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/* 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 MemoryObserver = {
observe: function mo_observe(aSubject, aTopic, aData) {
if (aTopic == "memory-pressure") {
if (aData != "heap-minimize") {
this.handleLowMemory();
}
// The JS engine would normally GC on this notification, but since we
// disabled that in favor of this method (bug 669346), we should gc here.
// See bug 784040 for when this code was ported from XUL to native Fennec.
this.gc();
} else if (aTopic == "Memory:Dump") {
this.dumpMemoryStats(aData);
}
},
handleLowMemory: function() {
// do things to reduce memory usage here
if (!Services.prefs.getBoolPref("browser.tabs.disableBackgroundZombification")) {
let tabs = BrowserApp.tabs;
let selected = BrowserApp.selectedTab;
for (let i = 0; i < tabs.length; i++) {
if (tabs[i] != selected && !tabs[i].playingAudio) {
this.zombify(tabs[i]);
}
}
}
// Change some preferences temporarily for only this session
let defaults = Services.prefs.getDefaultBranch(null);
// Reduce the amount of decoded image data we keep around
defaults.setIntPref("image.mem.max_decoded_image_kb", 0);
// Stop using the bfcache
if (!Services.prefs.getBoolPref("browser.sessionhistory.bfcacheIgnoreMemoryPressure")) {
defaults.setIntPref("browser.sessionhistory.max_total_viewers", 0);
}
},
zombify: function(tab) {
let browser = tab.browser;
let data = browser.__SS_data;
let extra = browser.__SS_extdata;
// Notify any interested parties (e.g. the session store)
// that the original tab object is going to be destroyed
let evt = document.createEvent("UIEvents");
evt.initUIEvent("TabPreZombify", true, false, window, null);
browser.dispatchEvent(evt);
// We need this data to correctly create and position the new browser
// If this browser is already a zombie, fallback to the session data
let currentURL = browser.__SS_restore ? data.entries[0].url : browser.currentURI.spec;
let sibling = browser.nextSibling;
let isPrivate = PrivateBrowsingUtils.isBrowserPrivate(browser);
tab.destroy();
tab.create(currentURL, { sibling: sibling, zombifying: true, delayLoad: true, isPrivate: isPrivate });
// Reattach session store data and flag this browser so it is restored on select
browser = tab.browser;
browser.__SS_data = data;
browser.__SS_extdata = extra;
browser.__SS_restore = true;
browser.setAttribute("pending", "true");
// Notify the session store to reattach its listeners to the new tab object
evt = document.createEvent("UIEvents");
evt.initUIEvent("TabPostZombify", true, false, window, null);
browser.dispatchEvent(evt);
},
gc: function() {
window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils).garbageCollect();
Cu.forceGC();
},
dumpMemoryStats: function(aLabel) {
let memDumper = Cc["@mozilla.org/memory-info-dumper;1"].getService(Ci.nsIMemoryInfoDumper);
memDumper.dumpMemoryInfoToTempDir(aLabel, /* anonymize = */ false,
/* minimize = */ false);
},
};
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