[libgda/metat: 5/9] gda-row: added model and model-row properties

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit d88c41036b4fa5f779e62878a8ffd22f0f476696
Author: Daniel Espinosa <esodan gmail com>
Date:   Mon Aug 20 14:37:24 2018 -0500

    gda-row: added  model and model-row properties
    
    This can be used to set a GdaDataModel and a row in it,
    to get data from.

 libgda/gda-row.c | 128 ++++++++++++++++++++++++++++++++++++++++++-------------
 libgda/gda-row.h |   1 +
 2 files changed, 99 insertions(+), 30 deletions(-)
---
diff --git a/libgda/gda-row.c b/libgda/gda-row.c
index 444254574..fa5233791 100644
--- a/libgda/gda-row.c
+++ b/libgda/gda-row.c
@@ -38,18 +38,20 @@
 #define PARENT_TYPE G_TYPE_OBJECT
 
 struct _GdaRowPrivate {
-       GdaDataModel *model; /* can be NULL */
+  GdaDataModel *model; /* can be NULL */
+  guint         model_row;
 
-        GValue       *fields; /* GValues */
-       GError      **errors; /* GError for each invalid value at the same position */
-        guint         nfields;
+  GValue       *fields; /* GValues */
+  GError      **errors; /* GError for each invalid value at the same position */
+  guint         nfields;
 };
 
 /* properties */
 enum
 {
-        PROP_0,
-        PROP_NB_VALUES
+  PROP_NB_VALUES = 1,
+  PROP_MODEL,
+  PROP_MODEL_ROW
 };
 
 static void gda_row_class_init (GdaRowClass *klass);
@@ -83,9 +85,19 @@ gda_row_class_init (GdaRowClass *klass)
         object_class->get_property = gda_row_get_property;
 
        g_object_class_install_property (object_class, PROP_NB_VALUES,
-                                         g_param_spec_int ("nb-values", NULL, "Number of values in the row",
+                                         g_param_spec_int ("nb-values", "NumValues", "Number of values in 
the row",
                                                           1, G_MAXINT, 1, 
-                                                          G_PARAM_WRITABLE));
+                                                          G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
+
+       g_object_class_install_property (object_class, PROP_MODEL,
+                                         g_param_spec_object ("model", "Model", "Data model used to get 
values from",
+                                                          GDA_TYPE_DATA_MODEL,
+                                                          G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
+
+       g_object_class_install_property (object_class, PROP_MODEL_ROW,
+                                         g_param_spec_int ("model-row", "ModelRow", "Row number in data 
model to get data from",
+                                                          0, G_MAXINT, 0,
+                                                          G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
 }
 
 static void
@@ -95,6 +107,7 @@ gda_row_init (GdaRow *row, G_GNUC_UNUSED GdaRowClass *klass)
        
        row->priv = g_new0 (GdaRowPrivate, 1);
        row->priv->model = NULL;
+  row->priv->model_row = 0;
        row->priv->fields = NULL;
        row->priv->errors = NULL;
        row->priv->nfields = 0;
@@ -118,17 +131,22 @@ gda_row_finalize (GObject *object)
        g_return_if_fail (GDA_IS_ROW (row));
        
        if (row->priv) {
-               guint i;
-
-               for (i = 0; i < row->priv->nfields; i++) {
-                       gda_value_set_null (&(row->priv->fields [i]));
-                       if (row->priv->errors && row->priv->errors [i])
-                               g_error_free (row->priv->errors [i]);
-               }
-               g_free (row->priv->fields);
-               g_free (row->priv->errors);
-
-               g_free (row->priv);
+    if (row->priv->model == NULL) {
+                 guint i;
+
+                 for (i = 0; i < row->priv->nfields; i++) {
+                         gda_value_set_null (&(row->priv->fields [i]));
+                         if (row->priv->errors && row->priv->errors [i])
+                                 g_error_free (row->priv->errors [i]);
+                 }
+                 g_free (row->priv->fields);
+                 g_free (row->priv->errors);
+
+                 g_free (row->priv);
+    } else {
+      g_object_unref (row->priv->model);
+      row->priv->model = NULL;
+    }
                row->priv = NULL;
        }
        
@@ -146,7 +164,11 @@ gda_row_set_property (GObject *object,
         row = GDA_ROW (object);
         if (row->priv) {
                 switch (param_id) {
-               case PROP_NB_VALUES: {
+               case PROP_NB_VALUES:
+      if (row->priv->model != NULL) {
+        g_warning (_("Can't set a number of values, because a data model is in use"));
+        break;
+      }
                        guint i;
                        g_return_if_fail (!row->priv->fields);
 
