146 lines
4.5 KiB
Rust
146 lines
4.5 KiB
Rust
// Copyright (c) 2022 Marceline Cramer
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// SPDX-License-Identifier: AGPL-3.0-or-later
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use std::collections::VecDeque;
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use std::io::{Read, Write};
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use std::marker::PhantomData;
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use std::path::PathBuf;
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use serde::{de::DeserializeOwned, Deserialize, Serialize};
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/// The name of the Magpie server socket.
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pub const MAGPIE_SOCK: &str = "magpie.sock";
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/// An identifier for a Magpie panel.
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///
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/// Only valid on a connection between a single client and its server. Clients
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/// are allowed to use arbitrary values for [PanelId].
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pub type PanelId = u32;
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/// Creates a new Magpie panel with a given ID.
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///
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/// If the given [PanelId] is already being used on this connection, the server
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/// will delete the old panel using that [PanelId].
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#[derive(Clone, Debug, Deserialize, Serialize)]
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pub struct CreatePanel {
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pub id: PanelId,
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pub script: PathBuf,
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}
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/// Sends a panel a message.
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#[derive(Clone, Debug, Deserialize, Serialize)]
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pub struct SendMessage {
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pub id: PanelId,
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pub msg: Vec<u8>,
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}
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/// A message sent from a Magpie client to the server.
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#[derive(Clone, Debug, Deserialize, Serialize)]
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#[serde(tag = "kind")]
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pub enum MagpieServerMsg {
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CreatePanel(CreatePanel),
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SendMessage(SendMessage),
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}
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/// A message sent from the Magpie server to a client.
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#[derive(Clone, Debug, Deserialize, Serialize)]
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#[serde(tag = "kind")]
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pub enum MagpieClientMsg {}
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/// A [Messenger] specialized for Magpie clients.
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pub type ClientMessenger<T> = Messenger<T, MagpieClientMsg, MagpieServerMsg>;
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/// A [Messenger] specialized for Magpie servers.
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pub type ServerMessenger<T> = Messenger<T, MagpieServerMsg, MagpieClientMsg>;
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/// Bidirectional, transport-agnostic Magpie IO wrapper struct.
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pub struct Messenger<T, I, O> {
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pub transport: T,
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expected_len: Option<usize>,
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received_buf: VecDeque<u8>,
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received_queue: VecDeque<I>,
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closed: bool,
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_output: PhantomData<O>,
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}
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impl<T: Read + Write, I: DeserializeOwned, O: Serialize> Messenger<T, I, O> {
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pub fn new(transport: T) -> Self {
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Self {
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transport,
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expected_len: None,
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received_buf: Default::default(),
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received_queue: Default::default(),
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closed: false,
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_output: PhantomData,
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}
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}
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pub fn is_closed(&self) -> bool {
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self.closed
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}
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pub fn send(&mut self, msg: &O) -> std::io::Result<()> {
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use byteorder::{LittleEndian, WriteBytesExt};
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let payload = serde_json::to_vec(msg).unwrap();
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let len = payload.len() as u32;
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self.transport.write_u32::<LittleEndian>(len)?;
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self.transport.write_all(&payload)?;
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self.transport.flush()?;
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Ok(())
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}
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/// Receives all pending messages and queues them for [recv].
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pub fn flush_recv(&mut self) -> std::io::Result<()> {
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let mut buf = [0u8; 1024];
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loop {
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match self.transport.read(&mut buf) {
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Ok(0) => {
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self.closed = true;
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break;
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}
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Ok(n) => {
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self.received_buf.write(&buf[..n])?;
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}
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Err(ref err) if err.kind() == std::io::ErrorKind::WouldBlock => break,
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Err(ref err) if err.kind() == std::io::ErrorKind::Interrupted => continue,
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Err(err) => return Err(err),
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}
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}
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loop {
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if let Some(expected_len) = self.expected_len {
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if self.received_buf.len() < expected_len {
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break;
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}
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self.expected_len = None;
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let mut buf = vec![0u8; expected_len];
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self.received_buf.read_exact(&mut buf)?;
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match serde_json::from_slice::<I>(&buf) {
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Ok(received) => self.received_queue.push_front(received),
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Err(e) => {
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let kind = std::io::ErrorKind::InvalidData;
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let payload = Box::new(e);
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let error = std::io::Error::new(kind, payload);
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return Err(error);
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}
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}
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} else if self.received_buf.len() >= 4 {
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use byteorder::{LittleEndian, ReadBytesExt};
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let expected_len = self.received_buf.read_u32::<LittleEndian>()?;
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self.expected_len = Some(expected_len as usize);
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} else {
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break;
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}
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}
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Ok(())
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}
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/// Tries to receive a single input packet.
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pub fn recv(&mut self) -> Option<I> {
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self.received_queue.pop_back()
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}
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}
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