diff options
Diffstat (limited to 'libs/ardour/audioengine.cc')
| -rw-r--r-- | libs/ardour/audioengine.cc | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc index 3b85ea2147..cbdd1fda1c 100644 --- a/libs/ardour/audioengine.cc +++ b/libs/ardour/audioengine.cc @@ -255,6 +255,11 @@ AudioEngine::_graph_order_callback (void *arg) return 0; } +/** Wrapped which is called by JACK as its process callback. It is just + * here to get us back into C++ land by calling AudioEngine::process_callback() + * @param nframes Number of frames passed by JACK. + * @param arg User argument passed by JACK, which will be the AudioEngine*. + */ int AudioEngine::_process_callback (nframes_t nframes, void *arg) { @@ -267,11 +272,17 @@ AudioEngine::_freewheel_callback (int onoff, void *arg) static_cast<AudioEngine*>(arg)->_freewheeling = onoff; } +/** Method called by JACK (via _process_callback) which says that there + * is work to be done. + * @param nframes Number of frames to process. + */ int AudioEngine::process_callback (nframes_t nframes) { // CycleTimer ct ("AudioEngine::process"); Glib::Mutex::Lock tm (_process_lock, Glib::TRY_LOCK); + + /// The number of frames that will have been processed when we've finished nframes_t next_processed_frames; /* handle wrap around of total frames counter */ @@ -281,13 +292,15 @@ AudioEngine::process_callback (nframes_t nframes) } else { next_processed_frames = _processed_frames + nframes; } - + if (!tm.locked() || session == 0) { + /* return having done nothing */ _processed_frames = next_processed_frames; return 0; } if (session_remove_pending) { + /* perform the actual session removal */ session = 0; session_remove_pending = false; session_removed.signal(); @@ -296,6 +309,7 @@ AudioEngine::process_callback (nframes_t nframes) } if (_freewheeling) { + /* emit the Freewheel signal and stop freewheeling in the event of trouble */ if (Freewheel (nframes)) { cerr << "Freewheeling returned non-zero!\n"; _freewheeling = false; |