src/lib/butler.cc

   1 /*
   2     Copyright (C) 2016-2017 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 #include "butler.h"
  22 #include "player.h"
  23 #include <boost/weak_ptr.hpp>
  24 #include <boost/shared_ptr.hpp>
  25
  26 using std::cout;
  27 using std::pair;
  28 using std::make_pair;
  29 using boost::weak_ptr;
  30 using boost::shared_ptr;
  31 using boost::bind;
  32 using boost::optional;
  33
  34 /** Video readahead in frames */
  35 #define VIDEO_READAHEAD 10
  36
  37 Butler::Butler (weak_ptr<const Film> film, shared_ptr<Player> player)
  38         : _film (film)
  39         , _player (player)
  40         , _pending_seek_accurate (false)
  41         , _finished (false)
  42 {
  43         _player->Video.connect (bind (&VideoRingBuffers::put, &_video, _1, _2));
  44         _thread = new boost::thread (bind (&Butler::thread, this));
  45 }
  46
  47 Butler::~Butler ()
  48 {
  49         _thread->interrupt ();
  50         try {
  51                 _thread->join ();
  52         } catch (boost::thread_interrupted& e) {
  53                 /* No problem */
  54         }
  55         delete _thread;
  56 }
  57
  58 void
  59 Butler::thread ()
  60 {
  61         while (true) {
  62                 boost::mutex::scoped_lock lm (_mutex);
  63
  64                 while (_video.size() > VIDEO_READAHEAD && !_pending_seek_position) {
  65                         _summon.wait (lm);
  66                 }
  67
  68                 if (_pending_seek_position) {
  69                         _player->seek (*_pending_seek_position, _pending_seek_accurate);
  70                         _pending_seek_position = optional<DCPTime> ();
  71                 }
  72
  73                 while (_video.size() < VIDEO_READAHEAD) {
  74                         _arrived.notify_all ();
  75                         if (_player->pass ()) {
  76                                 _finished = true;
  77                                 break;
  78                         }
  79                 }
  80         }
  81 }
  82
  83 pair<shared_ptr<PlayerVideo>, DCPTime>
  84 Butler::get_video ()
  85 {
  86         boost::mutex::scoped_lock lm (_mutex);
  87         while (_video.size() == 0 && !_finished) {
  88                 _arrived.wait (lm);
  89         }
  90
  91         if (_finished) {
  92                 return make_pair (shared_ptr<PlayerVideo>(), DCPTime());
  93         }
  94
  95         return _video.get ();
  96 }
  97
  98 void
  99 Butler::seek (DCPTime position, bool accurate)
 100 {
 101         _video.clear ();
 102
 103         {
 104                 boost::mutex::scoped_lock lm (_mutex);
 105                 _finished = false;
 106                 _pending_seek_position = position;
 107                 _pending_seek_accurate = accurate;
 108         }
 109
 110         _summon.notify_all ();
 111 }