iokit/Kernel/IOSyncer.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /* IOSyncer.cpp created by wgulland on 2000-02-02 */
  24
  25 #include <IOKit/IOLib.h>
  26 #include <IOKit/IOSyncer.h>
  27
  28 OSDefineMetaClassAndStructors(IOSyncer, OSObject)
  29
  30 IOSyncer * IOSyncer::create(bool twoRetains)
  31 {
  32     IOSyncer * me = new IOSyncer;
  33
  34     if (me && !me->init(twoRetains)) {
  35         me->release();
  36         return 0;
  37     }
  38
  39     return me;
  40 }
  41
  42 bool IOSyncer::init(bool twoRetains)
  43 {
  44     if (!OSObject::init())
  45         return false;
  46
  47     if (!(guardLock = IOSimpleLockAlloc()) )
  48         return false;
  49
  50     IOSimpleLockInit(guardLock);
  51
  52     if(twoRetains)
  53         retain();
  54
  55     fResult = kIOReturnSuccess;
  56
  57     reinit();
  58
  59     return true;
  60 }
  61
  62 void IOSyncer::reinit()
  63 {
  64     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  65     threadMustStop = true;
  66     IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  67 }
  68
  69 void IOSyncer::free()
  70 {
  71     // just in case a thread is blocked here:
  72     privateSignal();
  73
  74     if (guardLock != NULL)
  75        IOSimpleLockFree(guardLock);
  76
  77     OSObject::free();
  78 }
  79
  80 IOReturn IOSyncer::wait(bool autoRelease)
  81 {
  82     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  83
  84     if (threadMustStop) {
  85         assert_wait((void *) &threadMustStop, false);
  86         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  87         thread_block(THREAD_CONTINUE_NULL);
  88     }
  89     else
  90         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  91
  92     IOReturn result = fResult;  // Pick up before auto deleting!
  93
  94     if(autoRelease)
  95         release();
  96
  97     return result;
  98 }
  99
 100 void IOSyncer::signal(IOReturn res, bool autoRelease)
 101 {
 102     fResult = res;
 103     privateSignal();
 104     if(autoRelease)
 105         release();
 106 }
 107
 108 void IOSyncer::privateSignal()
 109 {
 110     if (threadMustStop) {
 111          IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
 112          threadMustStop = false;
 113          thread_wakeup_one((void *) &threadMustStop);
 114          IOSimpleLockUnlockEnableInterrupt(guardLock, is);
 115     }
 116 }