Convert to std::future::Future and async/await

This commit makes judicious use of `compat()` to convert between `std::future::Future` and the legacy `futures` 0.1 `Future` trait such that we can have native Rust async/await support without waiting for the `jsonrpsee` crate to be ready (see #58 for context). Naturally, this should be considered a breaking change for this library since it directly affects the public API for this crate, and it also increases the minimum supported Rust version to 1.39.0. It tentatively introduces a reliance on [`async-trait`] for the `LanguageServer` trait and it also relaxes the `'static` requirements for the `stdin` parameter for `Server`. [`async-trait`]: https://github.com/dtolnay/async-trait This does not yet resolve #13, since that would require either switching to `jsonrpsee`, once it's ready, or building a custom client solution for the `Printer`, converting it to a `Client` or similar.
ebkalderon · Feb 22, 2020 · 76f9a8a · 76f9a8a
1 parent cdad611
commit 76f9a8a
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diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        rust-version: [1.36.0, beta, nightly]
+        rust-version: [1.39.0, beta, nightly]
         include:
         - rust-version: nightly
           continue-on-error: true

diff --git a/Cargo.toml b/Cargo.toml
@@ -13,20 +13,22 @@ categories = ["asynchronous"]
 keywords = ["language-server", "lsp", "tower"]
 
 [dependencies]
-bytes = "0.4.12"
-futures = "0.1.28"
+async-trait = "0.1.24"
+bytes = "0.5.0"
+futures = { version = "0.3.2", features = ["compat"] }
 jsonrpc-core = "14.0.5"
 jsonrpc-derive = "14.0.5"
 log = "0.4.8"
 lsp-types = "0.68.0"
 nom = "5.0.1"
 serde = { version = "1.0.103", features = ["derive"] }
 serde_json = "1.0.40"
-tokio-codec = "0.1.1"
-tokio-executor = "0.1.9"
-tokio-io = "0.1.12"
-tower-service = "0.2.0"
+tokio = { version = "0.2.11", features = ["rt-core"] }
+tokio-util = { version = "0.2.0", features = ["codec"] }
+tower-service = "0.3.0"
 
 [dev-dependencies]
 env_logger = "0.7.1"
-tokio = "0.1.22"
+tokio = { version = "0.2.11", features = ["io-std", "macros", "test-util"] }
+tokio-test = "0.2.0"
+tower-test = "0.3.0"
diff --git a/examples/custom_notification.rs b/examples/custom_notification.rs
@@ -1,14 +1,12 @@
-use futures::future;
-use jsonrpc_core::{BoxFuture, Result};
-use lsp_types::notification::Notification;
-use lsp_types::request::GotoImplementationResponse;
+use jsonrpc_core::Result;
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
-use tower_lsp::lsp_types::request::GotoDefinitionResponse;
+use tower_lsp::lsp_types::notification::Notification;
+use tower_lsp::lsp_types::request::{GotoDefinitionResponse, GotoImplementationResponse};
 use tower_lsp::lsp_types::*;
 use tower_lsp::{LanguageServer, LspService, Printer, Server};
 
-#[derive(Debug, Eq, PartialEq, Clone, Deserialize, Serialize)]
+#[derive(Debug, Deserialize, Serialize)]
 struct CustomNotificationParams {
     title: String,
     message: String,
@@ -24,7 +22,7 @@ impl CustomNotificationParams {
 }
 
 #[derive(Debug)]
-struct CustomNotification {}
+enum CustomNotification {}
 
 impl Notification for CustomNotification {
     type Params = CustomNotificationParams;
@@ -34,19 +32,8 @@ impl Notification for CustomNotification {
 #[derive(Debug, Default)]
 struct Backend;
 
