fix: handlers wait for buffer to be loaded (#72)

Author: stevearc

src/handles/documentSymbol.ts

@@ -6,10 +6,10 @@ import {IFunction, IIdentifier} from "../server/buffer";
 import {documents} from "../server/documents";
 import config from "../server/config";
 
-export const documentSymbolProvider = (params: DocumentSymbolParams): DocumentSymbol[] | SymbolInformation[] => {
+export const documentSymbolProvider = async (params: DocumentSymbolParams): Promise<DocumentSymbol[] | SymbolInformation[]> => {
   const documentSymbols: DocumentSymbol[] = []
   const { textDocument } = params
-  const buffer = workspace.getBufferByUri(textDocument.uri)
+  const buffer = await workspace.getBufferByUri(textDocument.uri)
   const document = documents.get(textDocument.uri)
   if (!buffer || !document) {
     return documentSymbols

src/handles/foldingRange.ts

@@ -2,10 +2,10 @@ import {FoldingRange, FoldingRangeParams} from "vscode-languageserver";
 
 import {workspace} from "../server/workspaces";
 
-export const foldingRangeProvider = (params: FoldingRangeParams) => {
+export const foldingRangeProvider = async (params: FoldingRangeParams) => {
   const res: FoldingRange[] = [];
   const { textDocument } = params;
-  const buffer = workspace.getBufferByUri(textDocument.uri);
+  const buffer = await workspace.getBufferByUri(textDocument.uri);
   if (!buffer) {
     return res;
   }

src/handles/selectionRange.ts

@@ -3,13 +3,13 @@ import {SelectionRangeParams, SelectionRange, Range, Position} from "vscode-lang
 import {workspace} from "../server/workspaces";
 import {documents} from "../server/documents";
 
-export const selectionRangeProvider = (params: SelectionRangeParams): SelectionRange[] => {
+export const selectionRangeProvider = async (params: SelectionRangeParams): Promise<SelectionRange[]> => {
   const selectRanges: SelectionRange[] = [];
   const { textDocument, positions } = params;
   if (!positions || positions.length === 0) {
     return selectRanges
   }
-  const buffer = workspace.getBufferByUri(textDocument.uri);
+  const buffer = await workspace.getBufferByUri(textDocument.uri);
   const document = documents.get(textDocument.uri)
   if (!buffer || !document) {
     return selectRanges;

src/server/workspaces.ts

@@ -11,6 +11,7 @@ import config from "./config";
 
 export class Workspace {
   private buffers: Record<string, Buffer> = {};
+  private pendingBuffers: Record<string, Promise<Buffer>> = {};
 
   public isExistsBuffer(uri: string) {
     if (this.buffers[uri]) {
@@ -26,19 +27,31 @@ export class Workspace {
     if (this.buffers[uri]) {
       this.buffers[uri].updateBufferByNode(node);
     } else {
-      let projectRoot = await findProjectRoot(
-        URI.parse(uri).fsPath,
-        config.indexes.projectRootPatterns,
-      );
-      if (config.vimruntime.trim() !== '' && projectRoot.indexOf(config.vimruntime) === 0) {
-        projectRoot = config.vimruntime;
-      }
-      this.buffers[uri] = new Buffer(uri, projectRoot, node);
+      const loadPromise = this.loadBuffer(uri, node)
+      this.pendingBuffers[uri] = loadPromise
+      this.buffers[uri] = await loadPromise
+      delete this.pendingBuffers[uri]
+    }
+  }
+
+  private async loadBuffer(uri: string, node: INode) : Promise<Buffer> {
+    let projectRoot = await findProjectRoot(
+      URI.parse(uri).fsPath,
+      config.indexes.projectRootPatterns,
+    );
+    if (config.vimruntime.trim() !== '' && projectRoot.indexOf(config.vimruntime) === 0) {
+      projectRoot = config.vimruntime;
     }
+    return new Buffer(uri, projectRoot, node);
   }
 
-  public getBufferByUri(uri: string): Buffer | undefined {
-    return this.buffers[uri];
+  public getBufferByUri(uri: string): Promise<Buffer | undefined> {
+    if (this.buffers[uri]) {
+      return Promise.resolve(this.buffers[uri])
+    } else if (this.pendingBuffers[uri]) {
+      return this.pendingBuffers[uri]
+    }
+    return Promise.resolve(undefined)
   }
 
   public getFunctionItems(uri: string) {