Merge pull request #5 from helix-editor/lsp

LSP: mk1

4 files changed, 710 insertions, 0 deletions

diff --git a/helix-lsp/Cargo.toml b/helix-lsp/Cargo.toml
new file mode 100644
index 00000000..2ecd0cc1
--- /dev/null
+++ b/helix-lsp/Cargo.toml
@@ -0,0 +1,26 @@
+[package]
+name = "helix-lsp"
+version = "0.1.0"
+authors = ["Blaž Hrastnik <blaz@mxxn.io>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+helix-core = { path = "../helix-core" }
+helix-view = { path = "../helix-view" }
+once_cell = "1.4"
+
+lsp-types = { version = "0.84", features = ["proposed"] }
+smol = "1.2"
+url = "2"
+pathdiff = "0.2"
+shellexpand = "2.0"
+glob = "0.3"
+anyhow = "1"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+jsonrpc-core = "15.1"
+futures-util = "0.3"
+thiserror = "1"
+log = "0.4"
diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
new file mode 100644
index 00000000..1f07cf89
--- /dev/null
+++ b/helix-lsp/src/client.rs
@@ -0,0 +1,355 @@
+use crate::{
+    transport::{Payload, Transport},
+    Call, Error,
+};
+
+type Result<T> = core::result::Result<T, Error>;
+
+use helix_core::{ChangeSet, Transaction};
+use helix_view::Document;
+
+// use std::collections::HashMap;
+use std::sync::atomic::{AtomicU64, Ordering};
+
+use jsonrpc_core as jsonrpc;
+use lsp_types as lsp;
+use serde_json::Value;
+
+use smol::{
+    channel::{Receiver, Sender},
+    io::{BufReader, BufWriter},
+    // prelude::*,
+    process::{Child, ChildStderr, Command, Stdio},
+    Executor,
+};
+
+pub struct Client {
+    _process: Child,
+    stderr: BufReader<ChildStderr>,
+
+    outgoing: Sender<Payload>,
+    pub incoming: Receiver<Call>,
+
+    pub request_counter: AtomicU64,
+
+    capabilities: Option<lsp::ServerCapabilities>,
+    // TODO: handle PublishDiagnostics Version
+    // diagnostics: HashMap<lsp::Url, Vec<lsp::Diagnostic>>,
+}
+
+impl Client {
+    pub fn start(ex: &Executor, cmd: &str, args: &[String]) -> Self {
+        let mut process = Command::new(cmd)
+            .args(args)
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()
+            .expect("Failed to start language server");
+        // smol makes sure the process is reaped on drop, but using kill_on_drop(true) maybe?
+
+        // TODO: do we need bufreader/writer here? or do we use async wrappers on unblock?
+        let writer = BufWriter::new(process.stdin.take().expect("Failed to open stdin"));
+        let reader = BufReader::new(process.stdout.take().expect("Failed to open stdout"));
+        let stderr = BufReader::new(process.stderr.take().expect("Failed to open stderr"));
+
+        let (incoming, outgoing) = Transport::start(ex, reader, writer);
+
+        Client {
+            _process: process,
+            stderr,
+
+            outgoing,
+            incoming,
+
+            request_counter: AtomicU64::new(0),
+
+            capabilities: None,
+            // diagnostics: HashMap::new(),
+        }
+    }
+
+    fn next_request_id(&self) -> jsonrpc::Id {
+        let id = self.request_counter.fetch_add(1, Ordering::Relaxed);
+        jsonrpc::Id::Num(id)
+    }
+
+    fn to_params(value: Value) -> Result<jsonrpc::Params> {
+        use jsonrpc::Params;
+
+        let params = match value {
+            Value::Null => Params::None,
+            Value::Bool(_) | Value::Number(_) | Value::String(_) => Params::Array(vec![value]),
+            Value::Array(vec) => Params::Array(vec),
+            Value::Object(map) => Params::Map(map),
+        };
+
+        Ok(params)
+    }
+
+    /// Execute a RPC request on the language server.
