Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 3412 insertions, 0 deletions

diff --git a/third_party/rust/midir/src/backend/alsa/mod.rs b/third_party/rust/midir/src/backend/alsa/mod.rs
new file mode 100755
index 0000000000..f57ffb798e
--- /dev/null
+++ b/third_party/rust/midir/src/backend/alsa/mod.rs
@@ -0,0 +1,733 @@
+extern crate libc;
+extern crate alsa;
+
+use std::mem;
+use std::thread::{Builder, JoinHandle};
+use std::io::{stderr, Write};
+use std::ffi::{CString, CStr};
+
+use self::alsa::{Seq, Direction};
+use self::alsa::seq::{PortInfo, PortSubscribe, Addr, QueueTempo, EventType, PortCap, PortType};
+
+use ::{MidiMessage, Ignore};
+use ::errors::*;
+
+mod helpers {
+    use super::alsa::seq::{Seq, Addr, ClientIter, PortIter, PortInfo, PortCap, MidiEvent, PortType};
+    use ::errors::PortInfoError;
+
+    pub fn poll(fds: &mut [super::libc::pollfd], timeout: i32) -> i32 {
+        unsafe { super::libc::poll(fds.as_mut_ptr(), fds.len() as super::libc::nfds_t, timeout) }
+    }
+
+    #[inline]
+    pub fn get_ports<F, T>(s: &Seq, capability: PortCap, f: F) -> Vec<T> where F: Fn(PortInfo) -> T {
+        ClientIter::new(s).flat_map(|c| PortIter::new(s, c.get_client()))
+                          .filter(|p| p.get_type().intersects(PortType::MIDI_GENERIC | PortType::SYNTH | PortType::APPLICATION))
+                          .filter(|p| p.get_capability().intersects(capability))
+                          .map(f)
+                          .collect()
+    }
+
+    #[inline]
+    pub fn get_port_count(s: &Seq, capability: PortCap) -> usize {
+        ClientIter::new(s).flat_map(|c| PortIter::new(s, c.get_client()))
+                          .filter(|p| p.get_type().intersects(PortType::MIDI_GENERIC | PortType::SYNTH | PortType::APPLICATION))
+                          .filter(|p| p.get_capability().intersects(capability))
+                          .count()
+    }
+
+    #[inline]
+    pub fn get_port_name(s: &Seq, addr: Addr) -> Result<String, PortInfoError> {
+        use std::fmt::Write;
+
+        let pinfo = match s.get_any_port_info(addr) {
+            Ok(p) => p,
+            Err(_) => return Err(PortInfoError::InvalidPort)
+        };
+
+        let cinfo = s.get_any_client_info(pinfo.get_client()).map_err(|_| PortInfoError::CannotRetrievePortName)?;
+        let mut output = String::new();
+        write!(&mut output, "{}:{} {}:{}", 
+            cinfo.get_name().map_err(|_| PortInfoError::CannotRetrievePortName)?,
+            pinfo.get_name().map_err(|_| PortInfoError::CannotRetrievePortName)?,
+            pinfo.get_client(), // These lines added to make sure devices are listed
+            pinfo.get_port()    // with full portnames added to ensure individual device names
+        ).unwrap();
+        Ok(output)
+    }
+
+    pub struct EventDecoder {
+        ev: MidiEvent
+    }
+
+    impl EventDecoder {
+        pub fn new(merge_commands: bool) -> EventDecoder {
+            let coder = MidiEvent::new(0).unwrap();
+            coder.enable_running_status(merge_commands);
+            EventDecoder { ev: coder }
+        }
+
+        #[inline]
+        pub fn get_wrapped(&mut self) -> &mut MidiEvent {
+            &mut self.ev
+        }
+    }
+
+    pub struct EventEncoder {
+        ev: MidiEvent,
+        buffer_size: u32
+    }
+
+    unsafe impl Send for EventEncoder {}
+
+    impl EventEncoder {
+        #[inline]
+        pub fn new(buffer_size: u32) -> EventEncoder {
+            EventEncoder {
+                ev: MidiEvent::new(buffer_size).unwrap(),
+                buffer_size: buffer_size
+            }
+        }
+
+        #[inline]
+        pub fn get_buffer_size(&self) -> u32 {
+            self.buffer_size
+        }
+
+        #[inline]
+        pub fn resize_buffer(&mut self, bufsize: u32) -> Result<(), ()> {
+            match self.ev.resize_buffer(bufsize) {
+                Ok(_) => {
+                    self.buffer_size = bufsize;
+                    Ok(())
+                },
+                Err(_) => Err(())
+            }
+        }
+
+        #[inline]
+        pub fn get_wrapped(&mut self) -> &mut MidiEvent {
+            &mut self.ev
+        }
+    }
+}
+
+const INITIAL_CODER_BUFFER_SIZE: usize = 32;
+
+pub struct MidiInput {
+    ignore_flags: Ignore,
+    seq: Option<Seq>,
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiInputPort {
+    addr: Addr
+}
+
+pub struct MidiInputConnection<T: 'static> {
+    subscription: Option<PortSubscribe>,
+    thread: Option<JoinHandle<(HandlerData<T>, T)>>,
+    vport: i32, // TODO: probably port numbers are only u8, therefore could use Option<u8>
+    trigger_send_fd: i32,
+}
+
+struct HandlerData<T: 'static> {
+    ignore_flags: Ignore,
+    seq: Seq,
+    trigger_rcv_fd: i32,
+    callback: Box<dyn FnMut(u64, &[u8], &mut T) + Send>,
+    queue_id: i32, // an input queue is needed to get timestamped events
+}
+
+impl MidiInput {
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        let seq = match Seq::open(None, None, true) {
+            Ok(s) => s,
+            Err(_) => { return Err(InitError); }
+        };
+        
+        let c_client_name = CString::new(client_name).map_err(|_| InitError)?;
+        seq.set_client_name(&c_client_name).map_err(|_| InitError)?;
+        
+        Ok(MidiInput {
+            ignore_flags: Ignore::None,
+            seq: Some(seq),
+        })
+    }
+    
+    pub fn ignore(&mut self, flags: Ignore) {
+        self.ignore_flags = flags;
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiInputPort> {
+        helpers::get_ports(self.seq.as_ref().unwrap(), PortCap::READ | PortCap::SUBS_READ, |p| ::common::MidiInputPort {
+            imp: MidiInputPort {
+                addr: p.addr()
+            }
+        })
+    }
+    
+    pub fn port_count(&self) -> usize {
+        helpers::get_port_count(self.seq.as_ref().unwrap(), PortCap::READ | PortCap::SUBS_READ)
+    }
+    
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        helpers::get_port_name(self.seq.as_ref().unwrap(), port.addr)
+    }
+    
+    fn init_queue(&mut self) -> i32 {
+        let seq = self.seq.as_mut().unwrap();
+        let mut queue_id = 0;
+        // Create the input queue
+        if !cfg!(feature = "avoid_timestamping") {
+            queue_id = seq.alloc_named_queue(unsafe { CStr::from_bytes_with_nul_unchecked(b"midir queue\0") }).unwrap();
+            // Set arbitrary tempo (mm=100) and resolution (240)
+            let qtempo = QueueTempo::empty().unwrap();
+            qtempo.set_tempo(600_000);
+            qtempo.set_ppq(240);
+            seq.set_queue_tempo(queue_id, &qtempo).unwrap();
+            let _ = seq.drain_output();
+        }
+        
+        queue_id
+    }
+    
+    fn init_trigger(&mut self) -> Result<[i32; 2], ()> {
+        let mut trigger_fds = [-1, -1];
+        
+        if unsafe { self::libc::pipe(trigger_fds.as_mut_ptr()) } == -1 {
+            Err(())
+        } else {
+            Ok(trigger_fds)
+        }
+    }
+    
+    fn create_port(&mut self, port_name: &CStr, queue_id: i32) -> Result<i32, ()> {
+        let mut pinfo = PortInfo::empty().unwrap();
+        // these functions are private, and the values are zeroed already by `empty()`
+        //pinfo.set_client(0);
+        //pinfo.set_port(0);
+        pinfo.set_capability(PortCap::WRITE | PortCap::SUBS_WRITE);
+        pinfo.set_type(PortType::MIDI_GENERIC | PortType::APPLICATION);
+        pinfo.set_midi_channels(16);
+        
+        if !cfg!(feature = "avoid_timestamping") {
+            pinfo.set_timestamping(true);
+            pinfo.set_timestamp_real(true);
+            pinfo.set_timestamp_queue(queue_id);
+        }
+        
+        pinfo.set_name(port_name);
+        match self.seq.as_mut().unwrap().create_port(&mut pinfo) {
+            Ok(_) => Ok(pinfo.get_port()),
+            Err(_) => Err(())
+        }
+    }
+    
+    fn start_input_queue(&mut self, queue_id: i32) {
+        if !cfg!(feature = "avoid_timestamping") {
+            let seq = self.seq.as_mut().unwrap();
+            let _ = seq.control_queue(queue_id, EventType::Start, 0, None);
+            let _ = seq.drain_output();
+        }
+    }
+    
+    pub fn connect<F, T: Send>(
+        mut self, port: &MidiInputPort, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<Self>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        
+        let trigger_fds = match self.init_trigger() {
+            Ok(fds) => fds,
+            Err(()) => { return Err(ConnectError::other("could not create communication pipe for ALSA handler", self)); }
+        };
+        
+        let queue_id = self.init_queue();
+
+        let src_pinfo = match self.seq.as_ref().unwrap().get_any_port_info(port.addr) {
+            Ok(p) => p,
+            Err(_) => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+        };
+
+        let c_port_name = match CString::new(port_name) {
+            Ok(c_port_name) => c_port_name,
+            Err(_) => return Err(ConnectError::other("port_name must not contain null bytes", self))
+        };
+        
+        let vport = match self.create_port(&c_port_name, queue_id) {
+            Ok(vp) => vp,
+            Err(_) => {
+                return Err(ConnectError::other("could not create ALSA input port", self));
+            }
+        };
+        
+        // Make subscription
+        let sub = PortSubscribe::empty().unwrap();
+        sub.set_sender(src_pinfo.addr());
+        sub.set_dest(Addr { client: self.seq.as_ref().unwrap().client_id().unwrap(), port: vport});
+        if self.seq.as_ref().unwrap().subscribe_port(&sub).is_err() {
+            return Err(ConnectError::other("could not create ALSA input subscription", self));
+        }
+        let subscription = sub;
+        
+        // Start the input queue
+        self.start_input_queue(queue_id);
+
+        // Start our MIDI input thread.
+        let handler_data = HandlerData {
+            ignore_flags: self.ignore_flags,
+            seq: self.seq.take().unwrap(),
+            trigger_rcv_fd: trigger_fds[0],
+            callback: Box::new(callback),
+            queue_id: queue_id
+        };
+        
+        let threadbuilder = Builder::new();
+        let name = format!("midir ALSA input handler (port '{}')", port_name);
+        let threadbuilder = threadbuilder.name(name);
+        let thread = match threadbuilder.spawn(move || {
+            let mut d = data;
+            let h = handle_input(handler_data, &mut d);
+            (h, d) // return both the handler data and the user data 
+        }) {
+            Ok(handle) => handle,
+            Err(_) => {
+                //unsafe { snd_seq_unsubscribe_port(self.seq.as_mut_ptr(), sub.as_ptr()) };
+                return Err(ConnectError::other("could not start ALSA input handler thread", self));
+            }
+        };
+
+        Ok(MidiInputConnection {
+            subscription: Some(subscription),
+            thread: Some(thread),
+            vport: vport,
+            trigger_send_fd: trigger_fds[1]
+        })
+    }
+    
+    pub fn create_virtual<F, T: Send>(
+        mut self, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<Self>>
+    where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        let trigger_fds = match self.init_trigger() {
+            Ok(fds) => fds,
+            Err(()) => { return Err(ConnectError::other("could not create communication pipe for ALSA handler", self)); }
+        };
+        
+        let queue_id = self.init_queue();
+
+        let c_port_name = match CString::new(port_name) {
+            Ok(c_port_name) => c_port_name,
+            Err(_) => return Err(ConnectError::other("port_name must not contain null bytes", self))
+        };
+        
+        let vport = match self.create_port(&c_port_name, queue_id) {
+            Ok(vp) => vp,
+            Err(_) => {
+                return Err(ConnectError::other("could not create ALSA input port", self));
+            }
+        };
+        
+        // Start the input queue
+        self.start_input_queue(queue_id);
+        
+        // Start our MIDI input thread.
+        let handler_data = HandlerData {
+            ignore_flags: self.ignore_flags,
+            seq: self.seq.take().unwrap(),
+            trigger_rcv_fd: trigger_fds[0],
+            callback: Box::new(callback),
+            queue_id: queue_id
+        };
+        
+        let threadbuilder = Builder::new();
+        let thread = match threadbuilder.spawn(move || {
+            let mut d = data;
+            let h = handle_input(handler_data, &mut d);
+            (h, d) // return both the handler data and the user data 
+        }) {
+            Ok(handle) => handle,
+            Err(_) => {
+                //unsafe { snd_seq_unsubscribe_port(self.seq.as_mut_ptr(), sub.as_ptr()) };
+                return Err(ConnectError::other("could not start ALSA input handler thread", self));
+            }
+        };
+
+        Ok(MidiInputConnection {
+            subscription: None,
+            thread: Some(thread),
+            vport: vport,
+            trigger_send_fd: trigger_fds[1]
+        })
+    }
+}
+
+impl<T> MidiInputConnection<T> {
+    pub fn close(mut self) -> (MidiInput, T) {
+        let (handler_data, user_data) = self.close_internal();
+        
+        (MidiInput {
+            ignore_flags: handler_data.ignore_flags,
+            seq: Some(handler_data.seq),
+        }, user_data)
+    }
+    
+    /// This must only be called if the handler thread has not yet been shut down
+    fn close_internal(&mut self) -> (HandlerData<T>, T) {
+        // Request the thread to stop.
+        let _res = unsafe { self::libc::write(self.trigger_send_fd, &false as *const bool as *const _, mem::size_of::<bool>() as self::libc::size_t) };
+        
+        let thread = self.thread.take().unwrap(); 
+        // Join the thread to get the handler_data back
+        let (handler_data, user_data) = match thread.join() {
+            Ok(data) => data,
+            // TODO: handle this more gracefully?
