protoflow_core/
input_port.rs

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// This is free and unencumbered software released into the public domain.

use crate::{
    prelude::{fmt, Arc, Cow, MaybeLabeled, MaybeNamed, PhantomData},
    InputPortID, Message, MessageReceiver, Port, PortID, PortResult, PortState, System, Transport,
};

#[derive(Clone)] //, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub struct InputPort<T: Message> {
    pub(crate) id: InputPortID,
    pub(crate) transport: Arc<dyn Transport>,
    _phantom: PhantomData<T>,
}

impl<T: Message> InputPort<T> {
    pub fn new<X: Transport + Default>(system: &System<X>) -> Self {
        let runtime = system.runtime.as_ref();
        let transport = runtime.transport.clone();
        Self {
            _phantom: PhantomData,
            id: transport.open_input().unwrap(),
            transport,
        }
    }

    pub fn close(&mut self) -> PortResult<bool> {
        self.transport.close(PortID::Input(self.id))
    }

    pub fn recv(&self) -> PortResult<Option<T>> {
        match self.transport.recv(self.id)? {
            None => Ok(None), // EOS (port closed)
            Some(encoded_message) => {
                if encoded_message.len() == 0 {
                    Ok(None) // EOS (port disconnected)
                } else {
                    match T::decode_length_delimited(encoded_message) {
                        Ok(message) => Ok(Some(message)),
                        Err(err) => Err(err.into()),
                    }
                }
            }
        }
    }

    pub fn try_recv(&self) -> PortResult<Option<T>> {
        match self.transport.try_recv(self.id)? {
            None => Ok(None), // EOS
            Some(encoded_message) => match T::decode(encoded_message) {
                Ok(message) => Ok(Some(message)),
                Err(err) => Err(err.into()),
            },
        }
    }
}

impl<T: Message> MaybeNamed for InputPort<T> {
    fn name(&self) -> Option<Cow<str>> {
        None // TODO
    }
}

impl<T: Message> MaybeLabeled for InputPort<T> {
    fn label(&self) -> Option<Cow<str>> {
        None // TODO
    }
}

impl<T: Message> Port for InputPort<T> {
    fn id(&self) -> PortID {
        PortID::Input(self.id)
    }

    fn state(&self) -> PortState {
        self.transport
            .state(PortID::Input(self.id))
            .unwrap_or(PortState::Closed)
    }

    fn close(&mut self) -> PortResult<bool> {
        InputPort::close(self)
    }
}

impl<T: Message> MessageReceiver<T> for InputPort<T> {
    fn recv(&self) -> PortResult<Option<T>> {
        InputPort::recv(self)
    }

    fn try_recv(&self) -> PortResult<Option<T>> {
        InputPort::try_recv(self)
    }
}

impl<T: Message> fmt::Display for InputPort<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "→{}", self.id)
    }
}

impl<T: Message> fmt::Debug for InputPort<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.debug_struct("InputPort").field("id", &self.id).finish()
    }
}