iokit/IOKit/IOConditionLock.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1999 Apple Computer, Inc.  All rights reserved.
  29  * Copyright (c) 1994-1996 NeXT Software, Inc.  All rights reserved.
  30  */
  31
  32 #ifndef _IOKIT_IOCONDITIONLOCK_H
  33 #define _IOKIT_IOCONDITIONLOCK_H
  34
  35 #include <libkern/c++/OSObject.h>
  36 #include <IOKit/IOLib.h>
  37 #include <IOKit/system.h>
  38
  39 #include <IOKit/IOLocks.h>
  40
  41 class IOConditionLock : public OSObject
  42 {
  43     OSDeclareDefaultStructors(IOConditionLock)
  44
  45 private:
  46     IOLock *            cond_interlock;         // condition var Simple lock
  47     volatile int        condition;
  48
  49     IOLock *            sleep_interlock;        // sleep lock Simple lock
  50     unsigned char       interruptible;
  51     volatile bool       want_lock;
  52     volatile bool       waiting;
  53
  54 public:
  55     static IOConditionLock *withCondition(int condition, bool inIntr = true);
  56     virtual bool initWithCondition(int condition, bool inIntr = true);
  57     virtual void free();
  58
  59     virtual bool tryLock();     // acquire lock, no waiting
  60     virtual int  lock();        // acquire lock (enter critical section)
  61     virtual void unlock();      // release lock (leave critical section)
  62
  63     virtual bool getInterruptible() const;
  64     virtual int  getCondition() const;
  65     virtual int  setCondition(int condition);
  66
  67     virtual int  lockWhen(int condition); // acquire lock when condition
  68     virtual void unlockWith(int condition); // set condition & release lock
  69 };
  70
  71 #endif /* _IOKIT_IOCONDITIONLOCK_H */