The Tor Browser / file revision

 /* 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/. */

 const { classes: Cc, interfaces: Ci, utils: Cu } = Components;

 Cu.import("resource://gre/modules/Accounts.jsm");

 Cu.import("resource://gre/modules/Services.jsm");

 Cu.import("resource://gre/modules/XPCOMUtils.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "Home", "resource://gre/modules/Home.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "OS", "resource://gre/modules/osfile.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "Task", "resource://gre/modules/Task.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "UITelemetry", "resource://gre/modules/UITelemetry.jsm");

 XPCOMUtils.defineLazyGetter(this, "gEncoder", function() { return new gChromeWin.TextEncoder(); });

 XPCOMUtils.defineLazyGetter(this, "gDecoder", function() { return new gChromeWin.TextDecoder(); });

 // URL to fetch snippets, in the urlFormatter service format.

 const SNIPPETS_UPDATE_URL_PREF = "browser.snippets.updateUrl";

 // URL to send stats data to metrics.

 const SNIPPETS_STATS_URL_PREF = "browser.snippets.statsUrl";

 // URL to fetch country code, a value that's cached and refreshed once per month.

 const SNIPPETS_GEO_URL_PREF = "browser.snippets.geoUrl";

 // Timestamp when we last updated the user's country code.

 const SNIPPETS_GEO_LAST_UPDATE_PREF = "browser.snippets.geoLastUpdate";

 // Pref where we'll cache the user's country.

 const SNIPPETS_COUNTRY_CODE_PREF = "browser.snippets.countryCode";

 // Pref where we store an array IDs of snippets that should not be shown again

 const SNIPPETS_REMOVED_IDS_PREF = "browser.snippets.removedIds";

 // How frequently we update the user's country code from the server (30 days).

 const SNIPPETS_GEO_UPDATE_INTERVAL_MS = 86400000*30;

 // Should be bumped up if the snippets content format changes.

 const SNIPPETS_VERSION = 1;

 XPCOMUtils.defineLazyGetter(this, "gSnippetsURL", function() {

   let updateURL = Services.prefs.getCharPref(SNIPPETS_UPDATE_URL_PREF).replace("%SNIPPETS_VERSION%", SNIPPETS_VERSION);

   return Services.urlFormatter.formatURL(updateURL);

 });

 // Where we cache snippets data

 XPCOMUtils.defineLazyGetter(this, "gSnippetsPath", function() {

   return OS.Path.join(OS.Constants.Path.profileDir, "snippets.json");

 });

 XPCOMUtils.defineLazyGetter(this, "gStatsURL", function() {

   return Services.prefs.getCharPref(SNIPPETS_STATS_URL_PREF);

 });

 // Where we store stats about which snippets have been shown

 XPCOMUtils.defineLazyGetter(this, "gStatsPath", function() {

   return OS.Path.join(OS.Constants.Path.profileDir, "snippets-stats.txt");

 });

 XPCOMUtils.defineLazyGetter(this, "gGeoURL", function() {

   return Services.prefs.getCharPref(SNIPPETS_GEO_URL_PREF);

 });

 XPCOMUtils.defineLazyGetter(this, "gCountryCode", function() {

   try {

     return Services.prefs.getCharPref(SNIPPETS_COUNTRY_CODE_PREF);

   } catch (e) {

     // Return an empty string if the country code pref isn't set yet.

     return "";

   }

 });

 XPCOMUtils.defineLazyGetter(this, "gChromeWin", function() {

   return Services.wm.getMostRecentWindow("navigator:browser");

 });

 /**

  * Updates snippet data and country code (if necessary).

  */

 function update() {

   // Check to see if we should update the user's country code from the geo server.

   let lastUpdate = 0;

   try {

     lastUpdate = parseFloat(Services.prefs.getCharPref(SNIPPETS_GEO_LAST_UPDATE_PREF));

   } catch (e) {}

   if (Date.now() - lastUpdate > SNIPPETS_GEO_UPDATE_INTERVAL_MS) {

     // We should update the snippets after updating the country code,

     // so that we can filter snippets to add to the banner.

     updateCountryCode(updateSnippets);

   } else {

     updateSnippets();

   }

 }

 /**

  * Fetches the user's country code from the geo server and stores the value in a pref.

  *

  * @param callback function called once country code is updated

  */

 function updateCountryCode(callback) {

   _httpGetRequest(gGeoURL, function(responseText) {

     // Store the country code in a pref.

     let data = JSON.parse(responseText);

     Services.prefs.setCharPref(SNIPPETS_COUNTRY_CODE_PREF, data.country_code);

     // Set last update time.

     Services.prefs.setCharPref(SNIPPETS_GEO_LAST_UPDATE_PREF, Date.now());

     callback();

   });

 }

 /**

  * Loads snippets from snippets server, caches the response, and

  * updates the home banner with the new set of snippets.

