From bb68ebb921bd77abee3fea7e521aa7aa776e90f6 Mon Sep 17 00:00:00 2001
From: Eric Traut <erictr@microsoft.com>
Date: Sun, 17 Nov 2019 20:51:04 -0800
Subject: [PATCH] Removed CancelToken and its use in parser. It's not used, so
 it's just overhead.

---
 server/src/common/cancelToken.ts | 30 ------------------------------
 server/src/common/timing.ts      |  4 ----
 server/src/parser/parser.ts      | 21 +++------------------
 server/src/tests/parser.test.ts  |  3 ++-
 4 files changed, 5 insertions(+), 53 deletions(-)
 delete mode 100644 server/src/common/cancelToken.ts

diff --git a/server/src/common/cancelToken.ts b/server/src/common/cancelToken.ts
deleted file mode 100644
index 4c19e27f8..000000000
--- a/server/src/common/cancelToken.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
-* cancelToken.ts
-* Copyright (c) Microsoft Corporation.
-* Licensed under the MIT license.
-* Author: Eric Traut
-*
-* A simple class that allows a caller to cancel an async operation.
-* The async operation needs to cooperatively check for cancellation.
-*/
-
-export class CancelError extends Error {
-}
-
-export class CancelToken {
-    private _isCanceled = false;
-
-    cancel(): void {
-        this._isCanceled = true;
-    }
-
-    isCanceled(): boolean {
-        return this._isCanceled;
-    }
-
-    throwIfCanceled(): void {
-        if (this._isCanceled) {
-            throw new CancelError();
-        }
-    }
-}
diff --git a/server/src/common/timing.ts b/server/src/common/timing.ts
index dcf2e45d3..b69468d71 100644
--- a/server/src/common/timing.ts
+++ b/server/src/common/timing.ts
@@ -17,10 +17,6 @@ export class Duration {
         this._startTime = Date.now();
     }
 
-    restart() {
-        this._startTime = Date.now();
-    }
-
     getDurationInMilliseconds() {
         const curTime = Date.now();
         return curTime - this._startTime;
diff --git a/server/src/parser/parser.ts b/server/src/parser/parser.ts
index 6d063978b..9364e3f68 100644
--- a/server/src/parser/parser.ts
+++ b/server/src/parser/parser.ts
@@ -13,7 +13,6 @@
 
 import * as assert from 'assert';
 
-import { CancelToken } from '../common/cancelToken';
 import { Diagnostic } from '../common/diagnostic';
 import { DiagnosticSink } from '../common/diagnosticSink';
 import { convertOffsetsToRange, convertPositionToOffset } from '../common/positionUtils';
@@ -86,7 +85,6 @@ export class Parser {
     private _tokenizerOutput?: TokenizerOutput;
     private _tokenIndex = 0;
     private _parseOptions: ParseOptions = new ParseOptions();
-    private _cancelToken?: CancelToken;
     private _diagSink: DiagnosticSink = new DiagnosticSink();
     private _isInLoop = false;
     private _isInFinally = false;
@@ -96,11 +94,11 @@ export class Parser {
     private _containsWildcardImport = false;
 
     parseSourceFile(fileContents: string, parseOptions: ParseOptions,
-            diagSink: DiagnosticSink, cancelToken?: CancelToken): ParseResults {
+            diagSink: DiagnosticSink): ParseResults {
 
         timingStats.tokenizeFileTime.timeOperation(() => {
             this._startNewParse(fileContents, 0, fileContents.length,
-                parseOptions, diagSink, cancelToken);
+                parseOptions, diagSink);
         });
 
         const moduleNode = ModuleNode.create({ start: 0, length: fileContents.length });
@@ -124,8 +122,6 @@ export class Parser {
                         statement.parent = moduleNode;
                         moduleNode.statements.push(statement);
                     }
-
-                    this._checkCancel();
                 }
             }
         });
@@ -164,20 +160,15 @@ export class Parser {
     }
 
     private _startNewParse(fileContents: string, textOffset: number, textLength: number,
-            parseOptions: ParseOptions, diagSink: DiagnosticSink, cancelToken?: CancelToken) {
+            parseOptions: ParseOptions, diagSink: DiagnosticSink) {
         this._fileContents = fileContents;
         this._parseOptions = parseOptions;
-        this._cancelToken = cancelToken;
         this._diagSink = diagSink;
 
-        this._checkCancel();
-
         // Tokenize the file contents.
         const tokenizer = new Tokenizer();
         this._tokenizerOutput = tokenizer.tokenize(fileContents, textOffset, textLength);
         this._tokenIndex = 0;
-
-        this._checkCancel();
     }
 
     // stmt: simple_stmt | compound_stmt
@@ -2837,12 +2828,6 @@ export class Parser {
         return false;
     }
 
-    private _checkCancel() {
-        if (this._cancelToken) {
-            this._cancelToken.throwIfCanceled();
-        }
-    }
-
     private _getNextToken(): Token {
         const token = this._tokenizerOutput!.tokens.getItemAt(this._tokenIndex);
         if (!this._atEof()) {
diff --git a/server/src/tests/parser.test.ts b/server/src/tests/parser.test.ts
index 5df3554ba..0ed77456a 100644
--- a/server/src/tests/parser.test.ts
+++ b/server/src/tests/parser.test.ts
@@ -4,7 +4,8 @@
 * Licensed under the MIT license.
 * Author: Eric Traut
 *
-* Unit tests for Python parser.
+* Unit tests for Python parser. These are very basic because
+* the parser gets lots of exercise in the type checker tests.
 */
 
 import * as assert from 'assert';