Merge pull request #998 from MoonchildProductions/master

Merge master into Sync-weave

1 files changed, 961 insertions, 0 deletions

diff --git a/toolkit/mozapps/extensions/GMPInstallManager.jsm b/toolkit/mozapps/extensions/GMPInstallManager.jsm
new file mode 100644
index 000000000..b9ebe5d7e
--- /dev/null
+++ b/toolkit/mozapps/extensions/GMPInstallManager.jsm
@@ -0,0 +1,961 @@
+/* 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";
+
+this.EXPORTED_SYMBOLS = [];
+
+const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu, manager: Cm} =
+  Components;
+// Chunk size for the incremental downloader
+const DOWNLOAD_CHUNK_BYTES_SIZE = 300000;
+// Incremental downloader interval
+const DOWNLOAD_INTERVAL  = 0;
+// 1 day default
+const DEFAULT_SECONDS_BETWEEN_CHECKS = 60 * 60 * 24;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/FileUtils.jsm");
+Cu.import("resource://gre/modules/Promise.jsm");
+Cu.import("resource://gre/modules/Preferences.jsm");
+Cu.import("resource://gre/modules/Log.jsm");
+Cu.import("resource://gre/modules/osfile.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://gre/modules/ctypes.jsm");
+Cu.import("resource://gre/modules/GMPUtils.jsm");
+
+this.EXPORTED_SYMBOLS = ["GMPInstallManager", "GMPExtractor", "GMPDownloader",
+                         "GMPAddon"];
+
+var gLocale = null;
+
+// Shared code for suppressing bad cert dialogs
+XPCOMUtils.defineLazyGetter(this, "gCertUtils", function() {
+  let temp = { };
+  Cu.import("resource://gre/modules/CertUtils.jsm", temp);
+  return temp;
+});
+
+XPCOMUtils.defineLazyModuleGetter(this, "UpdateChannel",
+                                  "resource://gre/modules/UpdateChannel.jsm");
+
+/**
+ * Number of milliseconds after which we need to cancel `checkForAddons`.
+ *
+ * Bug 1087674 suggests that the XHR we use in `checkForAddons` may
+ * never terminate in presence of network nuisances (e.g. strange
+ * antivirus behavior). This timeout is a defensive measure to ensure
+ * that we fail cleanly in such case.
+ */
+const CHECK_FOR_ADDONS_TIMEOUT_DELAY_MS = 20000;
+
+function getScopedLogger(prefix) {
+  // `PARENT_LOGGER_ID.` being passed here effectively links this logger
+  // to the parentLogger.
+  return Log.repository.getLoggerWithMessagePrefix("Toolkit.GMP", prefix + " ");
+}
+
+// This is copied directly from nsUpdateService.js
+// It is used for calculating the URL string w/ var replacement.
+// TODO: refactor this out somewhere else
+XPCOMUtils.defineLazyGetter(this, "gOSVersion", function aus_gOSVersion() {
+  let osVersion;
+  let sysInfo = Cc["@mozilla.org/system-info;1"].
+                getService(Ci.nsIPropertyBag2);
+  try {
+    osVersion = sysInfo.getProperty("name") + " " + sysInfo.getProperty("version");
+  }
+  catch (e) {
+    LOG("gOSVersion - OS Version unknown: updates are not possible.");
+  }
+
+  if (osVersion) {
+#ifdef XP_WIN
+    const BYTE = ctypes.uint8_t;
+    const WORD = ctypes.uint16_t;
+    const DWORD = ctypes.uint32_t;
+    const WCHAR = ctypes.char16_t;
+    const BOOL = ctypes.int;
+
+    // This structure is described at:
+    // http://msdn.microsoft.com/en-us/library/ms724833%28v=vs.85%29.aspx
+    const SZCSDVERSIONLENGTH = 128;
+    const OSVERSIONINFOEXW = new ctypes.StructType('OSVERSIONINFOEXW',
+        [
+        {dwOSVersionInfoSize: DWORD},
+        {dwMajorVersion: DWORD},
+        {dwMinorVersion: DWORD},
+        {dwBuildNumber: DWORD},
+        {dwPlatformId: DWORD},
+        {szCSDVersion: ctypes.ArrayType(WCHAR, SZCSDVERSIONLENGTH)},
+        {wServicePackMajor: WORD},
+        {wServicePackMinor: WORD},
+        {wSuiteMask: WORD},
+        {wProductType: BYTE},
+        {wReserved: BYTE}
+        ]);
+
+    // This structure is described at:
+    // http://msdn.microsoft.com/en-us/library/ms724958%28v=vs.85%29.aspx
+    const SYSTEM_INFO = new ctypes.StructType('SYSTEM_INFO',
+        [
+        {wProcessorArchitecture: WORD},
+        {wReserved: WORD},
+        {dwPageSize: DWORD},
+        {lpMinimumApplicationAddress: ctypes.voidptr_t},
+        {lpMaximumApplicationAddress: ctypes.voidptr_t},
