[ardour.git] / libs / ardour / io.cc

/*
    Copyright (C) 2000-2006 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 <fstream>
#include <algorithm>
#include <unistd.h>
#include <locale.h>
#include <errno.h>

#include <sigc++/bind.h>

#include <glibmm/thread.h>

#include <pbd/xml++.h>
#include <pbd/replace_all.h>

#include <ardour/audioengine.h>
#include <ardour/io.h>
#include <ardour/port.h>
#include <ardour/audio_port.h>
#include <ardour/midi_port.h>
#include <ardour/auto_bundle.h>
#include <ardour/session.h>
#include <ardour/cycle_timer.h>
#include <ardour/panner.h>
#include <ardour/buffer_set.h>
#include <ardour/meter.h>
#include <ardour/amp.h>

#include "i18n.h"

#include <cmath>

/*
  A bug in OS X's cmath that causes isnan() and isinf() to be 
  "undeclared". the following works around that
*/

#if defined(__APPLE__) && defined(__MACH__)
extern "C" int isnan (double);
extern "C" int isinf (double);
#endif

#define BLOCK_PROCESS_CALLBACK() Glib::Mutex::Lock em (_session.engine().process_lock())

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

const string                 IO::state_node_name = "IO";
bool                         IO::connecting_legal = false;
bool                         IO::ports_legal = false;
bool                         IO::panners_legal = false;
sigc::signal<void>           IO::Meter;
sigc::signal<int>            IO::ConnectingLegal;
sigc::signal<int>            IO::PortsLegal;
sigc::signal<int>            IO::PannersLegal;
sigc::signal<void,ChanCount> IO::PortCountChanged;
sigc::signal<int>            IO::PortsCreated;

Glib::StaticMutex IO::m_meter_signal_lock = GLIBMM_STATIC_MUTEX_INIT;

/* this is a default mapper of [0 .. 1.0] control values to a gain coefficient.
   others can be imagined. 
*/

#if 0
static gain_t direct_control_to_gain (double fract) { 
        /* XXX Marcus writes: this doesn't seem right to me. but i don't have a better answer ... */
        /* this maxes at +6dB */
        return pow (2.0,(sqrt(sqrt(sqrt(fract)))*198.0-192.0)/6.0);
}

static double direct_gain_to_control (gain_t gain) { 
        /* XXX Marcus writes: this doesn't seem right to me. but i don't have a better answer ... */
        if (gain == 0) return 0.0;
        
        return pow((6.0*log(gain)/log(2.0)+192.0)/198.0, 8.0);
}
#endif

/** @param default_type The type of port that will be created by ensure_io
 * and friends if no type is explicitly requested (to avoid breakage).
 */
IO::IO (Session& s, const string& name,
        int input_min, int input_max, int output_min, int output_max,
        DataType default_type)
        : Automatable (s, name),
      _output_buffers (new BufferSet()),
          _default_type (default_type),
          _input_minimum (ChanCount::ZERO),
          _input_maximum (ChanCount::INFINITE),
          _output_minimum (ChanCount::ZERO),
          _output_maximum (ChanCount::INFINITE)
{
        _panner = new Panner (name, _session);
        _meter = new PeakMeter (_session);

        if (input_min > 0) {
                _input_minimum = ChanCount(_default_type, input_min);
        }
        if (input_max >= 0) {
                _input_maximum = ChanCount(_default_type, input_max);
        }
        if (output_min > 0) {
                _output_minimum = ChanCount(_default_type, output_min);
        }
        if (output_max >= 0) {
                _output_maximum = ChanCount(_default_type, output_max);
        }

        _gain = 1.0;
        _desired_gain = 1.0;
        pending_state_node = 0;
        no_panner_reset = false;
        _phase_invert = false;
        deferred_state = 0;

        boost::shared_ptr<AutomationList> gl(
                        new AutomationList(Parameter(GainAutomation), 0.0, 2.0, 1.0));

        _gain_control = boost::shared_ptr<GainControl>(
                        new GainControl(X_("gaincontrol"), *this, gl));

        add_control(_gain_control);

        apply_gain_automation = false;
        
        {
                // IO::Meter is emitted from another thread so the
                // Meter signal must be protected.
                Glib::Mutex::Lock guard (m_meter_signal_lock);
                m_meter_connection = Meter.connect (mem_fun (*this, &IO::meter));
        }
        
        // Connect to our own PortCountChanged signal to connect output buffers
        IO::PortCountChanged.connect (mem_fun (*this, &IO::attach_buffers));

        _session.add_controllable (_gain_control);

        create_bundles_for_inputs_and_outputs ();
}

IO::IO (Session& s, const XMLNode& node, DataType dt)
        : Automatable (s, "unnamed io"),
      _output_buffers (new BufferSet()),
          _default_type (dt)
{
        _meter = new PeakMeter (_session);

        _panner = 0;
        deferred_state = 0;
        no_panner_reset = false;
        _desired_gain = 1.0;
        _gain = 1.0;

        apply_gain_automation = false;
        
        boost::shared_ptr<AutomationList> gl(
                        new AutomationList(Parameter(GainAutomation), 0.0, 2.0, 1.0));

        _gain_control = boost::shared_ptr<GainControl>(
                        new GainControl(X_("gaincontrol"), *this, gl));

        add_control(_gain_control);

        set_state (node);

        {
                // IO::Meter is emitted from another thread so the
                // Meter signal must be protected.
                Glib::Mutex::Lock guard (m_meter_signal_lock);
                m_meter_connection = Meter.connect (mem_fun (*this, &IO::meter));
        }
        
        // Connect to our own PortCountChanged signal to connect output buffers
        IO::PortCountChanged.connect (mem_fun (*this, &IO::attach_buffers));

        _session.add_controllable (_gain_control);

        create_bundles_for_inputs_and_outputs ();
}

IO::~IO ()
{
        cerr << "Deleting IO called " << _name << endl;

        Glib::Mutex::Lock guard (m_meter_signal_lock);
        
        Glib::Mutex::Lock lm (io_lock);

        for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                _session.engine().unregister_port (*i);
        }

        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                _session.engine().unregister_port (*i);
        }

        m_meter_connection.disconnect();

        delete _meter;
        delete _panner;
        delete _output_buffers;
}

void
IO::silence (nframes_t nframes, nframes_t offset)
{
        /* io_lock, not taken: function must be called from Session::process() calltree */

        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                i->get_buffer().silence (nframes, offset);
        }
}

/** Deliver bufs to the IO's Jack outputs.
 *
 * This function should automatically do whatever it necessary to correctly deliver bufs
 * to the outputs, eg applying gain or pan or whatever else needs to be done.
 */
void
IO::deliver_output (BufferSet& bufs, nframes_t start_frame, nframes_t end_frame, nframes_t nframes, nframes_t offset)
{
        // FIXME: type specific code doesn't actually need to be here, it will go away in time

        /* ********** AUDIO ********** */

        // Apply gain if gain automation isn't playing
        if ( ! apply_gain_automation) {
                
                gain_t dg = _gain; // desired gain

                {
                        Glib::Mutex::Lock dm (declick_lock, Glib::TRY_LOCK);

                        if (dm.locked()) {
                                dg = _desired_gain;
                        }

                }

                if (dg != _gain || dg != 1.0)
                        Amp::run_in_place(bufs, nframes, _gain, dg, _phase_invert);
        }
        
        // Use the panner to distribute audio to output port buffers
        if (_panner && !_panner->empty() && !_panner->bypassed()) {
                _panner->distribute (bufs, output_buffers(), start_frame, end_frame, nframes, offset);
        } else {
                const DataType type = DataType::AUDIO;
                
                // Copy any audio 1:1 to outputs
                
                BufferSet::iterator o = output_buffers().begin(type);
                BufferSet::iterator i = bufs.begin(type);
                BufferSet::iterator prev = i;
                
                while (i != bufs.end(type) && o != output_buffers().end (type)) {
                        o->read_from(*i, nframes, offset);
                        prev = i;
                        ++i;
                        ++o;
                }

