extract frontend crate (#186)

lan-mouse-ipc/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "lan-mouse-ipc"
+description = "library for communication between lan-mouse service and frontends"
+version = "0.1.0"
+edition = "2021"
+license = "GPL-3.0-or-later"
+repository = "https://github.com/feschber/lan-mouse"
+
+[dependencies]
+futures = "0.3.30"
+log = "0.4.22"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0.107"
+thiserror = "1.0.63"
+tokio = { version = "1.32.0", features = ["net", "io-util", "time"] }
+tokio-stream = { version = "0.1.15", features = ["io-util"] }

lan-mouse-ipc/src/connect.rs

@@ -0,0 +1,89 @@
+use crate::{ConnectionError, FrontendEvent, FrontendRequest, IpcError};
+use std::{
+    cmp::min,
+    io::{self, prelude::*, BufReader, LineWriter, Lines},
+    thread,
+    time::Duration,
+};
+
+#[cfg(unix)]
+use std::os::unix::net::UnixStream;
+
+#[cfg(windows)]
+use std::net::TcpStream;
+
+pub struct FrontendEventReader {
+    #[cfg(unix)]
+    lines: Lines<BufReader<UnixStream>>,
+    #[cfg(windows)]
+    lines: Lines<BufReader<TcpStream>>,
+}
+
+pub struct FrontendRequestWriter {
+    #[cfg(unix)]
+    line_writer: LineWriter<UnixStream>,
+    #[cfg(windows)]
+    line_writer: LineWriter<TcpStream>,
+}
+
+impl FrontendEventReader {
+    pub fn next_event(&mut self) -> Option<Result<FrontendEvent, IpcError>> {
+        match self.lines.next()? {
+            Err(e) => Some(Err(e.into())),
+            Ok(l) => Some(serde_json::from_str(l.as_str()).map_err(|e| e.into())),
+        }
+    }
+}
+
+impl FrontendRequestWriter {
+    pub fn request(&mut self, request: FrontendRequest) -> Result<(), io::Error> {
+        let mut json = serde_json::to_string(&request).unwrap();
+        log::debug!("requesting: {json}");
+        json.push('\n');
+        self.line_writer.write_all(json.as_bytes())?;
+        Ok(())
+    }
+}
+
+pub fn connect() -> Result<(FrontendEventReader, FrontendRequestWriter), ConnectionError> {
+    let rx = wait_for_service()?;
+    let tx = rx.try_clone()?;
+    let buf_reader = BufReader::new(rx);
+    let lines = buf_reader.lines();
+    let line_writer = LineWriter::new(tx);
+    let reader = FrontendEventReader { lines };
+    let writer = FrontendRequestWriter { line_writer };
+    Ok((reader, writer))
+}
+
+/// wait for the lan-mouse socket to come online
+#[cfg(unix)]
+fn wait_for_service() -> Result<UnixStream, ConnectionError> {
+    let socket_path = crate::default_socket_path()?;
+    let mut duration = Duration::from_millis(10);
+    loop {
+        if let Ok(stream) = UnixStream::connect(&socket_path) {
+            break Ok(stream);
+        }
+        // a signaling mechanism or inotify could be used to
+        // improve this
+        thread::sleep(exponential_back_off(&mut duration));
+    }
+}
+
+#[cfg(windows)]
+fn wait_for_service() -> Result<TcpStream, ConnectionError> {
+    let mut duration = Duration::from_millis(10);
+    loop {
+        if let Ok(stream) = TcpStream::connect("127.0.0.1:5252") {
+            break Ok(stream);
+        }
+        thread::sleep(exponential_back_off(&mut duration));
+    }
+}
+
+fn exponential_back_off(duration: &mut Duration) -> Duration {
+    let new = duration.saturating_mul(2);
+    *duration = min(new, Duration::from_secs(1));
+    *duration
+}

