The Tor Browser: dom/settings/SettingsDB.jsm@97036ab72558 (annotated)

dom/settings/SettingsDB.jsm@97036ab72558 (annotated)

dom/settings/SettingsDB.jsm

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* 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";
 let Cc = Components.classes;
 let Ci = Components.interfaces;
 let Cu = Components.utils;
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/ObjectWrapper.jsm");
 this.EXPORTED_SYMBOLS = ["SettingsDB", "SETTINGSDB_NAME", "SETTINGSSTORE_NAME"];
 const DEBUG = false;
 function debug(s) {
   if (DEBUG) dump("-*- SettingsDB: " + s + "\n");
 }
 this.SETTINGSDB_NAME = "settings";
 this.SETTINGSDB_VERSION = 3;
 this.SETTINGSSTORE_NAME = "settings";
 Cu.import("resource://gre/modules/IndexedDBHelper.jsm");
 Cu.import("resource://gre/modules/FileUtils.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 this.SettingsDB = function SettingsDB() {}
 SettingsDB.prototype = {
   __proto__: IndexedDBHelper.prototype,
   upgradeSchema: function upgradeSchema(aTransaction, aDb, aOldVersion, aNewVersion) {
     let objectStore;
     if (aOldVersion == 0) {
       objectStore = aDb.createObjectStore(SETTINGSSTORE_NAME, { keyPath: "settingName" });
       if (DEBUG) debug("Created object stores");
     } else if (aOldVersion == 1) {
       if (DEBUG) debug("Get object store for upgrade and remove old index");
       objectStore = aTransaction.objectStore(SETTINGSSTORE_NAME);
       objectStore.deleteIndex("settingValue");
     } else {
       if (DEBUG) debug("Get object store for upgrade");
       objectStore = aTransaction.objectStore(SETTINGSSTORE_NAME);
     }
     // Loading resource://app/defaults/settings.json doesn't work because
     // settings.json is not in the omnijar.
     // So we look for the app dir instead and go from here...
     let settingsFile = FileUtils.getFile("DefRt", ["settings.json"], false);
     if (!settingsFile || (settingsFile && !settingsFile.exists())) {
       // On b2g desktop builds the settings.json file is moved in the
       // profile directory by the build system.
       settingsFile = FileUtils.getFile("ProfD", ["settings.json"], false);
       if (!settingsFile || (settingsFile && !settingsFile.exists())) {
         return;
       }
     }
     let chan = NetUtil.newChannel(settingsFile);
     let stream = chan.open();
     // Obtain a converter to read from a UTF-8 encoded input stream.
     let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
                     .createInstance(Ci.nsIScriptableUnicodeConverter);
     converter.charset = "UTF-8";
     let rawstr = converter.ConvertToUnicode(NetUtil.readInputStreamToString(
                                             stream,
                                             stream.available()) || "");
     let settings;
     try {
       settings = JSON.parse(rawstr);
     } catch(e) {
       if (DEBUG) debug("Error parsing " + settingsFile.path + " : " + e);
       return;
     }
     stream.close();
     objectStore.openCursor().onsuccess = function(event) {
       let cursor = event.target.result;
       if (cursor) {
         let value = cursor.value;
         if (value.settingName in settings) {
           if (DEBUG) debug("Upgrade " +settings[value.settingName]);
           value.defaultValue = this.prepareValue(settings[value.settingName]);
           delete settings[value.settingName];
           if ("settingValue" in value) {
             value.userValue = this.prepareValue(value.settingValue);
             delete value.settingValue;
           }
           cursor.update(value);
         } else if ("userValue" in value || "settingValue" in value) {
           value.defaultValue = undefined;
           if (aOldVersion == 1 && value.settingValue) {
             value.userValue = this.prepareValue(value.settingValue);
             delete value.settingValue;
           }
           cursor.update(value);
         } else {
           cursor.delete();
         }
         cursor.continue();
       } else {
         for (let name in settings) {
           let value = this.prepareValue(settings[name]);
           if (DEBUG) debug("Set new:" + name +", " + value);
           objectStore.add({ settingName: name, defaultValue: value, userValue: undefined });
         }
       }
     }.bind(this);
   },
   // If the value is a data: uri, convert it to a Blob.
   convertDataURIToBlob: function(aValue) {
     /* base64 to ArrayBuffer decoding, from
        https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding
     */
     function b64ToUint6 (nChr) {
       return nChr > 64 && nChr < 91 ?
           nChr - 65
         : nChr > 96 && nChr < 123 ?
           nChr - 71
         : nChr > 47 && nChr < 58 ?
           nChr + 4
         : nChr === 43 ?
 
         : nChr === 47 ?
 
         :
 ;
     }
     function base64DecToArr(sBase64, nBlocksSize) {
       let sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""),
           nInLen = sB64Enc.length,
           nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize
                                 : nInLen * 3 + 1 >> 2,
           taBytes = new Uint8Array(nOutLen);
       for (let nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
         nMod4 = nInIdx & 3;
         nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;
         if (nMod4 === 3 || nInLen - nInIdx === 1) {
           for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
             taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
           }
           nUint24 = 0;
         }
       }
       return taBytes;
     }
     // Check if we have a data: uri, and if it's base64 encoded.
     // data:image/jpeg;base64,/9j/4AAQSkZJRgABAQEA...
     if (typeof aValue == "string" && aValue.startsWith("data:")) {
       try {
         let uri = Services.io.newURI(aValue, null, null);
         // XXX: that would be nice to reuse the c++ bits of the data:
         // protocol handler instead.
         let mimeType = "application/octet-stream";
         let mimeDelim = aValue.indexOf(";");
         if (mimeDelim !== -1) {
           mimeType = aValue.substring(5, mimeDelim);
         }
         let start = aValue.indexOf(",") + 1;
         let isBase64 = ((aValue.indexOf("base64") + 7) == start);
         let payload = aValue.substring(start);
         return new Blob([isBase64 ? base64DecToArr(payload) : payload],
                         { type: mimeType });
       } catch(e) {
         dump(e);
       }
     }
     return aValue
   },
   // Makes sure any property that is a data: uri gets converted to a Blob.
   prepareValue: function(aObject) {
     let kind = ObjectWrapper.getObjectKind(aObject);
     if (kind == "array") {
       let res = [];
       aObject.forEach(function(aObj) {
         res.push(this.prepareValue(aObj));
       }, this);
       return res;
     } else if (kind == "file" || kind == "blob" || kind == "date") {
       return aObject;
     } else if (kind == "primitive") {
       return this.convertDataURIToBlob(aObject);
     }
     // Fall-through, we now have a dictionary object.
     for (let prop in aObject) {
       aObject[prop] = this.prepareValue(aObject[prop]);
     }
     return aObject;
   },
   init: function init() {
     this.initDBHelper(SETTINGSDB_NAME, SETTINGSDB_VERSION,
                       [SETTINGSSTORE_NAME]);
   }
 }

The Tor Browser / annotate

dom/settings/SettingsDB.jsm@97036ab72558 (annotated)

dom/settings/SettingsDB.jsm