                /* extra outputs get a copy of the last buffer */

                while (o != output_buffers().end(type)) {
                        o->read_from(*prev, nframes, offset);
                        ++o;
                }
        }

        /* ********** MIDI ********** */

        // No MIDI, we're done here
        if (bufs.count().n_midi() == 0) {
                return;
        }

        const DataType type = DataType::MIDI;

        // Copy any MIDI 1:1 to outputs
        assert(bufs.count().n_midi() == output_buffers().count().n_midi());
        BufferSet::iterator o = output_buffers().begin(type);
        for (BufferSet::iterator i = bufs.begin(type); i != bufs.end(type); ++i, ++o) {
                o->read_from(*i, nframes, offset);
        }
}

void
IO::collect_input (BufferSet& outs, nframes_t nframes, nframes_t offset)
{
        assert(outs.available() >= n_inputs());

        outs.set_count(n_inputs());
        
        if (outs.count() == ChanCount::ZERO)
                return;

        for (DataType::iterator t = DataType::begin(); t != DataType::end(); ++t) {
                
                BufferSet::iterator o = outs.begin(*t);
                for (PortSet::iterator i = _inputs.begin(*t); i != _inputs.end(*t); ++i, ++o) {
                        o->read_from(i->get_buffer(), nframes, offset);
                }

        }
}

void
IO::just_meter_input (nframes_t start_frame, nframes_t end_frame, 
                      nframes_t nframes, nframes_t offset)
{
        BufferSet& bufs = _session.get_scratch_buffers (n_inputs());

        collect_input (bufs, nframes, offset);

        _meter->run(bufs, start_frame, end_frame, nframes, offset);
}


void
IO::check_bundles_connected_to_inputs ()
{
        check_bundles (_bundles_connected_to_inputs, inputs());
}

void
IO::check_bundles_connected_to_outputs ()
{
        check_bundles (_bundles_connected_to_outputs, outputs());
}

void
IO::check_bundles (std::vector<UserBundleInfo>& list, const PortSet& ports)
{
        std::vector<UserBundleInfo> new_list;
        
        for (std::vector<UserBundleInfo>::iterator i = list.begin(); i != list.end(); ++i) {

                uint32_t const N = i->bundle->nchannels ();

                if (ports.num_ports() < N) {
                        continue;
                }

                bool ok = true;
                for (uint32_t j = 0; j < N; ++j) {
                        /* Every port on bundle channel j must be connected to our input j */
                        PortList const pl = i->bundle->channel_ports (j);
                        for (uint32_t k = 0; k < pl.size(); ++k) {
                                if (ports.port(j)->connected_to (pl[k]) == false) {
                                        ok = false;
                                        break;
                                }
                        }

                        if (ok == false) {
                                break;
                        }
                }

                if (ok) {
                        new_list.push_back (*i);
                } else {
                        i->configuration_will_change.disconnect ();
                        i->configuration_has_changed.disconnect ();
                        i->ports_will_change.disconnect ();
                        i->ports_have_changed.disconnect ();
                }
        }

        list = new_list;
}


int
IO::disconnect_input (Port* our_port, string other_port, void* src)
{
        if (other_port.length() == 0 || our_port == 0) {
                return 0;
        }

        { 
                BLOCK_PROCESS_CALLBACK ();
                
                {
                        Glib::Mutex::Lock lm (io_lock);
                        
                        /* check that our_port is really one of ours */
                        
                        if ( ! _inputs.contains(our_port)) {
                                return -1;
                        }
                        
                        /* disconnect it from the source */
                        
                        if (_session.engine().disconnect (other_port, our_port->name())) {
                                error << string_compose(_("IO: cannot disconnect input port %1 from %2"), our_port->name(), other_port) << endmsg;
                                return -1;
                        }

                        check_bundles_connected_to_inputs ();
                }
        }

        input_changed (ConnectionsChanged, src); /* EMIT SIGNAL */
        _session.set_dirty ();

        return 0;
}

int
IO::connect_input (Port* our_port, string other_port, void* src)
{
        if (other_port.length() == 0 || our_port == 0) {
                return 0;
        }

        {
                BLOCK_PROCESS_CALLBACK ();
                
                {
                        Glib::Mutex::Lock lm (io_lock);
                        
                        /* check that our_port is really one of ours */
                        
                        if ( ! _inputs.contains(our_port) ) {
                                return -1;
                        }
                        
                        /* connect it to the source */

                        if (_session.engine().connect (other_port, our_port->name())) {
                                return -1;
                        }
                }
        }

        input_changed (ConnectionsChanged, src); /* EMIT SIGNAL */
        _session.set_dirty ();
        return 0;
}

int
IO::disconnect_output (Port* our_port, string other_port, void* src)
{
        if (other_port.length() == 0 || our_port == 0) {
                return 0;
        }

        {
                BLOCK_PROCESS_CALLBACK ();
                
                {
                        Glib::Mutex::Lock lm (io_lock);
                        
                        /* check that our_port is really one of ours */
                        
                        if ( ! _outputs.contains(our_port) ) {
                                return -1;
                        }
                        
                        /* disconnect it from the destination */
                        
                        if (_session.engine().disconnect (our_port->name(), other_port)) {
                                error << string_compose(_("IO: cannot disconnect output port %1 from %2"), our_port->name(), other_port) << endmsg;
                                return -1;
                        }

                        check_bundles_connected_to_outputs ();
                }
        }

        output_changed (ConnectionsChanged, src); /* EMIT SIGNAL */
        _session.set_dirty ();
        return 0;
}

int
IO::connect_output (Port* our_port, string other_port, void* src)
{
        if (other_port.length() == 0 || our_port == 0) {
                return 0;
        }

        {
                BLOCK_PROCESS_CALLBACK ();

                
                {
                        Glib::Mutex::Lock lm (io_lock);
                        
                        /* check that our_port is really one of ours */
                        
                        if ( ! _outputs.contains(our_port) ) {
                                return -1;
                        }
                        
                        /* connect it to the destination */
                        
                        if (_session.engine().connect (our_port->name(), other_port)) {
                                return -1;
                        }
                }
        }

        output_changed (ConnectionsChanged, src); /* EMIT SIGNAL */
        _session.set_dirty ();
        return 0;
}

int
IO::set_input (Port* other_port, void* src)
{
        /* this removes all but one ports, and connects that one port
           to the specified source.
        */

        if (_input_minimum.n_total() > 1) {
                /* sorry, you can't do this */
                return -1;
        }

        if (other_port == 0) {
                if (_input_minimum == ChanCount::ZERO) {
                        return ensure_inputs (ChanCount::ZERO, false, true, src);
                } else {
                        return -1;
                }
        }

        if (ensure_inputs (ChanCount(other_port->type(), 1), true, true, src)) {
                return -1;
        }

        return connect_input (_inputs.port(0), other_port->name(), src);
}

int
IO::remove_output_port (Port* port, void* src)
{
        IOChange change (NoChange);

        {
                BLOCK_PROCESS_CALLBACK ();

                
                {
                        Glib::Mutex::Lock lm (io_lock);

                        if (n_outputs() <= _output_minimum) {
                                /* sorry, you can't do this */
                                return -1;
                        }

                        if (_outputs.remove(port)) {
                                change = IOChange (change|ConfigurationChanged);

                                if (port->connected()) {
                                        change = IOChange (change|ConnectionsChanged);
                                } 

                                _session.engine().unregister_port (*port);
                                check_bundles_connected_to_outputs ();
                                
                                setup_peak_meters ();
                                reset_panner ();
                        }
                }

                PortCountChanged (n_outputs()); /* EMIT SIGNAL */
        }

        if (change == ConnectionsChanged) {
                setup_bundles_for_inputs_and_outputs ();
        }

        if (change != NoChange) {
                output_changed (change, src);
                _session.set_dirty ();
                return 0;
        }

        return -1;
}

/** Add an output port.
 *
 * @param destination Name of input port to connect new port to.
 * @param src Source for emitted ConfigurationChanged signal.
 * @param type Data type of port.  Default value (NIL) will use this IO's default type.
 */
int
IO::add_output_port (string destination, void* src, DataType type)
{
        Port* our_port;
        char name[64];

        if (type == DataType::NIL)
                type = _default_type;