+        {dwActiveProcessorMask: DWORD.ptr},
+        {dwNumberOfProcessors: DWORD},
+        {dwProcessorType: DWORD},
+        {dwAllocationGranularity: DWORD},
+        {wProcessorLevel: WORD},
+        {wProcessorRevision: WORD}
+        ]);
+
+    let kernel32 = false;
+    try {
+      kernel32 = ctypes.open("Kernel32");
+    } catch (e) {
+      LOG("gOSVersion - Unable to open kernel32! " + e);
+      osVersion += ".unknown (unknown)";
+    }
+
+    if(kernel32) {
+      try {
+        // Get Service pack info
+        try {
+          let GetVersionEx = kernel32.declare("GetVersionExW",
+                                              ctypes.default_abi,
+                                              BOOL,
+                                              OSVERSIONINFOEXW.ptr);
+          let winVer = OSVERSIONINFOEXW();
+          winVer.dwOSVersionInfoSize = OSVERSIONINFOEXW.size;
+
+          if(0 !== GetVersionEx(winVer.address())) {
+            osVersion += "." + winVer.wServicePackMajor
+                      +  "." + winVer.wServicePackMinor;
+          } else {
+            LOG("gOSVersion - Unknown failure in GetVersionEX (returned 0)");
+            osVersion += ".unknown";
+          }
+        } catch (e) {
+          LOG("gOSVersion - error getting service pack information. Exception: " + e);
+          osVersion += ".unknown";
+        }
+
+        // Get processor architecture
+        let arch = "unknown";
+        try {
+          let GetNativeSystemInfo = kernel32.declare("GetNativeSystemInfo",
+                                                     ctypes.default_abi,
+                                                     ctypes.void_t,
+                                                     SYSTEM_INFO.ptr);
+          let sysInfo = SYSTEM_INFO();
+          // Default to unknown
+          sysInfo.wProcessorArchitecture = 0xffff;
+
+          GetNativeSystemInfo(sysInfo.address());
+          switch(sysInfo.wProcessorArchitecture) {
+            case 9:
+              arch = "x64";
+              break;
+            case 6:
+              arch = "IA64";
+              break;
+            case 0:
+              arch = "x86";
+              break;
+          }
+        } catch (e) {
+          LOG("gOSVersion - error getting processor architecture.  Exception: " + e);
+        } finally {
+          osVersion += " (" + arch + ")";
+        }
+      } finally {
+        kernel32.close();
+      }
+    }
+#endif
+
+    try {
+      osVersion += " (" + sysInfo.getProperty("secondaryLibrary") + ")";
+    }
+    catch (e) {
+      // Not all platforms have a secondary widget library, so an error is nothing to worry about.
+    }
+    osVersion = encodeURIComponent(osVersion);
+  }
+  return osVersion;
+});
+
+// This is copied directly from nsUpdateService.js
+// It is used for calculating the URL string w/ var replacement.
+// TODO: refactor this out somewhere else
+XPCOMUtils.defineLazyGetter(this, "gABI", function aus_gABI() {
+  let abi = null;
+  try {
+    abi = Services.appinfo.XPCOMABI;
+  }
+  catch (e) {
+    LOG("gABI - XPCOM ABI unknown: updates are not possible.");
+  }
+#ifdef XP_MACOSX
+  // Mac universal build should report a different ABI than either macppc
+  // or mactel.
+  let macutils = Cc["@mozilla.org/xpcom/mac-utils;1"].
+                 getService(Ci.nsIMacUtils);
+
+  if (macutils.isUniversalBinary)
+    abi += "-u-" + macutils.architecturesInBinary;
+#ifdef MOZ_SHARK
+  // Disambiguate optimised and shark nightlies
+  abi += "-shark"
+#endif
+#endif
+  return abi;
+});
+
+/**
+ * Provides an easy API for downloading and installing GMP Addons
+ */
+function GMPInstallManager() {
+}
+/**
+ * Temp file name used for downloading
+ */
+GMPInstallManager.prototype = {
+  /**
+   * Obtains a URL with replacement of vars
+   */
+  _getURL: function() {
+    let log = getScopedLogger("GMPInstallManager._getURL");
+    // Use the override URL if it is specified.  The override URL is just like
+    // the normal URL but it does not check the cert.
