Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 693 insertions, 0 deletions

diff --git a/browser/modules/ProcessHangMonitor.jsm b/browser/modules/ProcessHangMonitor.jsm
new file mode 100644
index 0000000000..f28a7994bc
--- /dev/null
+++ b/browser/modules/ProcessHangMonitor.jsm
@@ -0,0 +1,693 @@
+/* -*- mode: js; indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* 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/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["ProcessHangMonitor"];
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+/**
+ * Elides the middle of a string by replacing it with an elipsis if it is
+ * longer than `threshold` characters. Does its best to not break up grapheme
+ * clusters.
+ */
+function elideMiddleOfString(str, threshold) {
+  const searchDistance = 5;
+  const stubLength = threshold / 2 - searchDistance;
+  if (str.length <= threshold || stubLength < searchDistance) {
+    return str;
+  }
+
+  function searchElisionPoint(position) {
+    let unsplittableCharacter = c => /[\p{M}\uDC00-\uDFFF]/u.test(c);
+    for (let i = 0; i < searchDistance; i++) {
+      if (!unsplittableCharacter(str[position + i])) {
+        return position + i;
+      }
+
+      if (!unsplittableCharacter(str[position - i])) {
+        return position - i;
+      }
+    }
+    return position;
+  }
+
+  let elisionStart = searchElisionPoint(stubLength);
+  let elisionEnd = searchElisionPoint(str.length - stubLength);
+  if (elisionStart < elisionEnd) {
+    str = str.slice(0, elisionStart) + "\u2026" + str.slice(elisionEnd);
+  }
+  return str;
+}
+
+/**
+ * This JSM is responsible for observing content process hang reports
+ * and asking the user what to do about them. See nsIHangReport for
+ * the platform interface.
+ */
+
+var ProcessHangMonitor = {
+  /**
+   * This timeout is the wait period applied after a user selects "Wait" in
+   * an existing notification.
+   */
+  get WAIT_EXPIRATION_TIME() {
+    try {
+      return Services.prefs.getIntPref("browser.hangNotification.waitPeriod");
+    } catch (ex) {
+      return 10000;
+    }
+  },
+
+  /**
+   * Should only be set to true once the quit-application-granted notification
+   * has been fired.
+   */
+  _shuttingDown: false,
+
+  /**
+   * Collection of hang reports that haven't expired or been dismissed
+   * by the user. These are nsIHangReports. They are mapped to objects
+   * containing:
+   * - notificationTime: when (Cu.now()) we first showed a notification
+   * - waitCount: how often the user asked to wait for the script to finish
+   * - lastReportFromChild: when (Cu.now()) we last got hang info from the
+   *   child.
+   */
+  _activeReports: new Map(),
+
+  /**
+   * Collection of hang reports that have been suppressed for a short
+   * period of time. Value is an object like in _activeReports, but also
+   * including a `timer` prop, which is an nsITimer for when the wait time
+   * expires.
+   */
+  _pausedReports: new Map(),
+
+  /**
+   * Initialize hang reporting. Called once in the parent process.
+   */
+  init() {
+    Services.obs.addObserver(this, "process-hang-report");
+    Services.obs.addObserver(this, "clear-hang-report");
+    Services.obs.addObserver(this, "quit-application-granted");
+    Services.obs.addObserver(this, "xpcom-shutdown");
+    Services.ww.registerNotification(this);
+    Services.telemetry.setEventRecordingEnabled("slow_script_warning", true);
+  },
+
+  /**
+   * Terminate JavaScript associated with the hang being reported for
+   * the selected browser in |win|.
+   */
+  terminateScript(win) {
+    this.handleUserInput(win, report => report.terminateScript());
+  },
+
+  /**
+   * Start devtools debugger for JavaScript associated with the hang
+   * being reported for the selected browser in |win|.
+   */
+  debugScript(win) {
+    this.handleUserInput(win, report => {
+      function callback() {
+        report.endStartingDebugger();
+      }
+
+      this._recordTelemetryForReport(report, "debugging");
+      report.beginStartingDebugger();
+
+      let svc = Cc["@mozilla.org/dom/slow-script-debug;1"].getService(
+        Ci.nsISlowScriptDebug
+      );
+      let handler = svc.remoteActivationHandler;
+      handler.handleSlowScriptDebug(report.scriptBrowser, callback);
+    });
+  },
+
+  /**
+   * Dismiss the browser notification and invoke an appropriate action based on
+   * the hang type.
