libmidi++: split apart "base-y" aspects of MIDI::Port into MIDI::PortBase and make MIDI::Port derive from it. This actually makes MIDI::Port effectively into MIDI::JackPort, but i'm not interested in the name changing at that level at this moment in time

git-svn-id: svn://localhost/ardour2/branches/3.0@12064 d708f5d6-7413-0410-9779-e7cbd77b26cf

9 files changed, 393 insertions, 198 deletions

diff --git a/libs/midi++2/channel.cc b/libs/midi++2/channel.cc
index ae889058c4..0c9fbe39d1 100644
--- a/libs/midi++2/channel.cc
+++ b/libs/midi++2/channel.cc
@@ -25,7 +25,8 @@
 
 using namespace MIDI;
 
-Channel::Channel (byte channelnum, Port &p) : _port (p)
+Channel::Channel (byte channelnum, PortBase &p) 
+	: _port (p)
 {
 	_channel_number = channelnum;
 
diff --git a/libs/midi++2/midi++/channel.h b/libs/midi++2/midi++/channel.h
index 162eea1e9a..370a569156 100644
--- a/libs/midi++2/midi++/channel.h
+++ b/libs/midi++2/midi++/channel.h
@@ -39,9 +39,9 @@ class Port;
 class Channel : public PBD::ScopedConnectionList {
 
   public:
-	Channel (byte channel_number, Port &);
+	Channel (byte channel_number, PortBase &);
 
-	Port &midi_port()               { return _port; }
+	PortBase &midi_port()           { return _port; }
 	byte channel()                  { return _channel_number; }
 	byte program()                  { return _program_number; }
 	byte bank()                     { return _bank_number; }
@@ -111,11 +111,11 @@ class Channel : public PBD::ScopedConnectionList {
 	}
 
   protected:
-	friend class Port;
+	friend class PortBase;
 	void connect_signals ();
 
   private:
-	Port & _port;
+	PortBase& _port;
 
 	/* Current channel values */
 	byte               _channel_number;
diff --git a/libs/midi++2/midi++/parser.h b/libs/midi++2/midi++/parser.h
index e57323e72d..ac452798cc 100644
--- a/libs/midi++2/midi++/parser.h
+++ b/libs/midi++2/midi++/parser.h
@@ -29,7 +29,7 @@
 
 namespace MIDI {
 
-class Port;
+class PortBase;
 class Parser;
 
 typedef PBD::Signal1<void,Parser&>                   ZeroByteSignal;
@@ -41,7 +41,7 @@ typedef PBD::Signal3<void,Parser &, byte *, size_t>  Signal;
 
 class Parser {
  public:
-	Parser (Port &p);
+	Parser (PortBase &p);
 	~Parser ();
 
 	/* sets the time that will be reported for any MTC or MIDI Clock
@@ -105,7 +105,7 @@ class Parser {
 	const char *midi_event_type_name (MIDI::eventType);
 	void trace (bool onoff, std::ostream *o, const std::string &prefix = "");
 	bool tracing() { return trace_stream != 0; }
-	Port &port() { return _port; }
+	PortBase &port() { return _port; }
 
 	void set_offline (bool);
 	bool offline() const { return _offline; }
@@ -136,9 +136,9 @@ class Parser {
 	void reset_mtc_state ();
 	
   private:
-	Port &_port;
+	PortBase&_port;
 	/* tracing */
-
+	
 	std::ostream *trace_stream;
 	std::string trace_prefix;
 	void trace_event (Parser &p, byte *msg, size_t len);
diff --git a/libs/midi++2/midi++/port.h b/libs/midi++2/midi++/port.h
index 6b4381d496..e7b532013e 100644
--- a/libs/midi++2/midi++/port.h
+++ b/libs/midi++2/midi++/port.h
@@ -34,98 +34,30 @@
 
 #include "midi++/types.h"
 #include "midi++/parser.h"
+#include "midi++/port_base.h"
 
 namespace MIDI {
 
 class Channel;
 class PortRequest;
 
-class Port {
+class Port : public PortBase {
   public:
-	enum Flags {
-		IsInput = JackPortIsInput,
-		IsOutput = JackPortIsOutput,
-	};
-	
-	Port (std::string const &, Flags, jack_client_t *);
+	Port (std::string const &, PortBase::Flags, jack_client_t *);
 	Port (const XMLNode&, jack_client_t *);
 	~Port ();
 