lan-mouse-ipc/src/connect_async.rs

@@ -0,0 +1,104 @@
+use crate::{ConnectionError, FrontendEvent, FrontendRequest, IpcError};
+use std::{
+    cmp::min,
+    io,
+    task::{ready, Poll},
+    time::Duration,
+};
+
+use futures::{Stream, StreamExt};
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader, ReadHalf, WriteHalf};
+use tokio_stream::wrappers::LinesStream;
+
+#[cfg(unix)]
+use tokio::net::UnixStream;
+
+#[cfg(windows)]
+use tokio::net::TcpStream;
+
+pub struct AsyncFrontendEventReader {
+    #[cfg(unix)]
+    lines_stream: LinesStream<BufReader<ReadHalf<UnixStream>>>,
+    #[cfg(windows)]
+    lines_stream: LinesStream<BufReader<ReadHalf<TcpStream>>>,
+}
+
+pub struct AsyncFrontendRequestWriter {
+    #[cfg(unix)]
+    tx: WriteHalf<UnixStream>,
+    #[cfg(windows)]
+    tx: WriteHalf<TcpStream>,
+}
+
+impl Stream for AsyncFrontendEventReader {
+    type Item = Result<FrontendEvent, IpcError>;
+
+    fn poll_next(
+        mut self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Option<Self::Item>> {
+        let line = ready!(self.lines_stream.poll_next_unpin(cx));
+        let event = line.map(|l| {
+            l.map_err(Into::<IpcError>::into)
+                .and_then(|l| serde_json::from_str(l.as_str()).map_err(|e| e.into()))
+        });
+        Poll::Ready(event)
+    }
+}
+
+impl AsyncFrontendRequestWriter {
+    pub async fn request(&mut self, request: FrontendRequest) -> Result<(), io::Error> {
+        let mut json = serde_json::to_string(&request).unwrap();
+        log::debug!("requesting: {json}");
+        json.push('\n');
+        self.tx.write_all(json.as_bytes()).await?;
+        Ok(())
+    }
+}
+
+pub async fn connect_async(
+) -> Result<(AsyncFrontendEventReader, AsyncFrontendRequestWriter), ConnectionError> {
+    let stream = wait_for_service().await?;
+    #[cfg(unix)]
+    let (rx, tx): (ReadHalf<UnixStream>, WriteHalf<UnixStream>) = tokio::io::split(stream);
+    #[cfg(windows)]
+    let (rx, tx): (ReadHalf<TcpStream>, WriteHalf<TcpStream>) = tokio::io::split(stream);
+    let buf_reader = BufReader::new(rx);
+    let lines = buf_reader.lines();
+    let lines_stream = LinesStream::new(lines);
+    let reader = AsyncFrontendEventReader { lines_stream };
+    let writer = AsyncFrontendRequestWriter { tx };
+    Ok((reader, writer))
+}
+
+/// wait for the lan-mouse socket to come online
+#[cfg(unix)]
+async fn wait_for_service() -> Result<UnixStream, ConnectionError> {
+    let socket_path = crate::default_socket_path()?;
+    let mut duration = Duration::from_millis(10);
+    loop {
+        if let Ok(stream) = UnixStream::connect(&socket_path).await {
+            break Ok(stream);
+        }
+        // a signaling mechanism or inotify could be used to
+        // improve this
+        tokio::time::sleep(exponential_back_off(&mut duration)).await;
+    }
+}
+
+#[cfg(windows)]
+async fn wait_for_service() -> Result<TcpStream, ConnectionError> {
+    let mut duration = Duration::from_millis(10);
+    loop {
+        if let Ok(stream) = TcpStream::connect("127.0.0.1:5252").await {
+            break Ok(stream);
+        }
+        tokio::time::sleep(exponential_back_off(&mut duration)).await;
+    }
+}
+
+fn exponential_back_off(duration: &mut Duration) -> Duration {
+    let new = duration.saturating_mul(2);
+    *duration = min(new, Duration::from_secs(1));
+    *duration
+}

