source/sdstor/stgdir.cxx

/**************************************************************
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *************************************************************/


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

#include <string.h>     // memcpy()

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


//////////////////////////// class StgDirEntry /////////////////////////////

// This class holds the dir entry data and maintains dirty flags for both
// the entry and the data.

// Transacted mode for streams: On the first write, a temp stream pTmpStrm
// is created and operated on. A commit moves pTmpStrm to pCurStrm, which
// is used for subsequent reads. A new write creates a new copy of pTmpStrm
// based on pCurStrm. Reverting throws away pTmpStrm.
// Transacted mode for storages: A copy of the dir ents is kept in aSave.
// Committing means copying aEntry to aSave. Reverting means to copy aSave
// to aEntry, delete newly created entries and to reactivate removed entries.

// Problem der Implementation: Keine Hierarchischen commits. Daher nur
// insgesamt transaktionsorientert oder direkt.

StgDirEntry::StgDirEntry( const void* pBuffer, sal_uInt32 nBufferLen, sal_Bool * pbOk ) : StgAvlNode()
{
	*pbOk = aEntry.Load( pBuffer, nBufferLen );

	InitMembers();
}

StgDirEntry::StgDirEntry( const StgEntry& r ) : StgAvlNode(), aEntry( r )
{
	InitMembers();
}

// Helper for all ctors

void StgDirEntry::InitMembers()
{
	aSave 		= aEntry;
    pUp 		=
	pDown  		= NULL;
    ppRoot 		= NULL;
	pStgStrm 	= NULL;
	pCurStrm	=
	pTmpStrm	= NULL;
	nPos		=
	nEntry 		=
	nRefCnt 	= 0;
	nMode  		= STREAM_READ;
	bDirect 	= sal_True;
	bInvalid	=
	bCreated	=
	bRenamed 	=
	bRemoved	=
	bTemp  		=
	bDirty 		=
	bZombie     = sal_False;
}

StgDirEntry::~StgDirEntry()
{
	Close();
	delete pCurStrm;
	delete pStgStrm;
	delete pDown;
}

// Comparison function

short StgDirEntry::Compare( const StgAvlNode* p ) const
{
    short nResult = -1;
    if ( p )
    {
        const StgDirEntry* pEntry = (const StgDirEntry*) p;
        nResult = aEntry.Compare( pEntry->aEntry );
    }
    return nResult;
}

// Enumerate the entry numbers.
// n is incremented to show the total # of entries.
// These number are later used as page numbers when storing
// the TOC tree into the TOC stream. Remember that aSave is
// stored, not aEntry.

void StgDirEntry::Enum( sal_Int32& n )
{
    sal_Int32 nLeft = STG_FREE, nRight = STG_FREE, nDown = STG_FREE;
    nEntry = n++;
    if( pLeft )
    {
        ((StgDirEntry*) pLeft)->Enum( n ); nLeft = ((StgDirEntry*) pLeft)->nEntry;
    }
    if( pRight )
    {
        ((StgDirEntry*) pRight)->Enum( n ); nRight = ((StgDirEntry*) pRight)->nEntry;
    }
    if( pDown )
    {
        pDown->Enum( n ); nDown = pDown->nEntry;
    }
    aSave.SetLeaf( STG_LEFT, nLeft );
    aSave.SetLeaf( STG_RIGHT, nRight );
    aSave.SetLeaf( STG_CHILD, nDown );
}

// Delete all temporary entries before writing the TOC stream.
// Until now Deltem is never called with bForce True

void StgDirEntry::DelTemp( sal_Bool bForce )
{
	if( pLeft )
        ((StgDirEntry*) pLeft)->DelTemp( sal_False );
    if( pRight )
        ((StgDirEntry*) pRight)->DelTemp( sal_False );
    if( pDown )
	{
		// If the storage is dead, of course all elements are dead, too
		if( bInvalid && aEntry.GetType() == STG_STORAGE )
			bForce = sal_True;
        pDown->DelTemp( bForce );
	}
	if( ( bForce || bInvalid )
	 && ( aEntry.GetType() != STG_ROOT ) /* && ( nRefCnt <= 1 ) */ )
	{
		Close();
		if( pUp )
		{
			// this deletes the element if refcnt == 0!
			sal_Bool bDel = nRefCnt == 0;
		    StgAvlNode::Remove( (StgAvlNode**) &pUp->pDown, this, bDel );
			if( !bDel )
			{
				pLeft = pRight = pDown = 0;
				bInvalid = bZombie = sal_True;
			}
		}
	}
}

