ogrdatasource.cpp

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

                  pszSQLCommand );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Attempt to drop the index.                                      */
/* -------------------------------------------------------------------- */
    eErr = poLayer->GetIndex()->DropIndex( i );

    return eErr;
}

/************************************************************************/
/*                             ExecuteSQL()                             */
/************************************************************************/

OGRLayer * OGRDataSource::ExecuteSQL( const char *pszStatement,
                                      OGRGeometry *poSpatialFilter,
                                      const char *pszDialect )

{
    const char *pszError;
    swq_select *psSelectInfo = NULL;

    (void) pszDialect;

/* -------------------------------------------------------------------- */
/*      Handle CREATE INDEX statements specially.                       */
/* -------------------------------------------------------------------- */
    if( EQUALN(pszStatement,"CREATE INDEX",12) )
    {
        ProcessSQLCreateIndex( pszStatement );
        return NULL;
    }
    
/* -------------------------------------------------------------------- */
/*      Handle DROP INDEX statements specially.                         */
/* -------------------------------------------------------------------- */
    if( EQUALN(pszStatement,"DROP INDEX",10) )
    {
        ProcessSQLDropIndex( pszStatement );
        return NULL;
    }
    
/* -------------------------------------------------------------------- */
/*      Preparse the SQL statement.                                     */
/* -------------------------------------------------------------------- */
    pszError = swq_select_preparse( pszStatement, &psSelectInfo );
    if( pszError != NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "SQL: %s", pszError );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Validate that all the source tables are recognised, count       */
/*      fields.                                                         */
/* -------------------------------------------------------------------- */
    int  nFieldCount = 0, iTable;

    for( iTable = 0; iTable < psSelectInfo->table_count; iTable++ )
    {
        swq_table_def *psTableDef = psSelectInfo->table_defs + iTable;
        OGRLayer *poSrcLayer;
        OGRDataSource *poTableDS = this;

        if( psTableDef->data_source != NULL )
        {
            poTableDS = (OGRDataSource *) 
                OGROpenShared( psTableDef->data_source, FALSE, NULL );
            if( poTableDS == NULL )
            {
                if( strlen(CPLGetLastErrorMsg()) == 0 )
                    CPLError( CE_Failure, CPLE_AppDefined, 
                              "Unable to open secondary datasource\n"
                              "`%s' required by JOIN.",
                              psTableDef->data_source );

                swq_select_free( psSelectInfo );
                return NULL;
            }

            // This drops explicit reference, but leave it open for use by
            // code in ogr_gensql.cpp
            poTableDS->Dereference();
        }

        poSrcLayer = poTableDS->GetLayerByName( psTableDef->table_name );

        if( poSrcLayer == NULL )
        {
            CPLError( CE_Failure, CPLE_AppDefined, 
                      "SELECT from table %s failed, no such table/featureclass.",
                      psTableDef->table_name );
            swq_select_free( psSelectInfo );
            return NULL;
        }

        nFieldCount += poSrcLayer->GetLayerDefn()->GetFieldCount();
    }
    
/* -------------------------------------------------------------------- */
/*      Build the field list for all indicated tables.                  */
/* -------------------------------------------------------------------- */
    swq_field_list sFieldList;
    int            nFIDIndex = 0;

    memset( &sFieldList, 0, sizeof(sFieldList) );
    sFieldList.table_count = psSelectInfo->table_count;
    sFieldList.table_defs = psSelectInfo->table_defs;

    sFieldList.count = 0;
    sFieldList.names = (char **) CPLMalloc( sizeof(char *) * (nFieldCount+1) );
    sFieldList.types = (swq_field_type *)  
        CPLMalloc( sizeof(swq_field_type) * (nFieldCount+1) );
    sFieldList.table_ids = (int *) 
        CPLMalloc( sizeof(int) * (nFieldCount+1) );
    sFieldList.ids = (int *) 
        CPLMalloc( sizeof(int) * (nFieldCount+1) );
    
    for( iTable = 0; iTable < psSelectInfo->table_count; iTable++ )
    {
        swq_table_def *psTableDef = psSelectInfo->table_defs + iTable;
        OGRDataSource *poTableDS = this;
        OGRLayer *poSrcLayer;
        int      iField;

        if( psTableDef->data_source != NULL )
        {
            poTableDS = (OGRDataSource *) 
                OGROpenShared( psTableDef->data_source, FALSE, NULL );
            CPLAssert( poTableDS != NULL );
            poTableDS->Dereference();
        }

        poSrcLayer = poTableDS->GetLayerByName( psTableDef->table_name );

        for( iField = 0; 
             iField < poSrcLayer->GetLayerDefn()->GetFieldCount();
             iField++ )
        {
            OGRFieldDefn *poFDefn=poSrcLayer->GetLayerDefn()->GetFieldDefn(iField);
            int iOutField = sFieldList.count++;
            sFieldList.names[iOutField] = (char *) poFDefn->GetNameRef();
            if( poFDefn->GetType() == OFTInteger )
                sFieldList.types[iOutField] = SWQ_INTEGER;
            else if( poFDefn->GetType() == OFTReal )
                sFieldList.types[iOutField] = SWQ_FLOAT;
            else if( poFDefn->GetType() == OFTString )
                sFieldList.types[iOutField] = SWQ_STRING;
            else
                sFieldList.types[iOutField] = SWQ_OTHER;

            sFieldList.table_ids[iOutField] = iTable;
            sFieldList.ids[iOutField] = iField;
        }

        if( iTable == 0 )
            nFIDIndex = poSrcLayer->GetLayerDefn()->GetFieldCount();
    }

