[PATCH] sort lots and entries on save

[Jim Radford]

The following patch sorts the lots and entries before saving them to
the gnucash XML file.

This is an attempt to make saves more idempotent thereby facilitating
the use of a revision control system on the gnucash XML files.

With this patch most of the needless and seemingly random churn is
gone and I can add and remove a transation and expect there to be no
changes to the gnucash file and I can add a transaction and expect
that addition to be the only change in the file.

I'm curious to see if this patch affects save performance noticeably
for anyone.  I don't have any large files to test with.

-Jim

diff -u gnucash-2.2.4/src/backend/file/gnc-account-xml-v2.c gnucash-2.2.4-sorted/src/backend/file/gnc-account-xml-v2.c
--- gnucash-2.2.4/src/backend/file/gnc-account-xml-v2.c	2008-03-02 05:24:27.000000000 -0800
+++ gnucash-2.2.4-sorted/src/backend/file/gnc-account-xml-v2.c	2008-04-23 15:06:13.000000000 -0700
@@ -139,6 +139,8 @@
     {
        xmlNodePtr toaddto = xmlNewChild(ret, NULL, BAD_CAST act_lots_string, NULL);
 
+       lots = g_list_sort(lots, qof_instance_guid_compare);
+
        for (n = lots; n; n=n->next)
        {
           GNCLot * lot = n->data;
--- gnucash-2.2.5/src/business/business-core/file/gnc-entry-xml-v2.c	2008-01-07 17:05:59.000000000 -0800
+++ gnucash-2.2.5/src/business/business-core/file/gnc-entry-xml-v2.c~	2008-07-01 17:41:19.000000000 -0700
@@ -814,9 +814,27 @@
 }
 
+static void
+do_append (QofInstance *qof_p, gpointer list_p)
+{
+  GList **list = list_p;
+  *list = g_list_append(*list, qof_p);
+}
+
+static void
+qof_object_foreach_sorted (QofIdTypeConst type_name, QofBook *book, QofInstanceForeachCB cb, gpointer user_data)
+{
+  GList *list = NULL, *n, *l;
+  qof_object_foreach(type_name, book, do_append, &list);
+  list = g_list_sort(list, qof_instance_guid_compare);
+  for (l = list; l; l = l->next)
+    cb(l->data, user_data);
+  g_list_free(list);
+}
+
 static void
 entry_write (FILE *out, QofBook *book)
 {
-  qof_object_foreach (_GNC_MOD_NAME, book, xml_add_entry, (gpointer) out);
+  qof_object_foreach_sorted (_GNC_MOD_NAME, book, xml_add_entry, (gpointer) out);
 }
 
 static void