Mojo: more idiomatic C++ bindings

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 19 matching lines @@
 }
 
 
 def NamespaceToArray(namespace):
   return namespace.split('.') if namespace else []
 
 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)
   return "::".join(parts)
 
 def GetCppType(kind):
   if isinstance(kind, mojom.Struct):
     return "%s_Data*" % GetNameForKind(kind, internal=True)
   if isinstance(kind, mojom.Array):
     return "mojo::internal::Array_Data<%s>*" % GetCppType(kind.kind)
   if isinstance(kind, mojom.Interface):
     return "mojo::MessagePipeHandle"
   if isinstance(kind, mojom.Enum):
     return "int32_t"
   if kind.spec == 's':
     return "mojo::internal::String_Data*"
   return _kind_to_cpp_type[kind]
 
 def GetCppPodType(kind):
   if kind.spec == 's':
     return "char*"
   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':
     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 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):
     return GetNameForKind(kind)
   if kind.spec == 's':
-    return "const mojo::String&"
+    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"
@@ skipping 39 matching lines @@
     raise Exception("Expected EXPRESSION, got" + value)
   return "".join(generator.ExpressionMapper(value,
       lambda token: TranslateConstants(token, module)))
 
 def HasCallbacks(interface):
   for method in interface.methods:
     if method.response_parameters != None:
       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 isinstance(field.kind, (mojom.Array, mojom.Struct)):
+      return False
+  return True
+
 _HEADER_SIZE = 8
 
 class Generator(generator.Generator):
 
   cpp_filters = {
     "cpp_const_wrapper_type": GetCppConstWrapperType,
     "cpp_field_type": GetCppFieldType,
     "cpp_pod_type": GetCppPodType,
     "cpp_result_type": GetCppResultWrapperType,
     "cpp_type": GetCppType,
     "cpp_wrapper_type": GetCppWrapperType,
     "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,
     "is_string_kind": generator.IsStringKind,
     "is_array_kind": lambda kind: isinstance(kind, mojom.Array),
     "is_struct_with_handles": IsStructWithHandles,
     "struct_size": lambda ps: ps.GetTotalSize() + _HEADER_SIZE,
     "struct_from_method": generator.GetStructFromMethod,
     "response_struct_from_method": generator.GetResponseStructFromMethod,
     "stylize_method": generator.StudlyCapsToCamel,
@@ skipping 22 matching lines @@
 
   @UseJinja("cpp_templates/module.cc.tmpl", filters=cpp_filters)
   def GenerateModuleSource(self):
     return self.GetJinjaExports()
 
   def GenerateFiles(self, args):
     self.Write(self.GenerateModuleHeader(), "%s.h" % self.module.name)
     self.Write(self.GenerateModuleInternalHeader(),
         "%s-internal.h" % self.module.name)
     self.Write(self.GenerateModuleSource(), "%s.cc" % self.module.name)