Use the lowest MacOS SDK available on a system

tools/gyp/find_mac_sdk.py

Index: tools/gyp/find_mac_sdk.py
diff --git a/tools/gyp/find_mac_sdk.py b/tools/gyp/find_mac_sdk.py
new file mode 100755
index 0000000000000000000000000000000000000000..baf627981e6ab59df8ab8dbfad6f0f0c8894f063
--- /dev/null
+++ b/tools/gyp/find_mac_sdk.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.

[ahe, 2013/03/20 10:50:03]

Something fishy with the copyrights in this file.

[kustermann, 2013/03/21 08:43:00]

Well, as you can see on line 10 this file was copied from the chromium
repository. Ricow told me I should look into 'runtime/bin/net/nss.gyp' (because
that was copied as well) -- so I just followed that style of having two
copyright notices.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+# This file is a copy of Chromium's src/build/mac/find_sdk.py.
+# Revision 180337.
+
+import os
+import re
+import subprocess
+import sys
+
+"""Prints the lowest locally available SDK version greater than or equal to a
+given minimum sdk version to standard output.
+
+Usage:
+  python find_sdk.py 10.6  # Ignores SDKs < 10.6
+"""
+
+from optparse import OptionParser
+
+
+def parse_version(version_str):
+  """'10.6' => [10, 6]"""
+  return map(int, re.findall(r'(\d+)', version_str))
+
+
+def main():
+  parser = OptionParser()
+  parser.add_option("--verify",
+                    action="store_true", dest="verify", default=False,
+                    help="return the sdk argument and warn if it doesn't exist")
+  parser.add_option("--sdk_path",
+                    action="store", type="string", dest="sdk_path", default="",
+                    help="user-specified SDK path; bypasses verification")
+  (options, args) = parser.parse_args()
+  min_sdk_version = args[0]
+
+  job = subprocess.Popen(['xcode-select', '-print-path'],
+                         stdout=subprocess.PIPE,
+                         stderr=subprocess.STDOUT)
+  out, err = job.communicate()
+  if job.returncode != 0:
+    print >>sys.stderr, out
+    print >>sys.stderr, err
+    raise Exception(('Error %d running xcode-select, you might have to run '
+      '|sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer| '
+      'if you are using Xcode 4.') % job.returncode)
+  # The Developer folder moved in Xcode 4.3.
+  xcode43_sdk_path = os.path.join(
+      out.rstrip(), 'Platforms/MacOSX.platform/Developer/SDKs')
+  if os.path.isdir(xcode43_sdk_path):
+    sdk_dir = xcode43_sdk_path
+  else:
+    sdk_dir = os.path.join(out.rstrip(), 'SDKs')
+  sdks = [re.findall('^MacOSX(10\.\d+)\.sdk$', s) for s in os.listdir(sdk_dir)]
+  sdks = [s[0] for s in sdks if s]  # [['10.5'], ['10.6']] => ['10.5', '10.6']
+  sdks = [s for s in sdks  # ['10.5', '10.6'] => ['10.6']
+          if parse_version(s) >= parse_version(min_sdk_version)]
+  if not sdks:
+    raise Exception('No %s+ SDK found' % min_sdk_version)
+  best_sdk = sorted(sdks, key=parse_version)[0]
+
+  if options.verify and best_sdk != min_sdk_version and not options.sdk_path:
+    print >>sys.stderr, ''
+    print >>sys.stderr, '                                           vvvvvvv'
+    print >>sys.stderr, ''
+    print >>sys.stderr, \
+        'This build requires the %s SDK, but it was not found on your system.' \
+        % min_sdk_version
+    print >>sys.stderr, \
+        'Either install it, or explicitly set mac_sdk in your GYP_DEFINES.'
+    print >>sys.stderr, ''
+    print >>sys.stderr, '                                           ^^^^^^^'
+    print >>sys.stderr, ''
+    return min_sdk_version
+
+  return best_sdk
+
+
+if __name__ == '__main__':
+  if sys.platform != 'darwin':
+    raise Exception("This script only runs on Mac")
+  print main()