ogrfmelayercached.cpp

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/******************************************************************************
 * $Id: ogrfmelayercached.cpp 10646 2007-01-18 02:38:10Z warmerdam $
 *
 * Project:  FMEObjects Translator
 * Purpose:  Implementation of the OGRFMELayerCached class.  This is the
 *           class implementing behaviour for layers that are built into a
 *           temporary spatial cache (as opposed to live read database).
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 1999, 2001 Safe Software Inc.
 * All Rights Reserved
 *
 * This software may not be copied or reproduced, in all or in part, 
 * without the prior written consent of Safe Software Inc.
 *
 * The entire risk as to the results and performance of the software,
 * supporting text and other information contained in this file
 * (collectively called the "Software") is with the user.  Although
 * Safe Software Incorporated has used considerable efforts in preparing 
 * the Software, Safe Software Incorporated does not warrant the
 * accuracy or completeness of the Software. In no event will Safe Software 
 * Incorporated be liable for damages, including loss of profits or 
 * consequential damages, arising out of the use of the Software.
 ****************************************************************************/

#include "fme2ogr.h"
#include "cpl_conv.h"
#include "cpl_string.h"

CPL_CVSID("$Id: ogrfmelayercached.cpp 10646 2007-01-18 02:38:10Z warmerdam $");

/************************************************************************/
/*                         OGRFMELayerCached()                          */
/************************************************************************/

OGRFMELayerCached::OGRFMELayerCached( OGRFMEDataSource *poDSIn ) 
        : OGRFMELayer( poDSIn )

{
    nPreviousFeature = -1;

    pszIndexBase = NULL;
    poIndex = NULL;

    memset( &sExtents, 0, sizeof(sExtents) );

    bQueryActive = FALSE;
}

/************************************************************************/
/*                         ~OGRFMELayerCached()                         */
/************************************************************************/

OGRFMELayerCached::~OGRFMELayerCached()

{
    CPLFree( pszIndexBase );
    if( poIndex != NULL )
    {
#ifdef SUPPORT_PERSISTENT_CACHE
        poIndex->close( FME_FALSE );
#else
        poIndex->close( FME_TRUE );
#endif
        poDS->GetFMESession()->destroySpatialIndex( poIndex );
    }
}

/************************************************************************/
/*                            AssignIndex()                             */
/*                                                                      */
/*      Assign spatial index .. spatial index is opened for read        */
/*      access.                                                         */
/************************************************************************/

int OGRFMELayerCached::AssignIndex( const char *pszBase,
                                    const OGREnvelope *psExtents,
                                    OGRSpatialReference *poSRS )
    
{
    CPLAssert( poIndex == NULL );
    
    pszIndexBase = CPLStrdup( pszBase );
    poIndex = 
        poDS->GetFMESession()->createSpatialIndex( pszBase, "READ", NULL );
    if( poIndex == NULL )
        return FALSE;
    if( poIndex->open() != 0 )
    {
        poDS->GetFMESession()->destroySpatialIndex( poIndex );
        poIndex = NULL;
        return FALSE;
    }

    if( psExtents != NULL )
        sExtents = *psExtents;

    if( poSRS != NULL )
    {
        if( poSpatialRef != NULL )
            delete poSpatialRef;
        poSpatialRef = poSRS;
    }

    return TRUE;
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRFMELayerCached::TestCapability( const char * pszCap )

{
    if( EQUAL(pszCap,OLCRandomRead) )
        return FALSE;

    else if( EQUAL(pszCap,OLCSequentialWrite) 
             || EQUAL(pszCap,OLCRandomWrite) )
        return FALSE;

    else if( EQUAL(pszCap,OLCFastFeatureCount) )
        return TRUE;

    else if( EQUAL(pszCap,OLCFastSpatialFilter) )
        return TRUE;

    else if( EQUAL(pszCap,OLCFastGetExtent) )
        return TRUE;

    else 
        return FALSE;
}

/************************************************************************/
/*                        ReadNextIndexFeature()                        */
/************************************************************************/

OGRFeature *OGRFMELayerCached::ReadNextIndexFeature()

{
    OGRFeature          *poOGRFeature = NULL;
    FME_Boolean         endOfQuery;

    if( poIndex == NULL )
        return NULL;

    if( !bQueryActive )
        ResetReading();

    poDS->AcquireSession();

    if( poIndex->fetch( *poFMEFeature, endOfQuery ) == 0
        && !endOfQuery )
    {
        poOGRFeature = poDS->ProcessFeature( this, poFMEFeature );

        if( poOGRFeature != NULL )
        {
            poOGRFeature->SetFID( ++nPreviousFeature );
            m_nFeaturesRead++;
        }
    }

    poDS->ReleaseSession();

    return poOGRFeature;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/************************************************************************/

OGRFeature *OGRFMELayerCached::GetNextFeature()

{
    OGRFeature      *poFeature;

    while( TRUE ) 
    {
        poFeature = ReadNextIndexFeature();

        if( poFeature != NULL )
            nPreviousFeature = poFeature->GetFID();
        else
            break;

        if( m_poAttrQuery == NULL 
            || poIndex == NULL
            || m_poAttrQuery->Evaluate( poFeature ) )
            break;

        delete poFeature;
    }

    return poFeature;
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/
 
void OGRFMELayerCached::ResetReading()

{
    nPreviousFeature = -1;

    if( poIndex == NULL )
    {
        CPLAssert( FALSE );
        return;
    }

    poDS->AcquireSession();

    if( m_poFilterGeom == NULL )
    {
        poIndex->queryAll();
    }
    else
    {
        OGREnvelope      oEnvelope;

        m_poFilterGeom->getEnvelope( &oEnvelope );

        poFMEFeature->resetFeature();

        poFMEFeature->setDimension( FME_TWO_D );
        poFMEFeature->setGeometryType( FME_GEOM_LINE );
        poFMEFeature->addCoordinate( oEnvelope.MinX, oEnvelope.MinY );
        poFMEFeature->addCoordinate( oEnvelope.MaxX, oEnvelope.MaxY );
            
        poIndex->queryEnvelope( *poFMEFeature );
    }

    bQueryActive = TRUE;

    poDS->ReleaseSession();
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/************************************************************************/