libs/ardour/worker.cc

   1 /*
   2   Copyright (C) 2012 Paul Davis
   3   Author: David Robillard
   4
   5   This program is free software; you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation; either version 2 of the License, or
   8   (at your option) any later version.
   9
  10   This program is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program; if not, write to the Free Software
  17   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22
  23 #include "ardour/worker.h"
  24 #include "pbd/error.h"
  25
  26 #include <glibmm/timer.h>
  27
  28 namespace ARDOUR {
  29
  30 Worker::Worker(Workee* workee, uint32_t ring_size)
  31         : _workee(workee)
  32         , _requests(new RingBuffer<uint8_t>(ring_size))
  33         , _responses(new RingBuffer<uint8_t>(ring_size))
  34         , _response((uint8_t*)malloc(ring_size))
  35         , _sem(0)
  36         , _exit(false)
  37         , _thread (Glib::Threads::Thread::create(sigc::mem_fun(*this, &Worker::run)))
  38 {}
  39
  40 Worker::~Worker()
  41 {
  42         _exit = true;
  43         _sem.post();
  44         _thread->join();
  45 }
  46
  47 bool
  48 Worker::schedule(uint32_t size, const void* data)
  49 {
  50         if (_requests->write_space() < size + sizeof(size)) {
  51                 return false;
  52         }
  53         if (_requests->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  54                 return false;
  55         }
  56         if (_requests->write((const uint8_t*)data, size) != size) {
  57                 return false;
  58         }
  59         _sem.post();
  60         return true;
  61 }
  62
  63 bool
  64 Worker::respond(uint32_t size, const void* data)
  65 {
  66         if (_requests->write_space() < size + sizeof(size)) {
  67                 return false;
  68         }
  69         if (_responses->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  70                 return false;
  71         }
  72         if (_responses->write((const uint8_t*)data, size) != size) {
  73                 return false;
  74         }
  75         return true;
  76 }
  77
  78 bool
  79 Worker::verify_message_completeness(RingBuffer<uint8_t>* rb)
  80 {
  81         uint32_t read_space = rb->read_space();
  82         uint32_t size;
  83         RingBuffer<uint8_t>::rw_vector vec;
  84         rb->get_read_vector (&vec);
  85         if (vec.len[0] >= sizeof(size)) {
  86                 memcpy (&size, vec.buf[0], sizeof (size));
  87         } else {
  88                 memcpy (&size, vec.buf[0], vec.len[0]);
  89                 memcpy (&size + vec.len[0], vec.buf[1], sizeof(size) - vec.len[0]);
  90         }
  91         if (read_space < size+sizeof(size)) {
  92                 /* message from writer is yet incomplete. respond next cycle */
  93                 return false;
  94         }
  95         return true;
  96 }
  97
  98 void
  99 Worker::emit_responses()
 100 {
 101         uint32_t read_space = _responses->read_space();
 102         uint32_t size       = 0;
 103         while (read_space >= sizeof(size)) {
 104                 if (!verify_message_completeness(_responses)) {
 105                         /* message from writer is yet incomplete. respond next cycle */
 106                         return;
 107                 }
 108                 /* read and send response */
 109                 _responses->read((uint8_t*)&size, sizeof(size));
 110                 _responses->read(_response, size);
 111                 _workee->work_response(size, _response);
 112                 read_space -= sizeof(size) + size;
 113         }
 114 }
 115
 116 void
 117 Worker::run()
 118 {
 119         void*  buf      = NULL;
 120         size_t buf_size = 0;
 121         while (true) {
 122                 _sem.wait();
 123                 if (_exit) {
 124                         return;
 125                 }
 126
 127                 uint32_t size = _requests->read_space();
 128                 if (size < sizeof(size)) {
 129                         PBD::error << "Worker: no work-data on ring buffer" << endmsg;
 130                         continue;
 131                 }
 132                 while (!verify_message_completeness(_requests)) {
 133                         Glib::usleep(2000);
 134                         if (_exit) {
 135                                 return;
 136                         }
 137                 }
 138                 if (_requests->read((uint8_t*)&size, sizeof(size)) < sizeof(size)) {
 139                         PBD::error << "Worker: Error reading size from request ring"
 140                                    << endmsg;
 141                         continue;
 142                 }
 143
 144                 if (size > buf_size) {
 145                         buf = realloc(buf, size);
 146                         buf_size = size;
 147                 }
 148
 149                 if (_requests->read((uint8_t*)buf, size) < size) {
 150                         PBD::error << "Worker: Error reading body from request ring"
 151                                    << endmsg;
 152                         continue;  // TODO: This is probably fatal
 153                 }
 154
 155                 _workee->work(size, buf);
 156         }
 157 }
 158
 159 } // namespace ARDOUR