libcamera: include/libcamera/base/semaphore.h Source File

libcamera v0.7.0 Supporting cameras in Linux since 2019

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semaphore.h
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2/*
3 * Copyright (C) 2019, Google Inc.
4 *
5 * General-purpose counting semaphore
6 */
7
8#pragma once
9
10#include <libcamera/base/private.h>
11
12#include <libcamera/base/mutex.h>
13
14namespace libcamera {
15
16 class Semaphore
17{
18public:
19 Semaphore(unsigned int n = 0);
20
21 unsigned int available() LIBCAMERA_TSA_EXCLUDES(mutex_);
22 void acquire(unsigned int n = 1) LIBCAMERA_TSA_EXCLUDES(mutex_);
23 bool tryAcquire(unsigned int n = 1) LIBCAMERA_TSA_EXCLUDES(mutex_);
24 void release(unsigned int n = 1) LIBCAMERA_TSA_EXCLUDES(mutex_);
25
26private:
27 Mutex mutex_;
28 ConditionVariable cv_;
29 unsigned int available_ LIBCAMERA_TSA_GUARDED_BY(mutex_);
30};
31
32} /* namespace libcamera */
libcamera::ConditionVariable
std::condition_variable wrapper integrating with MutexLocker
Definition mutex.h:122
libcamera::Mutex
std::mutex wrapper with clang thread safety annotation
Definition mutex.h:114
libcamera::Semaphore::release
void release(unsigned int n=1) LIBCAMERA_TSA_EXCLUDES(mutex_)
Release n resources.
Definition semaphore.cpp:94
libcamera::Semaphore::acquire
void acquire(unsigned int n=1) LIBCAMERA_TSA_EXCLUDES(mutex_)
Acquire n resources.
Definition semaphore.cpp:56
libcamera::Semaphore::available
unsigned int available() LIBCAMERA_TSA_EXCLUDES(mutex_)
Retrieve the number of available resources.
Definition semaphore.cpp:42
libcamera::Semaphore::Semaphore
Semaphore(unsigned int n=0)
Construct a semaphore with n resources.
Definition semaphore.cpp:33
libcamera::Semaphore::tryAcquire
bool tryAcquire(unsigned int n=1) LIBCAMERA_TSA_EXCLUDES(mutex_)
Try to acquire n resources without blocking.
Definition semaphore.cpp:76
mutex.h
Mutex classes with clang thread safety annotation.
libcamera
Top-level libcamera namespace.
Definition backtrace.h:17