        {
                BLOCK_PROCESS_CALLBACK ();

                
                { 
                        Glib::Mutex::Lock lm (io_lock);
                        
                        if (n_outputs() >= _output_maximum) {
                                return -1;
                        }
                
                        /* Create a new output port */
                        
                        // FIXME: naming scheme for differently typed ports?
                        if (_output_maximum.get(type) == 1) {
                                snprintf (name, sizeof (name), _("%s/out"), _name.c_str());
                        } else {
                                snprintf (name, sizeof (name), _("%s/out %u"), _name.c_str(), find_output_port_hole());
                        }
                        
                        if ((our_port = _session.engine().register_output_port (Jack, type, name)) == 0) {
                                error << string_compose(_("IO: cannot register output port %1"), name) << endmsg;
                                return -1;
                        }
                        
                        _outputs.add (our_port);
                        setup_peak_meters ();
                        reset_panner ();
                }

                PortCountChanged (n_outputs()); /* EMIT SIGNAL */
        }

        if (destination.length()) {
                if (_session.engine().connect (our_port->name(), destination)) {
                        return -1;
                }
        }
        
        // pan_changed (src); /* EMIT SIGNAL */
        output_changed (ConfigurationChanged, src); /* EMIT SIGNAL */
        setup_bundles_for_inputs_and_outputs ();
        _session.set_dirty ();

        return 0;
}

int
IO::remove_input_port (Port* port, void* src)
{
        IOChange change (NoChange);

        {
                BLOCK_PROCESS_CALLBACK ();

                
                {
                        Glib::Mutex::Lock lm (io_lock);

                        if (n_inputs() <= _input_minimum) {
                                /* sorry, you can't do this */
                                return -1;
                        }

                        if (_inputs.remove(port)) {
                                change = IOChange (change|ConfigurationChanged);

                                if (port->connected()) {
                                        change = IOChange (change|ConnectionsChanged);
                                } 

                                _session.engine().unregister_port (*port);
                                check_bundles_connected_to_inputs ();
                                
                                setup_peak_meters ();
                                reset_panner ();
                        }
                }
                
                PortCountChanged (n_inputs ()); /* EMIT SIGNAL */
        }

        if (change == ConfigurationChanged) {
                setup_bundles_for_inputs_and_outputs ();
        }

        if (change != NoChange) {
                input_changed (change, src);
                _session.set_dirty ();
                return 0;
        } 
        
        return -1;
}


/** Add an input port.
 *
 * @param type Data type of port.  The appropriate Jack port type, and @ref Port will be created.
 * @param destination Name of input port to connect new port to.
 * @param src Source for emitted ConfigurationChanged signal.
 */
int
IO::add_input_port (string source, void* src, DataType type)
{
        Port* our_port;
        char name[64];
        
        if (type == DataType::NIL)
                type = _default_type;

        {
                BLOCK_PROCESS_CALLBACK ();
                
                { 
                        Glib::Mutex::Lock lm (io_lock);
                        
                        if (n_inputs() >= _input_maximum) {
                                return -1;
                        }

                        /* Create a new input port */
                        
                        // FIXME: naming scheme for differently typed ports?
                        if (_input_maximum.get(type) == 1) {
                                snprintf (name, sizeof (name), _("%s/in"), _name.c_str());
                        } else {
                                snprintf (name, sizeof (name), _("%s/in %u"), _name.c_str(), find_input_port_hole());
                        }

                        if ((our_port = _session.engine().register_input_port (Jack, type, name)) == 0) {
                                error << string_compose(_("IO: cannot register input port %1"), name) << endmsg;
                                return -1;
                        }

                        _inputs.add (our_port);
                        setup_peak_meters ();
                        reset_panner ();
                }

                PortCountChanged (n_inputs()); /* EMIT SIGNAL */
        }

        if (source.length()) {

                if (_session.engine().connect (source, our_port->name())) {
                        return -1;
                }
        } 

        // pan_changed (src); /* EMIT SIGNAL */
        input_changed (ConfigurationChanged, src); /* EMIT SIGNAL */
        setup_bundles_for_inputs_and_outputs ();
        _session.set_dirty ();
        
        return 0;
}

int
IO::disconnect_inputs (void* src)
{
        { 
                BLOCK_PROCESS_CALLBACK ();
                
                {
                        Glib::Mutex::Lock lm (io_lock);
                        
                        for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                                _session.engine().disconnect (*i);
                        }

                        check_bundles_connected_to_inputs ();
                }
        }
        
        input_changed (ConnectionsChanged, src); /* EMIT SIGNAL */
        
        return 0;
}

int
IO::disconnect_outputs (void* src)
{
        {
                BLOCK_PROCESS_CALLBACK ();
                
                {
                        Glib::Mutex::Lock lm (io_lock);
                        
                        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                                _session.engine().disconnect (*i);
                        }

                        check_bundles_connected_to_outputs ();
                }
        }

        output_changed (ConnectionsChanged, src); /* EMIT SIGNAL */
        _session.set_dirty ();
        
        return 0;
}

bool
IO::ensure_inputs_locked (ChanCount count, bool clear, void* src)
{
        Port* input_port = 0;
        bool  changed    = false;


        for (DataType::iterator t = DataType::begin(); t != DataType::end(); ++t) {
                
                const size_t n = count.get(*t);
        
                /* remove unused ports */
                for (size_t i = n_inputs().get(*t); i > n; --i) {
                        input_port = _inputs.port(*t, i-1);

                        assert(input_port);
                        _inputs.remove(input_port);
                        _session.engine().unregister_port (*input_port);

                        changed = true;
                }

                /* create any necessary new ports */
                while (n_inputs().get(*t) < n) {

                        char buf[64];

                        if (_input_maximum.get(*t) == 1) {
                                snprintf (buf, sizeof (buf), _("%s/in"), _name.c_str());
                        } else {
                                snprintf (buf, sizeof (buf), _("%s/in %u"), _name.c_str(), find_input_port_hole());
                        }

                        try {

                                if ((input_port = _session.engine().register_input_port (Jack, *t, buf)) == 0) {
                                        error << string_compose(_("IO: cannot register input port %1"), buf) << endmsg;
                                        return -1;
                                }
                        }

                        catch (AudioEngine::PortRegistrationFailure& err) {
                                setup_peak_meters ();
                                reset_panner ();
                                /* pass it on */
                                throw AudioEngine::PortRegistrationFailure();
                        }

                        _inputs.add (input_port);
                        changed = true;
                }
        }
        
        if (changed) {
                check_bundles_connected_to_inputs ();
                setup_peak_meters ();
                reset_panner ();
                PortCountChanged (n_inputs()); /* EMIT SIGNAL */
                _session.set_dirty ();
        }
        
        if (clear) {
                /* disconnect all existing ports so that we get a fresh start */
                for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                        _session.engine().disconnect (*i);
                }
        }

        return changed;
}

/** Attach output_buffers to port buffers.
 * 
 * Connected to IO's own PortCountChanged signal.
 */
void
IO::attach_buffers(ChanCount ignored)
{
        _output_buffers->attach_buffers(_outputs);
}

int
IO::ensure_io (ChanCount in, ChanCount out, bool clear, void* src)
{
        bool in_changed     = false;
        bool out_changed    = false;
        bool need_pan_reset = false;

        in = min (_input_maximum, in);

        out = min (_output_maximum, out);

        if (in == n_inputs() && out == n_outputs() && !clear) {
                return 0;
        }

        {
                BLOCK_PROCESS_CALLBACK ();
                Glib::Mutex::Lock lm (io_lock);

                Port* port;
                
                if (n_outputs() != out) {
                        need_pan_reset = true;
                }
                
                for (DataType::iterator t = DataType::begin(); t != DataType::end(); ++t) {

                        const size_t nin = in.get(*t);
                        const size_t nout = out.get(*t);

                        Port* output_port = 0;
                        Port* input_port = 0;

                        /* remove unused output ports */
                        for (size_t i = n_outputs().get(*t); i > nout; --i) {
                                output_port = _outputs.port(*t, i-1);

