ogrgrasslayer.cpp

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/******************************************************************************
 * $Id: ogrgrasslayer.cpp 10646 2007-01-18 02:38:10Z warmerdam $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRGRASSLayer class.
 * Author:   Radim Blazek, [e-mail] 
 *
 ******************************************************************************
 * Copyright (c) 2005, Radim Blazek <[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.
 ****************************************************************************/

#include <signal.h>
#include "ogrgrass.h"
#include "cpl_conv.h"

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

/************************************************************************/
/*                           OGRGRASSLayer()                            */
/************************************************************************/
OGRGRASSLayer::OGRGRASSLayer( int layerIndex,  struct Map_info * map )
{
    CPLDebug ( "GRASS", "OGRGRASSLayer::OGRGRASSLayer layerIndex = %d", layerIndex );
    
    iLayerIndex = layerIndex;
    poMap = map; 
    poSRS = NULL;
    iNextId = 0;
    poPoints = Vect_new_line_struct();
    poCats = Vect_new_cats_struct();
    pszQuery = NULL;
    paQueryMatch = NULL;
    paSpatialMatch = NULL;

    iLayer = Vect_cidx_get_field_number ( poMap, iLayerIndex);
    CPLDebug ( "GRASS", "iLayer = %d", iLayer );
    
    poLink = Vect_get_field ( poMap, iLayer ); // May be NULL if not defined

    // Layer name
    if ( poLink && poLink->name )
    {
	pszName = CPLStrdup( poLink->name );	
    }
    else
    {	
	char buf[20]; 
	sprintf ( buf, "%d", iLayer ); 
	pszName = CPLStrdup( buf );
    }

    // Because we don't represent centroids as any simple feature, we have to scan
    // category index and create index of feature IDs pointing to category index
    nTotalCount = Vect_cidx_get_type_count(poMap,iLayer, GV_POINT|GV_LINES|GV_AREA);
    CPLDebug ( "GRASS", "nTotalCount = %d", nTotalCount );
    paFeatureIndex = (int *) CPLMalloc ( nTotalCount * sizeof(int) );
    
    int n = Vect_cidx_get_type_count(poMap,iLayer, GV_POINTS|GV_LINES|GV_AREA);
    int cnt = 0;
    for ( int i = 0; i < n; i++ ) 
    {
	int cat,type, id;
	
	Vect_cidx_get_cat_by_index ( poMap, iLayerIndex, i, &cat, &type, &id );
    
	if ( !( type & (GV_POINT|GV_LINES|GV_AREA) ) ) continue;
	paFeatureIndex[cnt++] = i;
    }

    poFeatureDefn = new OGRFeatureDefn( pszName );
    poFeatureDefn->Reference();

    // Get type definition
    int nTypes = Vect_cidx_get_num_types_by_index ( poMap, iLayerIndex );
    int types = 0;
    for ( int i = 0; i < nTypes; i++ ) {
	int type, count;
	Vect_cidx_get_type_count_by_index ( poMap, iLayerIndex, i, &type, &count);
	if ( !(type & (GV_POINT|GV_LINES|GV_AREA) ) ) continue;
	types |= type;
        CPLDebug ( "GRASS", "type = %d types = %d", type, types );
    }
    if ( types == GV_LINE || types == GV_BOUNDARY || types == GV_LINES ) 
    {
        poFeatureDefn->SetGeomType ( wkbLineString );
    } 
    else if ( types == GV_POINT )
    {
	poFeatureDefn->SetGeomType ( wkbPoint );
    }
    else if ( types == GV_AREA )
    {
        CPLDebug ( "GRASS", "set wkbPolygon" );
	poFeatureDefn->SetGeomType ( wkbPolygon );
    }

