check_dups: Add a script to check for the same resource in multiple pak files.

grit/format/check_dups.py

Index: grit/format/check_dups.py
diff --git a/grit/format/check_dups.py b/grit/format/check_dups.py
new file mode 100644
index 0000000000000000000000000000000000000000..0ecc0b4af2217630d4984bab8e75f092d67e7d46
--- /dev/null
+++ b/grit/format/check_dups.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Check for duplicate resource in multiple pack files."""
+
+import os
+import sys
+
+if __name__ == '__main__':
+  sys.path.append(os.path.join(os.path.dirname(__file__), '../..'))
+
+from grit.format.data_pack import DataPack
+
+class ResourceDuplicateException(Exception):
+  pass
+
+
+def CheckDupResource(resource_filenames):
+  resources = {}
+  for filename in resource_filenames:
+    pack = DataPack.ReadDataPack(filename)
+    for (resource_id, data) in pack.resources.iteritems():
+      if resource_id in resources:
+        details = resources[resource_id]
+        raise ResourceDuplicateException(
+            "Duplicate resource with id %s in %s (size %d) and %s (size %d)" %
+            (resource_id, details['filename'],
+             details['size'], filename, len(data)))
+      resources[resource_id] = {
+        'filename': filename,
+        'size': len(data)
+      }
+
+
+def main():
+  if len(sys.argv) < 2:
+    print "There must be at least two pak files as input."
+    return
+  CheckDupResource(sys.argv[1:])
+
+
+if __name__ == '__main__':
+  main()