+            Err(e) => {
+                if let Some(e) = e.downcast_ref::<&'static str>() {
+                    panic!("Error when joining ALSA thread: {}", e);
+                } else {
+                    panic!("Unknown error when joining ALSA thread: {:?}", e);
+                }
+            }
+        };
+        
+        // TODO: find out why snd_seq_unsubscribe_port takes a long time if there was not yet any input message
+        if let Some(ref subscription) = self.subscription {
+            let _ = handler_data.seq.unsubscribe_port(subscription.get_sender(), subscription.get_dest());
+        }
+        
+        // Close the trigger fds (TODO: make sure that these are closed even in the presence of panic in thread)
+        unsafe {
+            self::libc::close(handler_data.trigger_rcv_fd);
+            self::libc::close(self.trigger_send_fd);
+        }
+        
+        // Stop and free the input queue
+        if !cfg!(feature = "avoid_timestamping") {
+            let _ = handler_data.seq.control_queue(handler_data.queue_id, EventType::Stop, 0, None);
+            let _ = handler_data.seq.drain_output();
+            let _ = handler_data.seq.free_queue(handler_data.queue_id);
+        }
+        
+        // Delete the port
+        let _ = handler_data.seq.delete_port(self.vport);
+        
+        (handler_data, user_data)
+    }
+}
+
+
+impl<T> Drop for MidiInputConnection<T> {
+    fn drop(&mut self) {
+        // Use `self.thread` as a flag whether the connection has already been dropped
+        if self.thread.is_some() {
+            self.close_internal();
+        }
+    }
+}
+
+pub struct MidiOutput {
+    seq: Option<Seq>, // TODO: if `Seq` is marked as non-zero, this should just be pointer-sized 
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiOutputPort {
+    addr: Addr
+}
+
+pub struct MidiOutputConnection {
+    seq: Option<Seq>,
+    vport: i32,
+    coder: helpers::EventEncoder,
+    subscription: Option<PortSubscribe>
+}
+
+impl MidiOutput {
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        let seq = match Seq::open(None, Some(Direction::Playback), true) {
+            Ok(s) => s,
+            Err(_) => { return Err(InitError); }
+        };
+        
+        let c_client_name = CString::new(client_name).map_err(|_| InitError)?;
+        seq.set_client_name(&c_client_name).map_err(|_| InitError)?;
+        
+        Ok(MidiOutput {
+            seq: Some(seq),
+        })
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiOutputPort> {
+        helpers::get_ports(self.seq.as_ref().unwrap(), PortCap::WRITE | PortCap::SUBS_WRITE, |p| ::common::MidiOutputPort {
+            imp: MidiOutputPort {
+                addr: p.addr()
+            }
+        })
+    }
+    
+    pub fn port_count(&self) -> usize {
+        helpers::get_port_count(self.seq.as_ref().unwrap(), PortCap::WRITE | PortCap::SUBS_WRITE)
+    }
+    
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        helpers::get_port_name(self.seq.as_ref().unwrap(), port.addr)
+    }
+    
+    pub fn connect(mut self, port: &MidiOutputPort, port_name: &str) -> Result<MidiOutputConnection, ConnectError<Self>> {
+        let pinfo = match self.seq.as_ref().unwrap().get_any_port_info(port.addr) {
+            Ok(p) => p,
+            Err(_) => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+        };
+
+        let c_port_name = match CString::new(port_name) {
+            Ok(c_port_name) => c_port_name,
+            Err(_) => return Err(ConnectError::other("port_name must not contain null bytes", self))
+        };
+
+        let vport = match self.seq.as_ref().unwrap().create_simple_port(&c_port_name, PortCap::READ | PortCap::SUBS_READ, PortType::MIDI_GENERIC | PortType::APPLICATION) {
+            Ok(vport) => vport,
+            Err(_) => return Err(ConnectError::other("could not create ALSA output port", self))
+        };
+
+        // Make subscription
+        let sub = PortSubscribe::empty().unwrap();
+        sub.set_sender(Addr { client: self.seq.as_ref().unwrap().client_id().unwrap(), port: vport });
+        sub.set_dest(pinfo.addr());
+        sub.set_time_update(true);
+        sub.set_time_real(true);
+        if self.seq.as_ref().unwrap().subscribe_port(&sub).is_err() {
+            return Err(ConnectError::other("could not create ALSA output subscription", self));
+        }
+        
+        Ok(MidiOutputConnection {
+            seq: self.seq.take(),
+            vport: vport,
+            coder: helpers::EventEncoder::new(INITIAL_CODER_BUFFER_SIZE as u32),
+            subscription: Some(sub)
+        })
+    }
+    
+    pub fn create_virtual(
+        mut self, port_name: &str
+    ) -> Result<MidiOutputConnection, ConnectError<Self>> {
+        let c_port_name = match CString::new(port_name) {
+            Ok(c_port_name) => c_port_name,
+            Err(_) => return Err(ConnectError::other("port_name must not contain null bytes", self))
+        };
+
+        let vport = match self.seq.as_ref().unwrap().create_simple_port(&c_port_name, PortCap::READ | PortCap::SUBS_READ, PortType::MIDI_GENERIC | PortType::APPLICATION) {
+            Ok(vport) => vport,
+            Err(_) => return Err(ConnectError::other("could not create ALSA output port", self))
+        };
+        
+        Ok(MidiOutputConnection {
+            seq: self.seq.take(),
+            vport: vport,
+            coder: helpers::EventEncoder::new(INITIAL_CODER_BUFFER_SIZE as u32),
+            subscription: None
+        })
+    }
+}
+        
+
+impl MidiOutputConnection {
+    pub fn close(mut self) -> MidiOutput {
+        self.close_internal();
+        
+        MidiOutput {
+            seq: self.seq.take(),
+        }
+    }
+    
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {  
+        let nbytes = message.len();
+        assert!(nbytes <= u32::max_value() as usize);
+        
+        if nbytes > self.coder.get_buffer_size() as usize {
+            if self.coder.resize_buffer(nbytes as u32).is_err() {
+                return Err(SendError::Other("could not resize ALSA encoding buffer"));
+            }
+        }
+        
+        let mut ev = match self.coder.get_wrapped().encode(message) {
+            Ok((_, Some(ev))) => ev,
+            _ => return Err(SendError::InvalidData("ALSA encoder reported invalid data"))
+        };
+
+        ev.set_source(self.vport);
+        ev.set_subs();
+        ev.set_direct();
+        
+        // Send the event.
+        if self.seq.as_ref().unwrap().event_output(&mut ev).is_err() {
+            return Err(SendError::Other("could not send encoded ALSA message"));
+        }
+        
+        let _ = self.seq.as_mut().unwrap().drain_output();
+        Ok(())
+    }
+    
+    fn close_internal(&mut self) {
+        let seq = self.seq.as_mut().unwrap();
+        if let Some(ref subscription) = self.subscription {
+            let _ = seq.unsubscribe_port(subscription.get_sender(), subscription.get_dest());
+        }
+        let _ = seq.delete_port(self.vport);
+    }
+}
+
+impl Drop for MidiOutputConnection {
+    fn drop(&mut self) {
+        if self.seq.is_some() {
+            self.close_internal();
+        }
+    }
+}
+
+fn handle_input<T>(mut data: HandlerData<T>, user_data: &mut T) -> HandlerData<T> {
+    use self::alsa::PollDescriptors;
+    use self::alsa::seq::Connect;
+
+    let mut continue_sysex: bool = false;
+    
+    // ALSA documentation says:
+    // The required buffer size for a sequencer event it as most 12 bytes, except for System Exclusive events (which we handle separately)
+    let mut buffer = [0; 12];
+    
+    let mut coder = helpers::EventDecoder::new(false);
+    
+    let mut poll_fds: Box<[self::libc::pollfd]>;
+    {
+        let poll_desc_info = (&data.seq, Some(Direction::Capture));
+        let poll_fd_count = poll_desc_info.count() + 1;
+        let mut vec = Vec::with_capacity(poll_fd_count);
+        unsafe {    
+            vec.set_len(poll_fd_count);
+            poll_fds = vec.into_boxed_slice();
+        }
+        poll_desc_info.fill(&mut poll_fds[1..]).unwrap();
+    }
+    poll_fds[0].fd = data.trigger_rcv_fd;
+    poll_fds[0].events = self::libc::POLLIN;
+
+            
+    let mut message = MidiMessage::new();
+
+    { // open scope where we can borrow data.seq
+    let mut seq_input = data.seq.input();
+    
+    let mut do_input = true;
+    while do_input {
+        if let Ok(0) = seq_input.event_input_pending(true) {
+            // No data pending
+            if helpers::poll(&mut poll_fds, -1) >= 0 {
+                // Read from our "channel" whether we should stop the thread 
+                if poll_fds[0].revents & self::libc::POLLIN != 0 {
+                    let _res = unsafe { self::libc::read(poll_fds[0].fd, mem::transmute(&mut do_input), mem::size_of::<bool>() as self::libc::size_t) };
+                }
+            }
+            continue;
+        }
+
+        // This is a bit weird, but we now have to decode an ALSA MIDI
+        // event (back) into MIDI bytes. We'll ignore non-MIDI types.
+
+        // The ALSA sequencer has a maximum buffer size for MIDI sysex
+        // events of 256 bytes. If a device sends sysex messages larger
+        // than this, they are segmented into 256 byte chunks.    So,
+        // we'll watch for this and concatenate sysex chunks into a
+        // single sysex message if necessary.
+        //
+        // TODO: Figure out if this is still true (seems to not be the case)
+        //       If not (i.e., each event represents a complete message), we can
+        //       call the user callback with the byte buffer directly, without the
+        //       copying to `message.bytes` first.
+        if !continue_sysex { message.bytes.clear() }
+
+        let ignore_flags = data.ignore_flags;
+
+        // If here, there should be data.
+        let mut ev = match seq_input.event_input() {
+            Ok(ev) => ev,
+            Err(ref e) if e.errno() == alsa::nix::errno::Errno::ENOSPC => {
+                let _ = writeln!(stderr(), "\nError in handle_input: ALSA MIDI input buffer overrun!\n");
+                continue;
+            },
+            Err(ref e) if e.errno() == alsa::nix::errno::Errno::EAGAIN => {
+                let _ = writeln!(stderr(), "\nError in handle_input: no input event from ALSA MIDI input buffer!\n");
+                continue;
+            },
+            Err(ref e) => {
+                let _ = writeln!(stderr(), "\nError in handle_input: unknown ALSA MIDI input error ({})!\n", e);
+                //perror("System reports");
+                continue;
+            }
+        };
+        
+        let do_decode = match ev.get_type() {
+            EventType::PortSubscribed => {
+                if cfg!(debug) { println!("Notice from handle_input: ALSA port connection made!") };
+                false
+            },
+            EventType::PortUnsubscribed => {
+                if cfg!(debug) {
+                    let _ = writeln!(stderr(), "Notice from handle_input: ALSA port connection has closed!");
+                    let connect = ev.get_data::<Connect>().unwrap();
+                    let _ = writeln!(stderr(), "sender = {}:{}, dest = {}:{}",
+                        connect.sender.client,
+                        connect.sender.port,
+                        connect.dest.client,
+                        connect.dest.port
+                    );
+                }
+                false
+            },
+            EventType::Qframe => { // MIDI time code
+                !ignore_flags.contains(Ignore::Time)
+            },
+            EventType::Tick => { // 0xF9 ... MIDI timing tick
+                !ignore_flags.contains(Ignore::Time)
+            },
+            EventType::Clock => { // 0xF8 ... MIDI timing (clock) tick
+                !ignore_flags.contains(Ignore::Time)
+            },
+            EventType::Sensing => { // Active sensing
+                !ignore_flags.contains(Ignore::ActiveSense)
+            },
+            EventType::Sysex => {
+                if !ignore_flags.contains(Ignore::Sysex) {
+                    // Directly copy the data from the external buffer to our message
+                    message.bytes.extend_from_slice(ev.get_ext().unwrap());
+                    continue_sysex = *message.bytes.last().unwrap() != 0xF7;
+                }
+                false // don't ever decode sysex messages (it would unnecessarily copy the message content to another buffer)
+            },
+            _ => true
+        };
+
+        // NOTE: SysEx messages have already been "decoded" at this point!
+        if do_decode {
+            if let Ok(nbytes) = coder.get_wrapped().decode(&mut buffer, &mut ev) {
+                if nbytes > 0 {
+                    message.bytes.extend_from_slice(&buffer[0..nbytes]);
+                }
+            }
+        }
+
+        if message.bytes.len() == 0 || continue_sysex { continue; }
+
+        // Calculate the time stamp:
+        // Use the ALSA sequencer event time data.
+        // (thanks to Pedro Lopez-Cabanillas!).
+        let alsa_time = ev.get_time().unwrap();
+        let secs = alsa_time.as_secs();
+        let nsecs = alsa_time.subsec_nanos();
+
+        message.timestamp = ( secs as u64 * 1_000_000 ) + ( nsecs as u64 / 1_000 );        
+        (data.callback)(message.timestamp, &message.bytes, user_data);
+    }
+    
+    } // close scope where data.seq is borrowed
+    data // return data back to thread owner
+}
diff --git a/third_party/rust/midir/src/backend/coremidi/mod.rs b/third_party/rust/midir/src/backend/coremidi/mod.rs
new file mode 100644
index 0000000000..31fd905778
--- /dev/null
+++ b/third_party/rust/midir/src/backend/coremidi/mod.rs
@@ -0,0 +1,351 @@
+extern crate coremidi;
+
+use std::sync::{Arc, Mutex};
+
+use ::errors::*;
+use ::Ignore;
+use ::MidiMessage;
+
+use self::coremidi::*;
+
+mod external {
+    #[link(name = "CoreAudio", kind = "framework")]
+    extern "C" {
+        pub fn AudioConvertHostTimeToNanos(inHostTime: u64) -> u64;
+        pub fn AudioGetCurrentHostTime() -> u64;
+    }
+}
+
+pub struct MidiInput {
+    client: Client,
+    ignore_flags: Ignore
+}
+
+#[derive(Clone)]
+pub struct MidiInputPort {
+    source: Arc<Source>
+}
+
+impl PartialEq for MidiInputPort {
+    fn eq(&self, other: &Self) -> bool {
+        if let (Some(id1), Some(id2)) = (self.source.unique_id(), other.source.unique_id()) {
+            id1 == id2
+        } else {
+            // Acording to macos docs "The system assigns unique IDs to all objects.", so I think we can ignore this case
+            false
+        }
+    }
+}
+
+impl MidiInput {
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        match Client::new(client_name) {
+            Ok(cl) => Ok(MidiInput { client: cl, ignore_flags: Ignore::None }),
+            Err(_) => Err(InitError)
+        }
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiInputPort> {
+        Sources.into_iter().map(|s| ::common::MidiInputPort {
+            imp: MidiInputPort { source: Arc::new(s) }
+        }).collect()
+    }
+
+    pub fn ignore(&mut self, flags: Ignore) {
+        self.ignore_flags = flags;
+    }
+    
+    pub fn port_count(&self) -> usize {
+        Sources::count()
+    }
+    
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        match port.source.display_name() {
+            Some(name) => Ok(name),
+            None => Err(PortInfoError::CannotRetrievePortName)
+        }
+    }
+
+    fn handle_input<T>(packets: &PacketList, handler_data: &mut HandlerData<T>) {
+        let continue_sysex =  &mut handler_data.continue_sysex;
+        let ignore = handler_data.ignore_flags;
+        let message = &mut handler_data.message;
+        let data = &mut handler_data.user_data.as_mut().unwrap();
+        for p in packets.iter() {
+            let pdata = p.data();
+            if pdata.len() == 0 { continue; }
+
+            let mut timestamp = p.timestamp();
+            if timestamp == 0 { // this might happen for asnychronous sysex messages (?)
+                timestamp = unsafe { external::AudioGetCurrentHostTime() };
+            }
+
+            if !*continue_sysex {
+                message.timestamp = unsafe { external::AudioConvertHostTimeToNanos(timestamp) } as u64 / 1000;
+            }
+
+            let mut cur_byte = 0;
+            if *continue_sysex {
+                // We have a continuing, segmented sysex message.
+                if !ignore.contains(Ignore::Sysex) {
+                    // If we're not ignoring sysex messages, copy the entire packet.
+                    message.bytes.extend_from_slice(pdata);
+                }
+                *continue_sysex = pdata[pdata.len() - 1] != 0xF7;
+
+                if !ignore.contains(Ignore::Sysex) && !*continue_sysex {
+                    // If we reached the end of the sysex, invoke the user callback
+                    (handler_data.callback)(message.timestamp, &message.bytes, data);
+                    message.bytes.clear();
+                }
+            } else {
+                while cur_byte < pdata.len() {
+                    // We are expecting that the next byte in the packet is a status byte.
+                    let status = pdata[cur_byte];
+                    if status & 0x80 == 0 { break; }
+                    // Determine the number of bytes in the MIDI message.
+                    let size;
+                    if status < 0xC0 { size = 3; }
+                    else if status < 0xE0 { size = 2; }
+                    else if status < 0xF0 { size = 3; }
+                    else if status == 0xF0 {
+                        // A MIDI sysex
+                        if ignore.contains(Ignore::Sysex) {
+                            size = 0;
+                            cur_byte = pdata.len();
+                        } else {
+                            size = pdata.len() - cur_byte;
+                        }
+                        *continue_sysex = pdata[pdata.len() - 1] != 0xF7;
+                    }
+                    else if status == 0xF1 {
+                        // A MIDI time code message
+                        if ignore.contains(Ignore::Time) {
+                            size = 0;
+                            cur_byte += 2;
+                        } else {
+                            size = 2;
+                        }
+                    }
+                    else if status == 0xF2 { size = 3; }
+                    else if status == 0xF3 { size = 2; }
+                    else if status == 0xF8 && ignore.contains(Ignore::Time) {
+                        // A MIDI timing tick message and we're ignoring it.
