iokit/IOKit/IOConditionLock.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1999 Apple Computer, Inc.  All rights reserved.
  23  * Copyright (c) 1994-1996 NeXT Software, Inc.  All rights reserved.
  24  */
  25
  26 #ifndef _IOKIT_IOCONDITIONLOCK_H
  27 #define _IOKIT_IOCONDITIONLOCK_H
  28
  29 #include <libkern/c++/OSObject.h>
  30 #include <IOKit/IOLib.h>
  31 #include <IOKit/system.h>
  32
  33 #include <IOKit/IOLocks.h>
  34
  35 class IOConditionLock : public OSObject
  36 {
  37     OSDeclareDefaultStructors(IOConditionLock)
  38
  39 private:
  40     IOLock *            cond_interlock;         // condition var Simple lock
  41     volatile int        condition;
  42
  43     IOLock *            sleep_interlock;        // sleep lock Simple lock
  44     unsigned char       interruptible;
  45     volatile bool       want_lock;
  46     volatile bool       waiting;
  47
  48 public:
  49     static IOConditionLock *withCondition(int condition, bool inIntr = true);
  50     virtual bool initWithCondition(int condition, bool inIntr = true);
  51     virtual void free();
  52
  53     virtual bool tryLock();     // acquire lock, no waiting
  54     virtual int  lock();        // acquire lock (enter critical section)
  55     virtual void unlock();      // release lock (leave critical section)
  56
  57     virtual bool getInterruptible() const;
  58     virtual int  getCondition() const;
  59     virtual int  setCondition(int condition);
  60
  61     virtual int  lockWhen(int condition); // acquire lock when condition
  62     virtual void unlockWith(int condition); // set condition & release lock
  63 };
  64
  65 #endif /* _IOKIT_IOCONDITIONLOCK_H */