xref: /AOO41X/main/desktop/source/deployment/dp_persmap.cxx (revision 47148b3bc50811ceb41802e4cc50a5db21535900)

/**************************************************************
 *
 * 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_desktop.hxx"

#include "dp_misc.h"
#include "dp_persmap.h"
#include "rtl/strbuf.hxx"

using namespace ::rtl;

// the persistent map is used to manage a handful of key-value string pairs
// this implementation replaces a rather heavy-weight berkeleydb integration

// the file backing up a persistent map consists of line pairs with
// - a key string   (encoded with chars 0x00..0x0F being escaped)
// - a value string (encoded with chars 0x00..0x0F being escaped)

namespace dp_misc
{

static const char PmapMagic[4] = {'P','m','p','1'};

//______________________________________________________________________________
PersistentMap::PersistentMap( OUString const & url_, bool readOnly )
:   m_MapFile( expandUnoRcUrl(url_) )
,   m_bReadOnly( readOnly)
,   m_bIsOpen( false)
,   m_bToBeCreated( !readOnly)
,   m_bIsDirty( false)
{
    open();
}

//______________________________________________________________________________
PersistentMap::PersistentMap()
:   m_MapFile( OUString())
,   m_bReadOnly( false)
,   m_bIsOpen( false)
,   m_bToBeCreated( false)
,   m_bIsDirty( false)
{}

//______________________________________________________________________________
PersistentMap::~PersistentMap()
{
    if( m_bIsDirty)
        flush();
    if( m_bIsOpen)
        m_MapFile.close();
}

//______________________________________________________________________________

// replace 0x00..0x0F with "%0".."%F"
// replace "%" with "%%"
static OString encodeString( const OString& rStr)
{
    const sal_Char* pChar = rStr.getStr();
    const sal_Int32 nLen = rStr.getLength();
    sal_Int32 i = nLen;
    // short circuit for the simple non-encoded case
    while( --i >= 0)
    {
        const sal_Char c = *(pChar++);
        if( (0x00 <= c) && (c <= 0x0F))
            break;
        if( c == '%')
            break;
    }
    if( i < 0)
        return rStr;

    // escape chars 0x00..0x0F with "%0".."%F"
    OStringBuffer aEncStr( nLen + 32);
    aEncStr.append( pChar - (nLen-i), nLen - i);
    while( --i >= 0)
    {
        sal_Char c = *(pChar++);
        if( (0x00 <= c) && (c <= 0x0F))
        {
            aEncStr.append( '%');
            c += (c <= 0x09) ? '0' : 'A'-10;
        } else if( c == '%')
            aEncStr.append( '%');
        aEncStr.append( c);
    }

    return aEncStr.makeStringAndClear();
}

//______________________________________________________________________________

// replace "%0".."%F" with 0x00..0x0F
// replace "%%" with "%"
static OString decodeString( const sal_Char* pEncChars, int nLen)
{
    const char* pChar = pEncChars;
    sal_Int32 i = nLen;
    // short circuit for the simple non-encoded case
    while( --i >= 0)
        if( *(pChar++) == '%')
            break;
    if( i < 0)
        return OString( pEncChars, nLen);

    // replace escaped chars with their decoded counterparts
    OStringBuffer aDecStr( nLen);
    pChar = pEncChars;
    for( i = nLen; --i >= 0;)
    {
        sal_Char c = *(pChar++);
        // handle escaped character
        if( c == '%')
        {
            --i;
            OSL_ASSERT( i >= 0);
            c = *(pChar++);
            if( ('0' <= c) && (c <= '9'))
                c -= '0';
            else
            {
                OSL_ASSERT( ('A' <= c) && (c <= 'F'));
                c -= ('A'-10);
            }
        }
        aDecStr.append( c);
    }

    return aDecStr.makeStringAndClear();
}

//______________________________________________________________________________
bool PersistentMap::open()
{
    // open the existing file
    sal_uInt32 nOpenFlags = osl_File_OpenFlag_Read;
    if( !m_bReadOnly)
        nOpenFlags |= osl_File_OpenFlag_Write;

    const osl::File::RC rcOpen = m_MapFile.open( nOpenFlags);
    m_bIsOpen = (rcOpen == osl::File::E_None);

    // or create later if needed
    m_bToBeCreated &= (rcOpen == osl::File::E_NOENT) && !m_bIsOpen;

    if( !m_bIsOpen)
        return m_bToBeCreated;

    const bool readOK = readAll();
    return readOK;
}

//______________________________________________________________________________
bool PersistentMap::readAll()
{
    // prepare for re-reading the map-file
    m_MapFile.setPos( osl_Pos_Absolut, 0);
    m_entries.clear();

    // read header and check magic
    char aHeaderBytes[ sizeof(PmapMagic)];
    sal_uInt64 nBytesRead = 0;
    m_MapFile.read( aHeaderBytes, sizeof(aHeaderBytes), nBytesRead);
    OSL_ASSERT( nBytesRead == sizeof(aHeaderBytes));
    if( nBytesRead != sizeof(aHeaderBytes))
        return false;
    // check header magic
    for( int i = 0; i < (int)sizeof(PmapMagic); ++i)
        if( aHeaderBytes[i] != PmapMagic[i])
            return false;

