midir/

common.rs

#![deny(missing_docs)]

use backend::{
    MidiInput as MidiInputImpl, MidiInputConnection as MidiInputConnectionImpl,
    MidiInputPort as MidiInputPortImpl, MidiOutput as MidiOutputImpl,
    MidiOutputConnection as MidiOutputConnectionImpl, MidiOutputPort as MidiOutputPortImpl,
};
use errors::*;

use crate::{backend, errors, Ignore, InitError};

/// 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    /// An error will be returned when the port is no longer valid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,
}

impl MidiInputPort {
    /// Get a unique stable identifier for this port.
    /// This identifier must be treated as an opaque string.
    pub fn id(&self) -> String {
        self.imp.id()
    }
}

/// 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 })
    }

    /// 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)
    }

    /// Get a MIDI input port by its unique identifier.
    pub fn find_port_by_id(&self, id: String) -> Option<MidiInputPort> {
        self.ports().into_iter().find(|port| port.id() == id)
    }

    /// 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 }),
            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> crate::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 }),
            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 }, 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,
}

impl MidiOutputPort {
    /// Get a unique stable identifier for this port.
    /// This identifier must be treated as an opaque string.
    pub fn id(&self) -> String {
        self.imp.id()
    }
}

/// 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 })
    }

    /// 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)
    }

    /// Get a MIDI output port by its unique identifier.
    pub fn find_port_by_id(&self, id: String) -> Option<MidiOutputPort> {
        self.ports().into_iter().find(|port| port.id() == id)
    }

    /// 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 }),
            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 crate::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 }),
            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>();
    }
}