+#[tower_lsp::async_trait]
 impl LanguageServer for Backend {
-    type ShutdownFuture = BoxFuture<()>;
-    type SymbolFuture = BoxFuture<Option<Vec<SymbolInformation>>>;
-    type ExecuteFuture = BoxFuture<Option<Value>>;
-    type CompletionFuture = BoxFuture<Option<CompletionResponse>>;
-    type HoverFuture = BoxFuture<Option<Hover>>;
-    type SignatureHelpFuture = BoxFuture<Option<SignatureHelp>>;
-    type DeclarationFuture = BoxFuture<Option<GotoDefinitionResponse>>;
-    type DefinitionFuture = BoxFuture<Option<GotoDefinitionResponse>>;
-    type TypeDefinitionFuture = BoxFuture<Option<GotoDefinitionResponse>>;
-    type ImplementationFuture = BoxFuture<Option<GotoImplementationResponse>>;
-    type HighlightFuture = BoxFuture<Option<Vec<DocumentHighlight>>>;
-
     fn initialize(&self, _: &Printer, _: InitializeParams) -> Result<InitializeResult> {
         Ok(InitializeResult {
             server_info: None,
@@ -87,19 +74,19 @@ impl LanguageServer for Backend {
         })
     }
 
-    fn shutdown(&self) -> Self::ShutdownFuture {
-        Box::new(future::ok(()))
+    async fn shutdown(&self) -> Result<()> {
+        Ok(())
     }
 
-    fn symbol(&self, _: WorkspaceSymbolParams) -> Self::SymbolFuture {
-        Box::new(future::ok(None))
+    async fn symbol(&self, _: WorkspaceSymbolParams) -> Result<Option<Vec<SymbolInformation>>> {
+        Ok(None)
     }
 
-    fn execute_command(
+    async fn execute_command(
         &self,
         printer: &Printer,
         params: ExecuteCommandParams,
-    ) -> Self::ExecuteFuture {
+    ) -> Result<Option<Value>> {
         if &params.command == "custom.notification" {
             printer.send_notification::<CustomNotification>(CustomNotificationParams::new(
                 "Hello", "Message",
@@ -109,44 +96,59 @@ impl LanguageServer for Backend {
             MessageType::Info,
             format!("command executed!: {:?}", params),
         );
-        printer.apply_edit(WorkspaceEdit::default());
-        Box::new(future::ok(None))
+        Ok(None)
     }
 
-    fn completion(&self, _: CompletionParams) -> Self::CompletionFuture {
-        Box::new(future::ok(None))
+    async fn completion(&self, _: CompletionParams) -> Result<Option<CompletionResponse>> {
+        Ok(None)
     }
 
-    fn hover(&self, _: TextDocumentPositionParams) -> Self::HoverFuture {
-        Box::new(future::ok(None))
+    async fn hover(&self, _: TextDocumentPositionParams) -> Result<Option<Hover>> {
+        Ok(None)
     }
 
-    fn signature_help(&self, _: TextDocumentPositionParams) -> Self::SignatureHelpFuture {
-        Box::new(future::ok(None))
+    async fn signature_help(&self, _: TextDocumentPositionParams) -> Result<Option<SignatureHelp>> {
+        Ok(None)
     }
 
-    fn goto_declaration(&self, _: TextDocumentPositionParams) -> Self::DeclarationFuture {
-        Box::new(future::ok(None))
+    async fn goto_declaration(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoDefinitionResponse>> {
+        Ok(None)
     }
 
-    fn goto_definition(&self, _: TextDocumentPositionParams) -> Self::DefinitionFuture {
-        Box::new(future::ok(None))
+    async fn goto_definition(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoDefinitionResponse>> {
+        Ok(None)
     }
 
-    fn goto_type_definition(&self, _: TextDocumentPositionParams) -> Self::TypeDefinitionFuture {
-        Box::new(future::ok(None))
+    async fn goto_type_definition(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoDefinitionResponse>> {
+        Ok(None)
     }
 
-    fn goto_implementation(&self, _: TextDocumentPositionParams) -> Self::ImplementationFuture {
-        Box::new(future::ok(None))
+    async fn goto_implementation(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoImplementationResponse>> {
+        Ok(None)
     }
 
-    fn document_highlight(&self, _: TextDocumentPositionParams) -> Self::HighlightFuture {
-        Box::new(future::ok(None))
+    async fn document_highlight(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<Vec<DocumentHighlight>>> {
+        Ok(None)
     }
 }
 
