py2exe fix to work with current pytz and better dist directory name

Review at http://codereview.appspot.com/9465
fix for issue 121: zoneinfo not included in py2exe library.zip
http://code.google.com/p/googletransitdatafeed/issues/detail?id=121

Author: Tom Brown

setup.py

@@ -49,6 +49,7 @@
   kwargs['data_files'] = \
       [('schedule_viewer_files',
           glob.glob(os.path.join('gtfsscheduleviewer', 'files', '*')))]
+  options['py2exe'] = {'dist_dir': 'transitfeed-windows-binary-%s' % VERSION}
 
 setup(
     version=VERSION,
@@ -87,3 +88,30 @@
     options=options,
     **kwargs
     )
+
+if has_py2exe:
+  # Sometime between pytz-2008a and pytz-2008i common_timezones started to
+  # include only names of zones with a corresponding data file in zoneinfo.
+  # pytz installs the zoneinfo directory tree in the same directory
+  # as the pytz/__init__.py file. These data files are loaded using
+  # pkg_resources.resource_stream. py2exe does not copy this to library.zip so
+  # resource_stream can't find the files and common_timezones is empty when
+  # read in the py2exe executable.
+  # This manually copies zoneinfo into the zip. See also
+  # http://code.google.com/p/googletransitdatafeed/issues/detail?id=121
+  import pytz
+  import zipfile
+  # Make sure the layout of pytz hasn't changed
+  assert (pytz.__file__.endswith('__init__.pyc') or
+          pytz.__file__.endswith('__init__.py')), pytz.__file__
+  zoneinfo_dir = os.path.join(os.path.dirname(pytz.__file__), 'zoneinfo')
+  # '..\\Lib\\pytz\\__init__.py' -> '..\\Lib'
+  disk_basedir = os.path.dirname(os.path.dirname(pytz.__file__))
+  zipfile_path = os.path.join(options['py2exe']['dist_dir'], 'library.zip')
+  z = zipfile.ZipFile(zipfile_path, 'a')
+  for absdir, directories, filenames in os.walk(zoneinfo_dir):
+    assert absdir.startswith(disk_basedir), (absdir, disk_basedir)
+    zip_dir = absdir[len(disk_basedir):]
+    for f in filenames:
+      z.write(os.path.join(absdir, f), os.path.join(zip_dir, f))
+  z.close()