+   */
+  stopIt(win) {
+    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
+    if (!report) {
+      return;
+    }
+
+    this._recordTelemetryForReport(report, "user-aborted");
+    this.terminateScript(win);
+  },
+
+  /**
+   * Terminate the script causing this report. This is done without
+   * updating any report notifications.
+   */
+  stopHang(report, endReason, backupInfo) {
+    this._recordTelemetryForReport(report, endReason, backupInfo);
+    report.terminateScript();
+  },
+
+  /**
+   * Dismiss the notification, clear the report from the active list and set up
+   * a new timer to track a wait period during which we won't notify.
+   */
+  waitLonger(win) {
+    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
+    if (!report) {
+      return;
+    }
+    // Update the other info we keep.
+    let reportInfo = this._activeReports.get(report);
+    reportInfo.waitCount++;
+
+    // Remove the report from the active list.
+    this.removeActiveReport(report);
+
+    // NOTE, we didn't call userCanceled on nsIHangReport here. This insures
+    // we don't repeatedly generate and cache crash report data for this hang
+    // in the process hang reporter. It already has one report for the browser
+    // process we want it hold onto.
+
+    // Create a new wait timer with notify callback
+    let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+    timer.initWithCallback(
+      () => {
+        for (let [stashedReport, pausedInfo] of this._pausedReports) {
+          if (pausedInfo.timer === timer) {
+            this.removePausedReport(stashedReport);
+
+            // We're still hung, so move the report back to the active
+            // list and update the UI.
+            this._activeReports.set(report, pausedInfo);
+            this.updateWindows();
+            break;
+          }
+        }
+      },
+      this.WAIT_EXPIRATION_TIME,
+      timer.TYPE_ONE_SHOT
+    );
+
+    reportInfo.timer = timer;
+    this._pausedReports.set(report, reportInfo);
+
+    // remove the browser notification associated with this hang
+    this.updateWindows();
+  },
+
+  /**
+   * If there is a hang report associated with the selected browser in
+   * |win|, invoke |func| on that report and stop notifying the user
+   * about it.
+   */
+  handleUserInput(win, func) {
+    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
+    if (!report) {
+      return null;
+    }
+    this.removeActiveReport(report);
+
+    return func(report);
+  },
+
+  observe(subject, topic, data) {
+    switch (topic) {
+      case "xpcom-shutdown": {
+        Services.obs.removeObserver(this, "xpcom-shutdown");
+        Services.obs.removeObserver(this, "process-hang-report");
+        Services.obs.removeObserver(this, "clear-hang-report");
+        Services.obs.removeObserver(this, "quit-application-granted");
+        Services.ww.unregisterNotification(this);
+        break;
+      }
+
+      case "quit-application-granted": {
+        this.onQuitApplicationGranted();
+        break;
+      }
+
+      case "process-hang-report": {
+        this.reportHang(subject.QueryInterface(Ci.nsIHangReport));
+        break;
+      }
+
+      case "clear-hang-report": {
+        this.clearHang(subject.QueryInterface(Ci.nsIHangReport));
+        break;
+      }
+
+      case "domwindowopened": {
+        // Install event listeners on the new window in case one of
+        // its tabs is already hung.
+        let win = subject;
+        let listener = ev => {
+          win.removeEventListener("load", listener, true);
+          this.updateWindows();
+        };
+        win.addEventListener("load", listener, true);
+        break;
+      }
+
+      case "domwindowclosed": {
+        let win = subject;
+        this.onWindowClosed(win);
+        break;
+      }
+    }
+  },
+
+  /**
+   * Called early on in the shutdown sequence. We take this opportunity to
+   * take any pre-existing hang reports, and terminate them. We also put
+   * ourselves in a state so that if any more hang reports show up while
+   * we're shutting down, we terminate them immediately.
