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git.wh0rd.org - chrome-ext/crftp.git/blob - pnacl/util/queue.h
1 /* Copyright (c) 2012 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.
12 /* This file implements a single-producer/single-consumer queue, using a mutex
13 * and a condition variable.
15 * There are techniques to implement a queue like this without using memory
16 * barriers or locks on x86, but ARM's memory system is different from x86, so
17 * we cannot make the same assumptions about visibility order of writes. Using a
18 * mutex is slower, but also simpler.
20 * We make the assumption that messages are only enqueued on the main thread
21 * and consumed on the worker thread. Because we don't want to block the main
22 * thread, EnqueueMessage will return zero if the message could not be enqueued.
24 * DequeueMessage will block until a message is available using a condition
25 * variable. Again, this may not be as fast as spin-waiting, but will consume
26 * much less CPU (and battery), which is important to consider for ChromeOS
34 void InitializeMessageQueue(void);
35 bool EnqueueMessage(char **argv
, uint32_t argc
);
36 struct q_ele
*DequeueMessage();