[WIP] Autocomplete

Cargo.toml

@@ -15,4 +15,4 @@ log = "*"
 lazy_static = "1.3.0"
 lsp-types = { version = "0.61.0", features = ["proposed"] }
 simple-logging = "*"
-url = "*"
+url = {version = "2.0.0", features = ["serde"]}

autoload/lspc.vim

@@ -88,6 +88,13 @@ function! lspc#format_doc()
   call rpcnotify(s:job_id, 'format_doc', l:lang_id, l:cur_path, l:lines)
 endfunction
 
+function! lspc#completion()
+  let l:lang_id = 'rust'
+  let l:cur_path = lspc#buffer#filename()
+  let l:position = lspc#buffer#position()
+  call rpcnotify(s:job_id, 'completion', l:lang_id, l:cur_path, l:position, 1)
+endfunction
+
 function! lspc#hello_from_the_other_side()
   call rpcnotify(s:job_id, 'hello')
 endfunction

src/lspc.rs

@@ -2,7 +2,6 @@ pub mod handler;
 // Custom LSP types
 pub mod msg;
 pub mod types;
-
 use std::{
     collections::HashMap,
     io,
@@ -12,11 +11,15 @@ use std::{
 
 use crossbeam::channel::{tick, Receiver, Select};
 use lsp_types::{
+    notification::ShowMessage,
+    request::{
+        Completion, Formatting, GotoDefinition, GotoDefinitionResponse, HoverRequest, Initialize,
+    },
+    CompletionContext, CompletionItem, CompletionParams, CompletionResponse, CompletionTriggerKind,
     self as lsp,
     notification::{self as noti},
-    request::{Formatting, GotoDefinition, GotoDefinitionResponse, HoverRequest, Initialize},
     DocumentFormattingParams, FormattingOptions, Hover, Location, Position, ShowMessageParams,
-    TextDocumentIdentifier, TextEdit,
+    TextDocumentIdentifier, TextDocumentPositionParams, TextEdit,
 };
 use serde::{Deserialize, Serialize};
 use url::Url;
@@ -67,6 +70,13 @@ pub enum Event<B: BufferId> {
         text_document_lines: Vec<String>,
         text_document: TextDocumentIdentifier,
     },
+    RequestCompletion {
+        lang_id: String,
+        text_document: TextDocumentIdentifier,
+        position: Position,
+        trigger_kind: CompletionTriggerKind,
+        trigger_character: Option<String>,
+    },
     DidOpen {
         buf_id: B,
         text_document: TextDocumentIdentifier,
@@ -176,6 +186,11 @@ pub trait Editor: 'static {
     fn show_message(&mut self, show_message_params: &ShowMessageParams) -> Result<(), EditorError>;
     fn goto(&mut self, location: &Location) -> Result<(), EditorError>;
     fn apply_edits(&self, lines: &Vec<String>, edits: &Vec<TextEdit>) -> Result<(), EditorError>;
+    fn show_completions(
+        &self,
+        column: u64,
+        completion_items: &Vec<CompletionItem>,
+    ) -> Result<(), EditorError>;
     fn watch_file_events(
         &mut self,
         text_document: &TextDocumentIdentifier,
@@ -522,6 +537,44 @@ impl<E: Editor> Lspc<E> {
                     }),
                 )?;
             }
+            Event::RequestCompletion {
+                lang_id,
+                text_document,
+                position,
+                trigger_kind,
+                trigger_character,
+            } => {
+                let handler = self.handler_for(&lang_id).ok_or(LspcError::NotStarted)?;
+                let text_document_position = TextDocumentPositionParams {
+                    text_document,
+                    position,
+                };
+                let context = Some(CompletionContext {
+                    trigger_kind,
+                    trigger_character,
+                });
+                let params = CompletionParams {
+                    text_document_position,
+                    context,
+                };
+                handler.lsp_request::<Completion>(
+                    params,
+                    Box::new(move |editor: &mut E, _handler, response| {
+                        if let Some(completion_list) = response {
+                            match completion_list {
+                                CompletionResponse::Array(items) => {
+                                    editor.show_completions(position.character, &items)?;
+                                }
+                                CompletionResponse::List(list) => {
+                                    editor.show_completions(position.character, &list.items)?;
+                                }
+                            }
+                        }
+
+                        Ok(())
+                    }),
+                )?;
+            }
             Event::DidOpen {
                 buf_id,
                 text_document,

src/neovim.rs

@@ -11,7 +11,7 @@ use std::{
 use crossbeam::channel::{self, Receiver, Sender};
 
 use lsp_types::{
-    self as lsp, GotoCapability, Hover, HoverCapability, HoverContents, Location, MarkedString,
+    self as lsp, CompletionItem, CompletionTriggerKind, GotoCapability, Hover, HoverCapability, HoverContents, Location, MarkedString,
     MarkupContent, MarkupKind, Position, ShowMessageParams, TextDocumentClientCapabilities,
     TextDocumentIdentifier, TextEdit,
 };
@@ -245,6 +245,28 @@ fn to_event(msg: NvimMessage) -> Result<Event<BufferHandler>, EditorError> {
                     text_document: format_doc_params.1,
                     text_document_lines: format_doc_params.2,
                 })
+            } else if method == "completion" {
+                #[derive(Deserialize)]
+                struct CompletionParams(
+                    String,
+                    #[serde(deserialize_with = "text_document_from_path_str")]
+                    TextDocumentIdentifier,
+                    Position,
+                    CompletionTriggerKind,
+                    #[serde(default)] Option<String>,
+                );
+
+                let completion_params: CompletionParams =
+                    Deserialize::deserialize(Value::from(params))
+                        .map_err(|_e| EditorError::Parse("failed to parse completion params"))?;
+
+                Ok(Event::RequestCompletion {
+                    lang_id: completion_params.0,
+                    text_document: completion_params.1,
+                    position: completion_params.2,
+                    trigger_kind: completion_params.3,
+                    trigger_character: completion_params.4,
+                })
             } else if method == "did_open" {
                 #[derive(Deserialize)]
                 struct DidOpenParams(
@@ -635,6 +657,26 @@ impl Editor for Neovim {
 
         Ok(())
     }
+
+    fn show_completions(
+        &self,
+        column: u64,
+        completion_items: &Vec<CompletionItem>,
+    ) -> Result<(), EditorError> {
+        let mut vim_complete_items = vec![];
+        for item in completion_items {
+            vim_complete_items.push(Value::Map(vec![
+                ("icase".into(), 1.into()),
+                ("word".into(), item.label.clone().into()),
+                ("abbr".into(), item.label.clone().into()),
+            ]));
+        }
+        self.call_function(
+            "complete",
+            Value::Array(vec![column.into(), Value::Array(vim_complete_items)]),
+        )?;
+        Ok(())
+    }
 }
 
 impl Message for NvimMessage {