Mojo JS bindings: simplify mojo.connectToService() usage - Part 2

mojo/public/tools/bindings/generators/js_templates/interface_definition.tmpl

 {%- for method in interface.methods %}
   var k{{interface.name}}_{{method.name}}_Name = {{method.ordinal}};
 {%- endfor %}
 
   function {{interface.name}}Proxy(receiver) {
     this.receiver_ = receiver;
   }
 
 {%- for method in interface.methods %}
   {{interface.name}}Proxy.prototype.{{method.name|stylize_method}} = function(
@@ skipping 85 matching lines @@
         var message = builder.finish();
         responder.accept(message);
       });
 {%- endif %}
 {%- endfor %}
     default:
       return Promise.reject(Error("Unhandled message: " + reader.messageName));
     }
   };
 
+  function {{interface.name}}DelegatingStub() {
+  }
+
+  {{interface.name}}DelegatingStub.prototype =
+      Object.create({{interface.name}}Stub.prototype);

[abarth-chromium, 2014/10/10 17:45:07]

It would be nice if the main stub was delegating instead of having to subclass. 
We talked about this in person and agreed to make that change in a separate step
after updating all the existing clients.

+
+  {{interface.name}}DelegatingStub.prototype.callDelegateMethod$ = function(methodName, args) {
+    var method = this.delegate$ && this.delegate$[methodName];
+    return method && method.apply(this.delegate$, args);
+  }
+
+{%- for method in interface.methods %}
+{%-   set method_name = method.name|stylize_method %}
+  {{interface.name}}DelegatingStub.prototype.{{method_name}} = function() {
+    return this.callDelegateMethod$("{{method_name}}", arguments);
+  }
+{%- endfor %}

[abarth-chromium, 2014/10/10 17:45:07]

When we merge DelegatingStub into the Sub, we should have accept dispatch to the
delegate directly.  I like that you've made it not an error to not implement
various methods.  We should keep that when we merge the two dispatching
mechanisms.

+
 {#--- Validation #}
 
   function validate{{interface.name}}Request(messageValidator) {
 {%- if not(interface.methods) %}
     return validator.validationError.NONE;
 {%- else %}
     var message = messageValidator.message;
     var paramsClass = null;
     switch (message.getName()) {
 {%-   for method in interface.methods %}
@@ skipping 33 matching lines @@
     if (paramsClass === null)
       return validator.validationError.NONE;
     return paramsClass.validate(messageValidator, messageValidator.message.getHeaderNumBytes());
 {%- endif %}
   }
 
   var {{interface.name}} = {
     name: '{{namespace|replace(".","::")}}::{{interface.name}}',
     proxyClass: {{interface.name}}Proxy,
     stubClass: {{interface.name}}Stub,
+    delegatingStubClass: {{interface.name}}DelegatingStub,
     validateRequest: validate{{interface.name}}Request,
 {%- if interface|has_callbacks %}
     validateResponse: validate{{interface.name}}Response,
 {%- else %}
     validateResponse: null,
 {%- endif %}
   };
 {#--- Interface Constants #}
 {%- for constant in interface.constants %}
   {{interface.name}}.{{constant.name}} = {{constant.value|expression_to_text}},
 {%-   endfor %}
 {#--- Interface Enums #}
 {%- from "enum_definition.tmpl" import enum_def -%}
 {%- for enum in interface.enums %}
   {{ enum_def("%s.%s"|format(interface.name, enum.name), enum) }}
 {%-  endfor %}
   {{interface.name}}Stub.prototype.validator = validate{{interface.name}}Request;
 {%- if interface|has_callbacks %}
   {{interface.name}}Proxy.prototype.validator = validate{{interface.name}}Response;
 {%- else %}
   {{interface.name}}Proxy.prototype.validator = null;
 {%- endif %}