1 /* 2 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_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. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 /* IOSyncer.cpp created by wgulland on 2000-02-02 */ 29 30 #include <IOKit/IOLib.h> 31 #include <IOKit/IOSyncer.h> 32 33 OSDefineMetaClassAndStructors(IOSyncer, OSObject) 34 35 IOSyncer * IOSyncer::create(bool twoRetains) 36 { 37 IOSyncer * me = new IOSyncer; 38 39 if (me && !me->init(twoRetains)) { 40 me->release(); 41 return 0; 42 } 43 44 return me; 45 } 46 47 bool IOSyncer::init(bool twoRetains) 48 { 49 if (!OSObject::init()) 50 return false; 51 52 if (!(guardLock = IOSimpleLockAlloc()) ) 53 return false; 54 55 IOSimpleLockInit(guardLock); 56 57 if(twoRetains) 58 retain(); 59 60 fResult = kIOReturnSuccess; 61 62 reinit(); 63 64 return true; 65 } 66 67 void IOSyncer::reinit() 68 { 69 IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock); 70 threadMustStop = true; 71 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 72 } 73 74 void IOSyncer::free() 75 { 76 // just in case a thread is blocked here: 77 privateSignal(); 78 79 if (guardLock != NULL) 80 IOSimpleLockFree(guardLock); 81 82 OSObject::free(); 83 } 84 85 IOReturn IOSyncer::wait(bool autoRelease) 86 { 87 IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock); 88 89 if (threadMustStop) { 90 assert_wait((void *) &threadMustStop, false); 91 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 92 thread_block(THREAD_CONTINUE_NULL); 93 } 94 else 95 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 96 97 IOReturn result = fResult; // Pick up before auto deleting! 98 99 if(autoRelease) 100 release(); 101 102 return result; 103 } 104 105 void IOSyncer::signal(IOReturn res, bool autoRelease) 106 { 107 fResult = res; 108 privateSignal(); 109 if(autoRelease) 110 release(); 111 } 112 113 void IOSyncer::privateSignal() 114 { 115 if (threadMustStop) { 116 IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock); 117 threadMustStop = false; 118 thread_wakeup_one((void *) &threadMustStop); 119 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 120 } 121 } 122