+    let url = GMPPrefs.get(GMPPrefs.KEY_URL_OVERRIDE);
+    if (url) {
+      log.info("Using override url: " + url);
+    } else {
+      url = GMPPrefs.get(GMPPrefs.KEY_URL);
+      log.info("Using url: " + url);
+    }
+
+    url =
+      url.replace(/%PRODUCT%/g, Services.appinfo.name)
+         .replace(/%VERSION%/g, Services.appinfo.version)
+         .replace(/%BUILD_ID%/g, Services.appinfo.appBuildID)
+         .replace(/%BUILD_TARGET%/g, Services.appinfo.OS + "_" + gABI)
+         .replace(/%OS_VERSION%/g, gOSVersion);
+    if (/%LOCALE%/.test(url)) {
+      // TODO: Get the real local, does it actually matter for GMP plugins?
+      url = url.replace(/%LOCALE%/g, "en-US");
+    }
+    url =
+      url.replace(/%CHANNEL%/g, UpdateChannel.get())
+         .replace(/%PLATFORM_VERSION%/g, Services.appinfo.platformVersion)
+         .replace(/%DISTRIBUTION%/g,
+                  GMPPrefs.get(GMPPrefs.KEY_APP_DISTRIBUTION))
+         .replace(/%DISTRIBUTION_VERSION%/g,
+                  GMPPrefs.get(GMPPrefs.KEY_APP_DISTRIBUTION_VERSION))
+         .replace(/\+/g, "%2B");
+    log.info("Using url (with replacement): " + url);
+    return url;
+  },
+  /**
+   * Performs an addon check.
+   * @return a promise which will be resolved or rejected.
+   *         The promise is resolved with an array of GMPAddons
+   *         The promise is rejected with an object with properties:
+   *           target: The XHR request object
+   *           status: The HTTP status code
+   *           type: Sometimes specifies type of rejection
+   */
+  checkForAddons: function() {
+    let log = getScopedLogger("GMPInstallManager.checkForAddons");
+    if (this._deferred) {
+        log.error("checkForAddons already called");
+        return Promise.reject({type: "alreadycalled"});
+    }
+    this._deferred = Promise.defer();
+    let url = this._getURL();
+
+    this._request = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].
+                    createInstance(Ci.nsISupports);
+    // This is here to let unit test code override XHR
+    if (this._request.wrappedJSObject) {
+      this._request = this._request.wrappedJSObject;
+    }
+    this._request.open("GET", url, true);
+    let allowNonBuiltIn = !GMPPrefs.get(GMPPrefs.KEY_CERT_CHECKATTRS, true);
+    this._request.channel.notificationCallbacks =
+      new gCertUtils.BadCertHandler(allowNonBuiltIn);
+    // Prevent the request from reading from the cache.
+    this._request.channel.loadFlags |= Ci.nsIRequest.LOAD_BYPASS_CACHE;
+    // Prevent the request from writing to the cache.
+    this._request.channel.loadFlags |= Ci.nsIRequest.INHIBIT_CACHING;
+
+    this._request.overrideMimeType("text/xml");
+    // The Cache-Control header is only interpreted by proxies and the
+    // final destination. It does not help if a resource is already
+    // cached locally.
+    this._request.setRequestHeader("Cache-Control", "no-cache");
+    // HTTP/1.0 servers might not implement Cache-Control and
+    // might only implement Pragma: no-cache
+    this._request.setRequestHeader("Pragma", "no-cache");
+
+    this._request.timeout = CHECK_FOR_ADDONS_TIMEOUT_DELAY_MS;
+    this._request.addEventListener("error", event => this.onFailXML("onErrorXML", event), false);
+    this._request.addEventListener("abort", event => this.onFailXML("onAbortXML", event), false);
+    this._request.addEventListener("timeout", event => this.onFailXML("onTimeoutXML", event), false);
+    this._request.addEventListener("load", event => this.onLoadXML(event), false);
+
+    log.info("sending request to: " + url);
+    this._request.send(null);
+
+    return this._deferred.promise;
+  },
+  /**
+   * Installs the specified addon and calls a callback when done.
