ogrfmecacheindex.cpp

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

        }

        if( iDir < (int) oUserDirectives.entries() || !bMatch 
            || (psDirective != NULL && psDirective->psNext != NULL) )
            continue;

        return psCDS;
    }

    return NULL;
}

/************************************************************************/
/*                               Touch()                                */
/*                                                                      */
/*      Update the LastUseTime on the passed datasource.                */
/************************************************************************/

void OGRFMECacheIndex::Touch( CPLXMLNode *psDSNode )

{
    if( psDSNode == NULL || !EQUAL(psDSNode->pszValue,"DataSource") )
        return;

/* -------------------------------------------------------------------- */
/*      Prepare the new time value to use.                              */
/* -------------------------------------------------------------------- */
    char      szNewTime[32];

    sprintf( szNewTime, "%lu", (unsigned long) time(NULL) );

/* -------------------------------------------------------------------- */
/*      Set or insert LastUseTime into dataset.                         */
/* -------------------------------------------------------------------- */
    CPLSetXMLValue( psDSNode, "LastUseTime", szNewTime );
}

/************************************************************************/
/*                             Reference()                              */
/************************************************************************/

void OGRFMECacheIndex::Reference( CPLXMLNode *psDSNode )

{
    if( psDSNode == NULL || !EQUAL(psDSNode->pszValue,"DataSource") )
        return;

    char szNewRefCount[32];

    sprintf( szNewRefCount, "%d", 
             atoi(CPLGetXMLValue(psDSNode, "RefCount", "0")) + 1 );

    CPLSetXMLValue( psDSNode, "RefCount", szNewRefCount );

    Touch( psDSNode );
}

/************************************************************************/
/*                            Dereference()                             */
/************************************************************************/

void OGRFMECacheIndex::Dereference( CPLXMLNode *psDSNode )

{
    if( psDSNode == NULL 
        || !EQUAL(psDSNode->pszValue,"DataSource") 
        || CPLGetXMLNode(psDSNode,"RefCount") == NULL )
        return;

    char szNewRefCount[32];
    int  nRefCount = atoi(CPLGetXMLValue(psDSNode, "RefCount", "1"));
    if( nRefCount < 1 )
        nRefCount = 1;

    sprintf( szNewRefCount, "%d", nRefCount-1 );

    CPLSetXMLValue( psDSNode, "RefCount", szNewRefCount );

    Touch( psDSNode );
}

/************************************************************************/
/*                                Add()                                 */
/*                                                                      */
/*      Note that Add() takes over ownership of the passed tree.        */
/************************************************************************/

void OGRFMECacheIndex::Add( CPLXMLNode *psDSNode )

{
    CPLAssert( psTree != NULL );

    psDSNode->psNext = psTree->psChild;
    psTree->psChild = psDSNode;

    if( psDSNode == NULL || !EQUAL(psDSNode->pszValue,"DataSource") )
        return;

/* -------------------------------------------------------------------- */
/*      Prepare the creation time value to use.                         */
/* -------------------------------------------------------------------- */
    char      szNewTime[32];

    sprintf( szNewTime, "%lu", (unsigned long) time(NULL) );

/* -------------------------------------------------------------------- */
/*      Set or insert CreationTime into dataset.                        */
/* -------------------------------------------------------------------- */
    CPLSetXMLValue( psDSNode, "CreationTime", szNewTime );
}

/************************************************************************/
/*                          ExpireOldCaches()                           */
/*                                                                      */
/*      Make a pass over all the cache index entries.  Remove (and      */
/*      free the associated FME spatial caches) for any entries that    */
/*      haven't been touched for a long time.  Note that two            */
/*      different timeouts apply.  One is for layers with a RefCount    */
/*      of 0 and the other (longer time) is for those with a            */
/*      non-zero refcount.  Even if the RefCount is non-zero we         */
/*      assume this may because a program crashed during it's run.      */
/************************************************************************/

int OGRFMECacheIndex::ExpireOldCaches( IFMESession *poSession )

