Merge pull request #5 from helix-editor/lsp

LSP: mk1

1 files changed, 355 insertions, 0 deletions

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!()
+    }
+}