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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_ | 5 #ifndef CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_ |
6 #define CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_ | 6 #define CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_ |
7 | 7 |
8 #include "content/common/one_writer_seqlock.h" | 8 #include "components/shared_memory_seqlock/one_writer_seqlock.h" |
9 #include "third_party/WebKit/public/platform/WebGamepads.h" | 9 #include "third_party/WebKit/public/platform/WebGamepads.h" |
10 | 10 |
11 namespace content { | 11 namespace content { |
12 | 12 |
13 /* | 13 /* |
14 | 14 |
15 This structure is stored in shared memory that's shared between the browser | 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 | 16 which does the hardware polling, and the various consumers of the gamepad |
17 state (renderers and NaCl plugins). The performance characteristics are that | 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 | 18 we want low latency (so would like to avoid explicit communication via IPC |
19 between producer and consumer) and relatively large data size. | 19 between producer and consumer) and relatively large data size. |
20 | 20 |
21 Writer and reader operate on the same buffer assuming contention is low, and | 21 Writer and reader operate on the same buffer assuming contention is low, and |
22 contention is detected by using the associated SeqLock. | 22 contention is detected by using the associated SeqLock. |
23 | 23 |
24 */ | 24 */ |
25 | 25 |
26 struct GamepadHardwareBuffer { | 26 struct GamepadHardwareBuffer { |
27 // FIXME: Use the generic SharedMemorySeqLockBuffer<blink::WebGamepads>. | 27 // FIXME: Use the generic SharedMemorySeqLockBuffer<blink::WebGamepads>. |
28 OneWriterSeqLock sequence; | 28 shared_memory_seqlock::OneWriterSeqLock sequence; |
29 blink::WebGamepads buffer; | 29 blink::WebGamepads buffer; |
30 }; | 30 }; |
31 | 31 |
32 } // namespace content | 32 } // namespace content |
33 | 33 |
34 #endif // CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_ | 34 #endif // CONTENT_COMMON_GAMEPAD_HARDWARE_BUFFER_H_ |
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