+    pub async fn request<R: lsp::request::Request>(&self, params: R::Params) -> Result<R::Result>
+    where
+        R::Params: serde::Serialize,
+        R::Result: core::fmt::Debug, // TODO: temporary
+    {
+        let params = serde_json::to_value(params)?;
+
+        let request = jsonrpc::MethodCall {
+            jsonrpc: Some(jsonrpc::Version::V2),
+            id: self.next_request_id(),
+            method: R::METHOD.to_string(),
+            params: Self::to_params(params)?,
+        };
+
+        let (tx, rx) = smol::channel::bounded::<Result<Value>>(1);
+
+        self.outgoing
+            .send(Payload::Request {
+                chan: tx,
+                value: request,
+            })
+            .await
+            .map_err(|e| Error::Other(e.into()))?;
+
+        let response = rx.recv().await.map_err(|e| Error::Other(e.into()))??;
+
+        let response = serde_json::from_value(response)?;
+
+        // TODO: we should pass request to a sender thread via a channel
+        // so it can't be interleaved
+
+        // TODO: responses can be out of order, we need to register a single shot response channel
+
+        Ok(response)
+    }
+
+    /// Send a RPC notification to the language server.
+    pub async fn notify<R: lsp::notification::Notification>(&self, params: R::Params) -> Result<()>
+    where
+        R::Params: serde::Serialize,
+    {
+        let params = serde_json::to_value(params)?;
+
+        let notification = jsonrpc::Notification {
+            jsonrpc: Some(jsonrpc::Version::V2),
+            method: R::METHOD.to_string(),
+            params: Self::to_params(params)?,
+        };
+
+        self.outgoing
+            .send(Payload::Notification(notification))
+            .await
+            .map_err(|e| Error::Other(e.into()))?;
+
+        Ok(())
+    }
+
+    /// Reply to a language server RPC call.
+    pub async fn reply(
+        &self,
+        id: jsonrpc::Id,
+        result: core::result::Result<Value, jsonrpc::Error>,
+    ) -> Result<()> {
+        use jsonrpc::{Failure, Output, Success, Version};
+
+        let output = match result {
+            Ok(result) => Output::Success(Success {
+                jsonrpc: Some(Version::V2),
+                id,
+                result,
+            }),
+            Err(error) => Output::Failure(Failure {
+                jsonrpc: Some(Version::V2),
+                id,
+                error,
+            }),
+        };
+
+        self.outgoing
+            .send(Payload::Response(output))
+            .await
+            .map_err(|e| Error::Other(e.into()))?;
+
+        Ok(())
+    }
+
+    // -------------------------------------------------------------------------------------------
+    // General messages
+    // -------------------------------------------------------------------------------------------
+
+    pub async fn initialize(&mut self) -> Result<()> {
+        // TODO: delay any requests that are triggered prior to initialize
+
+        #[allow(deprecated)]
+        let params = lsp::InitializeParams {
+            process_id: Some(std::process::id()),
+            root_path: None,
+            // root_uri: Some(lsp_types::Url::parse("file://localhost/")?),
+            root_uri: None, // set to project root in the future
+            initialization_options: None,
+            capabilities: lsp::ClientCapabilities {
+                ..Default::default()
+            },
+            trace: None,
+            workspace_folders: None,
+            client_info: None,
+            locale: None, // TODO
+        };
+
+        let response = self.request::<lsp::request::Initialize>(params).await?;
+        self.capabilities = Some(response.capabilities);
+
+        // next up, notify<initialized>
+        self.notify::<lsp::notification::Initialized>(lsp::InitializedParams {})
+            .await?;
+
+        Ok(())
+    }
+
+    pub async fn shutdown(&self) -> Result<()> {
+        self.request::<lsp::request::Shutdown>(()).await
+    }
+
+    pub async fn exit(&self) -> Result<()> {
+        self.notify::<lsp::notification::Exit>(()).await
+    }
+
