tor-browser

TaskbarTabsUtils.sys.mjs (5382B)

---

/* vim: se cin sw=2 ts=2 et filetype=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/. */

import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";

let lazy = {};

XPCOMUtils.defineLazyServiceGetters(lazy, {
 Favicons: ["@mozilla.org/browser/favicon-service;1", Ci.nsIFaviconService],
 imgTools: ["@mozilla.org/image/tools;1", Ci.imgITools],
});

ChromeUtils.defineLazyGetter(lazy, "logConsole", () => {
 return console.createInstance({
   prefix: "TaskbarTabs",
   maxLogLevel: "Warn",
 });
});

export const TaskbarTabsUtils = {
 /**
  * Checks if Taskbar Tabs has been enabled.
  *
  * @returns {bool} `true` if the Taskbar Tabs pref is enabled.
  */
 isEnabled() {
   const pref = "browser.taskbarTabs.enabled";
   return Services.prefs.getBoolPref(pref, false);
 },

 /**
  * Returns a folder to store profile-specific Taskbar Tabs files.
  *
  * @returns {nsIFile} Folder to store Taskbar Tabs files.
  */
 getTaskbarTabsFolder() {
   // Construct the path `[Profile]/taskbartabs/`.
   let folder = Services.dirsvc.get("ProfD", Ci.nsIFile);
   folder.append("taskbartabs");
   return folder;
 },

 /**
  * Checks if the window is a Taskbar Tabs window.
  *
  * @param {Window} aWin - The window to inspect.
  * @returns {bool} true if the window is a Taskbar Tabs window.
  */
 isTaskbarTabWindow(aWin) {
   return aWin.document.documentElement.hasAttribute("taskbartab");
 },

 /**
  * Retrieves the Taskbar Tabs ID for the window.
  *
  * @param {DOMWindow} aWin - The window to retrieve the Taskbar Tabs ID.
  * @returns {string} The Taskbar Tabs ID for the window.
  */
 getTaskbarTabIdFromWindow(aWin) {
   return aWin.document.documentElement.getAttribute("taskbartab");
 },

 /**
  * Retrieves a favicon image container for the provided URL.
  *
  * @param {nsIURI} aUri - The URI to retrieve a favicon for.
  * @returns {imgIContainer} A container of the favicon retrieved, or the
  * default favicon.
  */
 async getFavicon(aUri) {
   let favicon = await lazy.Favicons.getFaviconForPage(aUri);

   let imgContainer;
   if (favicon) {
     try {
       if (favicon.mimeType !== "image/svg+xml") {
         // Image containers retrieved via `getImageFromUri` error when
         // attempting to scale via `scaleImage`. Since we have the raw image
         // data from the favicon service and the image container decoded from
         // it scales without error, use it instead.
         let img = lazy.imgTools.decodeImageFromArrayBuffer(
           new Uint8Array(favicon.rawData).buffer,
           favicon.mimeType
         );
         imgContainer = scaleImage(img);
       } else {
         // `imgITools::decodeImage*` APIs don't work with SVG images.
         imgContainer = getImageFromUri(favicon.dataURI);
       }
     } catch (e) {
       lazy.logConsole.error(
         `${e.message}, falling through to default favicon.`
       );
     }
   }

   if (!imgContainer) {
     lazy.logConsole.debug(
       `Unable to retrieve icon for ${aUri.spec}, using default favicon at ${lazy.Favicons.defaultFavicon.spec}.`
     );
     imgContainer = await getImageFromUri(lazy.Favicons.defaultFavicon);
   }

   return imgContainer;
 },
};

/**
* Attempts to scale the provided image container to a 256x256 image.
*
* @param {imgIContainer} aImgContainer - The image container to scale from.
* @returns {imgIContainer} The scaled image container on success, or the
* provided image container on failure.
*/
function scaleImage(aImgContainer) {
 try {
   const istream = lazy.imgTools.encodeScaledImage(
     aImgContainer,
     "image/png",
     256,
     256
   );
   const size = istream.available();

   // Use a binary input stream to grab the bytes.
   const bis = Cc["@mozilla.org/binaryinputstream;1"].createInstance(
     Ci.nsIBinaryInputStream
   );
   bis.setInputStream(istream);

   const bytes = bis.readBytes(size);
   if (size != bytes.length) {
     throw new Error("Didn't read expected number of bytes");
   }
   aImgContainer = lazy.imgTools.decodeImageFromBuffer(
     bytes,
     bytes.length,
     "image/png"
   );
 } catch (e) {
   lazy.logConsole.error(
     "Failed to scale the favicon image, continuing with the unscaled image container."
   );
 }

 return aImgContainer;
}

/**
* Retrieves an image given a URI.
*
* @param {nsIURI} aUri - The URI to retrieve an image from.
* @returns {Promise<imgIContainer>} Resolves to an image container.
*/
async function getImageFromUri(aUri) {
 // Creating the Taskbar Tabs icon should not result in a network request.
 const protocolFlags = Services.io.getProtocolFlags(aUri.scheme);
 if (!(protocolFlags & Ci.nsIProtocolHandler.URI_IS_LOCAL_RESOURCE)) {
   throw new Error(
     `Scheme "${aUri.scheme}" is not supported for creating a Taskbar Tab icon, URI should be local`
   );
 }

 const channel = Services.io.newChannelFromURI(
   aUri,
   null,
   Services.scriptSecurityManager.getSystemPrincipal(),
   null,
   Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
   Ci.nsIContentPolicy.TYPE_IMAGE
 );

 return ChromeUtils.fetchDecodedImage(aUri, channel);
}