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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/. */

 "use strict";

 this.EXPORTED_SYMBOLS = ["SessionStorage"];

 const Cu = Components.utils;

 const Ci = Components.interfaces;

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

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

 XPCOMUtils.defineLazyModuleGetter(this, "console",

   "resource://gre/modules/devtools/Console.jsm");

 // Returns the principal for a given |frame| contained in a given |docShell|.

 function getPrincipalForFrame(docShell, frame) {

   let ssm = Services.scriptSecurityManager;

   let uri = frame.document.documentURIObject;

   return ssm.getDocShellCodebasePrincipal(uri, docShell);

 }

 this.SessionStorage = Object.freeze({

   /**

    * Updates all sessionStorage "super cookies"

    * @param docShell

    *        That tab's docshell (containing the sessionStorage)

    * @param frameTree

    *        The docShell's FrameTree instance.

    * @return Returns a nested object that will have hosts as keys and per-host

    *         session storage data as values. For example:

    *         {"example.com": {"key": "value", "my_number": 123}}

    */

   collect: function (docShell, frameTree) {

     return SessionStorageInternal.collect(docShell, frameTree);

   },

   /**

    * Restores all sessionStorage "super cookies".

    * @param aDocShell

    *        A tab's docshell (containing the sessionStorage)

    * @param aStorageData

    *        A nested object with storage data to be restored that has hosts as

    *        keys and per-host session storage data as values. For example:

    *        {"example.com": {"key": "value", "my_number": 123}}

    */

   restore: function (aDocShell, aStorageData) {

     SessionStorageInternal.restore(aDocShell, aStorageData);

   }

 });

 let SessionStorageInternal = {

   /**

    * Reads all session storage data from the given docShell.

    * @param docShell

    *        A tab's docshell (containing the sessionStorage)

    * @param frameTree

    *        The docShell's FrameTree instance.

    * @return Returns a nested object that will have hosts as keys and per-host

    *         session storage data as values. For example:

    *         {"example.com": {"key": "value", "my_number": 123}}

    */

   collect: function (docShell, frameTree) {

     let data = {};

     let visitedOrigins = new Set();

     frameTree.forEach(frame => {

       let principal = getPrincipalForFrame(docShell, frame);

       if (!principal) {

         return;

       }

       // Get the root domain of the current history entry

       // and use that as a key for the per-host storage data.

       let origin = principal.jarPrefix + principal.origin;

       if (visitedOrigins.has(origin)) {

         // Don't read a host twice.

         return;

       }

       // Mark the current origin as visited.

       visitedOrigins.add(origin);

       let originData = this._readEntry(principal, docShell);

       if (Object.keys(originData).length) {

         data[origin] = originData;

       }

     });

     return Object.keys(data).length ? data : null;

   },

   /**

    * Writes session storage data to the given tab.

    * @param aDocShell

    *        A tab's docshell (containing the sessionStorage)

    * @param aStorageData

    *        A nested object with storage data to be restored that has hosts as

    *        keys and per-host session storage data as values. For example:

    *        {"example.com": {"key": "value", "my_number": 123}}

    */

   restore: function (aDocShell, aStorageData) {

     for (let host of Object.keys(aStorageData)) {

       let data = aStorageData[host];

       let uri = Services.io.newURI(host, null, null);

       let principal = Services.scriptSecurityManager.getDocShellCodebasePrincipal(uri, aDocShell);

       let storageManager = aDocShell.QueryInterface(Ci.nsIDOMStorageManager);

       // There is no need to pass documentURI, it's only used to fill documentURI property of

       // domstorage event, which in this case has no consumer. Prevention of events in case

       // of missing documentURI will be solved in a followup bug to bug 600307.

       // TODO: We should call createStorageForFirstParty() here.  See comment

       //       inside _readEntry() for details.

       let storage = storageManager.createStorage(principal, "", aDocShell.usePrivateBrowsing);

       for (let key of Object.keys(data)) {

         try {

           storage.setItem(key, data[key]);

         } catch (e) {

           // throws e.g. for URIs that can't have sessionStorage

           console.error(e);

         }

       }

     }

   },

   /**

    * Reads an entry in the session storage data contained in a tab's history.

    * @param aURI

    *        That history entry uri

    * @param aDocShell

    *        A tab's docshell (containing the sessionStorage)

    */

   _readEntry: function (aPrincipal, aDocShell) {

     let hostData = {};

     let storage;

     try {

       let storageManager = aDocShell.QueryInterface(Ci.nsIDOMStorageManager);

       // TODO: We should call getStorageForFirstParty() here, but we need an

       //       nsIDocument to call thirdPartyUtil.getFirstPartyURI(), and

       //       unfortunately nsIDocument is not exposed to JavaScript.

       //       However, this code is not called in TBB because the

       //       browser.sessionstore.privacy_level pref. is set to 2.

       storage = storageManager.getStorage(aPrincipal);

     } catch (e) {

       // sessionStorage might throw if it's turned off, see bug 458954

     }

     if (storage && storage.length) {

        for (let i = 0; i < storage.length; i++) {

         try {

           let key = storage.key(i);

           hostData[key] = storage.getItem(key);

         } catch (e) {

           // This currently throws for secured items (cf. bug 442048).

         }

       }

     }

     return hostData;

   }

 };