gold/workqueue-internal.h

   1 // workqueue-internal.h -- internal work queue header for gold   -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008 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() = 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();
  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)