core: Add checksum builtin

This necessitated reworking things so that builtins can specify no
--repo is required.

src/ostree/ot-builtin-checksum.c

@@ -0,0 +1,70 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2011 Colin Walters <walters@verbum.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Author: Colin Walters <walters@verbum.org>
+ */
+
+#include "config.h"
+
+#include "ot-builtins.h"
+#include "ostree.h"
+
+#include <glib/gi18n.h>
+
+static GOptionEntry options[] = {
+  { NULL }
+};
+
+gboolean
+ostree_builtin_checksum (int argc, char **argv, const char *repo_path, GError **error)
+{
+  GOptionContext *context;
+  gboolean ret = FALSE;
+  GChecksum *checksum = NULL;
+  GFile *f = NULL;
+
+  context = g_option_context_new ("FILENAME - Checksum a file or directory");
+  g_option_context_add_main_entries (context, options, NULL);
+
+  if (!g_option_context_parse (context, &argc, &argv, error))
+    goto out;
+
+  if (argc > 1)
+    f = ot_util_new_file_for_path (argv[1]);
+  else
+    {
+      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                           "A filename must be given");
+      goto out;
+    }
+
+  if (!ostree_checksum_file (f, OSTREE_OBJECT_TYPE_FILE, &checksum, NULL, error))
+    goto out;
+
+  g_print ("%s\n", g_checksum_get_string (checksum));
+ 
+  ret = TRUE;
+ out:
+  if (checksum)
+    g_checksum_free (checksum);
+  g_clear_object (&f);
+  if (context)
+    g_option_context_free (context);
+  return ret;
+}