// Save the tree into the given dir stream

sal_Bool StgDirEntry::Store( StgDirStrm& rStrm )
{
	void* pEntry = rStrm.GetEntry( nEntry, sal_True );
    if( !pEntry )
        return sal_False;
	// Do not store the current (maybe not commited) entry
	aSave.Store( pEntry );
    if( pLeft )
        if( !((StgDirEntry*) pLeft)->Store( rStrm ) )
            return sal_False;
    if( pRight )
        if( !((StgDirEntry*) pRight)->Store( rStrm ) )
            return sal_False;
    if( pDown )
        if( !pDown->Store( rStrm ) )
            return sal_False;
    return sal_True;
}

sal_Bool StgDirEntry::StoreStream( StgIo& rIo )
{
	if( aEntry.GetType() == STG_STREAM || aEntry.GetType() == STG_ROOT )
	{
		if( bInvalid )
		{
			// Delete the stream if needed
			if( !pStgStrm )
			{
				OpenStream( rIo );
				delete pStgStrm, pStgStrm = NULL;
			}
			else
				pStgStrm->SetSize( 0 );
		}
		// or write the data stream
		else if( !Tmp2Strm() )
			return sal_False;
	}
	return sal_True;
}

// Save all dirty streams

sal_Bool StgDirEntry::StoreStreams( StgIo& rIo )
{
	if( !StoreStream( rIo ) )
		return sal_False;
	if( pLeft )
        if( !((StgDirEntry*) pLeft)->StoreStreams( rIo ) )
            return sal_False;
    if( pRight )
        if( !((StgDirEntry*) pRight)->StoreStreams( rIo ) )
            return sal_False;
    if( pDown )
        if( !pDown->StoreStreams( rIo ) )
            return sal_False;
    return sal_True;
}

// Revert all directory entries after failure to write the TOC stream

void StgDirEntry::RevertAll()
{
	aEntry = aSave;
	if( pLeft )
        ((StgDirEntry*) pLeft)->RevertAll();
    if( pRight )
        ((StgDirEntry*) pRight)->RevertAll();
    if( pDown )
        pDown->RevertAll();
}

// Look if any element of the tree is dirty

sal_Bool StgDirEntry::IsDirty()
{
    if( bDirty || bInvalid )
        return sal_True;
    if( pLeft && ((StgDirEntry*) pLeft)->IsDirty() )
        return sal_True;
    if( pRight && ((StgDirEntry*) pRight)->IsDirty() )
        return sal_True;
    if( pDown && pDown->IsDirty() )
        return sal_True;
    return sal_False;
}

// Set up a stream.

void StgDirEntry::OpenStream( StgIo& rIo, sal_Bool bForceBig )
{
	sal_Int32 nThreshold = (sal_uInt16) rIo.aHdr.GetThreshold();
	delete pStgStrm;
	if( !bForceBig && aEntry.GetSize() < nThreshold )
		pStgStrm = new StgSmallStrm( rIo, *this );
	else
		pStgStrm = new StgDataStrm( rIo, *this );
	if( bInvalid && aEntry.GetSize() )
	{
		// This entry has invalid data, so delete that data
		SetSize( 0L );
//		bRemoved = bInvalid = sal_False;
	}
	nPos = 0;
}

// Close the open stream without committing. If the entry is marked as
// temporary, delete it.
// Do not delete pCurStrm here!
// (TLX:??? Zumindest pStgStrm muss deleted werden.)

void StgDirEntry::Close()
{
	delete pTmpStrm;
	pTmpStrm = NULL;
//	nRefCnt	 = 0;
	bInvalid = bTemp;
}

