JavaScript bindings for Mojo message validation

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

 {%- set namespace_as_string = namespace|replace(".","::") %}
 {%- for method in interface.methods %}
   var k{{interface.name}}_{{method.name}}_Name = {{method.ordinal}};
 {%- endfor %}
 
   function {{interface.name}}Proxy(receiver) {
     this.receiver_ = receiver;
   }
 
   {{interface.name}}Proxy.NAME_ = '{{namespace_as_string}}::{{interface.name}}';
@@ skipping 90 matching lines @@
         var message = builder.finish();
         responder.accept(message);
       });
 {%- endif %}
 {%- endfor %}
     default:
       return Promise.reject(Error("Unhandled message: " + reader.messageName));
     }
   };
 
+{#--- Validation #}
+
+  function validate{{interface.name}}Request(messageValidator) {

[Matt Perry, 2014/08/13 19:31:01]

I wonder if we should add an {{interface.name}} object, with validateRequest and
validateResponse. We could also move constants and enums there.

[hansmuller, 2014/08/13 21:23:40]

That seems reasonable. Currently we put interface scoped constant/enums in both
the Proxy and Stub classes. Are you suggesting that we also put them in an
{{interface.name}} object?

[Matt Perry, 2014/08/13 21:30:44]

That's right. (Though maybe they need to be on the Proxy/Stub objects for other
reasons?)

[hansmuller, 2014/08/13 21:53:21]

I assume so however I haven't seen a JS use case. Applications wouldn't need
access to the validate methods but they would need to use the Proxy/Stub
classes. So maybe leaving things they way they are would be OK.

+{%- if interface.methods %}

[Matt Perry, 2014/08/13 19:31:01]

nit: this would be slightly clearer to me if you inverted the if expression,
since the else block is so much shorter.

[hansmuller, 2014/08/13 21:23:40]

Good point, I'll swap them.

+    var message = messageValidator.message;
+    var paramsClass = null;
+    switch (message.getName()) {
+{%- for method in interface.methods %}
+      case k{{interface.name}}_{{method.name}}_Name:
+{%-   if method.response_parameters == None %}
+        if (!message.expectsResponse() && !message.isResponse())
+          paramsClass = {{interface.name}}_{{method.name}}_Params;
+{%-     else %}
+        if (message.expectsResponse())

[Matt Perry, 2014/08/13 19:31:01]

is it not an error if the message expects a response but has no response params?
or vice versa?

[hansmuller, 2014/08/13 21:23:40]

I believe that the previous clause covers the first case (no response parameters
defined, but the message expects a response). And this clause covers the other
case (response parameters defined but the message doesn't expect a response). 

As I understand it, we don't generate a validation error in either case since
the message will be ignored by the router anyway. I believe the logic for the
C++ case is that same.

+          paramsClass = {{interface.name}}_{{method.name}}_Params;
+{%-     endif %}
+        break;
+{%- endfor %}
+    }
+    if (paramsClass === null)
+      return validator.validationError.NONE;
+    return paramsClass.validate(messageValidator, codec.kMessageHeaderSize);
+{%- else %}
+      return validator.validationError.NONE;
+{%- endif %}
+  }
+
+  function validate{{interface.name}}Response(messageValidator) {
+{%- if interface|has_callbacks %}

[Matt Perry, 2014/08/13 19:31:01]

ditto line 114

[hansmuller, 2014/08/13 21:23:40]

Done.

+    var message = messageValidator.message;
+    var paramsClass = null;
+    switch (message.getName()) {
+{%- for method in interface.methods %}
+{%- if method.response_parameters != None %}
+      case k{{interface.name}}_{{method.name}}_Name:
+        if (message.isResponse())
+          paramsClass = {{interface.name}}_{{method.name}}_ResponseParams;
+        break;
+{%- endif %}
+{%- endfor %}
+    }
+    if (paramsClass === null)
+      return validator.validationError.NONE;
+    return paramsClass.validate(messageValidator, codec.kMessageWithRequestIDHeaderSize);
+{%- else %}
+      return validator.validationError.NONE;
+{%- endif %}
+  }
+
 {#--- Enums #}
 {%  from "enum_definition.tmpl" import enum_def -%}
 {%  for enum in interface.enums %}
   {{enum_def("%sProxy.%s"|format(interface.name, enum.name), enum, module)}}
   {{interface.name}}Stub.{{enum.name}} = {{interface.name}}Proxy.{{enum.name}};
 {%-  endfor %}
 
 {#--- Constants. #}
 {%  for constant in interface.constants %}
   {{interface.name}}Proxy.{{constant.name}} = {{constant.value|expression_to_text}};
   {{interface.name}}Stub.{{constant.name}} = {{interface.name}}Proxy.{{constant.name}};
 {%  endfor %}