Merge from vscode c873727e8bac95e7cbf5b154a9e6ae0986f2ce18 (#6446)

src/vs/base/common/lifecycle.ts

@@ -207,6 +207,43 @@ export class MutableDisposable<T extends IDisposable> implements IDisposable {
 	}
 }
 
+/**
+ * Wrapper class that stores a disposable that is not currently "owned" by anyone.
+ *
+ * Example use cases:
+ *
+ * - Express that a function/method will take ownership of a disposable parameter.
+ * - Express that a function returns a disposable that the caller must explicitly take ownership of.
+ */
+export class UnownedDisposable<T extends IDisposable> extends Disposable {
+	private _hasBeenAcquired = false;
+	private _value?: T;
+
+	public constructor(value: T) {
+		super();
+		this._value = value;
+	}
+
+	public acquire(): T {
+		if (this._hasBeenAcquired) {
+			throw new Error('This disposable has already been acquired');
+		}
+		this._hasBeenAcquired = true;
+		const value = this._value!;
+		this._value = undefined;
+		return value;
+	}
+
+	public dispose() {
+		super.dispose();
+		if (!this._hasBeenAcquired) {
+			this._hasBeenAcquired = true;
+			this._value!.dispose();
+			this._value = undefined;
+		}
+	}
+}
+
 export interface IReference<T> extends IDisposable {
 	readonly object: T;
 }