// Get the current stream size

sal_Int32 StgDirEntry::GetSize()
{
	sal_Int32 n;
	if( pTmpStrm )
		n = pTmpStrm->GetSize();
	else if( pCurStrm )
		n = pCurStrm->GetSize();
	else n = aEntry.GetSize();
	return n;
}

// Set the stream size. This means also creating a temp stream.

sal_Bool StgDirEntry::SetSize( sal_Int32 nNewSize )
{
	if (
	     !( nMode & STREAM_WRITE ) ||
	     (!bDirect && !pTmpStrm && !Strm2Tmp())
	   )
	{
		return sal_False;
	}

	if( nNewSize < nPos )
		nPos = nNewSize;
	if( pTmpStrm )
	{
		pTmpStrm->SetSize( nNewSize );
		pStgStrm->GetIo().SetError( pTmpStrm->GetError() );
		return sal_Bool( pTmpStrm->GetError() == SVSTREAM_OK );
	}
	else
	{
        OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
        if ( !pStgStrm )
            return sal_False;

		sal_Bool bRes = sal_False;
		StgIo& rIo = pStgStrm->GetIo();
		sal_Int32 nThreshold = rIo.aHdr.GetThreshold();
		// ensure the correct storage stream!
		StgStrm* pOld = NULL;
		sal_uInt16 nOldSize = 0;
		if( nNewSize >= nThreshold && pStgStrm->IsSmallStrm() )
		{
			pOld = pStgStrm;
			nOldSize = (sal_uInt16) pOld->GetSize();
			pStgStrm = new StgDataStrm( rIo, STG_EOF, 0 );
		}
		else if( nNewSize < nThreshold && !pStgStrm->IsSmallStrm() )
		{
			pOld = pStgStrm;
			nOldSize = (sal_uInt16) nNewSize;
			pStgStrm = new StgSmallStrm( rIo, STG_EOF, 0 );
		}
		// now set the new size
		if( pStgStrm->SetSize( nNewSize ) )
		{
			// did we create a new stream?
			if( pOld )
			{
				// if so, we probably need to copy the old data
				if( nOldSize )
				{
					void* pBuf = new sal_uInt8[ nOldSize ];
					pOld->Pos2Page( 0L );
					pStgStrm->Pos2Page( 0L );
					if( pOld->Read( pBuf, nOldSize )
					 && pStgStrm->Write( pBuf, nOldSize ) )
						bRes = sal_True;
					delete[] static_cast<sal_uInt8*>(pBuf);
				}
				else
					bRes = sal_True;
				if( bRes )
				{
					pOld->SetSize( 0 );
					delete pOld;
					pStgStrm->Pos2Page( nPos );
					pStgStrm->SetEntry( *this );
				}
				else
				{
					pStgStrm->SetSize( 0 );
					delete pStgStrm;
					pStgStrm = pOld;
				}
			}
			else
			{
				pStgStrm->Pos2Page( nPos );
				bRes = sal_True;
			}
		}
		return bRes;
	}
}

// Seek. On negative values, seek to EOF.

sal_Int32 StgDirEntry::Seek( sal_Int32 nNew )
{
	if( pTmpStrm )
	{
		if( nNew < 0 )
			nNew = pTmpStrm->GetSize();
		nNew = pTmpStrm->Seek( nNew );
	}
	else if( pCurStrm )
	{
		if( nNew < 0 )
			nNew = pCurStrm->GetSize();
		nNew = pCurStrm->Seek( nNew );
	}
	else
	{
        OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
        if ( !pStgStrm )
            return nPos;

		sal_Int32 nSize = aEntry.GetSize();

		if( nNew < 0 )
			nNew = nSize;

