path: root/tools/source/ref/pstm.cxx

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   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 .
 */

#include <tools/pstm.hxx>
#include <rtl/strbuf.hxx>
#include <osl/diagnose.h>
#include <sal/log.hxx>

#define STOR_NO_OPTIMIZE

void SvClassManager::Register( sal_Int32 nClassId, SvCreateInstancePersist pFunc )
{
#ifdef DBG_UTIL
    SvCreateInstancePersist p;
    p = Get( nClassId );
    assert( (!p || p == pFunc) && "register class with same id");
#endif
    aAssocTable.insert(Map::value_type(nClassId, pFunc));
}

SvCreateInstancePersist SvClassManager::Get( sal_Int32 nClassId )
{
    Map::const_iterator i(aAssocTable.find(nClassId));
    return i == aAssocTable.end() ? nullptr : i->second;
}

/** Constructor

    @param rMgr       Stores factories for objects that can persisted
    @param pStream    This stream is used as the medium for PersistStream
    @param nStartIdxP Start value for object identifier (set > 0 )

    @warning Objects rMgr and pStream must not be manipulated while used in
             SvPersistStream. An Exception to this is pvStream
             (cf. <SvPersistStream::SetStream>).
    @see SvPersistStream::SetStream
*/
SvPersistStream::SvPersistStream( SvClassManager & rMgr, SvStream * pStream )
    : rClassMgr( rMgr )
    , pStm( pStream )
    , aPUIdx( UniqueIndex<SvPersistBase>::Index(1) )
    , nStartIdx( 1 )
{
    m_isWritable = true;
    if( pStm )
    {
        SetVersion( pStm->GetVersion() );
        SetError( pStm->GetError() );
        SyncSvStream( pStm->Tell() );
    }
}

SvPersistStream::~SvPersistStream()
{
    if( pStm != nullptr )
    {
        SyncSysStream();
        pStm->SetError( GetError() );
        pStm = nullptr;
    }
}

void SvPersistStream::ResetError()
{
    SvStream::ResetError();
    assert(pStm && "stream not set");
    pStm->ResetError();
}

std::size_t SvPersistStream::GetData( void* pData, std::size_t nSize )
{
    assert(pStm && "stream not set");
    std::size_t const nRet = pStm->ReadBytes( pData, nSize );
    SetError( pStm->GetError() );
    return nRet;
}

std::size_t SvPersistStream::PutData( const void* pData, std::size_t nSize )
{
    assert(pStm && "stream not set");
    std::size_t const nRet = pStm->WriteBytes( pData, nSize );
    SetError( pStm->GetError() );
    return nRet;
}

sal_uInt64 SvPersistStream::SeekPos(sal_uInt64 const nPos)
{
    assert(pStm && "stream not set");
    sal_uInt64 nRet = pStm->Seek( nPos );
    SetError( pStm->GetError() );
    return nRet;
}

void SvPersistStream::FlushData()
{
}

SvPersistStream::Index SvPersistStream::GetIndex( SvPersistBase * pObj ) const
{
    PersistBaseMap::const_iterator it = aPTable.find( pObj );
    if( it == aPTable.end() )
    {
        return Index(0);
    }
    return it->second;
}

SvPersistBase * SvPersistStream::GetObject( Index nIdx ) const
{
    if( nIdx >= nStartIdx )
        return aPUIdx.Get( nIdx );
    return nullptr;
}

#define LEN_1           0x80
#define LEN_2           0x40
#define LEN_4           0x20
#define LEN_5           0x10

/** Reads a compressed word from the stream.

    For details on what format is used for compression, see
    <SvPersistStream::WriteCompressed>.

    @param rStm Source to read compressed data from

    @return Uncompressed word
    @see SvPersistStream::WriteCompressed
*/
sal_uInt32 SvPersistStream::ReadCompressed( SvStream & rStm )
{
    sal_uInt32 nRet(0);
    sal_uInt8   nMask;
    rStm.ReadUChar( nMask );
    if( nMask & LEN_1 )
        nRet = ~LEN_1 & nMask;
    else if( nMask & LEN_2 )
    {
        nRet = ~LEN_2 & nMask;
        nRet <<= 8;
        rStm.ReadUChar( nMask );
        nRet |= nMask;
    }
    else if( nMask & LEN_4 )
    {
        nRet = ~LEN_4 & nMask;
        nRet <<= 8;
        rStm.ReadUChar( nMask );
        nRet |= nMask;
        nRet <<= 16;
        sal_uInt16 n;
        rStm.ReadUInt16( n );
        nRet |= n;
    }
    else if( nMask & LEN_5 )
    {
        if( nMask & 0x0F )
        {
            rStm.SetError( SVSTREAM_FILEFORMAT_ERROR );
            OSL_FAIL( "format error" );
        }
        rStm.ReadUInt32( nRet );
    }
    else
    {
        rStm.SetError( SVSTREAM_FILEFORMAT_ERROR );
        OSL_FAIL( "format error" );
    }
    return nRet;
}

/** Writes compressed stream

    @param rStm Source for writing compressed data
    @param nVal This value will be compressed and written

    nVal is compressed and written to stream using the following algorithm
    nVal < 0x80         =>  0x80        + nVal of size 1 Byte.
    nVal < 0x4000       =>  0x4000      + nVal of size 2 Byte.
    nVal < 0x20000000   =>  0x20000000  + nVal of size 4 Byte.
    nVal > 0x1FFFFFFF   =>  0x1000000000+ nVal of size 5 Byte.