 	XMLNode& get_state () const;
 	void set_state (const XMLNode&);
 
-	// FIXME: make Manager a friend of port so these can be hidden?
-
-	/* Only for use by MidiManager.  Don't ever call this. */
 	void cycle_start (pframes_t nframes);
-	/* Only for use by MidiManager.  Don't ever call this. */
 	void cycle_end ();
 
-	/** Write a message to port.
-	 * @param msg Raw MIDI message to send
-	 * @param msglen Size of @a msg
-	 * @param timestamp Time stamp in frames of this message (relative to cycle start)
-	 * @return number of bytes successfully written
-	 */
+	void parse (framecnt_t timestamp);
 	int write (byte *msg, size_t msglen, timestamp_t timestamp);
-
-	/** Read raw bytes from a port.
-	 * @param buf memory to store read data in
-	 * @param bufsize size of @a buf
-	 * @return number of bytes successfully read, negative if error
-	 */
 	int read (byte *buf, size_t bufsize);
-
-	void parse (framecnt_t timestamp);
-	
-	/** Write a message to port.
-	 * @return true on success.
-	 * FIXME: describe semantics here
-	 */
-	int midimsg (byte *msg, size_t len, timestamp_t timestamp) {
-		return !(write (msg, len, timestamp) == (int) len);
-	} 
-
-	bool clock (timestamp_t timestamp);
-
-	/* select(2)/poll(2)-based I/O */
-
-	/** Get the file descriptor for port.
-	 * @return File descriptor, or -1 if not selectable. 
-	 */
-	int selectable () const {
-		return xthread.selectable();
-	}
-
-	Channel *channel (channel_t chn) { 
-		return _channel[chn&0x7F];
-	}
-	
-	Parser* parser () {
-		return _parser;
-	}
-	
-	const char *name () const   { return _tagname.c_str(); }
-	bool   ok ()   const        { return _ok; }
-
-	bool centrally_parsed() const { return _centrally_parsed; }
-	void set_centrally_parsed(bool yn) { _centrally_parsed = yn; }
-
-	bool receives_input () const {
-		return _flags == IsInput;
-	}
-
-	bool sends_output () const {
-		return _flags == IsOutput;
-	}
-
-	struct Descriptor {
-	    std::string tag;
-	    Flags flags;
-
-	    Descriptor (const XMLNode&);
-	    XMLNode& get_state();
-	};
+	void drain (int check_interval_usecs);
+	int selectable () const { return xthread.selectable(); }
 
 	pframes_t nframes_this_cycle() const { return _nframes_this_cycle; }
 
@@ -136,30 +68,19 @@ class Port {
 	static pthread_t get_process_thread () { return _process_thread; }
 	static bool is_process_thread();
 
-	static std::string state_node_name;
-	
 	static PBD::Signal0<void> MakeConnections;
 	static PBD::Signal0<void> JackHalted;
 
 private:	
-	bool              _ok;
 	bool              _currently_in_cycle;
 	pframes_t         _nframes_this_cycle;
-	std::string       _tagname;
-	size_t            _number;
-	Channel*          _channel[16];
-	Parser*           _parser;
 	jack_client_t*    _jack_client;
 	jack_port_t*      _jack_port;
-	framecnt_t        _last_read_index;
 	timestamp_t       _last_write_timestamp;
 	RingBuffer< Evoral::Event<double> > output_fifo;
 	Evoral::EventRingBuffer<timestamp_t> input_fifo;
 	Glib::Mutex output_fifo_lock;
 	CrossThreadChannel xthread;
-	Flags             _flags;
-	bool              _centrally_parsed;
-
 
 	int create_port ();
 
@@ -177,15 +98,6 @@ private:
 
 };
 
-struct PortSet {
-    PortSet (std::string str) : owner (str) { }
-    
-    std::string owner;
-    std::list<XMLNode> ports;
-};
-
-std::ostream & operator << ( std::ostream & os, const Port & port );
-
 } // namespace MIDI
 
