1 /* 2 Open Tracker License 3 4 Terms and Conditions 5 6 Copyright (c) 1991-2000, Be Incorporated. All rights reserved. 7 8 Permission is hereby granted, free of charge, to any person obtaining a copy of 9 this software and associated documentation files (the "Software"), to deal in 10 the Software without restriction, including without limitation the rights to 11 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 12 of the Software, and to permit persons to whom the Software is furnished to do 13 so, subject to the following conditions: 14 15 The above copyright notice and this permission notice applies to all licensees 16 and shall be included in all copies or substantial portions of the Software. 17 18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF TITLE, MERCHANTABILITY, 20 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 21 BE INCORPORATED BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN 22 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION 23 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 24 25 Except as contained in this notice, the name of Be Incorporated shall not be 26 used in advertising or otherwise to promote the sale, use or other dealings in 27 this Software without prior written authorization from Be Incorporated. 28 29 Tracker(TM), Be(R), BeOS(R), and BeIA(TM) are trademarks or registered trademarks 30 of Be Incorporated in the United States and other countries. Other brand product 31 names are registered trademarks or trademarks of their respective holders. 32 All rights reserved. 33 */ 34 35 #ifndef _AUTO_LOCK_H 36 #define _AUTO_LOCK_H 37 38 template<class T> 39 class AutoLock 40 { 41 42 // exception safe locking mechanism, allocate on stack and have 43 // destructor unlock for you whenever the lock goes out of scope 44 45 public: 46 AutoLock(T *lock, bool lockNow = true) 47 // use <lockLater> for lazy locking 48 : fLock(lock), 49 fHasLock(false) 50 { 51 if (lockNow) 52 fHasLock = fLock->Lock(); 53 } 54 55 AutoLock(T &lock, bool lockNow = true) 56 : fLock(&lock), 57 fHasLock(false) 58 { 59 if (lockNow) 60 fHasLock = fLock->Lock(); 61 } 62 63 ~AutoLock() 64 { 65 if (fHasLock) 66 fLock->Unlock(); 67 } 68 69 bool operator!() const 70 { return !fHasLock; } 71 72 bool IsLocked() const 73 { return fHasLock; } 74 75 // explicit Lock/Unlock calls are only used in special cases 76 // for unlocking before lock goes out of scope and successive 77 // re-locking 78 // usually constructor/destructor locks/unlocks are sufficient 79 void Unlock() 80 { 81 if (fHasLock) { 82 fLock->Unlock(); 83 fHasLock = false; 84 } 85 } 86 87 bool Lock() 88 { 89 if (!fHasLock) 90 fHasLock = fLock->Lock(); 91 92 return fHasLock; 93 } 94 95 // convenience call used when passing the AutoLock and the locked object 96 // around 97 T *LockedItem() const 98 { return fLock; } 99 100 private: 101 T *fLock; 102 bool fHasLock; 103 }; 104 105 #endif 106