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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/. */
+
+/**
+ * Controls the "full zoom" setting and its site-specific preferences.
+ */
+var FullZoom = {
+ // Identifies the setting in the content prefs database.
+ name: "browser.content.full-zoom",
+
+ // browser.zoom.siteSpecific preference cache
+ _siteSpecificPref: undefined,
+
+ // browser.zoom.updateBackgroundTabs preference cache
+ updateBackgroundTabs: undefined,
+
+ // This maps the browser to monotonically increasing integer
+ // tokens. _browserTokenMap[browser] is increased each time the zoom is
+ // changed in the browser. See _getBrowserToken and _ignorePendingZoomAccesses.
+ _browserTokenMap: new WeakMap(),
+
+ // Stores initial locations if we receive onLocationChange
+ // events before we're initialized.
+ _initialLocations: new WeakMap(),
+
+ get siteSpecific() {
+ return this._siteSpecificPref;
+ },
+
+ // nsISupports
+
+ QueryInterface: XPCOMUtils.generateQI([Ci.nsIDOMEventListener,
+ Ci.nsIObserver,
+ Ci.nsIContentPrefObserver,
+ Ci.nsISupportsWeakReference,
+ Ci.nsISupports]),
+
+ // Initialization & Destruction
+
+ init: function FullZoom_init() {
+ gBrowser.addEventListener("ZoomChangeUsingMouseWheel", this);
+
+ // Register ourselves with the service so we know when our pref changes.
+ this._cps2 = Cc["@mozilla.org/content-pref/service;1"].
+ getService(Ci.nsIContentPrefService2);
+ this._cps2.addObserverForName(this.name, this);
+
+ this._siteSpecificPref =
+ gPrefService.getBoolPref("browser.zoom.siteSpecific");
+ this.updateBackgroundTabs =
+ gPrefService.getBoolPref("browser.zoom.updateBackgroundTabs");
+ // Listen for changes to the browser.zoom branch so we can enable/disable
+ // updating background tabs and per-site saving and restoring of zoom levels.
+ gPrefService.addObserver("browser.zoom.", this, true);
+
+ // If we received onLocationChange events for any of the current browsers
+ // before we were initialized we want to replay those upon initialization.
+ for (let browser of gBrowser.browsers) {
+ if (this._initialLocations.has(browser)) {
+ this.onLocationChange(...this._initialLocations.get(browser), browser);
+ }
+ }
+
+ // This should be nulled after initialization.
+ this._initialLocations = null;
+ },
+
+ destroy: function FullZoom_destroy() {
+ gPrefService.removeObserver("browser.zoom.", this);
+ this._cps2.removeObserverForName(this.name, this);
+ gBrowser.removeEventListener("ZoomChangeUsingMouseWheel", this);
+ },
+
+
+ // Event Handlers
+
+ // nsIDOMEventListener
+
+ handleEvent: function FullZoom_handleEvent(event) {
+ switch (event.type) {
+ case "ZoomChangeUsingMouseWheel":
+ let browser = this._getTargetedBrowser(event);
+ this._ignorePendingZoomAccesses(browser);
+ this._applyZoomToPref(browser);
+ break;
+ }
+ },
+
+ // nsIObserver
+
+ observe: function (aSubject, aTopic, aData) {
+ switch (aTopic) {
+ case "nsPref:changed":
+ switch (aData) {
+ case "browser.zoom.siteSpecific":
+ this._siteSpecificPref =
+ gPrefService.getBoolPref("browser.zoom.siteSpecific");
+ break;
+ case "browser.zoom.updateBackgroundTabs":
+ this.updateBackgroundTabs =
+ gPrefService.getBoolPref("browser.zoom.updateBackgroundTabs");
+ break;
+ }
+ break;
+ }
+ },
+
+ // nsIContentPrefObserver
+
+ onContentPrefSet: function FullZoom_onContentPrefSet(aGroup, aName, aValue, aIsPrivate) {
+ this._onContentPrefChanged(aGroup, aValue, aIsPrivate);
+ },
+
+ onContentPrefRemoved: function FullZoom_onContentPrefRemoved(aGroup, aName, aIsPrivate) {
+ this._onContentPrefChanged(aGroup, undefined, aIsPrivate);
+ },
+
+ /**
+ * Appropriately updates the zoom level after a content preference has
+ * changed.