  */

 function updateSnippets() {

   _httpGetRequest(gSnippetsURL, function(responseText) {

     try {

       let messages = JSON.parse(responseText);

       updateBanner(messages);

       // Only cache the response if it is valid JSON.

       cacheSnippets(responseText);

     } catch (e) {

       Cu.reportError("Error parsing snippets responseText: " + e);

     }

   });

 }

 /**

  * Caches snippets server response text to `snippets.json` in profile directory.

  *

  * @param response responseText returned from snippets server

  */

 function cacheSnippets(response) {

   let data = gEncoder.encode(response);

   let promise = OS.File.writeAtomic(gSnippetsPath, data, { tmpPath: gSnippetsPath + ".tmp" });

   promise.then(null, e => Cu.reportError("Error caching snippets: " + e));

 }

 /**

  * Loads snippets from cached `snippets.json`.

  */

 function loadSnippetsFromCache() {

   let promise = OS.File.read(gSnippetsPath);

   promise.then(array => {

     let messages = JSON.parse(gDecoder.decode(array));

     updateBanner(messages);

   }, e => {

     if (e instanceof OS.File.Error && e.becauseNoSuchFile) {

       Services.console.logStringMessage("Couldn't show snippets because cache does not exist yet.");

     } else {

       Cu.reportError("Error loading snippets from cache: " + e);

     }

   });

 }

 // Array of the message ids added to the home banner, used to remove

 // older set of snippets when new ones are available.

 var gMessageIds = [];

 /**

  * Updates set of snippets in the home banner message rotation.

  *

  * @param messages JSON array of message data JSON objects.

  *   Each message object should have the following properties:

  *     - id (?): Unique identifier for this snippets message

  *     - text (string): Text to show as banner message

  *     - url (string): URL to open when banner is clicked

  *     - icon (data URI): Icon to appear in banner

  *     - target_geo (string): Country code for where this message should be shown (e.g. "US")

  */

 function updateBanner(messages) {

   // Remove the current messages, if there are any.

   gMessageIds.forEach(function(id) {

     Home.banner.remove(id);

   })

   gMessageIds = [];

   try {

     let removedSnippetIds = JSON.parse(Services.prefs.getCharPref(SNIPPETS_REMOVED_IDS_PREF));

     messages = messages.filter(function(message) {

       // Only include the snippet if it has not been previously removed.

       return removedSnippetIds.indexOf(message.id) === -1;

     });

   } catch (e) {

     // If the pref doesn't exist, there aren't any snippets to filter out.

   }

   messages.forEach(function(message) {

     // Don't add this message to the banner if it's not supposed to be shown in this country.

     if ("target_geo" in message && message.target_geo != gCountryCode) {

       return;

     }

     let id = Home.banner.add({

       text: message.text,

       icon: message.icon,

       onclick: function() {

         let parentId = gChromeWin.BrowserApp.selectedTab.id;

         gChromeWin.BrowserApp.addTab(message.url, { parentId: parentId });

         UITelemetry.addEvent("action.1", "banner", null, message.id);

       },

       ondismiss: function() {

         // Remove this snippet from the banner, and store its id so we'll never show it again.

         Home.banner.remove(id);

         removeSnippet(message.id);

         UITelemetry.addEvent("cancel.1", "banner", null, message.id);

       },

       onshown: function() {

         // 10% of the time, record the snippet id and a timestamp

         if (Math.random() < .1) {

           writeStat(message.id, new Date().toISOString());

         }

       }

     });

     // Keep track of the message we added so that we can remove it later.

     gMessageIds.push(id);

   });

 }

 /**

  * Appends snippet id to the end of `snippets-removed.txt`

  *

  * @param snippetId unique id for snippet, sent from snippets server

  */

 function removeSnippet(snippetId) {

   let removedSnippetIds;

   try {

     removedSnippetIds = JSON.parse(Services.prefs.getCharPref(SNIPPETS_REMOVED_IDS_PREF));

   } catch (e) {

     removedSnippetIds = [];

   }

   removedSnippetIds.push(snippetId);

   Services.prefs.setCharPref(SNIPPETS_REMOVED_IDS_PREF, JSON.stringify(removedSnippetIds));

 }

 /**

  * Appends snippet id and timestamp to the end of `snippets-stats.txt`.

  *

  * @param snippetId unique id for snippet, sent from snippets server

  * @param timestamp in ISO8601

  */

 function writeStat(snippetId, timestamp) {

   let data = gEncoder.encode(snippetId + "," + timestamp + ";");

   Task.spawn(function() {

     try {

       let file = yield OS.File.open(gStatsPath, { append: true, write: true });

       try {

         yield file.write(data);

       } finally {

         yield file.close();

       }

     } catch (ex if ex instanceof OS.File.Error && ex.becauseNoSuchFile) {

       // If the file doesn't exist yet, create it.

       yield OS.File.writeAtomic(gStatsPath, data, { tmpPath: gStatsPath + ".tmp" });

     }

   }).then(null, e => Cu.reportError("Error writing snippets stats: " + e));

 }

 /**

  * Reads snippets stats data from `snippets-stats.txt` and sends the data to metrics.

