Allow AudioDiskstream to have 0 channels without crashing. Fixes crash on record...

git-svn-id: svn://localhost/ardour2/branches/3.0@8408 d708f5d6-7413-0410-9779-e7cbd77b26cf

diff --git a/libs/ardour/audio_diskstream.cc b/libs/ardour/audio_diskstream.cc
index 5abdb97b3389155e7b0757e4d4d409d196bf9ae5..8428e05b39151fa6fd35d2f6c2890d29e02e239c 100644 (file)
--- a/libs/ardour/audio_diskstream.cc
+++ b/libs/ardour/audio_diskstream.cc
@@ -114,9 +114,6 @@ AudioDiskstream::init ()
 
        set_block_size (_session.get_block_size());
        allocate_temporary_buffers ();
-
-       add_channel (1);
-       assert(_n_channels == ChanCount(DataType::AUDIO, 1));
 }
 
 AudioDiskstream::~AudioDiskstream ()
@@ -410,8 +407,7 @@ AudioDiskstream::prepare_record_status(framepos_t capture_start_frame)
                                transvec.buf[0]->type = CaptureStart;
                                transvec.buf[0]->capture_val = capture_start_frame;
                                (*chan)->capture_transition_buf->increment_write_ptr(1);
-                       }
-                       else {
+                       } else {
                                // bad!
                                fatal << X_("programming error: capture_transition_buf is full on rec start!  inconceivable!")
                                        << endmsg;
@@ -708,7 +704,11 @@ AudioDiskstream::commit (framecnt_t /* nframes */)
                capture_captured += adjust_capture_position;
                adjust_capture_position = 0;
        }
-
+       
+       if (c->empty()) {
+               return false;
+       }
+       
        if (_slaved) {
                if (_io && _io->active()) {
                        need_butler = c->front()->playback_buf->write_space() >= c->front()->playback_buf->bufsize() / 2;
@@ -735,13 +735,22 @@ AudioDiskstream::set_pending_overwrite (bool yn)
        _pending_overwrite = yn;
 
        overwrite_frame = playback_sample;
-       overwrite_offset = channels.reader()->front()->playback_buf->get_read_ptr();
+
+       boost::shared_ptr<ChannelList> c = channels.reader ();
+       if (!c->empty ()) {
+               overwrite_offset = c->front()->playback_buf->get_read_ptr();
+       }
 }
 
 int
 AudioDiskstream::overwrite_existing_buffers ()
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
+       if (c->empty ()) {
+               _pending_overwrite = false;
+               return 0;
+       }
+       
        Sample* mixdown_buffer;
        float* gain_buffer;
        int ret = -1;
@@ -2137,6 +2146,10 @@ AudioDiskstream::playback_buffer_load () const
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
 
+       if (c->empty ()) {
+               return 0;
+       }
+
        return (float) ((double) c->front()->playback_buf->read_space()/
                        (double) c->front()->playback_buf->bufsize());
 }
@@ -2146,6 +2159,10 @@ AudioDiskstream::capture_buffer_load () const
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
 
+       if (c->empty ()) {
+               return 0;
+       }
+       
        return (float) ((double) c->front()->capture_buf->write_space()/
                        (double) c->front()->capture_buf->bufsize());
 }