commits 6001-6525 inclusive from 2.X applied to 3.0

[ardour2.git] / libs / ardour / session_transport.cc

/*
    Copyright (C) 1999-2003 Paul Davis

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <cmath>
#include <cerrno>
#include <unistd.h>


#include "pbd/undo.h"
#include "pbd/error.h"
#include "pbd/enumwriter.h"
#include "pbd/pthread_utils.h"
#include "pbd/memento_command.h"

#include "midi++/mmc.h"
#include "midi++/port.h"

#include "ardour/ardour.h"
#include "ardour/audio_diskstream.h"
#include "ardour/audioengine.h"
#include "ardour/auditioner.h"
#include "ardour/butler.h"
#include "ardour/debug.h"
#include "ardour/location.h"
#include "ardour/session.h"
#include "ardour/slave.h"

#include "i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace PBD;

void
Session::add_post_transport_work (PostTransportWork ptw)
{
        PostTransportWork oldval;
        PostTransportWork newval;
        int tries = 0;

        while (tries < 8) {
                oldval = (PostTransportWork) g_atomic_int_get (&_post_transport_work);
                newval = PostTransportWork (oldval | ptw);
                if (g_atomic_int_compare_and_exchange (&_post_transport_work, oldval, newval)) {
                        /* success */
                        return;
                }
        }

        error << "Could not set post transport work! Crazy thread madness, call the programmers" << endmsg;
}

void
Session::request_input_change_handling ()
{
        if (!(_state_of_the_state & (InitialConnecting|Deletion))) {
                SessionEvent* ev = new SessionEvent (SessionEvent::InputConfigurationChange, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
                queue_event (ev);
        }
}

void
Session::request_sync_source (Slave* new_slave)
{
        SessionEvent* ev = new SessionEvent (SessionEvent::SetSyncSource, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
        bool seamless;

        seamless = Config->get_seamless_loop ();

        if (dynamic_cast<JACK_Slave*>(new_slave)) {
                /* JACK cannot support seamless looping at present */
                Config->set_seamless_loop (false);
        } else {
                /* reset to whatever the value was before we last switched slaves */
                Config->set_seamless_loop (_was_seamless);
        }

        /* save value of seamless from before the switch */
        _was_seamless = seamless;

        ev->slave = new_slave;
        queue_event (ev);
}

void
Session::request_transport_speed (double speed)
{
        SessionEvent* ev = new SessionEvent (SessionEvent::SetTransportSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, speed);
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Request transport speed = %1\n", speed));
        queue_event (ev);
}

void
Session::request_diskstream_speed (Diskstream& ds, double speed)
{
        SessionEvent* ev = new SessionEvent (SessionEvent::SetDiskstreamSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, speed);
        ev->set_ptr (&ds);
        queue_event (ev);
}

void
Session::request_stop (bool abort, bool clear_state)
{
        SessionEvent* ev = new SessionEvent (SessionEvent::SetTransportSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0, abort, clear_state);
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Request transport stop, abort = %1, clear state = %2\n", abort, clear_state));
        queue_event (ev);
}

void
Session::request_locate (nframes_t target_frame, bool with_roll)
{
        SessionEvent *ev = new SessionEvent (with_roll ? SessionEvent::LocateRoll : SessionEvent::Locate, SessionEvent::Add, SessionEvent::Immediate, target_frame, 0, false);
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Request locate to %1\n", target_frame));
        queue_event (ev);
}

void
Session::force_locate (nframes64_t target_frame, bool with_roll)
{
        SessionEvent *ev = new SessionEvent (with_roll ? SessionEvent::LocateRoll : SessionEvent::Locate, SessionEvent::Add, SessionEvent::Immediate, target_frame, 0, true);
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Request forced locate to %1\n", target_frame));
        queue_event (ev);
}

void
Session::request_play_loop (bool yn, bool leave_rolling)
{
        SessionEvent* ev;
        Location *location = _locations.auto_loop_location();

        if (location == 0 && yn) {
                error << _("Cannot loop - no loop range defined")
                      << endmsg;
                return;
        }

        ev = new SessionEvent (SessionEvent::SetLoop, SessionEvent::Add, SessionEvent::Immediate, 0, (leave_rolling ? 1.0 : 0.0), yn);
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Request set loop = %1, leave rolling ? %2\n", yn, leave_rolling));
        queue_event (ev);

        if (!leave_rolling && !yn && Config->get_seamless_loop() && transport_rolling()) {
                // request an immediate locate to refresh the diskstreams
                // after disabling looping
                request_locate (_transport_frame-1, false);
        }
}

void
Session::request_play_range (list<AudioRange>* range, bool leave_rolling)
{
        SessionEvent* ev = new SessionEvent (SessionEvent::SetPlayAudioRange, SessionEvent::Add, SessionEvent::Immediate, 0, (leave_rolling ? 1.0 : 0.0));
        if (range) {
                ev->audio_range = *range;
        } else {
                ev->audio_range.clear ();
        }
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Request play range, leave rolling ? %1\n", leave_rolling));
        queue_event (ev);
}

void
Session::realtime_stop (bool abort, bool clear_state)
{
        DEBUG_TRACE (DEBUG::Transport, "realtime stop\n");
        PostTransportWork todo = PostTransportWork (0);

