[libgda] Improved data model export

[Vivien Malerba <vivien src gnome org>]

commit 7b356dfe191598bfe6a7640bf8a6e6689c4371b5
Author: Vivien Malerba <malerba gnome-db org>
Date:   Wed Oct 27 18:50:55 2010 +0200

    Improved data model export
    
    uses a GdaDataModelIter iterator to export data
    which makes it possible to export data models which
    do not have a random access

 libgda/gda-data-model.c |   67 +++++++++++++++++++++++++++++++++--------------
 libgda/gda-util.c       |   43 +++++++++++++++++++++--------
 2 files changed, 78 insertions(+), 32 deletions(-)
---
diff --git a/libgda/gda-data-model.c b/libgda/gda-data-model.c
index b0bb221..14384c5 100644
--- a/libgda/gda-data-model.c
+++ b/libgda/gda-data-model.c
@@ -1013,6 +1013,11 @@ static gchar *export_to_text_separated (GdaDataModel *model, const gint *cols, g
  * gda_data_model_export_to_file() documentation for more information about the @options argument (except for the
  * "OVERWRITE" option).
  *
+ * Warning: this function uses a #GdaDataModelIter iterator, and if @model does not offer a random access
+ * (check using gda_data_model_get_access_flags()), the iterator will be the same as normally used
+ * to access data in @model previously to calling this method, and this iterator will be moved (point to
+ * another row).
+ *
  * Returns: a new string.
  */
 gchar *
@@ -1229,7 +1234,12 @@ gda_data_model_export_to_string (GdaDataModel *model, GdaDataModelIOFormat forma
  *   <listitem><para>"INVALID_AS_NULL": a boolean value which, if set to %TRUE, considers any invalid data (for example for the date related values) as NULL</para></listitem>
  * </itemizedlist>
  *
- * Upon errors FALSE will be returned and @error will be assigned a
+ * Warning: this function uses a #GdaDataModelIter iterator, and if @model does not offer a random access
+ * (check using gda_data_model_get_access_flags()), the iterator will be the same as normally used
+ * to access data in @model previously to calling this method, and this iterator will be moved (point to
+ * another row).
+ *
+ * Upon errors %FALSE will be returned and @error will be assigned a
  * #GError from the #GDA_DATA_MODEL_ERROR domain.
  *
  * Returns: TRUE if no error occurred
@@ -1237,8 +1247,8 @@ gda_data_model_export_to_string (GdaDataModel *model, GdaDataModelIOFormat forma
 gboolean
 gda_data_model_export_to_file (GdaDataModel *model, GdaDataModelIOFormat format, 
 			       const gchar *file,
-			       const gint *cols, G_GNUC_UNUSED gint nb_cols,
-			       const gint *rows, G_GNUC_UNUSED gint nb_rows,
+			       const gint *cols, gint nb_cols,
+			       const gint *rows, gint nb_rows,
 			       GdaSet *options, GError **error)
 {
 	gchar *body;
@@ -1248,7 +1258,7 @@ gda_data_model_export_to_file (GdaDataModel *model, GdaDataModelIOFormat format,
 	g_return_val_if_fail (!options || GDA_IS_SET (options), FALSE);
 	g_return_val_if_fail (file, FALSE);
 
-	body = gda_data_model_export_to_string (model, format, cols, nb_cols, rows, nb_cols, options);
+	body = gda_data_model_export_to_string (model, format, cols, nb_cols, rows, nb_rows, options);
 	if (options) {
 		GdaHolder *holder;
 		
@@ -1281,31 +1291,50 @@ gda_data_model_export_to_file (GdaDataModel *model, GdaDataModelIOFormat format,
 }
 
 static gchar *
-export_to_text_separated (GdaDataModel *model, const gint *cols, gint nb_cols, const gint *rows, gint nb_rows, 
-			  gchar sep, gchar quote, gboolean field_quotes, gboolean null_as_empty, gboolean invalid_as_null)
+export_to_text_separated (GdaDataModel *model, const gint *cols, gint nb_cols,
+			  const gint *rows, gint nb_rows, 
+			  gchar sep, gchar quote, gboolean field_quotes,
+			  gboolean null_as_empty, gboolean invalid_as_null)
 {
 	GString *str;
-	gchar *retval;
-	gint c, nbrows, r;
+	gint c;
+	GdaDataModelIter *iter;
+	gboolean addnl = FALSE;
 
 	g_return_val_if_fail (GDA_IS_DATA_MODEL (model), NULL);
 
 	str = g_string_new ("");
-	if (!rows)
-		nbrows = gda_data_model_get_n_rows (model);
-	else
-		nbrows = nb_rows;
+	iter = gda_data_model_create_iter (model);
+	if (!iter)
+		return g_string_free (str, FALSE);
 
