Introduce zed_rpc::proto module containing protobuf stream logic

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

Cargo.lock

@@ -239,7 +239,7 @@ dependencies = [
  "regex",
  "rustc-hash",
  "shlex",
- "which",
+ "which 3.1.1",
 ]
 
 [[package]]
@@ -306,6 +306,12 @@ version = "1.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ae44d1a3d5a19df61dd0c8beb138458ac2a53a7ac09eba97d55592540004306b"
 
+[[package]]
+name = "bytes"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b700ce4376041dcd0a327fd0097c41095743c4c8af8887265942faf1100bd040"
+
 [[package]]
 name = "cab"
 version = "0.1.0"
@@ -893,6 +899,12 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "fixedbitset"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37ab347416e802de484e4d03c7316c48f1ecb56574dfd4a46a80f173ce1de04d"
+
 [[package]]
 name = "flate2"
 version = "1.0.20"
@@ -1067,9 +1079,9 @@ checksum = "28be053525281ad8259d47e4de5de657b25e7bac113458555bb4b70bc6870500"
 
 [[package]]
 name = "futures-lite"
-version = "1.11.3"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4481d0cd0de1d204a4fa55e7d45f07b1d958abcb06714b3446438e2eff695fb"
+checksum = "7694489acd39452c77daa48516b894c153f192c3578d5a839b62c58099fcbf48"
 dependencies = [
  "fastrand",
  "futures-core",
@@ -1249,6 +1261,15 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
 
+[[package]]
+name = "heck"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d621efb26863f0e9924c6ac577e8275e5e6b77455db64ffa6c65c904e9e132c"
+dependencies = [
+ "unicode-segmentation",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.18"
@@ -1354,6 +1375,24 @@ dependencies = [
  "cfg-if 1.0.0",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "284f18f85651fe11e8a991b2adb42cb078325c996ed026d994719efcfca1d54b"
+dependencies = [
+ "either",
+]
+
+[[package]]
+name = "itertools"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69ddb889f9d0d08a67338271fa9b62996bc788c7796a5c18cf057420aaed5eaf"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "0.3.4"
@@ -1577,6 +1616,12 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "multimap"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5ce46fe64a9d73be07dcbe690a38ce1b293be448fd8ce1e6c1b8062c9f72c6a"
+
 [[package]]
 name = "nb-connect"
 version = "1.0.3"
@@ -1808,6 +1853,16 @@ version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
 
+[[package]]
+name = "petgraph"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "467d164a6de56270bd7c4d070df81d07beace25012d5103ced4e9ff08d6afdb7"
+dependencies = [
+ "fixedbitset",
+ "indexmap",
+]
+
 [[package]]
 name = "phf"
 version = "0.7.24"
@@ -1976,6 +2031,76 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "prost"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e6984d2f1a23009bd270b8bb56d0926810a3d483f59c987d77969e9d8e840b2"
+dependencies = [
+ "bytes",
+ "prost-derive 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "prost"
+version = "0.7.0"
+source = "git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728#082f3e65874fe91382e72482863896b7b4db3728"
+dependencies = [
+ "bytes",
+ "prost-derive 0.7.0 (git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728)",
+]
+
+[[package]]
+name = "prost-build"
+version = "0.7.0"
+source = "git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728#082f3e65874fe91382e72482863896b7b4db3728"
+dependencies = [
+ "bytes",
+ "heck",
+ "itertools 0.10.1",
+ "log",
+ "multimap",
+ "petgraph",
+ "prost 0.7.0 (git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728)",
+ "prost-types",
+ "tempfile",
+ "which 4.1.0",
+]
+
+[[package]]
+name = "prost-derive"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "169a15f3008ecb5160cba7d37bcd690a7601b6d30cfb87a117d45e59d52af5d4"
+dependencies = [
+ "anyhow",
+ "itertools 0.9.0",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "prost-derive"
+version = "0.7.0"
+source = "git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728#082f3e65874fe91382e72482863896b7b4db3728"
+dependencies = [
+ "anyhow",
+ "itertools 0.10.1",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "prost-types"
+version = "0.7.0"
+source = "git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728#082f3e65874fe91382e72482863896b7b4db3728"
+dependencies = [
+ "bytes",
+ "prost 0.7.0 (git+https://github.com/sfackler/prost?rev=082f3e65874fe91382e72482863896b7b4db3728)",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.9"
@@ -2763,6 +2888,20 @@ dependencies = [
  "remove_dir_all",
 ]
 
