implement async completion

autoload/ddc_vim_lsp.vim

@@ -1,6 +1,5 @@
-function! ddc_vim_lsp#_callback(server, position, plugin_name, method_name, data) abort
+function! ddc_vim_lsp#_callback(server, position, data) abort
   if lsp#client#is_error(a:data) || !has_key(a:data, 'response') || !has_key(a:data['response'], 'result')
-    call denops#request(a:plugin_name, a:method_name, [])
     return
   endif
 
@@ -10,10 +9,16 @@ function! ddc_vim_lsp#_callback(server, position, plugin_name, method_name, data
       \ 'response': a:data['response'],
       \ }
   let lspitems = lsp#omni#get_vim_completion_items(l:options)['items']
-  call denops#request(a:plugin_name, a:method_name, [lspitems])
+ 
+  if len(lspitems) > 0
+    let g:ddc#source#ddc_vim_lsp#_results = lspitems
+    let g:ddc#source#ddc_vim_lsp#_requested = v:true
+
+    call ddc#refresh_candidates()
+  endif
 endfunction
 
-function! ddc_vim_lsp#request(server_name, plugin_name, method_name) abort
+function! ddc_vim_lsp#request(server_name) abort
   let l:server = lsp#get_server_info(a:server_name)
   let l:position = lsp#get_position()
 
@@ -23,6 +28,6 @@ function! ddc_vim_lsp#request(server_name, plugin_name, method_name) abort
     \   'textDocument': lsp#get_text_document_identifier(),
     \   'position': l:position,
     \ },
-    \ 'on_notification': function('ddc_vim_lsp#_callback', [l:server, l:position, a:plugin_name, a:method_name]),
+    \ 'on_notification': function('ddc_vim_lsp#_callback', [l:server, l:position]),
     \ })
 endfunction

denops/ddc-sources/ddc-vim-lsp.ts

@@ -4,7 +4,9 @@ import {
 } from "https://deno.land/x/ddc_vim@v0.4.2/types.ts#^";
 
 import {
+  batch,
   Denops,
+  vars,
 } from "https://deno.land/x/ddc_vim@v0.4.2/deps.ts#^";
 
 import {
@@ -12,25 +14,41 @@ import {
 } from "https://deno.land/x/denops_std@v1.8.1/anonymous/mod.ts";
 
 export class Source extends BaseSource {
+  async onInit(args: {
+    denops: Denops,
+  }): Promise<void> {
+    await batch(args.denops, async (denops) => {
+      vars.g.set(denops, "ddc#source#ddc_vim_lsp#_results", []);
+      vars.g.set(denops, "ddc#source#ddc_vim_lsp#_requested", false);
+      vars.g.set(denops, "ddc#source#ddc_vim_lsp#_prev_input", "");
+    });
+  }
+
   async gatherCandidates(args: {
     denops: Denops,
     context: Context,
     completeStr: string,
   }): Promise<Candidate[]> {
+    const prevInput = await vars.g.get(args.denops, "ddc#source#ddc_vim_lsp#_prev_input");
+    const requested = await vars.g.get(args.denops, "ddc#source#ddc_vim_lsp#_requested");
+    if (args.context.input == prevInput && requested) {
+      return await vars.g.get(args.denops, "ddc#source#ddc_vim_lsp#_results");
+    }
 
     const lspservers = await args.denops.call("lsp#get_allowed_servers");
     if (lspservers.length === 0) {
       return [];
     }
 
-    return new Promise((resolve) => {
+    await batch(args.denops, async (denops) => {
+      vars.g.set(denops, "ddc#source#ddc_vim_lsp#_results", []);
+      vars.g.set(denops, "ddc#source#ddc_vim_lsp#_requested", false);
+      vars.g.set(denops, "ddc#source#ddc_vim_lsp#_prev_input", args.context.input);
+
       // NOTE: choose first lsp server
-      args.denops.call("ddc_vim_lsp#request", lspservers[0], args.denops.name, once(args.denops, (response) => {
-        resolve(response);
-      })[0])
-    })
-    .then((cs: Candidate[]) => {
-      return cs;
+      denops.call("ddc_vim_lsp#request", lspservers[0]);
     });
+
+    return [];
   }
 }