+   */
+  onQuitApplicationGranted() {
+    this._shuttingDown = true;
+    this.stopAllHangs("quit-application-granted");
+    this.updateWindows();
+  },
+
+  onWindowClosed(win) {
+    let maybeStopHang = report => {
+      let hungBrowserWindow = null;
+      try {
+        hungBrowserWindow = report.scriptBrowser.ownerGlobal;
+      } catch (e) {
+        // Ignore failures to get the script browser - we'll be
+        // conservative, and assume that if we cannot access the
+        // window that belongs to this report that we should stop
+        // the hang.
+      }
+      if (!hungBrowserWindow || hungBrowserWindow == win) {
+        this.stopHang(report, "window-closed");
+        return true;
+      }
+      return false;
+    };
+
+    // If there are any script hangs for browsers that are in this window
+    // that is closing, we can stop them now.
+    for (let [report] of this._activeReports) {
+      if (maybeStopHang(report)) {
+        this._activeReports.delete(report);
+      }
+    }
+
+    for (let [pausedReport] of this._pausedReports) {
+      if (maybeStopHang(pausedReport)) {
+        this.removePausedReport(pausedReport);
+      }
+    }
+
+    this.updateWindows();
+  },
+
+  stopAllHangs(endReason) {
+    for (let [report] of this._activeReports) {
+      this.stopHang(report, endReason);
+    }
+
+    this._activeReports = new Map();
+
+    for (let [pausedReport] of this._pausedReports) {
+      this.stopHang(pausedReport, endReason);
+      this.removePausedReport(pausedReport);
+    }
+  },
+
+  /**
+   * Find a active hang report for the given <browser> element.
+   */
+  findActiveReport(browser) {
+    let frameLoader = browser.frameLoader;
+    for (let report of this._activeReports.keys()) {
+      if (report.isReportForBrowserOrChildren(frameLoader)) {
+        return report;
+      }
+    }
+    return null;
+  },
+
+  /**
+   * Find a paused hang report for the given <browser> element.
+   */
+  findPausedReport(browser) {
+    let frameLoader = browser.frameLoader;
+    for (let [report] of this._pausedReports) {
+      if (report.isReportForBrowserOrChildren(frameLoader)) {
+        return report;
+      }
+    }
+    return null;
+  },
+
+  /**
+   * Tell telemetry about the report.
+   */
+  _recordTelemetryForReport(report, endReason, backupInfo) {
+    let info =
+      this._activeReports.get(report) ||
+      this._pausedReports.get(report) ||
+      backupInfo;
+    if (!info) {
+      return;
+    }
+    try {
+      let uri_type;
+      if (report.addonId) {
+        uri_type = "extension";
+      } else if (report.scriptFileName?.startsWith("debugger")) {
+        uri_type = "devtools";
+      } else {
+        try {
+          let url = new URL(report.scriptFileName);
+          if (url.protocol == "chrome:" || url.protocol == "resource:") {
+            uri_type = "browser";
+          } else {
+            uri_type = "content";
+          }
+        } catch (ex) {
+          console.error(ex);
+          uri_type = "unknown";
+        }
+      }
+      let uptime = 0;
+      if (info.notificationTime) {
+        uptime = Cu.now() - info.notificationTime;
+      }
+      uptime = "" + uptime;
+      // We combine the duration of the hang in the content process with the
+      // time since we were last told about the hang in the parent. This is
+      // not the same as the time we showed a notification, as we only do that
+      // for the currently selected browser. It's as messy as it is because
+      // there is no cross-process monotonically increasing timestamp we can
+      // use. :-(
+      let hangDuration =
+        report.hangDuration + Cu.now() - info.lastReportFromChild;
+      Services.telemetry.recordEvent(
+        "slow_script_warning",
+        "shown",
+        "content",
+        null,
+        {
+          end_reason: endReason,
+          hang_duration: "" + hangDuration,
+          n_tab_deselect: "" + info.deselectCount,
+          uri_type,
+          uptime,
+          wait_count: "" + info.waitCount,
+        }
+      );
+    } catch (ex) {
+      console.error(ex);
+    }
+  },
+
+  /**
+   * Remove an active hang report from the active list and cancel the timer
+   * associated with it.
+   */
+  removeActiveReport(report) {
+    this._activeReports.delete(report);
+    this.updateWindows();
+  },
+
+  /**
+   * Remove a paused hang report from the paused list and cancel the timer
+   * associated with it.
