fwd/src/message.rs
2024-08-10 06:48:24 -07:00

360 lines
10 KiB
Rust

use bytes::{Buf, BufMut, Bytes, BytesMut};
use std::io::Cursor;
use thiserror::Error;
use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
// ----------------------------------------------------------------------------
// Errors
#[derive(Debug, Error)]
pub enum Error {
#[error("Message type unknown: {0}")]
Unknown(u8),
#[error("Message incomplete")]
Incomplete,
#[error("String contained invalid UTF8: {0}")]
InvalidString(std::str::Utf8Error),
#[error("IO Error occurred: {0}")]
IO(std::io::Error),
}
impl From<std::str::Utf8Error> for Error {
fn from(value: std::str::Utf8Error) -> Self {
Self::InvalidString(value)
}
}
impl From<std::io::Error> for Error {
fn from(value: std::io::Error) -> Self {
Self::IO(value)
}
}
pub type Result<T> = std::result::Result<T, Error>;
// ----------------------------------------------------------------------------
// Messages
#[derive(Debug, PartialEq, Clone)]
pub struct PortDesc {
pub port: u16,
pub desc: String,
}
#[derive(Debug, PartialEq, Clone)]
pub enum Message {
// Ignored on both sides, can be used to test connection.
Ping,
// Server info announcement: major version, minor version, headers.
Hello(u8, u8, Vec<String>),
// Request to refresh list of ports from client.
Refresh,
// List of available ports from server to client.
Ports(Vec<PortDesc>),
// Browse a thing
Browse(String),
// Send data to the remote clipboard
ClipStart(u64),
ClipData(u64, Vec<u8>),
ClipEnd(u64),
}
impl Message {
pub fn encode(self: &Message) -> BytesMut {
let mut result = BytesMut::new();
self.encode_buf(&mut result);
result
}
pub fn encode_buf<T: BufMut>(self: &Message, result: &mut T) {
use Message::*;
match self {
Ping => {
result.put_u8(0x00);
}
Hello(major, minor, details) => {
result.put_u8(0x01);
result.put_u8(*major);
result.put_u8(*minor);
result.put_u16(
details.len().try_into().expect("Too many details"),
);
for detail in details {
put_string(result, detail);
}
}
Refresh => {
result.put_u8(0x05);
}
Ports(ports) => {
result.put_u8(0x06);
result.put_u16(ports.len().try_into().expect("Too many ports"));
for port in ports {
result.put_u16(port.port);
// Port descriptions can be long, let's make sure they're not.
let sliced = slice_up_to(&port.desc, u16::MAX.into());
put_string(result, sliced);
}
}
Browse(url) => {
result.put_u8(0x07);
put_string(result, url);
}
ClipStart(id) => {
result.put_u8(0x08);
result.put_u64(*id);
}
ClipData(id, data) => {
result.put_u8(0x09);
result.put_u64(*id);
put_data(result, data);
}
ClipEnd(id) => {
result.put_u8(0x0A);
result.put_u64(*id);
}
};
}
pub fn decode(cursor: &mut Cursor<&[u8]>) -> Result<Message> {
use Message::*;
match get_u8(cursor)? {
0x00 => Ok(Ping),
0x01 => {
let major = get_u8(cursor)?;
let minor = get_u8(cursor)?;
let count = get_u16(cursor)?;
let mut details = Vec::with_capacity(count.into());
for _ in 0..count {
details.push(get_string(cursor)?);
}
Ok(Hello(major, minor, details))
}
0x05 => Ok(Refresh),
0x06 => {
let count = get_u16(cursor)?;
let mut ports = Vec::with_capacity(count.into());
for _ in 0..count {
let port = get_u16(cursor)?;
let desc = get_string(cursor)?;
ports.push(PortDesc { port, desc });
}
Ok(Ports(ports))
}
0x07 => Ok(Browse(get_string(cursor)?)),
0x08 => {
let id = get_u64(cursor)?;
Ok(ClipStart(id))
}
0x09 => {
let id = get_u64(cursor)?;
let data = get_data(cursor)?;
Ok(Self::ClipData(id, data))
}
0x0A => {
let id = get_u64(cursor)?;
Ok(ClipEnd(id))
}
b => Err(Error::Unknown(b)),
}
}
}
fn get_u8(cursor: &mut Cursor<&[u8]>) -> Result<u8> {
if !cursor.has_remaining() {
return Err(Error::Incomplete);
}
Ok(cursor.get_u8())
}
fn get_u16(cursor: &mut Cursor<&[u8]>) -> Result<u16> {
if cursor.remaining() < 2 {
return Err(Error::Incomplete);
}
Ok(cursor.get_u16())
}
fn get_u64(cursor: &mut Cursor<&[u8]>) -> Result<u64> {
if cursor.remaining() < 8 {
return Err(Error::Incomplete);
}
Ok(cursor.get_u64())
}
fn get_bytes(cursor: &mut Cursor<&[u8]>, length: usize) -> Result<Bytes> {
if cursor.remaining() < length {