@@ -155,7 +177,18 @@ gda_row_set_property (GObject *object,
                        for (i = 0; i < row->priv->nfields; i++)
                                gda_value_set_null (& (row->priv->fields [i]));
                        break;
-               }
+    case PROP_MODEL:
+      if (row->priv->nfields != 0) {
+        break;
+      }
+      row->priv->model = GDA_DATA_MODEL(g_object_ref (g_value_get_object (value)));
+      break;
+    case PROP_MODEL_ROW:
+      if (row->priv->nfields != 0) {
+        break;
+      }
+      row->priv->model_row = g_value_get_uint (value);
+      break;
                default:
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, param_id, pspec);
                        break;
@@ -177,6 +210,12 @@ gda_row_get_property (GObject *object,
                case PROP_NB_VALUES:
                        g_value_set_int (value, row->priv->nfields);
                        break;
+               case PROP_MODEL:
+                       g_value_set_object (value, row->priv->model);
+                       break;
+               case PROP_MODEL_ROW:
+                       g_value_set_uint (value, row->priv->model_row);
+                       break;
                default:
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, param_id, pspec);
                        break;
@@ -228,6 +267,23 @@ gda_row_new (gint count)
        return (GdaRow*) g_object_new (GDA_TYPE_ROW, "nb-values", count, NULL);
 }
 
+/**
+ * gda_row_new_from_data_model:
+ * @model: a #GdaDataModel to get data from.
+ * @row: row at #GdaDataModel to get data from
+ *
+ * Creates a #GdaRow which represent a row in a #GdaDataModel
+ *
+ * Returns: (transfer full):a newly allocated #GdaRow object.
+ */
+GdaRow *
+gda_row_new_from_data_model (GdaDataModel *model, guint row)
+{
+  g_return_val_if_fail (model, NULL);
+  g_return_val_if_fail (GDA_IS_DATA_MODEL (model), NULL);
+       return (GdaRow*) g_object_new (GDA_TYPE_ROW, "model", model, "model-row", row, NULL);
+}
+
 /**
  * gda_row_get_value:
  * @row: a #GdaRow
@@ -238,15 +294,26 @@ gda_row_new (gint count)
  * This is a pointer to the internal array of values. Don't try to free
  * or modify it (modifying is reserved to database provider's implementations).
  *
- * Returns: (allow-none) (transfer none): a pointer to the #GValue in the position @num of @row.
+ * Returns: (nullable) (transfer none): a pointer to the #GValue in the position @num of @row.
  */
 GValue *
 gda_row_get_value (GdaRow *row, gint num)
 {
-        g_return_val_if_fail (GDA_IS_ROW (row), NULL);
-        g_return_val_if_fail ((num >= 0) && ((guint) num < row->priv->nfields), NULL);
-
-        return & (row->priv->fields[num]);
+  g_return_val_if_fail (GDA_IS_ROW (row), NULL);
+  if (row->priv->model == NULL) {
+    g_return_val_if_fail ((num >= 0) && ((guint) num < row->priv->nfields), NULL);
+    return & (row->priv->fields[num]);
+  } else {
+    GError *error = NULL;
+    const GValue *value = NULL;
+    g_return_val_if_fail ((num >= 0) && (num < gda_data_model_get_n_columns (row->priv->model)), NULL);
+    value = gda_data_model_get_value_at (row->priv->model, num, row->priv->model_row, &error);
+    if (value == NULL) {
+      g_warning (_("No value can be retrieved from data model's row: %s"),
+                 error ? (error->message ? error->message : _("No Detail")) : _("No error was set"));
+    }
+  }
+  return NULL;
 }
 
 /**
@@ -372,8 +439,9 @@ gda_row_value_is_valid_e (GdaRow *row, GValue *value, GError **error)
 gint
 gda_row_get_length (GdaRow *row)
 {
-        g_return_val_if_fail (GDA_IS_ROW (row), 0);
-       g_return_val_if_fail (row->priv, 0);
-
-        return row->priv->nfields;
+  g_return_val_if_fail (GDA_IS_ROW (row), 0);
+  g_return_val_if_fail (row->priv, 0);
+  if (row->priv->model == NULL)
+    return row->priv->nfields;
+  return gda_data_model_get_n_columns (row->priv->model);
 }
diff --git a/libgda/gda-row.h b/libgda/gda-row.h
index 992864d90..4d9f14d10 100644
--- a/libgda/gda-row.h
+++ b/libgda/gda-row.h
@@ -75,6 +75,7 @@ struct _GdaRowClass {
 GType         gda_row_get_type       (void) G_GNUC_CONST;
 
 GdaRow       *gda_row_new            (gint count);
+GdaRow       *gda_row_new_from_data_model (GdaDataModel *model, guint row);
 gint          gda_row_get_length     (GdaRow *row);
 GValue       *gda_row_get_value      (GdaRow *row, gint num);