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         delete _responses;
  54         delete _requests;
  55         free (_response);
  56 }
  57
  58 bool
  59 Worker::schedule(uint32_t size, const void* data)
  60 {
  61         if (_synchronous || !_requests) {
  62                 _workee->work(*this, size, data);
  63                 return true;
  64         }
  65         if (_requests->write_space() < size + sizeof(size)) {
  66                 return false;
  67         }
  68         if (_requests->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  69                 return false;
  70         }
  71         if (_requests->write((const uint8_t*)data, size) != size) {
  72                 return false;
  73         }
  74         _sem.signal();
  75         return true;
  76 }
  77
  78 bool
  79 Worker::respond(uint32_t size, const void* data)
  80 {
  81         if (_responses->write_space() < size + sizeof(size)) {
  82                 return false;
  83         }
  84         if (_responses->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  85                 return false;
  86         }
  87         if (_responses->write((const uint8_t*)data, size) != size) {
  88                 return false;
  89         }
  90         return true;
  91 }
  92
  93 bool
  94 Worker::verify_message_completeness(RingBuffer<uint8_t>* rb)
  95 {
  96         uint32_t read_space = rb->read_space();
  97         uint32_t size;
  98         RingBuffer<uint8_t>::rw_vector vec;
  99         rb->get_read_vector (&vec);
 100         if (vec.len[0] + vec.len[1] < sizeof(size)) {
 101                 return false;
 102         }
 103         if (vec.len[0] >= sizeof(size)) {
 104                 memcpy (&size, vec.buf[0], sizeof (size));
 105         } else {
 106                 memcpy (&size, vec.buf[0], vec.len[0]);
 107                 memcpy (&size + vec.len[0], vec.buf[1], sizeof(size) - vec.len[0]);
 108         }
 109         if (read_space < size+sizeof(size)) {
 110                 /* message from writer is yet incomplete. respond next cycle */
 111                 return false;
 112         }
 113         return true;
 114 }
 115
 116 void
 117 Worker::emit_responses()
 118 {
 119         uint32_t read_space = _responses->read_space();
 120         uint32_t size       = 0;
 121         while (read_space >= sizeof(size)) {
 122                 if (!verify_message_completeness(_responses)) {
 123                         /* message from writer is yet incomplete. respond next cycle */
 124                         return;
 125                 }
 126                 /* read and send response */
 127                 _responses->read((uint8_t*)&size, sizeof(size));
 128                 _responses->read(_response, size);
 129                 _workee->work_response(size, _response);
 130                 read_space -= sizeof(size) + size;
 131         }
 132 }
 133
 134 void
 135 Worker::run()
 136 {
 137         void*  buf      = NULL;
 138         size_t buf_size = 0;
 139         while (true) {
 140                 _sem.wait();
 141                 if (_exit) {
 142                         free(buf);
 143                         return;
 144                 }
 145
 146                 uint32_t size = _requests->read_space();
 147                 if (size < sizeof(size)) {
 148                         PBD::error << "Worker: no work-data on ring buffer" << endmsg;
 149                         continue;
 150                 }
 151                 while (!verify_message_completeness(_requests)) {
 152                         Glib::usleep(2000);
 153                         if (_exit) {
 154                                 if (buf) free(buf);
 155                                 return;
 156                         }
 157                 }
 158                 if (_requests->read((uint8_t*)&size, sizeof(size)) < sizeof(size)) {
 159                         PBD::error << "Worker: Error reading size from request ring"
 160                                    << endmsg;
 161                         continue;
 162                 }
 163
 164                 if (size > buf_size) {
 165                         buf = realloc(buf, size);
 166                         if (buf) {
 167                                 buf_size = size;
 168                         } else {
 169                                 PBD::error << "Worker: Error allocating memory"
 170                                            << endmsg;
 171                                 buf_size = 0; // TODO: This is probably fatal
 172                         }
 173                 }
 174
 175                 if (_requests->read((uint8_t*)buf, size) < size) {
 176                         PBD::error << "Worker: Error reading body from request ring"
 177                                    << endmsg;
 178                         continue;  // TODO: This is probably fatal
 179                 }
 180
 181                 _workee->work(*this, size, buf);
 182         }
 183 }
 184
 185 } // namespace ARDOUR