                                assert(output_port);
                                _outputs.remove(output_port);
                                _session.engine().unregister_port (*output_port);

                                out_changed = true;
                        }

                        /* remove unused input ports */
                        for (size_t i = n_inputs().get(*t); i > nin; --i) {
                                input_port = _inputs.port(*t, i-1);

                                assert(input_port);
                                _inputs.remove(input_port);
                                _session.engine().unregister_port (*input_port);

                                in_changed = true;
                        }

                        /* create any necessary new input ports */

                        while (n_inputs().get(*t) < nin) {

                                char buf[64];

                                /* Create a new input port */

                                if (_input_maximum.get(*t) == 1) {
                                        snprintf (buf, sizeof (buf), _("%s/in"), _name.c_str());
                                } else {
                                        snprintf (buf, sizeof (buf), _("%s/in %u"), _name.c_str(), find_input_port_hole());
                                }

                                try {
                                        if ((port = _session.engine().register_input_port (Jack, *t, buf)) == 0) {
                                                error << string_compose(_("IO: cannot register input port %1"), buf) << endmsg;
                                                return -1;
                                        }
                                }
                                
                                catch (AudioEngine::PortRegistrationFailure& err) {
                                        setup_peak_meters ();
                                        reset_panner ();
                                        /* pass it on */
                                        throw AudioEngine::PortRegistrationFailure();
                                }

                                _inputs.add (port);
                                in_changed = true;
                        }

                        /* create any necessary new output ports */

                        while (n_outputs().get(*t) < nout) {

                                char buf[64];

                                /* Create a new output port */

                                if (_output_maximum.get(*t) == 1) {
                                        snprintf (buf, sizeof (buf), _("%s/out"), _name.c_str());
                                } else {
                                        snprintf (buf, sizeof (buf), _("%s/out %u"), _name.c_str(), find_output_port_hole());
                                }

                                try { 
                                        if ((port = _session.engine().register_output_port (Jack, *t, buf)) == 0) {
                                                error << string_compose(_("IO: cannot register output port %1"), buf) << endmsg;
                                                return -1;
                                        }
                                }

                                catch (AudioEngine::PortRegistrationFailure& err) {
                                        setup_peak_meters ();
                                        reset_panner ();
                                        /* pass it on */
                                        throw AudioEngine::PortRegistrationFailure ();
                                }

                                _outputs.add (port);
                                out_changed = true;
                        }
                }
                
                if (clear) {
                        
                        /* disconnect all existing ports so that we get a fresh start */
                        
                        for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                                _session.engine().disconnect (*i);
                        }
                        
                        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                                _session.engine().disconnect (*i);
                        }
                }
                
                if (in_changed || out_changed) {
                        setup_peak_meters ();
                        reset_panner ();
                }
        }

        if (out_changed) {
                check_bundles_connected_to_outputs ();
                output_changed (ConfigurationChanged, src); /* EMIT SIGNAL */
        }
        
        if (in_changed) {
                check_bundles_connected_to_inputs ();
                input_changed (ConfigurationChanged, src); /* EMIT SIGNAL */
        }

        if (in_changed || out_changed) {
                PortCountChanged (max (n_outputs(), n_inputs())); /* EMIT SIGNAL */
                setup_bundles_for_inputs_and_outputs ();
                _session.set_dirty ();
        }

        return 0;
}

int
IO::ensure_inputs (ChanCount count, bool clear, bool lockit, void* src)
{
        bool changed = false;

        count = min (_input_maximum, count);

        if (count == n_inputs() && !clear) {
                return 0;
        }

        if (lockit) {
                BLOCK_PROCESS_CALLBACK ();
                Glib::Mutex::Lock im (io_lock);
                changed = ensure_inputs_locked (count, clear, src);
        } else {
                changed = ensure_inputs_locked (count, clear, src);
        }

        if (changed) {
                input_changed (ConfigurationChanged, src); /* EMIT SIGNAL */
                setup_bundles_for_inputs_and_outputs ();
                _session.set_dirty ();
        }
        return 0;
}

bool
IO::ensure_outputs_locked (ChanCount count, bool clear, void* src)
{
        Port* output_port    = 0;
        bool  changed        = false;
        bool  need_pan_reset = false;

        if (n_outputs() != count) {
                need_pan_reset = true;
        }
        
        for (DataType::iterator t = DataType::begin(); t != DataType::end(); ++t) {

                const size_t n = count.get(*t);

                /* remove unused ports */
                for (size_t i = n_outputs().get(*t); i > n; --i) {
                        output_port = _outputs.port(*t, i-1);

                        assert(output_port);
                        _outputs.remove(output_port);
                        _session.engine().unregister_port (*output_port);

                        changed = true;
                }

                /* create any necessary new ports */
                while (n_outputs().get(*t) < n) {

                        char buf[64];

                        if (_output_maximum.get(*t) == 1) {
                                snprintf (buf, sizeof (buf), _("%s/out"), _name.c_str());
                        } else {
                                snprintf (buf, sizeof (buf), _("%s/out %u"), _name.c_str(), find_output_port_hole());
                        }

                        if ((output_port = _session.engine().register_output_port (Jack, *t, buf)) == 0) {
                                error << string_compose(_("IO: cannot register output port %1"), buf) << endmsg;
                                return -1;
                        }

                        _outputs.add (output_port);
                        changed = true;
                        setup_peak_meters ();

                        if (need_pan_reset) {
                                reset_panner ();
                        }
                }
        }
        
        if (changed) {
                check_bundles_connected_to_outputs ();
                PortCountChanged (n_outputs()); /* EMIT SIGNAL */
                _session.set_dirty ();
        }
        
        if (clear) {
                /* disconnect all existing ports so that we get a fresh start */
                for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                        _session.engine().disconnect (*i);
                }
        }

        return changed;
}

int
IO::ensure_outputs (ChanCount count, bool clear, bool lockit, void* src)
{
        bool changed = false;

        if (_output_maximum < ChanCount::INFINITE) {
                count = min (_output_maximum, count);
                if (count == n_outputs() && !clear) {
                        return 0;
                }
        }

        /* XXX caller should hold io_lock, but generally doesn't */

        if (lockit) {
                BLOCK_PROCESS_CALLBACK ();
                Glib::Mutex::Lock im (io_lock);
                changed = ensure_outputs_locked (count, clear, src);
        } else {
                changed = ensure_outputs_locked (count, clear, src);
        }

        if (changed) {
                 output_changed (ConfigurationChanged, src); /* EMIT SIGNAL */
                 setup_bundles_for_inputs_and_outputs ();
        }

        return 0;
}

gain_t
IO::effective_gain () const
{
        if (_gain_control->list()->automation_playback()) {
                return _gain_control->get_value();
        } else {
                return _desired_gain;
        }
}

void
IO::reset_panner ()
{
        if (panners_legal) {
                if (!no_panner_reset) {
                        _panner->reset (n_outputs().n_audio(), pans_required());
                }
        } else {
                panner_legal_c.disconnect ();
                panner_legal_c = PannersLegal.connect (mem_fun (*this, &IO::panners_became_legal));
        }
}

int
IO::panners_became_legal ()
{
        _panner->reset (n_outputs().n_audio(), pans_required());
        _panner->load (); // automation
        panner_legal_c.disconnect ();
        return 0;
}

void
IO::defer_pan_reset ()
{
        no_panner_reset = true;
}

void
IO::allow_pan_reset ()
{
        no_panner_reset = false;
        reset_panner ();
}


XMLNode&
IO::get_state (void)
{
        return state (true);
}

XMLNode&
IO::state (bool full_state)
{
        XMLNode* node = new XMLNode (state_node_name);
        char buf[64];
        string str;
        LocaleGuard lg (X_("POSIX"));
        Glib::Mutex::Lock lm (io_lock);

        node->add_property("name", _name);
        id().print (buf, sizeof (buf));
        node->add_property("id", buf);

        for (
          std::vector<UserBundleInfo>::iterator i = _bundles_connected_to_inputs.begin();
          i != _bundles_connected_to_inputs.end();
          ++i
          )
        {
                XMLNode* n = new XMLNode ("InputBundle");
                n->add_property ("name", i->bundle->name ());
                node->add_child_nocopy (*n);
        }

        for (
          std::vector<UserBundleInfo>::iterator i = _bundles_connected_to_outputs.begin();
          i != _bundles_connected_to_outputs.end();
          ++i
          )
        {
                XMLNode* n = new XMLNode ("OutputBundle");
                n->add_property ("name", i->bundle->name ());
                node->add_child_nocopy (*n);
        }
        
        str = "";

        for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                        
                const char **connections = i->get_connections();
                
                if (connections && connections[0]) {
                        str += '{';
                        
