libs/ardour/worker.cc

   1 /*
   2   Copyright (C) 2012-2016 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, bool threaded)
  31         : _workee(workee)
  32         , _requests(threaded ? new RingBuffer<uint8_t>(ring_size) : NULL)
  33         , _responses(new RingBuffer<uint8_t>(ring_size))
  34         , _response((uint8_t*)malloc(ring_size))
  35         , _sem("worker_semaphore", 0)
  36         , _thread(NULL)
  37         , _exit(false)
  38         , _synchronous(!threaded)
  39 {
  40         if (threaded) {
  41                 _thread = Glib::Threads::Thread::create(
  42                         sigc::mem_fun(*this, &Worker::run));
  43         }
  44 }
  45
  46 Worker::~Worker()
  47 {
  48         _exit = true;
  49         _sem.signal();
  50         if (_thread) {
  51                 _thread->join();
  52         }
  53 }
  54
  55 bool
  56 Worker::schedule(uint32_t size, const void* data)
  57 {
  58         if (_synchronous || !_requests) {
  59                 _workee->work(*this, size, data);
  60                 return true;
  61         }
  62         if (_requests->write_space() < size + sizeof(size)) {
  63                 return false;
  64         }
  65         if (_requests->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  66                 return false;
  67         }
  68         if (_requests->write((const uint8_t*)data, size) != size) {
  69                 return false;
  70         }
  71         _sem.signal();
  72         return true;
  73 }
  74
  75 bool
  76 Worker::respond(uint32_t size, const void* data)
  77 {
  78         if (_responses->write_space() < size + sizeof(size)) {
  79                 return false;
  80         }
  81         if (_responses->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  82                 return false;
  83         }
  84         if (_responses->write((const uint8_t*)data, size) != size) {
  85                 return false;
  86         }
  87         return true;
  88 }
  89
  90 bool
  91 Worker::verify_message_completeness(RingBuffer<uint8_t>* rb)
  92 {
  93         uint32_t read_space = rb->read_space();
  94         uint32_t size;
  95         RingBuffer<uint8_t>::rw_vector vec;
  96         rb->get_read_vector (&vec);
  97         if (vec.len[0] + vec.len[1] < sizeof(size)) {
  98                 return false;
  99         }
 100         if (vec.len[0] >= sizeof(size)) {
 101                 memcpy (&size, vec.buf[0], sizeof (size));
 102         } else {
 103                 memcpy (&size, vec.buf[0], vec.len[0]);
 104                 memcpy (&size + vec.len[0], vec.buf[1], sizeof(size) - vec.len[0]);
 105         }
 106         if (read_space < size+sizeof(size)) {
 107                 /* message from writer is yet incomplete. respond next cycle */
 108                 return false;
 109         }
 110         return true;
 111 }
 112
 113 void
 114 Worker::emit_responses()
 115 {
 116         uint32_t read_space = _responses->read_space();
 117         uint32_t size       = 0;
 118         while (read_space >= sizeof(size)) {
 119                 if (!verify_message_completeness(_responses)) {
 120                         /* message from writer is yet incomplete. respond next cycle */
 121                         return;
 122                 }
 123                 /* read and send response */
 124                 _responses->read((uint8_t*)&size, sizeof(size));
 125                 _responses->read(_response, size);
 126                 _workee->work_response(size, _response);
 127                 read_space -= sizeof(size) + size;
 128         }
 129 }
 130
 131 void
 132 Worker::run()
 133 {
 134         void*  buf      = NULL;
 135         size_t buf_size = 0;
 136         while (true) {
 137                 _sem.wait();
 138                 if (_exit) {
 139                         free(buf);
 140                         return;
 141                 }
 142
 143                 uint32_t size = _requests->read_space();
 144                 if (size < sizeof(size)) {
 145                         PBD::error << "Worker: no work-data on ring buffer" << endmsg;
 146                         continue;
 147                 }
 148                 while (!verify_message_completeness(_requests)) {
 149                         Glib::usleep(2000);
 150                         if (_exit) {
 151                                 if (buf) free(buf);
 152                                 return;
 153                         }
 154                 }
 155                 if (_requests->read((uint8_t*)&size, sizeof(size)) < sizeof(size)) {
 156                         PBD::error << "Worker: Error reading size from request ring"
 157                                    << endmsg;
 158                         continue;
 159                 }
 160
 161                 if (size > buf_size) {
 162                         buf = realloc(buf, size);
 163                         if (buf) {
 164                                 buf_size = size;
 165                         } else {
 166                                 PBD::error << "Worker: Error allocating memory"
 167                                            << endmsg;
 168                                 buf_size = 0; // TODO: This is probably fatal
 169                         }
 170                 }
 171
 172                 if (_requests->read((uint8_t*)buf, size) < size) {
 173                         PBD::error << "Worker: Error reading body from request ring"
 174                                    << endmsg;
 175                         continue;  // TODO: This is probably fatal
 176                 }
 177
 178                 _workee->work(*this, size, buf);
 179         }
 180 }
 181
 182 } // namespace ARDOUR