Mojo: more idiomatic C++ bindings

mojo/public/tools/bindings/generators/mojom_cpp_generator.py

Index: mojo/public/tools/bindings/generators/mojom_cpp_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index 52d380aa2e7964b2b853ce7675eec3d96c923e3a..6b7492d5bccd9f3b43cc4872b713e95aea2b3e96 100644
--- a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -37,8 +37,8 @@ def GetNameForKind(kind, internal = False):
   parts = []
   if kind.imported_from:
     parts.extend(NamespaceToArray(kind.imported_from["namespace"]))
-    if internal:
-      parts.append("internal")
+  if internal:
+    parts.append("internal")
   if kind.parent_kind:
     parts.append(kind.parent_kind.name)
   parts.append(kind.name)
@@ -63,21 +63,35 @@ def GetCppPodType(kind):
   return _kind_to_cpp_type[kind]
 
 def GetCppArrayArgWrapperType(kind):
-  if isinstance(kind, (mojom.Struct, mojom.Enum)):
+  if isinstance(kind, mojom.Enum):
     return GetNameForKind(kind)
+  if isinstance(kind, mojom.Struct):
+    return "%sPtr" % GetNameForKind(kind)
   if isinstance(kind, mojom.Array):
-    return "mojo::Array<%s >" % GetCppArrayArgWrapperType(kind.kind)
+    return "mojo::Array<%s> " % GetCppArrayArgWrapperType(kind.kind)
   if isinstance(kind, mojom.Interface):
     raise Exception("Arrays of interfaces not yet supported!")
   if kind.spec == 's':
     return "mojo::String"
+  if kind.spec == 'h':
+    return "mojo::ScopedHandle"
+  if kind.spec == 'h:d:c':
+    return "mojo::ScopedDataPipeConsumerHandle"
+  if kind.spec == 'h:d:p':
+    return "mojo::ScopedDataPipeProducerHandle"
+  if kind.spec == 'h:m':
+    return "mojo::ScopedMessagePipeHandle"
+  if kind.spec == 'h:s':
+    return "mojo::ScopedSharedBufferHandle"
   return _kind_to_cpp_type[kind]
 
 def GetCppResultWrapperType(kind):
-  if isinstance(kind, (mojom.Struct, mojom.Enum)):
+  if isinstance(kind, mojom.Enum):
     return GetNameForKind(kind)
+  if isinstance(kind, mojom.Struct):
+    return "%sPtr" % GetNameForKind(kind)
   if isinstance(kind, mojom.Array):
-    return "mojo::Array<%s >" % GetCppArrayArgWrapperType(kind.kind)
+    return "mojo::Array<%s>" % GetCppArrayArgWrapperType(kind.kind)
   if isinstance(kind, mojom.Interface):
     return "%sPtr" % kind.name
   if kind.spec == 's':
@@ -95,23 +109,33 @@ def GetCppResultWrapperType(kind):
   return _kind_to_cpp_type[kind]
 
 def GetCppWrapperType(kind):
-  if isinstance(kind, (mojom.Struct, mojom.Enum)):
+  if isinstance(kind, mojom.Enum):
     return GetNameForKind(kind)
+  if isinstance(kind, mojom.Struct):
+    return "%sPtr" % GetNameForKind(kind)
   if isinstance(kind, mojom.Array):
-    return "mojo::Array<%s >" % GetCppArrayArgWrapperType(kind.kind)
+    return "mojo::Array<%s>" % GetCppArrayArgWrapperType(kind.kind)
   if isinstance(kind, mojom.Interface):
-    return "mojo::Passable<mojo::MessagePipeHandle>"
+    return "mojo::ScopedMessagePipeHandle"
   if kind.spec == 's':
     return "mojo::String"
-  if generator.IsHandleKind(kind):
-    return "mojo::Passable<%s>" % _kind_to_cpp_type[kind]
+  if kind.spec == 'h':
+    return "mojo::ScopedHandle"
+  if kind.spec == 'h:d:c':
+    return "mojo::ScopedDataPipeConsumerHandle"
+  if kind.spec == 'h:d:p':
+    return "mojo::ScopedDataPipeProducerHandle"
+  if kind.spec == 'h:m':
+    return "mojo::ScopedMessagePipeHandle"
+  if kind.spec == 'h:s':
+    return "mojo::ScopedSharedBufferHandle"
   return _kind_to_cpp_type[kind]
 
 def GetCppConstWrapperType(kind):
   if isinstance(kind, mojom.Struct):
-    return "const %s&" % GetNameForKind(kind)
+    return "%sPtr" % GetNameForKind(kind)
   if isinstance(kind, mojom.Array):
-    return "const mojo::Array<%s >&" % GetCppArrayArgWrapperType(kind.kind)
+    return "mojo::Array<%s>" % GetCppArrayArgWrapperType(kind.kind)
   if isinstance(kind, mojom.Interface):
     return "%sPtr" % kind.name
   if isinstance(kind, mojom.Enum):
@@ -177,6 +201,15 @@ def HasCallbacks(interface):
       return True
   return False
 
+def ShouldInlineStruct(struct):
+  # TODO(darin): Base this on the size of the wrapper class.
+  if len(struct.fields) > 4:
+    return False
+  for field in struct.fields:
+    if generator.IsHandleKind(field.kind) or generator.IsObjectKind(field.kind):
+      return False
+  return True
+
 _HEADER_SIZE = 8
 
 class Generator(generator.Generator):
@@ -191,7 +224,9 @@ class Generator(generator.Generator):
     "expression_to_text": ExpressionToText,
     "get_pad": pack.GetPad,
     "has_callbacks": HasCallbacks,
+    "should_inline": ShouldInlineStruct,
     "is_enum_kind": generator.IsEnumKind,
+    "is_move_only_kind": generator.IsMoveOnlyKind,
     "is_handle_kind": generator.IsHandleKind,
     "is_interface_kind": generator.IsInterfaceKind,
     "is_object_kind": generator.IsObjectKind,