Experimenting with rjsmin in grit.

grit/format/data_pack.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Support for formatting a data pack file used for platform agnostic resource
 files.
 """
 
+import os
+import sys
+
+import rjsmin
+
 import collections
 import exceptions
 import os
 import struct
 import sys
 if __name__ == '__main__':
   sys.path.append(os.path.join(os.path.dirname(__file__), '../..'))
 
 from grit import util
 from grit.node import include
@@ skipping 16 matching lines @@
 
 
 def Format(root, lang='en', output_dir='.'):
   """Writes out the data pack file format (platform agnostic resource file)."""
   data = {}
   for node in root.ActiveDescendants():
     with node:
       if isinstance(node, (include.IncludeNode, message.MessageNode,
                            structure.StructureNode)):
         id, value = node.GetDataPackPair(lang, UTF8)
+        txt_id = node.GetTextualIds()[0]
+
+        # Use rjsmin to compress JavaScript resources. Closure would
+        # be even better but is tricky to integrate into the build
+        # system since it is Java.
+        if "_JS" in txt_id[-3:]:
+          size = len(value)
+          packed_value = rjsmin.jsmin(value)
+          packed_size = len(packed_value)
+          if packed_size < size:
+            value = packed_value
         if value is not None:
           data[id] = value
   return WriteDataPackToString(data, UTF8)
 
 
 def ReadDataPack(input_file):
   """Reads a data pack file and returns a dictionary."""
   data = util.ReadFile(input_file, util.BINARY)
   original_data = data
 
@@ skipping 147 matching lines @@
     # Just write a simple file.
     data = {1: '', 4: 'this is id 4', 6: 'this is id 6', 10: ''}
     WriteDataPack(data, 'datapack1.pak', UTF8)
     data2 = {1000: 'test', 5: 'five'}
     WriteDataPack(data2, 'datapack2.pak', UTF8)
     print 'wrote datapack1 and datapack2 to current directory.'
 
 
 if __name__ == '__main__':
   main()