+ *
+ * @param aGroup The group of the changed preference.
+ * @param aValue The new value of the changed preference. Pass undefined to
+ * indicate the preference's removal.
+ */
+ _onContentPrefChanged: function FullZoom__onContentPrefChanged(aGroup, aValue, aIsPrivate) {
+ if (this._isNextContentPrefChangeInternal) {
+ // Ignore changes that FullZoom itself makes. This works because the
+ // content pref service calls callbacks before notifying observers, and it
+ // does both in the same turn of the event loop.
+ delete this._isNextContentPrefChangeInternal;
+ return;
+ }
+
+ let browser = gBrowser.selectedBrowser;
+ if (!browser.currentURI)
+ return;
+
+ let ctxt = this._loadContextFromBrowser(browser);
+ let domain = this._cps2.extractDomain(browser.currentURI.spec);
+ if (aGroup) {
+ if (aGroup == domain && ctxt.usePrivateBrowsing == aIsPrivate)
+ this._applyPrefToZoom(aValue, browser);
+ return;
+ }
+
+ this._globalValue = aValue === undefined ? aValue :
+ this._ensureValid(aValue);
+
+ // If the current page doesn't have a site-specific preference, then its
+ // zoom should be set to the new global preference now that the global
+ // preference has changed.
+ let hasPref = false;
+ let token = this._getBrowserToken(browser);
+ this._cps2.getByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
+ handleResult: function () { hasPref = true; },
+ handleCompletion: function () {
+ if (!hasPref && token.isCurrent)
+ this._applyPrefToZoom(undefined, browser);
+ }.bind(this)
+ });
+ },
+
+ // location change observer
+
+ /**
+ * Called when the location of a tab changes.
+ * When that happens, we need to update the current zoom level if appropriate.
+ *
+ * @param aURI
+ * A URI object representing the new location.
+ * @param aIsTabSwitch
+ * Whether this location change has happened because of a tab switch.
+ * @param aBrowser
+ * (optional) browser object displaying the document
+ */
+ onLocationChange: function FullZoom_onLocationChange(aURI, aIsTabSwitch, aBrowser) {
+ let browser = aBrowser || gBrowser.selectedBrowser;
+
+ // If we haven't been initialized yet but receive an onLocationChange
+ // notification then let's store and replay it upon initialization.
+ if (this._initialLocations) {
+ this._initialLocations.set(browser, [aURI, aIsTabSwitch]);
+ return;
+ }
+
+ // Ignore all pending async zoom accesses in the browser. Pending accesses
+ // that started before the location change will be prevented from applying
+ // to the new location.
+ this._ignorePendingZoomAccesses(browser);
+
+ if (!aURI || (aIsTabSwitch && !this.siteSpecific)) {
+ this._notifyOnLocationChange(browser);
+ return;
+ }
+
+ // Avoid the cps roundtrip and apply the default/global pref.
+ if (aURI.spec == "about:blank") {
+ this._applyPrefToZoom(undefined, browser,
+ this._notifyOnLocationChange.bind(this, browser));
+ return;
+ }
+
+ // Media documents should always start at 1, and are not affected by prefs.
+ if (!aIsTabSwitch && browser.isSyntheticDocument) {
+ ZoomManager.setZoomForBrowser(browser, 1);
+ // _ignorePendingZoomAccesses already called above, so no need here.
+ this._notifyOnLocationChange(browser);
+ return;
+ }
+
+ // See if the zoom pref is cached.