 #endif // __libmidi_port_h__
diff --git a/libs/midi++2/midi++/port_base.h b/libs/midi++2/midi++/port_base.h
new file mode 100644
index 0000000000..ceb7834643
--- /dev/null
+++ b/libs/midi++2/midi++/port_base.h
@@ -0,0 +1,158 @@
+/*
+    Copyright (C) 1998-2010 Paul Barton-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.
+
+*/
+
+#ifndef  __libmidi_port_base_h__
+#define  __libmidi_port_base_h__
+
+#include <string>
+#include <iostream>
+
+#include <jack/types.h>
+
+#include "pbd/xml++.h"
+#include "pbd/crossthread.h"
+#include "pbd/signals.h"
+#include "pbd/ringbuffer.h"
+
+#include "evoral/Event.hpp"
+#include "evoral/EventRingBuffer.hpp"
+
+#include "midi++/types.h"
+#include "midi++/parser.h"
+
+namespace MIDI {
+
+class Channel;
+class PortRequest;
+
+class PortBase {
+  public:
+	enum Flags {
+		IsInput = JackPortIsInput,
+		IsOutput = JackPortIsOutput,
+	};
+	
+	PortBase (std::string const &, Flags);
+	PortBase (const XMLNode&);
+	virtual ~PortBase ();
+
+	XMLNode& get_state () const;
+	void set_state (const XMLNode&);
+
+	// FIXME: make Manager a friend of port so these can be hidden?
+
+	/* Only for use by MidiManager.  Don't ever call this. */
+	virtual void cycle_start (pframes_t nframes) {}
+	/* Only for use by MidiManager.  Don't ever call this. */
+	virtual void cycle_end () {}
+
+	/** Write a message to port.
+	 * @param msg Raw MIDI message to send
+	 * @param msglen Size of @a msg
+	 * @param timestamp Time stamp in frames of this message (relative to cycle start)
+	 * @return number of bytes successfully written
+	 */
+	virtual int write (byte *msg, size_t msglen, timestamp_t timestamp) = 0;
+
+	/** Read raw bytes from a port.
+	 * @param buf memory to store read data in
+	 * @param bufsize size of @a buf
+	 * @return number of bytes successfully read, negative if error
+	 */
+	virtual int read (byte *buf, size_t bufsize) = 0;
+
+	/** block until the output FIFO used by non-process threads
+	 * is empty, checking every @a check_interval_usecs usecs
+	 * for current status. Not to be called by a thread that
+	 * executes any part of a JACK process callback (will 
+	 * simply return immediately in that situation).
+	 */
+	virtual void drain (int check_interval_usecs) {}
+
+	/** Write a message to port.
+	 * @return true on success.
+	 * FIXME: describe semantics here
+	 */
+	int midimsg (byte *msg, size_t len, timestamp_t timestamp) {
+		return !(write (msg, len, timestamp) == (int) len);
+	} 
+
+	bool clock (timestamp_t timestamp);
+
+	/* select(2)/poll(2)-based I/O */
+
+	/** Get the file descriptor for port.
+	 * @return File descriptor, or -1 if not selectable. 
+	 */
+	virtual int selectable () const = 0;
+
+	Channel *channel (channel_t chn) { 
+		return _channel[chn&0x7F];
+	}
+	
+	Parser* parser () {
+		return _parser;
+	}
+	
+	const char *name () const   { return _tagname.c_str(); }
+	bool   ok ()   const        { return _ok; }
+
+	virtual bool centrally_parsed() const;
+	void set_centrally_parsed (bool yn) { _centrally_parsed = yn; }
+
+	bool receives_input () const {
+		return _flags == IsInput;
+	}
+
+	bool sends_output () const {
+		return _flags == IsOutput;
+	}
+
+	struct Descriptor {
+	    std::string tag;
+	    Flags flags;
+
+	    Descriptor (const XMLNode&);
+	    XMLNode& get_state();
+	};
+
+	static std::string state_node_name;
+
+  protected:
+	bool              _ok;
+	std::string       _tagname;
+	Channel*          _channel[16];
+	Parser*           _parser;
+	Flags             _flags;
+	bool              _centrally_parsed;
+
+	virtual void init (std::string const &, Flags);
+};
+
+struct PortSet {
+    PortSet (std::string str) : owner (str) { }
+    
+    std::string owner;
+    std::list<XMLNode> ports;
+};
+
+std::ostream & operator << (std::ostream& os, const PortBase& port);
+
+} // namespace MIDI
+
+#endif // __libmidi_port_base_h__
diff --git a/libs/midi++2/parser.cc b/libs/midi++2/parser.cc
index cdd23a5306..a56e3f82e4 100644
--- a/libs/midi++2/parser.cc
+++ b/libs/midi++2/parser.cc
@@ -30,7 +30,7 @@
 