+    // -------------------------------------------------------------------------------------------
+    // Text document
+    // -------------------------------------------------------------------------------------------
+
+    pub async fn text_document_did_open(&mut self, doc: &Document) -> Result<()> {
+        self.notify::<lsp::notification::DidOpenTextDocument>(lsp::DidOpenTextDocumentParams {
+            text_document: lsp::TextDocumentItem {
+                uri: lsp::Url::from_file_path(doc.path().unwrap()).unwrap(),
+                language_id: "rust".to_string(), // TODO: hardcoded for now
+                version: doc.version,
+                text: String::from(doc.text()),
+            },
+        })
+        .await
+    }
+
+    fn to_changes(changeset: &ChangeSet) -> Vec<lsp::TextDocumentContentChangeEvent> {
+        let mut iter = changeset.changes().iter().peekable();
+        let mut old_pos = 0;
+
+        let mut changes = Vec::new();
+
+        use crate::util::pos_to_lsp_pos;
+        use helix_core::Operation::*;
+
+        // TEMP
+        let rope = helix_core::Rope::from("");
+        let old_text = rope.slice(..);
+
+        while let Some(change) = iter.next() {
+            let len = match change {
+                Delete(i) | Retain(i) => *i,
+                Insert(_) => 0,
+            };
+            let old_end = old_pos + len;
+
+            match change {
+                Retain(_) => {}
+                Delete(_) => {
+                    let start = pos_to_lsp_pos(&old_text, old_pos);
+                    let end = pos_to_lsp_pos(&old_text, old_end);
+
+                    // a subsequent ins means a replace, consume it
+                    if let Some(Insert(s)) = iter.peek() {
+                        iter.next();
+
+                        // replacement
+                        changes.push(lsp::TextDocumentContentChangeEvent {
+                            range: Some(lsp::Range::new(start, end)),
+                            text: s.into(),
+                            range_length: None,
+                        });
+                    } else {
+                        // deletion
+                        changes.push(lsp::TextDocumentContentChangeEvent {
+                            range: Some(lsp::Range::new(start, end)),
+                            text: "".to_string(),
+                            range_length: None,
+                        });
+                    };
+                }
+                Insert(s) => {
+                    let start = pos_to_lsp_pos(&old_text, old_pos);
+
+                    // insert
+                    changes.push(lsp::TextDocumentContentChangeEvent {
+                        range: Some(lsp::Range::new(start, start)),
+                        text: s.into(),
+                        range_length: None,
+                    });
+                }
+            }
+            old_pos = old_end;
+        }
+
+        changes
+    }
+
+    // TODO: trigger any time history.commit_revision happens
+    pub async fn text_document_did_change(
+        &mut self,
+        doc: &Document,
+        transaction: &Transaction,
+    ) -> Result<()> {
+        // figure out what kind of sync the server supports
+
+        let capabilities = self.capabilities.as_ref().unwrap(); // TODO: needs post init
+
+        let sync_capabilities = match capabilities.text_document_sync {
+            Some(lsp::TextDocumentSyncCapability::Kind(kind)) => kind,
+            Some(lsp::TextDocumentSyncCapability::Options(lsp::TextDocumentSyncOptions {
+                change: Some(kind),
+                ..
+            })) => kind,
+            // None | SyncOptions { changes: None }
+            _ => return Ok(()),
+        };
+
+        let changes = match sync_capabilities {
+            lsp::TextDocumentSyncKind::Full => {
+                vec![lsp::TextDocumentContentChangeEvent {
+                    // range = None -> whole document
+                    range: None,        //Some(Range)
+                    range_length: None, // u64 apparently deprecated
+                    text: "".to_string(),
+                }] // TODO: probably need old_state here too?