+   * @param gmpAddon The GMPAddon object to install
+   * @return a promise which will be resolved or rejected
+   *         The promise will resolve with an array of paths that were extracted
+   *         The promise will reject with an error object:
+   *           target: The XHR request object
+   *           status: The HTTP status code
+   *           type: A string to represent the type of error
+   *                 downloaderr, verifyerr or previouserrorencountered
+   */
+  installAddon: function(gmpAddon) {
+    if (this._deferred) {
+        log.error("previous error encountered");
+        return Promise.reject({type: "previouserrorencountered"});
+    }
+    this.gmpDownloader = new GMPDownloader(gmpAddon);
+    return this.gmpDownloader.start();
+  },
+  _getTimeSinceLastCheck: function() {
+    let now = Math.round(Date.now() / 1000);
+    // Default to 0 here because `now - 0` will be returned later if that case
+    // is hit. We want a large value so a check will occur.
+    let lastCheck = GMPPrefs.get(GMPPrefs.KEY_UPDATE_LAST_CHECK, 0);
+    // Handle clock jumps, return now since we want it to represent
+    // a lot of time has passed since the last check.
+    if (now < lastCheck) {
+      return now;
+    }
+    return now - lastCheck;
+  },
+  get _isEMEEnabled() {
+    return GMPPrefs.get(GMPPrefs.KEY_EME_ENABLED, true);
+  },
+  _isAddonUpdateEnabled: function(aAddon) {
+    return GMPPrefs.get(GMPPrefs.KEY_PLUGIN_ENABLED, true, aAddon) &&
+           GMPPrefs.get(GMPPrefs.KEY_PLUGIN_AUTOUPDATE, true, aAddon);
+  },
+  _updateLastCheck: function() {
+    let now = Math.round(Date.now() / 1000);
+    GMPPrefs.set(GMPPrefs.KEY_UPDATE_LAST_CHECK, now);
+  },
+  _versionchangeOccurred: function() {
+    let savedBuildID = GMPPrefs.get(GMPPrefs.KEY_BUILDID, null);
+    let buildID = Services.appinfo.platformBuildID;
+    if (savedBuildID == buildID) {
+      return false;
+    }
+    GMPPrefs.set(GMPPrefs.KEY_BUILDID, buildID);
+    return true;
+  },
+  /**
+   * Wrapper for checkForAddons and installAddon.
+   * Will only install if not already installed and will log the results.
+   * This will only install/update the OpenH264 and EME plugins
+   * @return a promise which will be resolved if all addons could be installed
+   *         successfully, rejected otherwise.
+   */
+  simpleCheckAndInstall: Task.async(function*() {
+    let log = getScopedLogger("GMPInstallManager.simpleCheckAndInstall");
+
+    if (this._versionchangeOccurred()) {
+      log.info("A version change occurred. Ignoring " +
+               "media.gmp-manager.lastCheck to check immediately for " +
+               "new or updated GMPs.");
+    } else {
+      let secondsBetweenChecks =
+        GMPPrefs.get(GMPPrefs.KEY_SECONDS_BETWEEN_CHECKS,
+                     DEFAULT_SECONDS_BETWEEN_CHECKS)
+      let secondsSinceLast = this._getTimeSinceLastCheck();
+      log.info("Last check was: " + secondsSinceLast +
+               " seconds ago, minimum seconds: " + secondsBetweenChecks);
+      if (secondsBetweenChecks > secondsSinceLast) {
+        log.info("Will not check for updates.");
+        return {status: "too-frequent-no-check"};
+      }
+    }
+
+    try {
+      let gmpAddons = yield this.checkForAddons();
+      this._updateLastCheck();
+      log.info("Found " + gmpAddons.length + " addons advertised.");
+      let addonsToInstall = gmpAddons.filter(function(gmpAddon) {
+        log.info("Found addon: " + gmpAddon.toString());
+
+        if (!gmpAddon.isValid || GMPUtils.isPluginHidden(gmpAddon) ||
+            gmpAddon.isInstalled) {
+          log.info("Addon invalid, hidden or already installed.");
+          return false;
+        }
+
+        let addonUpdateEnabled = false;
+        if (GMP_PLUGIN_IDS.indexOf(gmpAddon.id) >= 0) {
+          addonUpdateEnabled = this._isAddonUpdateEnabled(gmpAddon.id);
+          if (!addonUpdateEnabled) {
+            log.info("Auto-update is off for " + gmpAddon.id +
+                     ", skipping check.");
+          }
+        } else {
+          // Currently, we only support installs of OpenH264 and EME plugins.
