Make MB aware of iOS bot configs and get iOS working.

tools/mb/mb.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 """MB - the Meta-Build wrapper around GYP and GN
 
 MB is a wrapper script for GYP and GN that can be used to generate build files
 for sets of canned configurations and analyze them.
 """
@@ skipping 337 matching lines @@
     config = self.ConfigFromArgs()
     if not config in self.configs:
       raise MBErr('Config "%s" not found in %s' %
                   (config, self.args.config_file))
 
     vals = self.FlattenConfig(config)
 
     # Do some basic sanity checking on the config so that we
     # don't have to do this in every caller.
     assert 'type' in vals, 'No meta-build type specified in the config'
-    assert vals['type'] in ('gn', 'gyp'), (
+    assert vals['type'] in ('gn', 'gyp', 'passthrough'), (
         'Unknown meta-build type "%s"' % vals['gn_args'])
 
+    if vals['type'] == 'passthrough':
+      vals = self.HandlePassthrough()
+
+    return vals
+
+  def HandlePassthrough(self):
+    if 'MB_TYPE' not in os.environ:
+      raise MBErr('MB_TYPE not set in the environment')
+    mb_type = os.environ['MB_TYPE']
+    if mb_type not in ('gyp', 'gn'):
+      raise MBErr('illegal value "%s" for MB_TYPE', mb_type)
+
+    vals = self.DefaultConfigVals()
+    vals['type'] = mb_type
+    if mb_type == 'gyp':
+      if 'GYP_CROSSCOMPILE' in os.environ:
+        if os.environ['GYP_CROSSCOMPILE'] == '1':
+          vals['gyp_crosscompile'] = True
+      if 'GYP_DEFINES' not in os.environ:
+        raise MBErr('GYP_DEFINES not set in environment on a '
+                    'passthrough bot set to type GYP.')
+      vals['gyp_defines'] = os.environ['GYP_DEFINES']
+    else:
+      if 'gn_args' not in os.environ:
+        raise MBErr('GN_ARGS not set in environment on a passthrough bot'
+                    ' set to type GN')
+      vals['gn_args'] = os.environ.get('GN_ARGS', '')
+
     return vals
 
   def ReadConfigFile(self):
     if not self.Exists(self.args.config_file):
       raise MBErr('config file not found at %s' % self.args.config_file)
 
     try:
       contents = ast.literal_eval(self.ReadFile(self.args.config_file))
     except SyntaxError as e:
       raise MBErr('Failed to parse config file "%s": %s' %
@@ skipping 23 matching lines @@
                   (self.args.master, self.args.config_file))
 
     if not self.args.builder in self.masters[self.args.master]:
       raise MBErr('Builder name "%s"  not found under masters[%s] in "%s"' %
                   (self.args.builder, self.args.master, self.args.config_file))
 
     return self.masters[self.args.master][self.args.builder]
 
   def FlattenConfig(self, config):
     mixins = self.configs[config]
-    vals = {
+    vals = self.DefaultConfigVals()
+    visited = []
+    self.FlattenMixins(mixins, vals, visited)
+    return vals
+
+  def DefaultConfigVals(self):
+    return {
       'type': None,
       'gn_args': [],
       'gyp_defines': '',
       'gyp_crosscompile': False,
     }
 
-    visited = []
-    self.FlattenMixins(mixins, vals, visited)
-    return vals
-
   def FlattenMixins(self, mixins, vals, visited):
     for m in mixins:
       if m not in self.mixins:
         raise MBErr('Unknown mixin "%s"' % m)
 
       # TODO: check for cycles in mixins.
 
       visited.append(m)
 
       mixin_vals = self.mixins[m]
@@ skipping 622 matching lines @@
 
 if __name__ == '__main__':
   try:
     sys.exit(main(sys.argv[1:]))
   except MBErr as e:
     print(e)
     sys.exit(1)
   except KeyboardInterrupt:
     print("interrupted, exiting", stream=sys.stderr)
     sys.exit(130)