+            }
+            lsp::TextDocumentSyncKind::Incremental => Self::to_changes(transaction.changes()),
+            lsp::TextDocumentSyncKind::None => return Ok(()),
+        };
+
+        self.notify::<lsp::notification::DidChangeTextDocument>(lsp::DidChangeTextDocumentParams {
+            text_document: lsp::VersionedTextDocumentIdentifier::new(
+                lsp::Url::from_file_path(doc.path().unwrap()).unwrap(),
+                doc.version,
+            ),
+            content_changes: changes,
+        })
+        .await
+    }
+
+    // TODO: impl into() TextDocumentIdentifier / VersionedTextDocumentIdentifier for Document.
+
+    pub async fn text_document_did_close(&mut self, doc: &Document) -> Result<()> {
+        self.notify::<lsp::notification::DidCloseTextDocument>(lsp::DidCloseTextDocumentParams {
+            text_document: lsp::TextDocumentIdentifier::new(
+                lsp::Url::from_file_path(doc.path().unwrap()).unwrap(),
+            ),
+        })
+        .await
+    }
+
+    // will_save / will_save_wait_until
+
+    pub async fn text_document_did_save(&mut self) -> anyhow::Result<()> {
+        unimplemented!()
+    }
+}
diff --git a/helix-lsp/src/lib.rs b/helix-lsp/src/lib.rs
new file mode 100644
index 00000000..eae6fa86
--- /dev/null
+++ b/helix-lsp/src/lib.rs
@@ -0,0 +1,117 @@
+mod client;
+mod transport;
+
+pub use jsonrpc_core as jsonrpc;
+pub use lsp_types as lsp;
+
+pub use once_cell::sync::{Lazy, OnceCell};
+
+pub use client::Client;
+pub use lsp::{Position, Url};
+
+use thiserror::Error;
+
+use std::{collections::HashMap, sync::Arc};
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("protocol error: {0}")]
+    Rpc(#[from] jsonrpc::Error),
+    #[error("failed to parse: {0}")]
+    Parse(#[from] serde_json::Error),
+    #[error("request timed out")]
+    Timeout,
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
+pub mod util {
+    use super::*;
+
+    pub fn lsp_pos_to_pos(doc: &helix_core::RopeSlice, pos: lsp::Position) -> usize {
+        let line = doc.line_to_char(pos.line as usize);
+        let line_start = doc.char_to_utf16_cu(line);
+        doc.utf16_cu_to_char(pos.character as usize + line_start)
+    }
+    pub fn pos_to_lsp_pos(doc: &helix_core::RopeSlice, pos: usize) -> lsp::Position {
+        let line = doc.char_to_line(pos);
+        let line_start = doc.char_to_utf16_cu(line);
+        let col = doc.char_to_utf16_cu(pos) - line_start;
+
+        lsp::Position::new(line as u32, col as u32)
+    }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Notification {
+    PublishDiagnostics(lsp::PublishDiagnosticsParams),
+}
+
+impl Notification {
+    pub fn parse(method: &str, params: jsonrpc::Params) -> Notification {
+        use lsp::notification::Notification as _;
+
+        match method {
+            lsp::notification::PublishDiagnostics::METHOD => {
+                let params: lsp::PublishDiagnosticsParams = params
+                    .parse()
+                    .expect("Failed to parse PublishDiagnostics params");
+
+                // TODO: need to loop over diagnostics and distinguish them by URI
+                Notification::PublishDiagnostics(params)
+            }
+            _ => unimplemented!("unhandled notification: {}", method),
+        }
+    }
+}
+
+pub use jsonrpc::Call;
+
+type LanguageId = String;
+
+pub static REGISTRY: Lazy<Registry> = Lazy::new(Registry::init);
+
+pub struct Registry {
+    inner: HashMap<LanguageId, OnceCell<Arc<Client>>>,
+}
+
+impl Registry {
+    pub fn init() -> Self {
+        Self {
+            inner: HashMap::new(),
+        }
+    }
+
+    pub fn get(&self, id: &str, ex: &smol::Executor) -> Option<Arc<Client>> {
+        // TODO: use get_or_try_init and propagate the error
+        self.inner
+            .get(id)
+            .map(|cell| {
+                cell.get_or_init(|| {
+                    // TODO: lookup defaults for id (name, args)
+
+                    // initialize a new client
+                    let client = Client::start(&ex, "rust-analyzer", &[]);
+                    // TODO: also call initialize().await()
+                    Arc::new(client)
+                })
+            })
