1  // workqueue-internal.h -- internal work queue header for gold   -*- C++ -*-
       2  
       3  // Copyright (C) 2006-2023 Free Software Foundation, Inc.
       4  // Written by Ian Lance Taylor <iant@google.com>.
       5  
       6  // This file is part of gold.
       7  
       8  // This program is free software; you can redistribute it and/or modify
       9  // it under the terms of the GNU General Public License as published by
      10  // the Free Software Foundation; either version 3 of the License, or
      11  // (at your option) any later version.
      12  
      13  // This program is distributed in the hope that it will be useful,
      14  // but WITHOUT ANY WARRANTY; without even the implied warranty of
      15  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      16  // GNU General Public License for more details.
      17  
      18  // You should have received a copy of the GNU General Public License
      19  // along with this program; if not, write to the Free Software
      20  // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
      21  // MA 02110-1301, USA.
      22  
      23  #ifndef GOLD_WORKQUEUE_INTERNAL_H
      24  #define GOLD_WORKQUEUE_INTERNAL_H
      25  
      26  #include <queue>
      27  #include <csignal>
      28  
      29  #include "gold-threads.h"
      30  #include "workqueue.h"
      31  
      32  // This is an internal header file for different gold workqueue
      33  // implementations.
      34  
      35  namespace gold
      36  {
      37  
      38  class Workqueue_thread;
      39  
      40  // The Workqueue_threader abstract class.  This is the interface used
      41  // by the general workqueue code to manage threads.
      42  
      43  class Workqueue_threader
      44  {
      45   public:
      46    Workqueue_threader(Workqueue* workqueue)
      47      : workqueue_(workqueue)
      48    { }
      49    virtual ~Workqueue_threader()
      50    { }
      51  
      52    // Set the number of threads to use.  This is ignored when not using
      53    // threads.
      54    virtual void
      55    set_thread_count(int) = 0;
      56  
      57    // Return whether to cancel the current thread.
      58    virtual bool
      59    should_cancel_thread(int thread_number) = 0;
      60  
      61   protected:
      62    // Get the Workqueue.
      63    Workqueue*
      64    get_workqueue()
      65    { return this->workqueue_; }
      66  
      67   private:
      68    // The Workqueue.
      69    Workqueue* workqueue_;
      70  };
      71  
      72  // The threaded instantiation of Workqueue_threader.
      73  
      74  class Workqueue_threader_threadpool : public Workqueue_threader
      75  {
      76   public:
      77    Workqueue_threader_threadpool(Workqueue*);
      78  
      79    ~Workqueue_threader_threadpool();
      80  
      81    // Set the thread count.
      82    void
      83    set_thread_count(int);
      84  
      85    // Return whether to cancel a thread.
      86    bool
      87    should_cancel_thread(int thread_number);
      88  
      89    // Process all tasks.  This keeps running until told to cancel.
      90    void
      91    process(int thread_number)
      92    { this->get_workqueue()->process(thread_number); }
      93  
      94   private:
      95    // This is set if we need to check the thread count.
      96    volatile sig_atomic_t check_thread_count_;
      97  
      98    // Lock for the remaining members.
      99    Lock lock_;
     100    // The number of threads we want to create.  This is set to zero
     101    // when all threads should exit.
     102    int desired_thread_count_;
     103    // The number of threads currently running.
     104    int threads_;
     105  };
     106  
     107  } // End namespace gold.
     108  
     109  #endif // !defined(GOLD_WORKQUEUE_INTERNAL_H)