1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_MESSAGE_INTERNAL_H_
6 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_MESSAGE_INTERNAL_H_
7 
8 #include <stdint.h>
9 
10 #include "mojo/public/cpp/bindings/lib/bindings_internal.h"
11 
12 namespace mojo {
13 namespace internal {
14 
15 #pragma pack(push, 1)
16 
17 struct MessageHeader : internal::StructHeader {
18   // Interface ID for identifying multiple interfaces running on the same
19   // message pipe.
20   uint32_t interface_id;
21   // Message name, which is scoped to the interface that the message belongs to.
22   uint32_t name;
23   // 0 or either of the enum values defined above.
24   uint32_t flags;
25   // Unused padding to make the struct size a multiple of 8 bytes.
26   uint32_t padding;
27 };
28 static_assert(sizeof(MessageHeader) == 24, "Bad sizeof(MessageHeader)");
29 
30 struct MessageHeaderWithRequestID : MessageHeader {
31   // Only used if either kFlagExpectsResponse or kFlagIsResponse is set in
32   // order to match responses with corresponding requests.
33   uint64_t request_id;
34 };
35 static_assert(sizeof(MessageHeaderWithRequestID) == 32,
36               "Bad sizeof(MessageHeaderWithRequestID)");
37 
38 #pragma pack(pop)
39 
40 }  // namespace internal
41 }  // namespace mojo
42 
43 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_MESSAGE_INTERNAL_H_
44