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