summaryrefslogtreecommitdiff
path: root/modules/ProcessHangMonitor.jsm
blob: 526fcd23d68b67f1f6b66c184d7b78488fc76874 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
/* -*- 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 Cc = Components.classes;
var Ci = Components.interfaces;
var Cu = Components.utils;

this.EXPORTED_SYMBOLS = ["ProcessHangMonitor"];

Cu.import("resource://gre/modules/AppConstants.jsm");
Cu.import("resource://gre/modules/Services.jsm");

/**
 * 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;
    }
  },

  /**
   * Collection of hang reports that haven't expired or been dismissed
   * by the user. These are nsIHangReports.
   */
  _activeReports: new Set(),

  /**
   * Collection of hang reports that have been suppressed for a short
   * period of time. Value is an nsITimer for when the wait time
   * expires.
   */
  _pausedReports: new Map(),

  /**
   * Initialize hang reporting. Called once in the parent process.
   */
  init: function() {
    Services.obs.addObserver(this, "process-hang-report", false);
    Services.obs.addObserver(this, "clear-hang-report", false);
    Services.obs.addObserver(this, "xpcom-shutdown", false);
    Services.ww.registerNotification(this);
  },

  /**
   * Terminate JavaScript associated with the hang being reported for
   * the selected browser in |win|.
   */
  terminateScript: function(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: function(win) {
    this.handleUserInput(win, report => {
      function callback() {
        report.endStartingDebugger();
      }

      report.beginStartingDebugger();

      let svc = Cc["@mozilla.org/dom/slow-script-debug;1"].getService(Ci.nsISlowScriptDebug);
      let handler = svc.remoteActivationHandler;
      handler.handleSlowScriptDebug(report.scriptBrowser, callback);
    });
  },

  /**
   * Terminate the plugin process associated with a hang being reported
   * for the selected browser in |win|. Will attempt to generate a combined
   * crash report for all processes.
   */
  terminatePlugin: function(win) {
    this.handleUserInput(win, report => report.terminatePlugin());
  },

  /**
   * Dismiss the browser notification and invoke an appropriate action based on
   * the hang type.
   */
  stopIt: function (win) {
    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
    if (!report) {
      return;
    }

    switch (report.hangType) {
      case report.SLOW_SCRIPT:
        this.terminateScript(win);
        break;
      case report.PLUGIN_HANG:
        this.terminatePlugin(win);
        break;
    }
  },

  /**
   * 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: function(win) {
    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
    if (!report) {
      return;
    }
    // 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, otherTimer] of this._pausedReports) {
        if (otherTimer === timer) {
          this.removePausedReport(stashedReport);

          // We're still hung, so move the report back to the active
          // list and update the UI.
          this._activeReports.add(report);
          this.updateWindows();
          break;
        }
      }
    }, this.WAIT_EXPIRATION_TIME, timer.TYPE_ONE_SHOT);

    this._pausedReports.set(report, timer);

    // 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: function(win, func) {
    let report = this.findActiveReport(win.gBrowser.selectedBrowser);
    if (!report) {
      return null;
    }
    this.removeActiveReport(report);

    return func(report);
  },

  observe: function(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.ww.unregisterNotification(this);
        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.QueryInterface(Ci.nsIDOMWindow);
        let listener = (ev) => {
          win.removeEventListener("load", listener, true);
          this.updateWindows();
        };
        win.addEventListener("load", listener, true);
        break;
    }
  },

  /**
   * Find a active hang report for the given <browser> element.
   */
  findActiveReport: function(browser) {
    let frameLoader = browser.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader;
    for (let report of this._activeReports) {
      if (report.isReportForBrowser(frameLoader)) {
        return report;
      }
    }
    return null;
  },

  /**
   * Find a paused hang report for the given <browser> element.
   */
  findPausedReport: function(browser) {
    let frameLoader = browser.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader;
    for (let [report, ] of this._pausedReports) {
      if (report.isReportForBrowser(frameLoader)) {
        return report;
      }
    }
    return null;
  },

  /**
   * Remove an active hang report from the active list and cancel the timer
   * associated with it.
   */
  removeActiveReport: function(report) {
    this._activeReports.delete(report);
    this.updateWindows();
  },

  /**
   * Remove a paused hang report from the paused list and cancel the timer
   * associated with it.
   */
  removePausedReport: function(report) {
    let timer = this._pausedReports.get(report);
    if (timer) {
      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: function() {
    let e = Services.wm.getEnumerator("navigator:browser");
    while (e.hasMoreElements()) {
      let win = e.getNext();

      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: function(win) {
    let report = this.findActiveReport(win.gBrowser.selectedBrowser);

    if (report) {
      this.showNotification(win, report);
    } else {
      this.hideNotification(win);
    }
  },

  /**
   * Show the notification for a hang.
   */
  showNotification: function(win, report) {
    let nb = win.document.getElementById("high-priority-global-notificationbox");
    let notification = nb.getNotificationWithValue("process-hang");
    if (notification) {
      return;
    }

    let bundle = win.gNavigatorBundle;

    let buttons = [{
        label: bundle.getString("processHang.button_stop.label"),
        accessKey: bundle.getString("processHang.button_stop.accessKey"),
        callback: function() {
          ProcessHangMonitor.stopIt(win);
        }
      },
      {
        label: bundle.getString("processHang.button_wait.label"),
        accessKey: bundle.getString("processHang.button_wait.accessKey"),
        callback: function() {
          ProcessHangMonitor.waitLonger(win);
        }
      }];

    nb.appendNotification(bundle.getString("processHang.label"),
                          "process-hang",
                          "chrome://browser/content/aboutRobots-icon.png",
                          nb.PRIORITY_WARNING_HIGH, buttons);
  },

  /**
   * Ensure that no hang notifications are visible in |win|.
   */
  hideNotification: function(win) {
    let nb = win.document.getElementById("high-priority-global-notificationbox");
    let notification = nb.getNotificationWithValue("process-hang");
    if (notification) {
      nb.removeNotification(notification);
    }
  },

  /**
   * Install event handlers on |win| to watch for events that would
   * cause a different hang report to be displayed.
   */
  trackWindow: function(win) {
    win.gBrowser.tabContainer.addEventListener("TabSelect", this, true);
    win.gBrowser.tabContainer.addEventListener("TabRemotenessChange", this, true);
  },

  untrackWindow: function(win) {
    win.gBrowser.tabContainer.removeEventListener("TabSelect", this, true);
    win.gBrowser.tabContainer.removeEventListener("TabRemotenessChange", this, true);
  },

  handleEvent: function(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") {
      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: function(report) {
    // If this hang was already reported reset the timer for it.
    if (this._activeReports.has(report)) {
      // 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)) {
      return;
    }

    this._activeReports.add(report);
    this.updateWindows();
  },

  clearHang: function(report) {
    this.removeActiveReport(report);
    this.removePausedReport(report);
    report.userCanceled();
  },
};