The Tor Browser: mobile/android/chrome/content/MemoryObserver.js@fc2d59ddac77

     1 /* This Source Code Form is subject to the terms of the Mozilla Public

     2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,

     3  * You can obtain one at http://mozilla.org/MPL/2.0/. */

     4 "use strict";

     6 var MemoryObserver = {

     7   observe: function mo_observe(aSubject, aTopic, aData) {

     8     if (aTopic == "memory-pressure") {

     9       if (aData != "heap-minimize") {

    10         this.handleLowMemory();

    11       }

    12       // The JS engine would normally GC on this notification, but since we

    13       // disabled that in favor of this method (bug 669346), we should gc here.

    14       // See bug 784040 for when this code was ported from XUL to native Fennec.

    15       this.gc();

    16     } else if (aTopic == "Memory:Dump") {

    17       this.dumpMemoryStats(aData);

    18     }

    19   },

    21   handleLowMemory: function() {

    22     // do things to reduce memory usage here

    23     let tabs = BrowserApp.tabs;

    24     let selected = BrowserApp.selectedTab;

    25     for (let i = 0; i < tabs.length; i++) {

    26       if (tabs[i] != selected) {

    27         this.zombify(tabs[i]);

    28         Telemetry.addData("FENNEC_TAB_ZOMBIFIED", (Date.now() - tabs[i].lastTouchedAt) / 1000);

    29       }

    30     }

    31     Telemetry.addData("FENNEC_LOWMEM_TAB_COUNT", tabs.length);

    32   },

    34   zombify: function(tab) {

    35     let browser = tab.browser;

    36     let data = browser.__SS_data;

    37     let extra = browser.__SS_extdata;

    39     // We need this data to correctly create and position the new browser

    40     // If this browser is already a zombie, fallback to the session data

    41     let currentURL = browser.__SS_restore ? data.entries[0].url : browser.currentURI.spec;

    42     let sibling = browser.nextSibling;

    43     let isPrivate = PrivateBrowsingUtils.isWindowPrivate(browser.contentWindow);

    45     tab.destroy();

    46     tab.create(currentURL, { sibling: sibling, zombifying: true, delayLoad: true, isPrivate: isPrivate });

    48     // Reattach session store data and flag this browser so it is restored on select

    49     browser = tab.browser;

    50     browser.__SS_data = data;

    51     browser.__SS_extdata = extra;

    52     browser.__SS_restore = true;

    53     browser.setAttribute("pending", "true");

    54   },

    56   gc: function() {

    57     window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils).garbageCollect();

    58     Cu.forceGC();

    59   },

    61   dumpMemoryStats: function(aLabel) {

    62     let memDumper = Cc["@mozilla.org/memory-info-dumper;1"].getService(Ci.nsIMemoryInfoDumper);

    63     memDumper.dumpMemoryInfoToTempDir(aLabel, /* minimize = */ false);

    64   },

    65 };

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