        /* assume that when we start, we'll be moving forwards */

        // FIXME: where should this really be? [DR]
        //send_full_time_code();
        deliver_mmc (MIDI::MachineControl::cmdStop, 0);
        deliver_mmc (MIDI::MachineControl::cmdLocate, _transport_frame);

        if (_transport_speed < 0.0f) {
                todo = (PostTransportWork (todo | PostTransportStop | PostTransportReverse));
        } else {
                todo = PostTransportWork (todo | PostTransportStop);
        }

        if (actively_recording()) {

                /* move the transport position back to where the
                   request for a stop was noticed. we rolled
                   past that point to pick up delayed input (and/or to delick)
                */

                if (_worst_output_latency > current_block_size) {
                        /* we rolled past the stop point to pick up data that had
                           not yet arrived. move back to where the stop occured.
                        */
                        decrement_transport_position (current_block_size + (_worst_output_latency - current_block_size));
                } else {
                        decrement_transport_position (current_block_size);
                }

                /* the duration change is not guaranteed to have happened, but is likely */

                todo = PostTransportWork (todo | PostTransportDuration);
        }

        if (abort) {
                todo = PostTransportWork (todo | PostTransportAbort);
        }

        if (clear_state) {
                todo = PostTransportWork (todo | PostTransportClearSubstate);
        }

        if (todo) {
                add_post_transport_work (todo);
        }

        _clear_event_type (SessionEvent::StopOnce);
        _clear_event_type (SessionEvent::RangeStop);
        _clear_event_type (SessionEvent::RangeLocate);

        /* if we're going to clear loop state, then force disabling record BUT only if we're not doing latched rec-enable */
        disable_record (true, (!Config->get_latched_record_enable() && clear_state));
        
        reset_slave_state ();

        _transport_speed = 0;
        _target_transport_speed = 0;

        if (config.get_use_video_sync()) {
                waiting_for_sync_offset = true;
        }

        transport_sub_state = ((!config.get_external_sync()&& config.get_auto_return()) ? AutoReturning : 0);
}

void
Session::butler_transport_work ()
{
  restart:
        bool finished;
        PostTransportWork ptw;
        boost::shared_ptr<RouteList> r = routes.reader ();
        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        int on_entry = g_atomic_int_get (&_butler->should_do_transport_work);
        finished = true;
        ptw = post_transport_work();

        DEBUG_TRACE (DEBUG::Transport, string_compose ("Butler transport work, todo = %1\n", enum_2_string (ptw)));
                     
        if (ptw & PostTransportCurveRealloc) {
                for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
                        (*i)->curve_reallocate();
                }
        }

        if (ptw & PostTransportInputChange) {
                for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                        (*i)->non_realtime_input_change ();
                }
        }

        if (ptw & PostTransportSpeed) {
                non_realtime_set_speed ();
        }

        if (ptw & PostTransportReverse) {

                clear_clicks();
                cumulative_rf_motion = 0;
                reset_rf_scale (0);

                /* don't seek if locate will take care of that in non_realtime_stop() */

                if (!(ptw & PostTransportLocate)) {

                        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                if (!(*i)->hidden()) {
                                        (*i)->non_realtime_locate (_transport_frame);
                                }
                                if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
                                        /* new request, stop seeking, and start again */
                                        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
                                        goto restart;
                                }
                        }
                }
        }

        if (ptw & PostTransportLocate) {
                non_realtime_locate ();
        }

        if (ptw & PostTransportStop) {
                non_realtime_stop (ptw & PostTransportAbort, on_entry, finished);
                if (!finished) {
                        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
                        goto restart;
                }
        }

        if (ptw & PostTransportOverWrite) {
                non_realtime_overwrite (on_entry, finished);
                if (!finished) {
                        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
                        goto restart;
                }
        }

        if (ptw & PostTransportAudition) {
                non_realtime_set_audition ();
        }

        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);

        DEBUG_TRACE (DEBUG::Transport, X_("Butler transport work all done\n"));
}

void
Session::non_realtime_set_speed ()
{
        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                (*i)->non_realtime_set_speed ();
        }
}

void
Session::non_realtime_overwrite (int on_entry, bool& finished)
{
        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                if ((*i)->pending_overwrite) {
                        (*i)->overwrite_existing_buffers ();
                }
                if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
                        finished = false;
                        return;
                }
        }
}


void
Session::non_realtime_locate ()
{
        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                (*i)->non_realtime_locate (_transport_frame);
        }
}


void
Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
{
        struct tm* now;
        time_t     xnow;
        bool       did_record;
        bool       saved;
        PostTransportWork ptw = post_transport_work();

        did_record = false;
        saved = false;

