Bug 797165 - Crash on price deletion.

Caused by the introduction of caching used in gnc_pricedb_nth_price,
when prices were deleted, the cached list was never updated and so the
tree model could reference a deleted price and hence crash. This also
affected adding prices as the new prices would not show due to the
cache not being updated. To fix this a function was added to reset the
cache when prices are updated from the model.

gnucash/gnome-utils/gnc-tree-model-price.c

@@ -1474,7 +1474,7 @@ gnc_tree_model_price_row_delete (GncTreeModelPrice *model,
  *  item removal.
  */
 static gboolean
-gnc_tree_model_price_do_deletions (gpointer unused)
+gnc_tree_model_price_do_deletions (gpointer price_db)
 {
     ENTER(" ");
 
@@ -1490,6 +1490,7 @@ gnc_tree_model_price_do_deletions (gpointer unused)
 
             /* Remove the path. */
             gnc_tree_model_price_row_delete(data->model, data->path);
+            gnc_pricedb_nth_price_reset_cache (price_db);
 
             gtk_tree_path_free(data->path);
             g_free(data);
@@ -1540,6 +1541,7 @@ gnc_tree_model_price_event_handler (QofInstance *entity,
                                     gpointer event_data)
 {
     GncTreeModelPrice *model;
+    GncTreeModelPricePrivate *priv;
     GtkTreePath *path;
     GtkTreeIter iter;
     remove_data *data;
@@ -1548,10 +1550,11 @@ gnc_tree_model_price_event_handler (QofInstance *entity,
     ENTER("entity %p, event %d, model %p, event data %p",
           entity, event_type, user_data, event_data);
     model = (GncTreeModelPrice *)user_data;
+    priv = GNC_TREE_MODEL_PRICE_GET_PRIVATE(model);
 
     /* Do deletions if any are pending. */
     if (pending_removals)
-        gnc_tree_model_price_do_deletions(NULL);
+        gnc_tree_model_price_do_deletions (priv->price_db);
 
     /* hard failures */
     g_return_if_fail(GNC_IS_TREE_MODEL_PRICE(model));
@@ -1611,8 +1614,9 @@ gnc_tree_model_price_event_handler (QofInstance *entity,
     switch (event_type)
     {
     case QOF_EVENT_ADD:
-        /* Tell the filters/views where the new account was added. */
+        /* Tell the filters/views where the new price was added. */
         DEBUG("add %s", name);
+        gnc_pricedb_nth_price_reset_cache (priv->price_db);
         gnc_tree_model_price_row_add (model, &iter);
         break;
 
@@ -1631,7 +1635,7 @@ gnc_tree_model_price_event_handler (QofInstance *entity,
         data->path = path;
         pending_removals = g_slist_append (pending_removals, data);
         g_idle_add_full(G_PRIORITY_HIGH_IDLE,
-                        gnc_tree_model_price_do_deletions, NULL, NULL);
+                        gnc_tree_model_price_do_deletions, priv->price_db, NULL);
 
         LEAVE(" ");
         return;

libgnucash/engine/gnc-pricedb-p.h

@@ -57,6 +57,7 @@ struct gnc_price_db_s
     QofInstance inst;              /* globally unique object identifier */
     GHashTable *commodity_hash;
     gboolean bulk_update;		 /* TRUE while reading XML file, etc. */
+    gboolean reset_nth_price_cache;
 };
 
 struct _GncPriceDBClass

libgnucash/engine/gnc-pricedb.c

@@ -839,6 +839,7 @@ QOF_GOBJECT_IMPL(gnc_pricedb, GNCPriceDB, QOF_TYPE_INSTANCE);
 static void
 gnc_pricedb_init(GNCPriceDB* pdb)
 {
+    pdb->reset_nth_price_cache = FALSE;
 }
 
 static void
@@ -2202,7 +2203,7 @@ gnc_pricedb_nth_price (GNCPriceDB *db,
     if (!db || !c || n < 0) return NULL;
     ENTER ("db=%p commodity=%s index=%d", db, gnc_commodity_get_mnemonic(c), n);
 
-    if (last_c && prices && last_c == c)
+    if (last_c && prices && last_c == c && db->reset_nth_price_cache == FALSE)
     {
         result = g_list_nth_data (prices, n);
         LEAVE ("price=%p", result);
@@ -2217,6 +2218,8 @@ gnc_pricedb_nth_price (GNCPriceDB *db,
         prices = NULL;
     }
 
+    db->reset_nth_price_cache = FALSE;
+
     currency_hash = g_hash_table_lookup (db->commodity_hash, c);
     if (currency_hash)
     {
@@ -2230,6 +2233,13 @@ gnc_pricedb_nth_price (GNCPriceDB *db,
     return result;
 }
 
+void
+gnc_pricedb_nth_price_reset_cache (GNCPriceDB *db)
+{
+    if (db)
+        db->reset_nth_price_cache = TRUE;
+}
+
 GNCPrice *
 gnc_pricedb_lookup_day_t64(GNCPriceDB *db,
                            const gnc_commodity *c,

libgnucash/engine/gnc-pricedb.h

@@ -633,6 +633,8 @@ gnc_pricedb_nth_price (GNCPriceDB *db,
                        const gnc_commodity *c,
                        const int n);
 
+void gnc_pricedb_nth_price_reset_cache (GNCPriceDB *db);
+
 /* The following two convenience functions are used to test the xml backend */
 /** @brief Return the number of prices in the database.
  *