Make mojom-generated C++ string constants really constant.

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 198 matching lines @@
       return False
     else:
       return True
   return Check(kind)
 
 
 def GetNativeTypeName(typemapped_kind):
   return _current_typemap[GetFullMojomNameForKind(typemapped_kind)]["typename"]
 
 def GetCppPodType(kind):
-  if mojom.IsStringKind(kind):
-    return "char*"
   return _kind_to_cpp_type[kind]
 
+def FormatConstantDeclaration(constant, nested=False):
+  if mojom.IsStringKind(constant.kind):
+    if nested:
+      return "const char %s[]" % constant.name
+    return "extern const char %s[]" % constant.name
+  return "constexpr %s %s = %s" % (GetCppPodType(constant.kind), constant.name,
+                                   ConstantValue(constant))
+
 def GetCppWrapperType(kind, add_same_module_namespaces=False):
   def _AddOptional(type_name):
     pattern = "WTF::Optional<%s>" if _for_blink else "base::Optional<%s>"
     return pattern % type_name
 
   if IsTypemappedKind(kind):
     type_name = GetNativeTypeName(kind)
     if (mojom.IsNullableKind(kind) and
         not _current_typemap[GetFullMojomNameForKind(kind)][
            "nullable_is_same_type"]):
@@ skipping 177 matching lines @@
 
 def GetUnmappedTypeForSerializer(kind):
   return GetCppDataViewType(kind, qualified=True)
 
 def TranslateConstants(token, kind):
   if isinstance(token, mojom.NamedValue):
     return _NameFormatter(token, _variant).FormatForCpp(
         flatten_nested_kind=True)
 
   if isinstance(token, mojom.BuiltinValue):
-    if token.value == "double.INFINITY" or token.value == "float.INFINITY":
-      return "INFINITY";
-    if token.value == "double.NEGATIVE_INFINITY" or \
-       token.value == "float.NEGATIVE_INFINITY":
-      return "-INFINITY";
-    if token.value == "double.NAN" or token.value == "float.NAN":
-      return "NAN";
+    if token.value == "double.INFINITY":
+      return "std::numeric_limits<double>::infinity()"
+    if token.value == "float.INFINITY":
+      return "std::numeric_limits<float>::infinity()"
+    if token.value == "double.NEGATIVE_INFINITY":
+      return "-std::numeric_limits<double>::infinity()"
+    if token.value == "float.NEGATIVE_INFINITY":
+      return "-std::numeric_limits<float>::infinity()"
+    if token.value == "double.NAN":
+      return "std::numeric_limits<double>::quiet_NaN()"
+    if token.value == "float.NAN":
+      return "std::numeric_limits<float>::quiet_NaN()"
 
   if (kind is not None and mojom.IsFloatKind(kind)):
       return token if token.isdigit() else token + "f";
 
   # Per C++11, 2.14.2, the type of an integer literal is the first of the
   # corresponding list in Table 6 in which its value can be represented. In this
   # case, the list for decimal constants with no suffix is:
   #   int, long int, long long int
   # The standard considers a program ill-formed if it contains an integer
   # literal that cannot be represented by any of the allowed types.
@@ skipping 91 matching lines @@
     "cpp_wrapper_param_type": GetCppWrapperParamType,
     "cpp_data_view_type": GetCppDataViewType,
     "cpp_field_type": GetCppFieldType,
     "cpp_union_field_type": GetCppUnionFieldType,
     "cpp_pod_type": GetCppPodType,
     "cpp_union_getter_return_type": GetUnionGetterReturnType,
     "cpp_union_trait_getter_return_type": GetUnionTraitGetterReturnType,
     "cpp_wrapper_type": GetCppWrapperType,
     "default_value": DefaultValue,
     "expression_to_text": ExpressionToText,
+    "format_constant_declaration": FormatConstantDeclaration,
     "get_container_validate_params_ctor_args":
         GetContainerValidateParamsCtorArgs,
     "get_name_for_kind": GetNameForKind,
     "get_pad": pack.GetPad,
     "get_qualified_name_for_kind": GetQualifiedNameForKind,
     "has_callbacks": mojom.HasCallbacks,
     "has_sync_methods": mojom.HasSyncMethods,
     "requires_context_for_data_view": RequiresContextForDataView,
     "should_inline": ShouldInlineStruct,
     "should_inline_union": ShouldInlineUnion,
@@ skipping 107 matching lines @@
       global _use_once_callback
       _use_once_callback = self.use_once_callback
       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.GenerateModuleSource(),
           self.MatchMojomFilePath("%s%s.cc" % (self.module.name, suffix)))