lan-mouse-ipc/src/lib.rs

@@ -0,0 +1,262 @@
+use std::{
+    collections::HashSet,
+    env::VarError,
+    fmt::Display,
+    io,
+    net::{IpAddr, SocketAddr},
+    str::FromStr,
+};
+use thiserror::Error;
+
+#[cfg(unix)]
+use std::{
+    env,
+    path::{Path, PathBuf},
+};
+
+use serde::{Deserialize, Serialize};
+
+mod connect;
+mod connect_async;
+mod listen;
+
+pub use connect::{connect, FrontendEventReader, FrontendRequestWriter};
+pub use connect_async::{connect_async, AsyncFrontendEventReader, AsyncFrontendRequestWriter};
+pub use listen::AsyncFrontendListener;
+
+#[derive(Debug, Error)]
+pub enum ConnectionError {
+    #[error(transparent)]
+    SocketPath(#[from] SocketPathError),
+    #[error(transparent)]
+    Io(#[from] io::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum ListenerCreationError {
+    #[error("could not determine socket-path: `{0}`")]
+    SocketPath(#[from] SocketPathError),
+    #[error("service already running!")]
+    AlreadyRunning,
+    #[error("failed to bind lan-mouse socket: `{0}`")]
+    Bind(io::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum IpcError {
+    #[error("io error occured: `{0}`")]
+    Io(#[from] io::Error),
+    #[error("invalid json: `{0}`")]
+    Json(#[from] serde_json::Error),
+    #[error(transparent)]
+    Connection(#[from] ConnectionError),
+    #[error(transparent)]
+    Listen(#[from] ListenerCreationError),
+}
+
+pub const DEFAULT_PORT: u16 = 4242;
+
+#[derive(Debug, Default, Eq, Hash, PartialEq, Clone, Copy, Serialize, Deserialize)]
+pub enum Position {
+    #[default]
+    Left,
+    Right,
+    Top,
+    Bottom,
+}
+
+#[derive(Debug, Error)]
+#[error("not a valid position: {pos}")]
+pub struct PositionParseError {
+    pos: String,
+}
+
+impl FromStr for Position {
+    type Err = PositionParseError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "left" => Ok(Self::Left),
+            "right" => Ok(Self::Right),
+            "top" => Ok(Self::Top),
+            "bottom" => Ok(Self::Bottom),
+            _ => Err(PositionParseError { pos: s.into() }),
+        }
+    }
+}
+
+impl Display for Position {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                Position::Left => "left",
+                Position::Right => "right",
+                Position::Top => "top",
+                Position::Bottom => "bottom",
+            }
+        )
+    }
+}
+
+impl TryFrom<&str> for Position {
+    type Error = ();
+
+    fn try_from(s: &str) -> Result<Self, Self::Error> {
+        match s {
+            "left" => Ok(Position::Left),
+            "right" => Ok(Position::Right),
+            "top" => Ok(Position::Top),
+            "bottom" => Ok(Position::Bottom),
+            _ => Err(()),
+        }
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Serialize, Deserialize)]
+pub struct ClientConfig {
+    /// hostname of this client
+    pub hostname: Option<String>,
+    /// fix ips, determined by the user
+    pub fix_ips: Vec<IpAddr>,
+    /// both active_addr and addrs can be None / empty so port needs to be stored seperately
+    pub port: u16,
+    /// position of a client on screen
+    pub pos: Position,
+    /// enter hook
+    pub cmd: Option<String>,
+}
+
+impl Default for ClientConfig {
+    fn default() -> Self {
+        Self {
+            port: DEFAULT_PORT,
+            hostname: Default::default(),
+            fix_ips: Default::default(),
+            pos: Default::default(),
+            cmd: None,
+        }
+    }
+}
+
+pub type ClientHandle = u64;
+
+#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+pub struct ClientState {
+    /// events should be sent to and received from the client
