Add performance.now (#1633)

BUILD.gn

@@ -104,6 +104,7 @@ ts_sources = [
   "js/util.ts",
   "js/workers.ts",
   "js/write_file.ts",
+  "js/performance.ts",
   "tsconfig.json",
 
   # Listing package.json and yarn.lock as sources ensures the bundle is rebuilt

js/globals.ts

@@ -21,6 +21,7 @@ import * as timers from "./timers";
 import * as url from "./url";
 import * as urlSearchParams from "./url_search_params";
 import * as workers from "./workers";
+import * as performanceUtil from "./performance";
 
 // These imports are not exposed and therefore are fine to just import the
 // symbols required.
@@ -93,4 +94,6 @@ export type TextEncoder = textEncoding.TextEncoder;
 window.TextDecoder = textEncoding.TextDecoder;
 export type TextDecoder = textEncoding.TextDecoder;
 
+window.performance = new performanceUtil.Performance();
+
 window.workerMain = workers.workerMain;

js/performance.ts

@@ -0,0 +1,29 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import * as msg from "gen/msg_generated";
+import { sendSync } from "./dispatch";
+import * as flatbuffers from "./flatbuffers";
+import { assert } from "./util";
+
+export class Performance {
+  timeOrigin = 0;
+
+  constructor() {
+    this.timeOrigin = new Date().getTime();
+  }
+
+  /** Returns a current time from Deno's start
+   *
+   *       const t = performance.now();
+   *       console.log(`${t} ms since start!`);
+   */
+  now(): number {
+    const builder = flatbuffers.createBuilder();
+    msg.Now.startNow(builder);
+    const inner = msg.Now.endNow(builder);
+    const baseRes = sendSync(builder, msg.Any.Now, inner)!;
+    assert(msg.Any.NowRes === baseRes.innerType());
+    const res = new msg.NowRes();
+    assert(baseRes.inner(res) != null);
+    return res.time().toFloat64() - this.timeOrigin;
+  }
+}

js/performance_test.ts

@@ -0,0 +1,10 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { test, assert } from "./test_util.ts";
+
+test(function now() {
+  const start = performance.now();
+  setTimeout(() => {
+    const end = performance.now();
+    assert(end - start >= 10);
+  }, 10);
+});

js/unit_tests.ts

@@ -43,6 +43,7 @@ import "./truncate_test.ts";
 import "./url_test.ts";
 import "./url_search_params_test.ts";
 import "./write_file_test.ts";
+import "./performance_test.ts";
 
 import "../tools/util_test.ts";
 

src/msg.fbs

@@ -59,7 +59,9 @@ union Any {
   Run,
   RunRes,
   RunStatus,
-  RunStatusRes
+  RunStatusRes,
+  Now,
+  NowRes
 }
 
 enum ErrorKind: byte {
@@ -475,4 +477,10 @@ table RunStatusRes {
   exit_signal: int;
 }
 
+table Now {}
+
+table NowRes {
+  time: uint64;
+}
+
 root_type Base;

src/ops.rs

@@ -39,8 +39,7 @@ use std::path::Path;
 use std::path::PathBuf;
 use std::process::Command;
 use std::sync::Arc;
-use std::time::UNIX_EPOCH;
-use std::time::{Duration, Instant};
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 use tokio;
 use tokio::net::TcpListener;
 use tokio::net::TcpStream;
@@ -121,6 +120,7 @@ pub fn dispatch(
       msg::Any::WorkerPostMessage => op_worker_post_message,
       msg::Any::Write => op_write,
       msg::Any::WriteFile => op_write_file,
+      msg::Any::Now => op_now,
       _ => panic!(format!(
         "Unhandled message {}",
         msg::enum_name_any(inner_type)
@@ -173,6 +173,30 @@ pub fn dispatch(
   (base.sync(), boxed_op)
 }
 
+fn op_now(
+  _state: &Arc<IsolateState>,
+  base: &msg::Base<'_>,
+  data: libdeno::deno_buf,
+) -> Box<Op> {
+  assert_eq!(data.len(), 0);
+  let start = SystemTime::now();
+  let since_the_epoch = start.duration_since(UNIX_EPOCH).unwrap();
+  let time = since_the_epoch.as_secs() as u64 * 1000
+    + since_the_epoch.subsec_millis() as u64;
+
+  let builder = &mut FlatBufferBuilder::new();
+  let inner = msg::NowRes::create(builder, &msg::NowResArgs { time: time });
+  ok_future(serialize_response(
+    base.cmd_id(),
+    builder,
+    msg::BaseArgs {
+      inner: Some(inner.as_union_value()),
+      inner_type: msg::Any::NowRes,
+      ..Default::default()
+    },
+  ))
+}
+
 fn op_exit(
   _config: &Arc<IsolateState>,
   base: &msg::Base<'_>,