+[[package]]
+name = "tempfile"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dac1c663cfc93810f88aed9b8941d48cabf856a1b111c29a40439018d870eb22"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "rand 0.8.3",
+ "redox_syscall 0.2.5",
+ "remove_dir_all",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "term"
 version = "0.4.6"
@@ -2957,6 +3096,12 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "79bf4d5fc96546fdb73f9827097810bbda93b11a6770ff3a54e1f445d4135787"
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb0d2e7be6ae3a5fa87eed5fb451aff96f2573d2694942e40543ae0bbe19c796"
+
 [[package]]
 name = "unicode-vo"
 version = "0.1.0"
@@ -3094,6 +3239,16 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "which"
+version = "4.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b55551e42cbdf2ce2bedd2203d0cc08dba002c27510f86dab6d0ce304cba3dfe"
+dependencies = [
+ "either",
+ "libc",
+]
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -3214,8 +3369,13 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "base64",
+ "futures-io",
+ "futures-lite",
+ "prost 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "prost-build",
  "rand 0.8.3",
  "rsa",
+ "smol",
 ]
 
 [[package]]

zed-rpc/Cargo.toml

@@ -7,5 +7,14 @@ version = "0.1.0"
 [dependencies]
 anyhow = "1.0"
 base64 = "0.13"
+futures-io = "0.3"
+futures-lite = "1"
+prost = "0.7"
 rsa = "0.4"
 rand = "0.8"
+
+[build-dependencies]
+prost-build = { git = "https://github.com/sfackler/prost", rev = "082f3e65874fe91382e72482863896b7b4db3728" }
+
+[dev-dependencies]
+smol = "1.2.5"

zed-rpc/build.rs

@@ -0,0 +1,7 @@
+fn main() {
+    let mut build = prost_build::Config::new();
+    // build.protoc_arg("--experimental_allow_proto3_optional");
+    build
+        .compile_protos(&["proto/zed.proto"], &["proto"])
+        .unwrap();
+}

zed-rpc/proto/zed.proto

@@ -0,0 +1,27 @@
+syntax = "proto3";
+package zed.messages;
+
+message FromClient {
+    int32 id = 1;
+
+    oneof variant {
+        Auth auth = 2;
+    }
+
+    message Auth {
+        int32 user_id = 1;
+        string access_token = 2;
+    }
+}
+
+message FromServer {
+    optional int32 request_id = 1;
+
+    oneof variant {
+        Ack ack = 2;
+    }
+
+    message Ack {
+        optional string error_message = 1;
+    }
+}

zed-rpc/src/lib.rs

@@ -1 +1,2 @@
 pub mod auth;
+pub mod proto;

