SetError( SVSTREAM_WRITE_ERROR );
        }
#endif
    }
    return Good();
}

// set the file size in pages

BOOL StgCache::SetSize( INT32 n )
{
    // Add the file header
    INT32 nSize = n * nPageSize + 512;
    pStrm->SetStreamSize( nSize );
    SetError( pStrm->GetError() );
    if( !nError )
        nPages = n;
    return Good();
}

void StgCache::SetError( ULONG n )
{
    if( n && !nError )
        nError = n;
}

void StgCache::ResetError()
{
    nError = SVSTREAM_OK;
    pStrm->ResetError();
}

void StgCache::MoveError( StorageBase& r )
{
    if( nError != SVSTREAM_OK )
    {
        r.SetError( nError );
        ResetError();
    }
}

// Utility functions

INT32 StgCache::Page2Pos( INT32 nPage )
{
    if( nPage < 0 ) nPage = 0;
    return( nPage * nPageSize ) + nPageSize;
}

INT32 StgCache::Pos2Page( INT32 nPos )
{
    return ( ( nPos + nPageSize - 1 ) / nPageSize ) * nPageSize - 1;
}