+                        size = 0;
+                        cur_byte += 1;
+                    }
+                    else if status == 0xFE && ignore.contains(Ignore::ActiveSense) {
+                        // A MIDI active sensing message and we're ignoring it.
+                        size = 0;
+                        cur_byte += 1;
+                    }
+                    else { size = 1; }
+
+                    // Copy the MIDI data to our vector.
+                    if size > 0 {
+                        let message_bytes = &pdata[cur_byte..(cur_byte + size)];
+                        if !*continue_sysex {
+                            // This is either a non-sysex message or a non-segmented sysex message
+                            (handler_data.callback)(message.timestamp, message_bytes, data);
+                            message.bytes.clear();
+                        } else {
+                            // This is the beginning of a segmented sysex message
+                            message.bytes.extend_from_slice(message_bytes);
+                        }
+                        cur_byte += size;
+                    }
+                }
+            }
+        }
+    }
+    
+    pub fn connect<F, T: Send + 'static>(
+        self, port: &MidiInputPort, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        let handler_data = Arc::new(Mutex::new(HandlerData {
+            message: MidiMessage::new(),
+            ignore_flags: self.ignore_flags,
+            continue_sysex: false,
+            callback: Box::new(callback),
+            user_data: Some(data)
+        }));
+        let handler_data2 = handler_data.clone();
+        let iport = match self.client.input_port(port_name, move |packets| {
+            MidiInput::handle_input(packets, &mut *handler_data2.lock().unwrap())
+        }) {
+            Ok(p) => p,
+            Err(_) => return Err(ConnectError::other("error creating MIDI input port", self))
+        };
+        if let Err(_) = iport.connect_source(&port.source) {
+            return Err(ConnectError::other("error connecting MIDI input port", self));
+        }
+        Ok(MidiInputConnection {
+            client: self.client,
+            details: InputConnectionDetails::Explicit(iport),
+            handler_data: handler_data
+        })
+    }
+
+    pub fn create_virtual<F, T: Send + 'static>(
+        self, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+    where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+
+        let handler_data = Arc::new(Mutex::new(HandlerData {
+            message: MidiMessage::new(),
+            ignore_flags: self.ignore_flags,
+            continue_sysex: false,
+            callback: Box::new(callback),
+            user_data: Some(data)
+        }));
+        let handler_data2 = handler_data.clone();
+        let vrt = match self.client.virtual_destination(port_name, move |packets| {
+            MidiInput::handle_input(packets, &mut *handler_data2.lock().unwrap())
+        }) {
+            Ok(p) => p,
+            Err(_) => return Err(ConnectError::other("error creating MIDI input port", self))
+        };
+        Ok(MidiInputConnection {
+            client: self.client,
+            details: InputConnectionDetails::Virtual(vrt),
+            handler_data: handler_data
+        })
+    }
+}
+
+enum InputConnectionDetails {
+    Explicit(InputPort),
+    Virtual(VirtualDestination)
+}
+
+pub struct MidiInputConnection<T> {
+    client: Client,
+    #[allow(dead_code)]
+    details: InputConnectionDetails,
+    // TODO: get rid of Arc & Mutex?
+    //       synchronization is required because the borrow checker does not
+    //       know that the callback we're in here is never called concurrently
+    //       (always in sequence)
+    handler_data: Arc<Mutex<HandlerData<T>>>
+}
+
+impl<T> MidiInputConnection<T> {
+    pub fn close(self) -> (MidiInput, T) {
+        let mut handler_data_locked = self.handler_data.lock().unwrap();
+        (MidiInput {
+            client: self.client,
+            ignore_flags: handler_data_locked.ignore_flags
+        }, handler_data_locked.user_data.take().unwrap())
+    }
+}
+
+/// This is all the data that is stored on the heap as long as a connection
+/// is opened and passed to the callback handler.
+///
+/// It is important that `user_data` is the last field to not influence
+/// offsets after monomorphization.
+struct HandlerData<T> {
+    message: MidiMessage,
+    ignore_flags: Ignore,
+    continue_sysex: bool,
+    callback: Box<dyn FnMut(u64, &[u8], &mut T) + Send>,
+    user_data: Option<T>
+}
+
+pub struct MidiOutput {
+    client: Client
+}
+
+#[derive(Clone)]
+pub struct MidiOutputPort {
+    dest: Arc<Destination>
+}
+
+impl PartialEq for MidiOutputPort {
+    fn eq(&self, other: &Self) -> bool {
+        if let (Some(id1), Some(id2)) = (self.dest.unique_id(), other.dest.unique_id()) {
+            id1 == id2
+        } else {
+            // Acording to macos docs "The system assigns unique IDs to all objects.", so I think we can ignore this case
+            false
+        }
+    }
+}
+
+impl MidiOutput {
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        match Client::new(client_name) {
+            Ok(cl) => Ok(MidiOutput { client: cl }),
+            Err(_) => Err(InitError)
+        }
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiOutputPort> {
+        Destinations.into_iter().map(|d| ::common::MidiOutputPort {
+            imp: MidiOutputPort { dest: Arc::new(d) }
+        }).collect()
+    }
+    
+    pub fn port_count(&self) -> usize {
+        Destinations::count()
+    }
+    
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        match port.dest.display_name() {
+            Some(name) => Ok(name),
+            None => Err(PortInfoError::CannotRetrievePortName)
+        }
+    }
+    
+    pub fn connect(self, port: &MidiOutputPort, port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        let oport = match self.client.output_port(port_name) {
+            Ok(p) => p,
+            Err(_) => return Err(ConnectError::other("error creating MIDI output port", self))
+        };
+        Ok(MidiOutputConnection {
+            client: self.client,
+            details: OutputConnectionDetails::Explicit(oport, port.dest.clone())
+        })
+    }
+
+    pub fn create_virtual(self, port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        let vrt = match self.client.virtual_source(port_name) {
+            Ok(p) => p,
+            Err(_) => return Err(ConnectError::other("error creating virtual MIDI source", self))
+        };
+        Ok(MidiOutputConnection {
+            client: self.client,
+            details: OutputConnectionDetails::Virtual(vrt)
+        })
+    }
+}
+
+enum OutputConnectionDetails {
+    Explicit(OutputPort, Arc<Destination>),
+    Virtual(VirtualSource)
+}
+
+pub struct MidiOutputConnection {
+    client: Client,
+    details: OutputConnectionDetails
+}
+
+impl MidiOutputConnection {
+    pub fn close(self) -> MidiOutput {
+        MidiOutput { client: self.client }
+    }
+    
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {
+        let packets = PacketBuffer::new(0, message);
+        match self.details {
+            OutputConnectionDetails::Explicit(ref port, ref dest) => {
+                port.send(&dest, &packets).map_err(|_| SendError::Other("error sending MIDI message to port"))
+            },
+            OutputConnectionDetails::Virtual(ref vrt) => {
+                vrt.received(&packets).map_err(|_| SendError::Other("error sending MIDI to virtual destinations"))
+            }
+        }
+        
+    }
+}
diff --git a/third_party/rust/midir/src/backend/jack/mod.rs b/third_party/rust/midir/src/backend/jack/mod.rs
new file mode 100644
index 0000000000..92cc81a295
--- /dev/null
+++ b/third_party/rust/midir/src/backend/jack/mod.rs
@@ -0,0 +1,364 @@
+extern crate jack_sys;
+extern crate libc;
+
+use self::jack_sys::jack_nframes_t;
+use self::libc::c_void;
+
+use std::{mem, slice};
+use std::ffi::CString;
+
+mod wrappers;
+use self::wrappers::*;
+
+use ::{Ignore, MidiMessage};
+use ::errors::*;
+
+const OUTPUT_RINGBUFFER_SIZE: usize = 16384;
+
+struct InputHandlerData<T> {
+    port: Option<MidiPort>,
+    ignore_flags: Ignore,
+    callback: Box<dyn FnMut(u64, &[u8], &mut T) + Send>,
+    user_data: Option<T>
+}
+
+pub struct MidiInput {
+    ignore_flags: Ignore,
+    client: Option<Client>,
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiInputPort {
+    name: CString
+}
+
+pub struct MidiInputConnection<T> {
+    handler_data: Box<InputHandlerData<T>>,
+    client: Option<Client>
+}
+
+impl MidiInput {
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        let client = match Client::open(client_name, JackOpenOptions::NoStartServer) {
+            Ok(c) => c,
+            Err(_) => { return Err(InitError); } // TODO: maybe add message that Jack server might not be running
+        };
+        
+        Ok(MidiInput {
+            ignore_flags: Ignore::None,
+            client: Some(client),
+        })
+    }
+    
+    pub fn ignore(&mut self, flags: Ignore) {
+        self.ignore_flags = flags;
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiInputPort> {
+        let ports = self.client.as_ref().unwrap().get_midi_ports(PortFlags::PortIsOutput);
+        let mut result = Vec::with_capacity(ports.count());
+        for i in 0..ports.count() {
+            result.push(::common::MidiInputPort {
+                imp: MidiInputPort {
+                    name: ports.get_c_name(i).into()
+                }
+            })
+        }
+        result
+    }
+    
+    pub fn port_count(&self) -> usize {
+        self.client.as_ref().unwrap().get_midi_ports(PortFlags::PortIsOutput).count()
+    }
+    
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        Ok(port.name.to_string_lossy().into())
+    }
+    
+    fn activate_callback<F, T: Send>(&mut self, callback: F, data: T)
+            -> Box<InputHandlerData<T>>
+            where F: FnMut(u64, &[u8], &mut T) + Send + 'static
+    {
+        let handler_data = Box::new(InputHandlerData {
+            port: None,
+            ignore_flags: self.ignore_flags,
+            callback: Box::new(callback),
+            user_data: Some(data)
+        });
+        
+        let data_ptr = unsafe { mem::transmute_copy::<_, *mut InputHandlerData<T>>(&handler_data) };
+        
+        self.client.as_mut().unwrap().set_process_callback(handle_input::<T>, data_ptr as *mut c_void);
+        self.client.as_mut().unwrap().activate();
+        handler_data
+    }
+    
+    pub fn connect<F, T: Send>(
+        mut self, port: &MidiInputPort, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+
+        let mut handler_data = self.activate_callback(callback, data);
+        
+        // Create port ...
+        let dest_port = match self.client.as_mut().unwrap().register_midi_port(port_name, PortFlags::PortIsInput) {
+            Ok(p) => p,
+            Err(()) => { return Err(ConnectError::other("could not register JACK port", self)); }
+        };
+        
+        // ... and connect it to the output
+        if let Err(_) = self.client.as_mut().unwrap().connect(&port.name, dest_port.get_name()) {
+            return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self));
+        }
+        
+        handler_data.port = Some(dest_port);
+        
+        Ok(MidiInputConnection {
+            handler_data: handler_data,
+            client: self.client.take()
+        })
+    }
+    
+    pub fn create_virtual<F, T: Send>(
+        mut self, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<Self>>
+    where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+    
+        let mut handler_data = self.activate_callback(callback, data);
+        
+        // Create port
+        let port = match self.client.as_mut().unwrap().register_midi_port(port_name, PortFlags::PortIsInput) {
+            Ok(p) => p,
+            Err(()) => { return Err(ConnectError::other("could not register JACK port", self)); }
+        };
+        
+        handler_data.port = Some(port);
+        
+        Ok(MidiInputConnection {
+            handler_data: handler_data,
+            client: self.client.take()
+        })
+    }
+}
+
+impl<T> MidiInputConnection<T> {
+    pub fn close(mut self) -> (MidiInput, T) {
+        self.close_internal();
+        
+        (MidiInput {
+            client: self.client.take(),
+            ignore_flags: self.handler_data.ignore_flags,
+        }, self.handler_data.user_data.take().unwrap())
+    }
+    
+    fn close_internal(&mut self) {
+        let port = self.handler_data.port.take().unwrap();
+        self.client.as_mut().unwrap().unregister_midi_port(port);
+        self.client.as_mut().unwrap().deactivate();
+    }
+}
+
+impl<T> Drop for MidiInputConnection<T> {
+    fn drop(&mut self) {
+        if self.client.is_some() {
+            self.close_internal();
+        }
+    }
+}
+
+extern "C" fn handle_input<T>(nframes: jack_nframes_t, arg: *mut c_void) -> i32 {
+    let data: &mut InputHandlerData<T> = unsafe { &mut *(arg as *mut InputHandlerData<T>) };
+    
+    // Is port created?
+    if let Some(ref port) = data.port {
+        let buff = port.get_midi_buffer(nframes);
+        
+        let mut message = MidiMessage::new(); // TODO: create MidiMessage once and reuse its buffer for every handle_input call
+        
+        // We have midi events in buffer
+        let evcount = buff.get_event_count();
+        let mut event = mem::MaybeUninit::uninit();
+        
+        for j in 0..evcount {
+            message.bytes.clear();
+            unsafe { buff.get_event(event.as_mut_ptr(), j) };
+            let event = unsafe { event.assume_init() };
+            
+            for i in 0..event.size {
+                message.bytes.push(unsafe { *event.buffer.offset(i as isize) });
+            }
+            
+            message.timestamp = Client::get_time(); // this is in microseconds
+            (data.callback)(message.timestamp, &message.bytes, data.user_data.as_mut().unwrap());
+        }
+    }
+    
+    return 0;
+}
+
+struct OutputHandlerData {
+    port: Option<MidiPort>,
+    buff_size: Ringbuffer,
+    buff_message: Ringbuffer,
+}
+
+pub struct MidiOutput {
+    client: Option<Client>,
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiOutputPort {
+    name: CString
+}
+
+pub struct MidiOutputConnection {
+    handler_data: Box<OutputHandlerData>,
+    client: Option<Client>
+}
+
+impl MidiOutput {
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        let client = match Client::open(client_name, JackOpenOptions::NoStartServer) {
+            Ok(c) => c,
+            Err(_) => { return Err(InitError); } // TODO: maybe add message that Jack server might not be running
+        };
+        
+        Ok(MidiOutput {
+            client: Some(client),
+        })
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiOutputPort> {
+        let ports = self.client.as_ref().unwrap().get_midi_ports(PortFlags::PortIsInput);
+        let mut result = Vec::with_capacity(ports.count());
+        for i in 0..ports.count() {
+            result.push(::common::MidiOutputPort {
+                imp: MidiOutputPort {
+                    name: ports.get_c_name(i).into()
+                }
+            })
+        }
+        result
+    }
+    
+    pub fn port_count(&self) -> usize {
+        self.client.as_ref().unwrap().get_midi_ports(PortFlags::PortIsInput).count()
+    }
+    
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        Ok(port.name.to_string_lossy().into())
+    }
+    
+    fn activate_callback(&mut self) -> Box<OutputHandlerData> {
+        let handler_data = Box::new(OutputHandlerData {
+            port: None,
+            buff_size: Ringbuffer::new(OUTPUT_RINGBUFFER_SIZE),
+            buff_message: Ringbuffer::new(OUTPUT_RINGBUFFER_SIZE)
+        });
+        
+        let data_ptr = unsafe { mem::transmute_copy::<_, *mut OutputHandlerData>(&handler_data) };
+        
+        self.client.as_mut().unwrap().set_process_callback(handle_output, data_ptr as *mut c_void);
+        self.client.as_mut().unwrap().activate();
+        handler_data
+    }
+    
+    pub fn connect(mut self, port: &MidiOutputPort, port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        let mut handler_data = self.activate_callback();
+        
+        // Create port ...