                        for (int n = 0; connections && connections[n]; ++n) {
                                if (n) {
                                        str += ',';
                                }
                                
                                /* if its a connection to our own port,
                                   return only the port name, not the
                                   whole thing. this allows connections
                                   to be re-established even when our
                                   client name is different.
                                */
                                
                                str += _session.engine().make_port_name_relative (connections[n]);
                        }       
                        
                        str += '}';
                        
                        free (connections);
                }
                else {
                        str += "{}";
                }
        }
        
        node->add_property ("inputs", str);

        str = "";
        
        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                
                const char **connections = i->get_connections();
                
                if (connections && connections[0]) {
                        
                        str += '{';
                        
                        for (int n = 0; connections[n]; ++n) {
                                if (n) {
                                        str += ',';
                                }
                                
                                str += _session.engine().make_port_name_relative (connections[n]);
                        }
                        
                        str += '}';
                        
                        free (connections);
                }
                else {
                        str += "{}";
                }
        }
        
        node->add_property ("outputs", str);

        node->add_child_nocopy (_panner->state (full_state));
        node->add_child_nocopy (_gain_control->get_state ());

        snprintf (buf, sizeof(buf), "%2.12f", gain());
        node->add_property ("gain", buf);

        /* To make backwards compatibility a bit easier, write ChanCount::INFINITE to the session file
           as -1.
        */

        int const in_max = _input_maximum == ChanCount::INFINITE ? -1 : _input_maximum.get(_default_type);
        int const out_max = _output_maximum == ChanCount::INFINITE ? -1 : _output_maximum.get(_default_type);

        snprintf (buf, sizeof(buf)-1, "%d,%d,%d,%d", _input_minimum.get(_default_type), in_max, _output_minimum.get(_default_type), out_max);

        node->add_property ("iolimits", buf);

        /* automation */
        
        if (full_state)
                node->add_child_nocopy (get_automation_state());

        return *node;
}

int
IO::set_state (const XMLNode& node)
{
        const XMLProperty* prop;
        XMLNodeConstIterator iter;
        LocaleGuard lg (X_("POSIX"));

        /* force use of non-localized representation of decimal point,
           since we use it a lot in XML files and so forth.
        */

        if (node.name() != state_node_name) {
                error << string_compose(_("incorrect XML node \"%1\" passed to IO object"), node.name()) << endmsg;
                return -1;
        }

        if ((prop = node.property ("name")) != 0) {
                _name = prop->value();
                /* used to set panner name with this, but no more */
        } 

        if ((prop = node.property ("id")) != 0) {
                _id = prop->value ();
        }

        int in_min = -1;
        int in_max = -1;
        int out_min = -1;
        int out_max = -1;

        if ((prop = node.property ("iolimits")) != 0) {
                sscanf (prop->value().c_str(), "%d,%d,%d,%d",
                        &in_min, &in_max, &out_min, &out_max);

                /* Correct for the difference between the way we write things to session files and the
                   way things are described by ChanCount; see comments in io.h about what the different
                   ChanCount values mean. */

                if (in_min < 0) {
                        _input_minimum = ChanCount::ZERO;
                } else {
                        _input_minimum = ChanCount (_default_type, in_min);
                }

                if (in_max < 0) {
                        _input_maximum = ChanCount::INFINITE;
                } else {
                        _input_maximum = ChanCount (_default_type, in_max);
                }

                if (out_min < 0) {
                        _output_minimum = ChanCount::ZERO;
                } else {
                        _output_minimum = ChanCount (_default_type, out_min);
                }
                
                if (out_max < 0) {
                        _output_maximum = ChanCount::INFINITE;
                } else {
                        _output_maximum = ChanCount (_default_type, out_max);
                }
        }
        
        if ((prop = node.property ("gain")) != 0) {
                set_gain (atof (prop->value().c_str()), this);
                _gain = _desired_gain;
        }

        if ((prop = node.property ("automation-state")) != 0 || (prop = node.property ("automation-style")) != 0) {
                /* old school automation handling */
        }

        for (iter = node.children().begin(); iter != node.children().end(); ++iter) {

                if ((*iter)->name() == "Panner") {
                        if (_panner == 0) {
                                _panner = new Panner (_name, _session);
                        }
                        _panner->set_state (**iter);
                }

                if ((*iter)->name() == X_("Automation")) {

                        set_automation_state (*(*iter), Parameter(GainAutomation));
                }

                if ((*iter)->name() == X_("controllable")) {
                        if ((prop = (*iter)->property("name")) != 0 && prop->value() == "gaincontrol") {
                                _gain_control->set_state (**iter);
                        }
                }
        }

        if (ports_legal) {

                if (create_ports (node)) {
                        return -1;
                }

        } else {

                port_legal_c = PortsLegal.connect (mem_fun (*this, &IO::ports_became_legal));
        }

        if (panners_legal) {
                reset_panner ();
        } else {
                panner_legal_c = PannersLegal.connect (mem_fun (*this, &IO::panners_became_legal));
        }

        if (connecting_legal) {

                if (make_connections (node)) {
                        return -1;
                }

        } else {
                
                connection_legal_c = ConnectingLegal.connect (mem_fun (*this, &IO::connecting_became_legal));
        }

        if (!ports_legal || !connecting_legal) {
                pending_state_node = new XMLNode (node);
        }

        return 0;
}

int
IO::load_automation (string path)
{
        string fullpath;
        ifstream in;
        char line[128];
        uint32_t linecnt = 0;
        float version;
        LocaleGuard lg (X_("POSIX"));

        fullpath = _session.automation_dir();
        fullpath += path;

        in.open (fullpath.c_str());

        if (!in) {
                fullpath = _session.automation_dir();
                fullpath += _session.snap_name();
                fullpath += '-';
                fullpath += path;

                in.open (fullpath.c_str());

                if (!in) {
                        error << string_compose(_("%1: cannot open automation event file \"%2\""), _name, fullpath) << endmsg;
                        return -1;
                }
        }

        clear_automation ();

        while (in.getline (line, sizeof(line), '\n')) {
                char type;
                nframes_t when;
                double value;

                if (++linecnt == 1) {
                        if (memcmp (line, "version", 7) == 0) {
                                if (sscanf (line, "version %f", &version) != 1) {
                                        error << string_compose(_("badly formed version number in automation event file \"%1\""), path) << endmsg;
                                        return -1;
                                }
                        } else {
                                error << string_compose(_("no version information in automation event file \"%1\""), path) << endmsg;
                                return -1;
                        }

                        continue;
                }

                if (sscanf (line, "%c %" PRIu32 " %lf", &type, &when, &value) != 3) {
                        warning << string_compose(_("badly formatted automation event record at line %1 of %2 (ignored)"), linecnt, path) << endmsg;
                        continue;
                }

                switch (type) {
                case 'g':
                        _gain_control->list()->fast_simple_add (when, value);
                        break;

                case 's':
                        break;

                case 'm':
                        break;

                case 'p':
                        /* older (pre-1.0) versions of ardour used this */
                        break;

                default:
                        warning << _("dubious automation event found (and ignored)") << endmsg;
                }
        }

        return 0;
}

int
IO::connecting_became_legal ()
{
        int ret;

        if (pending_state_node == 0) {
                fatal << _("IO::connecting_became_legal() called without a pending state node") << endmsg;
                /*NOTREACHED*/
                return -1;
        }

        connection_legal_c.disconnect ();

        ret = make_connections (*pending_state_node);

        if (ports_legal) {
                delete pending_state_node;
                pending_state_node = 0;
        }

        return ret;
}
int
IO::ports_became_legal ()
{
        int ret;

        if (pending_state_node == 0) {
                fatal << _("IO::ports_became_legal() called without a pending state node") << endmsg;
                /*NOTREACHED*/
                return -1;
        }

        port_legal_c.disconnect ();

        ret = create_ports (*pending_state_node);

        if (connecting_legal) {
                delete pending_state_node;
                pending_state_node = 0;
        }

        return ret;
}

int
IO::create_ports (const XMLNode& node)
{
        XMLProperty const * prop;
        int num_inputs = 0;
        int num_outputs = 0;

        if ((prop = node.property ("inputs")) != 0) {
                num_inputs = count (prop->value().begin(), prop->value().end(), '{');
        } else if ((prop = node.property ("outputs")) != 0) {
                num_outputs = count (prop->value().begin(), prop->value().end(), '{');
        }

        no_panner_reset = true;