{
    CPLXMLNode *psDSNode, *psLastDSNode = NULL;
    unsigned long nCurTime = time(NULL);
    int  bChangeMade = FALSE;

    if( psTree == NULL )
        return FALSE;

    for( psLastDSNode = NULL; TRUE; psLastDSNode = psDSNode )
    {
        if( psLastDSNode != NULL )
            psDSNode = psLastDSNode->psNext;
        else
            psDSNode = psTree->psChild;
        if( psDSNode == NULL )
            break;

        if( !EQUAL(psDSNode->pszValue,"DataSource") )
            continue;
        
/* -------------------------------------------------------------------- */
/*      When was this datasource last accessed?                         */
/* -------------------------------------------------------------------- */
        unsigned long nLastUseTime = 0;

        sscanf( CPLGetXMLValue( psDSNode, "LastUseTime", "0" ), 
                "%lu", &nLastUseTime );
        
/* -------------------------------------------------------------------- */
/*      When was this datasource created.                               */
/* -------------------------------------------------------------------- */
        unsigned long nCreationTime = 0;

        sscanf( CPLGetXMLValue( psDSNode, "CreationTime", "0" ), 
                "%lu", &nCreationTime );

/* -------------------------------------------------------------------- */
/*      Do we want to delete this datasource according to our           */
/*      retention and ref timeout rules?                                */
/* -------------------------------------------------------------------- */
        int bCleanup = FALSE;

        // Do we want to cleanup this node? 
        if( atoi(CPLGetXMLValue( psDSNode, "RefCount", "0" )) > 0 
             && nLastUseTime + FMECACHE_REF_TIMEOUT < nCurTime )
            bCleanup = TRUE;

        if( atoi(CPLGetXMLValue( psDSNode, "RefCount", "0" )) < 1 
            && nLastUseTime + FMECACHE_RETENTION < nCurTime )
            bCleanup = TRUE;

        if( atoi(CPLGetXMLValue( psDSNode, "RefCount", "0" )) < 1 
            && nCreationTime + FMECACHE_MAX_RETENTION < nCurTime )
            bCleanup = TRUE;

        if( !bCleanup )
            continue;

        bChangeMade = TRUE;

        CPLDebug( "OGRFMECacheIndex", 
                  "ExpireOldCaches() cleaning up data source %s - %ds since last use, %ds old.",
                  CPLGetXMLValue( psDSNode, "DSName", "<missing name>" ),
                  nCurTime - nLastUseTime,
                  nCurTime - nCreationTime );

/* -------------------------------------------------------------------- */
/*      Loop over all the layers, to delete the spatial caches on       */
/*      disk.                                                           */
/* -------------------------------------------------------------------- */
        CPLXMLNode *psLayerN;

        for( psLayerN = psDSNode->psChild; 
             psLayerN != NULL;
             psLayerN = psLayerN->psNext )
        {
            IFMESpatialIndex   *poIndex;

            if( !EQUAL(psLayerN->pszValue,"OGRLayer") )
                continue;

            const char *pszBase;

            pszBase = CPLGetXMLValue( psLayerN, "SpatialCacheName", "" );
            if( EQUAL(pszBase,"") )
                continue;

            // open, and then delete the index on close.
            poIndex = poSession->createSpatialIndex( pszBase, "READ", NULL );

            if( poIndex == NULL )
                continue;

            if( poIndex->open() != 0 )
            {
                CPLDebug( "OGRFMECacheIndex", "Failed to open FME index %s.",
                          pszBase );
                          
                poSession->destroySpatialIndex( poIndex );
                continue;
            }
         
            poIndex->close( FME_TRUE );
            poSession->destroySpatialIndex( poIndex );
        }

/* -------------------------------------------------------------------- */
/*      Remove the datasource from the tree.                            */
/* -------------------------------------------------------------------- */
        if( psLastDSNode == NULL )
            psTree->psChild = psDSNode->psNext;
        else
            psLastDSNode->psNext = psDSNode->psNext;

        psDSNode->psNext = NULL;
        CPLDestroyXMLNode( psDSNode );
        psDSNode = psLastDSNode;
    }

    return bChangeMade;
}