+        let source_port = match self.client.as_mut().unwrap().register_midi_port(port_name, PortFlags::PortIsOutput) {
+            Ok(p) => p,
+            Err(()) => { return Err(ConnectError::other("could not register JACK port", self)); }
+        };
+        
+        // ... and connect it to the input
+        if let Err(_) = self.client.as_mut().unwrap().connect(source_port.get_name(), &port.name) {
+            return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self));
+        }
+        
+        handler_data.port = Some(source_port);
+        
+        Ok(MidiOutputConnection {
+            handler_data: handler_data,
+            client: self.client.take()
+        })
+    }
+    
+    pub fn create_virtual(
+        mut self, port_name: &str
+    ) -> Result<MidiOutputConnection, ConnectError<Self>> {
+        let mut handler_data = self.activate_callback();
+        
+        // Create port
+        let port = match self.client.as_mut().unwrap().register_midi_port(port_name, PortFlags::PortIsOutput) {
+            Ok(p) => p,
+            Err(()) => { return Err(ConnectError::other("could not register JACK port", self)); }
+        };
+        
+        handler_data.port = Some(port);
+        
+        Ok(MidiOutputConnection {
+            handler_data: handler_data,
+            client: self.client.take()
+        })
+    }
+}
+
+impl MidiOutputConnection {
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {
+        let nbytes = message.len();
+        
+        // Write full message to buffer
+        let written = self.handler_data.buff_message.write(message);
+        debug_assert!(written == nbytes, "not enough bytes written to ALSA ringbuffer `message`");
+        let nbytes_slice = unsafe { slice::from_raw_parts(&nbytes as *const usize as *const u8, mem::size_of_val(&nbytes)) }; 
+        let written = self.handler_data.buff_size.write(nbytes_slice);
+        debug_assert!(written == mem::size_of_val(&nbytes), "not enough bytes written to ALSA ringbuffer `size`");
+        Ok(())
+    }
+    
+    pub fn close(mut self) -> MidiOutput {
+        self.close_internal();
+        
+        MidiOutput {
+            client: self.client.take(),
+        }
+    }
+    
+    fn close_internal(&mut self) {
+        let port = self.handler_data.port.take().unwrap();
+        self.client.as_mut().unwrap().unregister_midi_port(port);
+        self.client.as_mut().unwrap().deactivate();
+    }
+}
+
+impl Drop for MidiOutputConnection {
+    fn drop(&mut self) {
+        if self.client.is_some() {
+            self.close_internal();
+        }
+    }
+}
+
+extern "C" fn handle_output(nframes: jack_nframes_t, arg: *mut c_void) -> i32 {
+    let data: &mut OutputHandlerData = unsafe { mem::transmute(arg) }; 
+    
+    // Is port created?
+    if let Some(ref port) = data.port {
+        let mut space: usize = 0;
+        
+        let mut buff = port.get_midi_buffer(nframes);
+        buff.clear();
+        
+        while data.buff_size.get_read_space() > 0 {
+            let read = data.buff_size.read(&mut space as *mut usize as *mut u8, mem::size_of::<usize>());
+            debug_assert!(read == mem::size_of::<usize>(), "not enough bytes read from `size` ringbuffer");
+            let midi_data = buff.event_reserve(0, space);
+            let read = data.buff_message.read(midi_data, space);
+            debug_assert!(read == space, "not enough bytes read from `message` ringbuffer");
+        }
+    }
+    
+    return 0;
+}
diff --git a/third_party/rust/midir/src/backend/jack/wrappers.rs b/third_party/rust/midir/src/backend/jack/wrappers.rs
new file mode 100644
index 0000000000..ef00e2d73f
--- /dev/null
+++ b/third_party/rust/midir/src/backend/jack/wrappers.rs
@@ -0,0 +1,250 @@
+#![allow(non_upper_case_globals, dead_code)]
+
+use std::{ptr, slice, str};
+use std::ffi::{CStr, CString};
+use std::ops::Index;
+
+use super::libc::{c_void, size_t};
+
+use super::jack_sys::{
+    jack_get_time,
+    jack_client_t,
+    jack_client_open,
+    jack_client_close,
+    jack_get_ports,
+    jack_port_t,
+    jack_port_register,
+    jack_port_unregister,
+    jack_port_name,
+    jack_free,
+    jack_activate,
+    jack_deactivate,
+    jack_nframes_t,
+    jack_set_process_callback,
+    jack_connect,
+    jack_port_get_buffer,
+    jack_midi_data_t,
+    jack_midi_get_event_count,
+    jack_midi_event_get,
+    jack_midi_event_t,
+    jack_midi_clear_buffer,
+    jack_midi_event_reserve,
+    jack_ringbuffer_t,
+    jack_ringbuffer_create,
+    jack_ringbuffer_read_space,
+    jack_ringbuffer_read,
+    jack_ringbuffer_free,
+    jack_ringbuffer_write,
+};
+
+pub const JACK_DEFAULT_MIDI_TYPE: &[u8] = b"8 bit raw midi\0";
+
+bitflags! {
+    pub struct JackOpenOptions: u32 {
+        const NoStartServer = 1;
+        const UseExactName = 2;
+        const ServerName = 4;
+        const SessionID = 32;
+    }
+}
+
+bitflags! {
+    pub struct PortFlags: u32 {
+        const PortIsInput = 1;
+        const PortIsOutput = 2;
+        const PortIsPhysical = 4;
+        const PortCanMonitor = 8;
+        const PortIsTerminal = 16;
+    }
+}
+
+// TODO: hide this type
+pub type ProcessCallback = extern "C" fn(nframes: jack_nframes_t, arg: *mut c_void) -> i32;
+
+pub struct Client {
+    p: *mut jack_client_t
+}
+
+unsafe impl Send for Client {}
+
+impl Client {
+    pub fn get_time() -> u64 {
+        unsafe { jack_get_time() }
+    }
+    
+    pub fn open(name: &str, options: JackOpenOptions) -> Result<Client, ()> {
+        let c_name = CString::new(name).ok().expect("client name must not contain null bytes");
+        let result = unsafe { jack_client_open(c_name.as_ptr(), options.bits(), ptr::null_mut()) };
+        if result.is_null() {
+            Err(())
+        } else {
+            Ok(Client { p: result })
+        }
+    }
+    
+    pub fn get_midi_ports(&self, flags: PortFlags) -> PortInfos {
+        let ports_ptr = unsafe { jack_get_ports(self.p, ptr::null_mut(), JACK_DEFAULT_MIDI_TYPE.as_ptr() as *const i8, flags.bits() as u64) };
+        let slice = if ports_ptr.is_null() {
+            &[]
+        } else {
+            unsafe { 
+                let count = (0isize..).find(|i| (*ports_ptr.offset(*i)).is_null()).unwrap() as usize;
+                slice::from_raw_parts(ports_ptr, count)
+            }
+        };
+        PortInfos { p: slice }
+    }
+    
+    pub fn register_midi_port(&mut self, name: &str, flags: PortFlags) -> Result<MidiPort, ()> {
+        let c_name = CString::new(name).ok().expect("port name must not contain null bytes");
+        let result = unsafe { jack_port_register(self.p, c_name.as_ptr(), JACK_DEFAULT_MIDI_TYPE.as_ptr() as *const i8, flags.bits() as u64, 0) };
+        if result.is_null() {
+            Err(())
+        } else {
+            Ok(MidiPort { p: result })
+        }
+    }
+    
+    /// This can not be implemented in Drop, because it needs a reference
+    /// to the client. But it consumes the MidiPort.
+    pub fn unregister_midi_port(&mut self, client: MidiPort) {
+        unsafe { jack_port_unregister(self.p, client.p) };
+    }
+    
+    pub fn activate(&mut self) {
+        unsafe { jack_activate(self.p) };
+    }
+    
+    pub fn deactivate(&mut self) {
+        unsafe { jack_deactivate(self.p) };
+    }
+    
+    /// The code in the supplied function must be suitable for real-time
+    /// execution. That means that it cannot call functions that might block
+    /// for a long time. This includes all I/O functions (disk, TTY, network),
+    /// malloc, free, printf, pthread_mutex_lock, sleep, wait, poll, select,
+    /// pthread_join, pthread_cond_wait, etc, etc.
+    pub fn set_process_callback(&mut self, callback: ProcessCallback, data: *mut c_void) {
+        unsafe { jack_set_process_callback(self.p, Some(callback), data) };
+    }
+    
+    pub fn connect(&mut self, source_port: &CStr, destination_port: &CStr) -> Result<(), ()> {
+        let rc = unsafe { jack_connect(self.p, source_port.as_ptr(), destination_port.as_ptr()) };
+        if rc == 0 {
+            Ok(())
+        } else {
+            Err(()) // TODO: maybe handle EEXIST explicitly
+        }
+    }
+}
+
+impl Drop for Client {
+    fn drop(&mut self) {
+        unsafe { jack_client_close(self.p) };
+    }
+}
+
+pub struct PortInfos<'a> {
+    p: &'a[*const i8],
+}
+
+unsafe impl<'a> Send for PortInfos<'a> {}
+
+impl<'a> PortInfos<'a> {
+    pub fn count(&self) -> usize {
+        self.p.len()
+    }
+    
+    pub fn get_c_name(&self, index: usize) -> &CStr {
+        let ptr = self.p[index];
+        unsafe { CStr::from_ptr(ptr) }
+    }
+}
+
+impl<'a> Index<usize> for PortInfos<'a> {
+    type Output = str;
+    
+    fn index(&self, index: usize) -> &Self::Output { 
+        let slice = self.get_c_name(index).to_bytes();
+        str::from_utf8(slice).ok().expect("Error converting port name to UTF8")
+    }
+}
+
+impl<'a> Drop for PortInfos<'a> {
+    fn drop(&mut self) {
+        if self.p.len() > 0 {
+            unsafe { jack_free(self.p.as_ptr() as *mut _) }
+        }
+    }
+}
+
+pub struct MidiPort {
+    p: *mut jack_port_t
+}
+
+unsafe impl Send for MidiPort {}
+
+impl MidiPort {
+    pub fn get_name(&self) -> &CStr {
+        unsafe { CStr::from_ptr(jack_port_name(self.p)) }
+    }
+    
+    pub fn get_midi_buffer(&self, nframes: jack_nframes_t) -> MidiBuffer {
+        let buf = unsafe { jack_port_get_buffer(self.p, nframes) };
+        MidiBuffer { p: buf }
+    }
+}
+
+pub struct MidiBuffer {
+    p: *mut c_void
+}
+
+impl MidiBuffer {
+    pub fn get_event_count(&self) -> u32 {
+        unsafe { jack_midi_get_event_count(self.p) }
+    }
+    
+    pub unsafe fn get_event(&self, ev: *mut jack_midi_event_t, index: u32) {
+        jack_midi_event_get(ev, self.p, index);
+    }
+    
+    pub fn clear(&mut self) {
+        unsafe { jack_midi_clear_buffer(self.p) }
+    }
+    
+    pub fn event_reserve(&mut self, time: jack_nframes_t, data_size: usize) -> *mut jack_midi_data_t {
+        unsafe { jack_midi_event_reserve(self.p, time, data_size as size_t) }
+    }
+}
+
+pub struct Ringbuffer {
+    p: *mut jack_ringbuffer_t
+}
+
+unsafe impl Send for Ringbuffer {}
+
+impl Ringbuffer {
+    pub fn new(size: usize) -> Ringbuffer {
+        let result = unsafe { jack_ringbuffer_create(size as size_t) };
+        Ringbuffer { p: result }
+    }
+    
+    pub fn get_read_space(&self) -> usize {
+        unsafe { jack_ringbuffer_read_space(self.p) as usize }
+    }
+    
+    pub fn read(&mut self, destination: *mut u8, count: usize) -> usize {
+        let bytes_read = unsafe { jack_ringbuffer_read(self.p, destination as *mut i8, count as size_t) };
+        bytes_read as usize 
+    }
+    
+    pub fn write(&mut self, source: &[u8]) -> usize {
+        unsafe { jack_ringbuffer_write(self.p, source.as_ptr() as *const i8, source.len() as size_t) as usize }
+    }
+}
+
+impl Drop for Ringbuffer{
+    fn drop(&mut self) {
+        unsafe { jack_ringbuffer_free(self.p) }
+    }
+}
\ No newline at end of file
diff --git a/third_party/rust/midir/src/backend/mod.rs b/third_party/rust/midir/src/backend/mod.rs
new file mode 100644
index 0000000000..2940daeeff
--- /dev/null
+++ b/third_party/rust/midir/src/backend/mod.rs
@@ -0,0 +1,22 @@
+// This module is not public
+
+// TODO: improve feature selection (make sure that there is always exactly one implementation, or enable dynamic backend selection)
+// TODO: allow to disable build dependency on ALSA
+
+#[cfg(all(target_os="windows", not(feature = "winrt")))] mod winmm;
+#[cfg(all(target_os="windows", not(feature = "winrt")))] pub use self::winmm::*;
+
+#[cfg(all(target_os="windows", feature = "winrt"))] mod winrt;
+#[cfg(all(target_os="windows", feature = "winrt"))] pub use self::winrt::*;
+
+#[cfg(all(target_os="macos", not(feature = "jack")))] mod coremidi;
+#[cfg(all(target_os="macos", not(feature = "jack")))] pub use self::coremidi::*;
+
+#[cfg(all(target_os="linux", not(feature = "jack")))] mod alsa;
+#[cfg(all(target_os="linux", not(feature = "jack")))] pub use self::alsa::*;
+
+#[cfg(all(feature = "jack", not(target_os="windows")))] mod jack;
+#[cfg(all(feature = "jack", not(target_os="windows")))] pub use self::jack::*;
+
+#[cfg(target_arch="wasm32")] mod webmidi;
+#[cfg(target_arch="wasm32")] pub use self::webmidi::*;
diff --git a/third_party/rust/midir/src/backend/webmidi/mod.rs b/third_party/rust/midir/src/backend/webmidi/mod.rs
new file mode 100644
index 0000000000..b76f0b3617
--- /dev/null
+++ b/third_party/rust/midir/src/backend/webmidi/mod.rs
@@ -0,0 +1,250 @@
+//! Web MIDI Backend.
+//! 
+//! Reference:
+//! * [W3C Editor's Draft](https://webaudio.github.io/web-midi-api/)
+//! * [MDN web docs](https://developer.mozilla.org/en-US/docs/Web/API/MIDIAccess)
+
+extern crate js_sys;
+extern crate wasm_bindgen;
+extern crate web_sys;
+
+use self::js_sys::{Map, Promise, Uint8Array};
+use self::wasm_bindgen::prelude::*;
+use self::wasm_bindgen::JsCast;
+use self::web_sys::{MidiAccess, MidiOptions, MidiMessageEvent};
+
+use std::cell::RefCell;
+use std::sync::{Arc, Mutex};
+
+use ::errors::*;
+use ::Ignore;
+
+
+
+thread_local! {
+    static STATIC : RefCell<Static> = RefCell::new(Static::new());
+}
+
+struct Static {
+    pub access:         Option<MidiAccess>,
+    pub request:        Option<Promise>,
+    pub ever_requested: bool,
+
+    pub on_ok:          Closure<dyn FnMut(JsValue)>,
+    pub on_err:         Closure<dyn FnMut(JsValue)>,
+}
+
+impl Static {
+    pub fn new() -> Self {
+        let mut s = Self {
+            access:         None,
+            request:        None,
+            ever_requested: false,
+
+            on_ok: Closure::wrap(Box::new(|access| {
+                STATIC.with(|s|{
+                    let mut s = s.borrow_mut();
+                    let access : MidiAccess = access.dyn_into().unwrap();
+                    s.request = None;
+                    s.access = Some(access);
+                });
+            })),
+            on_err: Closure::wrap(Box::new(|_error| {
+                STATIC.with(|s|{
+                    let mut s = s.borrow_mut();
+                    s.request = None;
+                });
+            })),
+        };
+        // Some notes on sysex behavior:
+        //  1) Some devices (but not all!) may work without sysex
+        //  2) Chrome will only prompt the end user to grant permission if they requested sysex permissions for now...