-fn main() {
+#[tokio::main]
+async fn main() {
     env_logger::init();
 
     let stdin = tokio::io::stdin();
@@ -158,5 +160,5 @@ fn main() {
         .interleave(messages)
         .serve(service);
 
-    tokio::run(handle.run_until_exit(server));
+    handle.run_until_exit(server).await;
 }
diff --git a/examples/server.rs b/examples/server.rs
@@ -1,5 +1,4 @@
-use futures::future;
-use jsonrpc_core::{BoxFuture, Result};
+use jsonrpc_core::Result;
 use serde_json::Value;
 use tower_lsp::lsp_types::request::{GotoDefinitionResponse, GotoImplementationResponse};
 use tower_lsp::lsp_types::*;
@@ -8,19 +7,8 @@ use tower_lsp::{LanguageServer, LspService, Printer, Server};
 #[derive(Debug, Default)]
 struct Backend;
 
+#[tower_lsp::async_trait]
 impl LanguageServer for Backend {
-    type ShutdownFuture = BoxFuture<()>;
-    type SymbolFuture = BoxFuture<Option<Vec<SymbolInformation>>>;
-    type ExecuteFuture = BoxFuture<Option<Value>>;
-    type CompletionFuture = BoxFuture<Option<CompletionResponse>>;
-    type HoverFuture = BoxFuture<Option<Hover>>;
-    type SignatureHelpFuture = BoxFuture<Option<SignatureHelp>>;
-    type DeclarationFuture = BoxFuture<Option<GotoDefinitionResponse>>;
-    type DefinitionFuture = BoxFuture<Option<GotoDefinitionResponse>>;
-    type TypeDefinitionFuture = BoxFuture<Option<GotoDefinitionResponse>>;
-    type ImplementationFuture = BoxFuture<Option<GotoImplementationResponse>>;
-    type HighlightFuture = BoxFuture<Option<Vec<DocumentHighlight>>>;
-
     fn initialize(&self, _: &Printer, _: InitializeParams) -> Result<InitializeResult> {
         Ok(InitializeResult {
             server_info: None,
@@ -62,12 +50,12 @@ impl LanguageServer for Backend {
         printer.log_message(MessageType::Info, "server initialized!");
     }
 
-    fn shutdown(&self) -> Self::ShutdownFuture {
-        Box::new(future::ok(()))
+    async fn shutdown(&self) -> Result<()> {
+        Ok(())
     }
 
-    fn symbol(&self, _: WorkspaceSymbolParams) -> Self::SymbolFuture {
-        Box::new(future::ok(None))
+    async fn symbol(&self, _: WorkspaceSymbolParams) -> Result<Option<Vec<SymbolInformation>>> {
+        Ok(None)
     }
 
     fn did_change_workspace_folders(&self, printer: &Printer, _: DidChangeWorkspaceFoldersParams) {
@@ -82,10 +70,14 @@ impl LanguageServer for Backend {
         printer.log_message(MessageType::Info, "watched files have changed!");
     }
 
-    fn execute_command(&self, printer: &Printer, _: ExecuteCommandParams) -> Self::ExecuteFuture {
+    async fn execute_command(
+        &self,
+        printer: &Printer,
+        _: ExecuteCommandParams,
+    ) -> Result<Option<Value>> {
         printer.log_message(MessageType::Info, "command executed!");
         printer.apply_edit(WorkspaceEdit::default());
-        Box::new(future::ok(None))
+        Ok(None)
     }
 
     fn did_open(&self, printer: &Printer, _: DidOpenTextDocumentParams) {
@@ -104,40 +96,56 @@ impl LanguageServer for Backend {
         printer.log_message(MessageType::Info, "file closed!");
     }
 
-    fn completion(&self, _: CompletionParams) -> Self::CompletionFuture {
-        Box::new(future::ok(None))
+    async fn completion(&self, _: CompletionParams) -> Result<Option<CompletionResponse>> {
+        Ok(None)
     }
 
