Fixes #41268: Do not avoid sliced strings

src/vs/editor/common/model/linesTextBuffer/linesTextBufferBuilder.ts

@@ -25,48 +25,8 @@ export class TextBufferFactory implements ITextBufferFactory {
 	}
 }
 
-const AVOID_SLICED_STRINGS = true;
-const PREALLOC_BUFFER_CHARS = 1000;
-
-const emptyString = '';
-const asciiStrings: string[] = [];
-for (let i = 0; i < 128; i++) {
-	asciiStrings[i] = String.fromCharCode(i);
-}
-
-function optimizeStringMemory(buff: Buffer, s: string): string {
-	const len = s.length;
-
-	if (len === 0) {
-		return emptyString;
-	}
-
-	if (len === 1) {
-		const charCode = s.charCodeAt(0);
-		if (charCode < 128) {
-			return asciiStrings[charCode];
-		}
-	}
-
-	if (AVOID_SLICED_STRINGS) {
-		// See https://bugs.chromium.org/p/v8/issues/detail?id=2869
-		// See https://github.com/nodejs/help/issues/711
-
-		if (len < PREALLOC_BUFFER_CHARS) {
-			// Use the same buffer instance that we have allocated and that can fit `PREALLOC_BUFFER_CHARS` characters
-			const byteLen = buff.write(s, 0);
-			return buff.toString(undefined, 0, byteLen);
-		}
-
-		return Buffer.from(s).toString();
-	}
-
-	return s;
-}
-
 class ModelLineBasedBuilder {
 
-	private buff: Buffer;
 	private BOM: string;
 	private lines: string[];
 	private currLineIndex: number;
@@ -75,7 +35,6 @@ class ModelLineBasedBuilder {
 		this.BOM = '';
 		this.lines = [];
 		this.currLineIndex = 0;
-		this.buff = Buffer.alloc(3/*any UTF16 code unit could expand to up to 3 UTF8 code units*/ * PREALLOC_BUFFER_CHARS);
 	}
 
 	public acceptLines(lines: string[]): void {
@@ -88,7 +47,7 @@ class ModelLineBasedBuilder {
 		}
 
 		for (let i = 0, len = lines.length; i < len; i++) {
-			this.lines[this.currLineIndex++] = optimizeStringMemory(this.buff, lines[i]);
+			this.lines[this.currLineIndex++] = lines[i];
 		}
 	}