wip: Async async. Delay response handling with a callback.

Cargo.lock

@@ -549,6 +549,8 @@ dependencies = [
  "num_cpus",
  "once_cell",
  "pulldown-cmark",
+ "serde",
+ "serde_json",
  "smol",
  "smol-timeout",
  "toml",

helix-lsp/src/client.rs

@@ -1,13 +1,12 @@
 use crate::{
     transport::{Payload, Transport},
-    Call, Error,
+    Call, Error, Result,
 };
 
-type Result<T> = core::result::Result<T, Error>;
-
 use helix_core::{ChangeSet, Rope};
 
 // use std::collections::HashMap;
+use std::future::Future;
 use std::sync::atomic::{AtomicU64, Ordering};
 
 use jsonrpc_core as jsonrpc;
@@ -96,6 +95,21 @@ impl Client {
     where
         R::Params: serde::Serialize,
         R::Result: core::fmt::Debug, // TODO: temporary
+    {
+        // a future that resolves into the response
+        let future = self.call::<R>(params).await?;
+        let json = future.await?;
+        let response = serde_json::from_value(json)?;
+        Ok(response)
+    }
+
+    /// Execute a RPC request on the language server.
+    pub async fn call<R: lsp::request::Request>(
+        &self,
+        params: R::Params,
+    ) -> Result<impl Future<Output = Result<Value>>>
+    where
+        R::Params: serde::Serialize,
     {
         let params = serde_json::to_value(params)?;
 
@@ -119,15 +133,15 @@ impl Client {
         use smol_timeout::TimeoutExt;
         use std::time::Duration;
 
-        let response = match rx.recv().timeout(Duration::from_secs(2)).await {
-            Some(response) => response,
-            None => return Err(Error::Timeout),
-        }
-        .map_err(|e| Error::Other(e.into()))??;
-
-        let response = serde_json::from_value(response)?;
+        let future = async move {
+            rx.recv()
+                .timeout(Duration::from_secs(2))
+                .await
+                .ok_or(Error::Timeout)? // return Timeout
+                .map_err(|e| Error::Other(e.into()))?
+        };
 
-        Ok(response)
+        Ok(future)
     }
 
     /// Send a RPC notification to the language server.
@@ -447,7 +461,8 @@ impl Client {
         &self,
         text_document: lsp::TextDocumentIdentifier,
         position: lsp::Position,
-    ) -> Result<Vec<lsp::CompletionItem>> {
+    ) -> Result<impl Future<Output = Result<Value>>> {
+        // ) -> Result<Vec<lsp::CompletionItem>> {
         let params = lsp::CompletionParams {
             text_document_position: lsp::TextDocumentPositionParams {
                 text_document,
@@ -464,19 +479,7 @@ impl Client {
             // lsp::CompletionContext { trigger_kind: , trigger_character: Some(), }
         };
 
-        let response = self.request::<lsp::request::Completion>(params).await?;
-
-        let items = match response {
-            Some(lsp::CompletionResponse::Array(items)) => items,
-            // TODO: do something with is_incomplete
-            Some(lsp::CompletionResponse::List(lsp::CompletionList {
-                is_incomplete: _is_incomplete,
-                items,
-            })) => items,
-            None => Vec::new(),
-        };
-
-        Ok(items)
+        self.call::<lsp::request::Completion>(params).await
     }
 
     pub async fn text_document_signature_help(

helix-lsp/src/lib.rs

@@ -8,6 +8,8 @@ pub use lsp_types as lsp;
 pub use client::Client;
 pub use lsp::{Position, Url};
 
+pub type Result<T> = core::result::Result<T, Error>;
+
 use helix_core::syntax::LanguageConfiguration;
 
 use thiserror::Error;

helix-term/Cargo.toml

@@ -44,3 +44,6 @@ pulldown-cmark = { version = "0.8", default-features = false }
 
 # config
 toml = "0.5"
+
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }

helix-term/src/application.rs

@@ -24,11 +24,23 @@ use crossterm::{
 
 use tui::layout::Rect;
 
