path: root/testing/talos/talos/pageloader/chrome/tscroll.js

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* eslint-env mozilla/frame-script */

// Note: This file is used at both tscrollx and tp5o_scroll. With the former as
//       unprivileged code.
// - Please make sure that any changes apply cleanly to all use cases.

function testScroll(target, stepSize, opt_reportFunc, opt_numSteps) {
  var win;
  if (target == "content") {
    target = content.wrappedJSObject;
    win = content;
  } else {
    win = window;
  }

  var result = {
    names: [],
    values: [],
  };
  // We report multiple results, so we base the name on the path.
  // Everything after '/tp5n/' if exists (for tp5o_scroll), or the file name at
  // the path if non-empty (e.g. with tscrollx), or the last dir otherwise (e.g.
  // 'mydir' for 'http://my.domain/dir1/mydir/').
  var href = win.location.href;
  var testBaseName =
    href.split("/tp5n/")[1] ||
    href.split("/").pop() ||
    href.split("/").splice(-2, 1)[0] ||
    "REALLY_WEIRD_URI";

  // Verbatim copy from talos-powers/content/TalosPowersContent.js
  // If the origin changes, this copy should be updated.
  TalosPowersParent = {
    replyId: 1,

    // dispatch an event to the framescript and register the result/callback event
    exec(commandName, arg, callback, opt_custom_window) {
      let win = opt_custom_window || window;
      let replyEvent = "TalosPowers:ParentExec:ReplyEvent:" + this.replyId++;
      if (callback) {
        win.addEventListener(
          replyEvent,
          function (e) {
            callback(e.detail);
          },
          { once: true }
        );
      }
      win.dispatchEvent(
        new win.CustomEvent("TalosPowers:ParentExec:QueryEvent", {
          bubbles: true,
          detail: {
            command: {
              name: commandName,
              data: arg,
            },
            listeningTo: replyEvent,
          },
        })
      );
    },
  };
  // End of code from talos-powers

  var report;
  /**
   * Sets up the value of 'report' as a function for reporting the test result[s].
   * Chooses between the "usual" tpRecordTime which the pageloader addon injects
   * to pages, or a custom function in case we're a framescript which pageloader
   * added to the tested page, or a debug tpRecordTime from talos-debug.js if
   * running in a plain browser.
   *
   * @returns Promise
   */
  function P_setupReportFn() {
    return new Promise(function (resolve) {
      report = opt_reportFunc || win.tpRecordTime;
      if (report == "PageLoader:RecordTime") {
        report = function (duration, start, name) {
          var msg = { time: duration, startTime: start, testName: name };
          sendAsyncMessage("PageLoader:RecordTime", msg);
        };
        resolve();
        return;
      }

      // Not part of the test and does nothing if we're within talos.
      // Provides an alternative tpRecordTime (with some stats display) if running in a browser.
      if (!report && document.head) {
        var imported = document.createElement("script");
        imported.addEventListener("load", function () {
          report = tpRecordTime;
          resolve();
        });

        imported.src =
          "../../scripts/talos-debug.js?dummy=" + win.performance.now(); // For some browsers to re-read
        document.head.appendChild(imported);
        return;
      }

      resolve();
    });
  }

  function FP_wait(ms) {
    return function () {
      return new Promise(function (resolve) {
        win.setTimeout(resolve, ms);
      });
    };
  }

  function rAF(fn) {
    return win.requestAnimationFrame(fn);
  }

  function P_rAF() {
    return new Promise(function (resolve) {
      rAF(resolve);
    });
  }

  function P_MozAfterPaint() {
    return new Promise(function (resolve) {
      win.addEventListener("MozAfterPaint", () => resolve(), { once: true });
    });
  }

  var isWindow = target.self === target;

  var getPos = isWindow
    ? function () {
        return target.pageYOffset;
      }
    : function () {
        return target.scrollTop;
      };

  var gotoTop = isWindow
    ? function () {
        target.scroll(0, 0);
        ensureScroll();
      }
    : function () {
        target.scrollTop = 0;
        ensureScroll();
      };

  var doScrollTick = isWindow
    ? function () {
        target.scrollBy(0, stepSize);
        ensureScroll();
      }
    : function () {
        target.scrollTop += stepSize;
        ensureScroll();
      };

  var setSmooth = isWindow
    ? function () {
        target.document.scrollingElement.style.scrollBehavior = "smooth";
      }
    : function () {
        target.style.scrollBehavior = "smooth";
      };

  var gotoBottom = isWindow
    ? function () {
        target.scrollTo(0, target.scrollMaxY);
      }
    : function () {
        target.scrollTop = target.scrollHeight;
      };

  function ensureScroll() {
    // Ensure scroll by reading computed values. screenY is for X11.
    if (!this.dummyEnsureScroll) {
      this.dummyEnsureScroll = 1;
    }
    this.dummyEnsureScroll += win.screenY + getPos();
  }