zed-rpc/src/proto.rs

@@ -0,0 +1,234 @@
+use futures_io::{AsyncRead, AsyncWrite};
+use futures_lite::{AsyncReadExt, AsyncWriteExt as _};
+use prost::Message;
+use std::io;
+
+include!(concat!(env!("OUT_DIR"), "/zed.messages.rs"));
+
+pub trait Request {
+    type Response;
+}
+
+impl Request for from_client::Auth {
+    type Response = from_server::Ack;
+}
+
+/// A stream of protobuf messages.
+pub struct MessageStream<T> {
+    byte_stream: T,
+    buffer: Vec<u8>,
+}
+
+impl<T> MessageStream<T> {
+    pub fn new(byte_stream: T) -> Self {
+        Self {
+            byte_stream,
+            buffer: Default::default(),
+        }
+    }
+}
+
+impl<T> MessageStream<T>
+where
+    T: AsyncWrite + Unpin,
+{
+    /// Write a given protobuf message to the stream.
+    pub async fn write_message(&mut self, message: &impl Message) -> futures_io::Result<()> {
+        self.buffer.clear();
+        message.encode_length_delimited(&mut self.buffer).unwrap();
+        self.byte_stream.write_all(&self.buffer).await
+    }
+}
+
+impl<T> MessageStream<T>
+where
+    T: AsyncRead + Unpin,
+{
+    /// Read a protobuf message of the given type from the stream.
+    pub async fn read_message<M: Message + Default>(&mut self) -> futures_io::Result<M> {
+        // Ensure the buffer is large enough to hold the maximum delimiter length
+        const MAX_DELIMITER_LEN: usize = 10;
+        self.buffer.clear();
+        self.buffer.resize(MAX_DELIMITER_LEN, 0);
+
+        // Read until a complete length delimiter can be decoded.
+        let mut read_start_offset = 0;
+        let (encoded_len, delimiter_len) = loop {
+            let bytes_read = self
+                .byte_stream
+                .read(&mut self.buffer[read_start_offset..])
+                .await?;
+            read_start_offset += bytes_read;
+
+            let mut buffer = &self.buffer[0..read_start_offset];
+            match prost::decode_length_delimiter(&mut buffer) {
+                Err(_) => {
+                    if read_start_offset >= MAX_DELIMITER_LEN {
+                        return Err(io::Error::new(
+                            io::ErrorKind::InvalidData,
+                            "invalid message length delimiter",
+                        ));
+                    }
+                }
+                Ok(encoded_len) => {
+                    let delimiter_len = read_start_offset - buffer.len();
+                    break (encoded_len, delimiter_len);
+                }
+            }
+        };
+
+        // Read the message itself.
+        self.buffer.resize(delimiter_len + encoded_len, 0);
+        self.byte_stream
+            .read_exact(&mut self.buffer[read_start_offset..])
+            .await?;
+        let message = M::decode(&self.buffer[delimiter_len..])?;
+
+        Ok(message)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::{
+        pin::Pin,
+        task::{Context, Poll},
+    };
+
+    #[test]
+    fn test_round_trip_message() {
+        smol::block_on(async {
+            let byte_stream = ChunkedStream {
+                bytes: Vec::new(),
+                read_offset: 0,
+                chunk_size: 3,
+            };
+
+            // In reality there will never be both `FromClient` and `FromServer` messages
+            // sent in the same direction on the same stream.
+            let message1 = FromClient {
+                id: 3,
+                variant: Some(from_client::Variant::Auth(from_client::Auth {
+                    user_id: 5,
+                    access_token: "the-access-token".into(),
+                })),
+            };
+            let message2 = FromServer {
+                request_id: Some(4),
+                variant: Some(from_server::Variant::Ack(from_server::Ack {
+                    error_message: Some(
+                        format!(
+                            "a {}long error message that requires a two-byte length delimiter",
+                            "very ".repeat(60)
+                        )
+                        .into(),
+                    ),
+                })),
+            };
+
+            let mut message_stream = MessageStream::new(byte_stream);
+            message_stream.write_message(&message1).await.unwrap();
+            message_stream.write_message(&message2).await.unwrap();
+            let decoded_message1 = message_stream.read_message::<FromClient>().await.unwrap();
+            let decoded_message2 = message_stream.read_message::<FromServer>().await.unwrap();
+            assert_eq!(decoded_message1, message1);
+            assert_eq!(decoded_message2, message2);
+        });
+    }
+
+    #[test]
+    fn test_read_message_when_length_delimiter_is_not_complete_in_first_read() {
+        smol::block_on(async {
+            let byte_stream = ChunkedStream {
+                bytes: Vec::new(),
+                read_offset: 0,
+                chunk_size: 2,
+            };
+
+            // This message is so long that its length delimiter requires three bytes,
+            // so it won't be delivered in a single read from the chunked byte stream.
+            let message = FromServer {
+                request_id: Some(4),
+                variant: Some(from_server::Variant::Ack(from_server::Ack {
+                    error_message: Some("long ".repeat(256 * 256).into()),
+                })),
+            };
+            assert!(prost::length_delimiter_len(message.encoded_len()) > byte_stream.chunk_size);
+
+            let mut message_stream = MessageStream::new(byte_stream);
+            message_stream.write_message(&message).await.unwrap();
+            let decoded_message = message_stream.read_message::<FromServer>().await.unwrap();
+            assert_eq!(decoded_message, message);
+        });
+    }
+
+    #[test]
+    fn test_protobuf_parse_error() {
+        smol::block_on(async {
+            let byte_stream = ChunkedStream {
+                bytes: Vec::new(),
+                read_offset: 0,
+                chunk_size: 2,
+            };
+
+            let message = FromClient {
+                id: 3,
+                variant: Some(from_client::Variant::Auth(from_client::Auth {
+                    user_id: 5,
+                    access_token: "the-access-token".into(),
+                })),
+            };
+
+            let mut message_stream = MessageStream::new(byte_stream);
+            message_stream.write_message(&message).await.unwrap();
+
+            // Read the wrong type of message from the stream.
+            let result = message_stream.read_message::<FromServer>().await;
+            assert_eq!(result.unwrap_err().kind(), io::ErrorKind::InvalidData);
+        });
+    }
+
+    struct ChunkedStream {
+        bytes: Vec<u8>,
+        read_offset: usize,
+        chunk_size: usize,
+    }
+
+    impl AsyncWrite for ChunkedStream {
+        fn poll_write(
+            mut self: Pin<&mut Self>,
+            _: &mut Context<'_>,
+            buf: &[u8],
+        ) -> Poll<io::Result<usize>> {
+            let bytes_written = buf.len().min(self.chunk_size);
+            self.bytes.extend_from_slice(&buf[0..bytes_written]);
+            Poll::Ready(Ok(bytes_written))
+        }
+
+        fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
+            Poll::Ready(Ok(()))
+        }
+
+        fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
+            Poll::Ready(Ok(()))
+        }
+    }
+
+    impl AsyncRead for ChunkedStream {
+        fn poll_read(
+            mut self: Pin<&mut Self>,
+            _: &mut Context<'_>,
+            buf: &mut [u8],
+        ) -> Poll<io::Result<usize>> {
+            let bytes_read = buf
+                .len()
+                .min(self.chunk_size)
+                .min(self.bytes.len() - self.read_offset);
+            let end_offset = self.read_offset + bytes_read;
+            buf[0..bytes_read].copy_from_slice(&self.bytes[self.read_offset..end_offset]);
+            self.read_offset = end_offset;
+            Poll::Ready(Ok(bytes_read))
+        }
+    }
+}