+// use futures_util::future::BoxFuture;
+use futures_util::stream::FuturesUnordered;
+use std::pin::Pin;
+
+type BoxFuture<T> = Pin<Box<dyn Future<Output = T> + Send>>;
+pub type LspCallback =
+    BoxFuture<Result<Box<dyn FnOnce(&mut Editor, &mut Compositor) + Send>, anyhow::Error>>;
+
+pub type LspCallbacks = FuturesUnordered<LspCallback>;
+pub type LspCallbackWrapper = Box<dyn FnOnce(&mut Editor, &mut Compositor) + Send>;
+
 pub struct Application {
     compositor: Compositor,
     editor: Editor,
 
     executor: &'static smol::Executor<'static>,
+    callbacks: LspCallbacks,
 }
 
 impl Application {
@@ -50,6 +62,7 @@ impl Application {
             editor,
 
             executor,
+            callbacks: FuturesUnordered::new(),
         };
 
         Ok(app)
@@ -59,10 +72,12 @@ impl Application {
         let executor = &self.executor;
         let editor = &mut self.editor;
         let compositor = &mut self.compositor;
+        let callbacks = &mut self.callbacks;
 
         let mut cx = crate::compositor::Context {
             editor,
             executor,
+            callbacks,
             scroll: None,
         };
 
@@ -87,14 +102,28 @@ impl Application {
                 call = self.editor.language_servers.incoming.next().fuse() => {
                     self.handle_language_server_message(call).await
                 }
+                callback = self.callbacks.next().fuse() => {
+                    self.handle_language_server_callback(callback)
+                }
             }
         }
     }
+    pub fn handle_language_server_callback(
+        &mut self,
+        callback: Option<Result<LspCallbackWrapper, anyhow::Error>>,
+    ) {
+        if let Some(Ok(callback)) = callback {
+            // TODO: handle Err()
+            callback(&mut self.editor, &mut self.compositor);
+            self.render();
+        }
+    }
 
     pub fn handle_terminal_events(&mut self, event: Option<Result<Event, crossterm::ErrorKind>>) {
         let mut cx = crate::compositor::Context {
             editor: &mut self.editor,
             executor: &self.executor,
+            callbacks: &mut self.callbacks,
             scroll: None,
         };
         // Handle key events

helix-term/src/commands.rs

@@ -10,7 +10,7 @@ use helix_core::{
 use once_cell::sync::Lazy;
 
 use crate::{
-    compositor::{Callback, Compositor},
+    compositor::{Callback, Component, Compositor},
     ui::{self, Picker, Popup, Prompt, PromptEvent},
 };
 
@@ -26,14 +26,20 @@ use crossterm::event::{KeyCode, KeyEvent};
 
 use helix_lsp::lsp;
 
+use crate::application::{LspCallbackWrapper, LspCallbacks};
+
 pub struct Context<'a> {
     pub count: usize,
     pub editor: &'a mut Editor,
 
     pub callback: Option<crate::compositor::Callback>,
     pub on_next_key_callback: Option<Box<dyn FnOnce(&mut Context, KeyEvent)>>,
+    pub callbacks: &'a mut LspCallbacks,
 }
 
+use futures_util::FutureExt;
+use std::future::Future;
+
 impl<'a> Context<'a> {
     #[inline]
     pub fn view(&mut self) -> &mut View {
@@ -47,7 +53,7 @@ impl<'a> Context<'a> {
     }
 
     /// Push a new component onto the compositor.
-    pub fn push_layer(&mut self, mut component: Box<dyn crate::compositor::Component>) {
+    pub fn push_layer(&mut self, mut component: Box<dyn Component>) {
         self.callback = Some(Box::new(
             |compositor: &mut Compositor, editor: &mut Editor| {
                 let size = compositor.size();
@@ -65,6 +71,27 @@ impl<'a> Context<'a> {
     ) {
         self.on_next_key_callback = Some(Box::new(on_next_key_callback));
     }
+
+    #[inline]
+    pub fn callback<T, F>(
+        &mut self,
+        call: impl Future<Output = helix_lsp::Result<serde_json::Value>> + 'static + Send,
+        callback: F,
+    ) where
+        T: for<'de> serde::Deserialize<'de> + Send + 'static,
+        F: FnOnce(&mut Editor, &mut Compositor, T) + Send + 'static,
+    {
+        let callback = Box::pin(async move {
+            let json = call.await?;
+            let response = serde_json::from_value(json)?;
+            let call: LspCallbackWrapper =
+                Box::new(move |editor: &mut Editor, compositor: &mut Compositor| {
+                    callback(editor, compositor, response)
+                });
+            Ok(call)
+        });
+        self.callbacks.push(callback);
+    }
 }
 
