Class SingleDocumentPositionTracker

src/shared/vscode/trackers.ts:6–53

import { disposeAll } from "../utils";

export class SingleDocumentPositionTracker implements IAmDisposable {
	// TODO(dantup): Deprecate and remove this in favour of DocumentPositionTracker
	private readonly disposables: IAmDisposable[] = [];
	private readonly tracker: SingleDocumentOffsetTracker = new SingleDocumentOffsetTracker();
	private readonly positionMap: Map<vs.Position, number> = new Map<vs.Position, number>();

	private onPositionsChangedEmitter = new vs.EventEmitter<[vs.TextDocument, Map<vs.Position, vs.Position>]>();
	public readonly onPositionsChanged = this.onPositionsChangedEmitter.event;

	constructor() {
		this.disposables.push(this.tracker);

		this.tracker.onOffsetsChanged(([doc, offsets]) => {
			// Map all our original positions onto new positions based on their
			// new offsets.
			const newPositions = new Map<vs.Position, vs.Position>();
			for (const position of this.positionMap.keys()) {
				const currentOffset = this.positionMap.get(position)!;
				const newOffset = offsets.get(currentOffset);
				if (newOffset)
					newPositions.set(position, doc.positionAt(newOffset));
				else
					newPositions.delete(position);
			}

			this.onPositionsChangedEmitter.fire([doc, newPositions]);
		});
	}

	public clear(): void {
		this.positionMap.clear();
		this.tracker.clear();
	}

	public trackDoc(document: vs.TextDocument, positions: vs.Position[]) {
		// Stash all positions as offsets.
		this.positionMap.clear();
		for (const position of positions)
			this.positionMap.set(position, document.offsetAt(position));

		// Track via the offset tracker.
		this.tracker.trackDoc(document, [...this.positionMap.values()]);
	}

	public dispose() {
		disposeAll(this.disposables);
	}
}

export class SingleDocumentOffsetTracker implements IAmDisposable {
	// TODO(dantup): Deprecate and remove this in favour of DocumentPositionTracker