Batch/defer history service navigation events (microsoft#163845)

* Batch/defer history service navigation events

Part of microsoft#161622

* Pass store through Event.accumulate

* Remove duplicate function

* Action feedback

* 💄

Co-authored-by: Benjamin Pasero <[email protected]>
Co-authored-by: Benjamin Pasero <[email protected]>

Author: Tyriar

src/vs/base/common/event.ts

@@ -70,23 +70,6 @@ export namespace Event {
 		return debounce<unknown, void>(event, () => void 0, 0, undefined, undefined, disposable);
 	}
 
-	/**
-	 * Debounces an event, firing after some delay (default=0) with an array of all event original objects.
-	 *
-	 * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
-	 * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
-	 * returned event causes this utility to leak a listener on the original event.
-	 */
-	export function accumulate<T>(event: Event<T>, delay: number = 0, disposable?: DisposableStore): Event<T[]> {
-		return Event.debounce<T, T[]>(event, (last, e) => {
-			if (!last) {
-				return [e];
-			}
-			last.push(e);
-			return last;
-		}, delay, undefined, undefined, disposable);
-	}
-
 	/**
 	 * Given an event, returns another event which only fires once.
 	 */
@@ -260,6 +243,23 @@ export namespace Event {
 		return emitter.event;
 	}
 
+	/**
+	 * Debounces an event, firing after some delay (default=0) with an array of all event original objects.
+	 *
+	 * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
+	 * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
+	 * returned event causes this utility to leak a listener on the original event.
+	 */
+	export function accumulate<T>(event: Event<T>, delay: number = 0, disposable?: DisposableStore): Event<T[]> {
+		return Event.debounce<T, T[]>(event, (last, e) => {
+			if (!last) {
+				return [e];
+			}
+			last.push(e);
+			return last;
+		}, delay, undefined, undefined, disposable);
+	}
+
 	/**
 	 * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
 	 * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the

src/vs/workbench/services/history/browser/historyService.ts

@@ -160,9 +160,12 @@ export class HistoryService extends Disposable implements IHistoryService {
 		this.handleActiveEditorChange(activeEditorGroup, activeEditorPane);
 
 		// Listen to selection changes if the editor pane
-		// is having a selection concept.
+		// is having a selection concept. We use `accumulate`
+		// on the event to reduce the pressure on the editor
+		// to reduce input latency.
+
 		if (isEditorPaneWithSelection(activeEditorPane)) {
-			this.activeEditorListeners.add(activeEditorPane.onDidChangeSelection(e => this.handleActiveEditorSelectionChangeEvent(activeEditorGroup, activeEditorPane, e)));
+			this.activeEditorListeners.add(Event.accumulate(activeEditorPane.onDidChangeSelection)(e => this.handleActiveEditorSelectionChangeEvents(activeEditorGroup, activeEditorPane, e)));
 		}
 
 		// Context keys
@@ -198,8 +201,10 @@ export class HistoryService extends Disposable implements IHistoryService {
 		this.handleActiveEditorChangeInNavigationStacks(group, editorPane);
 	}
 
-	private handleActiveEditorSelectionChangeEvent(group: IEditorGroup, editorPane: IEditorPaneWithSelection, event: IEditorPaneSelectionChangeEvent): void {
-		this.handleActiveEditorSelectionChangeInNavigationStacks(group, editorPane, event);
+	private handleActiveEditorSelectionChangeEvents(group: IEditorGroup, editorPane: IEditorPaneWithSelection, events: IEditorPaneSelectionChangeEvent[]): void {
+		for (const event of events) {
+			this.handleActiveEditorSelectionChangeInNavigationStacks(group, editorPane, event);
+		}
 	}
 
 	private move(event: FileOperationEvent): void {