iokit/Kernel/IOSyncer.cpp

   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 /* IOSyncer.cpp created by wgulland on 2000-02-02 */
  23
  24 #include <IOKit/IOLib.h>
  25 #include <IOKit/IOSyncer.h>
  26
  27 OSDefineMetaClassAndStructors(IOSyncer, OSObject)
  28
  29 IOSyncer * IOSyncer::create(bool twoRetains)
  30 {
  31     IOSyncer * me = new IOSyncer;
  32
  33     if (me && !me->init(twoRetains)) {
  34         me->release();
  35         return 0;
  36     }
  37
  38     return me;
  39 }
  40
  41 bool IOSyncer::init(bool twoRetains)
  42 {
  43     if (!OSObject::init())
  44         return false;
  45
  46     if (!(guardLock = IOSimpleLockAlloc()) )
  47         return false;
  48
  49     IOSimpleLockInit(guardLock);
  50
  51     if(twoRetains)
  52         retain();
  53
  54     fResult = kIOReturnSuccess;
  55
  56     reinit();
  57
  58     return true;
  59 }
  60
  61 void IOSyncer::reinit()
  62 {
  63     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  64     threadMustStop = true;
  65     IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  66 }
  67
  68 void IOSyncer::free()
  69 {
  70     // just in case a thread is blocked here:
  71     privateSignal();
  72
  73     if (guardLock != NULL)
  74        IOSimpleLockFree(guardLock);
  75
  76     OSObject::free();
  77 }
  78
  79 IOReturn IOSyncer::wait(bool autoRelease)
  80 {
  81     IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
  82
  83     if (threadMustStop) {
  84         assert_wait((void *) &threadMustStop, false);
  85         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  86         thread_block(THREAD_CONTINUE_NULL);
  87     }
  88     else
  89         IOSimpleLockUnlockEnableInterrupt(guardLock, is);
  90
  91     IOReturn result = fResult;  // Pick up before auto deleting!
  92
  93     if(autoRelease)
  94         release();
  95
  96     return result;
  97 }
  98
  99 void IOSyncer::signal(IOReturn res, bool autoRelease)
 100 {
 101     fResult = res;
 102     privateSignal();
 103     if(autoRelease)
 104         release();
 105 }
 106
 107 void IOSyncer::privateSignal()
 108 {
 109     if (threadMustStop) {
 110          IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock);
 111          threadMustStop = false;
 112          thread_wakeup_one((void *) &threadMustStop);
 113          IOSimpleLockUnlockEnableInterrupt(guardLock, is);
 114     }
 115 }