Maris Nartiss: improved version with DB support

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32482 15284696-431f-4ddb-bdfa-cd5b030d7da7

doc/vector/v.example/main.c

@@ -2,27 +2,25 @@
  *
  * MODULE:     v.example
  *
- * AUTHOR(S):  GRASS Development Team
+ * AUTHOR(S):  GRASS Development Team, Radim Blazek, Maris Nartiss
  *
- * PURPOSE:    example vector module does something like:
- *               v.llabel -i map=m1 value=1
- *             but the new map is written instead of update of 
- *             the old one
+ * PURPOSE:    copies vector data from source map to destination map
+ *             prints out all point coordinates and atributes
  *
- * COPYRIGHT:  (C) 2002-2005 by the GRASS Development Team
+ * COPYRIGHT:  (C) 2002-2008 by the GRASS Development Team
  *
  *             This program is free software under the
  *             GNU General Public License (>=v2).
  *             Read the file COPYING that comes with GRASS
  *             for details.
  *
- * TODO:       - add DB support
  ****************************************************************/
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <grass/gis.h>
 #include <grass/Vect.h>
+#include <grass/dbmi.h>
 #include <grass/glocale.h>
 
 int main(int argc, char *argv[])
@@ -30,13 +28,21 @@ int main(int argc, char *argv[])
     struct Map_info In, Out;
     static struct line_pnts *Points;
     struct line_cats *Cats;
-    int i, type, cat;
-    char *mapset;
+    int i, type, cat, ncols, nrows, col, more, open3d;
+    char *mapset, sql[200];
     struct GModule *module;     /* GRASS module for parsing arguments */
     struct Option *old, *new;
+    dbDriver *driver;
+    dbHandle handle;
+    dbCursor cursor;
+    dbTable  *table;
+    dbColumn *column;
+    dbString table_name, dbsql, valstr;
+    struct field_info *Fi, *Fin;
 
     /* initialize GIS environment */
-    G_gisinit(argv[0]);		/* reads grass env, stores program name to G_program_name() */
+    /* reads grass env, stores program name to G_program_name() */
+    G_gisinit(argv[0]);
 
     /* initialize module */
     module = G_define_module();
@@ -50,44 +56,150 @@ int main(int argc, char *argv[])
 
     /* options and flags parser */
     if (G_parser(argc, argv))
-	exit(EXIT_FAILURE);
+		exit(EXIT_FAILURE);
 
+    /* Create and initialize struct's where to store points/lines and categories */
     Points = Vect_new_line_struct();
     Cats = Vect_new_cats_struct();
 
-    Vect_check_input_output_name(new->answer, old->answer, GV_FATAL_EXIT);
+	/* Check 1) output is legal vector name; 2) if can find input map; 
+		3) if input was found in current mapset, check if input != output.
+		lib/vector/Vlib/legal_vname.c
+	*/
+    Vect_check_input_output_name(old->answer, new->answer, GV_FATAL_EXIT);
 
     if ((mapset = G_find_vector2(old->answer, "")) == NULL)
-	G_fatal_error(_("Vector map <%s> not found"), old->answer);
+		G_fatal_error(_("Vector map <%s> not found"), old->answer);
 
-    Vect_set_open_level(2);
+    /* Predetermine level at which a map will be opened for reading 
+    	lib/vector/Vlib/open.c
+    */
+	if (Vect_set_open_level(2))
+		G_fatal_error(_("Unable to set predetermined vector open level"));
 
+    /* Open existing vector for reading
+    	lib/vector/Vlib/open.c
+    */
     if (1 > Vect_open_old(&In, old->answer, mapset))
-	G_fatal_error(_("Unable to open vector map <%s>"), old->answer);
-
-    if (0 > Vect_open_new(&Out, new->answer, WITHOUT_Z)) {
-	Vect_close(&In);
-	G_fatal_error(_("Unable to create vector map <%s>"), new->answer);
-    }
-
-    Vect_copy_head_data(&In, &Out);
-    Vect_hist_copy(&In, &Out);
-    Vect_hist_command(&Out);
-
-    i = 1;
-    while ((type = Vect_read_next_line(&In, Points, Cats)) > 0) {
-	if (type == GV_LINE) {
-	    if (Vect_cat_get(Cats, 1, &cat) == 0) {
-		Vect_cat_set(Cats, 1, i);
-		i++;
-	    }
+		G_fatal_error(_("Unable to open vector map <%s>"), old->answer);
+	
+	/* Check if old vector is 3D. We should preserve 3D data. */
+	if (Vect_is_3d(&In)) open3d = WITH_Z;
+	else open3d = WITHOUT_Z;
+	
+	/* Open new vector for reading/writing */
+	if (0 > Vect_open_new(&Out, new->answer, open3d)) {
+		Vect_close(&In);
+		G_fatal_error(_("Unable to create vector map <%s>"), new->answer);
 	}
-	Vect_write_line(&Out, type, Points, Cats);
-    }
 
