src/support/forkedcallqueue.C

   1 /**
   2  * \file forkedcallqueue.C
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Alfredo Braunstein (based on an idea from Angus Leeming)
   7  *
   8  * Full author contact details are available in file CREDITS
   9  */
  10
  11 #include "forkedcallqueue.h"
  12
  13 #include "debug.h"
  14
  15 #include <boost/bind.hpp>
  16 #include <boost/signals/signal2.hpp>
  17
  18 using std::endl;
  19 using std::queue;
  20
  21 ForkedCallQueue & ForkedCallQueue::get()
  22 {
  23         static ForkedCallQueue singleton;
  24         return singleton;
  25 }
  26
  27
  28 Forkedcall::SignalTypePtr ForkedCallQueue::add(string const & process)
  29 {
  30         Forkedcall::SignalTypePtr ptr;
  31         ptr.reset(new Forkedcall::SignalType);
  32         callQueue_.push(Process(process, ptr));
  33         if (!running_) {
  34                 startCaller();
  35         }
  36         return ptr;
  37 }
  38
  39
  40 void ForkedCallQueue::callNext()
  41 {
  42         if (callQueue_.empty())
  43                 return;
  44         Process pro = callQueue_.front();
  45         callQueue_.pop();
  46         // Bind our chain caller
  47         pro.second->connect(boost::bind(&ForkedCallQueue::callback,
  48                                          this, _1, _2));
  49         Forkedcall call;
  50         // If we fail to fork the process, then emit the signal
  51         // to tell the outside world that it failed.
  52         if (call.startscript(pro.first, pro.second) > 0) {
  53                 pro.second->operator()(0,1);
  54         }
  55 }
  56
  57
  58 void ForkedCallQueue::callback(pid_t, int)
  59 {
  60         if(callQueue_.empty()) {
  61                 stopCaller();
  62         } else {
  63                 callNext();
  64         }
  65 }
  66
  67 ForkedCallQueue::ForkedCallQueue() : running_(false)
  68 {}
  69
  70
  71 void ForkedCallQueue::startCaller()
  72 {
  73         lyxerr[Debug::GRAPHICS] << "ForkedCallQueue: waking up" << endl;
  74         running_ = true ;
  75         callNext();
  76 }
  77
  78
  79 void ForkedCallQueue::stopCaller()
  80 {
  81         running_ = false ;
  82         lyxerr[Debug::GRAPHICS] << "ForkedCallQueue: I'm going to sleep"
  83                                 << endl;
  84 }
  85
  86
  87 bool ForkedCallQueue::running() const
  88 {
  89         return running_ ;
  90 }