+          log.info("Auto-update is off for unknown plugin '" + gmpAddon.id +
+                   "', skipping check.");
+        }
+
+        return addonUpdateEnabled;
+      }, this);
+
+      if (!addonsToInstall.length) {
+        log.info("No new addons to install, returning");
+        return {status: "nothing-new-to-install"};
+      }
+
+      let installResults = [];
+      let failureEncountered = false;
+      for (let addon of addonsToInstall) {
+        try {
+          yield this.installAddon(addon);
+          installResults.push({
+            id:     addon.id,
+            result: "succeeded",
+          });
+        } catch (e) {
+          failureEncountered = true;
+          installResults.push({
+            id:     addon.id,
+            result: "failed",
+          });
+        }
+      }
+      if (failureEncountered) {
+        throw {status:  "failed",
+               results: installResults};
+      }
+      return {status:  "succeeded",
+              results: installResults};
+    } catch(e) {
+      log.error("Could not check for addons", e);
+      throw e;
+    }
+  }),
+
+  /**
+   * Makes sure everything is cleaned up
+   */
+  uninit: function() {
+    let log = getScopedLogger("GMPInstallManager.uninit");
+    if (this._request) {
+      log.info("Aborting request");
+      this._request.abort();
+    }
+    if (this._deferred) {
+        log.info("Rejecting deferred");
+        this._deferred.reject({type: "uninitialized"});
+    }
+    log.info("Done cleanup");
+  },
+
+  /**
+   * If set to true, specifies to leave the temporary downloaded zip file.
+   * This is useful for tests.
+   */
+  overrideLeaveDownloadedZip: false,
+
+  /**
+   * The XMLHttpRequest succeeded and the document was loaded.
+   * @param event The nsIDOMEvent for the load
+  */
+  onLoadXML: function(event) {
+    let log = getScopedLogger("GMPInstallManager.onLoadXML");
+    try {
+      log.info("request completed downloading document");
+      let certs = null;
+      if (!Services.prefs.prefHasUserValue(GMPPrefs.KEY_URL_OVERRIDE) &&
+          GMPPrefs.get(GMPPrefs.KEY_CERT_CHECKATTRS, true)) {
+        certs = gCertUtils.readCertPrefs(GMPPrefs.KEY_CERTS_BRANCH);
+      }
+
+      let allowNonBuiltIn = !GMPPrefs.get(GMPPrefs.KEY_CERT_REQUIREBUILTIN,
+                                          true);
+      log.info("allowNonBuiltIn: " + allowNonBuiltIn);
+
+      gCertUtils.checkCert(this._request.channel, allowNonBuiltIn, certs);
+
+      this.parseResponseXML();
+    } catch (ex) {
+      log.error("could not load xml: " + ex);
+      this._deferred.reject({
+        target: event.target,
+        status: this._getChannelStatus(event.target),
+        message: "" + ex,
+      });
+      delete this._deferred;
+    }
+  },
+
+  /**
+   * Returns the status code for the XMLHttpRequest
+   */
+  _getChannelStatus: function(request) {
+    let log = getScopedLogger("GMPInstallManager._getChannelStatus");
+    let status = null;
+    try {
+      status = request.status;
+      log.info("request.status is: " + request.status);
+    }
+    catch (e) {
+    }
+
+    if (status == null) {
+      status = request.channel.QueryInterface(Ci.nsIRequest).status;
+    }
+    return status;
+  },
+
+  /**
+   * There was an error of some kind during the XMLHttpRequest.  This
+   * error may have been caused by external factors (e.g. network
+   * issues) or internally (by a timeout).
+   *
+   * @param event The nsIDOMEvent for the error
+   */
+  onFailXML: function(failure, event) {
+    let log = getScopedLogger("GMPInstallManager.onFailXML " + failure);
+    let request = event.target;
+    let status = this._getChannelStatus(request);
+    let message = "request.status: " + status +  " (" + event.type + ")";
+    log.warn(message);
+    this._deferred.reject({
+      target: request,
+      status: status,
+      message: message
+    });
+    delete this._deferred;
+  },
+
+  /**
+   * Returns an array of GMPAddon objects discovered by the update check.
+   * Or returns an empty array if there were any problems with parsing.
+   * If there's an error, it will be logged if logging is enabled.