		// try to enlarge, the readonly streams should not allow this
		if( nNew > nSize )
		{
			if ( !( nMode & STREAM_WRITE ) || !SetSize( nNew ) )
			{
				OSL_ENSURE( nMode & STREAM_WRITE, "Trying to resize readonly stream by seeking, could be a wrong offset!" );
				return nPos;
			}
			else
				return Seek( nNew );
		}
		pStgStrm->Pos2Page( nNew );
		nNew = pStgStrm->GetPos();
	}

	return nPos = nNew;
}

// Read

sal_Int32 StgDirEntry::Read( void* p, sal_Int32 nLen )
{
	if( nLen <= 0 )
		return 0;
	if( pTmpStrm )
		nLen = pTmpStrm->Read( p, nLen );
	else if( pCurStrm )
		nLen = pCurStrm->Read( p, nLen );
	else
    {
        OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
        if ( !pStgStrm )
            return 0;

		nLen = pStgStrm->Read( p, nLen );
    }

	nPos += nLen;
	return nLen;
}

// Write

sal_Int32 StgDirEntry::Write( const void* p, sal_Int32 nLen )
{
	if( nLen <= 0 || !( nMode & STREAM_WRITE ) )
		return 0;

	// Was this stream committed internally and reopened in direct mode?
	if( bDirect && ( pCurStrm || pTmpStrm ) && !Tmp2Strm() )
		return 0;
	// Is this stream opened in transacted mode? Do we have to make a copy?
	if( !bDirect && !pTmpStrm && !Strm2Tmp() )
		return 0;

    OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
    if ( !pStgStrm )
        return 0;

	if( pTmpStrm )
	{
		nLen = pTmpStrm->Write( p, nLen );
		pStgStrm->GetIo().SetError( pTmpStrm->GetError() );
	}
	else
	{
		sal_Int32 nNew = nPos + nLen;
		if( nNew > pStgStrm->GetSize() )
		{
			if( !SetSize( nNew ) )
				return 0L;
			pStgStrm->Pos2Page( nPos );
		}
		nLen = pStgStrm->Write( p, nLen );
	}
	nPos += nLen;
	return nLen;
}

// Copy the data of one entry into another entry.

void StgDirEntry::Copy( StgDirEntry& rDest )
{
	sal_Int32 n = GetSize();
	if( rDest.SetSize( n ) && n )
	{
		sal_uInt8 aTempBytes[ 4096 ];
		void* p = static_cast<void*>( aTempBytes );
		Seek( 0L );
		rDest.Seek( 0L );
		while( n )
		{
			sal_Int32 nn = n;
			if( nn > 4096 )
				nn = 4096;
			if( Read( p, nn ) != nn )
				break;
			if( rDest.Write( p, nn ) != nn )
				break;
			n -= nn;
		}
	}
}

void StgDirEntry::Copy( BaseStorageStream& rDest )
{
	sal_Int32 n = GetSize();
	if( rDest.SetSize( n ) && n )
	{
        sal_uLong Pos = rDest.Tell();
		sal_uInt8 aTempBytes[ 4096 ];
		void* p = static_cast<void*>( aTempBytes );
		Seek( 0L );
		rDest.Seek( 0L );
		while( n )
		{
			sal_Int32 nn = n;
			if( nn > 4096 )
				nn = 4096;
			if( Read( p, nn ) != nn )
				break;
			if( sal::static_int_cast<sal_Int32>(rDest.Write( p, nn )) != nn )
				break;
			n -= nn;
		}
        rDest.Seek( Pos );             // ?! Seems to be undocumented !
	}
}

// Commit this entry

sal_Bool StgDirEntry::Commit()
{
	// OSL_ENSURE( nMode & STREAM_WRITE, "Trying to commit readonly stream!" );

	aSave = aEntry;
	sal_Bool bRes = sal_True;
	if( aEntry.GetType() == STG_STREAM )
	{
		if( pTmpStrm )
			delete pCurStrm, pCurStrm = pTmpStrm, pTmpStrm = NULL;
		if( bRemoved )
			// Delete the stream if needed
			if( pStgStrm )
				pStgStrm->SetSize( 0 );
	}
	else if( aEntry.GetType() == STG_STORAGE && bDirect && bRes )
	{
		StgIterator aIter( *this );
		for( StgDirEntry* p = aIter.First(); p && bRes; p = aIter.Next() )
			bRes = p->Commit();
	}
	return bRes;
}

