Mojo bindings: merge the control messages of sending disconnect reason and notifying endpoint close…

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

Index: mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.cc
diff --git a/mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.cc b/mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.cc
index f54c3f749c437165efeeab20f1a3fad684f474e0..1dffcb3f1eed05af373da344b7d83a4d409c08e8 100644
--- a/mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.cc
+++ b/mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.cc
@@ -32,14 +32,15 @@ ScopedInterfaceEndpointHandle& ScopedInterfaceEndpointHandle::operator=(
 }
 
 void ScopedInterfaceEndpointHandle::reset() {
-  if (!IsValidInterfaceId(id_))
-    return;
-
-  group_controller_->CloseEndpointHandle(id_, is_local_);
+  ResetInternal(base::nullopt);
+}
 
-  id_ = kInvalidInterfaceId;
-  is_local_ = true;
-  group_controller_ = nullptr;
+void ScopedInterfaceEndpointHandle::ResetWithReason(
+    uint32_t custom_reason,
+    const std::string& description) {
+  base::Optional<DisconnectReason> reason;
+  reason.emplace(custom_reason, description);
+  ResetInternal(reason);

[dcheng, 2017/01/23 23:20:22]

FWIW, here and a couple other places

ResetInternal(DisconnectReason(custom_reason, description))

would also work and should save a copy.

[yzshen1, 2017/01/23 23:30:09]

I think the original code doesn't copy either. Have I missed anything?

But the change you proposed is more concise. I could make such a change in my
next CL.

[dcheng, 2017/01/24 03:39:21]

Ah, you're right: my comment is only true if |reason| is passed by value instead
of const ref. Sorry!

 }
 
 void ScopedInterfaceEndpointHandle::swap(ScopedInterfaceEndpointHandle& other) {
@@ -69,4 +70,16 @@ ScopedInterfaceEndpointHandle::ScopedInterfaceEndpointHandle(
   DCHECK(!IsValidInterfaceId(id) || group_controller_);
 }
 
+void ScopedInterfaceEndpointHandle::ResetInternal(
+    const base::Optional<DisconnectReason>& reason) {
+  if (!IsValidInterfaceId(id_))
+    return;
+
+  group_controller_->CloseEndpointHandle(id_, is_local_, reason);
+
+  id_ = kInvalidInterfaceId;
+  is_local_ = true;
+  group_controller_ = nullptr;
+}
+
 }  // namespace mojo