  // For reference, rAF should fire on vsync, but Gecko currently doesn't use vsync.
  // Instead, it uses 1000/layout.frame_rate
  // (with 60 as default value when layout.frame_rate == -1).
  function P_syncScrollTest() {
    return new Promise(function (resolve) {
      // We should be at the top of the page now.
      var start = win.performance.now();
      var lastScrollPos = getPos();
      var lastScrollTime = start;
      var durations = [];

      function tick() {
        var now = win.performance.now();
        var duration = now - lastScrollTime;
        lastScrollTime = now;

        durations.push(duration);
        doScrollTick();

        /* stop scrolling if we can't scroll more, or if we've reached requested number of steps */
        if (
          getPos() == lastScrollPos ||
          (opt_numSteps && durations.length >= opt_numSteps + 2)
        ) {
          let profilerPaused = Promise.resolve();
          if (typeof TalosContentProfiler !== "undefined") {
            profilerPaused = TalosContentProfiler.pause(testBaseName, true);
          }

          profilerPaused.then(() => {
            // Note: The first (1-5) intervals WILL be longer than the rest.
            // First interval might include initial rendering and be extra slow.
            // Also requestAnimationFrame needs to sync (optimally in 1 frame) after long frames.
            // Suggested: Ignore the first 5 intervals.

            durations.pop(); // Last step was 0.
            durations.pop(); // and the prev one was shorter and with end-of-page logic, ignore both.

            if (win.talosDebug) {
              win.talosDebug.displayData = true;
            } // In a browser: also display all data points.

            // For analysis (otherwise, it's too many data points for talos):
            var sum = 0;
            for (var i = 0; i < durations.length; i++) {
              sum += Number(durations[i]);
            }

            // Report average interval or (failsafe) 0 if no intervls were recorded
            result.values.push(durations.length ? sum / durations.length : 0);
            result.names.push(testBaseName);
            resolve();
          });
          return;
        }

        lastScrollPos = getPos();
        P_MozAfterPaint().then(tick);
      }

      if (typeof TalosContentProfiler !== "undefined") {
        TalosContentProfiler.resume(testBaseName, true).then(() => {
          rAF(tick);
        });
      }
    });
  }

  function P_testAPZScroll() {
    var APZ_MEASURE_MS = 1000;

    function startFrameTimeRecording(cb) {
      TalosPowersParent.exec("startFrameTimeRecording", null, cb, win);
    }

    function stopFrameTimeRecording(handle, cb) {
      TalosPowersParent.exec("stopFrameTimeRecording", handle, cb, win);
    }

    return new Promise(function (resolve, reject) {
      setSmooth();

      var handle = -1;
      startFrameTimeRecording(function (rv) {
        handle = rv;
      });

      // Get the measurements after APZ_MEASURE_MS of scrolling
      win.setTimeout(function () {
        stopFrameTimeRecording(handle, function (intervals) {
          function average(arr) {
            var sum = 0;
            for (var i = 0; i < arr.length; i++) {
              sum += arr[i];
            }
            return arr.length ? sum / arr.length : 0;
          }

          // remove two frames on each side of the recording to get a cleaner result
          result.values.push(average(intervals.slice(2, intervals.length - 2)));
          result.names.push("CSSOM." + testBaseName);

          resolve();
        });
      }, APZ_MEASURE_MS);

      gotoBottom(); // trigger the APZ scroll
    });
  }

  P_setupReportFn()
    .then(FP_wait(260))
    .then(gotoTop)
    .then(P_rAF)
    .then(P_syncScrollTest)
    .then(gotoTop)
    .then(FP_wait(260))
    .then(P_testAPZScroll)
    .then(function () {
      report(result.values.join(","), 0, result.names.join(","));
    });
}

// This code below here is unique to tscroll.js inside of pageloader
try {
  function handleMessageFromChrome(message) {
    var payload = message.data.details;
    testScroll(
      payload.target,
      payload.stepSize,
      "PageLoader:RecordTime",
      payload.opt_numSteps
    );
  }

  addMessageListener("PageLoader:ScrollTest", handleMessageFromChrome);
} catch (e) {}