 #include "midi++/types.h"
 #include "midi++/parser.h"
-#include "midi++/port.h"
+#include "midi++/port_base.h"
 #include "midi++/mmc.h"
 #include "pbd/transmitter.h"
 
@@ -104,9 +104,8 @@ Parser::midi_event_type_name (eventType t)
 	}
 }
 
-Parser::Parser (Port &p) 
-	: _port (p)
-
+Parser::Parser (PortBase &p) 
+	: _port(p)
 {
 	trace_stream = 0;
 	trace_prefix = "";
diff --git a/libs/midi++2/port.cc b/libs/midi++2/port.cc
index b5a16eef01..06db2e14b8 100644
--- a/libs/midi++2/port.cc
+++ b/libs/midi++2/port.cc
@@ -43,34 +43,30 @@ using namespace PBD;
 pthread_t Port::_process_thread;
 Signal0<void> Port::JackHalted;
 Signal0<void> Port::MakeConnections;
-string Port::state_node_name = "MIDI-port";
 
 Port::Port (string const & name, Flags flags, jack_client_t* jack_client)
-	: _currently_in_cycle (false)
+	: PortBase (name, flags)
+	, _currently_in_cycle (false)
 	, _nframes_this_cycle (0)
 	, _jack_client (jack_client)
 	, _jack_port (0)
-	, _last_read_index (0)
 	, output_fifo (512)
 	, input_fifo (1024)
 	, xthread (true)
-	, _flags (flags)
-	, _centrally_parsed (true)
 {
 	assert (jack_client);
 	init (name, flags);
 }
 
 Port::Port (const XMLNode& node, jack_client_t* jack_client)
-	: _currently_in_cycle (false)
+	: PortBase (node)
+	, _currently_in_cycle (false)
 	, _nframes_this_cycle (0)
 	, _jack_client (jack_client)
 	, _jack_port (0)
-	, _last_read_index (0)
 	, output_fifo (512)
 	, input_fifo (1024)
 	, xthread (true)
-	, _centrally_parsed (true)
 {
 	assert (jack_client);
 	
@@ -84,21 +80,7 @@ Port::Port (const XMLNode& node, jack_client_t* jack_client)
 void
 Port::init (string const & name, Flags flags)
 {
-	_ok = false;  /* derived class must set to true if constructor
-			 succeeds.
-		      */
-
-	_parser = 0;
-
-	_tagname = name;
-	_flags = flags;
-
-	_parser = new Parser (*this);
-
-	for (int i = 0; i < 16; i++) {
-		_channel[i] = new Channel (i, *this);
-		_channel[i]->connect_signals ();
-	}
+	PortBase::init (name, flags);
 
 	if (!create_port ()) {
 		_ok = true;
@@ -160,21 +142,6 @@ Port::parse (framecnt_t timestamp)
 	}
 }
 
-/** Send a clock tick message.
- * \return true on success.
- */
-bool
-Port::clock (timestamp_t timestamp)
-{
-	static byte clockmsg = 0xf8;
-	
-	if (sends_output()) {
-		return midimsg (&clockmsg, 1, timestamp);
-	}
-	
-	return false;
-}
-
 void
 Port::cycle_start (pframes_t nframes)
 {
@@ -184,8 +151,6 @@ Port::cycle_start (pframes_t nframes)
 	_nframes_this_cycle = nframes;
 
 	assert(_nframes_this_cycle == nframes);
-	_last_read_index = 0;
-	_last_write_timestamp = 0;
 
 	if (sends_output()) {
 		void *buffer = jack_port_get_buffer (_jack_port, nframes);
@@ -222,50 +187,30 @@ Port::cycle_end ()
 	_nframes_this_cycle = 0;
 }
 
-std::ostream & MIDI::operator << ( std::ostream & os, const MIDI::Port & port )
+void
+Port::jack_halted ()
 {
-	using namespace std;
-	os << "MIDI::Port { ";
-	os << "name: " << port.name();
-	os << "; ";
-	os << "ok: " << port.ok();
-	os << "; ";
-	os << " }";
-	return os;
+	_jack_client = 0;
+	_jack_port = 0;
 }
 
