Swiftgram/Source/Details/ASRecursiveUnfairLock.h
Adlai Holler dbe469a94a
Standardize "extern" decls on AS_EXTERN (#972)
* Standardize "extern" decls on AS_EXTERN

* Rebase & remove from implementation files
2018-06-18 15:53:34 -07:00

57 lines
1.6 KiB
Objective-C

//
// ASRecursiveUnfairLock.h
// Texture
//
// Copyright (c) 2018-present, Pinterest, Inc. All rights reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
#import <Foundation/Foundation.h>
#import <AsyncDisplayKit/ASBaseDefines.h>
#import <pthread/pthread.h>
#import <os/lock.h>
// Don't import C-only header if we're in a C++ file
#ifndef __cplusplus
#import <stdatomic.h>
#endif
// Note: We don't use ATOMIC_VAR_INIT here because C++ compilers don't like it,
// and it literally does absolutely nothing.
#define AS_RECURSIVE_UNFAIR_LOCK_INIT ((ASRecursiveUnfairLock){ OS_UNFAIR_LOCK_INIT, NULL, 0})
NS_ASSUME_NONNULL_BEGIN
OS_UNFAIR_LOCK_AVAILABILITY
typedef struct {
os_unfair_lock _lock;
_Atomic(pthread_t) _thread; // Write-protected by lock
int _count; // Protected by lock
} ASRecursiveUnfairLock;
/**
* Lock, blocking if needed.
*/
AS_EXTERN OS_UNFAIR_LOCK_AVAILABILITY
void ASRecursiveUnfairLockLock(ASRecursiveUnfairLock *l);
/**
* Try to lock without blocking. Returns whether we took the lock.
*/
AS_EXTERN OS_UNFAIR_LOCK_AVAILABILITY
BOOL ASRecursiveUnfairLockTryLock(ASRecursiveUnfairLock *l);
/**
* Unlock. Calling this on a thread that does not own
* the lock will result in an assertion failure, and undefined
* behavior if foundation assertions are disabled.
*/
AS_EXTERN OS_UNFAIR_LOCK_AVAILABILITY
void ASRecursiveUnfairLockUnlock(ASRecursiveUnfairLock *l);
NS_ASSUME_NONNULL_END