Mojo C++ bindings: add a new mode to generator to use native STL/WTF types

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 18 matching lines @@
   mojom.UINT16:       "U",
   mojom.UINT32:       "U",
   mojom.FLOAT:        "f",
   mojom.UINT64:       "ULL",
 }
 
 # TODO(rockot): Get rid of these globals. This requires some refactoring of the
 # generator library code so that filters can use the generator as context.
 _current_typemap = {}
 _for_blink = False
+_use_new_wrapper_types = False
 # TODO(rockot, yzshen): The variant handling is kind of a hack currently. Make
 # it right.
 _variant = None
 
 
 class _NameFormatter(object):
   """A formatter for the names of kinds or values."""
 
   def __init__(self, token, variant):
     self._token = token
@@ skipping 50 matching lines @@
     if self._token.imported_from:
       return NamespaceToArray(self._token.imported_from["namespace"])
     elif hasattr(self._token, "module"):
       return NamespaceToArray(self._token.module.namespace)
     return []
 
 
 def ConstantValue(constant):
   return ExpressionToText(constant.value, kind=constant.kind)
 
+# TODO(yzshen): Revisit the default value feature. It was designed prior to
+# custom type mapping.
 def DefaultValue(field):
   if field.default:
     if mojom.IsStructKind(field.kind):
       assert field.default == "default"
-      return "%s::New()" % GetNameForKind(field.kind)
+      if not IsTypemappedKind(field.kind):
+        return "%s::New()" % GetNameForKind(field.kind)
     return ExpressionToText(field.default, kind=field.kind)
-  if mojom.IsArrayKind(field.kind) or mojom.IsMapKind(field.kind):
-    return "nullptr";
-  if mojom.IsStringKind(field.kind):
-    return "" if _for_blink else "nullptr"
+  if not _use_new_wrapper_types:
+    if mojom.IsArrayKind(field.kind) or mojom.IsMapKind(field.kind):
+      return "nullptr";
+    if mojom.IsStringKind(field.kind):
+      return "" if _for_blink else "nullptr"
   return ""
 
 def NamespaceToArray(namespace):
   return namespace.split(".") if namespace else []
 
 def GetNameForKind(kind, internal=False):
   return _NameFormatter(kind, _variant).FormatForCpp(internal=internal)
 
 def GetQualifiedNameForKind(kind, internal=False):
   return _NameFormatter(kind, _variant).FormatForCpp(
@@ skipping 19 matching lines @@
   return _kind_to_cpp_type[kind]
 
 def GetCppWrapperType(kind):
   if IsTypemappedKind(kind):
     return GetNativeTypeName(kind)
   if mojom.IsEnumKind(kind):
     return GetNameForKind(kind)
   if mojom.IsStructKind(kind) or mojom.IsUnionKind(kind):
     return "%sPtr" % GetNameForKind(kind)
   if mojom.IsArrayKind(kind):
-    pattern = "mojo::WTFArray<%s>" if _for_blink else "mojo::Array<%s>"
+    pattern = None
+    if _use_new_wrapper_types:
+      if mojom.IsNullableKind(kind):
+        pattern = ("WTF::Optional<WTF::Vector<%s>>" if _for_blink else
+            "base::Optional<std::vector<%s>>")
+      else:
+        pattern = "WTF::Vector<%s>" if _for_blink else "std::vector<%s>"
+    else:
+      pattern = "mojo::WTFArray<%s>" if _for_blink else "mojo::Array<%s>"
     return pattern % GetCppWrapperType(kind.kind)
   if mojom.IsMapKind(kind):
-    pattern = "mojo::WTFMap<%s, %s>" if _for_blink else "mojo::Map<%s, %s>"
+    pattern = None
+    if _use_new_wrapper_types:
+      if mojom.IsNullableKind(kind):
+        pattern = ("WTF::Optional<WTF::HashMap<%s, %s>>" if _for_blink else
+                   "base::Optional<std::unordered_map<%s, %s>>")
+      else:
+        pattern = ("WTF::HashMap<%s, %s>" if _for_blink else
+                   "std::unordered_map<%s, %s>")
+    else:
+      pattern = "mojo::WTFMap<%s, %s>" if _for_blink else "mojo::Map<%s, %s>"
     return pattern % (GetCppWrapperType(kind.key_kind),
                       GetCppWrapperType(kind.value_kind))
   if mojom.IsInterfaceKind(kind):
     return "%sPtr" % GetNameForKind(kind)
   if mojom.IsInterfaceRequestKind(kind):
     return "%sRequest" % GetNameForKind(kind.kind)
   if mojom.IsAssociatedInterfaceKind(kind):
     return "%sAssociatedPtrInfo" % GetNameForKind(kind.kind)
   if mojom.IsAssociatedInterfaceRequestKind(kind):
     return "%sAssociatedRequest" % GetNameForKind(kind.kind)
   if mojom.IsStringKind(kind):
-    return "WTF::String" if _for_blink else "mojo::String"
+    if _for_blink:
+      return "WTF::String"
+    if not _use_new_wrapper_types:
+      return "mojo::String"
+    return ("base::Optional<std::string>" if mojom.IsNullableKind(kind) else
+            "std::string")
   if mojom.IsGenericHandleKind(kind):
     return "mojo::ScopedHandle"
   if mojom.IsDataPipeConsumerKind(kind):
     return "mojo::ScopedDataPipeConsumerHandle"
   if mojom.IsDataPipeProducerKind(kind):
     return "mojo::ScopedDataPipeProducerHandle"
   if mojom.IsMessagePipeKind(kind):
     return "mojo::ScopedMessagePipeHandle"
   if mojom.IsSharedBufferKind(kind):
     return "mojo::ScopedSharedBufferHandle"
   if not kind in _kind_to_cpp_type:
     raise Exception("Unrecognized kind %s" % kind.spec)
   return _kind_to_cpp_type[kind]
 
