1 files changed, 75 insertions, 0 deletions
diff --git a/src/compiler/Stats.ts b/src/compiler/Stats.ts
new file mode 100644
index 000000000..81c7f92ef
--- /dev/null
+++ b/src/compiler/Stats.ts
@@ -0,0 +1,75 @@
+// @ts-nocheck
+
+const now = (typeof process !== 'undefined' && process.hrtime)
+	? () => {
+		const t = process.hrtime();
+		return t[0] * 1e3 + t[1] / 1e6;
+	}
+	: () => self.performance.now();
+
+interface Timing {
+	label: string;
+	start: number;
+	end: number;
+	children: Timing[];
+}
+
+function collapse_timings(timings) {
+	const result = {};
+	timings.forEach(timing => {
+		result[timing.label] = Object.assign({
+			total: timing.end - timing.start
+		}, timing.children && collapse_timings(timing.children));
+	});
+	return result;
+}
+
+export default class Stats {
+	start_time: number;
+	current_timing: Timing;
+	current_children: Timing[];
+	timings: Timing[];
+	stack: Timing[];
+
+	constructor() {
+		this.start_time = now();
+		this.stack = [];
+		this.current_children = this.timings = [];
+	}
+
+	start(label) {
+		const timing = {
+			label,
+			start: now(),
+			end: null,
+			children: []
+		};
+
+		this.current_children.push(timing);
+		this.stack.push(timing);
+
+		this.current_timing = timing;
+		this.current_children = timing.children;
+	}
+
+	stop(label) {
+		if (label !== this.current_timing.label) {
+			throw new Error(`Mismatched timing labels (expected ${this.current_timing.label}, got ${label})`);
+		}
+
+		this.current_timing.end = now();
+		this.stack.pop();
+		this.current_timing = this.stack[this.stack.length - 1];
+		this.current_children = this.current_timing ? this.current_timing.children : this.timings;
+	}
+
+	render() {
+		const timings = Object.assign({
+			total: now() - this.start_time
+		}, collapse_timings(this.timings));
+
+		return {
+			timings
+		};
+	}
+}