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-rw-r--r--mobile/android/chrome/content/MemoryObserver.js88
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diff --git a/mobile/android/chrome/content/MemoryObserver.js b/mobile/android/chrome/content/MemoryObserver.js
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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);
+ },
+};