Class MutableDisposable

src/vs/base/common/lifecycle.ts:507–557

 * also register a `MutableDisposable` on a `Disposable` to ensure it is automatically cleaned up.
 */
export class MutableDisposable<T extends IDisposable> implements IDisposable {
	private _value?: T;
	private _isDisposed = false;

	constructor() {
		trackDisposable(this);
	}

	get value(): T | undefined {
		return this._isDisposed ? undefined : this._value;
	}

	set value(value: T | undefined) {
		if (this._isDisposed || value === this._value) {
			return;
		}

		this._value?.dispose();
		if (value) {
			setParentOfDisposable(value, this);
		}
		this._value = value;
	}

	/**
	 * Resets the stored value and disposed of the previously stored value.
	 */
	clear(): void {
		this.value = undefined;
	}

	dispose(): void {
		this._isDisposed = true;
		markAsDisposed(this);
		this._value?.dispose();
		this._value = undefined;
	}

	/**
	 * Clears the value, but does not dispose it.
	 * The old value is returned.
	*/
	clearAndLeak(): T | undefined {
		const oldValue = this._value;
		this._value = undefined;
		if (oldValue) {
			setParentOfDisposable(oldValue, null);
		}
		return oldValue;
	}
}

/**
 * Manages the lifecycle of a disposable value that may be changed like {@link MutableDisposable}, but the value must