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 <config.h>
  12
  13 #include "forkedcallqueue.h"
  14
  15 #include "debug.h"
  16
  17 #include <boost/bind.hpp>
  18 #include <boost/signals/signal2.hpp>
  19
  20 using std::endl;
  21 using std::queue;
  22
  23 ForkedCallQueue & ForkedCallQueue::get()
  24 {
  25         static ForkedCallQueue singleton;
  26         return singleton;
  27 }
  28
  29
  30 Forkedcall::SignalTypePtr ForkedCallQueue::add(string const & process)
  31 {
  32         Forkedcall::SignalTypePtr ptr;
  33         ptr.reset(new Forkedcall::SignalType);
  34         callQueue_.push(Process(process, ptr));
  35         if (!running_) {
  36                 startCaller();
  37         }
  38         return ptr;
  39 }
  40
  41
  42 void ForkedCallQueue::callNext()
  43 {
  44         if (callQueue_.empty())
  45                 return;
  46         Process pro = callQueue_.front();
  47         callQueue_.pop();
  48         // Bind our chain caller
  49         pro.second->connect(boost::bind(&ForkedCallQueue::callback,
  50                                          this, _1, _2));
  51         Forkedcall call;
  52         // If we fail to fork the process, then emit the signal
  53         // to tell the outside world that it failed.
  54         if (call.startscript(pro.first, pro.second) > 0) {
  55                 pro.second->operator()(0,1);
  56         }
  57 }
  58
  59
  60 void ForkedCallQueue::callback(pid_t, int)
  61 {
  62         if(callQueue_.empty()) {
  63                 stopCaller();
  64         } else {
  65                 callNext();
  66         }
  67 }
  68
  69 ForkedCallQueue::ForkedCallQueue() : running_(false)
  70 {}
  71
  72
  73 void ForkedCallQueue::startCaller()
  74 {
  75         lyxerr[Debug::GRAPHICS] << "ForkedCallQueue: waking up" << endl;
  76         running_ = true ;
  77         callNext();
  78 }
  79
  80
  81 void ForkedCallQueue::stopCaller()
  82 {
  83         running_ = false ;
  84         lyxerr[Debug::GRAPHICS] << "ForkedCallQueue: I'm going to sleep"
  85                                 << endl;
  86 }
  87
  88
  89 bool ForkedCallQueue::running() const
  90 {
  91         return running_ ;
  92 }