        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                if ((*i)->get_captured_frames () != 0) {
                        did_record = true;
                        break;
                }
        }

        /* stop and locate are merged here because they share a lot of common stuff */

        time (&xnow);
        now = localtime (&xnow);

        if (auditioner) {
                auditioner->cancel_audition ();
        }

        clear_clicks();
        cumulative_rf_motion = 0;
        reset_rf_scale (0);

        if (did_record) {
                begin_reversible_command ("capture");

                Location* loc = _locations.session_range_location();
                bool change_end = false;

                if (_transport_frame < loc->end()) {

                        /* stopped recording before current end */

                        if (config.get_end_marker_is_free()) {

                                /* first capture for this session, move end back to where we are */

                                change_end = true;
                        }

                } else if (_transport_frame > loc->end()) {

                        /* stopped recording after the current end, extend it */

                        change_end = true;
                }

                if (change_end) {
                        XMLNode &before = loc->get_state();
                        loc->set_end(_transport_frame);
                        XMLNode &after = loc->get_state();
                        add_command (new MementoCommand<Location>(*loc, &before, &after));
                }

                config.set_end_marker_is_free (false);
                _have_captured = true;
        }

        DEBUG_TRACE (DEBUG::Transport, X_("Butler PTW: DS stop\n"));
        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                (*i)->transport_stopped (*now, xnow, abort);
        }

        boost::shared_ptr<RouteList> r = routes.reader ();

        for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
                if (!(*i)->is_hidden()) {
                        (*i)->set_pending_declick (0);
                }
        }

        if (did_record) {
                commit_reversible_command ();
        }

        if (_engine.running()) {
                update_latency_compensation (true, abort);
        }

        bool const auto_return_enabled =
                (!config.get_external_sync() && config.get_auto_return());

        if (auto_return_enabled ||
            (ptw & PostTransportLocate) ||
            (_requested_return_frame >= 0) ||
            synced_to_jack()) {

                if (pending_locate_flush) {
                        flush_all_inserts ();
                }

                if ((auto_return_enabled || synced_to_jack() || _requested_return_frame >= 0) &&
                    !(ptw & PostTransportLocate)) {

                        /* no explicit locate queued */

                        bool do_locate = false;

                        if (_requested_return_frame >= 0) {

                                /* explicit return request pre-queued in event list. overrides everything else */
                                
                                cerr << "explicit auto-return to " << _requested_return_frame << endl;

                                _transport_frame = _requested_return_frame;
                                do_locate = true;

                        } else {
                                if (config.get_auto_return()) {

                                        if (play_loop) {

                                                /* don't try to handle loop play when synced to JACK */

                                                if (!synced_to_jack()) {

                                                        Location *location = _locations.auto_loop_location();
                                                        
                                                        if (location != 0) {
                                                                _transport_frame = location->start();
                                                        } else {
                                                                _transport_frame = _last_roll_location;
                                                        }
                                                        do_locate = true;
                                                }

                                        } else if (_play_range) {

                                                /* return to start of range */

                                                if (!current_audio_range.empty()) {
                                                        _transport_frame = current_audio_range.front().start;
                                                        do_locate = true;
                                                }

                                        } else {
                                                
                                                /* regular auto-return */
                                                
                                                _transport_frame = _last_roll_location;
                                                do_locate = true;
                                        }
                                } 
                        }

                        _requested_return_frame = -1;                   

                        if (do_locate) {
                                _engine.transport_locate (_transport_frame);
                        }
                } 

        }

        /* do this before seeking, because otherwise the Diskstreams will do the wrong thing in seamless loop mode.
        */

        if (ptw & PostTransportClearSubstate) {
                _play_range = false;
                unset_play_loop ();
        }

        /* this for() block can be put inside the previous if() and has the effect of ... ??? what */


        DEBUG_TRACE (DEBUG::Transport, X_("Butler PTW: locate\n"));

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                if (!(*i)->hidden()) {
                        DEBUG_TRACE (DEBUG::Transport, string_compose ("Butler PTW: locate on %1\n", (*i)->name()));
                        (*i)->non_realtime_locate (_transport_frame);
                }

                if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
                        finished = false;
                        /* we will be back */
                        return;
                }
        }

        have_looped = false;

        send_full_time_code (0);
        deliver_mmc (MIDI::MachineControl::cmdStop, 0);
        deliver_mmc (MIDI::MachineControl::cmdLocate, _transport_frame);

        if ((ptw & PostTransportLocate) && get_record_enabled()) {
                /* capture start has been changed, so save pending state */
                save_state ("", true);
                saved = true;
        }