        // FIXME: audio-only
        if (ensure_io (ChanCount(DataType::AUDIO, num_inputs), ChanCount(DataType::AUDIO, num_outputs), true, this)) {
                error << string_compose(_("%1: cannot create I/O ports"), _name) << endmsg;
                return -1;
        }

        no_panner_reset = false;

        set_deferred_state ();

        PortsCreated();
        return 0;
}


int
IO::make_connections (const XMLNode& node)
{
        XMLProperty const * prop;
        
        if ((prop = node.property ("inputs")) != 0) {
                if (set_inputs (prop->value())) {
                        error << string_compose(_("improper input channel list in XML node (%1)"), prop->value()) << endmsg;
                        return -1;
                }
        }

                                
        if ((prop = node.property ("outputs")) != 0) {
                if (set_outputs (prop->value())) {
                        error << string_compose(_("improper output channel list in XML node (%1)"), prop->value()) << endmsg;
                        return -1;
                }
        }

        for (XMLNodeConstIterator i = node.children().begin(); i != node.children().end(); ++i) {

                if ((*i)->name() == "InputBundle") {
                        XMLProperty const * prop = (*i)->property ("name");
                        if (prop) {
                                boost::shared_ptr<Bundle> b = _session.bundle_by_name (prop->value());
                                if (b) {
                                        connect_input_ports_to_bundle (b, this);
                                } else {
                                        error << string_compose(_("Unknown bundle \"%1\" listed for input of %2"), prop->value(), _name) << endmsg;
                                }
                        }
                        
                } else if ((*i)->name() == "OutputBundle") {
                        XMLProperty const * prop = (*i)->property ("name");
                        if (prop) {
                                boost::shared_ptr<Bundle> b = _session.bundle_by_name (prop->value());
                                if (b) {
                                        connect_output_ports_to_bundle (b, this);
                                } else {
                                        error << string_compose(_("Unknown bundle \"%1\" listed for output of %2"), prop->value(), _name) << endmsg;
                                }
                        }
                }
        }
        
        return 0;
}

int
IO::set_inputs (const string& str)
{
        vector<string> ports;
        int i;
        int n;
        uint32_t nports;
        
        if ((nports = count (str.begin(), str.end(), '{')) == 0) {
                return 0;
        }

        // FIXME: audio-only
        if (ensure_inputs (ChanCount(DataType::AUDIO, nports), true, true, this)) {
                return -1;
        }

        string::size_type start, end, ostart;

        ostart = 0;
        start = 0;
        end = 0;
        i = 0;

        while ((start = str.find_first_of ('{', ostart)) != string::npos) {
                start += 1;

                if ((end = str.find_first_of ('}', start)) == string::npos) {
                        error << string_compose(_("IO: badly formed string in XML node for inputs \"%1\""), str) << endmsg;
                        return -1;
                }

                if ((n = parse_io_string (str.substr (start, end - start), ports)) < 0) {
                        error << string_compose(_("bad input string in XML node \"%1\""), str) << endmsg;

                        return -1;
                        
                } else if (n > 0) {

                        for (int x = 0; x < n; ++x) {
                                connect_input (input (i), ports[x], this);
                        }
                }

                ostart = end+1;
                i++;
        }

        return 0;
}

int
IO::set_outputs (const string& str)
{
        vector<string> ports;
        int i;
        int n;
        uint32_t nports;
        
        if ((nports = count (str.begin(), str.end(), '{')) == 0) {
                return 0;
        }

        // FIXME: audio-only
        if (ensure_outputs (ChanCount(DataType::AUDIO, nports), true, true, this)) {
                return -1;
        }

        string::size_type start, end, ostart;

        ostart = 0;
        start = 0;
        end = 0;
        i = 0;

        while ((start = str.find_first_of ('{', ostart)) != string::npos) {
                start += 1;

                if ((end = str.find_first_of ('}', start)) == string::npos) {
                        error << string_compose(_("IO: badly formed string in XML node for outputs \"%1\""), str) << endmsg;
                        return -1;
                }

                if ((n = parse_io_string (str.substr (start, end - start), ports)) < 0) {
                        error << string_compose(_("IO: bad output string in XML node \"%1\""), str) << endmsg;

                        return -1;
                        
                } else if (n > 0) {

                        for (int x = 0; x < n; ++x) {
                                connect_output (output (i), ports[x], this);
                        }
                }

                ostart = end+1;
                i++;
        }

        return 0;
}

int
IO::parse_io_string (const string& str, vector<string>& ports)
{
        string::size_type pos, opos;

        if (str.length() == 0) {
                return 0;
        }

        pos = 0;
        opos = 0;

        ports.clear ();

        while ((pos = str.find_first_of (',', opos)) != string::npos) {
                ports.push_back (str.substr (opos, pos - opos));
                opos = pos + 1;
        }
        
        if (opos < str.length()) {
                ports.push_back (str.substr(opos));
        }

        return ports.size();
}

int
IO::parse_gain_string (const string& str, vector<string>& ports)
{
        string::size_type pos, opos;

        pos = 0;
        opos = 0;
        ports.clear ();

        while ((pos = str.find_first_of (',', opos)) != string::npos) {
                ports.push_back (str.substr (opos, pos - opos));
                opos = pos + 1;
        }
        
        if (opos < str.length()) {
                ports.push_back (str.substr(opos));
        }

        return ports.size();
}

bool
IO::set_name (const string& str)
{
        if (str == _name) {
                return true;
        }
        
        /* replace all colons in the name. i wish we didn't have to do this */
        string name = str;

        if (replace_all (name, ":", "-")) {
                warning << _("you cannot use colons to name objects with I/O connections") << endmsg;
        }

        for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                string current_name = i->short_name();
                current_name.replace (current_name.find (_name), _name.length(), name);
                i->set_name (current_name);
        }

        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                string current_name = i->short_name();
                current_name.replace (current_name.find (_name), _name.length(), name);
                i->set_name (current_name);
        }

        bool const r = SessionObject::set_name(name);

        setup_bundles_for_inputs_and_outputs ();

        return r;
}

void
IO::set_input_minimum (ChanCount n)
{
        _input_minimum = n;
}

void
IO::set_input_maximum (ChanCount n)
{
        _input_maximum = n;
}

void
IO::set_output_minimum (ChanCount n)
{
        _output_minimum = n;
}

void
IO::set_output_maximum (ChanCount n)
{
        _output_maximum = n;
}

void
IO::set_port_latency (nframes_t nframes)
{
        Glib::Mutex::Lock lm (io_lock);

        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                i->set_latency (nframes);
        }
}

nframes_t
IO::output_latency () const
{
        nframes_t max_latency;
        nframes_t latency;

        max_latency = 0;

        /* io lock not taken - must be protected by other means */

        for (PortSet::const_iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                if ((latency = _session.engine().get_port_total_latency (*i)) > max_latency) {
                        max_latency = latency;
                }
        }

        return max_latency;
}

nframes_t
IO::input_latency () const
{
        nframes_t max_latency;
        nframes_t latency;

        max_latency = 0;