    @see SvPersistStream::ReadCompressed
*/
void SvPersistStream::WriteCompressed( SvStream & rStm, sal_uInt32 nVal )
{
#ifdef STOR_NO_OPTIMIZE
    if( nVal < 0x80 )
        rStm.WriteUChar( LEN_1 | nVal );
    else if( nVal < 0x4000 )
    {
        rStm.WriteUChar( LEN_2 | (nVal >> 8) );
        rStm.WriteUChar( nVal );
    }
    else if( nVal < 0x20000000 )
    {
        // highest sal_uInt8
        rStm.WriteUChar( LEN_4 | (nVal >> 24) );
        // 2nd highest sal_uInt8
        rStm.WriteUChar( nVal >> 16 );
        rStm.WriteUInt16( nVal );
    }
    else
#endif
    {
        rStm.WriteUChar( LEN_5 );
        rStm.WriteUInt32( nVal );
    }
}

/** This method writes length value of 4 Bytes to the stream and returns the
    stream position.

    Example:
    @code
    sal_uInt32 nObjPos = rStm.WriteDummyLen();
    ...
    // write data
    ...
    rStm.WriteLen( nObjPos );
    @endcode

    @return Position of stream behind length value

    @see SvPersistStream::ReadLen
    @see SvPersistStream::WriteLen
*/
sal_uInt32 SvPersistStream::WriteDummyLen()
{
    WriteUInt32( 0 );
    return Tell();
}

/** Write difference between current position and nObjPos
    as sal_uInt32 to position nObjPos-4 in the stream.

    Afterwards, reset stream to old position.

    Example: Difference does not contain length value
    @code
    sal_uInt32 nObjPos = rStm.WriteDummyLen();
    ...
    // write data
    ...
    rStm.WriteLen( nObjPos );
    // write more data
    @endcode

    @param nObjPos Position+4, on which length is written to

    @see SvPersistStream::ReadLen
    @see SvPersistStream::WriteDummyLen
*/
void SvPersistStream::WriteLen( sal_uInt32 nObjPos )
{
    sal_uInt32 nPos = Tell();
    sal_uInt32 nLen = nPos - nObjPos;
    // Length in stream must be 4 Bytes
    Seek( nObjPos - sizeof( sal_uInt32 ) );
    // write length
    WriteUInt32( nLen );
    Seek( nPos );
}

/** Read a length value written to stream

    @param pTestPos Position of the stream after reading length. May be NULL.

    @see SvPersistStream::WriteDummyLen
    @see SvPersistStream::WriteLen
*/
sal_uInt32 SvPersistStream::ReadLen( sal_uInt32 * pTestPos )
{
    sal_uInt32 nLen;
    ReadUInt32( nLen );
    if( pTestPos )
        *pTestPos = Tell();
    return nLen;
}

// File format backward-compatible
#ifdef STOR_NO_OPTIMIZE
#define P_VER       (sal_uInt8)0x00
#else
#define P_VER       (sal_uInt8)0x01
#endif
#define P_VER_MASK  (sal_uInt8)0x0F
#define P_ID_0      (sal_uInt8)0x80
#define P_OBJ       (sal_uInt8)0x40
#define P_DBGUTIL   (sal_uInt8)0x20
#define P_ID        (sal_uInt8)0x10
#ifdef STOR_NO_OPTIMIZE
#define P_STD   P_DBGUTIL
#else
#define P_STD   0
#endif

static void WriteId
(
    SvStream & rStm,
    sal_uInt8 nHdr,
    sal_uInt32 nId,
    sal_uInt16 nClassId
)
{
#ifdef STOR_NO_OPTIMIZE
    nHdr |= P_ID;
#endif
    nHdr |= P_VER;
    if( nHdr & P_ID )
    {
        if( (nHdr & P_OBJ) || nId != 0 )
        { // Id set only for pointers or DBGUTIL
            rStm.WriteUChar( nHdr );
            SvPersistStream::WriteCompressed( rStm, nId );
        }
        else
        { // NULL Pointer
            rStm.WriteUChar( nHdr | P_ID_0 );
            return;
        }
    }
    else
        rStm.WriteUChar( nHdr );

    if( (nHdr & P_DBGUTIL) || (nHdr & P_OBJ) )
        // Objects always have a class id
        // Pointers only for DBG_UTIL and != NULL
        SvPersistStream::WriteCompressed( rStm, nClassId );
}