+        //      but that's changing soon for "security reasons" (reduced fingerprinting? poorly tested drivers?):
+        //      https://www.chromestatus.com/feature/5138066234671104
+        //
+        //  I've chosen to hardcode sysex=true here, since that'll be compatible with more devices, *and* should change
+        //  less behavior when Chrome's changes land.
+        s.request_midi_access(true);
+        s
+    }
+
+    fn request_midi_access(&mut self, sysex: bool) {
+        self.ever_requested = true;
+        if self.access.is_some() { return; } // Already have access
+        if self.request.is_some() { return; } // Mid-request already
+        let window = if let Some(w) = web_sys::window() { w } else { return; };
+
+        let _request = match window.navigator().request_midi_access_with_options(MidiOptions::new().sysex(sysex)) {
+            Ok(p) => { self.request = Some(p.then2(&self.on_ok, &self.on_err)); },
+            Err(_) => { return; } // node.js? brower doesn't support webmidi? other?
+        };
+    }
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiInputPort {
+    input: web_sys::MidiInput,
+}
+
+pub struct MidiInput {
+    ignore_flags: Ignore
+}
+
+impl MidiInput {
+    pub fn new(_client_name: &str) -> Result<Self, InitError> {
+        STATIC.with(|_|{});
+        Ok(MidiInput { ignore_flags: Ignore::None })
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiInputPort> {
+        STATIC.with(|s|{
+            let mut v = Vec::new();
+            let s = s.borrow();
+            if let Some(access) = s.access.as_ref() {
+                let inputs : Map = access.inputs().unchecked_into();
+                inputs.for_each(&mut |value, _|{
+                    v.push(::common::MidiInputPort {
+                        imp: MidiInputPort { input: value.dyn_into().unwrap() }
+                    });
+                });
+            }
+            v
+        })
+    }
+
+    pub fn ignore(&mut self, flags: Ignore) {
+        self.ignore_flags = flags;
+    }
+
+    pub fn port_count(&self) -> usize {
+        STATIC.with(|s| {
+            let s = s.borrow();
+            s.access.as_ref().map(|access| access.inputs().unchecked_into::<Map>().size() as usize).unwrap_or(0)
+        })
+    }
+
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        Ok(port.input.name().unwrap_or_else(|| port.input.id()))
+    }
+
+    pub fn connect<F, T: Send + 'static>(
+        self, port: &MidiInputPort, _port_name: &str, mut callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static
+    {
+        let input = port.input.clone();
+        let _ = input.open(); // NOTE: asyncronous!
+
+        let ignore_flags = self.ignore_flags;
+        let user_data = Arc::new(Mutex::new(Some(data)));
+
+        let closure = {
+            let user_data = user_data.clone();
+
+            let closure = Closure::wrap(Box::new(move |event: MidiMessageEvent| {
+                let time = (event.time_stamp() * 1000.0) as u64; // ms -> us
+                let buffer = event.data().unwrap();
+
+                let status = buffer[0];
+                if !(status == 0xF0 && ignore_flags.contains(Ignore::Sysex) ||
+                        status == 0xF1 && ignore_flags.contains(Ignore::Time) ||
+                        status == 0xF8 && ignore_flags.contains(Ignore::Time) ||
+                        status == 0xFE && ignore_flags.contains(Ignore::ActiveSense))
+                {
+                    callback(time, &buffer[..], user_data.lock().unwrap().as_mut().unwrap());
+                }
+            }) as Box<dyn FnMut(MidiMessageEvent)>);
+
+            input.set_onmidimessage(Some(closure.as_ref().unchecked_ref()));
+
+            closure
+        };
+
+        Ok(MidiInputConnection { ignore_flags, input, user_data, closure })
+    }
+}
+
+pub struct MidiInputConnection<T> {
+    ignore_flags:   Ignore,
+    input:          web_sys::MidiInput,
+    user_data:      Arc<Mutex<Option<T>>>,
+    #[allow(dead_code)] // Must be kept alive until we decide to unregister from input
+    closure:        Closure<dyn FnMut(MidiMessageEvent)>,
+}
+
+impl<T> MidiInputConnection<T> {
+    pub fn close(self) -> (MidiInput, T) {
+        let Self { ignore_flags, input, user_data, .. } = self;
+
+        input.set_onmidimessage(None);
+        let mut user_data = user_data.lock().unwrap();
+
+        (
+            MidiInput { ignore_flags },
+            user_data.take().unwrap()
+        )
+    }
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiOutputPort {
+    output: web_sys::MidiOutput,
+}
+
+pub struct MidiOutput {
+}
+
+impl MidiOutput {
+    pub fn new(_client_name: &str) -> Result<Self, InitError> {
+        STATIC.with(|_|{});
+        Ok(MidiOutput {})
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiOutputPort> {
+        STATIC.with(|s|{
+            let mut v = Vec::new();
+            let s = s.borrow();
+            if let Some(access) = s.access.as_ref() {
+                access.outputs().unchecked_into::<Map>().for_each(&mut |value, _|{
+                    v.push(::common::MidiOutputPort {
+                        imp: MidiOutputPort { output: value.dyn_into().unwrap() }
+                    });
+                });
+            }
+            v
+        })
+    }
+
+    pub fn port_count(&self) -> usize {
+        STATIC.with(|s|{
+            let s = s.borrow();
+            s.access.as_ref().map(|access| access.outputs().unchecked_into::<Map>().size() as usize).unwrap_or(0)
+        })
+    }
+
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        Ok(port.output.name().unwrap_or_else(|| port.output.id()))
+    }
+
+    pub fn connect(self, port: &MidiOutputPort, _port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        let _ = port.output.open(); // NOTE: asyncronous!
+        Ok(MidiOutputConnection{
+            output: port.output.clone()
+        })
+    }
+}
+
+pub struct MidiOutputConnection {
+    output: web_sys::MidiOutput,
+}
+
+impl MidiOutputConnection {
+    pub fn close(self) -> MidiOutput {
+        let _ = self.output.close(); // NOTE: asyncronous!
+        MidiOutput {}
+    }
+    
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {
+        self.output.send(unsafe { Uint8Array::view(message) }.as_ref()).map_err(|_| SendError::Other("JavaScript exception"))
+    }
+}
diff --git a/third_party/rust/midir/src/backend/winmm/handler.rs b/third_party/rust/midir/src/backend/winmm/handler.rs
new file mode 100644
index 0000000000..b04d2ee908
--- /dev/null
+++ b/third_party/rust/midir/src/backend/winmm/handler.rs
@@ -0,0 +1,85 @@
+use std::{mem, slice};
+use std::io::{Write, stderr};
+
+use super::winapi::shared::basetsd::DWORD_PTR;
+use super::winapi::shared::minwindef::{DWORD, UINT};
+use super::winapi::um::mmeapi::midiInAddBuffer;
+use super::winapi::um::mmsystem::{HMIDIIN, MIDIHDR, MMSYSERR_NOERROR, MM_MIM_DATA,
+                                  MM_MIM_LONGDATA, MM_MIM_LONGERROR};
+use super::HandlerData;
+use Ignore;
+
+pub extern "system" fn handle_input<T>(_: HMIDIIN,
+                input_status: UINT, 
+                instance_ptr: DWORD_PTR,
+                midi_message: DWORD_PTR,
+                timestamp: DWORD) {
+    if input_status != MM_MIM_DATA && input_status != MM_MIM_LONGDATA && input_status != MM_MIM_LONGERROR { return; }
+    
+    let data: &mut HandlerData<T> = unsafe { &mut *(instance_ptr as *mut HandlerData<T>) };
+    
+    // Calculate time stamp.
+    data.message.timestamp = timestamp as u64 * 1000; // milliseconds -> microseconds
+    
+    if input_status == MM_MIM_DATA { // Channel or system message
+        // Make sure the first byte is a status byte.
+        let status: u8 = (midi_message & 0x000000FF) as u8;
+        if !(status & 0x80 != 0) { return; }
+        
+        // Determine the number of bytes in the MIDI message.
+        let nbytes: u16 = if status < 0xC0 { 3 }
+        else if status < 0xE0 { 2 }
+        else if status < 0xF0 { 3 }
+        else if status == 0xF1 {
+            if data.ignore_flags.contains(Ignore::Time) { return; }
+            else  { 2 }
+        } else if status == 0xF2 { 3 }
+        else if status == 0xF3 { 2 }
+        else if status == 0xF8 && (data.ignore_flags.contains(Ignore::Time)) {
+            // A MIDI timing tick message and we're ignoring it.
+            return;
+        } else if status == 0xFE && (data.ignore_flags.contains(Ignore::ActiveSense)) {
+            // A MIDI active sensing message and we're ignoring it.
+            return;
+        } else { 1 };
+        
+        // Copy bytes to our MIDI message.
+        let ptr = (&midi_message) as *const DWORD_PTR as *const u8;
+        let bytes: &[u8] = unsafe { slice::from_raw_parts(ptr, nbytes as usize) };
+        data.message.bytes.extend_from_slice(bytes);
+    } else { // Sysex message (MIM_LONGDATA or MIM_LONGERROR)
+        let sysex = unsafe { &*(midi_message as *const MIDIHDR) };
+        if !data.ignore_flags.contains(Ignore::Sysex) && input_status != MM_MIM_LONGERROR {
+            // Sysex message and we're not ignoring it
+            let bytes: &[u8] = unsafe { slice::from_raw_parts(sysex.lpData as *const u8, sysex.dwBytesRecorded as usize) };
+            data.message.bytes.extend_from_slice(bytes);
+            // TODO: If sysex messages are longer than RT_SYSEX_BUFFER_SIZE, they
+            //       are split in chunks. We could reassemble a single message.
+        }
+    
+        // The WinMM API requires that the sysex buffer be requeued after
+        // input of each sysex message.  Even if we are ignoring sysex
+        // messages, we still need to requeue the buffer in case the user
+        // decides to not ignore sysex messages in the future.  However,
+        // it seems that WinMM calls this function with an empty sysex
+        // buffer when an application closes and in this case, we should
+        // avoid requeueing it, else the computer suddenly reboots after
+        // one or two minutes.
+        if (unsafe {*data.sysex_buffer.0[sysex.dwUser as usize]}).dwBytesRecorded > 0 {
+        //if ( sysex->dwBytesRecorded > 0 ) {
+            let in_handle = data.in_handle.as_ref().unwrap().0.lock().unwrap();
+            let result = unsafe { midiInAddBuffer(*in_handle, data.sysex_buffer.0[sysex.dwUser as usize], mem::size_of::<MIDIHDR>() as u32) };
+            drop(in_handle);
+            if result != MMSYSERR_NOERROR {
+                let _ = writeln!(stderr(), "\nError in handle_input: Requeuing WinMM input sysex buffer failed.\n");
+            }
+            
+            if data.ignore_flags.contains(Ignore::Sysex) { return; }
+        } else { return; }
+    }
+    
+    (data.callback)(data.message.timestamp, &data.message.bytes, data.user_data.as_mut().unwrap());   
+    
+    // Clear the vector for the next input message.
+    data.message.bytes.clear();
+}
\ No newline at end of file
diff --git a/third_party/rust/midir/src/backend/winmm/mod.rs b/third_party/rust/midir/src/backend/winmm/mod.rs
new file mode 100644
index 0000000000..2d20004ece
--- /dev/null
+++ b/third_party/rust/midir/src/backend/winmm/mod.rs
@@ -0,0 +1,536 @@
+extern crate winapi;
+
+use std::{mem, ptr, slice};
+use std::ffi::OsString;
+use std::os::windows::ffi::OsStringExt;
+use std::sync::Mutex;
+use std::io::{Write, stderr};
+use std::thread::sleep;
+use std::time::Duration;
+use memalloc::{allocate, deallocate};
+use std::mem::MaybeUninit;
+use std::ptr::null_mut;
+
+use self::winapi::shared::basetsd::{DWORD_PTR, UINT_PTR};
+use self::winapi::shared::minwindef::{DWORD, UINT};
+
+use self::winapi::um::mmeapi::{midiInAddBuffer, midiInClose, midiInGetDevCapsW, midiInGetNumDevs,
+                               midiInOpen, midiInPrepareHeader, midiInReset, midiInStart,
+                               midiInStop, midiInUnprepareHeader, midiOutClose,
+                               midiOutGetDevCapsW, midiOutGetNumDevs, midiOutLongMsg, midiOutOpen,
+                               midiOutPrepareHeader, midiOutReset, midiOutShortMsg,
+                               midiOutUnprepareHeader};
+
+use self::winapi::um::mmsystem::{CALLBACK_FUNCTION, CALLBACK_NULL, HMIDIIN, HMIDIOUT, LPMIDIHDR,
+                                 MIDIERR_NOTREADY, MIDIERR_STILLPLAYING, MIDIHDR, MIDIINCAPSW,
+                                 MIDIOUTCAPSW, MMSYSERR_BADDEVICEID, MMSYSERR_NOERROR, MMSYSERR_ALLOCATED};
+
+use {Ignore, MidiMessage};
+use errors::*;
+
+mod handler;
+
+const DRV_QUERYDEVICEINTERFACE: UINT = 0x80c;
+const DRV_QUERYDEVICEINTERFACESIZE: UINT = 0x80d;
+
+const RT_SYSEX_BUFFER_SIZE: usize = 1024;
+const RT_SYSEX_BUFFER_COUNT: usize = 4;
+
+// helper for string conversion
+fn from_wide_ptr(ptr: *const u16, max_len: usize) -> OsString {
+    unsafe {
+        assert!(!ptr.is_null());
+        let len = (0..max_len as isize).position(|i| *ptr.offset(i) == 0).unwrap();
+        let slice = slice::from_raw_parts(ptr, len);
+        OsString::from_wide(slice)
+    }
+}
+
+#[derive(Debug)]
+pub struct MidiInput {
+    ignore_flags: Ignore
+}
+
+#[derive(Clone)]
+pub struct MidiInputPort {
+    name: String,
+    interface_id: Box<[u16]>
+}
+
+impl PartialEq for MidiInputPort {
+    fn eq(&self, other: &Self) -> bool {
+        self.interface_id == other.interface_id
+    }
+}
+
+pub struct MidiInputConnection<T> {
+    handler_data: Box<HandlerData<T>>,
+}
+
+impl MidiInputPort {
+    pub fn count() -> UINT {
+        unsafe { midiInGetNumDevs() }
+    }
+
+    fn interface_id(port_number: UINT) -> Result<Box<[u16]>, PortInfoError> {
+        let mut buffer_size: winapi::shared::minwindef::ULONG = 0;
+        let result = unsafe { winapi::um::mmeapi::midiInMessage(port_number as HMIDIIN, DRV_QUERYDEVICEINTERFACESIZE, &mut buffer_size as *mut _ as DWORD_PTR, 0) };
+        if result == MMSYSERR_BADDEVICEID {
+            return Err(PortInfoError::PortNumberOutOfRange)
+        } else if result != MMSYSERR_NOERROR {
+            return Err(PortInfoError::CannotRetrievePortName)
+        }
+        let mut buffer = Vec::<u16>::with_capacity(buffer_size as usize / 2);
+        unsafe {
+            let result = winapi::um::mmeapi::midiInMessage(port_number as HMIDIIN, DRV_QUERYDEVICEINTERFACE, buffer.as_mut_ptr() as DWORD_PTR, buffer_size as DWORD_PTR);
+            if result == MMSYSERR_BADDEVICEID {
+                return Err(PortInfoError::PortNumberOutOfRange)
+            } else if result != MMSYSERR_NOERROR {
+                return Err(PortInfoError::CannotRetrievePortName)
+            }
+            buffer.set_len(buffer_size as usize / 2);
+        }
+        //println!("{}", from_wide_ptr(buffer.as_ptr(), buffer.len()).to_string_lossy().into_owned());
+        Ok(buffer.into_boxed_slice())
+    }
+    
+    fn name(port_number: UINT) -> Result<String, PortInfoError> {
+        let mut device_caps: MaybeUninit<MIDIINCAPSW> = MaybeUninit::uninit();
+        let result = unsafe { midiInGetDevCapsW(port_number as UINT_PTR, device_caps.as_mut_ptr(), mem::size_of::<MIDIINCAPSW>() as u32) };
+        if result == MMSYSERR_BADDEVICEID {
+            return Err(PortInfoError::PortNumberOutOfRange)
+        } else if result != MMSYSERR_NOERROR {
+            return Err(PortInfoError::CannotRetrievePortName)
+        }
+        let device_caps = unsafe { device_caps.assume_init() };
+        let pname = device_caps.szPname;
+        let output = from_wide_ptr(pname.as_ptr(), pname.len()).to_string_lossy().into_owned();
+        Ok(output)
+    }
+
+    fn from_port_number(port_number: UINT) -> Result<Self, PortInfoError> {
+        Ok(MidiInputPort {
+            name: Self::name(port_number)?,
+            interface_id: Self::interface_id(port_number)?