+            .cloned()
+    }
+}
+
+// REGISTRY = HashMap<LanguageId, Lazy/OnceCell<Arc<RwLock<Client>>>
+// spawn one server per language type, need to spawn one per workspace if server doesn't support
+// workspaces
+//
+// could also be a client per root dir
+//
+// storing a copy of Option<Arc<RwLock<Client>>> on Document would make the LSP client easily
+// accessible during edit/save callbacks
+//
+// the event loop needs to process all incoming streams, maybe we can just have that be a separate
+// task that's continually running and store the state on the client, then use read lock to
+// retrieve data during render
+// -> PROBLEM: how do you trigger an update on the editor side when data updates?
+//
+// -> The data updates should pull all events until we run out so we don't frequently re-render
diff --git a/helix-lsp/src/transport.rs b/helix-lsp/src/transport.rs
new file mode 100644
index 00000000..4c349a13
--- /dev/null
+++ b/helix-lsp/src/transport.rs
@@ -0,0 +1,212 @@
+use std::collections::HashMap;
+
+use log::debug;
+
+use crate::{Error, Notification};
+
+type Result<T> = core::result::Result<T, Error>;
+
+use jsonrpc_core as jsonrpc;
+use serde_json::Value;
+
+use smol::prelude::*;
+
+use smol::{
+    channel::{Receiver, Sender},
+    io::{BufReader, BufWriter},
+    process::{ChildStderr, ChildStdin, ChildStdout},
+    Executor,
+};
+
+pub(crate) enum Payload {
+    Request {
+        chan: Sender<Result<Value>>,
+        value: jsonrpc::MethodCall,
+    },
+    Notification(jsonrpc::Notification),
+    Response(jsonrpc::Output),
+}
+
+use serde::{Deserialize, Serialize};
+/// A type representing all possible values sent from the server to the client.
+#[derive(Debug, PartialEq, Clone, Deserialize, Serialize)]
+#[serde(deny_unknown_fields)]
+#[serde(untagged)]
+enum Message {
+    /// A regular JSON-RPC request output (single response).
+    Output(jsonrpc::Output),
+    /// A JSON-RPC request or notification.
+    Call(jsonrpc::Call),
+}
+
+pub(crate) struct Transport {
+    incoming: Sender<jsonrpc::Call>,
+    outgoing: Receiver<Payload>,
+
+    pending_requests: HashMap<jsonrpc::Id, Sender<Result<Value>>>,
+    headers: HashMap<String, String>,
+
+    writer: BufWriter<ChildStdin>,
+    reader: BufReader<ChildStdout>,
+}
+
+impl Transport {
+    pub fn start(
+        ex: &Executor,
+        reader: BufReader<ChildStdout>,
+        writer: BufWriter<ChildStdin>,
+    ) -> (Receiver<jsonrpc::Call>, Sender<Payload>) {
+        let (incoming, rx) = smol::channel::unbounded();
+        let (tx, outgoing) = smol::channel::unbounded();
+
+        let transport = Self {
+            reader,
+            writer,
+            incoming,
+            outgoing,
+            pending_requests: Default::default(),
+            headers: Default::default(),
+        };
+
+        ex.spawn(transport.duplex()).detach();
+
+        (rx, tx)
+    }
+
+    async fn recv(
+        reader: &mut (impl AsyncBufRead + Unpin),
+        headers: &mut HashMap<String, String>,
+    ) -> core::result::Result<Message, std::io::Error> {
+        // read headers
+        loop {
+            let mut header = String::new();
+            // detect pipe closed if 0
+            reader.read_line(&mut header).await?;
+            let header = header.trim();
+
+            if header.is_empty() {
+                break;
+            }
+
+            let parts: Vec<&str> = header.split(": ").collect();
+            if parts.len() != 2 {
+                return Err(std::io::Error::new(
+                    std::io::ErrorKind::Other,
+                    "Failed to parse header",
+                ));
+            }
+            headers.insert(parts[0].to_string(), parts[1].to_string());
+        }
+
+        // find content-length
+        let content_length = headers.get("Content-Length").unwrap().parse().unwrap();
+
+        let mut content = vec![0; content_length];
+        reader.read_exact(&mut content).await?;
+        let msg = String::from_utf8(content).unwrap();
+
+        // read data
+
+        // try parsing as output (server response) or call (server request)
+        let output: serde_json::Result<Message> = serde_json::from_str(&msg);
+
+        Ok(output?)