+   */
+  removePausedReport(report) {
+    let info = this._pausedReports.get(report);
+    info?.timer?.cancel();
+    this._pausedReports.delete(report);
+  },
+
+  /**
+   * Iterate over all XUL windows and ensure that the proper hang
+   * reports are shown for each one. Also install event handlers in
+   * each window to watch for events that would cause a different hang
+   * report to be displayed.
+   */
+  updateWindows() {
+    let e = Services.wm.getEnumerator("navigator:browser");
+
+    // If it turns out we have no windows (this can happen on macOS),
+    // we have no opportunity to ask the user whether or not they want
+    // to stop the hang or wait, so we'll opt for stopping the hang.
+    if (!e.hasMoreElements()) {
+      this.stopAllHangs("no-windows-left");
+      return;
+    }
+
+    for (let win of e) {
+      this.updateWindow(win);
+
+      // Only listen for these events if there are active hang reports.
+      if (this._activeReports.size) {
+        this.trackWindow(win);
+      } else {
+        this.untrackWindow(win);
+      }
+    }
+  },
+
+  /**
+   * If there is a hang report for the current tab in |win|, display it.
+   */
+  updateWindow(win) {
+    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
+
+    if (report) {
+      let info = this._activeReports.get(report);
+      if (info && !info.notificationTime) {
+        info.notificationTime = Cu.now();
+      }
+      this.showNotification(win, report);
+    } else {
+      this.hideNotification(win);
+    }
+  },
+
+  /**
+   * Show the notification for a hang.
+   */
+  showNotification(win, report) {
+    let bundle = win.gNavigatorBundle;
+
+    let buttons = [
+      {
+        label: bundle.getString("processHang.button_stop2.label"),
+        accessKey: bundle.getString("processHang.button_stop2.accessKey"),
+        callback() {
+          ProcessHangMonitor.stopIt(win);
+        },
+      },
+    ];
+
+    let message;
+    let doc = win.document;
+    let brandShortName = doc
+      .getElementById("bundle_brand")
+      .getString("brandShortName");
+    let notificationTag;
+    if (report.addonId) {
+      notificationTag = report.addonId;
+      let aps = Cc["@mozilla.org/addons/policy-service;1"].getService(
+        Ci.nsIAddonPolicyService
+      );
+
+      let addonName = aps.getExtensionName(report.addonId);
+
+      message = bundle.getFormattedString("processHang.add-on.label2", [
+        addonName,
+        brandShortName,
+      ]);
+
+      buttons.unshift({
+        label: bundle.getString("processHang.add-on.learn-more.text"),
+        link: "https://support.mozilla.org/kb/warning-unresponsive-script#w_other-causes",
+      });
+    } else {
+      let scriptBrowser = report.scriptBrowser;
+      if (scriptBrowser == win.gBrowser?.selectedBrowser) {
+        notificationTag = "selected-tab";
+        message = bundle.getFormattedString("processHang.selected_tab.label", [
+          brandShortName,
+        ]);
+      } else {
+        let tab =
+          scriptBrowser?.ownerGlobal.gBrowser?.getTabForBrowser(scriptBrowser);
+        if (!tab) {
+          notificationTag = "nonspecific_tab";
+          message = bundle.getFormattedString(
+            "processHang.nonspecific_tab.label",
+            [brandShortName]
+          );
+        } else {
+          notificationTag = scriptBrowser.browserId.toString();
+          let title = tab.getAttribute("label");
+          title = elideMiddleOfString(title, 60);
+          message = bundle.getFormattedString(
+            "processHang.specific_tab.label",
+            [title, brandShortName]
+          );
+        }
+      }
+    }
+
+    let notification =
+      win.gNotificationBox.getNotificationWithValue("process-hang");
+    if (notificationTag == notification?.getAttribute("notification-tag")) {
+      return;
+    }
+
+    if (notification) {
+      notification.label = message;
+      notification.setAttribute("notification-tag", notificationTag);
+      return;
+    }
+
+    // Show the "debug script" button unconditionally if we are in Developer edition,
+    // or, if DevTools are opened on the slow tab.