+   */
+  parseResponseXML: function() {
+    try {
+      let log = getScopedLogger("GMPInstallManager.parseResponseXML");
+      let updatesElement = this._request.responseXML.documentElement;
+      if (!updatesElement) {
+        let message = "empty updates document";
+        log.warn(message);
+        this._deferred.reject({
+          target: this._request,
+          message: message
+        });
+        delete this._deferred;
+        return;
+      }
+
+      if (updatesElement.nodeName != "updates") {
+        let message = "got node name: " + updatesElement.nodeName +
+          ", expected: updates";
+        log.warn(message);
+        this._deferred.reject({
+          target: this._request,
+          message: message
+        });
+        delete this._deferred;
+        return;
+      }
+
+      const ELEMENT_NODE = Ci.nsIDOMNode.ELEMENT_NODE;
+      let gmpResults = [];
+      for (let i = 0; i < updatesElement.childNodes.length; ++i) {
+        let updatesChildElement = updatesElement.childNodes.item(i);
+        if (updatesChildElement.nodeType != ELEMENT_NODE) {
+          continue;
+        }
+        if (updatesChildElement.localName == "addons") {
+          gmpResults = GMPAddon.parseGMPAddonsNode(updatesChildElement);
+        }
+      }
+      this._deferred.resolve(gmpResults);
+      delete this._deferred;
+    } catch (e) {
+      this._deferred.reject({
+        target: this._request,
+        message: e
+      });
+      delete this._deferred;
+    }
+  },
+};
+
+/**
+ * Used to construct a single GMP addon
+ * GMPAddon objects are returns from GMPInstallManager.checkForAddons
+ * GMPAddon objects can also be used in calls to GMPInstallManager.installAddon
+ *
+ * @param gmpAddon The AUS response XML's DOM element `addon`
+ */
+function GMPAddon(gmpAddon) {
+  let log = getScopedLogger("GMPAddon.constructor");
+  gmpAddon.QueryInterface(Ci.nsIDOMElement);
+  ["id", "URL", "hashFunction",
+   "hashValue", "version", "size"].forEach(name => {
+    if (gmpAddon.hasAttribute(name)) {
+      this[name] = gmpAddon.getAttribute(name);
+    }
+  });
+  this.size = Number(this.size) || undefined;
+  log.info ("Created new addon: " + this.toString());
+}
+/**
+ * Parses an XML GMP addons node from AUS into an array
+ * @param addonsElement An nsIDOMElement compatible node with XML from AUS
+ * @return An array of GMPAddon results
+ */
+GMPAddon.parseGMPAddonsNode = function(addonsElement) {
+  let log = getScopedLogger("GMPAddon.parseGMPAddonsNode");
+  let gmpResults = [];
+  if (addonsElement.localName !== "addons") {
+    return;
+  }
+
+  addonsElement.QueryInterface(Ci.nsIDOMElement);
+  let addonCount = addonsElement.childNodes.length;
+  for (let i = 0; i < addonCount; ++i) {
+    let addonElement = addonsElement.childNodes.item(i);
+    if (addonElement.localName !== "addon") {
+      continue;
+    }
+    addonElement.QueryInterface(Ci.nsIDOMElement);
+    try {
+      gmpResults.push(new GMPAddon(addonElement));
+    } catch (e) {
+      log.warn("invalid addon: " + e);
+      continue;
+    }
+  }
+  return gmpResults;
+};
+GMPAddon.prototype = {
+  /**
+   * Returns a string representation of the addon
+   */
+  toString: function() {
+    return this.id + " (" +
+           "isValid: " + this.isValid +
+           ", isInstalled: " + this.isInstalled +
+           ", hashFunction: " + this.hashFunction+
+           ", hashValue: " + this.hashValue +
+           (this.size !== undefined ? ", size: " + this.size : "" ) +
+           ")";
+  },
+  /**
+   * If all the fields aren't specified don't consider this addon valid
+   * @return true if the addon is parsed and valid
+   */
+  get isValid() {
+    return this.id && this.URL && this.version &&
+      this.hashFunction && !!this.hashValue;
+  },
+  get isInstalled() {
+    return this.version &&
+      GMPPrefs.get(GMPPrefs.KEY_PLUGIN_VERSION, "", this.id) === this.version;
+  },
+  get isEME() {
+    return this.id == "gmp-widevinecdm" || this.id.indexOf("gmp-eme-") == 0;
+  },
+};
+/**
+ * Constructs a GMPExtractor object which is used to extract a GMP zip
+ * into the specified location. (Which typically leties per platform)
+ * @param zipPath The path on disk of the zip file to extract
+ */
+function GMPExtractor(zipPath, installToDirPath) {
+    this.zipPath = zipPath;
+    this.installToDirPath = installToDirPath;
+}
+GMPExtractor.prototype = {
+  /**
+   * Obtains a list of all the entries in a zipfile in the format of *.*.
+   * This also includes files inside directories.
+   *
+   * @param zipReader the nsIZipReader to check
+   * @return An array of string name entries which can be used
+   *         in nsIZipReader.extract
+   */
+  _getZipEntries: function(zipReader) {
+    let entries = [];
+    let enumerator = zipReader.findEntries("*.*");
+    while (enumerator.hasMore()) {
+      entries.push(enumerator.getNext());
+    }
+    return entries;
+  },
+  /**
+   * Installs the this.zipPath contents into the directory used to store GMP
+   * addons for the current platform.