-	for (r = 0; r < nbrows; r++) {
-		if (r > 0)
+	if ((gda_data_model_iter_get_row (iter) == -1) && ! gda_data_model_iter_move_next (iter)) {
+		g_object_unref (iter);
+		return g_string_free (str, FALSE);
+	}
+
+	for (; gda_data_model_iter_is_valid (iter); gda_data_model_iter_move_next (iter)) {
+		if (rows) {
+			gint r;
+			for (r = 0; r < nb_rows; r++) { 
+				if (gda_data_model_iter_get_row (iter) == rows[r])
+					break;
+			}
+			if (r == nb_rows)
+				continue;
+		}
+		
+		if (addnl)
 			str = g_string_append_c (str, '\n');
+		else
+			addnl = TRUE;
 
 		for (c = 0; c < nb_cols; c++) {
 			GValue *value;
 			gchar *txt;
 
-			value = (GValue *) gda_data_model_get_value_at (model, cols[c], rows ? rows[r] : r, NULL);
-			if (invalid_as_null) {
+			value = (GValue*) gda_data_model_iter_get_value_at (iter, cols[c]);
+			if (value && invalid_as_null) {
 				if ((G_VALUE_TYPE (value) == G_TYPE_DATE)) {
 					GDate *date = (GDate*) g_value_get_boxed (value);
 					if (!g_date_valid (date))
@@ -1357,10 +1386,8 @@ export_to_text_separated (GdaDataModel *model, const gint *cols, gint nb_cols, c
 		}
 	}
 
-	retval = str->str;
-	g_string_free (str, FALSE);
-
-	return retval;
+	g_object_unref (iter);
+	return g_string_free (str, FALSE);
 }
 
 static void
diff --git a/libgda/gda-util.c b/libgda/gda-util.c
index cfa3384..96024a8 100644
--- a/libgda/gda-util.c
+++ b/libgda/gda-util.c
@@ -34,6 +34,7 @@
 #include <libgda/gda-util.h>
 #include <libgda/gda-server-provider.h>
 #include <libgda/gda-column.h>
+#include <libgda/gda-data-model-iter.h>
 #ifdef HAVE_LOCALE_H
 #include <locale.h>
 #endif
@@ -331,6 +332,11 @@ gda_utility_check_data_model (GdaDataModel *model, gint nbcols, ...)
  *
  * Dump the data in a #GdaDataModel into a xmlNodePtr (as used in libxml).
  *
+ * Warning: this function uses a #GdaDataModelIter iterator, and if @model does not offer a random access
+ * (check using gda_data_model_get_access_flags()), the iterator will be the same as normally used
+ * to access data in @model previously to calling this method, and this iterator will be moved (point to
+ * another row).
+ *
  * Returns: TRUE if no error occurred
  */
 gboolean
@@ -340,13 +346,14 @@ gda_utility_data_model_dump_data_to_xml (GdaDataModel *model, xmlNodePtr parent,
 					 gboolean use_col_ids)
 {
 	gboolean retval = TRUE;
-	gint nrows, i;
 	gint *rcols, rnb_cols;
 	gchar **col_ids = NULL;
 	xmlNodePtr data = NULL;
+	GdaDataModelIter *iter;
 
 	/* compute columns if not provided */
 	if (!cols) {
+		gint i;
 		rnb_cols = gda_data_model_get_n_columns (model);
 		rcols = g_new (gint, rnb_cols);
 		for (i = 0; i < rnb_cols; i++)
@@ -377,23 +384,34 @@ gda_utility_data_model_dump_data_to_xml (GdaDataModel *model, xmlNodePtr parent,
 	}
 
 	/* add the model data to the XML output */
-	if (!rows)
-		nrows = gda_data_model_get_n_rows (model);
-	else
-		nrows = nb_rows;
-	if (nrows > 0) {
+	iter = gda_data_model_create_iter (model);
+	if (iter && (gda_data_model_iter_get_row (iter) == -1) && ! gda_data_model_iter_move_next (iter)) {
+		g_object_unref (iter);
+		iter = NULL;
+	}
+	if (iter) {
 		xmlNodePtr row;
-		gint r, c;
-
+		
 		data = xmlNewChild (parent, NULL, (xmlChar*)"gda_array_data", NULL);
-		for (r = 0; (r < nrows) && retval; r++) {
+		for (; retval && gda_data_model_iter_is_valid (iter); gda_data_model_iter_move_next (iter)) {
+			gint c;
+			if (rows) {
+				gint r;
+				for (r = 0; r < nb_rows; r++) { 
+					if (gda_data_model_iter_get_row (iter) == rows[r])
+						break;
+				}
+				if (r == nb_rows)
+					continue;
+			}
+
 			row = xmlNewChild (data, NULL,  (xmlChar*)"gda_array_row", NULL);
 			for (c = 0; c < rnb_cols; c++) {
 				GValue *value;
 				gchar *str = NULL;
 				xmlNodePtr field = NULL;
 
-				value = (GValue *) gda_data_model_get_value_at (model, rcols [c], rows ? rows [r] : r, NULL);
+				value = (GValue*) gda_data_model_iter_get_value_at (iter, rcols[c]);
 				if (!value) {
 					retval = FALSE;
 					break;
@@ -436,10 +454,11 @@ gda_utility_data_model_dump_data_to_xml (GdaDataModel *model, xmlNodePtr parent,
 				g_free (str);
 			}
 		}
+		g_object_unref (iter);
 	}
 
-	if(!cols)
-		g_free(rcols);
+	if (!cols)
+		g_free (rcols);
 
 	if (use_col_ids) {
 		gint c;