+        })
+    }
+
+    fn current_port_number(&self) -> Option<UINT> {
+        for i in 0..Self::count() {
+            if let Ok(name) = Self::name(i) {
+                if name != self.name { continue; }
+                if let Ok(id) = Self::interface_id(i) {
+                    if id == self.interface_id {
+                        return Some(i);
+                    }
+                }
+            }
+        }
+        None
+    }
+}
+
+struct SysexBuffer([LPMIDIHDR; RT_SYSEX_BUFFER_COUNT]);
+unsafe impl Send for SysexBuffer {}
+
+struct MidiInHandle(Mutex<HMIDIIN>);
+unsafe impl Send for MidiInHandle {}
+
+/// This is all the data that is stored on the heap as long as a connection
+/// is opened and passed to the callback handler.
+///
+/// It is important that `user_data` is the last field to not influence
+/// offsets after monomorphization.
+struct HandlerData<T> {
+    message: MidiMessage,
+    sysex_buffer: SysexBuffer,
+    in_handle: Option<MidiInHandle>,
+    ignore_flags: Ignore,
+    callback: Box<dyn FnMut(u64, &[u8], &mut T) + Send + 'static>,
+    user_data: Option<T>
+}
+
+impl MidiInput {
+    pub fn new(_client_name: &str) -> Result<Self, InitError> {
+        Ok(MidiInput { ignore_flags: Ignore::None })
+    }
+    
+    pub fn ignore(&mut self, flags: Ignore) {
+        self.ignore_flags = flags;
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiInputPort> {
+        let count = MidiInputPort::count();
+        let mut result = Vec::with_capacity(count as usize);
+        for i in 0..count {
+            let port = match MidiInputPort::from_port_number(i) {
+                Ok(p) => p,
+                Err(_) => continue
+            };
+            result.push(::common::MidiInputPort {
+                imp: port
+            });
+        }
+        result
+    }
+    
+    pub fn port_count(&self) -> usize {
+        MidiInputPort::count() as usize
+    }
+
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        Ok(port.name.clone())
+    }
+    
+    pub fn connect<F, T: Send>(
+        self, port: &MidiInputPort, _port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        
+        let port_number = match port.current_port_number() {
+            Some(p) => p,
+            None => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+        };
+
+        let mut handler_data = Box::new(HandlerData {
+            message: MidiMessage::new(),
+            sysex_buffer: SysexBuffer([null_mut(); RT_SYSEX_BUFFER_COUNT]),
+            in_handle: None,
+            ignore_flags: self.ignore_flags,
+            callback: Box::new(callback),
+            user_data: Some(data)
+        });
+        
+        let mut in_handle: MaybeUninit<HMIDIIN> = MaybeUninit::uninit();
+        let handler_data_ptr: *mut HandlerData<T> = &mut *handler_data;
+        let result = unsafe { midiInOpen(in_handle.as_mut_ptr(),
+                        port_number as UINT,
+                        handler::handle_input::<T> as DWORD_PTR,
+                        handler_data_ptr as DWORD_PTR,
+                        CALLBACK_FUNCTION) };
+        if result == MMSYSERR_ALLOCATED { 
+            return Err(ConnectError::other("could not create Windows MM MIDI input port (MMSYSERR_ALLOCATED)", self));
+        } else if result != MMSYSERR_NOERROR {
+            return Err(ConnectError::other("could not create Windows MM MIDI input port", self));
+        }
+        let in_handle = unsafe { in_handle.assume_init() };
+
+        // Allocate and init the sysex buffers.
+        for i in 0..RT_SYSEX_BUFFER_COUNT {
+            handler_data.sysex_buffer.0[i] = Box::into_raw(Box::new(MIDIHDR {
+                lpData: unsafe { allocate(RT_SYSEX_BUFFER_SIZE/*, mem::align_of::<u8>()*/) } as *mut i8,
+                dwBufferLength: RT_SYSEX_BUFFER_SIZE as u32,
+                dwBytesRecorded: 0,
+                dwUser: i as DWORD_PTR, // We use the dwUser parameter as buffer indicator
+                dwFlags: 0,
+                lpNext: ptr::null_mut(),
+                reserved: 0,
+                dwOffset: 0,
+                dwReserved: unsafe { mem::zeroed() },
+            }));
+            
+            // TODO: are those buffers ever freed if an error occurs here (altough these calls probably only fail with out-of-memory)?
+            // TODO: close port in case of error?
+            
+            let result = unsafe { midiInPrepareHeader(in_handle, handler_data.sysex_buffer.0[i], mem::size_of::<MIDIHDR>() as u32) };
+            if result != MMSYSERR_NOERROR {
+                return Err(ConnectError::other("could not initialize Windows MM MIDI input port (PrepareHeader)", self));
+            }
+            
+            // Register the buffer.
+            let result = unsafe { midiInAddBuffer(in_handle, handler_data.sysex_buffer.0[i], mem::size_of::<MIDIHDR>() as u32) };
+            if result != MMSYSERR_NOERROR {
+                return Err(ConnectError::other("could not initialize Windows MM MIDI input port (AddBuffer)", self));
+            }            
+        }
+        
+        handler_data.in_handle = Some(MidiInHandle(Mutex::new(in_handle)));
+        
+        // We can safely access (a copy of) `in_handle` here, although
+        // it has been copied into the Mutex already, because the callback
+        // has not been called yet.
+        let result = unsafe { midiInStart(in_handle) };
+        if result != MMSYSERR_NOERROR {
+            unsafe { midiInClose(in_handle) };
+            return Err(ConnectError::other("could not start Windows MM MIDI input port", self));
+        }
+        
+        Ok(MidiInputConnection {
+            handler_data: handler_data
+        })
+    }
+}
+
+impl<T> MidiInputConnection<T> {
+    pub fn close(mut self) -> (MidiInput, T) {
+        self.close_internal();
+        
+        (MidiInput {
+            ignore_flags: self.handler_data.ignore_flags,
+        }, self.handler_data.user_data.take().unwrap())
+    }
+    
+    fn close_internal(&mut self) {
+        // for information about his lock, see https://groups.google.com/forum/#!topic/mididev/6OUjHutMpEo
+        let in_handle_lock = self.handler_data.in_handle.as_ref().unwrap().0.lock().unwrap();
+        
+        // TODO: Call both reset and stop here? The difference seems to be that
+        //       reset "returns all pending input buffers to the callback function"
+        unsafe {
+            midiInReset(*in_handle_lock);
+            midiInStop(*in_handle_lock);
+        }
+        
+        for i in 0..RT_SYSEX_BUFFER_COUNT {
+            let result;
+            unsafe {
+                result = midiInUnprepareHeader(*in_handle_lock, self.handler_data.sysex_buffer.0[i], mem::size_of::<MIDIHDR>() as u32);
+                deallocate((*self.handler_data.sysex_buffer.0[i]).lpData as *mut u8, RT_SYSEX_BUFFER_SIZE/*, mem::align_of::<u8>()*/);
+                // recreate the Box so that it will be dropped/deallocated at the end of this scope
+                let _ = Box::from_raw(self.handler_data.sysex_buffer.0[i]);
+            }
+            
+            if result != MMSYSERR_NOERROR {
+                let _ = writeln!(stderr(), "Warning: Ignoring error shutting down Windows MM input port (UnprepareHeader).");
+            }
+        }
+        
+        unsafe { midiInClose(*in_handle_lock) };
+    }
+}
+
+impl<T> Drop for MidiInputConnection<T> {
+    fn drop(&mut self) {
+        // If user_data has been emptied, we know that we already have closed the connection
+        if self.handler_data.user_data.is_some() {
+            self.close_internal()
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct MidiOutput;
+
+#[derive(Clone)]
+pub struct MidiOutputPort {
+    name: String,
+    interface_id: Box<[u16]>
+}
+
+impl PartialEq for MidiOutputPort {
+    fn eq(&self, other: &Self) -> bool {
+        self.interface_id == other.interface_id
+    }
+}
+
+pub struct MidiOutputConnection {
+    out_handle: HMIDIOUT,
+}
+
+unsafe impl Send for MidiOutputConnection {}
+
+impl MidiOutputPort {
+    pub fn count() -> UINT {
+        unsafe { midiOutGetNumDevs() }
+    }
+
+    fn interface_id(port_number: UINT) -> Result<Box<[u16]>, PortInfoError> {
+        let mut buffer_size: winapi::shared::minwindef::ULONG = 0;
+        let result = unsafe { winapi::um::mmeapi::midiOutMessage(port_number as HMIDIOUT, DRV_QUERYDEVICEINTERFACESIZE, &mut buffer_size as *mut _ as DWORD_PTR, 0) };
+        if result == MMSYSERR_BADDEVICEID {
+            return Err(PortInfoError::PortNumberOutOfRange)
+        } else if result != MMSYSERR_NOERROR {
+            return Err(PortInfoError::CannotRetrievePortName)
+        }
+        let mut buffer = Vec::<u16>::with_capacity(buffer_size as usize / 2);
+        unsafe {
+            let result = winapi::um::mmeapi::midiOutMessage(port_number as HMIDIOUT, DRV_QUERYDEVICEINTERFACE, buffer.as_mut_ptr() as DWORD_PTR, buffer_size as DWORD_PTR);
+            if result == MMSYSERR_BADDEVICEID {
+                return Err(PortInfoError::PortNumberOutOfRange)
+            } else if result != MMSYSERR_NOERROR {
+                return Err(PortInfoError::CannotRetrievePortName)
+            }
+            buffer.set_len(buffer_size as usize / 2);
+        }
+        //println!("{}", from_wide_ptr(buffer.as_ptr(), buffer.len()).to_string_lossy().into_owned());
+        Ok(buffer.into_boxed_slice())
+    }
+    
+    fn name(port_number: UINT) -> Result<String, PortInfoError> {
+        let mut device_caps: MaybeUninit<MIDIOUTCAPSW> = MaybeUninit::uninit();
+        let result = unsafe { midiOutGetDevCapsW(port_number as UINT_PTR, device_caps.as_mut_ptr(), mem::size_of::<MIDIOUTCAPSW>() as u32) };
+        if result == MMSYSERR_BADDEVICEID {
+            return Err(PortInfoError::PortNumberOutOfRange)
+        } else if result != MMSYSERR_NOERROR {
+            return Err(PortInfoError::CannotRetrievePortName)
+        }
+        let device_caps = unsafe { device_caps.assume_init() };
+        let pname = device_caps.szPname;
+        let output = from_wide_ptr(pname.as_ptr(), pname.len()).to_string_lossy().into_owned();
+        Ok(output)
+    }
+
+    fn from_port_number(port_number: UINT) -> Result<Self, PortInfoError> {
+        Ok(MidiOutputPort {
+            name: Self::name(port_number)?,
+            interface_id: Self::interface_id(port_number)?
+        })
+    }
+
+    fn current_port_number(&self) -> Option<UINT> {
+        for i in 0..Self::count() {
+            if let Ok(name) = Self::name(i) {
+                if name != self.name { continue; }
+                if let Ok(id) = Self::interface_id(i) {
+                    if id == self.interface_id {
+                        return Some(i);
+                    }
+                }
+            }
+        }
+        None
+    }
+}
+
+impl MidiOutput {
+    pub fn new(_client_name: &str) -> Result<Self, InitError> {
+        Ok(MidiOutput)
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiOutputPort> {
+        let count = MidiOutputPort::count();
+        let mut result = Vec::with_capacity(count as usize);
+        for i in 0..count {
+            let port = match MidiOutputPort::from_port_number(i) {
+                Ok(p) => p,
+                Err(_) => continue
+            };
+            result.push(::common::MidiOutputPort {
+                imp: port
+            });
+        }
+        result
+    }
+    
+    pub fn port_count(&self) -> usize {
+        MidiOutputPort::count() as usize
+    }
+
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        Ok(port.name.clone())
+    }
+    
+    pub fn connect(self, port: &MidiOutputPort, _port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        let port_number = match port.current_port_number() {
+            Some(p) => p,
+            None => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+        };
+        let mut out_handle: MaybeUninit<HMIDIOUT> = MaybeUninit::uninit();
+        let result = unsafe { midiOutOpen(out_handle.as_mut_ptr(), port_number as UINT, 0, 0, CALLBACK_NULL) };
+        if result == MMSYSERR_ALLOCATED {
+            return Err(ConnectError::other("could not create Windows MM MIDI output port (MMSYSERR_ALLOCATED)", self));
+        } else if result != MMSYSERR_NOERROR {
+            return Err(ConnectError::other("could not create Windows MM MIDI output port", self));
+        }
+        Ok(MidiOutputConnection {
+            out_handle: unsafe { out_handle.assume_init() },
+        })
+    }
+}
+
+impl MidiOutputConnection {
+    pub fn close(self) -> MidiOutput {
+        // The actual closing is done by the implementation of Drop
+        MidiOutput // In this API this is a noop
+    }
+    
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {
+        let nbytes = message.len();
+        if nbytes == 0 {
+            return Err(SendError::InvalidData("message to be sent must not be empty"));
+        }
+        
+        if message[0] == 0xF0 { // Sysex message
+            // Allocate buffer for sysex data and copy message
+            let mut buffer = message.to_vec();
+        
+            // Create and prepare MIDIHDR structure.
+            let mut sysex = MIDIHDR {
+                lpData: buffer.as_mut_ptr() as *mut i8,
+                dwBufferLength: nbytes as u32,
+                dwBytesRecorded: 0,
+                dwUser: 0,
+                dwFlags: 0,
+                lpNext: ptr::null_mut(),
+                reserved: 0,
+                dwOffset: 0,
+                dwReserved: unsafe { mem::zeroed() },
+            };
+            
+            let result = unsafe { midiOutPrepareHeader(self.out_handle, &mut sysex, mem::size_of::<MIDIHDR>() as u32) };
+            
+            if result != MMSYSERR_NOERROR {
+                return Err(SendError::Other("preparation for sending sysex message failed (OutPrepareHeader)"));
+            }
+            
+            // Send the message.
+            loop {
+                let result = unsafe { midiOutLongMsg(self.out_handle, &mut sysex, mem::size_of::<MIDIHDR>() as u32) };
+                if result == MIDIERR_NOTREADY {
+                    sleep(Duration::from_millis(1));
+                    continue;
+                } else {
+                    if result != MMSYSERR_NOERROR {
+                        return Err(SendError::Other("sending sysex message failed"));
+                    }
+                    break;
+                }
+            }
+            
+            loop {
+                let result = unsafe { midiOutUnprepareHeader(self.out_handle, &mut sysex, mem::size_of::<MIDIHDR>() as u32) };
+                if result == MIDIERR_STILLPLAYING {
+                    sleep(Duration::from_millis(1));
+                    continue;
+                } else { break; }
+            }
+        } else { // Channel or system message.