        /* always try to get rid of this */

        remove_pending_capture_state ();

        /* save the current state of things if appropriate */

        if (did_record && !saved) {
                save_state (_current_snapshot_name);
        }

        if (ptw & PostTransportDuration) {
                DurationChanged (); /* EMIT SIGNAL */
        }

        if (ptw & PostTransportStop) {
                _play_range = false;
                play_loop = false;
        }

        // can't cast away volatile so copy and emit that
        nframes64_t tframe = _transport_frame;
        PositionChanged (tframe); /* EMIT SIGNAL */
        TransportStateChange (); /* EMIT SIGNAL */

        /* and start it up again if relevant */

        if ((ptw & PostTransportLocate) && !config.get_external_sync() && pending_locate_roll) {
                request_transport_speed (1.0);
                pending_locate_roll = false;
        }
}

void
Session::check_declick_out ()
{
        bool locate_required = transport_sub_state & PendingLocate;

        /* this is called after a process() iteration. if PendingDeclickOut was set,
           it means that we were waiting to declick the output (which has just been
           done) before doing something else. this is where we do that "something else".

           note: called from the audio thread.
        */

        if (transport_sub_state & PendingDeclickOut) {

                if (locate_required) {
                        start_locate (pending_locate_frame, pending_locate_roll, pending_locate_flush);
                        transport_sub_state &= ~(PendingDeclickOut|PendingLocate);
                } else {
                        stop_transport (pending_abort);
                        transport_sub_state &= ~(PendingDeclickOut|PendingLocate);
                }
        }
}

void
Session::unset_play_loop ()
{
        play_loop = false;
        clear_events (SessionEvent::AutoLoop);
        
        // set all diskstreams to NOT use internal looping
        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                if (!(*i)->hidden()) {
                        (*i)->set_loop (0);
                }
        }
}

void
Session::set_play_loop (bool yn)
{
        /* Called from event-handling context */

        Location *loc;

        if (yn == play_loop || (actively_recording() && yn) || (loc = _locations.auto_loop_location()) == 0) {
                /* nothing to do, or can't change loop status while recording */
                return;
        }
        
        set_dirty();
        
        if (yn && Config->get_seamless_loop() && synced_to_jack()) {
                warning << string_compose (_("Seamless looping cannot be supported while %1 is using JACK transport.\n"
                                             "Recommend changing the configured options"), PROGRAM_NAME)
                        << endmsg;
                return;
        }
        
        if (yn) {

                play_loop = true;

                if (loc) {

                        unset_play_range ();

                        if (Config->get_seamless_loop()) {
                                // set all diskstreams to use internal looping
                                boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
                                for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                        if (!(*i)->hidden()) {
                                                (*i)->set_loop (loc);
                                        }
                                }
                        }
                        else {
                                // set all diskstreams to NOT use internal looping
                                boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
                                for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                        if (!(*i)->hidden()) {
                                                (*i)->set_loop (0);
                                        }
                                }
                        }
                        
                        /* put the loop event into the event list */
                        
                        SessionEvent* event = new SessionEvent (SessionEvent::AutoLoop, SessionEvent::Replace, loc->end(), loc->start(), 0.0f);
                        merge_event (event);

                        /* locate to start of loop and roll. If doing seamless loop, force a 
                           locate+buffer refill even if we are positioned there already.
                        */

                        start_locate (loc->start(), true, true, false, Config->get_seamless_loop());
                }

        } else {

                unset_play_loop ();
        }

        TransportStateChange ();
}
void
Session::flush_all_inserts ()
{
        boost::shared_ptr<RouteList> r = routes.reader ();

        for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
                (*i)->flush_processors ();
        }
}

void
Session::start_locate (nframes64_t target_frame, bool with_roll, bool with_flush, bool with_loop, bool force)
{
        if (synced_to_jack()) {

                double sp;
                nframes64_t pos;

                _slave->speed_and_position (sp, pos);

                if (target_frame != pos) {

                        /* tell JACK to change transport position, and we will
                           follow along later in ::follow_slave()
                        */

                        _engine.transport_locate (target_frame);

                        if (sp != 1.0f && with_roll) {
                                _engine.transport_start ();
                        }

                }

        } else {
                locate (target_frame, with_roll, with_flush, with_loop, force);
        }
}

int
Session::micro_locate (nframes_t distance)
{
        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                if (!(*i)->can_internal_playback_seek (distance)) {
                        return -1;
                }
        }

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                (*i)->internal_playback_seek (distance);
        }

        _transport_frame += distance;
        return 0;
}

void
Session::locate (nframes64_t target_frame, bool with_roll, bool with_flush, bool with_loop, bool force)
{
        if (actively_recording() && !with_loop) {
                return;
        }

        if (!force && _transport_frame == target_frame && !loop_changing && !with_loop) {
                if (with_roll) {
                        set_transport_speed (1.0, false);
                }
                loop_changing = false;
                return;
        }