    // read key value pairs and add them to the map
    ByteSequence aKeyLine;
    ByteSequence aValLine;
    for(;;)
    {
        // read key-value line pair
        // an empty key name indicates the end of the line pairs
        if( m_MapFile.readLine( aKeyLine) != osl::File::E_None)
            return false;
        if( !aKeyLine.getLength())
            break;
        if( m_MapFile.readLine( aValLine) != osl::File::E_None)
            return false;
        // decode key and value strings
        const OString aKeyName = decodeString( (sal_Char*)aKeyLine.getConstArray(), aKeyLine.getLength());
        const OString aValName = decodeString( (sal_Char*)aValLine.getConstArray(), aValLine.getLength());
        // insert key-value pair into map
        add( aKeyName, aValName);
        // check end-of-file status
        sal_Bool bIsEOF = true;
        if( m_MapFile.isEndOfFile( &bIsEOF) != osl::File::E_None)
            return false;
        if( bIsEOF)
            break;
    }

    m_bIsDirty = false;
    return true;
}

//______________________________________________________________________________
void PersistentMap::flush( void)
{
    if( !m_bIsDirty)
        return;
    OSL_ASSERT( !m_bReadOnly);
    if( m_bToBeCreated && !m_entries.empty())
    {
        const sal_uInt32 nOpenFlags = osl_File_OpenFlag_Read | osl_File_OpenFlag_Write | osl_File_OpenFlag_Create;
        const osl::File::RC rcOpen = m_MapFile.open( nOpenFlags);
        m_bIsOpen = (rcOpen == osl::File::E_None);
        m_bToBeCreated = !m_bIsOpen;
    }
    if( !m_bIsOpen)
        return;

    // write header magic
    m_MapFile.setPos( osl_Pos_Absolut, 0);
    sal_uInt64 nBytesWritten = 0;
    m_MapFile.write( PmapMagic, sizeof(PmapMagic), nBytesWritten);

    // write key value pairs
    t_string2string_map::const_iterator it = m_entries.begin();
    for(; it != m_entries.end(); ++it) {
        // write line for key
        const OString aKeyString = encodeString( (*it).first);
        const sal_Int32 nKeyLen = aKeyString.getLength();
        m_MapFile.write( aKeyString.getStr(), nKeyLen, nBytesWritten);
        OSL_ASSERT( nKeyLen == (sal_Int32)nBytesWritten);
        m_MapFile.write( "\n", 1, nBytesWritten);
        // write line for value
        const OString& rValString = encodeString( (*it).second);
        const sal_Int32 nValLen = rValString.getLength();
        m_MapFile.write( rValString.getStr(), nValLen, nBytesWritten);
        OSL_ASSERT( nValLen == (sal_Int32)nBytesWritten);
        m_MapFile.write( "\n", 1, nBytesWritten);
    }

    // write a file delimiter (an empty key-string)
    m_MapFile.write( "\n", 1, nBytesWritten);
    // truncate file here
    sal_uInt64 nNewFileSize;
    if( m_MapFile.getPos( nNewFileSize) == osl::File::E_None)
        m_MapFile.setSize( nNewFileSize);
    // flush to disk
    m_MapFile.sync();
    // the in-memory map now matches to the file on disk
    m_bIsDirty = false;
}

//______________________________________________________________________________
bool PersistentMap::has( OString const & key ) const
{
    return get( NULL, key );
}

//______________________________________________________________________________
bool PersistentMap::get( OString * value, OString const & key ) const
{
    t_string2string_map::const_iterator it = m_entries.find( key);
    if( it == m_entries.end())
        return false;
    if( value)
        *value = it->second;
    return true;
}

//______________________________________________________________________________
void PersistentMap::add( OString const & key, OString const & value )
{
    if( m_bReadOnly)
        return;
    typedef std::pair<t_string2string_map::iterator,bool> InsertRC;
    InsertRC r = m_entries.insert( t_string2string_map::value_type(key,value));
    m_bIsDirty = r.second;
}

//______________________________________________________________________________
void PersistentMap::put( OString const & key, OString const & value )
{
    add( key, value);
    // HACK: flush now as the extension manager does not seem
    //       to properly destruct this object in some situations
    if( m_bIsDirty)
        flush();
}

//______________________________________________________________________________
bool PersistentMap::erase( OString const & key, bool flush_immediately )
{
    if( m_bReadOnly)
        return false;
    size_t nCount = m_entries.erase( key);
    if( !nCount)
        return false;
    m_bIsDirty = true;
    if( flush_immediately)
        flush();
    return true;
}

//______________________________________________________________________________
t_string2string_map PersistentMap::getEntries() const
{
    // TODO: return by const reference instead?
    return m_entries;
}

}