+   *
+   * @return a promise which will be resolved or rejected
+   *         See GMPInstallManager.installAddon for resolve/rejected info
+   */
+  install: function() {
+    try {
+      let log = getScopedLogger("GMPExtractor.install");
+      this._deferred = Promise.defer();
+      log.info("Installing " + this.zipPath + "...");
+      // Get the input zip file
+      let zipFile = Cc["@mozilla.org/file/local;1"].
+                    createInstance(Ci.nsIFile);
+      zipFile.initWithPath(this.zipPath);
+
+      // Initialize a zipReader and obtain the entries
+      var zipReader = Cc["@mozilla.org/libjar/zip-reader;1"].
+                      createInstance(Ci.nsIZipReader);
+      zipReader.open(zipFile)
+      let entries = this._getZipEntries(zipReader);
+      let extractedPaths = [];
+
+      // Extract each of the entries
+      entries.forEach(entry => {
+        // We don't need these types of files
+        if (entry.includes("__MACOSX")) {
+          return;
+        }
+        let outFile = Cc["@mozilla.org/file/local;1"].
+                      createInstance(Ci.nsILocalFile);
+        outFile.initWithPath(this.installToDirPath);
+        outFile.appendRelativePath(entry);
+
+        // Make sure the directory hierarchy exists
+        if(!outFile.parent.exists()) {
+          outFile.parent.create(Ci.nsIFile.DIRECTORY_TYPE, parseInt("0755", 8));
+        }
+        zipReader.extract(entry, outFile);
+        extractedPaths.push(outFile.path);
+        log.info(entry + " was successfully extracted to: " +
+            outFile.path);
+      });
+      zipReader.close();
+      if (!GMPInstallManager.overrideLeaveDownloadedZip) {
+        zipFile.remove(false);
+      }
+
+      log.info(this.zipPath + " was installed successfully");
+      this._deferred.resolve(extractedPaths);
+    } catch (e) {
+      if (zipReader) {
+        zipReader.close();
+      }
+      this._deferred.reject({
+        target: this,
+        status: e,
+        type: "exception"
+      });
+    }
+    return this._deferred.promise;
+  }
+};
+
+
+/**
+ * Constructs an object which downloads and initiates an install of
+ * the specified GMPAddon object.
+ * @param gmpAddon The addon to install.
+ */
+function GMPDownloader(gmpAddon)
+{
+  this._gmpAddon = gmpAddon;
+}
+/**
+ * Computes the file hash of fileToHash with the specified hash function
+ * @param hashFunctionName A hash function name such as sha512
+ * @param fileToHash An nsIFile to hash
+ * @return a promise which resolve to a digest in binary hex format
+ */
+GMPDownloader.computeHash = function(hashFunctionName, fileToHash) {
+  let log = getScopedLogger("GMPDownloader.computeHash");
+  let digest;
+  let fileStream = Cc["@mozilla.org/network/file-input-stream;1"].
+                   createInstance(Ci.nsIFileInputStream);
+  fileStream.init(fileToHash, FileUtils.MODE_RDONLY,
+                  FileUtils.PERMS_FILE, 0);
+  try {
+    let hash = Cc["@mozilla.org/security/hash;1"].
+               createInstance(Ci.nsICryptoHash);
+    let hashFunction =
+      Ci.nsICryptoHash[hashFunctionName.toUpperCase()];
+    if (!hashFunction) {
+      log.error("could not get hash function");
+      return Promise.reject();
+    }
+    hash.init(hashFunction);
+    hash.updateFromStream(fileStream, -1);
+    digest = binaryToHex(hash.finish(false));
+  } catch (e) {
+    log.warn("failed to compute hash: " + e);
+    digest = "";
+  }
+  fileStream.close();
+  return Promise.resolve(digest);
+},
+GMPDownloader.prototype = {
+  /**
+   * Starts the download process for an addon.
+   * @return a promise which will be resolved or rejected
+   *         See GMPInstallManager.installAddon for resolve/rejected info
+   */
+  start: function() {
+    let log = getScopedLogger("GMPDownloader.start");
+    this._deferred = Promise.defer();
+    if (!this._gmpAddon.isValid) {
+      log.info("gmpAddon is not valid, will not continue");
+      return Promise.reject({
+        target: this,
+        status: status,
+        type: "downloaderr"
+      });
+    }
+
+    let uri = Services.io.newURI(this._gmpAddon.URL, null, null);
+    this._request = Cc["@mozilla.org/network/incremental-download;1"].