static void ReadId
(
    SvStream & rStm,
    sal_uInt8 & nHdr,
    SvPersistStream::Index & nId,
    sal_uInt16 & nClassId
)
{
    nClassId = 0;
    rStm.ReadUChar( nHdr );
    if( nHdr & P_ID_0 )
        nId = SvPersistStream::Index(0);
    else
    {
        if( (nHdr & P_VER_MASK) == 0 )
        {
            if( (nHdr & P_DBGUTIL) || !(nHdr & P_OBJ) )
                nId = SvPersistStream::Index(SvPersistStream::ReadCompressed( rStm ));
            else
                nId = SvPersistStream::Index(0);
        }
        else if( nHdr & P_ID )
            nId = SvPersistStream::Index(SvPersistStream::ReadCompressed( rStm ));

        if( (nHdr & P_DBGUTIL) || (nHdr & P_OBJ) )
            nClassId = (sal_uInt16)SvPersistStream::ReadCompressed( rStm );
    }
}

void SvPersistStream::WriteObj
(
    sal_uInt8 nHdr,
    SvPersistBase * pObj
)
{
#ifdef STOR_NO_OPTIMIZE
    sal_uInt32 nObjPos = 0;
    if( nHdr & P_DBGUTIL )
        // remember position for length value
        nObjPos = WriteDummyLen();
#endif
    pObj->Save( *this );
#ifdef STOR_NO_OPTIMIZE
    if( nHdr & P_DBGUTIL )
        WriteLen( nObjPos );
#endif
}

SvPersistStream& SvPersistStream::WritePointer
(
    SvPersistBase * pObj
)
{
    sal_uInt8 nP = P_STD;

    if( pObj )
    {
        Index nId = GetIndex( pObj );
        if( nId )
            nP |= P_ID;
        else
        {
            nId = aPUIdx.Insert( pObj );
            aPTable[ pObj ] = nId;
            nP |= P_OBJ;
        }
        WriteId( *this, nP, (sal_uInt32)nId, pObj->GetClassId() );
        if( nP & P_OBJ )
            WriteObj( nP, pObj );
    }
    else
    { // NULL Pointer
        WriteId( *this, nP | P_ID, 0, 0 );
    }
    return *this;
}

void SvPersistStream::ReadObj
(
    SvPersistBase * &   rpObj
)
{
    sal_uInt8   nHdr;
    Index       nId(0);
    sal_uInt16  nClassId;

    rpObj = nullptr; // specification: 0 in case of error
    ReadId( *this, nHdr, nId, nClassId );

    // get version number through masking
    if( P_VER < (nHdr & P_VER_MASK) )
    {
        SetError( SVSTREAM_FILEFORMAT_ERROR );
        OSL_FAIL( "false version" );
    }

    if( !(nHdr & P_ID_0) && GetError() == ERRCODE_NONE )
    {
        if( P_OBJ & nHdr )
        { // read object, nId only set for P_DBGUTIL
            SAL_WARN_IF( (nHdr & P_DBGUTIL) && nullptr != aPUIdx.Get( nId ), "tools","object already exists");
            SvCreateInstancePersist pFunc = rClassMgr.Get( nClassId );

            sal_uInt32 nObjLen(0), nObjPos(0);
            if( nHdr & P_DBGUTIL )
                nObjLen = ReadLen( &nObjPos );
            if( !pFunc )
            {
#ifdef DBG_UTIL
                SAL_INFO( "tools", "no class with id: " << nClassId << " registered" );
#else
                (void)nObjLen;
#endif
                SetError( ERRCODE_IO_NOFACTORY );
                return;
            }
            pFunc( &rpObj );
            // Save reference
            rpObj->AddFirstRef();

            // insert into table
            const Index nNewId = aPUIdx.Insert( rpObj );
            // in order to restore state after saving
            aPTable[ rpObj ] = nNewId;
            SAL_WARN_IF( (nHdr & P_DBGUTIL) && (nId != nNewId), "tools","read write id conflict: not the same");

            rpObj->Load( *this );
            SAL_WARN_IF( nObjLen + nObjPos != Tell(), "tools", "false object len: read = " << (Tell() - nObjPos)
                            << ", should = " << nObjLen);
            rpObj->RestoreNoDelete();
            rpObj->ReleaseRef();
        }
        else
        {
            rpObj = GetObject( nId );
            SAL_WARN_IF(rpObj==nullptr,"tools","object does not exist");
            SAL_WARN_IF( rpObj->GetClassId() != nClassId , "tools" , "class mismatch" );
        }
    }
}

SvPersistStream& SvPersistStream::ReadPointer
(
    SvPersistBase * & rpObj
)
{
    ReadObj( rpObj );
    return *this;
}

SvPersistStream& WriteSvPersistBase
(
    SvPersistStream & rStm,
    SvPersistBase * pObj
)
{
    return rStm.WritePointer( pObj );
}

SvPersistStream& operator >>
(
    SvPersistStream & rStm,
    SvPersistBase * & rpObj
)
{
    return rStm.ReadPointer( rpObj );
}

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