+ let ctxt = this._loadContextFromBrowser(browser);
+ let pref = this._cps2.getCachedByDomainAndName(aURI.spec, this.name, ctxt);
+ if (pref) {
+ this._applyPrefToZoom(pref.value, browser,
+ this._notifyOnLocationChange.bind(this, browser));
+ return;
+ }
+
+ // It's not cached, so we have to asynchronously fetch it.
+ let value = undefined;
+ let token = this._getBrowserToken(browser);
+ this._cps2.getByDomainAndName(aURI.spec, this.name, ctxt, {
+ handleResult: function (resultPref) { value = resultPref.value; },
+ handleCompletion: function () {
+ if (!token.isCurrent) {
+ this._notifyOnLocationChange(browser);
+ return;
+ }
+ this._applyPrefToZoom(value, browser,
+ this._notifyOnLocationChange.bind(this, browser));
+ }.bind(this)
+ });
+ },
+
+ // update state of zoom type menu item
+
+ updateMenu: function FullZoom_updateMenu() {
+ var menuItem = document.getElementById("toggle_zoom");
+
+ menuItem.setAttribute("checked", !ZoomManager.useFullZoom);
+ },
+
+ // Setting & Pref Manipulation
+
+ /**
+ * Reduces the zoom level of the page in the current browser.
+ */
+ reduce: function FullZoom_reduce() {
+ ZoomManager.reduce();
+ let browser = gBrowser.selectedBrowser;
+ this._ignorePendingZoomAccesses(browser);
+ this._applyZoomToPref(browser);
+ },
+
+ /**
+ * Enlarges the zoom level of the page in the current browser.
+ */
+ enlarge: function FullZoom_enlarge() {
+ ZoomManager.enlarge();
+ let browser = gBrowser.selectedBrowser;
+ this._ignorePendingZoomAccesses(browser);
+ this._applyZoomToPref(browser);
+ },
+
+ /**
+ * Sets the zoom level for the given browser to the given floating
+ * point value, where 1 is the default zoom level.
+ */
+ setZoom: function (value, browser = gBrowser.selectedBrowser) {
+ ZoomManager.setZoomForBrowser(browser, value);
+ this._ignorePendingZoomAccesses(browser);
+ this._applyZoomToPref(browser);
+ },
+
+ /**
+ * Sets the zoom level of the page in the given browser to the global zoom
+ * level.
+ *
+ * @return A promise which resolves when the zoom reset has been applied.
+ */
+ reset: function FullZoom_reset(browser = gBrowser.selectedBrowser) {
+ let token = this._getBrowserToken(browser);
+ let result = this._getGlobalValue(browser).then(value => {
+ if (token.isCurrent) {
+ ZoomManager.setZoomForBrowser(browser, value === undefined ? 1 : value);
+ this._ignorePendingZoomAccesses(browser);
+ Services.obs.notifyObservers(browser, "browser-fullZoom:zoomReset", "");
+ }
+ });
+ this._removePref(browser);
+ return result;
+ },
+
+ /**
+ * Set the zoom level for a given browser.
+ *
+ * Per nsPresContext::setFullZoom, we can set the zoom to its current value
+ * without significant impact on performance, as the setting is only applied
+ * if it differs from the current setting. In fact getting the zoom and then
+ * checking ourselves if it differs costs more.
+ *
+ * And perhaps we should always set the zoom even if it was more expensive,
+ * since nsDocumentViewer::SetTextZoom claims that child documents can have
+ * a different text zoom (although it would be unusual), and it implies that
+ * those child text zooms should get updated when the parent zoom gets set,
+ * and perhaps the same is true for full zoom
+ * (although nsDocumentViewer::SetFullZoom doesn't mention it).
+ *
+ * So when we apply new zoom values to the browser, we simply set the zoom.
+ * We don't check first to see if the new value is the same as the current
+ * one.