    // Get attributes definition
    poDbString = (dbString*) CPLMalloc ( sizeof(dbString) );
    poCursor = (dbCursor*) CPLMalloc ( sizeof(dbCursor) );
    bCursorOpened = FALSE;

    poDriver = NULL;
    bHaveAttributes = false;
    db_init_string ( poDbString );
    if ( poLink ) 
    {
	if ( StartDbDriver() ) 
	{
	    db_set_string ( poDbString, poLink->table );
	    dbTable *table;
	    if ( db_describe_table ( poDriver, poDbString, &table) == DB_OK )
	    {
		nFields = db_get_table_number_of_columns ( table );
		iCatField = -1;
		for ( int i = 0; i < nFields; i++) 
		{
		    dbColumn *column = db_get_table_column ( table, i );
		    int ctype = db_sqltype_to_Ctype ( db_get_column_sqltype(column) );
    
		    OGRFieldType ogrFtype = OFTInteger;
 	     	    switch ( ctype ) {
			 case DB_C_TYPE_INT:
			    ogrFtype = OFTInteger;
			    break; 
			 case DB_C_TYPE_DOUBLE:
			    ogrFtype = OFTReal;
			    break; 
			 case DB_C_TYPE_STRING:
			    ogrFtype = OFTString;
			    break; 
			 case DB_C_TYPE_DATETIME:
			    ogrFtype = OFTDateTime;
			    break; 
		    }

		    CPLDebug ( "GRASS", "column = %s type = %d", 
			       db_get_column_name(column), ctype );
		    
		    OGRFieldDefn oField ( db_get_column_name(column), ogrFtype );
		    poFeatureDefn->AddFieldDefn( &oField );

		    if ( G_strcasecmp(db_get_column_name(column),poLink->key) == 0 )
		    {
			iCatField = i;
		    }
		}
		if ( iCatField >= 0  ) 
		{
    		    bHaveAttributes = true;
		}
		else
		{
		    CPLError( CE_Failure, CPLE_AppDefined, "Cannot find key field" );
		    db_close_database_shutdown_driver ( poDriver );
		    poDriver = NULL;
		}
	    }
	    else
	    {
		CPLError( CE_Failure, CPLE_AppDefined, "Cannot describe table %s", 
			  poLink->table );

	    }
	    db_close_database_shutdown_driver ( poDriver );
	    poDriver = NULL;
	}
    } 
	
    if ( !bHaveAttributes && iLayer > 0 ) // Because features in layer 0 have no cats  
    {
	OGRFieldDefn oField("cat", OFTInteger);
	poFeatureDefn->AddFieldDefn( &oField );
    }

    if ( getenv("GISBASE") )  // We have some projection info in GISBASE
    {
        struct Key_Value *projinfo, *projunits;

	// Note: we dont have to reset GISDBASE and LOCATION_NAME because 
	// OGRGRASSLayer constructor is called from OGRGRASSDataSource::Open
	// where those variables are set

        projinfo = G_get_projinfo();
	projunits = G_get_projunits();

	char *srsWkt = GPJ_grass_to_wkt ( projinfo, projunits, 0, 0);
	if ( srsWkt ) 
	{
	    poSRS = new OGRSpatialReference ( srsWkt );
	    CPLFree ( srsWkt );
	}
    }
}

/************************************************************************/
/*                           ~OGRGRASSLayer()                           */
/************************************************************************/
OGRGRASSLayer::~OGRGRASSLayer()
{
    if ( bCursorOpened ) 
    {
	db_close_cursor ( poCursor);
    }

    if ( poDriver ) 
    {
	StopDbDriver();
    }
    
    if ( pszName ) CPLFree ( pszName );
    if ( poFeatureDefn )
        poFeatureDefn->Release();
    if ( poSRS )
        poSRS->Release();

    if ( pszQuery ) CPLFree ( pszQuery );
    
    if ( paFeatureIndex ) CPLFree ( paFeatureIndex );
    
    if ( poLink ) CPLFree ( poLink );
    
    Vect_destroy_line_struct ( poPoints );
    Vect_destroy_cats_struct ( poCats );

    db_free_string ( poDbString );
    CPLFree ( poDbString );
    CPLFree ( poCursor );

    if ( paSpatialMatch ) CPLFree ( paSpatialMatch );
    if ( paQueryMatch ) CPLFree ( paQueryMatch );
}