return Err(Error::Incomplete);
}
Ok(cursor.copy_to_bytes(length))
}
fn get_string(cursor: &mut Cursor<&[u8]>) -> Result<String> {
let length = get_u16(cursor)?;
let data = get_bytes(cursor, length.into())?;
Ok(std::str::from_utf8(&data[..])?.to_owned())
}
fn slice_up_to(s: &str, max_len: usize) -> &str {
if max_len >= s.len() {
return s;
}
let mut idx = max_len;
while !s.is_char_boundary(idx) {
idx -= 1;
}
&s[..idx]
}
fn put_string<T: BufMut>(target: &mut T, str: &str) {
target.put_u16(str.len().try_into().expect("String is too long"));
target.put_slice(str.as_bytes());
}
fn put_data<T: BufMut>(target: &mut T, data: &[u8]) {
target.put_u16(data.len().try_into().expect("Buffer is too long"));
target.put_slice(data);
}
fn get_data(cursor: &mut Cursor<&[u8]>) -> Result<Vec<u8>> {
let length = get_u16(cursor)?;
if cursor.remaining() < length.into() {
return Err(Error::Incomplete);
}
let mut data: Vec<u8> = vec![0; length.into()];
cursor.copy_to_slice(&mut data);
Ok(data)
}
// ----------------------------------------------------------------------------
// Message IO
pub struct MessageWriter<T: AsyncWrite + Unpin> {
writer: T,
}
impl<T: AsyncWrite + Unpin> MessageWriter<T> {
pub fn new(writer: T) -> MessageWriter<T> {
MessageWriter { writer }
}
pub async fn write(&mut self, msg: Message) -> Result<()> {
// TODO: Optimize buffer usage please this is bad
// eprintln!("? {:?}", msg);
let buffer = msg.encode();
self.writer
.write_u32(buffer.len().try_into().expect("Message too large"))
.await?;
self.writer.write_all(&buffer).await?;
self.writer.flush().await?;
Ok(())
}
}
pub struct MessageReader<T: AsyncRead + Unpin> {
reader: T,
}
impl<T: AsyncRead + Unpin> MessageReader<T> {
pub fn new(reader: T) -> MessageReader<T> {
MessageReader { reader }
}
pub async fn read(&mut self) -> Result<Message> {
let frame_length = self.reader.read_u32().await?;
let mut data = vec![0; frame_length.try_into().unwrap()];
self.reader.read_exact(&mut data).await?;
let mut cursor = Cursor::new(&data[..]);
Message::decode(&mut cursor)
}
}
#[cfg(test)]
mod message_tests {
use crate::message::Message::*;
use crate::message::PortDesc;
use crate::message::{Message, MessageReader, MessageWriter};
fn assert_round_trip(message: Message) {
let encoded = message.encode();
let mut cursor = std::io::Cursor::new(&encoded[..]);
let result = Message::decode(&mut cursor).unwrap();
assert_eq!(message.clone(), result);
let rt = tokio::runtime::Builder::new_current_thread()
.enable_all()
.build()
.expect("Unable to start tokio runtime");
rt.block_on(async move {
let (client, server) = tokio::io::duplex(64);
let expected = message.clone();
let write = tokio::spawn(async move {
let mut writer = MessageWriter::new(client);
writer.write(message).await.expect("Write failed");
});
let read = tokio::spawn(async move {
let mut reader = MessageReader::new(server);
let actual = reader.read().await.expect("Read failed");
assert_eq!(expected, actual);
});
write.await.expect("Write proc failed");
read.await.expect("Read proc failed");
});
}
#[test]
fn round_trip() {
assert_round_trip(Ping);
assert_round_trip(Hello(
0x12,
0x00,
vec!["One".to_string(), "Two".to_string(), "Three".to_string()],
));
assert_round_trip(Hello(0x00, 0x01, vec![]));
assert_round_trip(Refresh);
assert_round_trip(Ports(vec![]));
assert_round_trip(Ports(vec![
PortDesc {
port: 8080,
desc: "query-service".to_string(),
},
PortDesc {
port: 9090,
desc: "metadata-library".to_string(),
},
]));
assert_round_trip(Browse("https://google.com/".to_string()));
assert_round_trip(ClipStart(0x1234567890ABCDEF));
assert_round_trip(ClipData(
0x1234567890ABCDEF,
vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
));
assert_round_trip(ClipEnd(0x1234567890ABCDEF));
}
#[test]
fn big_port_desc() {
// Strings are capped at 64k let's make a big one!
let char = String::from_utf8(vec![0xe0, 0xa0, 0x83]).unwrap();
let mut str = String::with_capacity(128 * 1024);
while str.len() < 128 * 1024 {
str.push_str(&char);
}
let msg = Ports(vec![PortDesc { port: 8080, desc: str }]);
msg.encode();
}
}