+    }
+
+    pub async fn send_payload(&mut self, payload: Payload) -> anyhow::Result<()> {
+        match payload {
+            Payload::Request { chan, value } => {
+                self.pending_requests.insert(value.id.clone(), chan);
+
+                let json = serde_json::to_string(&value)?;
+                self.send(json).await
+            }
+            Payload::Notification(value) => {
+                let json = serde_json::to_string(&value)?;
+                self.send(json).await
+            }
+            Payload::Response(error) => {
+                let json = serde_json::to_string(&error)?;
+                self.send(json).await
+            }
+        }
+    }
+
+    pub async fn send(&mut self, request: String) -> anyhow::Result<()> {
+        debug!("-> {}", request);
+
+        // send the headers
+        self.writer
+            .write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes())
+            .await?;
+
+        // send the body
+        self.writer.write_all(request.as_bytes()).await?;
+
+        self.writer.flush().await?;
+
+        Ok(())
+    }
+
+    async fn recv_msg(&mut self, msg: Message) -> anyhow::Result<()> {
+        match msg {
+            Message::Output(output) => self.recv_response(output).await?,
+            Message::Call(call) => {
+                self.incoming.send(call).await?;
+                // let notification = Notification::parse(&method, params);
+            }
+        };
+        Ok(())
+    }
+
+    async fn recv_response(&mut self, output: jsonrpc::Output) -> anyhow::Result<()> {
+        match output {
+            jsonrpc::Output::Success(jsonrpc::Success { id, result, .. }) => {
+                debug!("<- {}", result);
+
+                let tx = self
+                    .pending_requests
+                    .remove(&id)
+                    .expect("pending_request with id not found!");
+                tx.send(Ok(result)).await?;
+            }
+            jsonrpc::Output::Failure(jsonrpc::Failure { id, error, .. }) => {
+                let tx = self
+                    .pending_requests
+                    .remove(&id)
+                    .expect("pending_request with id not found!");
+                tx.send(Err(error.into())).await?;
+            }
+            msg => unimplemented!("{:?}", msg),
+        }
+        Ok(())
+    }
+
+    pub async fn duplex(mut self) {
+        use futures_util::{select, FutureExt};
+        loop {
+            select! {
+                // client -> server
+                msg = self.outgoing.next().fuse() => {
+                    if msg.is_none() {
+                        break;
+                    }
+                    let msg = msg.unwrap();
+
+                    self.send_payload(msg).await.unwrap();
+                }
+                // server <- client
+                msg = Self::recv(&mut self.reader, &mut self.headers).fuse() => {
+                    if msg.is_err() {
+                        break;
+                    }
+                    let msg = msg.unwrap();
+
+                    debug!("<- {:?}", msg);
+
+                    self.recv_msg(msg).await.unwrap();
+                }
+            }
+        }
+    }
+}