-Port::Descriptor::Descriptor (const XMLNode& node)
+void
+Port::drain (int check_interval_usecs)
 {
-	const XMLProperty *prop;
-	bool have_tag = false;
-	bool have_mode = false;
+	RingBuffer< Evoral::Event<double> >::rw_vector vec = { { 0, 0 }, { 0, 0} };
 
-	if ((prop = node.property ("tag")) != 0) {
-		tag = prop->value();
-		have_tag = true;
+	if (is_process_thread()) {
+		error << "Process thread called MIDI::Port::drain() - this cannot work" << endmsg;
+		return;
 	}
 
-	if ((prop = node.property ("mode")) != 0) {
-
-		if (strings_equal_ignore_case (prop->value(), "output") || strings_equal_ignore_case (prop->value(), "out")) {
-			flags = IsOutput;
-		} else if (strings_equal_ignore_case (prop->value(), "input") || strings_equal_ignore_case (prop->value(), "in")) {
-			flags = IsInput;
+	while (1) {
+		output_fifo.get_write_vector (&vec);
+		if (vec.len[0] + vec.len[1] >= output_fifo.bufsize() - 1) {
+			break;
 		}
-
-		have_mode = true;
+		usleep (check_interval_usecs);
 	}
-
-	if (!have_tag || !have_mode) {
-		throw failed_constructor();
-	}
-}
-
-void
-Port::jack_halted ()
-{
-	_jack_client = 0;
-	_jack_port = 0;
 }
 
 int
@@ -305,6 +250,8 @@ Port::write(byte * msg, size_t msglen, timestamp_t timestamp)
 		
 		ret = msglen;
 
+		usleep (5000);
+
 	} else {
 
 		// XXX This had to be temporarily commented out to make export work again
@@ -359,7 +306,7 @@ Port::flush (void* jack_port_buffer)
 	output_fifo.get_read_vector (&vec);
 
 	if (vec.len[0] + vec.len[1]) {
-		// cerr << "Flush " << vec.len[0] + vec.len[1] << " events from non-process FIFO\n";
+		cerr << "Flush " << vec.len[0] + vec.len[1] << " events from non-process FIFO\n";
 	}
 
 	if (vec.len[0]) {
@@ -417,14 +364,7 @@ Port::create_port ()
 XMLNode& 
 Port::get_state () const
 {
-	XMLNode* root = new XMLNode (state_node_name);
-	root->add_property ("tag", _tagname);
-
-	if (_flags == IsInput) {
-		root->add_property ("mode", "input");
-	} else {
-		root->add_property ("mode", "output");
-	}
+	XMLNode& root = PortBase::get_state ();
 	
 #if 0
 	byte device_inquiry[6];
@@ -454,15 +394,15 @@ Port::get_state () const
 		}
 		
 		if (!connection_string.empty()) {
-			root->add_property ("connections", connection_string);
+			root.add_property ("connections", connection_string);
 		}
 	} else {
 		if (!_connections.empty()) {
-			root->add_property ("connections", _connections);
+			root.add_property ("connections", _connections);
 		}
 	}
 
-	return *root;
+	return root;
 }
 
 void
@@ -470,9 +410,7 @@ Port::set_state (const XMLNode& node)
 {
 	const XMLProperty* prop;
 
-	if ((prop = node.property ("tag")) == 0 || prop->value() != _tagname) {
-		return;
-	}
+	PortBase::set_state (node);
 
