Implement unions as members of structs.

mojo/public/tools/bindings/generators/mojom_cpp_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.
 
 """Generates C++ source files from a mojom.Module."""
 
 import mojom.generate.generator as generator
 import mojom.generate.module as mojom
 import mojom.generate.pack as pack
 from mojom.generate.template_expander import UseJinja
@@ skipping 49 matching lines @@
   parts = []
   if kind.imported_from:
     parts.extend(NamespaceToArray(kind.imported_from["namespace"]))
   if internal:
     parts.append("internal")
   if kind.parent_kind:
     parts.append(kind.parent_kind.name)
   parts.append(kind.name)
   return "::".join(parts)
 
 def GetCppType(kind):

[yzshen1, 2015/02/17 19:34:35]

There are quite a few of GetXXXType(), they all need to properly handle union.

[azani, 2015/02/18 00:27:58]

If that's ok with you, I would rather add them as they become needed. Figuring
out exactly what the right type to return is not always trivial and I would
rather do so in the context of making the feature work rather than more
abstractly up front.

[yzshen1, 2015/02/25 21:06:59]

I am a little concerned to leave these set of functions in inconsistent state.
Hmm... :/

   if mojom.IsArrayKind(kind):
     return "mojo::internal::Array_Data<%s>*" % GetCppType(kind.kind)
   if mojom.IsMapKind(kind):
     return "mojo::internal::Map_Data<%s, %s>*" % (
       GetCppType(kind.key_kind), GetCppType(kind.value_kind))
   if mojom.IsStructKind(kind):
     return "%s_Data*" % GetNameForKind(kind, internal=True)
   if mojom.IsInterfaceKind(kind) or mojom.IsInterfaceRequestKind(kind):
     return "mojo::MessagePipeHandle"
   if mojom.IsEnumKind(kind):
@@ skipping 59 matching lines @@
     return "mojo::ScopedDataPipeProducerHandle"
   if mojom.IsMessagePipeKind(kind):
     return "mojo::ScopedMessagePipeHandle"
   if mojom.IsSharedBufferKind(kind):
     return "mojo::ScopedSharedBufferHandle"
   return _kind_to_cpp_type[kind]
 
 def GetCppWrapperType(kind):
   if mojom.IsEnumKind(kind):
     return GetNameForKind(kind)
-  if mojom.IsStructKind(kind):
+  if mojom.IsStructKind(kind) or mojom.IsUnionKind(kind):
     return "%sPtr" % GetNameForKind(kind)
   if mojom.IsArrayKind(kind):
     return "mojo::Array<%s>" % GetCppArrayArgWrapperType(kind.kind)
   if mojom.IsMapKind(kind):
     return "mojo::Map<%s, %s>" % (GetCppArrayArgWrapperType(kind.key_kind),
                                   GetCppArrayArgWrapperType(kind.value_kind))
   if mojom.IsInterfaceKind(kind):
     return "%sPtr" % GetNameForKind(kind)
   if mojom.IsInterfaceRequestKind(kind):
     raise Exception("InterfaceRequest fields not supported!")
@@ skipping 38 matching lines @@
   if mojom.IsSharedBufferKind(kind):
     return "mojo::ScopedSharedBufferHandle"
   if not kind in _kind_to_cpp_type:
     print "missing:", kind.spec
   return _kind_to_cpp_type[kind]
 
 def GetCppFieldType(kind):
   if mojom.IsStructKind(kind):
     return ("mojo::internal::StructPointer<%s_Data>" %
         GetNameForKind(kind, internal=True))
+  if mojom.IsUnionKind(kind):
+    return "%s_Data" % GetNameForKind(kind, internal=True)
   if mojom.IsArrayKind(kind):
     return "mojo::internal::ArrayPointer<%s>" % GetCppType(kind.kind)
   if mojom.IsMapKind(kind):
     return ("mojo::internal::StructPointer<mojo::internal::Map_Data<%s, %s>>" %
             (GetCppType(kind.key_kind), GetCppType(kind.value_kind)))
   if mojom.IsInterfaceKind(kind) or mojom.IsInterfaceRequestKind(kind):
     return "mojo::MessagePipeHandle"
   if mojom.IsEnumKind(kind):
     return GetNameForKind(kind)
   if mojom.IsStringKind(kind):
@@ skipping 164 matching lines @@
   def GenerateModuleSource(self):
     return self.GetJinjaExports()
 
   def GenerateFiles(self, args):
     self.Write(self.GenerateModuleHeader(),
         self.MatchMojomFilePath("%s.h" % self.module.name))
     self.Write(self.GenerateModuleInternalHeader(),
         self.MatchMojomFilePath("%s-internal.h" % self.module.name))
     self.Write(self.GenerateModuleSource(),
         self.MatchMojomFilePath("%s.cc" % self.module.name))