+    pub active: bool,
+    /// `active` address of the client, used to send data to.
+    /// This should generally be the socket address where data
+    /// was last received from.
+    pub active_addr: Option<SocketAddr>,
+    /// tracks whether or not the client is responding to pings
+    pub alive: bool,
+    /// ips from dns
+    pub dns_ips: Vec<IpAddr>,
+    /// all ip addresses associated with a particular client
+    /// e.g. Laptops usually have at least an ethernet and a wifi port
+    /// which have different ip addresses
+    pub ips: HashSet<IpAddr>,
+    /// client has pressed keys
+    pub has_pressed_keys: bool,
+    /// dns resolving in progress
+    pub resolving: bool,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum FrontendEvent {
+    /// a client was created
+    Created(ClientHandle, ClientConfig, ClientState),
+    /// no such client
+    NoSuchClient(ClientHandle),
+    /// state changed
+    State(ClientHandle, ClientConfig, ClientState),
+    /// the client was deleted
+    Deleted(ClientHandle),
+    /// new port, reason of failure (if failed)
+    PortChanged(u16, Option<String>),
+    /// list of all clients, used for initial state synchronization
+    Enumerate(Vec<(ClientHandle, ClientConfig, ClientState)>),
+    /// an error occured
+    Error(String),
+    /// capture status
+    CaptureStatus(Status),
+    /// emulation status
+    EmulationStatus(Status),
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Serialize, Deserialize)]
+pub enum FrontendRequest {
+    /// activate/deactivate client
+    Activate(ClientHandle, bool),
+    /// add a new client
+    Create,
+    /// change the listen port (recreate udp listener)
+    ChangePort(u16),
+    /// remove a client
+    Delete(ClientHandle),
+    /// request an enumeration of all clients
+    Enumerate(),
+    /// resolve dns
+    ResolveDns(ClientHandle),
+    /// update hostname
+    UpdateHostname(ClientHandle, Option<String>),
+    /// update port
+    UpdatePort(ClientHandle, u16),
+    /// update position
+    UpdatePosition(ClientHandle, Position),
+    /// update fix-ips
+    UpdateFixIps(ClientHandle, Vec<IpAddr>),
+    /// request the state of the given client
+    GetState(ClientHandle),
+    /// request reenabling input capture
+    EnableCapture,
+    /// request reenabling input emulation
+    EnableEmulation,
+    /// synchronize all state
+    Sync,
+}
+
+#[derive(Clone, Copy, Debug, Default, Serialize, Deserialize)]
+pub enum Status {
+    #[default]
+    Disabled,
+    Enabled,
+}
+
+impl From<Status> for bool {
+    fn from(status: Status) -> Self {
+        match status {
+            Status::Enabled => true,
+            Status::Disabled => false,
+        }
+    }
+}
+
+#[cfg(unix)]
+const LAN_MOUSE_SOCKET_NAME: &str = "lan-mouse-socket.sock";
+
+#[derive(Debug, Error)]
+pub enum SocketPathError {
+    #[error("could not determine $XDG_RUNTIME_DIR: `{0}`")]
+    XdgRuntimeDirNotFound(VarError),
+    #[error("could not determine $HOME: `{0}`")]
+    HomeDirNotFound(VarError),
+}
+
+#[cfg(all(unix, not(target_os = "macos")))]
+pub fn default_socket_path() -> Result<PathBuf, SocketPathError> {
+    let xdg_runtime_dir =
+        env::var("XDG_RUNTIME_DIR").map_err(SocketPathError::XdgRuntimeDirNotFound)?;
+    Ok(Path::new(xdg_runtime_dir.as_str()).join(LAN_MOUSE_SOCKET_NAME))
+}
+
+#[cfg(all(unix, target_os = "macos"))]
+pub fn default_socket_path() -> Result<PathBuf, SocketPathError> {
+    let home = env::var("HOME").map_err(SocketPathError::HomeDirNotFound)?;
+    Ok(Path::new(home.as_str())
+        .join("Library")
+        .join("Caches")
+        .join(LAN_MOUSE_SOCKET_NAME))
+}

