src/support/ForkedCallQueue.cpp

   1 /**
   2  * \file ForkedCallQueue.cpp
   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 "support/ForkedCallQueue.h"
  14
  15 #include "debug.h"
  16
  17 #include <boost/bind.hpp>
  18
  19
  20 using std::string;
  21 using std::endl;
  22
  23
  24 namespace lyx {
  25 namespace support {
  26
  27 ForkedCallQueue & ForkedCallQueue::get()
  28 {
  29         static ForkedCallQueue singleton;
  30         return singleton;
  31 }
  32
  33
  34 Forkedcall::SignalTypePtr ForkedCallQueue::add(string const & process)
  35 {
  36         Forkedcall::SignalTypePtr ptr;
  37         ptr.reset(new Forkedcall::SignalType);
  38         callQueue_.push(Process(process, ptr));
  39         if (!running_) {
  40                 startCaller();
  41         }
  42         return ptr;
  43 }
  44
  45
  46 void ForkedCallQueue::callNext()
  47 {
  48         if (callQueue_.empty())
  49                 return;
  50         Process pro = callQueue_.front();
  51         callQueue_.pop();
  52         // Bind our chain caller
  53         pro.second->connect(boost::bind(&ForkedCallQueue::callback,
  54                                          this, _1, _2));
  55         Forkedcall call;
  56         // If we fail to fork the process, then emit the signal
  57         // to tell the outside world that it failed.
  58         if (call.startscript(pro.first, pro.second) > 0) {
  59                 pro.second->operator()(0,1);
  60         }
  61 }
  62
  63
  64 void ForkedCallQueue::callback(pid_t, int)
  65 {
  66         if (callQueue_.empty()) {
  67                 stopCaller();
  68         } else {
  69                 callNext();
  70         }
  71 }
  72
  73 ForkedCallQueue::ForkedCallQueue() : running_(false)
  74 {}
  75
  76
  77 void ForkedCallQueue::startCaller()
  78 {
  79         LYXERR(Debug::GRAPHICS) << "ForkedCallQueue: waking up" << endl;
  80         running_ = true ;
  81         callNext();
  82 }
  83
  84
  85 void ForkedCallQueue::stopCaller()
  86 {
  87         running_ = false ;
  88         LYXERR(Debug::GRAPHICS) << "ForkedCallQueue: I'm going to sleep"
  89                                 << endl;
  90 }
  91
  92
  93 bool ForkedCallQueue::running() const
  94 {
  95         return running_ ;
  96 }
  97
  98 } // namespace support
  99 } // namespace lyx