        // Update Timecode time
        // [DR] FIXME: find out exactly where this should go below
        _transport_frame = target_frame;
        timecode_time(_transport_frame, transmitting_timecode_time);
        outbound_mtc_timecode_frame = _transport_frame;
        next_quarter_frame_to_send = 0;

        if (_transport_speed && (!with_loop || loop_changing)) {
                /* schedule a declick. we'll be called again when its done */

                if (!(transport_sub_state & PendingDeclickOut)) {
                        transport_sub_state |= (PendingDeclickOut|PendingLocate);
                        pending_locate_frame = target_frame;
                        pending_locate_roll = with_roll;
                        pending_locate_flush = with_flush;
                        return;
                }
        }

        if (transport_rolling() && (!auto_play_legal || !config.get_auto_play()) && !with_roll && !(synced_to_jack() && play_loop)) {
                realtime_stop (false, true); // XXX paul - check if the 2nd arg is really correct
        }

        if (force || !with_loop || loop_changing) {

                PostTransportWork todo = PostTransportLocate;

                if (with_roll) {
                        todo = PostTransportWork (todo | PostTransportRoll);
                } 

                add_post_transport_work (todo);
                _butler->schedule_transport_work ();

        } else {

                /* this is functionally what clear_clicks() does but with a tentative lock */

                Glib::RWLock::WriterLock clickm (click_lock, Glib::TRY_LOCK);

                if (clickm.locked()) {

                        for (Clicks::iterator i = clicks.begin(); i != clicks.end(); ++i) {
                                delete *i;
                        }

                        clicks.clear ();
                }
        }

        if (with_roll) {
                /* switch from input if we're going to roll */
                if (Config->get_monitoring_model() == HardwareMonitoring) {

                        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

                        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                if ((*i)->record_enabled ()) {
                                        //cerr << "switching from input" << __FILE__ << __LINE__ << endl << endl;
                                        (*i)->monitor_input (!config.get_auto_input());
                                }
                        }
                }
        } else {
                /* otherwise we're going to stop, so do the opposite */
                if (Config->get_monitoring_model() == HardwareMonitoring) {
                        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

                        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                if ((*i)->record_enabled ()) {
                                        //cerr << "switching to input" << __FILE__ << __LINE__ << endl << endl;
                                        (*i)->monitor_input (true);
                                }
                        }
                }
        }

        /* cancel looped playback if transport pos outside of loop range */
        if (play_loop) {
                Location* al = _locations.auto_loop_location();

                if (al && (_transport_frame < al->start() || _transport_frame > al->end())) {
                        // cancel looping directly, this is called from event handling context
                        set_play_loop (false);
                }
                else if (al && _transport_frame == al->start()) {
                        if (with_loop) {
                                // this is only necessary for seamless looping

                                boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

                                for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                        if ((*i)->record_enabled ()) {
                                                // tell it we've looped, so it can deal with the record state
                                                (*i)->transport_looped(_transport_frame);
                                        }
                                }
                        }
                        have_looped = true;
                        TransportLooped(); // EMIT SIGNAL
                }
        }

        loop_changing = false;

        _send_timecode_update = true;

        Located (); /* EMIT SIGNAL */
}

/** Set the transport speed.
 * @param speed New speed
 * @param abort
 */
void
Session::set_transport_speed (double speed, bool abort, bool clear_state)
{
        DEBUG_TRACE (DEBUG::Transport, string_compose ("Set transport speed to %1, abort = %2 clear_state = %3, current = %4\n", speed, abort, clear_state, _transport_speed));

        if (_transport_speed == speed) {
                return;
        }

        _target_transport_speed = fabs(speed);

        /* 8.0 max speed is somewhat arbitrary but based on guestimates regarding disk i/o capability
           and user needs. We really need CD-style "skip" playback for ffwd and rewind.
        */

        if (speed > 0) {
                speed = min (8.0, speed);
        } else if (speed < 0) {
                speed = max (-8.0, speed);
        }

        if (transport_rolling() && speed == 0.0) {

                /* we are rolling and we want to stop */

                if (Config->get_monitoring_model() == HardwareMonitoring)
                {
                        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

                        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                if ((*i)->record_enabled ()) {
                                        //cerr << "switching to input" << __FILE__ << __LINE__ << endl << endl;
                                        (*i)->monitor_input (true);
                                }
                        }
                }

                if (synced_to_jack ()) {
                        if (clear_state) {
                                /* do this here because our response to the slave won't 
                                   take care of it.
                                */
                                _play_range = false;
                                unset_play_loop ();
                        }
                        _engine.transport_stop ();
                } else {
                        stop_transport (abort);
                }

