1// Copyright (c) 2011 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 CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_
6#define CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_
7
8#include "content/common/one_writer_seqlock.h"
9#include "third_party/WebKit/public/platform/WebGamepads.h"
10
11namespace content {
12
13/*
14
15This structure is stored in shared memory that's shared between the browser
16which does the hardware polling, and the various consumers of the gamepad
17state (renderers and NaCl plugins). The performance characteristics are that
18we want low latency (so would like to avoid explicit communication via IPC
19between producer and consumer) and relatively large data size.
20
21Writer and reader operate on the same buffer assuming contention is low, and
22contention is detected by using the associated SeqLock.
23
24*/
25
26struct GamepadHardwareBuffer {
27  // FIXME: Use the generic SharedMemorySeqLockBuffer<blink::WebGamepads>.
28  OneWriterSeqLock sequence;
29  blink::WebGamepads buffer;
30};
31
32}  // namespace content
33
34#endif  // CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_
35