libs/ardour/internal_return.cc

   1 /*
   2     Copyright (C) 2009 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 #include <glibmm/thread.h>
  20
  21 #include "pbd/failed_constructor.h"
  22
  23 #include "ardour/internal_return.h"
  24 #include "ardour/mute_master.h"
  25 #include "ardour/session.h"
  26
  27 using namespace std;
  28 using namespace ARDOUR;
  29
  30 PBD::Signal1<void,nframes_t> InternalReturn::CycleStart;
  31
  32 InternalReturn::InternalReturn (Session& s)
  33         : Return (s, true)
  34         , user_count (0)
  35 {
  36         CycleStart.connect_same_thread (*this, boost::bind (&InternalReturn::cycle_start, this, _1));
  37 }
  38
  39 void
  40 InternalReturn::run (BufferSet& bufs, sframes_t /*start_frame*/, sframes_t /*end_frame*/, nframes_t nframes, bool)
  41 {
  42         if (!_active && !_pending_active) {
  43                 return;
  44         }
  45
  46         /* no lock here, just atomic fetch */
  47
  48         if (g_atomic_int_get(&user_count) == 0) {
  49                 /* nothing to do - nobody is feeding us anything */
  50                 return;
  51         }
  52
  53         bufs.merge_from (buffers, nframes);
  54         _active = _pending_active;
  55 }
  56
  57 bool
  58 InternalReturn::configure_io (ChanCount in, ChanCount out)
  59 {
  60         IOProcessor::configure_io (in, out);
  61         allocate_buffers (_session.engine().frames_per_cycle());
  62         return true;
  63 }
  64
  65 void
  66 InternalReturn::set_block_size (nframes_t nframes)
  67 {
  68         allocate_buffers (nframes);
  69 }
  70
  71 void
  72 InternalReturn::allocate_buffers (nframes_t nframes)
  73 {
  74         buffers.ensure_buffers (_configured_input, nframes);
  75         buffers.set_count (_configured_input);
  76 }
  77
  78 BufferSet*
  79 InternalReturn::get_buffers ()
  80 {
  81         Glib::Mutex::Lock lm (_session.engine().process_lock());
  82         /* use of g_atomic here is just for code consistency - its protected by the lock
  83            for writing.
  84         */
  85         g_atomic_int_inc (&user_count);
  86         return &buffers;
  87 }
  88
  89 void
  90 InternalReturn::release_buffers ()
  91 {
  92         Glib::Mutex::Lock lm (_session.engine().process_lock());
  93         if (user_count) {
  94                 /* use of g_atomic here is just for code consistency - its protected by the lock
  95                    for writing.
  96                 */
  97                 (void) g_atomic_int_dec_and_test (&user_count);
  98         }
  99 }
 100
 101 void
 102 InternalReturn::cycle_start (nframes_t nframes)
 103 {
 104         /* called from process cycle - no lock necessary */
 105         if (user_count) {
 106                 /* don't bother with this if nobody is going to feed us anything */
 107                 buffers.silence (nframes, 0);
 108         }
 109 }
 110
 111 XMLNode&
 112 InternalReturn::state (bool full)
 113 {
 114         XMLNode& node (Return::state (full));
 115         /* override type */
 116         node.add_property("type", "intreturn");
 117         return node;
 118 }
 119
 120 XMLNode&
 121 InternalReturn::get_state()
 122 {
 123         return state (true);
 124 }
 125
 126 int
 127 InternalReturn::set_state (const XMLNode& node, int version)
 128 {
 129         return Return::set_state (node, version);
 130 }
 131
 132 bool
 133 InternalReturn::can_support_io_configuration (const ChanCount& in, ChanCount& out) const
 134 {
 135         out = in;
 136         return true;
 137 }
 138
 139 bool
 140 InternalReturn::visible () const
 141 {
 142         return false;
 143 }