Merge pull request #21 from SSlinky/dev

Better error handling and parse cancellation

Author: SSlinky

package-lock.json

@@ -6,7 +6,7 @@
 	"icon": "images/vba-lsp-icon.png",
 	"author": "SSlinky",
 	"license": "MIT",
-	"version": "1.4.3",
+	"version": "1.4.4",
 	"repository": {
 		"type": "git",
 		"url": "https://github.com/SSlinky/VBA-LanguageServer"

package.json

@@ -6,6 +6,7 @@ import { Range, TextDocument } from 'vscode-languageserver-textdocument';
 import { SyntaxParser } from './parser/vbaSyntaxParser';
 import { FoldingRange } from '../capabilities/folding';
 import { SemanticTokensManager } from '../capabilities/semanticTokens';
+import { ParseCancellationException } from 'antlr4ng';
 
 export interface DocumentSettings {
 	maxDocumentLines: number;
@@ -134,13 +135,28 @@ export abstract class BaseProjectDocument {
 	}
 
 	async parseAsync(token: CancellationToken): Promise<void> {
+		// Handle already cancelled.
+		if (token.isCancellationRequested) {
+			throw new ParseCancellationException(Error('Parse operation cancelled before it started.'));
+		}
+
+		// Listen for cancellation event.
+		token.onCancellationRequested(() => {
+			throw new ParseCancellationException(new Error('Parse operation cancelled during parse.'));
+		})
+
+		// Don't parse oversize documents.
 		if (await this.isOversize) {
 			console.log(`Document oversize: ${this.textDocument.lineCount} lines.`);
             console.warn(`Syntax parsing has been disabled to prevent crashing.`);
 			this._isBusy = false;
 			return;
 		}
+
+		// Parse the document.
 		await (new SyntaxParser()).parseAsync(this, token)
+
+		// Evaluate the diagnostics.
 		this._hasDiagnosticElements.forEach(element => {
 			element.evaluateDiagnostics;
 			this._diagnostics.concat(element.diagnostics);

server/src/project/document.ts

@@ -48,7 +48,14 @@ export class Workspace {
 		this.activateDocument(document);
 		this._parseCancellationTokenSource?.cancel();
 		this._parseCancellationTokenSource = new CancellationTokenSource();
-		await this._activeDocument?.parseAsync(this._parseCancellationTokenSource.token);
+
+		// Exceptions thrown by the parser should be ignored.
+		try {
+			await this._activeDocument?.parseAsync(this._parseCancellationTokenSource.token);
+		} catch (error) {
+			this.connection.console.log(`Parser error: ${error}`)
+		}
+
 		this._parseCancellationTokenSource = undefined;
 		this.connection.sendDiagnostics(this._activeDocument?.languageServerDiagnostics() ?? {uri: "", diagnostics: []});
 	}

server/src/project/workspace.ts

@@ -69,7 +69,7 @@
 		"prefix": "func",
 		"description": "Function",
 		"body": [
-			"${1:Public }Function ${2:Identifier}($3) As $4",
+			"${1:Public }Function ${2:Identifier}($3) As ${4:Variant}",
 			"Attribute $2.VB_Description = \"${5:Dosctring}.\"",
 			"'   $5.",
 			"'",