1 files changed, 35 insertions, 0 deletions
diff --git a/mojo/public/cpp/bindings/interface_id.h b/mojo/public/cpp/bindings/interface_id.h
new file mode 100644
index 0000000000..53475d6f78
--- /dev/null
+++ b/mojo/public/cpp/bindings/interface_id.h
@@ -0,0 +1,35 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ID_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ID_H_
+
+#include <stdint.h>
+
+namespace mojo {
+
+// The size of the type matters because it is directly used in messages.
+using InterfaceId = uint32_t;
+
+// IDs of associated interface can be generated at both sides of the message
+// pipe. In order to avoid collision, the highest bit is used as namespace bit:
+// at the side where the client-side of the master interface lives, IDs are
+// generated with the namespace bit set to 1; at the opposite side IDs are
+// generated with the namespace bit set to 0.
+const uint32_t kInterfaceIdNamespaceMask = 0x80000000;
+
+const InterfaceId kMasterInterfaceId = 0x00000000;
+const InterfaceId kInvalidInterfaceId = 0xFFFFFFFF;
+
+inline bool IsMasterInterfaceId(InterfaceId id) {
+  return id == kMasterInterfaceId;
+}
+
+inline bool IsValidInterfaceId(InterfaceId id) {
+  return id != kInvalidInterfaceId;
+}
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ID_H_