/************************************************************************/
/*                            StartDbDriver                             */
/************************************************************************/
bool OGRGRASSLayer::StartDbDriver()
{
    CPLDebug ( "GRASS", "StartDbDriver()" ); 

    bCursorOpened = false;
	    
    if ( !poLink ) 
    {
	return false;
    }
    poDriver = db_start_driver_open_database ( poLink->driver, poLink->database );
    
    if ( poDriver == NULL) 
    {
	CPLError( CE_Failure, CPLE_AppDefined, "Cannot open database %s by driver %s, "
		  "check if GISBASE enviroment variable is set, the driver is available "
		  " and the database is accessible.", poLink->driver, poLink->database );
	return false;
    } 
    return true;
}

/************************************************************************/
/*                            StopDbDriver                              */
/************************************************************************/
bool OGRGRASSLayer::StopDbDriver()
{
    if ( !poDriver ) 
    {
	CPLError( CE_Failure, CPLE_AppDefined, "Driver is not started" );
	return true; // I think that true is OK here
    }

    // TODO!!!: Because of bug in GRASS library it is impossible 
    // to stop drivers in FIFO order. Until this is fixed 
    // we have to use kill
    CPLDebug ( "GRASS", "driver PID = %d", poDriver->pid ); 

#if defined(_WIN32) || defined(__WIN32__)
    db_close_database_shutdown_driver ( poDriver );
#else
    if ( kill (poDriver->pid, SIGINT) != 0 ) 
    {
	if ( kill (poDriver->pid, SIGKILL) != 0 ) 
	{
	    CPLError( CE_Failure, CPLE_AppDefined, "Cannot stop database "
		      "driver pid = %d", poDriver->pid );
	}
    }
#endif
	    
    bCursorOpened = false;
    
    return true;
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/
void OGRGRASSLayer::ResetReading()
{
    iNextId = 0;
    
    if ( bCursorOpened ) {
	ResetSequentialCursor();
    }
}

/************************************************************************/
/*                           SetNextByIndex()                           */
/*                                                                      */
/*      If we already have an FID list, we can easily resposition       */
/*      ourselves in it.                                                */
/************************************************************************/
OGRErr OGRGRASSLayer::SetNextByIndex( long nIndex )
{
    if( m_poFilterGeom != NULL || m_poAttrQuery != NULL ) 
    {
	iNextId = 0;
	int count = 0;
	
	while ( true ) {
	    if( iNextId >= nTotalCount ) break;
	    if ( count == nIndex ) break;

	    // Attributes
	    if( pszQuery != NULL && !paQueryMatch[iNextId] ) {
		iNextId++;
		continue;
	    }

	    // Spatial
	    if( m_poFilterGeom && !paSpatialMatch[iNextId] ) {
		iNextId++;
		continue;
	    }
	    count++;
	}
    }

    iNextId = nIndex;

    return OGRERR_NONE;
}

/************************************************************************/
/*                           SetAttributeFilter                         */
/************************************************************************/
OGRErr OGRGRASSLayer::SetAttributeFilter( const char *query )
{
    CPLDebug ( "GRASS", "SetAttributeFilter: %s", query  );

    if ( query == NULL ) {
	// Release old if any
	if ( pszQuery ) {
	    CPLFree ( pszQuery );
	    pszQuery = NULL;
	}
	if ( paQueryMatch ) {
	    CPLFree ( paQueryMatch );
	    paQueryMatch = NULL;
	}
	return OGRERR_NONE;
    }

    paQueryMatch = (char *) CPLMalloc ( nTotalCount );
    memset ( paQueryMatch, 0x0, nTotalCount );
    pszQuery = strdup ( query );

