iokit/IOKit/IOConditionLock.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /* Copyright (c) 1999 Apple Computer, Inc.  All rights reserved.
  31  * Copyright (c) 1994-1996 NeXT Software, Inc.  All rights reserved.
  32  */
  33
  34 #ifndef _IOKIT_IOCONDITIONLOCK_H
  35 #define _IOKIT_IOCONDITIONLOCK_H
  36
  37 #include <libkern/c++/OSObject.h>
  38 #include <IOKit/IOLib.h>
  39 #include <IOKit/system.h>
  40
  41 #include <IOKit/IOLocks.h>
  42
  43 class IOConditionLock : public OSObject
  44 {
  45     OSDeclareDefaultStructors(IOConditionLock)
  46
  47 private:
  48     IOLock *            cond_interlock;         // condition var Simple lock
  49     volatile int        condition;
  50
  51     IOLock *            sleep_interlock;        // sleep lock Simple lock
  52     unsigned char       interruptible;
  53     volatile bool       want_lock;
  54     volatile bool       waiting;
  55
  56 public:
  57     static IOConditionLock *withCondition(int condition, bool inIntr = true);
  58     virtual bool initWithCondition(int condition, bool inIntr = true);
  59     virtual void free();
  60
  61     virtual bool tryLock();     // acquire lock, no waiting
  62     virtual int  lock();        // acquire lock (enter critical section)
  63     virtual void unlock();      // release lock (leave critical section)
  64
  65     virtual bool getInterruptible() const;
  66     virtual int  getCondition() const;
  67     virtual int  setCondition(int condition);
  68
  69     virtual int  lockWhen(int condition); // acquire lock when condition
  70     virtual void unlockWith(int condition); // set condition & release lock
  71 };
  72
  73 #endif /* _IOKIT_IOCONDITIONLOCK_H */