ogrvrtlayer.cpp

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

/******************************************************************************
 * $Id: ogrvrtlayer.cpp,v 1.10 2005/02/22 12:50:10 fwarmerdam Exp $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRVRTLayer class.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 2003, Frank Warmerdam <[e-mail]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ******************************************************************************
 *
 * $Log: ogrvrtlayer.cpp,v $
 * Revision 1.10  2005/02/22 12:50:10  fwarmerdam
 * use OGRLayer base spatial filter support
 *
 * Revision 1.9  2005/02/02 20:54:27  fwarmerdam
 * track m_nFeaturesRead
 *
 * Revision 1.8  2004/10/30 04:54:54  fwarmerdam
 * Improved geometry check error message.
 *
 * Revision 1.7  2004/10/30 04:44:00  fwarmerdam
 * Fixed error report when fetching layer.
 *
 * Revision 1.6  2004/10/16 21:56:36  fwarmerdam
 * Fixed initialization of "z".
 *
 * Revision 1.5  2004/03/25 13:23:41  warmerda
 * Fixed typo in error message.
 *
 * Revision 1.4  2003/12/30 18:34:57  warmerda
 * Added support for SrcSQL instead of SrcLayer.
 *
 * Revision 1.3  2003/11/10 20:11:55  warmerda
 * Allow any UserInput in LayerSYS
 *
 * Revision 1.2  2003/11/07 21:55:12  warmerda
 * complete fid support, relative dsname, fixes
 *
 * Revision 1.1  2003/11/07 17:50:36  warmerda
 * New
 *
 */

#include "cpl_conv.h"
#include "ogr_vrt.h"
#include "cpl_string.h"

CPL_CVSID("$Id: ogrvrtlayer.cpp,v 1.10 2005/02/22 12:50:10 fwarmerdam Exp $");

typedef struct 
{
    OGRwkbGeometryType  eType;
    const char          *pszName;
} OGRGeomTypeName;

static OGRGeomTypeName asGeomTypeNames[] = { /* 25D versions are implicit */
    { wkbUnknown, "wkbUnknown" },
    { wkbPoint, "wkbPoint" },
    { wkbLineString, "wkbLineString" },
    { wkbPolygon, "wkbPolygon" },
    { wkbMultiPoint, "wkbMultiPoint" },
    { wkbMultiLineString, "wkbLineString" },
    { wkbMultiPolygon, "wkbPolygon" },
    { wkbGeometryCollection, "wkbGeometryCollection" },
    { wkbNone, "wkbNone" },
    { wkbLinearRing, "wkbLinearRing" },
    { wkbNone, NULL }
};

/************************************************************************/
/*                            OGRVRTLayer()                             */
/************************************************************************/

OGRVRTLayer::OGRVRTLayer()

{
    poFeatureDefn = NULL;
    pszQuery = NULL;
    poSrcLayer = NULL;
    poSRS = NULL;

    iFIDField = -1;

    eGeometryType = VGS_Direct;
    iGeomField = iGeomXField = iGeomYField = iGeomZField = -1;
    
    panSrcField = NULL;
    pabDirectCopy = NULL;

    bNeedReset = TRUE;
}

/************************************************************************/
/*                            ~OGRVRTLayer()                            */
/************************************************************************/

OGRVRTLayer::~OGRVRTLayer()

{
    if( m_nFeaturesRead > 0 && poFeatureDefn != NULL )
    {
        CPLDebug( "VRT", "%d features read on layer '%s'.",
                  (int) m_nFeaturesRead, 
                  poFeatureDefn->GetName() );
    }

    if( poSRS != NULL )
        poSRS->Dereference();

    if( poSrcDS != NULL )
    {
        OGRSFDriverRegistrar::GetRegistrar()->ReleaseDataSource( poSrcDS );
    }

    delete poFeatureDefn;

    CPLFree( panSrcField );
    CPLFree( pabDirectCopy );
}

/************************************************************************/
/*                             Initialize()                             */
/************************************************************************/

int OGRVRTLayer::Initialize( CPLXMLNode *psLTree, const char *pszVRTDirectory )

{
    
    if( !EQUAL(psLTree->pszValue,"OGRVRTLayer") )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Get layer name.                                                 */
/* -------------------------------------------------------------------- */
    const char *pszLayerName = CPLGetXMLValue( psLTree, "name", NULL );

    if( pszLayerName == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Missing name attribute on OGRVRTLayer" );
        return FALSE;
    }

    poFeatureDefn = new OGRFeatureDefn( pszLayerName );

/* -------------------------------------------------------------------- */
/*      Figure out the data source name.  It may be treated relative    */
/*      to vrt filename, but normally it is used directly.              */
/* -------------------------------------------------------------------- */
    OGRSFDriverRegistrar *poReg = OGRSFDriverRegistrar::GetRegistrar();
    char *pszSrcDSName = (char *) CPLGetXMLValue(psLTree,"SrcDataSource",NULL);

    if( pszSrcDSName == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Missing SrcDataSource for layer %s.", pszLayerName );
        return FALSE;
    }

    if( atoi(CPLGetXMLValue( psLTree, "SrcDataSource.relativetoVRT", "0")) )
    {
        pszSrcDSName = CPLStrdup(
            CPLProjectRelativeFilename( pszVRTDirectory, pszSrcDSName ) );
    }
    else
    {
        pszSrcDSName = CPLStrdup(pszSrcDSName);
    }