    OGRLayer::SetAttributeFilter(query); // Otherwise crash on delete

    if ( bHaveAttributes ) {

	if ( !poDriver ) 
	{
	    StartDbDriver();
	}

	if ( poDriver ) 
	{
	    if ( bCursorOpened )
	    {
		db_close_cursor ( poCursor ); 
		bCursorOpened = false;
	    }
	    OpenSequentialCursor();
	    if ( bCursorOpened )
	    {
		SetQueryMatch();
		db_close_cursor ( poCursor );
		bCursorOpened = false;
	    }
	    else
	    {
		CPLFree ( pszQuery );
		pszQuery = NULL;
		return OGRERR_FAILURE;
	    }
	    db_close_database_shutdown_driver ( poDriver );
	    poDriver = NULL;
	}
	else
	{
	    CPLFree ( pszQuery );
	    pszQuery = NULL;
	    return OGRERR_FAILURE;
	}
    }
    else
    {
	// Use OGR to evaluate category match
	for ( int i = 0; i < nTotalCount; i++ ) 
	{
	    OGRFeature *feature = GetFeature(i); 
	    CPLDebug ( "GRASS", "i = %d eval = %d", i, m_poAttrQuery->Evaluate ( feature ) );
	    if ( m_poAttrQuery->Evaluate ( feature ) )
	    {
		paQueryMatch[i] = 1;
	    }
	}
    }
    
    return OGRERR_NONE;
}

/************************************************************************/
/*                           SetQueryMatch                              */
/************************************************************************/
bool OGRGRASSLayer::SetQueryMatch()
{
    CPLDebug ( "GRASS", "SetQueryMatch" );

    // NOTE: we don't have to call ResetSequentialCursor() first because
    // this method is called immediately after OpenSequentialCursor()
    
    if ( !bCursorOpened ) {
	CPLError( CE_Failure, CPLE_AppDefined, "Cursor is not opened.");
	return false;
    }

    int more;
    int cidx = 0; // index to category index
    int fidx = 0; // index to feature index (paFeatureIndex)
    // number of categories in category index
    int ncats = Vect_cidx_get_num_cats_by_index ( poMap, iLayerIndex );
    dbTable *table = db_get_cursor_table ( poCursor );
    while ( true ) {
	if( db_fetch ( poCursor, DB_NEXT, &more) != DB_OK ) 
	{
	    CPLError( CE_Failure, CPLE_AppDefined, "Cannot fetch attributes.");
	    return false;
	}
	if ( !more ) break;

	dbColumn *column = db_get_table_column ( table, iCatField );
	dbValue *value = db_get_column_value ( column );
	int cat = db_get_value_int ( value );

	// NOTE: because of bug in GRASS library it is impossible to use
	//       Vect_cidx_find_next
	
	// Go through category index until first record of current category 
	// is found or a category > current is found
	int cidxcat, type, id;
	while ( cidx < ncats ) {
	    Vect_cidx_get_cat_by_index ( poMap, iLayerIndex, cidx, 
		                         &cidxcat, &type, &id );

	    if ( cidxcat < cat ) {
	    	cidx++;
		continue;
	    }
	    if ( cidxcat > cat ) break; // Not found
	    
	    // We have the category we want, check type
	    if ( !(type & (GV_POINT|GV_LINES|GV_AREA)) )
	    {
	    	cidx++;
		continue;
	    }

	    // Both category and type match -> find feature and set it on
	    while ( true ) {
		if ( fidx > nTotalCount || paFeatureIndex[fidx] > cidx ) { 
		    // should not happen
		    break;
		}
		    
		if ( paFeatureIndex[fidx] == cidx ) {
		    paQueryMatch[fidx] = 1;
		    fidx++;
		    break;
		}
		fidx++;
	    }
	    cidx++;
	}

	if ( id < 0 ) continue; // not found
    }

    return true;
}
    
/************************************************************************/
/*                           OpenSequentialCursor                       */
/************************************************************************/
bool OGRGRASSLayer::OpenSequentialCursor()
{
    CPLDebug ( "GRASS", "OpenSequentialCursor: %s", pszQuery  );

    if ( !poDriver ) 
    {
	CPLError( CE_Failure, CPLE_AppDefined, "Driver not opened.");
	return false;
    }