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 NULL; 42 } 43 44 return me; 45 } 46 47 bool 48 IOSyncer::init(bool twoRetains) 49 { 50 if (!OSObject::init()) { 51 return false; 52 } 53 54 if (!(guardLock = IOSimpleLockAlloc())) { 55 return false; 56 } 57 58 IOSimpleLockInit(guardLock); 59 60 if (twoRetains) { 61 retain(); 62 } 63 64 fResult = kIOReturnSuccess; 65 66 reinit(); 67 68 return true; 69 } 70 71 void 72 IOSyncer::reinit() 73 { 74 IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock); 75 threadMustStop = true; 76 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 77 } 78 79 void 80 IOSyncer::free() 81 { 82 // just in case a thread is blocked here: 83 privateSignal(); 84 85 if (guardLock != NULL) { 86 IOSimpleLockFree(guardLock); 87 } 88 89 OSObject::free(); 90 } 91 92 IOReturn 93 IOSyncer::wait(bool autoRelease) 94 { 95 IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock); 96 97 if (threadMustStop) { 98 assert_wait((void *) &threadMustStop, false); 99 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 100 thread_block(THREAD_CONTINUE_NULL); 101 } else { 102 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 103 } 104 105 IOReturn result = fResult; // Pick up before auto deleting! 106 107 if (autoRelease) { 108 release(); 109 } 110 111 return result; 112 } 113 114 void 115 IOSyncer::signal(IOReturn res, bool autoRelease) 116 { 117 fResult = res; 118 privateSignal(); 119 if (autoRelease) { 120 release(); 121 } 122 } 123 124 void 125 IOSyncer::privateSignal() 126 { 127 if (threadMustStop) { 128 IOInterruptState is = IOSimpleLockLockDisableInterrupt(guardLock); 129 threadMustStop = false; 130 thread_wakeup_one((void *) &threadMustStop); 131 IOSimpleLockUnlockEnableInterrupt(guardLock, is); 132 } 133 } 134