        } else if (transport_stopped() && speed == 1.0) {

                /* we are stopped and we want to start rolling at speed 1 */

                if (Config->get_monitoring_model() == HardwareMonitoring) {

                        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

                        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                if (config.get_auto_input() && (*i)->record_enabled ()) {
                                        //cerr << "switching from input" << __FILE__ << __LINE__ << endl << endl;
                                        (*i)->monitor_input (false);
                                }
                        }
                }

                if (synced_to_jack()) {
                        _engine.transport_start ();
                } else {
                        start_transport ();
                }

        } else {

                if ((synced_to_jack()) && speed != 0.0 && speed != 1.0) {
                        warning << string_compose (_("Global varispeed cannot be supported while %1 is connected to JACK transport control"),
                                                   PROGRAM_NAME)
                                << endmsg;
                        return;
                }

                if (actively_recording()) {
                        return;
                }

                if (speed > 0.0 && _transport_frame == current_end_frame()) {
                        return;
                }

                if (speed < 0.0 && _transport_frame == 0) {
                        return;
                }

                clear_clicks ();

                /* if we are reversing relative to the current speed, or relative to the speed
                   before the last stop, then we have to do extra work.
                */
                
                PostTransportWork todo = PostTransportWork (0);

                if ((_transport_speed && speed * _transport_speed < 0.0) || (_last_transport_speed * speed < 0.0) || (_last_transport_speed == 0.0f && speed < 0.0f)) {
                        todo = PostTransportWork (todo | PostTransportReverse);
                }

                _last_transport_speed = _transport_speed;
                _transport_speed = speed;

                boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
                for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                        if ((*i)->realtime_set_speed ((*i)->speed(), true)) {
                                todo = PostTransportWork (todo | PostTransportSpeed);
                                break;
                        }
                }

                if (todo) {
                        add_post_transport_work (todo);
                        _butler->schedule_transport_work ();
                }
        }
}


/** Stop the transport.  */
void
Session::stop_transport (bool abort, bool clear_state)
{
        if (_transport_speed == 0.0f) {
                return;
        }

        if (actively_recording() && !(transport_sub_state & StopPendingCapture) && _worst_output_latency > current_block_size) {

                boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

                for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                        (*i)->prepare_to_stop (_transport_frame);
                }

                /* we need to capture the audio that has still not yet been received by the system
                   at the time the stop is requested, so we have to roll past that time.

                   we want to declick before stopping, so schedule the autostop for one
                   block before the actual end. we'll declick in the subsequent block,
                   and then we'll really be stopped.
                */

                SessionEvent *ev = new SessionEvent (SessionEvent::StopOnce, SessionEvent::Replace,
                                       _transport_frame + _worst_output_latency - current_block_size,
                                       0, 0, abort);

                merge_event (ev);
                transport_sub_state |= StopPendingCapture;
                pending_abort = abort;
                return;
        }


        if ((transport_sub_state & PendingDeclickOut) == 0) {

                if (!(transport_sub_state & StopPendingCapture)) {
                        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
                        
                        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                                (*i)->prepare_to_stop (_transport_frame);
                        }
                }
                
                transport_sub_state |= PendingDeclickOut;
                /* we'll be called again after the declick */
                pending_abort = abort;
                return;
        }

        realtime_stop (abort, clear_state);
        _butler->schedule_transport_work ();
}

void
Session::start_transport ()
{
        _last_roll_location = _transport_frame;
        have_looped = false;

        /* if record status is Enabled, move it to Recording. if its
           already Recording, move it to Disabled.
        */

        switch (record_status()) {
        case Enabled:
                if (!config.get_punch_in()) {
                        enable_record ();
                }
                break;

        case Recording:
                if (!play_loop) {
                        disable_record (false);
                }
                break;

        default:
                break;
        }

        transport_sub_state |= PendingDeclickIn;

        _transport_speed = 1.0;
        _target_transport_speed = 1.0;

        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                (*i)->realtime_set_speed ((*i)->speed(), true);
        }

        deliver_mmc(MIDI::MachineControl::cmdDeferredPlay, _transport_frame);

        TransportStateChange (); /* EMIT SIGNAL */
}

/** Do any transport work in the audio thread that needs to be done after the
 * transport thread is finished.  Audio thread, realtime safe.
 */
void
Session::post_transport ()
{
        PostTransportWork ptw = post_transport_work ();

        if (ptw & PostTransportAudition) {
                if (auditioner && auditioner->auditioning()) {
                        process_function = &Session::process_audition;
                } else {
                        process_function = &Session::process_with_events;
                }
        }

        if (ptw & PostTransportStop) {

                transport_sub_state = 0;
        }

        if (ptw & PostTransportLocate) {

                if (((!config.get_external_sync() && (auto_play_legal && config.get_auto_play())) && !_exporting) || (ptw & PostTransportRoll)) {
                        start_transport ();

