Mojo: Report bindings validation errors via MojoNotifyBadMessage

mojo/public/cpp/bindings/lib/router.cc

Index: mojo/public/cpp/bindings/lib/router.cc
diff --git a/mojo/public/cpp/bindings/lib/router.cc b/mojo/public/cpp/bindings/lib/router.cc
index da5f34b1df57ce4bbfaf8668061d2bbde6bc3e49..2107a32facfd3c841b5c57ef24fda230c25baf8c 100644
--- a/mojo/public/cpp/bindings/lib/router.cc
+++ b/mojo/public/cpp/bindings/lib/router.cc
@@ -41,32 +41,33 @@ class ResponderThunk : public MessageReceiverWithStatus {
       // We raise an error to signal the calling application that an error
       // condition occurred. Without this the calling application would have no
       // way of knowing it should stop waiting for a response.
+      Error error(Error::Type::REQUEST_CANCELED);
       if (task_runner_->RunsTasksOnCurrentThread()) {
         // Please note that even if this code is run from a different task
         // runner on the same thread as |task_runner_|, it is okay to directly
         // call Router::RaiseError(), because it will raise error from the
         // correct task runner asynchronously.
         if (router_)
-          router_->RaiseError();
+          router_->RaiseError(std::move(error));
       } else {
         task_runner_->PostTask(FROM_HERE,
-                               base::Bind(&Router::RaiseError, router_));
+                               base::Bind(&Router::RaiseError, router_,
+                                          base::Passed(&error)));
       }
     }
   }
 
   // MessageReceiver implementation:
-  bool Accept(Message* message) override {
+  bool Accept(Message* message, Error* error) override {
     DCHECK(task_runner_->RunsTasksOnCurrentThread());
     accept_was_invoked_ = true;
     DCHECK(message->has_flag(kMessageIsResponse));
 
-    bool result = false;
-
     if (router_)
-      result = router_->Accept(message);
+      return router_->Accept(message, error);
 
-    return result;
+    *error = Error(Error::Type::RESPONSE_DROPPED);
+    return false;
   }
 
   // MessageReceiverWithStatus implementation:
@@ -108,8 +109,9 @@ Router::HandleIncomingMessageThunk::HandleIncomingMessageThunk(Router* router)
 Router::HandleIncomingMessageThunk::~HandleIncomingMessageThunk() {
 }
 
-bool Router::HandleIncomingMessageThunk::Accept(Message* message) {
-  return router_->HandleIncomingMessage(message);
+bool Router::HandleIncomingMessageThunk::Accept(Message* message,
+                                                Error* error) {
+  return router_->HandleIncomingMessage(message, error);
 }
 
 // ----------------------------------------------------------------------------
@@ -138,13 +140,15 @@ Router::Router(ScopedMessagePipeHandle message_pipe,
 
 Router::~Router() {}
 
-bool Router::Accept(Message* message) {
+bool Router::Accept(Message* message, Error* error) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!message->has_flag(kMessageExpectsResponse));
-  return connector_.Accept(message);
+  return connector_.Accept(message, error);
 }
 
-bool Router::AcceptWithResponder(Message* message, MessageReceiver* responder) {
+bool Router::AcceptWithResponder(Message* message,
+                                 MessageReceiver* responder,
+                                 Error* error) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(message->has_flag(kMessageExpectsResponse));
 
@@ -155,7 +159,7 @@ bool Router::AcceptWithResponder(Message* message, MessageReceiver* responder) {
 
   bool is_sync = message->has_flag(kMessageIsSync);
   message->set_request_id(request_id);
-  if (!connector_.Accept(message))
+  if (!connector_.Accept(message, error))
     return false;
 
   if (!is_sync) {
@@ -178,7 +182,10 @@ bool Router::AcceptWithResponder(Message* message, MessageReceiver* responder) {
     DCHECK_EQ(&response_received, iter->second->response_received);
     if (response_received) {
       std::unique_ptr<Message> response = std::move(iter->second->response);
-      ignore_result(sync_responder->Accept(response.get()));
+
+      Error send_response_error;
+      ignore_result(sync_responder->Accept(response.get(),
+                                           &send_response_error));
     }
     sync_responses_.erase(iter);
   }
@@ -193,7 +200,7 @@ void Router::EnableTestingMode() {
   connector_.set_enforce_errors_from_incoming_receiver(false);
 }
 
-bool Router::HandleIncomingMessage(Message* message) {
+bool Router::HandleIncomingMessage(Message* message, Error* error) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   const bool during_sync_call =
@@ -214,7 +221,7 @@ bool Router::HandleIncomingMessage(Message* message) {
     return true;
   }
 
-  return HandleMessageInternal(message);
+  return HandleMessageInternal(message, error);
 }
 
 void Router::HandleQueuedMessages() {
@@ -226,12 +233,13 @@ void Router::HandleQueuedMessages() {
     std::unique_ptr<Message> message(std::move(pending_messages_.front()));
     pending_messages_.pop();
 
-    bool result = HandleMessageInternal(message.get());
+    Error error;
+    bool result = HandleMessageInternal(message.get(), &error);
     if (!weak_self)
       return;
 
     if (!result && !testing_mode_) {
-      connector_.RaiseError();
+      connector_.RaiseError(std::move(error));
       break;
     }
   }
@@ -245,14 +253,17 @@ void Router::HandleQueuedMessages() {
     OnConnectionError();
 }
 
-bool Router::HandleMessageInternal(Message* message) {
+bool Router::HandleMessageInternal(Message* message, Error* error) {
   if (message->has_flag(kMessageExpectsResponse)) {
-    if (!incoming_receiver_)
+    if (!incoming_receiver_) {
+      *error = Error(Error::Type::REQUEST_DROPPED);
       return false;
+    }
 
     MessageReceiverWithStatus* responder = new ResponderThunk(
         weak_factory_.GetWeakPtr(), connector_.task_runner());
-    bool ok = incoming_receiver_->AcceptWithResponder(message, responder);
+    bool ok = incoming_receiver_->AcceptWithResponder(message, responder,
+                                                      error);
     if (!ok)
       delete responder;
     return ok;
@@ -264,6 +275,7 @@ bool Router::HandleMessageInternal(Message* message) {
       auto it = sync_responses_.find(request_id);
       if (it == sync_responses_.end()) {
         DCHECK(testing_mode_);
+        *error = Error::ForUnexpectedResponse(interface_name_, message);
         return false;
       }
       it->second->response.reset(new Message());
@@ -275,16 +287,19 @@ bool Router::HandleMessageInternal(Message* message) {
     auto it = async_responders_.find(request_id);
     if (it == async_responders_.end()) {
       DCHECK(testing_mode_);
+      *error = Error::ForUnexpectedResponse(interface_name_, message);
       return false;
     }
     std::unique_ptr<MessageReceiver> responder = std::move(it->second);
     async_responders_.erase(it);
-    return responder->Accept(message);
+    return responder->Accept(message, error);
   } else {
-    if (!incoming_receiver_)
+    if (!incoming_receiver_) {
+      *error = Error(Error::Type::REQUEST_DROPPED);
       return false;
+    }
 
-    return incoming_receiver_->Accept(message);
+    return incoming_receiver_->Accept(message, error);
   }
 }