Sync from internal Google development.

Many improvements, too many to mention.  One significant
perf regression warrants investigation:

omitfp.parsetoproto2_googlemessage1.upb_jit: 343 -> 252 (-26.53)
plain.parsetoproto2_googlemessage1.upb_jit: 334 -> 251 (-24.85)

25% regression for this benchmark is bad, but since I don't think
there's any fundamental design issue that caused it I'm going to
go ahead with the commit anyway.  Can investigate and fix later.

Other benchmarks were neutral or showed slight improvement.

1 files changed, 39 insertions, 0 deletions

diff --git a/bindings/cpp/upb/handlers.cc b/bindings/cpp/upb/handlers.cc
new file mode 100644
index 0000000..c96a74e
--- /dev/null
+++ b/bindings/cpp/upb/handlers.cc
@@ -0,0 +1,39 @@
+//
+// upb - a minimalist implementation of protocol buffers.
+//
+// Copyright (c) 2011 Google Inc.  See LICENSE for details.
+// Author: Josh Haberman <jhaberman@gmail.com>
+
+#include "handlers.hpp"
+
+#include "def.hpp"
+
+namespace upb {
+
+namespace {
+
+void MessageCallbackWrapper(
+    void* closure, upb_mhandlers* mh, const upb_msgdef* m) {
+  Handlers::MessageRegistrationVisitor* visitor =
+      static_cast<Handlers::MessageRegistrationVisitor*>(closure);
+  visitor->OnMessage(static_cast<MessageHandlers*>(mh),
+                     static_cast<const MessageDef*>(m));
+}
+
+void FieldCallbackWrapper(
+    void* closure, upb_fhandlers* fh, const upb_fielddef* f) {
+  Handlers::MessageRegistrationVisitor* visitor =
+      static_cast<Handlers::MessageRegistrationVisitor*>(closure);
+  visitor->OnField(static_cast<FieldHandlers*>(fh),
+                   static_cast<const FieldDef*>(f));
+}
+}  // namepace
+
+MessageHandlers* Handlers::RegisterMessageDef(
+    const MessageDef& m, Handlers::MessageRegistrationVisitor* visitor) {
+  upb_mhandlers* mh = upb_handlers_regmsgdef(
+      this, &m, &MessageCallbackWrapper, &FieldCallbackWrapper, &visitor);
+  return static_cast<MessageHandlers*>(mh);
+}
+
+}  // namespace upb