  */

 function sendStats() {

   let promise = OS.File.read(gStatsPath);

   promise.then(array => sendStatsRequest(gDecoder.decode(array)), e => {

     if (e instanceof OS.File.Error && e.becauseNoSuchFile) {

       // If the file doesn't exist, there aren't any stats to send.

     } else {

       Cu.reportError("Error eading snippets stats: " + e);

     }

   });

 }

 /**

  * Sends stats to metrics about which snippets have been shown.

  * Appends snippet ids and timestamps as parameters to a GET request.

  * e.g. https://snippets-stats.mozilla.org/mobile?s1=3825&t1=2013-11-17T18:27Z&s2=6326&t2=2013-11-18T18:27Z

  *

  * @param data contents of stats data file

  */

 function sendStatsRequest(data) {

   let params = [];

   let stats = data.split(";");

   // The last item in the array will be an empty string, so stop before then.

   for (let i = 0; i < stats.length - 1; i++) {

     let stat = stats[i].split(",");

     params.push("s" + i + "=" + encodeURIComponent(stat[0]));

     params.push("t" + i + "=" + encodeURIComponent(stat[1]));

   }

   let url = gStatsURL + "?" + params.join("&");

   // Remove the file after succesfully sending the data.

   _httpGetRequest(url, removeStats);

 }

 /**

  * Removes text file where we store snippets stats.

  */

 function removeStats() {

   let promise = OS.File.remove(gStatsPath);

   promise.then(null, e => Cu.reportError("Error removing snippets stats: " + e));

 }

 /**

  * Helper function to make HTTP GET requests.

  *

  * @param url where we send the request

  * @param callback function that is called with the xhr responseText

  */

 function _httpGetRequest(url, callback) {

   let xhr = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].createInstance(Ci.nsIXMLHttpRequest);

   try {

     xhr.open("GET", url, true);

   } catch (e) {

     Cu.reportError("Error opening request to " + url + ": " + e);

     return;

   }

   xhr.onerror = function onerror(e) {

     Cu.reportError("Error making request to " + url + ": " + e.error);

   }

   xhr.onload = function onload(event) {

     if (xhr.status !== 200) {

       Cu.reportError("Request to " + url + " returned status " + xhr.status);

       return;

     }

     if (callback) {

       callback(xhr.responseText);

     }

   }

   xhr.send(null);

 }

 function loadSyncPromoBanner() {

   Accounts.anySyncAccountsExist().then(

     (exist) => {

       // Don't show the banner if sync accounts exist.

       if (exist) {

         return;

       }

       let stringBundle = Services.strings.createBundle("chrome://browser/locale/sync.properties");

       let text = stringBundle.GetStringFromName("promoBanner.message.text");

       let link = stringBundle.GetStringFromName("promoBanner.message.link");

       let id = Home.banner.add({

         text: text + "<a href=\"#\">" + link + "</a>",

         icon: "drawable://sync_promo",

         onclick: function() {

           // Remove the message, so that it won't show again for the rest of the app lifetime.

           Home.banner.remove(id);

           Accounts.launchSetup();

           UITelemetry.addEvent("action.1", "banner", null, "syncpromo");

         },

         ondismiss: function() {

           // Remove the sync promo message from the banner and never try to show it again.

           Home.banner.remove(id);

           Services.prefs.setBoolPref("browser.snippets.syncPromo.enabled", false);

           UITelemetry.addEvent("cancel.1", "banner", null, "syncpromo");

         }

       });

     },

     (err) => {

       Cu.reportError("Error checking whether sync account exists: " + err);

     }

   );

 }

 function Snippets() {}

 Snippets.prototype = {

   QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver, Ci.nsITimerCallback]),

   classID: Components.ID("{a78d7e59-b558-4321-a3d6-dffe2f1e76dd}"),

   observe: function(subject, topic, data) {

     switch(topic) {

       case "profile-after-change":

         Services.obs.addObserver(this, "browser-delayed-startup-finished", false);

         break;

       case "browser-delayed-startup-finished":

         Services.obs.removeObserver(this, "browser-delayed-startup-finished", false);

         if (Services.prefs.getBoolPref("browser.snippets.syncPromo.enabled")) {

           loadSyncPromoBanner();

         }

         if (Services.prefs.getBoolPref("browser.snippets.enabled")) {

           loadSnippetsFromCache();

         }

         break;

     }

   },

   // By default, this timer fires once every 24 hours. See the "browser.snippets.updateInterval" pref.

   notify: function(timer) {

     if (!Services.prefs.getBoolPref("browser.snippets.enabled")) {

       return;

     }

     update();

     sendStats();

   }

 };

 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([Snippets]);