Bug 639322 part 1: add extension .gcm to future state files

Old state files are still read (if no new equivalent exists yet)
but will never be written to again.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@20098 57a11ea4-9604-0410-9ed3-97b8803252fd

src/app-utils/file-utils.c

@@ -177,18 +177,30 @@ gnc_getline (gchar **line, FILE *file)
     return len;
 }
 
-/*  Find the state file that corresponds to this URL and guid.  The
- *  URL is used to compute the base name of the file (which will be in
- *  ~/.gnucash/books) and the guid is used to differentiate when the
- *  user has multiple data files with the same name. */
+/*  Find the state file that corresponds to this URL and guid.
+ *
+ * The state files will be searched for in the books directory in GnuCash'
+ * private configuration directory. This configuration directory is
+ * platform dependent and can be overridden with environment variable
+ * DOT_GNUCASH_DIR. On linux for example this is ~/.gnucash by default.
+ *
+ * The URL is used to compute the base name of the state file and the
+ * guid is used to differentiate when the user has multiple data files
+ * with the same name.
+ *
+ * As of GnuCash 2.4.1 state files will have their own extension to
+ * differentiate them from data files saved by the user. New state
+ * files will always be created with such an extension. But GnuCash
+ * will continue to search for state files without an extension if
+ * no proper state file with extension is found. */
 GKeyFile *
 gnc_find_state_file (const gchar *url,
                      const gchar *guid,
                      gchar **filename_p)
 {
     gchar *basename, *original = NULL, *filename, *tmp, *file_guid;
+    gchar *sf_extension = NULL, *newstyle_filename = NULL;
     GKeyFile *key_file = NULL;
-    gboolean do_increment = FALSE;
     gint i;
 
     ENTER("url %s, guid %s", url, guid);
@@ -225,13 +237,14 @@ gnc_find_state_file (const gchar *url,
     g_free(basename);
     DEBUG("Original %s", original);
 
+    sf_extension = g_strdup(STATE_FILE_EXT);
     i = 1;
     while (1)
     {
         if (i == 1)
-            filename = g_strdup(original);
+            filename = g_strconcat(original, sf_extension, NULL);
         else
-            filename = g_strdup_printf("%s_%d", original, i);
+            filename = g_strdup_printf("%s_%d%s", original, i, sf_extension);
         DEBUG("Trying %s", filename);
         key_file = gnc_key_file_load_from_file(filename, FALSE, FALSE, NULL);
         DEBUG("Result %p", key_file);
@@ -239,6 +252,15 @@ gnc_find_state_file (const gchar *url,
         if (!key_file)
         {
             DEBUG("No key file by that name");
+            if (g_strcmp0(sf_extension, STATE_FILE_EXT) == 0)
+            {
+                DEBUG("Trying old state file names for compatibility");
+                newstyle_filename = filename;
+                i = 1;
+                g_free( sf_extension);
+                sf_extension = g_strdup("");
+                continue;
+            }
             break;
         }
 
@@ -252,22 +274,25 @@ gnc_find_state_file (const gchar *url,
             g_free(file_guid);
             break;
         }
-        else
-        {
-            do_increment = TRUE;
-        }
-
-
         DEBUG("Clean up this pass");
         g_free(file_guid);
         g_key_file_free(key_file);
         g_free(filename);
-        if (do_increment)
-            i++;
+        i++;
     }
 
     DEBUG("Clean up");
     g_free(original);
+    /* Pre-2.4.1 compatibility block: make sure when the state file is
+     * written again later, it will use the next available filename with
+     * extension and optional counter. (This name was determined earlier
+     * in the loop.) */
+    if (newstyle_filename)
+    {
+        g_free(filename);
+        filename = newstyle_filename;
+    }
+
     if (filename_p)
         *filename_p = filename;
     else

src/app-utils/file-utils.h

@@ -95,6 +95,7 @@ gint64 gnc_getline (gchar **line, FILE *file);
 /* Definitions shared by file-utils.c and gnc-main-window.c */
 #define STATE_FILE_TOP           "Top"
 #define STATE_FILE_BOOK_GUID     "BookGuid"
+#define STATE_FILE_EXT           ".gcm"
 
 /** Find the state file that corresponds to this URL and guid.
  *