gecko/services/sync/modules/base_records/collection.js

/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Weave.
 *
 * The Initial Developer of the Original Code is Mozilla.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Dan Mills <thunder@mozilla.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

const EXPORTED_SYMBOLS = ['Collection'];

const Cc = Components.classes;
const Ci = Components.interfaces;
const Cr = Components.results;
const Cu = Components.utils;

Cu.import("resource://weave/log4moz.js");
Cu.import("resource://weave/constants.js");
Cu.import("resource://weave/util.js");
Cu.import("resource://weave/resource.js");
Cu.import("resource://weave/base_records/wbo.js");
Cu.import("resource://weave/base_records/crypto.js");
Cu.import("resource://weave/base_records/keys.js");

function Collection(uri, recordObj) {
  this._Coll_init(uri);
  this._recordObj = recordObj;
}
Collection.prototype = {
  __proto__: Resource.prototype,
  _logName: "Collection",

  _Coll_init: function Coll_init(uri) {
    this._init(uri);
    this.pushFilter(new JsonFilter());
    this._full = true;
    this._older = 0;
    this._newer = 0;
    this._data = [];
  },

  _rebuildURL: function Coll__rebuildURL() {
    // XXX should consider what happens if it's not a URL...
    this.uri.QueryInterface(Ci.nsIURL);

    let args = [];
    if (this.older)
      args.push('older=' + this.older);
    else if (this.newer) {
      args.push('newer=' + this.newer);
      args.push('modified=' + this.newer); // tmp hack for older servers
    }
    if (this.full)
      args.push('full=1');
    if (this.sort)
      args.push('sort=' + this.sort);

    this.uri.query = (args.length > 0)? '?' + args.join('&') : '';
  },

  // get full items
  get full() { return this._full; },
  set full(value) {
    this._full = value;
    this._rebuildURL();
  },

  // get only items modified before some date
  get older() { return this._older; },
  set older(value) {
    this._older = value;
    this._rebuildURL();
  },

  // get only items modified since some date
  get newer() { return this._newer; },
  set newer(value) {
    this._newer = value;
    this._rebuildURL();
  },

  // get items sorted by some criteria. valid values:
  // oldest (oldest first)
  // newest (newest first)
  // index
  get sort() { return this._sort; },
  set sort(value) {
    this._sort = value;
    this._rebuildURL();
  },

  pushData: function Coll_pushData(data) {
    this._data.push(data);
  },

  clearRecords: function Coll_clearRecords() {
    this._data = [];
  },

  set recordHandler(onRecord) {
    // Save this because onProgress is called with this as the ChannelListener
    let coll = this;

    this._onProgress = function() {
      // Save some work by quitting early when there's no records
      if (this._data == "[]")
        return;

      do {
        // Strip off the the starting "[" or separating "," or trailing "]" if
        // it wasn't stripped off from a previous progress update
        let start = this._data[0];
        if (start == "[" || start == "," || start == "]")
          this._data = this._data.slice(1);

        // Track various states of # open braces and ignore for strings
        let json = "";
        let braces = 1;
        let ignore = false;
        let escaped = false;
        let length = this._data.length;

        // Skip the first character, the "{", and try to find a json record
        for (let i = 1; i < length; i++) {
          let char = this._data[i];

          // Opening a string makes us ignore all characters except close "
          if (char == '"') {
            if (!ignore)
              ignore = true;
            // It's a real close " if it's not escaped
            else if (!escaped)
              ignore = false;
          }

          // Track if an end quote might be escaped when processing strings
          if (ignore) {
            escaped = char == "\\" ? !escaped : false;

            // Don't bother checking other characters when ignoring
            continue;
          }

          // Increase the brace count on open {
          if (char == "{")
            braces++;
          // Decrement brace count on close }
          else if (char == "}" && --braces == 0) {
            // Split the json record from the rest of the data
            json = this._data.slice(0, i + 1);
            this._data = this._data.slice(i + 1);

            // Stop processing for now that we found one record
            break;
          }
        }

        // No valid record json found?
        if (json.length == 0)
          break;

        // Deserialize a record from json and give it to the callback
        let record = new coll._recordObj();
        record.deserialize(json);
        record.baseURI = coll.uri;
        record.id = record.data.id;
        onRecord(record);

      // Keep processing the data until we can't find a json record
      } while (true);

      // Aggressively clean up the objects we created above so that the next set
      // of records have enough memory to decrypt, reconcile, apply, etc.
      Cu.forceGC();
    };
  }
};