+            // Make sure the message size isn't too big.
+            if nbytes > 3 {
+                return Err(SendError::InvalidData("non-sysex message must not be longer than 3 bytes"));
+            }
+            
+            // Pack MIDI bytes into double word.
+            let packet: DWORD = 0;
+            let ptr = &packet as *const u32 as *mut u8;
+            for i in 0..nbytes {
+                unsafe { *ptr.offset(i as isize) = message[i] };
+            }
+            
+            // Send the message immediately.
+            loop {
+                let result = unsafe { midiOutShortMsg(self.out_handle, packet) };
+                if result == MIDIERR_NOTREADY {
+                    sleep(Duration::from_millis(1));
+                    continue;
+                } else {
+                    if result != MMSYSERR_NOERROR {
+                        return Err(SendError::Other("sending non-sysex message failed"));
+                    }
+                    break;
+                }
+            }
+        }
+        
+        Ok(())
+    }
+}
+
+impl Drop for MidiOutputConnection {
+    fn drop(&mut self) {
+        unsafe {
+            midiOutReset(self.out_handle);
+            midiOutClose(self.out_handle);
+        }
+    }
+}
diff --git a/third_party/rust/midir/src/backend/winrt/mod.rs b/third_party/rust/midir/src/backend/winrt/mod.rs
new file mode 100644
index 0000000000..a8204ec742
--- /dev/null
+++ b/third_party/rust/midir/src/backend/winrt/mod.rs
@@ -0,0 +1,299 @@
+extern crate winrt;
+
+use std::sync::{Arc, Mutex};
+
+use ::errors::*;
+use ::Ignore;
+
+use self::winrt::{AbiTransferable, HString, TryInto};
+
+winrt::import!(
+    dependencies
+        os
+    types
+        windows::foundation::*
+        windows::devices::midi::*
+        windows::devices::enumeration::DeviceInformation
+        windows::storage::streams::{Buffer, DataWriter}
+);
+
+use self::windows::foundation::*;
+use self::windows::devices::midi::*;
+use self::windows::devices::enumeration::DeviceInformation;
+use self::windows::storage::streams::{Buffer, DataWriter};
+
+#[derive(Clone, PartialEq)]
+pub struct MidiInputPort {
+    id: HString
+}
+
+unsafe impl Send for MidiInputPort {} // because HString doesn't ...
+
+pub struct MidiInput {
+    selector: HString,
+    ignore_flags: Ignore
+}
+
+#[repr(C)]
+pub struct abi_IMemoryBufferByteAccess {
+    __base: [usize; 3],
+    get_buffer: extern "system" fn(
+        winrt::NonNullRawComPtr<IMemoryBufferByteAccess>,
+        value: *mut *mut u8,
+        capacity: *mut u32,
+    ) -> winrt::ErrorCode,
+}
+
+unsafe impl winrt::ComInterface for IMemoryBufferByteAccess {
+    type VTable = abi_IMemoryBufferByteAccess;
+    fn iid() -> winrt::Guid {
+      winrt::Guid::from_values(0x5b0d3235, 0x4dba, 0x4d44, [0x86, 0x5e, 0x8f, 0x1d, 0x0e, 0x4f, 0xd0, 0x4d])
+    }
+}
+
+unsafe impl AbiTransferable for IMemoryBufferByteAccess {
+    type Abi = winrt::RawComPtr<Self>;
+
+    fn get_abi(&self) -> Self::Abi {
+        self.ptr.get_abi()
+    }
+
+    fn set_abi(&mut self) -> *mut Self::Abi {
+        self.ptr.set_abi()
+    }
+}
+
+#[repr(transparent)]
+#[derive(Default, Clone)]
+pub struct IMemoryBufferByteAccess {
+    ptr: winrt::ComPtr<IMemoryBufferByteAccess>,
+}
+
+impl IMemoryBufferByteAccess {
+    pub unsafe fn get_buffer(&self) -> winrt::Result<&[u8]> {
+        match self.get_abi() {
+            None => panic!("The `this` pointer was null when calling method"),
+            Some(ptr) => {
+                let mut bufptr = std::ptr::null_mut();
+                let mut capacity: u32 = 0;
+                (ptr.vtable().get_buffer)(ptr, &mut bufptr, &mut capacity).ok()?;
+                if capacity == 0 {
+                    bufptr = 1 as *mut u8; // null pointer is not allowed
+                }
+                Ok(std::slice::from_raw_parts(bufptr, capacity as usize))
+            }
+        }
+    }
+}
+
+
+unsafe impl Send for MidiInput {} // because HString doesn't ...
+
+impl MidiInput {
+    pub fn new(_client_name: &str) -> Result<Self, InitError> {
+        let device_selector = MidiInPort::get_device_selector().map_err(|_| InitError)?;
+        Ok(MidiInput { selector: device_selector, ignore_flags: Ignore::None })
+    }
+
+    pub fn ignore(&mut self, flags: Ignore) {
+        self.ignore_flags = flags;
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiInputPort> {
+        let device_collection = DeviceInformation::find_all_async_aqs_filter(&self.selector).unwrap().get().expect("find_all_async failed");
+        let count = device_collection.size().expect("get_size failed") as usize;
+        let mut result = Vec::with_capacity(count as usize);
+        for device_info in device_collection.into_iter() {
+            let device_id = device_info.id().expect("get_id failed");
+            result.push(::common::MidiInputPort {
+                imp: MidiInputPort { id: device_id }
+            });
+        }
+        result
+    }
+    
+    pub fn port_count(&self) -> usize {
+        let device_collection = DeviceInformation::find_all_async_aqs_filter(&self.selector).unwrap().get().expect("find_all_async failed");
+        device_collection.size().expect("get_size failed") as usize
+    }
+    
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        let device_info_async = DeviceInformation::create_from_id_async(&port.id).map_err(|_| PortInfoError::InvalidPort)?;
+        let device_info = device_info_async.get().map_err(|_| PortInfoError::InvalidPort)?;
+        let device_name = device_info.name().map_err(|_| PortInfoError::CannotRetrievePortName)?;
+        Ok(device_name.to_string())
+    }
+
+    fn handle_input<T>(args: &MidiMessageReceivedEventArgs, handler_data: &mut HandlerData<T>) {
+        let ignore = handler_data.ignore_flags;
+        let data = &mut handler_data.user_data.as_mut().unwrap();
+        let timestamp;
+        let byte_access: IMemoryBufferByteAccess;
+        let message_bytes;
+        let message = args.message().expect("get_message failed");
+        timestamp = message.timestamp().expect("get_timestamp failed").duration as u64 / 10;
+        let buffer = message.raw_data().expect("get_raw_data failed");
+        let membuffer = Buffer::create_memory_buffer_over_ibuffer(&buffer).expect("create_memory_buffer_over_ibuffer failed");
+        byte_access = membuffer.create_reference().expect("create_reference failed").try_into().unwrap();
+        message_bytes = unsafe { byte_access.get_buffer().expect("get_buffer failed") }; // TODO: somehow make sure that the buffer is not invalidated while we're reading from it ...
+
+        // The first byte in the message is the status
+        let status = message_bytes[0];
+
+        if !(status == 0xF0 && ignore.contains(Ignore::Sysex) ||
+             status == 0xF1 && ignore.contains(Ignore::Time) ||
+             status == 0xF8 && ignore.contains(Ignore::Time) ||
+             status == 0xFE && ignore.contains(Ignore::ActiveSense))
+        {
+            (handler_data.callback)(timestamp, message_bytes, data);
+        }
+    }
+
+    pub fn connect<F, T: Send + 'static>(
+        self, port: &MidiInputPort, _port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        
+        let in_port = match MidiInPort::from_id_async(&port.id) {
+            Ok(port_async) => match port_async.get() {
+                Ok(port) => port,
+                _ => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+            }
+            Err(_) => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+        };
+        
+        let handler_data = Arc::new(Mutex::new(HandlerData {
+            ignore_flags: self.ignore_flags,
+            callback: Box::new(callback),
+            user_data: Some(data)
+        }));
+        let handler_data2 = handler_data.clone();
+
+        let handler = TypedEventHandler::new(move |_sender, args| {
+            MidiInput::handle_input(args, &mut *handler_data2.lock().unwrap());
+            Ok(())
+        });
+        
+        let event_token = in_port.message_received(&handler).expect("add_message_received failed");
+
+        Ok(MidiInputConnection { port: RtMidiInPort(in_port), event_token: event_token, handler_data: handler_data })
+    }
+}
+
+struct RtMidiInPort(MidiInPort);
+unsafe impl Send for RtMidiInPort {}
+
+pub struct MidiInputConnection<T> {
+    port: RtMidiInPort,
+    event_token: EventRegistrationToken,
+    // TODO: get rid of Arc & Mutex?
+    //       synchronization is required because the borrow checker does not
+    //       know that the callback we're in here is never called concurrently
+    //       (always in sequence)
+    handler_data: Arc<Mutex<HandlerData<T>>>
+}
+
+
+impl<T> MidiInputConnection<T> {
+    pub fn close(self) -> (MidiInput, T) {
+        let _ = self.port.0.remove_message_received(self.event_token);
+        let closable: IClosable = self.port.0.try_into().unwrap();
+        let _ = closable.close();
+        let device_selector = MidiInPort::get_device_selector().expect("get_device_selector failed"); // probably won't ever fail here, because it worked previously
+        let mut handler_data_locked = self.handler_data.lock().unwrap();
+        (MidiInput {
+            selector: device_selector,
+            ignore_flags: handler_data_locked.ignore_flags
+        }, handler_data_locked.user_data.take().unwrap())
+    }
+}
+
+/// This is all the data that is stored on the heap as long as a connection
+/// is opened and passed to the callback handler.
+///
+/// It is important that `user_data` is the last field to not influence
+/// offsets after monomorphization.
+struct HandlerData<T> {
+    ignore_flags: Ignore,
+    callback: Box<dyn FnMut(u64, &[u8], &mut T) + Send>,
+    user_data: Option<T>
+}
+
+#[derive(Clone, PartialEq)]
+pub struct MidiOutputPort {
+    id: HString
+}
+
+unsafe impl Send for MidiOutputPort {} // because HString doesn't ...
+
+pub struct MidiOutput {
+    selector: HString // TODO: change to FastHString?
+}
+
+unsafe impl Send for MidiOutput {} // because HString doesn't ...
+
+impl MidiOutput {
+    pub fn new(_client_name: &str) -> Result<Self, InitError> {
+        let device_selector = MidiOutPort::get_device_selector().map_err(|_| InitError)?;
+        Ok(MidiOutput { selector: device_selector })
+    }
+
+    pub(crate) fn ports_internal(&self) -> Vec<::common::MidiOutputPort> {
+        let device_collection = DeviceInformation::find_all_async_aqs_filter(&self.selector).unwrap().get().expect("find_all_async failed");
+        let count = device_collection.size().expect("get_size failed") as usize;
+        let mut result = Vec::with_capacity(count as usize);
+        for device_info in device_collection.into_iter() {
+            let device_id = device_info.id().expect("get_id failed");
+            result.push(::common::MidiOutputPort {
+                imp: MidiOutputPort { id: device_id }
+            });
+        }
+        result
+    }
+    
+    pub fn port_count(&self) -> usize {
+        let device_collection = DeviceInformation::find_all_async_aqs_filter(&self.selector).unwrap().get().expect("find_all_async failed");
+        device_collection.size().expect("get_size failed") as usize
+    }
+    
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        let device_info_async = DeviceInformation::create_from_id_async(&port.id).map_err(|_| PortInfoError::InvalidPort)?;
+        let device_info = device_info_async.get().map_err(|_| PortInfoError::InvalidPort)?;
+        let device_name = device_info.name().map_err(|_| PortInfoError::CannotRetrievePortName)?;
+        Ok(device_name.to_string())
+    }
+    
+    pub fn connect(self, port: &MidiOutputPort, _port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {        
+        let out_port = match MidiOutPort::from_id_async(&port.id) {
+            Ok(port_async) => match port_async.get() {
+                Ok(port) => port,
+                _ => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+            }
+            Err(_) => return Err(ConnectError::new(ConnectErrorKind::InvalidPort, self))
+        };
+        Ok(MidiOutputConnection { port: out_port })
+    }
+}
+
+pub struct MidiOutputConnection {
+    port: IMidiOutPort
+}
+
+unsafe impl Send for MidiOutputConnection {}
+
+impl MidiOutputConnection {
+    pub fn close(self) -> MidiOutput {
+        let closable: IClosable = self.port.try_into().unwrap();
+        let _ = closable.close();
+        let device_selector = MidiOutPort::get_device_selector().expect("get_device_selector failed"); // probably won't ever fail here, because it worked previously
+        MidiOutput { selector: device_selector }
+    }
+    
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {
+        let data_writer = DataWriter::new().unwrap();
+        data_writer.write_bytes(message).map_err(|_| SendError::Other("write_bytes failed"))?;
+        let buffer = data_writer.detach_buffer().map_err(|_| SendError::Other("detach_buffer failed"))?;
+        self.port.send_buffer(&buffer).map_err(|_| SendError::Other("send_buffer failed"))?;
+        Ok(())
+    }
+}
diff --git a/third_party/rust/midir/src/common.rs b/third_party/rust/midir/src/common.rs
new file mode 100644
index 0000000000..aed696b60c
--- /dev/null
+++ b/third_party/rust/midir/src/common.rs
@@ -0,0 +1,315 @@
+#![deny(missing_docs)]
+
+use ::errors::*;
+use ::backend::{
+    MidiInputPort as MidiInputPortImpl,
+    MidiInput as MidiInputImpl, 
+    MidiInputConnection as MidiInputConnectionImpl,
+    MidiOutputPort as MidiOutputPortImpl,
+    MidiOutput as MidiOutputImpl,
+    MidiOutputConnection as MidiOutputConnectionImpl
+};
+use ::Ignore;
+
+/// Trait that abstracts over input and output ports.
+pub trait MidiIO {
+    /// Type of an input or output port structure.
+    type Port: Clone;
+
+    /// Get a collection of all MIDI input or output ports.
+    /// The resulting vector contains one object per port, which you can use to
+    /// query metadata about the port or connect to it.
+    fn ports(&self) -> Vec<Self::Port>;
+    
+    /// Get the number of available MIDI input or output ports.
+    fn port_count(&self) -> usize;
+    
+    /// Get the name of a specified MIDI input or output port.
+    ///
+    /// An error will be returned when the port is no longer valid
+    /// (e.g. the respective device has been disconnected).
+    fn port_name(&self, port: &Self::Port) -> Result<String, PortInfoError>;
+}
+
+/// An object representing a single input port.
+/// How the port is identified internally is backend-dependent.
+/// If the backend allows it, port objects remain valid when
+/// other ports in the system change (i.e. it is not just an index).
+///
+/// Use the `ports` method of a `MidiInput` instance to obtain
+/// available ports.
+#[derive(Clone, PartialEq)]
+pub struct MidiInputPort {
+    pub(crate) imp: MidiInputPortImpl
+}
+
+/// A collection of input ports.
+pub type MidiInputPorts = Vec<MidiInputPort>;
+
+/// An instance of `MidiInput` is required for anything related to MIDI input.
+/// Create one with `MidiInput::new`.
+pub struct MidiInput {
+    //ignore_flags: Ignore
+    imp: MidiInputImpl
+}
+
+impl MidiInput {
+    /// Creates a new `MidiInput` object that is required for any MIDI input functionality.
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        MidiInputImpl::new(client_name).map(|imp| MidiInput { imp: imp })
+    }
+    
+    /// Set flags to decide what kind of messages should be ignored (i.e., filtered out)
+    /// by this `MidiInput`. By default, no messages are ignored.
+    pub fn ignore(&mut self, flags: Ignore) {
+       self.imp.ignore(flags);
+    }
+
+    /// Get a collection of all MIDI input ports that *midir* can connect to.