lan-mouse-ipc/src/listen.rs

@@ -0,0 +1,147 @@
+use futures::{stream::SelectAll, Stream, StreamExt};
+#[cfg(unix)]
+use std::path::PathBuf;
+use std::{
+    io::ErrorKind,
+    pin::Pin,
+    task::{Context, Poll},
+};
+
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader, ReadHalf, WriteHalf};
+use tokio_stream::wrappers::LinesStream;
+
+#[cfg(unix)]
+use tokio::net::UnixListener;
+#[cfg(unix)]
+use tokio::net::UnixStream;
+
+#[cfg(windows)]
+use tokio::net::TcpListener;
+#[cfg(windows)]
+use tokio::net::TcpStream;
+
+use crate::{FrontendEvent, FrontendRequest, IpcError, ListenerCreationError};
+
+pub struct AsyncFrontendListener {
+    #[cfg(windows)]
+    listener: TcpListener,
+    #[cfg(unix)]
+    listener: UnixListener,
+    #[cfg(unix)]
+    socket_path: PathBuf,
+    #[cfg(unix)]
+    line_streams: SelectAll<LinesStream<BufReader<ReadHalf<UnixStream>>>>,
+    #[cfg(windows)]
+    line_streams: SelectAll<LinesStream<BufReader<ReadHalf<TcpStream>>>>,
+    #[cfg(unix)]
+    tx_streams: Vec<WriteHalf<UnixStream>>,
+    #[cfg(windows)]
+    tx_streams: Vec<WriteHalf<TcpStream>>,
+}
+
+impl AsyncFrontendListener {
+    pub async fn new() -> Result<Self, ListenerCreationError> {
+        #[cfg(unix)]
+        let (socket_path, listener) = {
+            let socket_path = crate::default_socket_path()?;
+
+            log::debug!("remove socket: {:?}", socket_path);
+            if socket_path.exists() {
+                // try to connect to see if some other instance
+                // of lan-mouse is already running
+                match UnixStream::connect(&socket_path).await {
+                    // connected -> lan-mouse is already running
+                    Ok(_) => return Err(ListenerCreationError::AlreadyRunning),
+                    // lan-mouse is not running but a socket was left behind
+                    Err(e) => {
+                        log::debug!("{socket_path:?}: {e} - removing left behind socket");
+                        let _ = std::fs::remove_file(&socket_path);
+                    }
+                }
+            }
+            let listener = match UnixListener::bind(&socket_path) {
+                Ok(ls) => ls,
+                // some other lan-mouse instance has bound the socket in the meantime
+                Err(e) if e.kind() == ErrorKind::AddrInUse => {
+                    return Err(ListenerCreationError::AlreadyRunning)
+                }
+                Err(e) => return Err(ListenerCreationError::Bind(e)),
+            };
+            (socket_path, listener)
+        };
+
+        #[cfg(windows)]
+        let listener = match TcpListener::bind("127.0.0.1:5252").await {
+            Ok(ls) => ls,
+            // some other lan-mouse instance has bound the socket in the meantime
+            Err(e) if e.kind() == ErrorKind::AddrInUse => {
+                return Err(ListenerCreationError::AlreadyRunning)
+            }
+            Err(e) => return Err(ListenerCreationError::Bind(e)),
+        };
+
+        let adapter = Self {
+            listener,
+            #[cfg(unix)]
+            socket_path,
+            line_streams: SelectAll::new(),
+            tx_streams: vec![],
+        };
+
+        Ok(adapter)
+    }
+
+    pub async fn broadcast(&mut self, notify: FrontendEvent) {
+        // encode event
+        let mut json = serde_json::to_string(&notify).unwrap();
+        json.push('\n');
+
+        let mut keep = vec![];
+        // TODO do simultaneously
+        for tx in self.tx_streams.iter_mut() {
+            // write len + payload
+            if tx.write(json.as_bytes()).await.is_err() {
+                keep.push(false);
+                continue;
+            }
+            keep.push(true);
+        }
+
+        // could not find a better solution because async
+        let mut keep = keep.into_iter();
+        self.tx_streams.retain(|_| keep.next().unwrap());
+    }
+}
+
+#[cfg(unix)]
+impl Drop for AsyncFrontendListener {
+    fn drop(&mut self) {
+        log::debug!("remove socket: {:?}", self.socket_path);
+        let _ = std::fs::remove_file(&self.socket_path);
+    }
+}
+
+impl Stream for AsyncFrontendListener {
+    type Item = Result<FrontendRequest, IpcError>;
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        if let Poll::Ready(Some(Ok(l))) = self.line_streams.poll_next_unpin(cx) {
+            let request = serde_json::from_str(l.as_str()).map_err(|e| e.into());
+            return Poll::Ready(Some(request));
+        }
+        let mut sync = false;
+        while let Poll::Ready(Ok((stream, _))) = self.listener.poll_accept(cx) {
+            let (rx, tx) = tokio::io::split(stream);
+            let buf_reader = BufReader::new(rx);
+            let lines = buf_reader.lines();
+            let lines = LinesStream::new(lines);
+            self.line_streams.push(lines);
+            self.tx_streams.push(tx);
+            sync = true;
+        }
+        if sync {
+            Poll::Ready(Some(Ok(FrontendRequest::Sync)))
+        } else {
+            Poll::Pending
+        }
+    }
+}