Add package_framework.py from the Chromium buildroot to setup Mac fra…

…mework symlinks. (flutter#111)

build/config/mac/package_framework.py

@@ -0,0 +1,60 @@
+# Copyright 2016 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.
+
+import argparse
+import errno
+import os
+import shutil
+import sys
+
+def Main():
+  parser = argparse.ArgumentParser(description='Create Mac Framework symlinks')
+  parser.add_argument('--framework', action='store', type=str, required=True)
+  parser.add_argument('--version', action='store', type=str)
+  parser.add_argument('--contents', action='store', type=str, nargs='+')
+  parser.add_argument('--stamp', action='store', type=str, required=True)
+  args = parser.parse_args()
+
+  VERSIONS = 'Versions'
+  CURRENT = 'Current'
+
+  # Ensure the Foo.framework/Versions/A/ directory exists and create the
+  # Foo.framework/Versions/Current symlink to it.
+  if args.version:
+    try:
+      os.makedirs(os.path.join(args.framework, VERSIONS, args.version), 0744)
+    except OSError as e:
+      if e.errno != errno.EEXIST:
+        raise e
+    _Relink(os.path.join(args.version),
+            os.path.join(args.framework, VERSIONS, CURRENT))
+
+  # Establish the top-level symlinks in the framework bundle. The dest of
+  # the symlinks may not exist yet.
+  if args.contents:
+    for item in args.contents:
+      _Relink(os.path.join(VERSIONS, CURRENT, item),
+              os.path.join(args.framework, item))
+
+  # Write out a stamp file.
+  if args.stamp:
+    with open(args.stamp, 'w') as f:
+      f.write(str(args))
+
+  return 0
+
+
+def _Relink(dest, link):
+  """Creates a symlink to |dest| named |link|. If |link| already exists,
+  it is overwritten."""
+  try:
+    os.remove(link)
+  except OSError as e:
+    if e.errno != errno.ENOENT:
+      shutil.rmtree(link)
+  os.symlink(dest, link)
+
+
+if __name__ == '__main__':
+  sys.exit(Main())