Support all text document operations (#1474)

Author: msujew

packages/langium/src/lsp/document-update-handler.ts

@@ -4,7 +4,8 @@
  * terms of the MIT License, which is available in the project root.
  ******************************************************************************/
 
-import { DidChangeWatchedFilesNotification, FileChangeType, type DidChangeWatchedFilesParams, type DidChangeWatchedFilesRegistrationOptions, type TextDocumentChangeEvent } from 'vscode-languageserver';
+import type { TextDocumentWillSaveEvent, DidChangeWatchedFilesParams, DidChangeWatchedFilesRegistrationOptions, TextDocumentChangeEvent, TextEdit } from 'vscode-languageserver';
+import { DidChangeWatchedFilesNotification, FileChangeType } from 'vscode-languageserver';
 import { stream } from '../utils/stream.js';
 import { URI } from '../utils/uri-utils.js';
 import type { DocumentBuilder } from '../workspace/document-builder.js';
@@ -13,21 +14,32 @@ import type { WorkspaceLock } from '../workspace/workspace-lock.js';
 import type { LangiumSharedServices } from './lsp-services.js';
 import type { WorkspaceManager } from '../workspace/workspace-manager.js';
 import type { ServiceRegistry } from '../service-registry.js';
+import type { MaybePromise } from '../utils/promise-utils.js';
 
 /**
  * Shared service for handling text document changes and watching relevant files.
  */
 export interface DocumentUpdateHandler {
 
+    didOpenDocument?(event: TextDocumentChangeEvent<TextDocument>): void;
+
     /**
      * A content change event was triggered by the `TextDocuments` service.
      */
-    didChangeContent(change: TextDocumentChangeEvent<TextDocument>): void;
+    didChangeContent?(event: TextDocumentChangeEvent<TextDocument>): void;
+
+    willSaveDocument?(event: TextDocumentWillSaveEvent<TextDocument>): void;
+
+    willSaveDocumentWaitUntil?(event: TextDocumentWillSaveEvent<TextDocument>): MaybePromise<TextEdit[]>;
+
+    didSaveDocument?(event: TextDocumentChangeEvent<TextDocument>): void;
+
+    didCloseDocument?(event: TextDocumentChangeEvent<TextDocument>): void;
 
     /**
      * The client detected changes to files and folders watched by the language client.
      */
-    didChangeWatchedFiles(params: DidChangeWatchedFilesParams): void;
+    didChangeWatchedFiles?(params: DidChangeWatchedFilesParams): void;
 
 }
 

packages/langium/src/lsp/language-server.ts

@@ -98,6 +98,7 @@ export class DefaultLanguageServer implements LanguageServer {
     }
 
     protected buildInitializeResult(_params: InitializeParams): InitializeResult {
+        const documentUpdateHandler = this.services.lsp.DocumentUpdateHandler;
         const fileOperationOptions = this.services.lsp.FileOperationHandler?.fileOperationOptions;
         const allServices: readonly LangiumCoreAndPartialLSPServices[] = this.services.ServiceRegistry.all;
         const hasFormattingService = this.hasService(e => e.lsp?.Formatter);
@@ -136,7 +137,13 @@ export class DefaultLanguageServer implements LanguageServer {
                 executeCommandProvider: commandNames && {
                     commands: commandNames
                 },
-                textDocumentSync: TextDocumentSyncKind.Incremental,
+                textDocumentSync: {
+                    change: TextDocumentSyncKind.Incremental,
+                    openClose: true,
+                    save: Boolean(documentUpdateHandler.didSaveDocument),
+                    willSave: Boolean(documentUpdateHandler.willSaveDocument),
+                    willSaveWaitUntil: Boolean(documentUpdateHandler.willSaveDocumentWaitUntil)
+                },
                 completionProvider: hasCompletionProvider ? completionOptions : undefined,
                 referencesProvider: hasReferencesProvider,
                 documentSymbolProvider: hasDocumentSymbolProvider,
@@ -267,8 +274,27 @@ export function startLanguageServer(services: LangiumSharedServices): void {
 export function addDocumentUpdateHandler(connection: Connection, services: LangiumSharedServices): void {
     const handler = services.lsp.DocumentUpdateHandler;
     const documents = services.workspace.TextDocuments;
-    documents.onDidChangeContent(change => handler.didChangeContent(change));
-    connection.onDidChangeWatchedFiles(params => handler.didChangeWatchedFiles(params));
+    if (handler.didOpenDocument) {
+        documents.onDidOpen(change => handler.didOpenDocument!(change));
+    }
+    if (handler.didChangeContent) {
+        documents.onDidChangeContent(change => handler.didChangeContent!(change));
+    }
+    if (handler.didCloseDocument) {
+        documents.onDidClose(change => handler.didCloseDocument!(change));
+    }
+    if (handler.didSaveDocument) {
+        documents.onDidSave(change => handler.didSaveDocument!(change));
+    }
+    if (handler.willSaveDocument) {
+        documents.onWillSave(event => handler.willSaveDocument!(event));
+    }
+    if (handler.willSaveDocumentWaitUntil) {
+        documents.onWillSaveWaitUntil(event => handler.willSaveDocumentWaitUntil!(event));
+    }
+    if (handler.didChangeWatchedFiles) {
+        connection.onDidChangeWatchedFiles(params => handler.didChangeWatchedFiles!(params));
+    }
 }
 
 export function addFileOperationHandler(connection: Connection, services: LangiumSharedServices): void {