NCBI C++ Toolkit Cross Reference

C++/src/util/thread_pool_old.cpp

  1 /*  $Id: thread_pool_old.cpp 122643 2008-03-24 13:44:29Z ivanovp $
  2 * ===========================================================================
  3 *
  4 *                            PUBLIC DOMAIN NOTICE
  5 *               National Center for Biotechnology Information
  6 *
  7 *  This software/database is a "United States Government Work" under the
  8 *  terms of the United States Copyright Act.  It was written as part of
  9 *  the author's official duties as a United States Government employee and
 10 *  thus cannot be copyrighted.  This software/database is freely available
 11 *  to the public for use. The National Library of Medicine and the U.S.
 12 *  Government have not placed any restriction on its use or reproduction.
 13 *
 14 *  Although all reasonable efforts have been taken to ensure the accuracy
 15 *  and reliability of the software and data, the NLM and the U.S.
 16 *  Government do not and cannot warrant the performance or results that
 17 *  may be obtained by using this software or data. The NLM and the U.S.
 18 *  Government disclaim all warranties, express or implied, including
 19 *  warranties of performance, merchantability or fitness for any particular
 20 *  purpose.
 21 *
 22 *  Please cite the author in any work or product based on this material.
 23 *
 24 * ===========================================================================
 25 *
 26 * Author:  Aaron Ucko
 27 *
 28 * File Description:
 29 *   Pools of generic request-handling threads.
 30 */
 31 
 32 #include <ncbi_pch.hpp>
 33 #include <util/thread_pool.hpp>
 34 #include <corelib/ncbi_system.hpp>
 35 #include <algorithm>
 36 
 37 BEGIN_NCBI_SCOPE
 38 
 39 
 40 class CFatalRequest : public CStdRequest
 41 {
 42 protected:
 43     void Process(void) { CThread::Exit(0); } // Kill the current thread
 44 };
 45 
 46 
 47 void CStdPoolOfThreads::KillAllThreads(bool wait)
 48 {
 49     TACValue n, old_max;
 50     {{
 51         CMutexGuard guard(m_Mutex);
 52         old_max = m_MaxThreads;
 53         m_MaxThreads = 0;  // Forbid spawning new threads
 54         n = m_ThreadCount.Get(); // Capture for use without mutex
 55     }}
 56 
 57     CRef<CStdRequest> poison(new CFatalRequest);
 58 
 59     for (TACValue i = 0;  i < n;  ) {
 60         try {
 61             WaitForRoom();
 62             AcceptRequest(poison);
 63             ++i;
 64         } catch (CBlockingQueueException&) { // guard against races
 65             continue;
 66         }
 67     }
 68     NON_CONST_ITERATE(TThreads, it, m_Threads) {
 69         if (wait) {
 70             (*it)->Join();
 71         } else {
 72             (*it)->Detach();
 73         }
 74     }
 75     m_Threads.clear();
 76     {{
 77         CMutexGuard guard(m_Mutex);
 78         m_MaxThreads = old_max;
 79     }}
 80 }
 81 
 82 
 83 void CStdPoolOfThreads::Register(TThread& thread)
 84 {
 85     CMutexGuard guard(m_Mutex);
 86     if (m_MaxThreads > 0) {
 87         m_Threads.push_back(CRef<TThread>(&thread));
 88     }
 89 }
 90 
 91 void CStdPoolOfThreads::UnRegister(TThread& thread)
 92 {
 93     CMutexGuard guard(m_Mutex);
 94     if (m_MaxThreads > 0) {
 95         TThreads::iterator it = find(m_Threads.begin(), m_Threads.end(),
 96                                      CRef<TThread>(&thread));
 97         if (it != m_Threads.end()) {
 98             (*it)->Detach();
 99             m_Threads.erase(it);
100         }
101     }
102 }
103 
104 CStdPoolOfThreads::~CStdPoolOfThreads()
105 {
106     try {
107         KillAllThreads(false);
108     } catch(...) {}    // Just to be sure that we will not throw from the destructor.
109 }
110 
111 END_NCBI_SCOPE
112
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