gecko-dev/browser/base/content/browser-fullZoom.js

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JavaScript

/* 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/. */
// This file is loaded into the browser window scope.
/* eslint-env mozilla/browser-window */
/**
* 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
// Enabling privacy.resistFingerprinting implies disabling browser.zoom.siteSpecific.
_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() {
if (this._siteSpecificPref === undefined) {
this._siteSpecificPref =
!Services.prefs.getBoolPref("privacy.resistFingerprinting") &&
Services.prefs.getBoolPref("browser.zoom.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.updateBackgroundTabs =
Services.prefs.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.
Services.prefs.addObserver("browser.zoom.", this, true);
// Also need to listen to privacy.resistFingerprinting in order to update
// this._siteSpecificPref.
Services.prefs.addObserver("privacy.resistFingerprinting", 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() {
Services.prefs.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(aSubject, aTopic, aData) {
switch (aTopic) {
case "nsPref:changed":
switch (aData) {
case "privacy.resistFingerprinting":
// fall through
case "browser.zoom.siteSpecific":
// Invalidate pref cache.
this._siteSpecificPref = undefined;
break;
case "browser.zoom.updateBackgroundTabs":
this.updateBackgroundTabs =
Services.prefs.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() { hasPref = true; },
handleCompletion: () => {
if (!hasPref && token.isCurrent)
this._applyPrefToZoom(undefined, browser);
}
});
},
// 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(resultPref) { value = resultPref.value; },
handleCompletion: () => {
if (!token.isCurrent) {
this._notifyOnLocationChange(browser);
return;
}
this._applyPrefToZoom(value, browser,
this._notifyOnLocationChange.bind(this, browser));
}
});
},
// 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(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);
}
});
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) {
if (!this.siteSpecific ||
gInPrintPreviewMode ||
browser.isSyntheticDocument)
return;
this._cps2.set(browser.currentURI.spec, this.name,
ZoomManager.getZoomForBrowser(browser),
this._loadContextFromBrowser(browser), {
handleCompletion: () => {
this._isNextContentPrefChangeInternal = true;
},
});
},
/**
* 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) {
if (browser.isSyntheticDocument)
return;
let ctxt = this._loadContextFromBrowser(browser);
this._cps2.removeByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
handleCompletion: () => {
this._isNextContentPrefChangeInternal = true;
},
});
},
// 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(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.dispatchToMainThread(callback);
},
};