-    fn hover(&self, _: TextDocumentPositionParams) -> Self::HoverFuture {
-        Box::new(future::ok(None))
+    async fn hover(&self, _: TextDocumentPositionParams) -> Result<Option<Hover>> {
+        Ok(None)
     }
 
-    fn signature_help(&self, _: TextDocumentPositionParams) -> Self::SignatureHelpFuture {
-        Box::new(future::ok(None))
+    async fn signature_help(&self, _: TextDocumentPositionParams) -> Result<Option<SignatureHelp>> {
+        Ok(None)
     }
 
-    fn goto_declaration(&self, _: TextDocumentPositionParams) -> Self::DeclarationFuture {
-        Box::new(future::ok(None))
+    async fn goto_declaration(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoDefinitionResponse>> {
+        Ok(None)
     }
 
-    fn goto_definition(&self, _: TextDocumentPositionParams) -> Self::DefinitionFuture {
-        Box::new(future::ok(None))
+    async fn goto_definition(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoDefinitionResponse>> {
+        Ok(None)
     }
 
-    fn goto_type_definition(&self, _: TextDocumentPositionParams) -> Self::TypeDefinitionFuture {
-        Box::new(future::ok(None))
+    async fn goto_type_definition(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoDefinitionResponse>> {
+        Ok(None)
     }
 
-    fn goto_implementation(&self, _: TextDocumentPositionParams) -> Self::ImplementationFuture {
-        Box::new(future::ok(None))
+    async fn goto_implementation(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<GotoImplementationResponse>> {
+        Ok(None)
     }
 
-    fn document_highlight(&self, _: TextDocumentPositionParams) -> Self::HighlightFuture {
-        Box::new(future::ok(None))
+    async fn document_highlight(
+        &self,
+        _: TextDocumentPositionParams,
+    ) -> Result<Option<Vec<DocumentHighlight>>> {
+        Ok(None)
     }
 }
 
-fn main() {
+#[tokio::main]
+async fn main() {
     env_logger::init();
 
     let stdin = tokio::io::stdin();
@@ -149,5 +157,5 @@ fn main() {
         .interleave(messages)
         .serve(service);
 
-    tokio::run(handle.run_until_exit(server));
+    handle.run_until_exit(server).await;
 }
diff --git a/src/codec.rs b/src/codec.rs
@@ -5,7 +5,8 @@ use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::io::{Error as IoError, Write};
 use std::str::{self, Utf8Error};
 
-use bytes::{BufMut, BytesMut};
+use bytes::buf::ext::BufMutExt;
+use bytes::{Buf, BytesMut};
 use nom::branch::alt;
 use nom::bytes::streaming::{is_not, tag};
 use nom::character::streaming::{char, crlf, digit1, space0};
@@ -14,7 +15,7 @@ use nom::error::ErrorKind;
 use nom::multi::length_data;
 use nom::sequence::{delimited, terminated, tuple};
 use nom::{Err, IResult, Needed};
-use tokio_codec::{Decoder, Encoder};
+use tokio_util::codec::{Decoder, Encoder};
 
 /// Errors that can occur when processing an LSP request.
 #[derive(Debug)]
@@ -155,9 +156,9 @@ mod tests {
         let mut codec = LanguageServerCodec::default();
         let mut buffer = BytesMut::new();
         codec.encode(decoded.clone(), &mut buffer).unwrap();
-        assert_eq!(buffer, BytesMut::from(encoded.clone()));
+        assert_eq!(buffer, BytesMut::from(encoded.as_str()));
 
-        let mut buffer = BytesMut::from(encoded);
+        let mut buffer = BytesMut::from(encoded.as_str());
         let message = codec.decode(&mut buffer).unwrap();
         assert_eq!(message, Some(decoded));
     }
@@ -178,7 +179,7 @@ mod tests {
         let encoded = format!("{}\r\n{}\r\n\r\n{}", content_len, content_type, decoded);
 
         let mut codec = LanguageServerCodec::default();
-        let mut buffer = BytesMut::from(encoded);
+        let mut buffer = BytesMut::from(encoded.as_str());
         let message = codec.decode(&mut buffer).unwrap();
         assert_eq!(message, Some(decoded));
     }