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 #include "pbd/compose.h"
  26
  27 #include <glibmm/timer.h>
  28
  29 namespace ARDOUR {
  30
  31 Worker::Worker(Workee* workee, uint32_t ring_size, bool threaded)
  32         : _workee(workee)
  33         , _requests(threaded ? new PBD::RingBuffer<uint8_t>(ring_size) : NULL)
  34         , _responses(new PBD::RingBuffer<uint8_t>(ring_size))
  35         , _response((uint8_t*)malloc(ring_size))
  36         , _sem(string_compose ("worker_semaphore%1", this).c_str(), 0)
  37         , _thread(NULL)
  38         , _exit(false)
  39         , _synchronous(!threaded)
  40 {
  41         if (threaded) {
  42                 _thread = Glib::Threads::Thread::create(
  43                         sigc::mem_fun(*this, &Worker::run));
  44         }
  45 }
  46
  47 Worker::~Worker()
  48 {
  49         _exit = true;
  50         _sem.signal();
  51         if (_thread) {
  52                 _thread->join();
  53         }
  54         delete _responses;
  55         delete _requests;
  56         free (_response);
  57 }
  58
  59 bool
  60 Worker::schedule(uint32_t size, const void* data)
  61 {
  62         if (_synchronous || !_requests) {
  63                 _workee->work(*this, size, data);
  64                 emit_responses ();
  65                 return true;
  66         }
  67         if (_requests->write_space() < size + sizeof(size)) {
  68                 return false;
  69         }
  70         if (_requests->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  71                 return false;
  72         }
  73         if (_requests->write((const uint8_t*)data, size) != size) {
  74                 return false;
  75         }
  76         _sem.signal();
  77         return true;
  78 }
  79
  80 bool
  81 Worker::respond(uint32_t size, const void* data)
  82 {
  83         if (_responses->write_space() < size + sizeof(size)) {
  84                 return false;
  85         }
  86         if (_responses->write((const uint8_t*)&size, sizeof(size)) != sizeof(size)) {
  87                 return false;
  88         }
  89         if (_responses->write((const uint8_t*)data, size) != size) {
  90                 return false;
  91         }
  92         return true;
  93 }
  94
  95 bool
  96 Worker::verify_message_completeness(PBD::RingBuffer<uint8_t>* rb)
  97 {
  98         uint32_t read_space = rb->read_space();
  99         uint32_t size;
 100         PBD::RingBuffer<uint8_t>::rw_vector vec;
 101         rb->get_read_vector (&vec);
 102         if (vec.len[0] + vec.len[1] < sizeof(size)) {
 103                 return false;
 104         }
 105         if (vec.len[0] >= sizeof(size)) {
 106                 memcpy (&size, vec.buf[0], sizeof (size));
 107         } else {
 108                 memcpy (&size, vec.buf[0], vec.len[0]);
 109                 memcpy (&size + vec.len[0], vec.buf[1], sizeof(size) - vec.len[0]);
 110         }
 111         if (read_space < size+sizeof(size)) {
 112                 /* message from writer is yet incomplete. respond next cycle */
 113                 return false;
 114         }
 115         return true;
 116 }
 117
 118 void
 119 Worker::emit_responses()
 120 {
 121         uint32_t read_space = _responses->read_space();
 122         uint32_t size       = 0;
 123         while (read_space >= sizeof(size)) {
 124                 if (!verify_message_completeness(_responses)) {
 125                         /* message from writer is yet incomplete. respond next cycle */
 126                         return;
 127                 }
 128                 /* read and send response */
 129                 _responses->read((uint8_t*)&size, sizeof(size));
 130                 _responses->read(_response, size);
 131                 _workee->work_response(size, _response);
 132                 read_space -= sizeof(size) + size;
 133         }
 134 }
 135
 136 void
 137 Worker::run()
 138 {
 139         void*  buf      = NULL;
 140         size_t buf_size = 0;
 141         while (true) {
 142                 _sem.wait();
 143                 if (_exit) {
 144                         free(buf);
 145                         return;
 146                 }
 147
 148                 uint32_t size = _requests->read_space();
 149                 if (size < sizeof(size)) {
 150                         PBD::error << "Worker: no work-data on ring buffer" << endmsg;
 151                         continue;
 152                 }
 153                 while (!verify_message_completeness(_requests)) {
 154                         Glib::usleep(2000);
 155                         if (_exit) {
 156                                 if (buf) free(buf);
 157                                 return;
 158                         }
 159                 }
 160                 if (_requests->read((uint8_t*)&size, sizeof(size)) < sizeof(size)) {
 161                         PBD::error << "Worker: Error reading size from request ring"
 162                                    << endmsg;
 163                         continue;
 164                 }
 165
 166                 if (size > buf_size) {
 167                         buf = realloc(buf, size);
 168                         if (buf) {
 169                                 buf_size = size;
 170                         } else {
 171                                 PBD::error << "Worker: Error allocating memory"
 172                                            << endmsg;
 173                                 buf_size = 0; // TODO: This is probably fatal
 174                         }
 175                 }
 176
 177                 if (_requests->read((uint8_t*)buf, size) < size) {
 178                         PBD::error << "Worker: Error reading body from request ring"
 179                                    << endmsg;
 180                         continue;  // TODO: This is probably fatal
 181                 }
 182
 183                 _workee->work(*this, size, buf);
 184         }
 185 }
 186
 187 } // namespace ARDOUR