+ *
+ * @param aValue The zoom level value.
+ * @param aBrowser The zoom is set in this browser. Required.
+ * @param aCallback If given, it's asynchronously called when complete.
+ */
+ _applyPrefToZoom: function FullZoom__applyPrefToZoom(aValue, aBrowser, aCallback) {
+ if (!this.siteSpecific || gInPrintPreviewMode) {
+ this._executeSoon(aCallback);
+ return;
+ }
+
+ // The browser is sometimes half-destroyed because this method is called
+ // by content pref service callbacks, which themselves can be called at any
+ // time, even after browsers are closed.
+ if (!aBrowser.parentNode || aBrowser.isSyntheticDocument) {
+ this._executeSoon(aCallback);
+ return;
+ }
+
+ if (aValue !== undefined) {
+ ZoomManager.setZoomForBrowser(aBrowser, this._ensureValid(aValue));
+ this._ignorePendingZoomAccesses(aBrowser);
+ this._executeSoon(aCallback);
+ return;
+ }
+
+ let token = this._getBrowserToken(aBrowser);
+ this._getGlobalValue(aBrowser).then(value => {
+ if (token.isCurrent) {
+ ZoomManager.setZoomForBrowser(aBrowser, value === undefined ? 1 : value);
+ this._ignorePendingZoomAccesses(aBrowser);
+ }
+ this._executeSoon(aCallback);
+ });
+ },
+
+ /**
+ * Saves the zoom level of the page in the given browser to the content
+ * prefs store.
+ *
+ * @param browser The zoom of this browser will be saved. Required.
+ */
+ _applyZoomToPref: function FullZoom__applyZoomToPref(browser) {
+ Services.obs.notifyObservers(browser, "browser-fullZoom:zoomChange", "");
+ if (!this.siteSpecific ||
+ gInPrintPreviewMode ||
+ browser.isSyntheticDocument)
+ return;
+
+ this._cps2.set(browser.currentURI.spec, this.name,
+ ZoomManager.getZoomForBrowser(browser),
+ this._loadContextFromBrowser(browser), {
+ handleCompletion: function () {
+ this._isNextContentPrefChangeInternal = true;
+ }.bind(this),
+ });
+ },
+
+ /**
+ * Removes from the content prefs store the zoom level of the given browser.
+ *
+ * @param browser The zoom of this browser will be removed. Required.
+ */
+ _removePref: function FullZoom__removePref(browser) {
+ Services.obs.notifyObservers(browser, "browser-fullZoom:zoomReset", "");
+ if (browser.isSyntheticDocument)
+ return;
+ let ctxt = this._loadContextFromBrowser(browser);
+ this._cps2.removeByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
+ handleCompletion: function () {
+ this._isNextContentPrefChangeInternal = true;
+ }.bind(this),
+ });
+ },
+
+ // Utilities
+
+ /**
+ * Returns the zoom change token of the given browser. Asynchronous
+ * operations that access the given browser's zoom should use this method to
+ * capture the token before starting and use token.isCurrent to determine if
+ * it's safe to access the zoom when done. If token.isCurrent is false, then
+ * after the async operation started, either the browser's zoom was changed or
+ * the browser was destroyed, and depending on what the operation is doing, it
+ * may no longer be safe to set and get its zoom.
+ *
+ * @param browser The token of this browser will be returned.
+ * @return An object with an "isCurrent" getter.
+ */
+ _getBrowserToken: function FullZoom__getBrowserToken(browser) {
+ let map = this._browserTokenMap;
+ if (!map.has(browser))
+ map.set(browser, 0);
+ return {
+ token: map.get(browser),
+ get isCurrent() {
+ // At this point, the browser may have been destructed and unbound but
+ // its outer ID not removed from the map because outer-window-destroyed
+ // hasn't been received yet. In that case, the browser is unusable, it
+ // has no properties, so return false. Check for this case by getting a
+ // property, say, docShell.