 /// A command is a function that takes the current state and a count, and does a side-effect on the
@@ -1564,6 +1591,24 @@ pub fn save(cx: &mut Context) {
 }
 
 pub fn completion(cx: &mut Context) {
+    // trigger on trigger char, or if user calls it
+    // (or on word char typing??)
+    // after it's triggered, if response marked is_incomplete, update on every subsequent keypress
+    //
+    // lsp calls are done via a callback: it sends a request and doesn't block.
+    // when we get the response similarly to notification, trigger a call to the completion popup
+    //
+    // language_server.completion(params, |cx: &mut Context, _meta, response| {
+    //    // called at response time
+    //    // compositor, lookup completion layer
+    //    // downcast dyn Component to Completion component
+    //    // emit response to completion (completion.complete/handle(response))
+    // })
+    // async {
+    //    let (response, callback) = response.await?;
+    //    callback(response)
+    // }
+
     let doc = cx.doc();
 
     let language_server = match doc.language_server() {
@@ -1576,13 +1621,28 @@ pub fn completion(cx: &mut Context) {
 
     // TODO: handle fails
 
-    let res = smol::block_on(language_server.completion(doc.identifier(), pos)).unwrap_or_default();
+    let res = smol::block_on(language_server.completion(doc.identifier(), pos)).unwrap();
+
+    cx.callback(
+        res,
+        |editor: &mut Editor,
+         compositor: &mut Compositor,
+         response: Option<lsp::CompletionResponse>| {
+            let items = match response {
+                Some(lsp::CompletionResponse::Array(items)) => items,
+                // TODO: do something with is_incomplete
+                Some(lsp::CompletionResponse::List(lsp::CompletionList {
+                    is_incomplete: _is_incomplete,
+                    items,
+                })) => items,
+                None => Vec::new(),
+            };
 
             // TODO: if no completion, show some message or something
-    if !res.is_empty() {
+            if !items.is_empty() {
                 // let snapshot = doc.state.clone();
                 let mut menu = ui::Menu::new(
-            res,
+                    items,
                     |item| {
                         // format_fn
                         item.label.as_str().into()
@@ -1623,7 +1683,10 @@ pub fn completion(cx: &mut Context) {
                                     match edit {
                                         lsp::CompletionTextEdit::Edit(edit) => edit.clone(),
                                         lsp::CompletionTextEdit::InsertAndReplace(item) => {
-                                    unimplemented!("completion: insert_and_replace {:?}", item)
+                                            unimplemented!(
+                                                "completion: insert_and_replace {:?}",
+                                                item
+                                            )
                                         }
                                     }
                                 } else {
@@ -1643,7 +1706,6 @@ pub fn completion(cx: &mut Context) {
                                     }
                                 }
 
-                        // TODO: <-- if state has changed by further input, transaction will panic on len
                                 let transaction =
                                     util::generate_transaction_from_edits(doc.text(), vec![edit]);
                                 doc.apply(&transaction);
@@ -1655,12 +1717,23 @@ pub fn completion(cx: &mut Context) {
                 );
 
                 let popup = Popup::new(Box::new(menu));
-        cx.push_layer(Box::new(popup));
+                let mut component: Box<dyn Component> = Box::new(popup);
 
-        // TODO!: when iterating over items, show the docs in popup
+                //  Server error: content modified
 
-        // language server client needs to be accessible via a registry of some sort
+                // TODO: this is shared with cx.push_layer
+                let size = compositor.size();
+                // trigger required_size on init
+                component.required_size((size.width, size.height));
+                compositor.push(component);
             }
+        },
+    );
+
+    //    // TODO!: when iterating over items, show the docs in popup
+
+    //    // language server client needs to be accessible via a registry of some sort
+    //}
 }
 
 pub fn hover(cx: &mut Context) {

helix-term/src/compositor.rs

@@ -25,10 +25,13 @@ pub enum EventResult {
 
 use helix_view::{Editor, View};
 
+use crate::application::LspCallbacks;
+
 pub struct Context<'a> {
     pub editor: &'a mut Editor,
     pub executor: &'static smol::Executor<'static>,
     pub scroll: Option<usize>,
+    pub callbacks: &'a mut LspCallbacks,
 }
 
 pub trait Component {

helix-term/src/ui/editor.rs

@@ -439,6 +439,7 @@ impl Component for EditorView {
                     editor: &mut cx.editor,
                     count: 1,
                     callback: None,
+                    callbacks: cx.callbacks,
                     on_next_key_callback: None,
                 };