+    /// The resulting vector contains one object per port, which you can use to
+    /// query metadata about the port or connect to it in order to receive
+    /// MIDI messages.
+    pub fn ports(&self) -> MidiInputPorts {
+        self.imp.ports_internal()
+    }
+    
+    /// Get the number of available MIDI input ports that *midir* can connect to.
+    pub fn port_count(&self) -> usize {
+        self.imp.port_count()
+    }
+    
+    /// Get the name of a specified MIDI input port.
+    ///
+    /// An error will be returned when the port is no longer valid
+    /// (e.g. the respective device has been disconnected).
+    pub fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        self.imp.port_name(&port.imp)
+    }
+    
+    /// Connect to a specified MIDI input port in order to receive messages.
+    /// For each incoming MIDI message, the provided `callback` function will
+    /// be called. The first parameter of the callback function is a timestamp
+    /// (in microseconds) designating the time since some unspecified point in
+    /// the past (which will not change during the lifetime of a
+    /// `MidiInputConnection`). The second parameter contains the actual bytes
+    /// of the MIDI message.
+    ///
+    /// Additional data that should be passed whenever the callback is
+    /// invoked can be specified by `data`. Use the empty tuple `()` if
+    /// you do not want to pass any additional data.
+    ///
+    /// The connection will be kept open as long as the returned
+    /// `MidiInputConnection` is kept alive.
+    ///
+    /// The `port_name` is an additional name that will be assigned to the
+    /// connection. It is only used by some backends.
+    ///
+    /// An error will be returned when the port is no longer valid
+    /// (e.g. the respective device has been disconnected).
+    pub fn connect<F, T: Send>(
+        self, port: &MidiInputPort, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<MidiInput>>
+        where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        match self.imp.connect(&port.imp, port_name, callback, data) {
+            Ok(imp) => Ok(MidiInputConnection { imp: imp }),
+            Err(imp) => {
+                let kind = imp.kind();
+                Err(ConnectError::new(kind, MidiInput { imp: imp.into_inner() }))
+            } 
+        }
+    }
+}
+
+impl MidiIO for MidiInput {
+    type Port = MidiInputPort;
+
+    fn ports(&self) -> MidiInputPorts {
+        self.imp.ports_internal()
+    }
+
+    fn port_count(&self) -> usize {
+        self.imp.port_count()
+    }
+
+    fn port_name(&self, port: &MidiInputPort) -> Result<String, PortInfoError> {
+        self.imp.port_name(&port.imp)
+    }
+}
+
+#[cfg(unix)]
+impl<T: Send> ::os::unix::VirtualInput<T> for MidiInput {
+    fn create_virtual<F>(
+        self, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<Self>>
+    where F: FnMut(u64, &[u8], &mut T) + Send + 'static {
+        match self.imp.create_virtual(port_name, callback, data) {
+            Ok(imp) => Ok(MidiInputConnection { imp: imp }),
+            Err(imp) => {
+                let kind = imp.kind();
+                Err(ConnectError::new(kind, MidiInput { imp: imp.into_inner() }))
+            } 
+        }
+    }
+}
+
+/// Represents an open connection to a MIDI input port.
+pub struct MidiInputConnection<T: 'static> {
+    imp: MidiInputConnectionImpl<T>
+}
+
+impl<T> MidiInputConnection<T> {
+    /// Closes the connection. The returned values allow you to
+    /// inspect the additional data passed to the callback (the `data`
+    /// parameter of `connect`), or to reuse the `MidiInput` object,
+    /// but they can be safely ignored.
+    pub fn close(self) -> (MidiInput, T) {
+        let (imp, data) = self.imp.close();
+        (MidiInput { imp: imp }, data)
+    }
+}
+
+/// An object representing a single output port.
+/// How the port is identified internally is backend-dependent.
+/// If the backend allows it, port objects remain valid when
+/// other ports in the system change (i.e. it is not just an index).
+///
+/// Use the `ports` method of a `MidiOutput` instance to obtain
+/// available ports.
+#[derive(Clone, PartialEq)]
+pub struct MidiOutputPort {
+    pub(crate) imp: MidiOutputPortImpl
+}
+
+/// A collection of output ports.
+pub type MidiOutputPorts = Vec<MidiOutputPort>;
+
+/// An instance of `MidiOutput` is required for anything related to MIDI output.
+/// Create one with `MidiOutput::new`.
+pub struct MidiOutput {
+    imp: MidiOutputImpl
+}
+
+impl MidiOutput {
+    /// Creates a new `MidiOutput` object that is required for any MIDI output functionality.
+    pub fn new(client_name: &str) -> Result<Self, InitError> {
+        MidiOutputImpl::new(client_name).map(|imp| MidiOutput { imp: imp })
+    }
+
+    /// Get a collection of all MIDI output ports that *midir* can connect to.
+    /// The resulting vector contains one object per port, which you can use to
+    /// query metadata about the port or connect to it in order to send
+    /// MIDI messages.
+    pub fn ports(&self) -> MidiOutputPorts {
+        self.imp.ports_internal()
+    }
+    
+    /// Get the number of available MIDI output ports that *midir* can connect to.
+    pub fn port_count(&self) -> usize {
+        self.imp.port_count()
+    }
+    
+    /// Get the name of a specified MIDI output port.
+    ///
+    /// An error will be returned when the port is no longer valid
+    /// (e.g. the respective device has been disconnected).
+    pub fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        self.imp.port_name(&port.imp)
+    }
+    
+    /// Connect to a specified MIDI output port in order to send messages.
+    /// The connection will be kept open as long as the returned
+    /// `MidiOutputConnection` is kept alive.
+    ///
+    /// The `port_name` is an additional name that will be assigned to the
+    /// connection. It is only used by some backends.
+    ///
+    /// An error will be returned when the port is no longer valid
+    /// (e.g. the respective device has been disconnected).
+    pub fn connect(self, port: &MidiOutputPort, port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        match self.imp.connect(&port.imp, port_name) {
+            Ok(imp) => Ok(MidiOutputConnection { imp: imp }),
+            Err(imp) => {
+                let kind = imp.kind();
+                Err(ConnectError::new(kind, MidiOutput { imp: imp.into_inner() }))
+            } 
+        }
+    }
+}
+
+impl MidiIO for MidiOutput {
+    type Port = MidiOutputPort;
+
+    fn ports(&self) -> MidiOutputPorts {
+        self.imp.ports_internal()
+    }
+
+    fn port_count(&self) -> usize {
+        self.imp.port_count()
+    }
+
+    fn port_name(&self, port: &MidiOutputPort) -> Result<String, PortInfoError> {
+        self.imp.port_name(&port.imp)
+    }
+}
+
+#[cfg(unix)]
+impl ::os::unix::VirtualOutput for MidiOutput {
+    fn create_virtual(self, port_name: &str) -> Result<MidiOutputConnection, ConnectError<MidiOutput>> {
+        match self.imp.create_virtual(port_name) {
+            Ok(imp) => Ok(MidiOutputConnection { imp: imp }),
+            Err(imp) => {
+                let kind = imp.kind();
+                Err(ConnectError::new(kind, MidiOutput { imp: imp.into_inner() }))
+            } 
+        }
+    }
+}
+
+/// Represents an open connection to a MIDI output port.
+pub struct MidiOutputConnection {
+   imp: MidiOutputConnectionImpl
+}
+
+impl MidiOutputConnection {
+    /// Closes the connection. The returned value allows you to
+    /// reuse the `MidiOutput` object, but it can be safely ignored.
+    pub fn close(self) -> MidiOutput {
+        MidiOutput { imp: self.imp.close() }
+    }
+    
+    /// Send a message to the port that this output connection is connected to.
+    /// The message must be a valid MIDI message (see https://www.midi.org/specifications-old/item/table-1-summary-of-midi-message).
+    pub fn send(&mut self, message: &[u8]) -> Result<(), SendError> {
+        self.imp.send(message)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_trait_impls() {
+        // make sure that all the structs implement `Send`
+        fn is_send<T: Send>() {}
+        is_send::<MidiInput>();
+        is_send::<MidiOutput>();
+        #[cfg(not(target_arch = "wasm32"))] {
+            // The story around threading and `Send` on WASM is not clear yet
+            // Tracking issue:      https://github.com/Boddlnagg/midir/issues/49
+            // Prev. discussion:    https://github.com/Boddlnagg/midir/pull/47
+            is_send::<MidiInputPort>();
+            is_send::<MidiInputConnection<()>>();
+            is_send::<MidiOutputPort>();
+            is_send::<MidiOutputConnection>();
+        }
+
+        // make sure that Midi port structs implement `PartialEq`
+        fn is_partial_eq<T: PartialEq>() {}
+        is_partial_eq::<MidiInputPortImpl>();
+        is_partial_eq::<MidiOutputPortImpl>();
+
+        is_partial_eq::<MidiInputPort>();
+        is_partial_eq::<MidiOutputPort>();
+    }
+}
diff --git a/third_party/rust/midir/src/errors.rs b/third_party/rust/midir/src/errors.rs
new file mode 100644
index 0000000000..69331528c9
--- /dev/null
+++ b/third_party/rust/midir/src/errors.rs
@@ -0,0 +1,114 @@
+use std::error::Error;
+use std::fmt;
+
+const INVALID_PORT_MSG: &str = "invalid port";
+const PORT_OUT_OF_RANGE_MSG: &str = "provided port number was out of range";
+const CANNOT_RETRIEVE_PORT_NAME_MSG: &str = "unknown error when trying to retrieve the port name";
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// An error that can occur during initialization (i.e., while
+/// creating a `MidiInput` or `MidiOutput` object).
+pub struct InitError;
+
+impl Error for InitError {}
+
+impl fmt::Display for InitError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        "MIDI support could not be initialized".fmt(f)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// An error that can occur when retrieving information about
+/// available ports.
+pub enum PortInfoError {
+    PortNumberOutOfRange, // TODO: don't expose this
+    InvalidPort,
+    CannotRetrievePortName,
+}
+
+impl Error for PortInfoError {}
+
+impl fmt::Display for PortInfoError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            PortInfoError::PortNumberOutOfRange => PORT_OUT_OF_RANGE_MSG.fmt(f),
+            PortInfoError::InvalidPort => INVALID_PORT_MSG.fmt(f),
+            PortInfoError::CannotRetrievePortName => CANNOT_RETRIEVE_PORT_NAME_MSG.fmt(f),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// The kind of error for a `ConnectError`.
+pub enum ConnectErrorKind {
+    InvalidPort,
+    Other(&'static str)
+}
+
+impl ConnectErrorKind {}
+
+impl fmt::Display for ConnectErrorKind {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            ConnectErrorKind::InvalidPort => INVALID_PORT_MSG.fmt(f),
+            ConnectErrorKind::Other(msg) => msg.fmt(f)
+        }
+    }
+}
+
+/// An error that can occur when trying to connect to a port.
+pub struct ConnectError<T> {
+    kind: ConnectErrorKind,
+    inner: T
+}
+
+impl<T> ConnectError<T> {
+    pub fn new(kind: ConnectErrorKind, inner: T) -> ConnectError<T> {
+        ConnectError { kind: kind, inner: inner }
+    }
+    
+    /// Helper method to create ConnectErrorKind::Other.
+    pub fn other(msg: &'static str, inner: T) -> ConnectError<T> {
+        Self::new(ConnectErrorKind::Other(msg), inner)
+    }
+    
+    pub fn kind(&self) -> ConnectErrorKind {
+        self.kind
+    }
+    
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+impl<T> fmt::Debug for ConnectError<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        self.kind.fmt(f)
+    }
+}
+
+impl<T> fmt::Display for ConnectError<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.kind.fmt(f)
+    }
+}
+
+impl<T> Error for ConnectError<T> {}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// An error that can occur when sending MIDI messages.
+pub enum SendError {
+    InvalidData(&'static str),
+    Other(&'static str)
+}
+
+impl Error for SendError {}
+
+impl fmt::Display for SendError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            SendError::InvalidData(msg) | SendError::Other(msg) => msg.fmt(f)
+        }
+    }
+}
diff --git a/third_party/rust/midir/src/lib.rs b/third_party/rust/midir/src/lib.rs
new file mode 100644
index 0000000000..99d6840c33
--- /dev/null
+++ b/third_party/rust/midir/src/lib.rs
@@ -0,0 +1,65 @@
+extern crate memalloc;
+
+#[cfg(feature = "jack")]
+#[macro_use] extern crate bitflags;
+
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// An enum that is used to specify what kind of MIDI messages should
+/// be ignored when receiving messages.
+pub enum Ignore {
+    None = 0x00,
+    Sysex = 0x01,
+    Time = 0x02,
+    SysexAndTime = 0x03,
+    ActiveSense = 0x04,
+    SysexAndActiveSense = 0x05,
+    TimeAndActiveSense = 0x06,
+    All = 0x07
+}
+
+impl std::ops::BitOr for Ignore {
+    type Output = Ignore;
+    #[inline(always)]
+    fn bitor(self, rhs: Self) -> Self::Output {
+        // this is safe because all combinations also exist as variants
+        unsafe { std::mem::transmute(self as u8 | rhs as u8) }
+    }
+}
+
+impl Ignore {
+    #[inline(always)]
+    pub fn contains(self, other: Ignore) -> bool {
+        self as u8 & other as u8 != 0 
+    }
+}
+
+/// A MIDI structure used internally by some backends to store incoming
+/// messages. Each message represents one and only one MIDI message.
+/// The timestamp is represented as the elapsed microseconds since
+/// a point in time that is arbitrary, but does not change for the
+/// lifetime of a given MidiInputConnection.
+#[derive(Debug, Clone)]
+struct MidiMessage {
+    bytes: Vec<u8>,
+    timestamp: u64
+}
+
+impl MidiMessage {
+    fn new() -> MidiMessage {
+        MidiMessage {
+            bytes: vec![],
+            timestamp: 0
+        }
+    }
+}
+
+pub mod os; // include platform-specific behaviour
+
+mod errors;
+pub use errors::*;
+
+mod common;
+pub use common::*;
+
+mod backend;
\ No newline at end of file
diff --git a/third_party/rust/midir/src/os/mod.rs b/third_party/rust/midir/src/os/mod.rs
new file mode 100644
index 0000000000..70ff75cd9d
--- /dev/null
+++ b/third_party/rust/midir/src/os/mod.rs
@@ -0,0 +1 @@
+#[cfg(unix)] pub mod unix;
\ No newline at end of file
diff --git a/third_party/rust/midir/src/os/unix.rs b/third_party/rust/midir/src/os/unix.rs
new file mode 100644
index 0000000000..88dcfee1d9
--- /dev/null
+++ b/third_party/rust/midir/src/os/unix.rs
@@ -0,0 +1,27 @@
+use ::ConnectError;
+use ::{MidiInputConnection, MidiOutputConnection};
+
+// TODO: maybe move to module `virtual` instead of `os::unix`?
+
+/// Trait that is implemented by `MidiInput` on platforms that
+/// support virtual ports (currently every platform but Windows).
+pub trait VirtualInput<T: Send> where Self: Sized {
+    /// Creates a virtual input port. Once it has been created,
+    /// other applications can connect to this port and send MIDI
+    /// messages which will be received by this port.
+    fn create_virtual<F>(
+        self, port_name: &str, callback: F, data: T
+    ) -> Result<MidiInputConnection<T>, ConnectError<Self>>
+    where F: FnMut(u64, &[u8], &mut T) + Send + 'static;
+}
+
+/// Trait that is implemented by `MidiOutput` on platforms that
+/// support virtual ports (currently every platform but Windows).
+pub trait VirtualOutput where Self: Sized {
+    /// Creates a virtual output port. Once it has been created,
+    /// other applications can connect to this port and will
+    /// receive MIDI messages that are sent to this port.
+    fn create_virtual(
+        self, port_name: &str
+    ) -> Result<MidiOutputConnection, ConnectError<Self>>;
+}
\ No newline at end of file