Mojo: Report bindings validation errors via MojoNotifyBadMessage

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

Index: mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
diff --git a/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc b/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
index 9e32c5af239b3ff45f5d22a64d0a70165f20d5b1..ddac8a58762603cc3cb6b20bd8f285ab34a498c7 100644
--- a/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
+++ b/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
@@ -50,34 +50,34 @@ 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 InterfaceEndpointClient::RaiseError(), because it will raise
         // error from the correct task runner asynchronously.
-        if (endpoint_client_) {
-          endpoint_client_->RaiseError();
-        }
+        if (endpoint_client_)
+          endpoint_client_->RaiseError(std::move(error));
       } else {
         task_runner_->PostTask(
             FROM_HERE,
-            base::Bind(&InterfaceEndpointClient::RaiseError, endpoint_client_));
+            base::Bind(&InterfaceEndpointClient::RaiseError, endpoint_client_,
+                       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 (endpoint_client_)
-      result = endpoint_client_->Accept(message);
+      return endpoint_client_->Accept(message, error);
 
-    return result;
+    *error = Error(Error::Type::RESPONSE_DROPPED);
+    return false;
   }
 
   // MessageReceiverWithStatus implementation:
@@ -123,8 +123,9 @@ InterfaceEndpointClient::HandleIncomingMessageThunk::
     ~HandleIncomingMessageThunk() {}
 
 bool InterfaceEndpointClient::HandleIncomingMessageThunk::Accept(
-    Message* message) {
-  return owner_->HandleValidatedMessage(message);
+    Message* message,
+    Error* error) {
+  return owner_->HandleValidatedMessage(message, error);
 }
 
 // ----------------------------------------------------------------------------
@@ -186,31 +187,36 @@ ScopedInterfaceEndpointHandle InterfaceEndpointClient::PassHandle() {
   return std::move(handle_);
 }
 
-void InterfaceEndpointClient::RaiseError() {
+void InterfaceEndpointClient::RaiseError(Error error) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  handle_.router()->RaiseError();
+  handle_.router()->RaiseError(std::move(error));
 }
 
-bool InterfaceEndpointClient::Accept(Message* message) {
+bool InterfaceEndpointClient::Accept(Message* message, Error* error) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(controller_);
   DCHECK(!message->has_flag(kMessageExpectsResponse));
 
-  if (encountered_error_)
+  if (encountered_error_ || !controller_->SendMessage(message)) {
+    *error = Error(Error::Type::SEND_FAILED);
     return false;
+  }
 
-  return controller_->SendMessage(message);
+  return true;
 }
 
 bool InterfaceEndpointClient::AcceptWithResponder(Message* message,
-                                                  MessageReceiver* responder) {
+                                                  MessageReceiver* responder,
+                                                  Error* error) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(controller_);
   DCHECK(message->has_flag(kMessageExpectsResponse));
 
-  if (encountered_error_)
+  if (encountered_error_) {
+    *error = Error(Error::Type::SEND_FAILED);
     return false;
+  }
 
   // Reserve 0 in case we want it to convey special meaning in the future.
   uint64_t request_id = next_request_id_++;
@@ -220,8 +226,10 @@ bool InterfaceEndpointClient::AcceptWithResponder(Message* message,
   message->set_request_id(request_id);
 
   bool is_sync = message->has_flag(kMessageIsSync);
-  if (!controller_->SendMessage(message))
+  if (!controller_->SendMessage(message)) {
+    *error = Error(Error::Type::SEND_FAILED);
     return false;
+  }
 
   if (!is_sync) {
     // We assume ownership of |responder|.
@@ -243,8 +251,10 @@ bool InterfaceEndpointClient::AcceptWithResponder(Message* message,
     auto iter = sync_responses_.find(request_id);
     DCHECK_EQ(&response_received, iter->second->response_received);
     if (response_received) {
+      Error send_response_error;
       std::unique_ptr<Message> response = std::move(iter->second->response);
-      ignore_result(sync_responder->Accept(response.get()));
+      ignore_result(sync_responder->Accept(response.get(),
+                                           &send_response_error));
     }
     sync_responses_.erase(iter);
   }
@@ -253,10 +263,11 @@ bool InterfaceEndpointClient::AcceptWithResponder(Message* message,
   return true;
 }
 
-bool InterfaceEndpointClient::HandleIncomingMessage(Message* message) {
+bool InterfaceEndpointClient::HandleIncomingMessage(Message* message,
+                                                    Error* error) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  return payload_validator_->Accept(message);
+  return payload_validator_->Accept(message, error);
 }
 
 void InterfaceEndpointClient::NotifyError() {
@@ -268,16 +279,20 @@ void InterfaceEndpointClient::NotifyError() {
   error_handler_.Run();
 }
 
-bool InterfaceEndpointClient::HandleValidatedMessage(Message* message) {
+bool InterfaceEndpointClient::HandleValidatedMessage(Message* message,
+                                                     Error* error) {
   DCHECK_EQ(handle_.id(), message->interface_id());
 
   if (message->has_flag(kMessageExpectsResponse)) {
-    if (!incoming_receiver_)
+    if (!incoming_receiver_) {
+      *error = Error(Error::Type::REQUEST_DROPPED);
       return false;
+    }
 
     MessageReceiverWithStatus* responder =
         new ResponderThunk(weak_ptr_factory_.GetWeakPtr(), task_runner_);
-    bool ok = incoming_receiver_->AcceptWithResponder(message, responder);
+    bool ok = incoming_receiver_->AcceptWithResponder(message, responder,
+                                                      error);
     if (!ok)
       delete responder;
     return ok;
@@ -286,8 +301,10 @@ bool InterfaceEndpointClient::HandleValidatedMessage(Message* message) {
 
     if (message->has_flag(kMessageIsSync)) {
       auto it = sync_responses_.find(request_id);
-      if (it == sync_responses_.end())
+      if (it == sync_responses_.end()) {
+        *error = Error::ForUnexpectedResponse(interface_name_, message);
         return false;
+      }
       it->second->response.reset(new Message());
       message->MoveTo(it->second->response.get());
       *it->second->response_received = true;
@@ -295,16 +312,20 @@ bool InterfaceEndpointClient::HandleValidatedMessage(Message* message) {
     }
 
     auto it = async_responders_.find(request_id);
-    if (it == async_responders_.end())
+    if (it == async_responders_.end()) {
+      *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);
   }
 }