// Revert the entry

sal_Bool StgDirEntry::Revert()
{
	aEntry = aSave;
    switch( aEntry.GetType() )
	{
		case STG_STREAM:
			if( pCurStrm )
				delete pTmpStrm, pTmpStrm = pCurStrm, pCurStrm = NULL;
			break;
		case STG_STORAGE:
		{
			sal_Bool bSomeRenamed = sal_False;
			StgIterator aOIter( *this );
		    StgDirEntry* op = aOIter.First();
			while( op )
		    {
				op->aEntry = op->aSave;
				op->bDirty = sal_False;
				bSomeRenamed = sal_Bool( bSomeRenamed | op->bRenamed );
				// Remove any new entries
				if( op->bCreated )
				{
					op->bCreated = sal_False;
					op->Close();
					op->bInvalid = sal_True;
				}
				// Reactivate any removed entries
				else if( op->bRemoved )
					op->bRemoved = op->bInvalid = op->bTemp = sal_False;
				op = aOIter.Next();
			}
			// Resort all renamed entries
			if( bSomeRenamed )
			{
				StgIterator aIter( *this );
			    StgDirEntry* p = aIter.First();
				while( p )
			    {
					if( p->bRenamed )
					{
						StgAvlNode::Move
							( (StgAvlNode**) &p->pUp->pDown,
							  (StgAvlNode**) &p->pUp->pDown, p );
						p->bRenamed = sal_False;
					}
					p = aIter.Next();
				}
			}
			DelTemp( sal_False );
			break;
		}
        case STG_EMPTY:
        case STG_LOCKBYTES:
        case STG_PROPERTY:
        case STG_ROOT:
         break;
	}
    return sal_True;
}

// Copy the stg stream to the temp stream

sal_Bool StgDirEntry::Strm2Tmp()
{
	if( !pTmpStrm )
	{
		sal_uLong n = 0;
		if( pCurStrm )
		{
			// It was already commited once
			pTmpStrm = new StgTmpStrm;
			if( pTmpStrm->GetError() == SVSTREAM_OK && pTmpStrm->Copy( *pCurStrm ) )
				return sal_True;
			n = 1;	// indicates error
		}
		else
		{
			n = aEntry.GetSize();
			pTmpStrm = new StgTmpStrm( n );
			if( pTmpStrm->GetError() == SVSTREAM_OK )
			{
				if( n )
				{
                    OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
                    if ( !pStgStrm )
                        return sal_False;

					sal_uInt8 aTempBytes[ 4096 ];
					void* p = static_cast<void*>( aTempBytes );
					pStgStrm->Pos2Page( 0L );
					while( n )
					{
						sal_uLong nn = n;
						if( nn > 4096 )
							nn = 4096;
						if( (sal_uLong) pStgStrm->Read( p, nn ) != nn )
							break;
						if( pTmpStrm->Write( p, nn ) != nn )
							break;
						n -= nn;
					}
					pStgStrm->Pos2Page( nPos );
					pTmpStrm->Seek( nPos );
				}
			}
			else
				n = 1;
		}

		if( n )
		{
            OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
            if ( pStgStrm )
                pStgStrm->GetIo().SetError( pTmpStrm->GetError() );

			delete pTmpStrm;
			pTmpStrm = NULL;
			return sal_False;
		}
	}
	return sal_True;
}

