/******************************************************************************/ /* */ /* X r d S y s X S L o c k . c c */ /* */ /* (c) 2003 by the Board of Trustees of the Leland Stanford, Jr., University */ /* All Rights Reserved */ /* Produced by Andrew Hanushevsky for Stanford University under contract */ /* DE-AC02-76-SFO0515 with the Department of Energy */ /* */ /* This file is part of the XRootD software suite. */ /* */ /* XRootD is free software: you can redistribute it and/or modify it under */ /* the terms of the GNU Lesser General Public License as published by the */ /* Free Software Foundation, either version 3 of the License, or (at your */ /* option) any later version. */ /* */ /* XRootD is distributed in the hope that it will be useful, but WITHOUT */ /* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */ /* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */ /* License for more details. */ /* */ /* You should have received a copy of the GNU Lesser General Public License */ /* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */ /* COPYING (GPL license). If not, see . */ /* */ /* The copyright holder's institutional names and contributor's names may not */ /* be used to endorse or promote products derived from this software without */ /* specific prior written permission of the institution or contributor. */ /******************************************************************************/ #include "XrdSys/XrdSysHeaders.hh" #include "XrdSys/XrdSysXSLock.hh" /******************************************************************************/ /* D e s t r u c t o r */ /******************************************************************************/ XrdSysXSLock::~XrdSysXSLock() { // Prevent usage while destroying object but make sure no one else is using it // LockContext.Lock(); if (cur_count || shr_wait || exc_wait) {LockContext.UnLock(); abort(); } LockContext.UnLock(); } /******************************************************************************/ /* L o c k */ /******************************************************************************/ void XrdSysXSLock::Lock(const XrdSysXS_Type usage) { // Serialize access to this object // LockContext.Lock(); // This loop continues until we can acquire the resource. We are gauranteed // to eventually acquire it regardless of the unblocking order. // while(cur_count) { // If usage is compatible with current usage get the lock right away // if (usage == xs_Shared && cur_usage == xs_Shared && !exc_wait) break; // Indicate that we are waiting // if (usage == xs_Shared) shr_wait++; else exc_wait++; // Usage is not compatible. We must wait for current lock mode to end // LockContext.UnLock(); if (usage == xs_Shared) WantShr.Wait(); else WantExc.Wait(); LockContext.Lock(); } // We obtained the right to use this object // cur_usage = usage; cur_count++; LockContext.UnLock(); } /******************************************************************************/ /* U n L o c k */ /******************************************************************************/ void XrdSysXSLock::UnLock(const XrdSysXS_Type usage) { // Serialize access to our data // LockContext.Lock(); // Make sure that the lock is currently being used // if (!cur_count) {LockContext.UnLock(); cerr << "XSLock: Attempt to unlock inactive lock." <