Support default values for complex objects in mojom.

mojo/public/bindings/pylib/generate/mojom_generator.py

 # Copyright 2013 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.
 
 """Code shared by the various language-specific code generators."""
 
 import os
 import mojom
 import mojom_pack
 import re
 from functools import partial
 
 def GetStructFromMethod(interface, method):
   """Converts a method's parameters into the fields of a struct."""
   params_class = "%s_%s_Params" % (interface.name, method.name)
   struct = mojom.Struct(params_class)
   for param in method.parameters:
     struct.AddField(param.name, param.kind, param.ordinal)
   struct.packed = mojom_pack.PackedStruct(struct)
   return struct
 
 def GetStructInfo(exported, struct):
   struct.packed = mojom_pack.PackedStruct(struct)
   struct.bytes = mojom_pack.GetByteLayout(struct.packed)
   struct.exported = exported
   return struct
 
+def GetStructByName(structs, name):
+  for struct in structs:
+    if struct.name == name:
+      return struct
+  return None
+
 def IsStringKind(kind):
   return kind.spec == 's'
 
 def IsObjectKind(kind):
   return isinstance(kind, (mojom.Struct, mojom.Array)) or IsStringKind(kind)
 
 def IsHandleKind(kind):
   return kind.spec.startswith('h')
 
 def CamelToUnderscores(camel):
   s = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', camel)
   return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s).lower()
 
 def StudlyCapsToCamel(studly):
   return studly[0].lower() + studly[1:]
 
+def VerifyTokenType(token, expected):
+  """Used to check that arrays and objects are used correctly as default
+  values. Arrays are tokens that look like ('ARRAY', element0, element1...).
+  See mojom_parser.py for their representation.
+  """
+  if not isinstance(token, tuple):
+    raise Exception("Expected token type '%s'. Invalid token '%s'." %
+        (expected, token))
+  if token[0] != expected:
+    raise Exception("Expected token type '%s'. Got '%s'." %
+        (expected, token[0]))
+
 class Generator(object):
   # Pass |output_dir| to emit files to disk. Omit |output_dir| to echo all
   # files to stdout.
   def __init__(self, module, header_dir, output_dir=None):
     self.module = module
     self.header_dir = header_dir
     self.output_dir = output_dir
 
   def GetStructsFromMethods(self):
     result = []
     for interface in self.module.interfaces:
       for method in interface.methods:
         result.append(GetStructFromMethod(interface, method))
     return map(partial(GetStructInfo, False), result)
 
   def GetStructs(self):
     return map(partial(GetStructInfo, True), self.module.structs)
 
   def Write(self, contents, filename):
     if self.output_dir is None:
       print contents
       return
     with open(os.path.join(self.output_dir, filename), "w+") as f:
       f.write(contents)
 
   def GenerateFiles(self):
     raise NotImplementedError("Subclasses must override/implement this method")