                } else {
                        transport_sub_state = 0;
                }
        }

        set_next_event ();
        /* XXX is this really safe? shouldn't we just be unsetting the bits that we actually
           know were handled ?
        */
        set_post_transport_work (PostTransportWork (0));
}

void
Session::reset_rf_scale (nframes_t motion)
{
        cumulative_rf_motion += motion;

        if (cumulative_rf_motion < 4 * _current_frame_rate) {
                rf_scale = 1;
        } else if (cumulative_rf_motion < 8 * _current_frame_rate) {
                rf_scale = 4;
        } else if (cumulative_rf_motion < 16 * _current_frame_rate) {
                rf_scale = 10;
        } else {
                rf_scale = 100;
        }

        if (motion != 0) {
                set_dirty();
        }
}

void
Session::use_sync_source (Slave* new_slave)
{
        /* Runs in process() context */

        bool non_rt_required = false;

        /* XXX this deletion is problematic because we're in RT context */

        delete _slave;
        _slave = new_slave;

        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                if (!(*i)->hidden()) {
                        if ((*i)->realtime_set_speed ((*i)->speed(), true)) {
                                non_rt_required = true;
                        }
                        (*i)->set_slaved (_slave != 0);
                }
        }

        if (non_rt_required) {
                add_post_transport_work (PostTransportSpeed);
                _butler->schedule_transport_work ();
        }

        set_dirty();
}

void
Session::drop_sync_source ()
{
        request_sync_source (0);
}

void
Session::switch_to_sync_source (SyncSource src)
{
        Slave* new_slave;

        DEBUG_TRACE (DEBUG::Slave, string_compose ("Setting up sync source %1\n", enum_2_string (src)));

        switch (src) {
        case MTC:
                if (_slave && dynamic_cast<MTC_Slave*>(_slave)) {
                        return;
                }

                if (_mtc_port) {
                        try {
                                new_slave = new MTC_Slave (*this, *_mtc_port);
                        }

                        catch (failed_constructor& err) {
                                return;
                        }

                } else {
                        error << _("No MTC port defined: MTC slaving is impossible.") << endmsg;
                        return;
                }
                break;

        case MIDIClock:
                if (_slave && dynamic_cast<MIDIClock_Slave*>(_slave)) {
                        return;
                }

                if (_midi_clock_port) {
                        try {
                                new_slave = new MIDIClock_Slave (*this, *_midi_clock_port, 24);
                        }

                        catch (failed_constructor& err) {
                                return;
                        }

                } else {
                        error << _("No MIDI Clock port defined: MIDI Clock slaving is impossible.") << endmsg;
                        return;
                }
                break;

        case JACK:
                if (_slave && dynamic_cast<JACK_Slave*>(_slave)) {
                        return;
                }

                new_slave = new JACK_Slave (_engine.jack());
                break;
                
        default:
                new_slave = 0;
                break;
        };

        request_sync_source (new_slave);
}

void
Session::reverse_diskstream_buffers ()
{
        add_post_transport_work (PostTransportReverse);
        _butler->schedule_transport_work ();
}

void
Session::set_diskstream_speed (Diskstream* stream, double speed)
{
        if (stream->realtime_set_speed (speed, false)) {
                add_post_transport_work (PostTransportSpeed);
                _butler->schedule_transport_work ();
                set_dirty ();
        }
}

void
Session::unset_play_range ()
{
        _play_range = false;
        _clear_event_type (SessionEvent::RangeStop);
        _clear_event_type (SessionEvent::RangeLocate);
}

void
Session::set_play_range (list<AudioRange>& range, bool leave_rolling)
{
        SessionEvent* ev;

        /* Called from event-processing context */

        unset_play_range ();
        
        if (range.empty()) {
                /* _play_range set to false in unset_play_range()
                 */
                if (!leave_rolling) {
                        /* stop transport */
                        SessionEvent* ev = new SessionEvent (SessionEvent::SetTransportSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0f, false);
                        merge_event (ev);
                }
                return;
        }

        _play_range = true;

        /* cancel loop play */
        unset_play_loop ();

        list<AudioRange>::size_type sz = range.size();
        
        if (sz > 1) {
                
                list<AudioRange>::iterator i = range.begin(); 
                list<AudioRange>::iterator next;
                
                while (i != range.end()) {
                        
                        next = i;
                        ++next;
                        
                        /* locating/stopping is subject to delays for declicking.
                         */
                        
                        nframes_t requested_frame = (*i).end;
                        
                        if (requested_frame > current_block_size) {
                                requested_frame -= current_block_size;
                        } else {
                                requested_frame = 0;
                        }
                        