-def ShouldPassParamByValue(kind):
+def IsMoveOnlyKind(kind):
   if IsTypemappedKind(kind):
     if mojom.IsEnumKind(kind):
-      return True
+      return False
+    # TODO(yzshen): Change the attribute to "move_only".
     return _current_typemap[GetFullMojomNameForKind(kind)]["pass_by_value"]
-  return not mojom.IsStringKind(kind)
+  if mojom.IsStructKind(kind) or mojom.IsUnionKind(kind):
+    return True
+  if mojom.IsArrayKind(kind):
+    return IsMoveOnlyKind(kind.kind) if _use_new_wrapper_types else True
+  if mojom.IsMapKind(kind):
+    return IsMoveOnlyKind(kind.value_kind) if _use_new_wrapper_types else True
+  if mojom.IsAnyHandleOrInterfaceKind(kind):
+    return True
+  return False
+
+def ShouldPassParamByValue(kind):
+  return (not mojom.IsReferenceKind(kind)) or IsMoveOnlyKind(kind)
 
 def GetCppWrapperParamType(kind):
   cpp_wrapper_type = GetCppWrapperType(kind)
   return (cpp_wrapper_type if ShouldPassParamByValue(kind)
                            else "const %s&" % cpp_wrapper_type)
 
 def GetCppFieldType(kind):
   if mojom.IsStructKind(kind):
     return ("mojo::internal::Pointer<%s>" %
         GetNameForKind(kind, internal=True))
@@ skipping 98 matching lines @@
   return "%s%s" % (token, _kind_to_cpp_literal_suffix.get(kind, ""))
 
 def ExpressionToText(value, kind=None):
   return TranslateConstants(value, kind)
 
 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 mojom.IsMoveOnlyKind(field.kind):
+    if mojom.IsReferenceKind(field.kind) and not mojom.IsStringKind(field.kind):
       return False
   return True
 
 def ShouldInlineUnion(union):
-  return not any(mojom.IsMoveOnlyKind(field.kind) for field in union.fields)
+  return not any(
+      mojom.IsReferenceKind(field.kind) and not mojom.IsStringKind(field.kind)
+           for field in union.fields)
 
 def GetContainerValidateParamsCtorArgs(kind):
   if mojom.IsStringKind(kind):
     expected_num_elements = 0
     element_is_nullable = False
     key_validate_params = "nullptr"
     element_validate_params = "nullptr"
     enum_validate_func = "nullptr"
   elif mojom.IsMapKind(kind):
     expected_num_elements = 0
@@ skipping 93 matching lines @@
       "imports": self.module.imports,
       "kinds": self.module.kinds,
       "enums": self.module.enums,
       "structs": self.GetStructs(),
       "unions": self.GetUnions(),
       "interfaces": self.GetInterfaces(),
       "variant": self.variant,
       "extra_traits_headers": self.GetExtraTraitsHeaders(),
       "extra_public_headers": self.GetExtraPublicHeaders(),
       "for_blink": self.for_blink,
+      "use_new_wrapper_types": self.use_new_wrapper_types,
     }
 
   @staticmethod
   def GetTemplatePrefix():
     return "cpp_templates"
 
   @classmethod
   def GetFilters(cls):
     return cls.cpp_filters
 
   @UseJinja("module.h.tmpl")
   def GenerateModuleHeader(self):
     return self.GetJinjaExports()
 
   @UseJinja("module-internal.h.tmpl")
   def GenerateModuleInternalHeader(self):
     return self.GetJinjaExports()
 
   @UseJinja("module.cc.tmpl")
   def GenerateModuleSource(self):
     return self.GetJinjaExports()
 
   def GenerateFiles(self, args):
     global _current_typemap
     _current_typemap = self.typemap
     global _for_blink
     _for_blink = self.for_blink
+    global _use_new_wrapper_types
+    _use_new_wrapper_types = self.use_new_wrapper_types
     global _variant
     _variant = self.variant
     suffix = "-%s" % self.variant if self.variant else ""
     self.Write(self.GenerateModuleHeader(),
         self.MatchMojomFilePath("%s%s.h" % (self.module.name, suffix)))
     self.Write(self.GenerateModuleInternalHeader(),
         self.MatchMojomFilePath("%s%s-internal.h" % (self.module.name, suffix)))
     self.Write(self.GenerateModuleSource(),
         self.MatchMojomFilePath("%s%s.cc" % (self.module.name, suffix)))