// Copy the temp stream to the stg stream during the final commit

sal_Bool StgDirEntry::Tmp2Strm()
{
	// We did commit once, but have not written since then
	if( !pTmpStrm )
		pTmpStrm = pCurStrm, pCurStrm = NULL;
	if( pTmpStrm )
	{
        OSL_ENSURE( pStgStrm, "The pointer may not be NULL!" );
        if ( !pStgStrm )
            return sal_False;
		sal_uLong n = pTmpStrm->GetSize();
		StgStrm* pNewStrm;
		StgIo& rIo = pStgStrm->GetIo();
		sal_uLong nThreshold = (sal_uLong) rIo.aHdr.GetThreshold();
		if( n < nThreshold )
			pNewStrm = new StgSmallStrm( rIo, STG_EOF, 0 );
		else
			pNewStrm = new StgDataStrm( rIo, STG_EOF, 0 );
		if( pNewStrm->SetSize( n ) )
		{
			sal_uInt8 p[ 4096 ];
			pTmpStrm->Seek( 0L );
			while( n )
			{
				sal_uLong nn = n;
				if( nn > 4096 )
					nn = 4096;
				if( pTmpStrm->Read( p, nn ) != nn )
					break;
				if( (sal_uLong) pNewStrm->Write( p, nn ) != nn )
					break;
				n -= nn;
			}
			if( n )
			{
				pTmpStrm->Seek( nPos );
				pStgStrm->GetIo().SetError( pTmpStrm->GetError() );
				delete pNewStrm;
				return sal_False;
			}
			else
			{
				pStgStrm->SetSize( 0L );
				delete pStgStrm;
				pStgStrm = pNewStrm;
				pNewStrm->SetEntry( *this );
				pNewStrm->Pos2Page( nPos );
				delete pTmpStrm;
				delete pCurStrm;
				pTmpStrm = pCurStrm = NULL;
				aSave = aEntry;
			}
		}
	}
	return sal_True;
}

// Check if the given entry is contained in this entry

sal_Bool StgDirEntry::IsContained( StgDirEntry* pStg )
{
    if( aEntry.GetType() == STG_STORAGE )
    {
        StgIterator aIter( *this );
        StgDirEntry* p = aIter.First();
        while( p )
        {
            if( !p->aEntry.Compare( pStg->aEntry ) )
                return sal_False;
            if( p->aEntry.GetType() == STG_STORAGE )
                if( !p->IsContained( pStg ) )
                    return sal_False;
            p = aIter.Next();
        }
    }
    return sal_True;
}

// Invalidate all open entries by setting the RefCount to 0. If the bDel
// flag is set, also set the invalid flag to indicate deletion during the
// next dir stream flush.

void StgDirEntry::Invalidate( sal_Bool bDel )
{
//	nRefCnt = 0;
	if( bDel )
		bRemoved = bInvalid = sal_True;
	switch( aEntry.GetType() )
	{
		case STG_STORAGE:
		case STG_ROOT:
		{
			StgIterator aIter( *this );
			for( StgDirEntry* p = aIter.First(); p; p = aIter.Next() )
				p->Invalidate( bDel );
			break;
		}
        default:
            break;
	}
}

///////////////////////////// class StgDirStrm ////////////////////////////

// This specialized stream is the maintenance stream for the directory tree.

StgDirStrm::StgDirStrm( StgIo& r )
          : StgDataStrm( r, r.aHdr.GetTOCStart(), -1 )
		  , pRoot( NULL )
		  , nEntries( 0 )
{
	if( r.GetError() )
		return;
    nEntries = nPageSize / STGENTRY_SIZE;
    if( nStart == STG_EOF )
    {
        StgEntry aRoot;
        aRoot.Init();
        aRoot.SetName( String::CreateFromAscii( RTL_CONSTASCII_STRINGPARAM( "Root Entry" ) ) );
        aRoot.SetType( STG_ROOT );
        pRoot = new StgDirEntry( aRoot );
        pRoot->SetDirty();
    }
    else
    {
        // temporarily use this instance as owner, so
        // the TOC pages can be removed.
        pEntry = (StgDirEntry*) this; // just for a bit pattern
        SetupEntry(0, pRoot, nSize/STGENTRY_SIZE, 0);
        rIo.Revert( pEntry );
        pEntry = NULL;
    }
}