                        if (next == range.end()) {
                                ev = new SessionEvent (SessionEvent::RangeStop, SessionEvent::Add, requested_frame, 0, 0.0f);
                        } else {
                                ev = new SessionEvent (SessionEvent::RangeLocate, SessionEvent::Add, requested_frame, (*next).start, 0.0f);
                        }
                        
                        merge_event (ev);
                        
                        i = next;
                }
                
        } else if (sz == 1) {

                ev = new SessionEvent (SessionEvent::RangeStop, SessionEvent::Add, range.front().end, 0, 0.0f);
                merge_event (ev);
                
        } 

        /* save range so we can do auto-return etc. */

        current_audio_range = range;

        /* now start rolling at the right place */

        ev = new SessionEvent (SessionEvent::LocateRoll, SessionEvent::Add, SessionEvent::Immediate, range.front().start, 0.0f, false);
        merge_event (ev);
        
        TransportStateChange ();
}

void
Session::request_bounded_roll (nframes_t start, nframes_t end)
{
        AudioRange ar (start, end, 0);
        list<AudioRange> lar;

        lar.push_back (ar);
        request_play_range (&lar, true);
}
void
Session::request_roll_at_and_return (nframes_t start, nframes_t return_to)
{
        SessionEvent *ev = new SessionEvent (SessionEvent::LocateRollLocate, SessionEvent::Add, SessionEvent::Immediate, return_to, 1.0);
        ev->target2_frame = start;
        queue_event (ev);
}

void
Session::engine_halted ()
{
        bool ignored;

        /* there will be no more calls to process(), so
           we'd better clean up for ourselves, right now.

           but first, make sure the butler is out of
           the picture.
        */

        g_atomic_int_set (&_butler->should_do_transport_work, 0);
        set_post_transport_work (PostTransportWork (0));
        _butler->stop ();

        realtime_stop (false, true);
        non_realtime_stop (false, 0, ignored);
        transport_sub_state = 0;

        TransportStateChange (); /* EMIT SIGNAL */
}


void
Session::xrun_recovery ()
{
        // can't cast away volatile so copy and emit that
        nframes64_t tframe = _transport_frame;
        Xrun (tframe); //EMIT SIGNAL

        if (Config->get_stop_recording_on_xrun() && actively_recording()) {

                /* it didn't actually halt, but we need
                   to handle things in the same way.
                */

                engine_halted();
        }
}

void
Session::route_processors_changed (RouteProcessorChange c)
{
        if (c.type == RouteProcessorChange::MeterPointChange) {
                return;
        }

        update_latency_compensation (false, false);
        resort_routes ();
}

void
Session::update_latency_compensation (bool with_stop, bool abort)
{
        bool update_jack = false;
        PostTransportWork ptw;

        if (_state_of_the_state & Deletion) {
                return;
        }

        _worst_track_latency = 0;
        ptw = post_transport_work();

#undef DEBUG_LATENCY
#ifdef DEBUG_LATENCY
        cerr << "\n---------------------------------\nUPDATE LATENCY\n";
#endif

        boost::shared_ptr<RouteList> r = routes.reader ();

        for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {

                if (with_stop) {
                        (*i)->handle_transport_stopped (abort, (ptw & PostTransportLocate), (!(ptw & PostTransportLocate) || pending_locate_flush));
                }

                nframes_t old_latency = (*i)->output()->signal_latency ();
                nframes_t track_latency = (*i)->update_total_latency ();

                if (old_latency != track_latency) {
                        (*i)->input()->update_port_total_latencies ();
                        (*i)->output()->update_port_total_latencies ();
                        update_jack = true;
                }

                if (!(*i)->is_hidden() && ((*i)->active())) {
                        _worst_track_latency = max (_worst_track_latency, track_latency);
                }
        }

        if (update_jack) {
                _engine.update_total_latencies ();
        }

#ifdef DEBUG_LATENCY
        cerr << "\tworst was " << _worst_track_latency << endl;
#endif

        for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
                (*i)->set_latency_delay (_worst_track_latency);
        }

        set_worst_io_latencies ();

        /* reflect any changes in latencies into capture offsets
        */

        boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();

        for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
                (*i)->set_capture_offset ();
        }
}

void
Session::allow_auto_play (bool yn)
{
        auto_play_legal = yn;
}

void
Session::reset_jack_connection (jack_client_t* jack)
{
        JACK_Slave* js;

        if (_slave && ((js = dynamic_cast<JACK_Slave*> (_slave)) != 0)) {
                js->reset_client (jack);
        }
}

bool
Session::maybe_stop (nframes_t limit)
{
       if ((_transport_speed > 0.0f && _transport_frame >= limit) || (_transport_speed < 0.0f && _transport_frame == 0)) {
               if (synced_to_jack () && config.get_jack_time_master ()) {
                       _engine.transport_stop ();
               } else if (!synced_to_jack ()) {
                       stop_transport ();
               }
               return true;
       }
       return false;
}