        /* io lock not taken - must be protected by other means */

        for (PortSet::const_iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                if ((latency = _session.engine().get_port_total_latency (*i)) > max_latency) {
                        max_latency = latency;
                } 
        }

        return max_latency;
}

int
IO::connect_input_ports_to_bundle (boost::shared_ptr<Bundle> c, void* src)
{
        {
                BLOCK_PROCESS_CALLBACK ();
                Glib::Mutex::Lock lm2 (io_lock);

                /* Connect to the bundle, not worrying about any connections
                   that are already made. */

                uint32_t const channels = c->nchannels ();
                
                for (uint32_t n = 0; n < channels; ++n) {
                        const PortList& pl = c->channel_ports (n);

                        for (PortList::const_iterator i = pl.begin(); i != pl.end(); ++i) {

                          if (!_inputs.port(n)->connected_to (*i)) {
                                        
                                        if (_session.engine().connect (*i, _inputs.port(n)->name())) {
                                                return -1;
                                        }
                                }
                                
                        }
                }

                /* If this is a UserBundle, make a note of what we've done */

                boost::shared_ptr<UserBundle> ub = boost::dynamic_pointer_cast<UserBundle> (c);
                if (ub) {

                        /* See if we already know about this one */
                        std::vector<UserBundleInfo>::iterator i = _bundles_connected_to_inputs.begin();
                        while (i != _bundles_connected_to_inputs.end() && i->bundle != ub) {
                                ++i;
                        }

                        if (i == _bundles_connected_to_inputs.end()) {
                                /* We don't, so make a note */
                                _bundles_connected_to_inputs.push_back (UserBundleInfo (this, ub));
                        }
                }
        }

        input_changed (IOChange (ConfigurationChanged|ConnectionsChanged), src); /* EMIT SIGNAL */
        return 0;
}

int
IO::connect_output_ports_to_bundle (boost::shared_ptr<Bundle> c, void* src)
{
        {
                BLOCK_PROCESS_CALLBACK ();
                Glib::Mutex::Lock lm2 (io_lock);

                /* Connect to the bundle, not worrying about any connections
                   that are already made. */

                uint32_t const channels = c->nchannels ();

                for (uint32_t n = 0; n < channels; ++n) {

                        const PortList& pl = c->channel_ports (n);

                        for (PortList::const_iterator i = pl.begin(); i != pl.end(); ++i) {

                                if (!_outputs.port(n)->connected_to (*i)) {
                                                
                                        if (_session.engine().connect (_outputs.port(n)->name(), *i)) {
                                                return -1;
                                        }
                                }
                        }
                }

                /* If this is a UserBundle, make a note of what we've done */

                boost::shared_ptr<UserBundle> ub = boost::dynamic_pointer_cast<UserBundle> (c);
                if (ub) {

                        /* See if we already know about this one */
                        std::vector<UserBundleInfo>::iterator i = _bundles_connected_to_outputs.begin();
                        while (i != _bundles_connected_to_outputs.end() && i->bundle != ub) {
                                ++i;
                        }

                        if (i == _bundles_connected_to_outputs.end()) {
                                /* We don't, so make a note */
                                _bundles_connected_to_outputs.push_back (UserBundleInfo (this, ub));
                        }
                }
        }

        output_changed (IOChange (ConnectionsChanged|ConfigurationChanged), src); /* EMIT SIGNAL */

        return 0;
}

int
IO::disable_connecting ()
{
        connecting_legal = false;
        return 0;
}

int
IO::enable_connecting ()
{
        connecting_legal = true;
        return ConnectingLegal ();
}

int
IO::disable_ports ()
{
        ports_legal = false;
        return 0;
}

int
IO::enable_ports ()
{
        ports_legal = true;
        return PortsLegal ();
}

int
IO::disable_panners (void)
{
        panners_legal = false;
        return 0;
}

int
IO::reset_panners ()
{
        panners_legal = true;
        return PannersLegal ();
}

void
IO::bundle_configuration_will_change ()
{
        //XXX
//      connect_input_ports_to_bundle (_input_bundle, this);
}

void
IO::bundle_configuration_has_changed ()
{
        //XXX
//      connect_input_ports_to_bundle (_input_bundle, this);
}

void
IO::bundle_ports_will_change (int ignored)
{
//XXX
//      connect_output_ports_to_bundle (_output_bundle, this);
}

void
IO::bundle_ports_have_changed (int ignored)
{
        //XXX
//      connect_output_ports_to_bundle (_output_bundle, this);
}

void
IO::GainControl::set_value (float val)
{
        // max gain at about +6dB (10.0 ^ ( 6 dB * 0.05))
        if (val > 1.99526231f)
                val = 1.99526231f;

        _user_value = val;
        _io.set_gain (val, this);
        
        Changed(); /* EMIT SIGNAL */
}

float
IO::GainControl::get_value (void) const
{
        return AutomationControl::get_value();
}

void
IO::setup_peak_meters()
{
        ChanCount max_streams = std::max(_inputs.count(), _outputs.count());
        _meter->configure_io(max_streams, max_streams);
}

/**
    Update the peak meters.

    The meter signal lock is taken to prevent modification of the 
    Meter signal while updating the meters, taking the meter signal
    lock prior to taking the io_lock ensures that all IO will remain 
    valid while metering.
*/   
void
IO::update_meters()
{
    Glib::Mutex::Lock guard (m_meter_signal_lock);
    
    Meter(); /* EMIT SIGNAL */
}

void
IO::meter ()
{
        // FIXME: Ugly.  Meter should manage the lock, if it's necessary
        
        Glib::Mutex::Lock lm (io_lock); // READER: meter thread.
        _meter->meter();
}

void
IO::clear_automation ()
{
        Automatable::clear_automation (); // clears gain automation
        _panner->clear_automation ();
}

void
IO::set_parameter_automation_state (Parameter param, AutoState state)
{
        // XXX: would be nice to get rid of this special hack

        if (param.type() == GainAutomation) {

                bool changed = false;

                { 
                        Glib::Mutex::Lock lm (_automation_lock);

                        boost::shared_ptr<AutomationList> gain_auto = _gain_control->list();

                        if (state != gain_auto->automation_state()) {
                                changed = true;
                                _last_automation_snapshot = 0;
                                gain_auto->set_automation_state (state);

                                if (state != Off) {
                                        // FIXME: shouldn't this use Curve?
                                        set_gain (gain_auto->eval (_session.transport_frame()), this);
                                }
                        }
                }

                if (changed) {
                        _session.set_dirty ();
                }

        } else {
                Automatable::set_parameter_automation_state(param, state);
        }
}

void
IO::inc_gain (gain_t factor, void *src)
{
        if (_desired_gain == 0.0f)
                set_gain (0.000001f + (0.000001f * factor), src);
        else
                set_gain (_desired_gain + (_desired_gain * factor), src);
}

void
IO::set_gain (gain_t val, void *src)
{
        // max gain at about +6dB (10.0 ^ ( 6 dB * 0.05))
        if (val > 1.99526231f)
                val = 1.99526231f;

        if (src != _gain_control.get()) {
                _gain_control->set_value(val);
                // bit twisty, this will come back and call us again
                // (this keeps control in sync with reality)
                return;
        }

        {
                Glib::Mutex::Lock dm (declick_lock);
                _desired_gain = val;
        }

        if (_session.transport_stopped()) {
                _gain = val;
        }
        
        if (_session.transport_stopped() && src != 0 && src != this && _gain_control->list()->automation_write()) {
                _gain_control->list()->add (_session.transport_frame(), val);
                
        }

        _session.set_dirty();
}

void
IO::start_pan_touch (uint32_t which)
{
        if (which < _panner->size()) {
                (*_panner)[which]->pan_control()->list()->start_touch();
        }
}

void
IO::end_pan_touch (uint32_t which)
{
        if (which < _panner->size()) {
                (*_panner)[which]->pan_control()->list()->stop_touch();
        }

}

void
IO::automation_snapshot (nframes_t now)
{
        Automatable::automation_snapshot (now);

        if (_last_automation_snapshot > now || (now - _last_automation_snapshot) > _automation_interval) {
                _panner->snapshot (now);
        }
}

void
IO::transport_stopped (nframes_t frame)
{
        _gain_control->list()->reposition_for_rt_add (frame);

        if (_gain_control->list()->automation_state() != Off) {
                
                /* the src=0 condition is a special signal to not propagate 
                   automation gain changes into the mix group when locating.
                */