StgDirStrm::~StgDirStrm()
{
    delete pRoot;
}

// Recursively parse the directory tree during reading the TOC stream

void StgDirStrm::SetupEntry (
    const sal_Int32 n,
    StgDirEntry* pUpper,
    const sal_Int32 nEntryCount,
    const sal_Int32 nDepth)
{
    if (nDepth > nEntryCount)
    {
        // Tree grew higher than there are different nodes.  Looks like
        // something is wrong with the file.  Return now to avoid
        // infinite recursion.
        return;
    }
    else if (n>=nEntryCount || (n<0 && n!=STG_FREE))
    {
        // n has an invalid value.  Don't access the corresponding
        // stream content.
        return;
    }

    void* p = ( n == STG_FREE ) ? NULL : GetEntry( n );
    if( p )
    {
        sal_Bool bOk(sal_False);
        StgDirEntry* pCur = new StgDirEntry( p, STGENTRY_SIZE, &bOk );

        if( !bOk )
        {
            delete pCur;
            rIo.SetError( SVSTREAM_GENERALERROR );
            // an error occurred
            return;
        }

        // better it is
        if( !pUpper )
            pCur->aEntry.SetType( STG_ROOT );

        sal_Int32 nLeft = pCur->aEntry.GetLeaf( STG_LEFT );
        sal_Int32 nRight = pCur->aEntry.GetLeaf( STG_RIGHT );
        // substorage?
        sal_Int32 nLeaf = STG_FREE;
        if( pCur->aEntry.GetType() == STG_STORAGE || pCur->aEntry.GetType() == STG_ROOT )
        {
            nLeaf = pCur->aEntry.GetLeaf( STG_CHILD );
            if (nLeaf != STG_FREE && nLeaf == n)
            {
                delete pCur;
                rIo.SetError( SVSTREAM_GENERALERROR );
                return;
            }
        }

        if( nLeaf != 0 && nLeft != 0 && nRight != 0 )
        {
            if( StgAvlNode::Insert
                ( (StgAvlNode**) ( pUpper ? &pUpper->pDown : &pRoot ), pCur ) )
            {
                pCur->pUp    = pUpper;
                pCur->ppRoot = &pRoot;
            }
            else
            {
                rIo.SetError( SVSTREAM_CANNOT_MAKE );
                delete pCur; pCur = NULL;
                return;
            }
            SetupEntry( nLeft, pUpper, nEntryCount, nDepth+1);
            SetupEntry( nRight, pUpper, nEntryCount, nDepth+1);
            SetupEntry( nLeaf, pCur, nEntryCount, nDepth+1);
        }
        else
            delete pCur;
    }
}

// Extend or shrink the directory stream.

sal_Bool StgDirStrm::SetSize( sal_Int32 nBytes )
{
    // Always allocate full pages
    if ( nBytes < 0 )
        nBytes = 0;

    nBytes = ( ( nBytes + nPageSize - 1 ) / nPageSize ) * nPageSize;
    return StgStrm::SetSize( nBytes );
}

// Save the TOC stream into a new substream after saving all data streams

sal_Bool StgDirStrm::Store()
{
    if( !pRoot || !pRoot->IsDirty() )
        return sal_True;
	if( !pRoot->StoreStreams( rIo ) )
		return sal_False;
	// After writing all streams, the data FAT stream has changed,
	// so we have to commit the root again
	pRoot->Commit();
	// We want a completely new stream, so fake an empty stream
    sal_Int32 nOldStart = nStart;       // save for later deletion
    sal_Int32 nOldSize  = nSize;
    nStart = nPage = STG_EOF;
    nSize  = nPos = 0;
    nOffset = 0;
	// Delete all temporary entries
	pRoot->DelTemp( sal_False );
    // set the entry numbers
    sal_Int32 n = 0;
    pRoot->Enum( n );
    if( !SetSize( n * STGENTRY_SIZE ) )
    {
        nStart = nOldStart; nSize = nOldSize;
		pRoot->RevertAll();
        return sal_False;
    }
    // set up the cache elements for the new stream
    if( !Copy( STG_FREE, nSize ) )
	{
		pRoot->RevertAll();
        return sal_False;
	}
    // Write the data to the new stream
    if( !pRoot->Store( *this ) )
	{
		pRoot->RevertAll();
        return sal_False;
	}
	// fill any remaining entries with empty data
    sal_Int32 ne = nSize / STGENTRY_SIZE;
	StgEntry aEmpty;
	aEmpty.Init();
    while( n < ne )
    {
        void* p = GetEntry( n++, sal_True );
        if( !p )
		{
			pRoot->RevertAll();
            return sal_False;
		}
		aEmpty.Store( p );
    }
    // Now we can release the old stream
    pFat->FreePages( nOldStart, sal_True );
    rIo.aHdr.SetTOCStart( nStart );
	return sal_True;
}