+    if (
+      AppConstants.MOZ_DEV_EDITION ||
+      report.scriptBrowser.browsingContext.watchedByDevTools
+    ) {
+      buttons.push({
+        label: bundle.getString("processHang.button_debug.label"),
+        accessKey: bundle.getString("processHang.button_debug.accessKey"),
+        callback() {
+          ProcessHangMonitor.debugScript(win);
+        },
+      });
+    }
+
+    win.gNotificationBox
+      .appendNotification(
+        "process-hang",
+        {
+          label: message,
+          image: "chrome://browser/content/aboutRobots-icon.png",
+          priority: win.gNotificationBox.PRIORITY_INFO_HIGH,
+          eventCallback: event => {
+            if (event == "dismissed") {
+              ProcessHangMonitor.waitLonger(win);
+            }
+          },
+        },
+        buttons
+      )
+      .setAttribute("notification-tag", notificationTag);
+  },
+
+  /**
+   * Ensure that no hang notifications are visible in |win|.
+   */
+  hideNotification(win) {
+    let notification =
+      win.gNotificationBox.getNotificationWithValue("process-hang");
+    if (notification) {
+      win.gNotificationBox.removeNotification(notification);
+    }
+  },
+
+  /**
+   * Install event handlers on |win| to watch for events that would
+   * cause a different hang report to be displayed.
+   */
+  trackWindow(win) {
+    win.gBrowser.tabContainer.addEventListener("TabSelect", this, true);
+    win.gBrowser.tabContainer.addEventListener(
+      "TabRemotenessChange",
+      this,
+      true
+    );
+  },
+
+  untrackWindow(win) {
+    win.gBrowser.tabContainer.removeEventListener("TabSelect", this, true);
+    win.gBrowser.tabContainer.removeEventListener(
+      "TabRemotenessChange",
+      this,
+      true
+    );
+  },
+
+  handleEvent(event) {
+    let win = event.target.ownerGlobal;
+
+    // If a new tab is selected or if a tab changes remoteness, then
+    // we may need to show or hide a hang notification.
+    if (event.type == "TabSelect" || event.type == "TabRemotenessChange") {
+      if (event.type == "TabSelect" && event.detail.previousTab) {
+        // If we've got a notification, check the previous tab's report and
+        // indicate the user switched tabs while the notification was up.
+        let r =
+          this.findActiveReport(event.detail.previousTab.linkedBrowser) ||
+          this.findPausedReport(event.detail.previousTab.linkedBrowser);
+        if (r) {
+          let info = this._activeReports.get(r) || this._pausedReports.get(r);
+          info.deselectCount++;
+        }
+      }
+      this.updateWindow(win);
+    }
+  },
+
+  /**
+   * Handle a potentially new hang report. If it hasn't been seen
+   * before, show a notification for it in all open XUL windows.
+   */
+  reportHang(report) {
+    let now = Cu.now();
+    if (this._shuttingDown) {
+      this.stopHang(report, "shutdown-in-progress", {
+        lastReportFromChild: now,
+        waitCount: 0,
+        deselectCount: 0,
+      });
+      return;
+    }
+
+    // If this hang was already reported reset the timer for it.
+    if (this._activeReports.has(report)) {
+      this._activeReports.get(report).lastReportFromChild = now;
+      // if this report is in active but doesn't have a notification associated
+      // with it, display a notification.
+      this.updateWindows();
+      return;
+    }
+
+    // If this hang was already reported and paused by the user ignore it.
+    if (this._pausedReports.has(report)) {
+      this._pausedReports.get(report).lastReportFromChild = now;
+      return;
+    }
+
+    // On e10s this counts slow-script notice only once.
+    // This code is not reached on non-e10s.
+    Services.telemetry.getHistogramById("SLOW_SCRIPT_NOTICE_COUNT").add();
+
+    this._activeReports.set(report, {
+      deselectCount: 0,
+      lastReportFromChild: now,
+      waitCount: 0,
+    });
+    this.updateWindows();
+  },
+
+  clearHang(report) {
+    this._recordTelemetryForReport(report, "cleared");
+
+    this.removeActiveReport(report);
+    this.removePausedReport(report);
+    report.userCanceled();
+  },
+};