                // FIXME: shouldn't this use Curve?
                set_gain (_gain_control->list()->eval (frame), 0);
        }

        _panner->transport_stopped (frame);
}

int32_t
IO::find_input_port_hole ()
{
        /* CALLER MUST HOLD IO LOCK */

        uint32_t n;

        if (_inputs.empty()) {
                return 1;
        }

        for (n = 1; n < UINT_MAX; ++n) {
                char buf[jack_port_name_size()];
                PortSet::iterator i = _inputs.begin();

                snprintf (buf, jack_port_name_size(), _("%s/in %u"), _name.c_str(), n);

                for ( ; i != _inputs.end(); ++i) {
                        if (i->short_name() == buf) {
                                break;
                        }
                }

                if (i == _inputs.end()) {
                        break;
                }
        }
        return n;
}

int32_t
IO::find_output_port_hole ()
{
        /* CALLER MUST HOLD IO LOCK */

        uint32_t n;

        if (_outputs.empty()) {
                return 1;
        }

        for (n = 1; n < UINT_MAX; ++n) {
                char buf[jack_port_name_size()];
                PortSet::iterator i = _outputs.begin();

                snprintf (buf, jack_port_name_size(), _("%s/out %u"), _name.c_str(), n);

                for ( ; i != _outputs.end(); ++i) {
                        if (i->short_name() == buf) {
                                break;
                        }
                }

                if (i == _outputs.end()) {
                        break;
                }
        }
        
        return n;
}

AudioPort*
IO::audio_input(uint32_t n) const
{
        return dynamic_cast<AudioPort*>(input(n));
}

AudioPort*
IO::audio_output(uint32_t n) const
{
        return dynamic_cast<AudioPort*>(output(n));
}

MidiPort*
IO::midi_input(uint32_t n) const
{
        return dynamic_cast<MidiPort*>(input(n));
}

MidiPort*
IO::midi_output(uint32_t n) const
{
        return dynamic_cast<MidiPort*>(output(n));
}

void
IO::set_phase_invert (bool yn, void *src)
{
        if (_phase_invert != yn) {
                _phase_invert = yn;
                //  phase_invert_changed (src); /* EMIT SIGNAL */
        }
}

void
IO::set_denormal_protection (bool yn, void *src)
{
        if (_denormal_protection != yn) {
                _denormal_protection = yn;
                //  denormal_protection_changed (src); /* EMIT SIGNAL */
        }
}

void
IO::update_port_total_latencies ()
{
        /* io_lock, not taken: function must be called from Session::process() calltree */

        for (PortSet::iterator i = _inputs.begin(); i != _inputs.end(); ++i) {
                _session.engine().update_total_latency (*i);
        }

        for (PortSet::iterator i = _outputs.begin(); i != _outputs.end(); ++i) {
                _session.engine().update_total_latency (*i);
        }
}


/**
 *  Setup bundles that describe our inputs and outputs.
 */

void
IO::setup_bundles_for_inputs_and_outputs ()
{
        char buf[32];

        snprintf(buf, sizeof (buf), _("%s in"), _name.c_str());
        _bundle_for_inputs->set_name (buf);
        uint32_t const ni = inputs().num_ports();
        _bundle_for_inputs->set_channels (ni);
        for (uint32_t i = 0; i < ni; ++i) {
                _bundle_for_inputs->set_port (i, inputs().port(i)->name());
        }

        snprintf(buf, sizeof (buf), _("%s out"), _name.c_str());
        _bundle_for_outputs->set_name (buf);
        uint32_t const no = outputs().num_ports();
        _bundle_for_outputs->set_channels (no);
        for (uint32_t i = 0; i < no; ++i) {
                _bundle_for_outputs->set_port (i, outputs().port(i)->name());
        }
}


/**
 *  Create and setup bundles that describe our inputs and outputs.
 */

void
IO::create_bundles_for_inputs_and_outputs ()
{
        _bundle_for_inputs = boost::shared_ptr<AutoBundle> (new AutoBundle (true));
        _bundle_for_outputs = boost::shared_ptr<AutoBundle> (new AutoBundle (false));
        setup_bundles_for_inputs_and_outputs ();
}

/** Add a bundle to a list if is connected to our inputs.
 *  @param b Bundle to check.
 *  @param bundles List to add to.
 */
void
IO::maybe_add_input_bundle_to_list (boost::shared_ptr<Bundle> b, std::vector<boost::shared_ptr<Bundle> >* bundles)
{
        boost::shared_ptr<AutoBundle> ab = boost::dynamic_pointer_cast<AutoBundle, Bundle> (b);
        if (ab == 0 || ab->ports_are_outputs() == false) {
                return;
        }

        if (ab->nchannels () != n_inputs().n_total ()) {
                return;
        }

        for (uint32_t i = 0; i < n_inputs().n_total (); ++i) {

                PortList const & pl = b->channel_ports (i);

                if (pl.empty()) {
                        return;
                }

                if (!input(i)->connected_to (pl[0])) {
                        return;
                }
        }

        bundles->push_back (b);
}

/** @return Bundles connected to our inputs */
std::vector<boost::shared_ptr<Bundle> >
IO::bundles_connected_to_inputs ()
{
        std::vector<boost::shared_ptr<Bundle> > bundles;
        
        /* User bundles */
        for (std::vector<UserBundleInfo>::iterator i = _bundles_connected_to_inputs.begin(); i != _bundles_connected_to_inputs.end(); ++i) {
                bundles.push_back (i->bundle);
        }

        /* Auto bundles */
        _session.foreach_bundle (
                sigc::bind (sigc::mem_fun (*this, &IO::maybe_add_input_bundle_to_list), &bundles)
                );

        return bundles;
}


/** Add a bundle to a list if is connected to our outputs.
 *  @param b Bundle to check.
 *  @param bundles List to add to.
 */
void
IO::maybe_add_output_bundle_to_list (boost::shared_ptr<Bundle> b, std::vector<boost::shared_ptr<Bundle> >* bundles)
{
        boost::shared_ptr<AutoBundle> ab = boost::dynamic_pointer_cast<AutoBundle, Bundle> (b);
        if (ab == 0 || ab->ports_are_inputs() == false) {
                return;
        }

        if (ab->nchannels () != n_outputs().n_total ()) {
                return;
        }

        for (uint32_t i = 0; i < n_outputs().n_total (); ++i) {

                PortList const & pl = b->channel_ports (i);

                if (pl.empty()) {
                        return;
                }

                if (!output(i)->connected_to (pl[0])) {
                        return;
                }
        }

        bundles->push_back (b);
}


/* @return Bundles connected to our outputs */
std::vector<boost::shared_ptr<Bundle> >
IO::bundles_connected_to_outputs ()
{
        std::vector<boost::shared_ptr<Bundle> > bundles;

        /* User bundles */
        for (std::vector<UserBundleInfo>::iterator i = _bundles_connected_to_outputs.begin(); i != _bundles_connected_to_outputs.end(); ++i) {
                bundles.push_back (i->bundle);
        }

        /* Auto bundles */
        _session.foreach_bundle (
                sigc::bind (sigc::mem_fun (*this, &IO::maybe_add_output_bundle_to_list), &bundles)
                );

        return bundles; 
}


IO::UserBundleInfo::UserBundleInfo (IO* io, boost::shared_ptr<UserBundle> b)
{
        bundle = b;
        configuration_will_change = b->ConfigurationWillChange.connect (
                sigc::mem_fun (*io, &IO::bundle_configuration_will_change)
                );
        configuration_has_changed = b->ConfigurationHasChanged.connect (
                sigc::mem_fun (*io, &IO::bundle_configuration_has_changed)
                );
        ports_will_change = b->PortsWillChange.connect (
                sigc::mem_fun (*io, &IO::bundle_ports_will_change)
                );
        ports_have_changed = b->PortsHaveChanged.connect (
                sigc::mem_fun (*io, &IO::bundle_ports_have_changed)
                );
}