// Get a dir entry.

void* StgDirStrm::GetEntry( sal_Int32 n, sal_Bool bDirty )
{
    if( n < 0 )
        return NULL;

    n *= STGENTRY_SIZE;
    if( n < 0 && n >= nSize )
        return NULL;
    return GetPtr( n, sal_True, bDirty );
}

// Find a dir entry.

StgDirEntry* StgDirStrm::Find( StgDirEntry& rStg, const String& rName )
{
    if( rStg.pDown )
    {
        StgEntry aEntry;
        aEntry.Init();
        if( !aEntry.SetName( rName ) )
        {
            rIo.SetError( SVSTREAM_GENERALERROR );
            return NULL;
        }
        // Look in the directory attached to the entry
        StgDirEntry aTest( aEntry );
        return (StgDirEntry*) rStg.pDown->Find( &aTest );
    }
    else
        return NULL;
}

// Create a new entry.

StgDirEntry* StgDirStrm::Create
	( StgDirEntry& rStg, const String& rName, StgEntryType eType )
{
	StgEntry aEntry;
    aEntry.Init();
	aEntry.SetType( eType );
    if( !aEntry.SetName( rName ) )
    {
        rIo.SetError( SVSTREAM_GENERALERROR );
        return NULL;
    }
    StgDirEntry* pRes = Find( rStg, rName );
	if( pRes )
	{
		if( !pRes->bInvalid )
		{
			rIo.SetError( SVSTREAM_CANNOT_MAKE );
			return NULL;
		}
		pRes->bInvalid =
		pRes->bRemoved =
		pRes->bTemp    = sal_False;
		pRes->bCreated =
        pRes->bDirty   = sal_True;
	}
	else
	{
		pRes = new StgDirEntry( aEntry );
	    if( StgAvlNode::Insert( (StgAvlNode**) &rStg.pDown, pRes ) )
	    {
			pRes->pUp    = &rStg;
	        pRes->ppRoot = &pRoot;
			pRes->bCreated =
	        pRes->bDirty = sal_True;
	    }
	    else
	    {
	        rIo.SetError( SVSTREAM_CANNOT_MAKE );
	        delete pRes; pRes = NULL;
	    }
	}
	return pRes;
}

// Rename the given entry.

sal_Bool StgDirStrm::Rename( StgDirEntry& rStg, const String& rOld, const String& rNew )
{
    StgDirEntry* p = Find( rStg, rOld );
    if( p )
    {

		if( !StgAvlNode::Remove( (StgAvlNode**) &rStg.pDown, p, sal_False ) )
			return sal_False;
		p->aEntry.SetName( rNew );
		if( !StgAvlNode::Insert( (StgAvlNode**) &rStg.pDown, p ) )
			return sal_False;
		p->bRenamed = p->bDirty   = sal_True;
		return sal_True;
    }
    else
    {
        rIo.SetError( SVSTREAM_FILE_NOT_FOUND );
        return sal_False;
    }
}

// Move the given entry to a different storage.

sal_Bool StgDirStrm::Move( StgDirEntry& rStg1, StgDirEntry& rStg2, const String& rName )
{
    StgDirEntry* p = Find( rStg1, rName );
    if( p )
	{
		if( !StgAvlNode::Move
			( (StgAvlNode**) &rStg1.pDown, (StgAvlNode**) &rStg2.pDown, p ) )
			return sal_False;
		p->bDirty = sal_True;
		return sal_True;
	}
	else
    {
        rIo.SetError( SVSTREAM_FILE_NOT_FOUND );
        return sal_False;
    }
}