/* -------------------------------------------------------------------- */
/*      Expand '*' in 'SELECT *' now before we add the pseudo field     */
/*      'FID'.                                                          */
/* -------------------------------------------------------------------- */
    pszError = 
        swq_select_expand_wildcard( psSelectInfo, &sFieldList );

    if( pszError != NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "SQL: %s", pszError );
        return NULL;
    }

    sFieldList.names[sFieldList.count] = "FID";
    sFieldList.types[sFieldList.count] = SWQ_INTEGER;
    sFieldList.table_ids[sFieldList.count] = 0;
    sFieldList.ids[sFieldList.count] = nFIDIndex;
    
    sFieldList.count++;

/* -------------------------------------------------------------------- */
/*      Finish the parse operation.                                     */
/* -------------------------------------------------------------------- */
    
    pszError = swq_select_parse( psSelectInfo, &sFieldList, 0 );

    CPLFree( sFieldList.names );
    CPLFree( sFieldList.types );
    CPLFree( sFieldList.table_ids );
    CPLFree( sFieldList.ids );

    if( pszError != NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "SQL: %s", pszError );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Everything seems OK, try to instantiate a results layer.        */
/* -------------------------------------------------------------------- */
    OGRGenSQLResultsLayer *poResults;

    poResults = new OGRGenSQLResultsLayer( this, psSelectInfo, 
                                           poSpatialFilter );

    // Eventually, we should keep track of layers to cleanup.

    return poResults;
}

/************************************************************************/
/*                         OGR_DS_ExecuteSQL()                          */
/************************************************************************/

OGRLayerH OGR_DS_ExecuteSQL( OGRDataSourceH hDS, 
                             const char *pszStatement,
                             OGRGeometryH hSpatialFilter,
                             const char *pszDialect )

{
    return (OGRLayerH) 
        ((OGRDataSource *)hDS)->ExecuteSQL( pszStatement,
                                            (OGRGeometry *) hSpatialFilter,
                                            pszDialect );
}

/************************************************************************/
/*                          ReleaseResultSet()                          */
/************************************************************************/

void OGRDataSource::ReleaseResultSet( OGRLayer * poResultsSet )

{
    delete poResultsSet;
}

/************************************************************************/
/*                      OGR_DS_ReleaseResultSet()                       */
/************************************************************************/

void OGR_DS_ReleaseResultSet( OGRDataSourceH hDS, OGRLayerH hLayer )

{
    ((OGRDataSource *) hDS)->ReleaseResultSet( (OGRLayer *) hLayer );
}

/************************************************************************/
/*                       OGR_DS_TestCapability()                        */
/************************************************************************/

int OGR_DS_TestCapability( OGRDataSourceH hDS, const char *pszCap )

{
    return ((OGRDataSource *) hDS)->TestCapability( pszCap );
}

/************************************************************************/
/*                        OGR_DS_GetLayerCount()                        */
/************************************************************************/

int OGR_DS_GetLayerCount( OGRDataSourceH hDS )

{
    return ((OGRDataSource *)hDS)->GetLayerCount();
}

/************************************************************************/
/*                          OGR_DS_GetLayer()                           */
/************************************************************************/

OGRLayerH OGR_DS_GetLayer( OGRDataSourceH hDS, int iLayer )

{
    return (OGRLayerH) ((OGRDataSource*)hDS)->GetLayer( iLayer );
}

/************************************************************************/
/*                           OGR_DS_GetName()                           */
/************************************************************************/

const char *OGR_DS_GetName( OGRDataSourceH hDS )

{
    return ((OGRDataSource*)hDS)->GetName();
}

/************************************************************************/
/*                             SyncToDisk()                             */
/************************************************************************/

OGRErr OGRDataSource::SyncToDisk()

{
    int i;
    OGRErr eErr;

    for( i = 0; i < GetLayerCount(); i++ )
    {
        OGRLayer *poLayer = GetLayer(i);

        if( poLayer )
        {
            eErr = poLayer->SyncToDisk();
            if( eErr != OGRERR_NONE )
                return eErr;
        }
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                         OGR_DS_SyncToDisk()                          */
/************************************************************************/

OGRErr OGR_DS_SyncToDisk( OGRDataSourceH hDS )

{
    return ((OGRDataSource *) hDS)->SyncToDisk();
}