+                    createInstance(Ci.nsIIncrementalDownload);
+    let gmpFile = FileUtils.getFile("TmpD", [this._gmpAddon.id + ".zip"]);
+    if (gmpFile.exists()) {
+      gmpFile.remove(false);
+    }
+
+    log.info("downloading from " + uri.spec + " to " + gmpFile.path);
+    this._request.init(uri, gmpFile, DOWNLOAD_CHUNK_BYTES_SIZE,
+                       DOWNLOAD_INTERVAL);
+    this._request.start(this, null);
+    return this._deferred.promise;
+  },
+  // For nsIRequestObserver
+  onStartRequest: function(request, context) {
+  },
+  // For nsIRequestObserver
+  // Called when the GMP addon zip file is downloaded
+  onStopRequest: function(request, context, status) {
+    let log = getScopedLogger("GMPDownloader.onStopRequest");
+    log.info("onStopRequest called");
+    if (!Components.isSuccessCode(status)) {
+      log.info("status failed: " + status);
+      this._deferred.reject({
+        target: this,
+        status: status,
+        type: "downloaderr"
+      });
+      return;
+    }
+
+    let promise = this._verifyDownload();
+    promise.then(() => {
+      log.info("GMP file is ready to unzip");
+      let destination = this._request.destination;
+
+      let zipPath = destination.path;
+      let gmpAddon = this._gmpAddon;
+      let installToDirPath = Cc["@mozilla.org/file/local;1"].
+                          createInstance(Ci.nsIFile);
+      let path = OS.Path.join(OS.Constants.Path.profileDir,
+                              gmpAddon.id,
+                              gmpAddon.version);
+      installToDirPath.initWithPath(path);
+      log.info("install to directory path: " + installToDirPath.path);
+      let gmpInstaller = new GMPExtractor(zipPath, installToDirPath.path);
+      let installPromise = gmpInstaller.install();
+      installPromise.then(extractedPaths => {
+        // Success, set the prefs
+        let now = Math.round(Date.now() / 1000);
+        GMPPrefs.set(GMPPrefs.KEY_PLUGIN_LAST_UPDATE, now, gmpAddon.id);
+        // Setting the version pref signals installation completion to consumers,
+        // if you need to set other prefs etc. do it before this.
+        GMPPrefs.set(GMPPrefs.KEY_PLUGIN_VERSION, gmpAddon.version,
+                     gmpAddon.id);
+        this._deferred.resolve(extractedPaths);
+      }, err => {
+        this._deferred.reject(err);
+      });
+    }, err => {
+      log.warn("verifyDownload check failed");
+      this._deferred.reject({
+        target: this,
+        status: 200,
+        type: "verifyerr"
+      });
+    });
+  },
+  /**
+   * Verifies that the downloaded zip file's hash matches the GMPAddon hash.
+   * @return a promise which resolves if the download verifies
+   */
+  _verifyDownload: function() {
+    let verifyDownloadDeferred = Promise.defer();
+    let log = getScopedLogger("GMPDownloader._verifyDownload");
+    log.info("_verifyDownload called");
+    if (!this._request) {
+      return Promise.reject();
+    }
+
+    let destination = this._request.destination;
+    log.info("for path: " + destination.path);
+
+    // Ensure that the file size matches the expected file size.
+    if (this._gmpAddon.size !== undefined &&
+        destination.fileSize != this._gmpAddon.size) {
+      log.warn("Downloader:_verifyDownload downloaded size " +
+               destination.fileSize + " != expected size " +
+               this._gmpAddon.size + ".");
+      return Promise.reject();
+    }
+
+    let promise = GMPDownloader.computeHash(this._gmpAddon.hashFunction, destination);
+    promise.then(digest => {
+        let expectedDigest = this._gmpAddon.hashValue.toLowerCase();
+        if (digest !== expectedDigest) {
+          log.warn("hashes do not match! Got: `" +
+                   digest + "`, expected: `" + expectedDigest +  "`");
+          this._deferred.reject();
+          return;
+        }
+
+        log.info("hashes match!");
+        verifyDownloadDeferred.resolve();
+    }, err => {
+        verifyDownloadDeferred.reject();
+    });
+    return verifyDownloadDeferred.promise;
+  },
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsIRequestObserver])
+};
+
+/**
+ * Convert a string containing binary values to hex.
+ */
+function binaryToHex(input) {
+  let result = "";
+  for (let i = 0; i < input.length; ++i) {
+    let hex = input.charCodeAt(i).toString(16);
+    if (hex.length == 1)
+      hex = "0" + hex;
+    result += hex;
+  }
+  return result;
+}