[libgda] Added checks in GdaDataModelIter and improved doc.

[Vivien Malerba <vivien src gnome org>]

commit 1e85e358b1ff4625056aad82b3cde864e4b55d39
Author: Vivien Malerba <malerba gnome-db org>
Date:   Sat Apr 9 15:05:39 2011 +0200

    Added checks in GdaDataModelIter and improved doc.

 libgda/gda-data-model-iter.c |   11 +++++++----
 libgda/gda-data-model-iter.h |    4 ++++
 libgda/gda-data-model.c      |    7 ++++---
 3 files changed, 15 insertions(+), 7 deletions(-)
---
diff --git a/libgda/gda-data-model-iter.c b/libgda/gda-data-model-iter.c
index bf01102..9c420bc 100644
--- a/libgda/gda-data-model-iter.c
+++ b/libgda/gda-data-model-iter.c
@@ -1,6 +1,5 @@
-/* gda-data-model-iter.c
- *
- * Copyright (C) 2005 - 2010 Vivien Malerba
+/*
+ * Copyright (C) 2005 - 2011 Vivien Malerba
  *
  * This Library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public License as
@@ -84,7 +83,7 @@ enum
 /* private structure */
 struct _GdaDataModelIterPrivate
 {
-	GdaDataModel          *data_model;
+	GdaDataModel          *data_model; /* may be %NULL because there is only a weak ref on it */
 	gulong                 model_changes_signals[3];
 	gboolean               keep_param_changes;
 	gint                   row; /* -1 if row is unknown */
@@ -621,6 +620,8 @@ gda_data_model_iter_move_to_row (GdaDataModelIter *iter, gint row)
 
 		gboolean move_ok;
 		model = iter->priv->data_model;
+		g_return_val_if_fail (iter->priv->data_model, FALSE);
+
 		if (GDA_DATA_MODEL_GET_CLASS (model)->i_iter_at_row)
 			move_ok = (GDA_DATA_MODEL_GET_CLASS (model)->i_iter_at_row) (model, iter, row);
 		else {
@@ -726,6 +727,7 @@ gda_data_model_iter_move_next (GdaDataModelIter *iter)
 	GdaDataModel *model;
 	g_return_val_if_fail (GDA_IS_DATA_MODEL_ITER (iter), FALSE);
 	g_return_val_if_fail (iter->priv, FALSE);
+	g_return_val_if_fail (iter->priv->data_model, FALSE);
 
 	if ((gda_data_model_iter_get_row (iter) >= 0) &&
 	    ! _gda_set_validate ((GdaSet*) iter, NULL))
@@ -814,6 +816,7 @@ gda_data_model_iter_move_prev (GdaDataModelIter *iter)
 
 	g_return_val_if_fail (GDA_IS_DATA_MODEL_ITER (iter), FALSE);
 	g_return_val_if_fail (iter->priv, FALSE);
+	g_return_val_if_fail (iter->priv->data_model, FALSE);
 
 	if ((gda_data_model_iter_get_row (iter) >= 0) &&
 	    ! _gda_set_validate ((GdaSet*) iter, NULL))
diff --git a/libgda/gda-data-model-iter.h b/libgda/gda-data-model-iter.h
index dfae94d..a12ec98 100644
--- a/libgda/gda-data-model-iter.h
+++ b/libgda/gda-data-model-iter.h
@@ -107,6 +107,10 @@ struct _GdaDataModelIterClass
  *     <phrase>GdaDataModelIter's usage</phrase>
  *   </textobject>
  * </mediaobject>
+ *
+ * Note: the new #GdaDataModelIter does not hold any reference to the data model it iterates through (ie.
+ * if this data model is destroyed at some point, the new iterator will become useless but in
+ * any case it will not prevent the data model from being destroyed).
  */
 
 GType             gda_data_model_iter_get_type             (void) G_GNUC_CONST;
diff --git a/libgda/gda-data-model.c b/libgda/gda-data-model.c
index 976013b..a4a8731 100644
--- a/libgda/gda-data-model.c
+++ b/libgda/gda-data-model.c
@@ -1,6 +1,5 @@
 /* 
- * GDA common library
- * Copyright (C) 1998 - 2010 The GNOME Foundation.
+ * Copyright (C) 1998 - 2011 The GNOME Foundation.
  *
  * AUTHORS:
  *	Rodrigo Moya <rodrigo gnome-db org>
@@ -772,7 +771,9 @@ gda_data_model_set_values (GdaDataModel *model, gint row, GList *values, GError
  * @model: a #GdaDataModel object.
  *
  * Creates a new iterator object #GdaDataModelIter object which can be used to iterate through
- * rows in @model.
+ * rows in @model. The new #GdaDataModelIter does not hold any reference to @model (ie. if @model
+ * is destroyed at some point, the new iterator will become useless but in any case it will not prevent
+ * the data model from being destroyed).
  *
  * Depending on the data model's implementation, a new #GdaDataModelIter object may be created,
  * or a reference to an already existing #GdaDataModelIter may be returned.