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