iokit/Kernel/IOSyncer.cpp

   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,
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  25  * Please see the License for the specific language governing rights and
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  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /* IOSyncer.cpp created by wgulland on 2000-02-02 */
  31
  32 #include <IOKit/IOLib.h>
  33 #include <IOKit/IOSyncer.h>
  34
  35 OSDefineMetaClassAndStructors(IOSyncer, OSObject)
  36
  37 IOSyncer * IOSyncer::create(bool twoRetains)
  38 {
  39     IOSyncer * me = new IOSyncer;
  40
  41     if (me && !me->init(twoRetains)) {
  42         me->release();
  43         return 0;
  44     }
  45
  46     return me;
  47 }
  48
  49 bool IOSyncer::init(bool twoRetains)
  50 {
  51     if (!OSObject::init())
  52         return false;
  53
  54     if (!(guardLock = IOSimpleLockAlloc()) )
  55         return false;
  56
  57     IOSimpleLockInit(guardLock);
  58
  59     if(twoRetains)
  60         retain();
  61
  62     fResult = kIOReturnSuccess;
  63
  64     reinit();
  65
  66     return true;
  67 }
  68
  69 void IOSyncer::reinit()
  70 {
  71     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  72     threadMustStop = true;
  73     IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  74 }
  75
  76 void IOSyncer::free()
  77 {
  78     // just in case a thread is blocked here:
  79     privateSignal();
  80
  81     if (guardLock != NULL)
  82        IOSimpleLockFree(guardLock);
  83
  84     OSObject::free();
  85 }
  86
  87 IOReturn IOSyncer::wait(bool autoRelease)
  88 {
  89     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  90
  91     if (threadMustStop) {
  92         assert_wait((void *) &threadMustStop, false);
  93         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  94         thread_block(THREAD_CONTINUE_NULL);
  95     }
  96     else
  97         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  98
  99     IOReturn result = fResult;  // Pick up before auto deleting!
 100
 101     if(autoRelease)
 102         release();
 103
 104     return result;
 105 }
 106
 107 void IOSyncer::signal(IOReturn res, bool autoRelease)
 108 {
 109     fResult = res;
 110     privateSignal();
 111     if(autoRelease)
 112         release();
 113 }
 114
 115 void IOSyncer::privateSignal()
 116 {
 117     if (threadMustStop) {
 118          IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
 119          threadMustStop = false;
 120          thread_wakeup_one((void *) &threadMustStop);
 121          IOSimpleLockUnlockEnableInterrupt(guardLock, is);
 122     }
 123 }