[Mojo] Make javascript enums extensible.

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

Index: mojo/public/tools/bindings/generators/mojom_js_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_js_generator.py b/mojo/public/tools/bindings/generators/mojom_js_generator.py
index e2df5176e25eef78beded602e2d12c988fcf0408..4796a2c15ee776ae8c305f0a6ba7a00c0a60b728 100644
--- a/mojo/public/tools/bindings/generators/mojom_js_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_js_generator.py
@@ -139,7 +139,13 @@ def CodecType(kind):
 
 
 def ElementCodecType(kind):

[mbjorge, 2016/09/30 19:10:48]

I wasn't totally sure if this was the best place for this since I don't think
the enum kind.name is really a codec type? But it kept the type lookup in
JavaScriptValidateArrayParams and JavascriptValidateMapParams cleaner. 

[Ken Rockot(use gerrit already), 2016/09/30 21:14:38]

I think it would make more sense to just add a codec type for enums in see
mojo/public/js/codec.js. It could be constructed over the generated enum type
similar to how the PointerTo codec is constructed for struct types.

-  return "codec.PackedBool" if mojom.IsBoolKind(kind) else CodecType(kind)
+  if mojom.IsBoolKind(kind):
+    return "codec.PackedBool"
+
+  if mojom.IsEnumKind(kind):
+    return kind.name
+
+  return CodecType(kind)
 
 def JavaScriptDecodeSnippet(kind):
   if (kind in mojom.PRIMITIVES or mojom.IsUnionKind(kind) or
@@ -228,6 +234,11 @@ def JavaScriptValidateArrayParams(field):
        expected_dimension_sizes)
 
 
+def JavaScriptValidateEnumParams(field):
+  nullable = JavaScriptNullableParam(field)
+  enum_type = JavaScriptType(field.kind)
+  return "%s, %s" % (enum_type, nullable)
+
 def JavaScriptValidateStructParams(field):
   nullable = JavaScriptNullableParam(field)
   struct_type = JavaScriptType(field.kind)
@@ -316,6 +327,9 @@ def ExpressionToText(value):
 def IsArrayPointerField(field):
   return mojom.IsArrayKind(field.kind)
 
+def IsEnumField(field):
+  return mojom.IsEnumKind(field.kind)
+
 def IsStringPointerField(field):
   return mojom.IsStringKind(field.kind)
 
@@ -355,6 +369,7 @@ class Generator(generator.Generator):
     "has_callbacks": mojom.HasCallbacks,
     "is_array_pointer_field": IsArrayPointerField,
     "is_bool_field": IsBoolField,
+    "is_enum_field": IsEnumField,
     "is_map_pointer_field": IsMapPointerField,
     "is_struct_pointer_field": IsStructPointerField,
     "is_string_pointer_field": IsStringPointerField,
@@ -367,6 +382,7 @@ class Generator(generator.Generator):
     "js_stub_method_parameter_value": JavaScriptStubMethodParameterValue,
     "stylize_method": generator.StudlyCapsToCamel,
     "validate_array_params": JavaScriptValidateArrayParams,
+    "validate_enum_params": JavaScriptValidateEnumParams,
     "validate_handle_params": JavaScriptValidateHandleParams,
     "validate_interface_params": JavaScriptValidateInterfaceParams,
     "validate_map_params": JavaScriptValidateMapParams,