Add the ability to specify a target_os for gclient solutions

This ability is useful for versions of Chromium (i.e. Android) which want to
cross-compile to another platform that has a fixed set of custom dependencies.

Review URL: http://codereview.chromium.org/10127004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@134280 0039d316-1c4b-4281-b951-d872f2087c98

gclient.py

@@ -47,6 +47,14 @@ Hooks
       { "pattern": "\\.(gif|jpe?g|pr0n|png)$",
         "action":  ["python", "image_indexer.py", "--all"]},
     ]
+
+Specifying a target OS
+  An optional key named "target_os" may be added to a gclient file to specify
+  one or more additional operating systems that should be considered when
+  processing the deps_os dict of a DEPS file.
+
+  Example:
+    target_os = [ "android" ]
 """
 
 __version__ = "0.6.4"
@@ -843,6 +851,10 @@ solutions = [
     except SyntaxError, e:
       gclient_utils.SyntaxErrorToError('.gclient', e)
 
+    # Append any target OS that is not already being enforced to the tuple.
+    target_os = config_dict.get('target_os', [])
+    self._enforced_os = tuple(set(self._enforced_os).union(target_os))
+
     deps_to_add = []
     for s in config_dict.get('solutions', []):
       try:

tests/gclient_test.py

@@ -275,6 +275,38 @@ class GclientTest(trial_dir.TestCase):
     work_queue.flush({}, None, [], options=options)
     self.assertEqual(client.GetHooks(options), [x['action'] for x in hooks])
 
+  def testTargetOS(self):
+    """Verifies that specifying a target_os pulls in all relevant dependencies.
+
+    The target_os variable allows specifying the name of an additional OS which
+    should be considered when selecting dependencies from a DEPS' deps_os. The
+    value will be appended to the _enforced_os tuple.
+    """
+
+    write(
+        '.gclient',
+        'solutions = [\n'
+        '  { "name": "foo",\n'
+        '    "url": "svn://example.com/foo",\n'
+        '  }]\n'
+        'target_os = ["baz"]')
+    write(
+        os.path.join('foo', 'DEPS'),
+        'deps = {\n'
+        '  "foo/dir1": "/dir1",'
+        '}\n'
+        'deps_os = {\n'
+        '  "unix": { "foo/dir2": "/dir2", },\n'
+        '  "baz": { "foo/dir3": "/dir3", },\n'
+        '}')
+
+    parser = gclient.Parser()
+    options, _ = parser.parse_args(['--jobs', '1'])
+    options.deps_os = "unix"
+
+    obj = gclient.GClient.LoadCurrentConfig(options)
+    self.assertEqual(['baz', 'unix'], sorted(obj.enforced_os))
+    
 
 if __name__ == '__main__':
   sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)