iokit/Kernel/IOSyncer.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
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  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* IOSyncer.cpp created by wgulland on 2000-02-02 */
  26
  27 #include <IOKit/IOLib.h>
  28 #include <IOKit/IOSyncer.h>
  29
  30 OSDefineMetaClassAndStructors(IOSyncer, OSObject)
  31
  32 IOSyncer * IOSyncer::create(bool twoRetains)
  33 {
  34     IOSyncer * me = new IOSyncer;
  35
  36     if (me && !me->init(twoRetains)) {
  37         me->release();
  38         return 0;
  39     }
  40
  41     return me;
  42 }
  43
  44 bool IOSyncer::init(bool twoRetains)
  45 {
  46     if (!OSObject::init())
  47         return false;
  48
  49     if (!(guardLock = IOSimpleLockAlloc()) )
  50         return false;
  51
  52     IOSimpleLockInit(guardLock);
  53
  54     if(twoRetains)
  55         retain();
  56
  57     fResult = kIOReturnSuccess;
  58
  59     reinit();
  60
  61     return true;
  62 }
  63
  64 void IOSyncer::reinit()
  65 {
  66     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  67     threadMustStop = true;
  68     IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  69 }
  70
  71 void IOSyncer::free()
  72 {
  73     // just in case a thread is blocked here:
  74     privateSignal();
  75
  76     if (guardLock != NULL)
  77        IOSimpleLockFree(guardLock);
  78
  79     OSObject::free();
  80 }
  81
  82 IOReturn IOSyncer::wait(bool autoRelease = true)
  83 {
  84     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  85
  86     if (threadMustStop) {
  87         assert_wait((void *) &threadMustStop, false);
  88         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  89         thread_block(THREAD_CONTINUE_NULL);
  90     }
  91     else
  92         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  93
  94     IOReturn result = fResult;  // Pick up before auto deleting!
  95
  96     if(autoRelease)
  97         release();
  98
  99     return result;
 100 }
 101
 102 void IOSyncer::signal(IOReturn res = kIOReturnSuccess,
 103                                         bool autoRelease = true)
 104 {
 105     fResult = res;
 106     privateSignal();
 107     if(autoRelease)
 108         release();
 109 }
 110
 111 void IOSyncer::privateSignal()
 112 {
 113     if (threadMustStop) {
 114          IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
 115          threadMustStop = false;
 116          thread_wakeup_one((void *) &threadMustStop);
 117          IOSimpleLockUnlockEnableInterrupt(guardLock, is);
 118     }
 119 }