/* -------------------------------------------------------------------- */
/*      Try to access the datasource.                                   */
/* -------------------------------------------------------------------- */
    CPLErrorReset();
    poSrcDS = poReg->OpenShared( pszSrcDSName, FALSE, NULL );

    if( poSrcDS == NULL ) 
    {
        if( strlen(CPLGetLastErrorMsg()) == 0 )
            CPLError( CE_Failure, CPLE_AppDefined, 
                      "Failed to open datasource `%s'.", 
                      pszSrcDSName );
        CPLFree( pszSrcDSName );
        return FALSE;
    }

/* -------------------------------------------------------------------- */
/*      Is this layer derived from an SQL query result?                 */
/* -------------------------------------------------------------------- */
    const char *pszSQL = CPLGetXMLValue( psLTree, "SrcSQL", NULL );

    if( pszSQL != NULL )
    {
        poSrcLayer = poSrcDS->ExecuteSQL( pszSQL, NULL, NULL );
        if( poSrcLayer == NULL )
        {
            CPLError( CE_Failure, CPLE_AppDefined,
                      "SQL statement failed, or returned no layer result:\n%s",
                      pszSQL );					      
            return FALSE;
        }
    }

/* -------------------------------------------------------------------- */
/*      Fetch the layer if it is a regular layer.                       */
/* -------------------------------------------------------------------- */
    if( poSrcLayer == NULL )
    {
        const char *pszSrcLayerName = CPLGetXMLValue( psLTree, "SrcLayer", 
                                                      pszLayerName );
        
        poSrcLayer = poSrcDS->GetLayerByName( pszSrcLayerName );
        if( poSrcLayer == NULL )
        {
            CPLError( CE_Failure, CPLE_AppDefined,
                  "Failed to find layer '%s' on datasource '%s'.", 
                      pszSrcLayerName, pszSrcDSName );
            CPLFree( pszSrcDSName );
            return FALSE;
        }
    }
        
    CPLFree( pszSrcDSName );

/* -------------------------------------------------------------------- */
/*      Do we have a fixed geometry type?  If so use it, otherwise      */
/*      derive from the source layer.                                   */
/* -------------------------------------------------------------------- */
     const char *pszGType = CPLGetXMLValue( psLTree, "GeometryType", NULL );
     
     if( pszGType != NULL )
     {
         int iType;

         for( iType = 0; asGeomTypeNames[iType].pszName != NULL; iType++ )
         {
             if( EQUALN(pszGType, asGeomTypeNames[iType].pszName, 
                        strlen(asGeomTypeNames[iType].pszName)) )
             {
                 poFeatureDefn->SetGeomType( asGeomTypeNames[iType].eType );

                 if( strstr(pszGType,"25D") != NULL )
                     poFeatureDefn->SetGeomType( 
                         (OGRwkbGeometryType)
                         (poFeatureDefn->GetGeomType() | wkb25DBit) );
                 break;
             }
         }

         if( asGeomTypeNames[iType].pszName == NULL )
         {
             CPLError( CE_Failure, CPLE_AppDefined, 
                       "GeometryType %s not recognised.", 
                       pszGType );
             return FALSE;
         }
     }

     else
     {
         poFeatureDefn->SetGeomType(poSrcLayer->GetLayerDefn()->GetGeomType());
     }
     
/* -------------------------------------------------------------------- */
/*      For now we copy the schema directly from the source layer.      */
/* -------------------------------------------------------------------- */
     int iField;
     OGRFeatureDefn *poSrcDefn = poSrcLayer->GetLayerDefn();
     panSrcField = (int *) CPLMalloc(sizeof(int) * poSrcDefn->GetFieldCount());
     pabDirectCopy = (int *) CPLMalloc(sizeof(int)*poSrcDefn->GetFieldCount());

     for( iField = 0; iField < poSrcDefn->GetFieldCount(); iField++ )
     {
         poFeatureDefn->AddFieldDefn( poSrcDefn->GetFieldDefn( iField ) );
         panSrcField[iField] = iField;
         pabDirectCopy[iField] = TRUE;
     }
     
/* -------------------------------------------------------------------- */
/*      Apply a spatial reference system if provided, otherwise copy    */
/*      from source.                                                    */
/* -------------------------------------------------------------------- */
     const char *pszLayerSRS = CPLGetXMLValue( psLTree, "LayerSRS", NULL );

     if( pszLayerSRS != NULL )
     {
         if( EQUAL(pszLayerSRS,"NULL") )
             poSRS = NULL;
         else
         {
             OGRSpatialReference oSRS;

             if( oSRS.SetFromUserInput( pszLayerSRS ) != OGRERR_NONE )
             {
                 CPLError( CE_Failure, CPLE_AppDefined, 
                           "Failed to import LayerSRS `%s'.", pszLayerSRS );
                 return FALSE;
             }
             poSRS = oSRS.Clone();
         }
     }