+	/* Let's get vector layers db connections information */
+	Fi = Vect_get_field(&In, 1);
+	if (!Fi) {
+		Vect_close(&In);
+		G_fatal_error(_("Database connection not defined for layer %d"), 1);
+	}
+	/* Output information usefull for debuging 
+		incluse/vect/dig_structs.h
+	*/
+	G_debug(1,"Field number:%d; Name:<%s>; Driver:<%s>; Database:<%s>; Table:<%s>; Key:<%s>;\n",
+		Fi->number, Fi->name, Fi->driver, Fi->database, Fi->table, Fi->key);
+	
+	/* Prepeare strings for use in db_* calls */
+	db_init_string(&dbsql);
+	db_init_string(&valstr);
+	db_init_string(&table_name);
+	db_init_handle(&handle);
+	
+	/* Prepearing database for use */
+	driver = db_start_driver(Fi->driver);
+	if (driver == NULL) {
+		Vect_close(&In);
+		G_fatal_error(_("Unable to start driver <%s>"), Fi->driver);
+	}
+	db_set_handle(&handle, Fi->database, NULL);
+	if (db_open_database(driver, &handle) != DB_OK) {
+		Vect_close(&In);
+		G_fatal_error(_("Unable to open database <%s> by driver <%s>"), Fi->database, driver);
+	}
+	db_set_string(&table_name, Fi->table);
+	if (db_describe_table (driver, &table_name, &table) != DB_OK) {
+		Vect_close(&In);
+		G_fatal_error (_("Unable to describe table <%s>"), Fi->table);
+	}
+	ncols = db_get_table_number_of_columns(table);
+
+	/* Copy header and history data from old to new map */
+	Vect_copy_head_data(&In, &Out);
+	Vect_hist_copy(&In, &Out);
+	Vect_hist_command(&Out);
+
+	i = 1;
+	/* Let's do something with every vector feature in input map... */
+	/* Read in single line and get it's type */
+	while ((type = Vect_read_next_line(&In, Points, Cats)) > 0) {
+		/* If Points contain line... */
+		if (type == GV_LINE || type == GV_POINT || type == GV_CENTROID) {
+			if (Vect_cat_get(Cats, 1, &cat) == 0) {
+				Vect_cat_set(Cats, 1, i);
+				i++;
+			}
+		}
+		if (type == GV_POINT) {
+			/* Print out point coordinates */
+			printf("No:%d\tX:%f\tY:%f\tZ:%f\tCAT:%d\n",i,*Points->x,*Points->y,*Points->z,cat);
+			
+			/* Prepeare SQL query to get point atribute data */
+			sprintf(sql,"select * from %s where %s=%d",Fi->table,Fi->key,cat);
+			G_debug(1,"SQL: \"%s\"",sql);
+			db_set_string(&dbsql, sql);
+			/* Now execute query */
+			if (db_open_select_cursor(driver, &dbsql, &cursor, DB_SEQUENTIAL) != DB_OK)
+				G_warning(_("Unabale to get attribute data for cat %d"), cat);
+			else {
+				/* Result count */
+				nrows = db_get_num_rows(&cursor);
+				G_debug(1,"Result count: %d",nrows);
+				table = db_get_cursor_table (&cursor);
+				/* Let's output every columns name and value */
+				while(1) {
+					if (db_fetch (&cursor, DB_NEXT, &more) != DB_OK) {
+						G_warning(_("Error while retreiving database record for cat %d"), cat);
+						break;
+					}
+					if (!more) break;
+					for (col = 0; col < ncols; col++) {
+						column = db_get_table_column(table, col);
+						db_convert_column_value_to_string(column, &valstr);
+						printf("%s: %s\t", db_get_column_name(column), db_get_string(&valstr));
+					}
+					printf("\n");
+				}
+				db_close_cursor(&cursor);
+			}
+		}
+		/* Only now we write data into new vector */
+		Vect_write_line(&Out, type, Points, Cats);
+	}
+	
+	/* Create database for new vector map */
+	Fin = Vect_default_field_info(&Out, 1, NULL, GV_1TABLE);
+	driver = db_start_driver_open_database(Fin->driver, Fin->database);
+	G_debug(1,"Field number:%d; Name:<%s>; Driver:<%s>; Database:<%s>; Table:<%s>; Key:<%s>;\n",
+		Fin->number, Fin->name, Fin->driver, Fin->database, Fin->table, Fin->key);
+	
+	/* Let's copy atribute table data */
+	if (db_copy_table(Fi->driver,Fi->database,Fi->table,
+	Fin->driver,Vect_subst_var(Fin->database,&Out),Fin->table) == DB_FAILED)
+		G_warning(_("Unable to copy atribute table to vector map <%s>"), new->answer);
+	else Vect_map_add_dblink(&Out, Fin->number, Fin->name, Fin->table, Fi->key, Fin->database, Fin->driver);
+	
+    /* Build topology for vector map and close them */
     Vect_build(&Out, stdout);
     Vect_close(&In);
     Vect_close(&Out);
+    db_close_database_shutdown_driver(driver);
 
+	/* Don't forget to report to caller sucessfull end of data processing :) */
     exit(EXIT_SUCCESS);
 }