libreoffice/svl/source/misc/documentlockfile.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 <com/sun/star/ucb/XCommandEnvironment.hpp>
#include <com/sun/star/ucb/InsertCommandArgument.hpp>
#include <com/sun/star/ucb/NameClashException.hpp>
#include <com/sun/star/io/WrongFormatException.hpp>
#include <com/sun/star/io/TempFile.hpp>
#include <com/sun/star/io/XStream.hpp>
#include <com/sun/star/io/XInputStream.hpp>
#include <com/sun/star/io/XOutputStream.hpp>
#include <com/sun/star/io/XSeekable.hpp>
#include <com/sun/star/io/XTruncate.hpp>

#include <o3tl/enumrange.hxx>

#include <rtl/string.hxx>
#include <rtl/ustring.hxx>
#include <rtl/ustrbuf.hxx>

#include <comphelper/processfactory.hxx>

#include <ucbhelper/content.hxx>

#include <svl/documentlockfile.hxx>

using namespace ::com::sun::star;

namespace svt {

GenDocumentLockFile::GenDocumentLockFile(const OUString& aLockFileURL)
    : LockFileCommon(aLockFileURL)
{
}


GenDocumentLockFile::~GenDocumentLockFile()
{
}

uno::Reference< io::XInputStream > GenDocumentLockFile::OpenStream(std::unique_lock<std::mutex>& /*rGuard*/)
{
    uno::Reference < css::ucb::XCommandEnvironment > xEnv;
    ::ucbhelper::Content aSourceContent( GetURL(), xEnv, comphelper::getProcessComponentContext() );

    // the file can be opened readonly, no locking will be done
    return aSourceContent.openStream();
}

bool GenDocumentLockFile::CreateOwnLockFile()
{
    std::unique_lock aGuard( m_aMutex );

    try
    {
        uno::Reference< io::XStream > xTempFile(
            io::TempFile::create( comphelper::getProcessComponentContext() ),
            uno::UNO_QUERY_THROW );
        uno::Reference< io::XSeekable > xSeekable( xTempFile, uno::UNO_QUERY_THROW );

        uno::Reference< io::XInputStream > xInput = xTempFile->getInputStream();
        uno::Reference< io::XOutputStream > xOutput = xTempFile->getOutputStream();

        if ( !xInput.is() || !xOutput.is() )
            throw uno::RuntimeException();

        LockFileEntry aNewEntry = GenerateOwnEntry();
        WriteEntryToStream( aGuard, aNewEntry, xOutput );
        xOutput->closeOutput();

        xSeekable->seek( 0 );

        uno::Reference < css::ucb::XCommandEnvironment > xEnv;
        ::ucbhelper::Content aTargetContent( GetURL(), xEnv, comphelper::getProcessComponentContext() );

        ucb::InsertCommandArgument aInsertArg;
        aInsertArg.Data = std::move(xInput);
        aInsertArg.ReplaceExisting = false;
        uno::Any aCmdArg;
        aCmdArg <<= aInsertArg;
        aTargetContent.executeCommand( u"insert"_ustr, aCmdArg );

        // try to let the file be hidden if possible
        try {
            aTargetContent.setPropertyValue(u"IsHidden"_ustr, uno::Any( true ) );
        } catch( uno::Exception& ) {}
    }
    catch( ucb::NameClashException& )
    {
        return false;
    }

    return true;
}

bool GenDocumentLockFile::OverwriteOwnLockFile()
{
    std::unique_lock aGuard(m_aMutex);

    // allows to overwrite the lock file with the current data
    try
    {
        uno::Reference < css::ucb::XCommandEnvironment > xEnv;
        ::ucbhelper::Content aTargetContent( GetURL(), xEnv, comphelper::getProcessComponentContext() );

        LockFileEntry aNewEntry = GenerateOwnEntry();

        uno::Reference< io::XStream > xStream = aTargetContent.openWriteableStreamNoLock();
        uno::Reference< io::XOutputStream > xOutput = xStream->getOutputStream();
        uno::Reference< io::XTruncate > xTruncate( xOutput, uno::UNO_QUERY_THROW );

        xTruncate->truncate();
        WriteEntryToStream( aGuard, aNewEntry, xOutput );
        xOutput->closeOutput();
    }
    catch( uno::Exception& )
    {
        return false;
    }

    return true;
}

void GenDocumentLockFile::RemoveFile()
{
    std::unique_lock aGuard( m_aMutex );

    // TODO/LATER: the removing is not atomic, is it possible in general to make it atomic?
    LockFileEntry aNewEntry = GenerateOwnEntry();
    LockFileEntry aFileData = GetLockDataImpl(aGuard);

    if ( aFileData[LockFileComponent::SYSUSERNAME] != aNewEntry[LockFileComponent::SYSUSERNAME]
      || aFileData[LockFileComponent::LOCALHOST] != aNewEntry[LockFileComponent::LOCALHOST]
      || aFileData[LockFileComponent::USERURL] != aNewEntry[LockFileComponent::USERURL] )
        throw io::IOException(); // not the owner, access denied

    RemoveFileDirectly();
}

void GenDocumentLockFile::RemoveFileDirectly()
{
    uno::Reference < css::ucb::XCommandEnvironment > xEnv;
    ::ucbhelper::Content aCnt(GetURL(), xEnv, comphelper::getProcessComponentContext());
    aCnt.executeCommand(u"delete"_ustr,
        uno::Any(true));
}

LockFileEntry GenDocumentLockFile::GetLockData()
{
    std::unique_lock aGuard(m_aMutex);
    return GetLockDataImpl(aGuard);
}

DocumentLockFile::DocumentLockFile( std::u16string_view aOrigURL )
    : GenDocumentLockFile(GenerateOwnLockFileURL(aOrigURL, u".~lock."))
{
}


DocumentLockFile::~DocumentLockFile()
{
}


void DocumentLockFile::WriteEntryToStream(
    std::unique_lock<std::mutex>& /*rGuard*/,
    const LockFileEntry& aEntry, const uno::Reference< io::XOutputStream >& xOutput )
{
    OUStringBuffer aBuffer(256);

    for ( LockFileComponent lft : o3tl::enumrange<LockFileComponent>() )
    {
        aBuffer.append( EscapeCharacters( aEntry[lft] ) );
        if ( lft < LockFileComponent::LAST )
            aBuffer.append( ',' );
        else
            aBuffer.append( ';' );
    }

    OString aStringData( OUStringToOString( aBuffer, RTL_TEXTENCODING_UTF8 ) );
    uno::Sequence< sal_Int8 > aData( reinterpret_cast<sal_Int8 const *>(aStringData.getStr()), aStringData.getLength() );
    xOutput->writeBytes( aData );
}

LockFileEntry DocumentLockFile::GetLockDataImpl(std::unique_lock<std::mutex>& rGuard)
{
    uno::Reference< io::XInputStream > xInput = OpenStream(rGuard);
    if ( !xInput.is() )
        throw uno::RuntimeException();

    const sal_Int32 nBufLen = 32000;
    uno::Sequence< sal_Int8 > aBuffer( nBufLen );

    sal_Int32 nRead = xInput->readBytes( aBuffer, nBufLen );
    xInput->closeInput();

    if ( nRead == nBufLen )
        throw io::WrongFormatException();

    sal_Int32 nCurPos = 0;
    return ParseEntry( aBuffer, nCurPos );
}




} // namespace svt

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