Cpp bindings: Return false from Validator::Accept() on unrecognized message or invalid flags

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

Index: mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
index 308c8b67a5060845834470782594e599e915e6a6..d7ff69f16bad9e183305f808f2a1e905002ac939 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
@@ -221,16 +221,25 @@ bool {{class_name}}Stub::AcceptWithResponder(
 
 bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
 {%- if interface.methods %}
+  if (message->has_flag(mojo::internal::kMessageIsResponse)) {
+    ReportValidationError(
+        mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAG_COMBINATION);

[yzshen1, 2015/03/03 18:05:37]

(1) Do you think we should rename this error? -- because the fact that it is
invalid is NOT because the flag "combination" is invalid. The error was designed
to indicate error such as having ExpectsResponse and IsResponse at the same
time.

(2) Please add tests for all the new failures.

[rudominer, 2015/03/04 00:12:01]

Let's do this in a separate CL. I filed b/463684
Done

+    return false;
+  }
   switch (message->header()->name) {
 {%-   for method in interface.methods %}
     case internal::k{{class_name}}_{{method.name}}_Name: {
 {%-     if method.response_parameters != None %}
-      if (!message->has_flag(mojo::internal::kMessageExpectsResponse))
-        break;
+      if (!message->has_flag(mojo::internal::kMessageExpectsResponse)) {
+        ReportValidationError(
+            mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAG_COMBINATION);
+        return false;
+      }
 {%-     else %}
-      if (message->has_flag(mojo::internal::kMessageExpectsResponse) ||
-          message->has_flag(mojo::internal::kMessageIsResponse)) {
-        break;
+      if (message->has_flag(mojo::internal::kMessageExpectsResponse)) {
+        ReportValidationError(
+            mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAG_COMBINATION);
+        return false;
       }
 {%-     endif %}
       mojo::internal::BoundsChecker bounds_checker(
@@ -243,6 +252,12 @@ bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
       break;
     }
 {%-   endfor %}
+    default: {
+      // Unrecognized message.
+      ReportValidationError(
+          mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD);
+      return false;
+    }
   }
 {%- endif %}
 
@@ -258,11 +273,14 @@ bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
 
 bool {{class_name}}ResponseValidator::Accept(mojo::Message* message) {
 {%- if interface.methods %}
+  if (!message->has_flag(mojo::internal::kMessageIsResponse)) {
+    ReportValidationError(
+        mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAG_COMBINATION);
+    return false;
+  }
   switch (message->header()->name) {
 {%-   for method in interface.methods if method.response_parameters != None %}
     case internal::k{{class_name}}_{{method.name}}_Name: {
-      if (!message->has_flag(mojo::internal::kMessageIsResponse))
-        break;
       mojo::internal::BoundsChecker bounds_checker(
           message->payload(), message->payload_num_bytes(),
           message->handles()->size());
@@ -273,6 +291,12 @@ bool {{class_name}}ResponseValidator::Accept(mojo::Message* message) {
       break;
     }
 {%-   endfor %}
+    default: {
+      // Unrecognized message.
+      ReportValidationError(
+          mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD);
+      return false;
+    }
   }
 {%- endif %}