+ return map.get(browser) === this.token && browser.parentNode;
+ },
+ };
+ },
+
+ /**
+ * Returns the browser that the supplied zoom event is associated with.
+ * @param event The ZoomChangeUsingMouseWheel event.
+ * @return The associated browser element, if one exists, otherwise null.
+ */
+ _getTargetedBrowser: function FullZoom__getTargetedBrowser(event) {
+ let target = event.originalTarget;
+
+ // With remote content browsers, the event's target is the browser
+ // we're looking for.
+ const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+ if (target instanceof window.XULElement &&
+ target.localName == "browser" &&
+ target.namespaceURI == XUL_NS)
+ return target;
+
+ // With in-process content browsers, the event's target is the content
+ // document.
+ if (target.nodeType == Node.DOCUMENT_NODE)
+ return gBrowser.getBrowserForDocument(target);
+
+ throw new Error("Unexpected ZoomChangeUsingMouseWheel event source");
+ },
+
+ /**
+ * Increments the zoom change token for the given browser so that pending
+ * async operations know that it may be unsafe to access they zoom when they
+ * finish.
+ *
+ * @param browser Pending accesses in this browser will be ignored.
+ */
+ _ignorePendingZoomAccesses: function FullZoom__ignorePendingZoomAccesses(browser) {
+ let map = this._browserTokenMap;
+ map.set(browser, (map.get(browser) || 0) + 1);
+ },
+
+ _ensureValid: function FullZoom__ensureValid(aValue) {
+ // Note that undefined is a valid value for aValue that indicates a known-
+ // not-to-exist value.
+ if (isNaN(aValue))
+ return 1;
+
+ if (aValue < ZoomManager.MIN)
+ return ZoomManager.MIN;
+
+ if (aValue > ZoomManager.MAX)
+ return ZoomManager.MAX;
+
+ return aValue;
+ },
+
+ /**
+ * Gets the global browser.content.full-zoom content preference.
+ *
+ * @param browser The browser pertaining to the zoom.
+ * @returns Promise<prefValue>
+ * Resolves to the preference value when done.
+ */
+ _getGlobalValue: function FullZoom__getGlobalValue(browser) {
+ // * !("_globalValue" in this) => global value not yet cached.
+ // * this._globalValue === undefined => global value known not to exist.
+ // * Otherwise, this._globalValue is a number, the global value.
+ return new Promise(resolve => {
+ if ("_globalValue" in this) {
+ resolve(this._globalValue);
+ return;
+ }
+ let value = undefined;
+ this._cps2.getGlobal(this.name, this._loadContextFromBrowser(browser), {
+ handleResult: function (pref) { value = pref.value; },
+ handleCompletion: (reason) => {
+ this._globalValue = this._ensureValid(value);
+ resolve(this._globalValue);
+ }
+ });
+ });
+ },
+
+ /**
+ * Gets the load context from the given Browser.
+ *
+ * @param Browser The Browser whose load context will be returned.
+ * @return The nsILoadContext of the given Browser.
+ */
+ _loadContextFromBrowser: function FullZoom__loadContextFromBrowser(browser) {
+ return browser.loadContext;
+ },
+
+ /**
+ * Asynchronously broadcasts "browser-fullZoom:location-change" so that
+ * listeners can be notified when the zoom levels on those pages change.
+ * The notification is always asynchronous so that observers are guaranteed a
+ * consistent behavior.
+ */
+ _notifyOnLocationChange: function FullZoom__notifyOnLocationChange(browser) {
+ this._executeSoon(function () {
+ Services.obs.notifyObservers(browser, "browser-fullZoom:location-change", "");
+ });
+ },
+
+ _executeSoon: function FullZoom__executeSoon(callback) {
+ if (!callback)
+ return;
+ Services.tm.mainThread.dispatch(callback, Ci.nsIThread.DISPATCH_NORMAL);
+ },
+};
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