 	if ((prop = node.property ("connections")) != 0 && _jack_port) {
 		_connections = prop->value ();
diff --git a/libs/midi++2/port_base.cc b/libs/midi++2/port_base.cc
new file mode 100644
index 0000000000..830dc4efe6
--- /dev/null
+++ b/libs/midi++2/port_base.cc
@@ -0,0 +1,186 @@
+/*
+    Copyright (C) 1998 Paul Barton-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.
+
+    $Id: port.cc 11871 2012-04-10 16:27:01Z paul $
+*/
+#include <iostream>
+#include <cstdio>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <jack/jack.h>
+#include <jack/midiport.h>
+
+#include "pbd/xml++.h"
+#include "pbd/error.h"
+#include "pbd/failed_constructor.h"
+#include "pbd/convert.h"
+#include "pbd/strsplit.h"
+#include "pbd/stacktrace.h"
+
+#include "midi++/types.h"
+#include "midi++/port_base.h"
+#include "midi++/channel.h"
+
+using namespace MIDI;
+using namespace std;
+using namespace PBD;
+
+string PortBase::state_node_name = "MIDI-port";
+
+PortBase::PortBase (string const & name, Flags flags)
+	: _flags (flags)
+	, _centrally_parsed (true)
+{
+	init (name, flags);
+}
+
+PortBase::PortBase (const XMLNode& node)
+	: _centrally_parsed (true)
+{
+	
+	Descriptor desc (node);
+
+	init (desc.tag, desc.flags);
+
+	set_state (node);
+}
+
+void
+PortBase::init (string const & name, Flags flags)
+{
+	_ok = false;  /* derived class must set to true if constructor
+			 succeeds.
+		      */
+
+	_parser = 0;
+
+	_tagname = name;
+	_flags = flags;
+
+	_parser = new Parser (*this);
+
+	for (int i = 0; i < 16; i++) {
+		_channel[i] = new Channel (i, *this);
+		_channel[i]->connect_signals ();
+	}
+}
+
+PortBase::~PortBase ()
+{
+	for (int i = 0; i < 16; i++) {
+		delete _channel[i];
+	}
+}
+
+/** Send a clock tick message.
+ * \return true on success.
+ */
+bool
+PortBase::clock (timestamp_t timestamp)
+{
+	static byte clockmsg = 0xf8;
+	
+	if (sends_output()) {
+		return midimsg (&clockmsg, 1, timestamp);
+	}
+	
+	return false;
+}
+
+std::ostream & MIDI::operator << ( std::ostream & os, const MIDI::PortBase & port )
+{
+	using namespace std;
+	os << "MIDI::Port { ";
+	os << "name: " << port.name();
+	os << "; ";
+	os << "ok: " << port.ok();
+	os << "; ";
+	os << " }";
+	return os;
+}
+
+PortBase::Descriptor::Descriptor (const XMLNode& node)
+{
+	const XMLProperty *prop;
+	bool have_tag = false;
+	bool have_mode = false;
+
+	if ((prop = node.property ("tag")) != 0) {
+		tag = prop->value();
+		have_tag = true;
+	}
+
+	if ((prop = node.property ("mode")) != 0) {
+
+		if (strings_equal_ignore_case (prop->value(), "output") || strings_equal_ignore_case (prop->value(), "out")) {
+			flags = IsOutput;
+		} else if (strings_equal_ignore_case (prop->value(), "input") || strings_equal_ignore_case (prop->value(), "in")) {
+			flags = IsInput;
+		}
+
+		have_mode = true;
+	}
+
+	if (!have_tag || !have_mode) {
+		throw failed_constructor();
+	}
+}
+
+XMLNode& 
+PortBase::get_state () const
+{
+	XMLNode* root = new XMLNode (state_node_name);
+	root->add_property ("tag", _tagname);
+
+	if (_flags == IsInput) {
+		root->add_property ("mode", "input");
+	} else {
+		root->add_property ("mode", "output");
+	}
+	
+#if 0
+	byte device_inquiry[6];
+
+	device_inquiry[0] = 0xf0;
+	device_inquiry[0] = 0x7e;
+	device_inquiry[0] = 0x7f;
+	device_inquiry[0] = 0x06;
+	device_inquiry[0] = 0x02;
+	device_inquiry[0] = 0xf7;
+	
+	write (device_inquiry, sizeof (device_inquiry), 0);
+#endif
+
+	return *root;
+}
+
+void
+PortBase::set_state (const XMLNode& node)
+{
+	const XMLProperty* prop;
+
+	if ((prop = node.property ("tag")) == 0 || prop->value() != _tagname) {
+		return;
+	}
+}
+
+bool
+PortBase::centrally_parsed() const
+{
+	return _centrally_parsed;
+}
diff --git a/libs/midi++2/wscript b/libs/midi++2/wscript
index b810bdc802..eccefe695d 100644
--- a/libs/midi++2/wscript
+++ b/libs/midi++2/wscript
@@ -49,6 +49,7 @@ def build(bld):
             channel.cc
             manager.cc
             parser.cc
+            port_base.cc
             port.cc
             midnam_patch.cc
             mmc.cc