playback.js

Handles the magic /playback command that plays recordings.

• ¶

  /* 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/. */
  
  define(["jquery", "util", "session", "storage", "require"], function ($, util, session, storage, require) {
    var playback = util.Module("playback");
    var assert = util.assert;
  
    var ALWAYS_REPLAY = {
      "cursor-update": true,
      "scroll-update": true
    };
  
    playback.getLogs = function (url) {
      if (url.search(/^local:/) === 0) {
        return $.Deferred(function (def) {
          storage.get("recording." + url.substr("local:".length)).then(function (logs) {
            if (! logs) {
              def.resolve(null);
              return;
            }
            logs = parseLogs(logs);
            def.resolve(logs);
          }, function (error) {
            def.reject(error);
          });
        });
      }
      return $.Deferred(function (def) {
        $.ajax({
          url: url,
          dataType: "text"
        }).then(
          function (logs) {
            logs = parseLogs(logs);
            def.resolve(logs);
          },
          function (error) {
            def.reject(error);
          });
      });
    };
  
    function parseLogs(logs) {
      logs = logs.replace(/\r\n/g, '\n');
      logs = logs.split(/\n/g);
      var result = [];
      for (var i=0; i<logs.length; i++) {
        var line = logs[i];
        line = line.replace(/^\s+/, "").replace(/\s+$/, "");
        if (line.search(/\/\*/) === 0) {
          var last = line.search(/\*\//);
          if (last == -1) {
            console.warn("bad line:", line);
            continue;
          }
          line = line.substr(last+2);
        }
        line = line.replace(/^\s+/, "");
        if (! line) {
          continue;
        }
        line = JSON.parse(line);
        result.push(line);
      }
      return Logs(result);
    }
  
    var Logs = util.Class({
      constructor: function (logs, fromStorage) {
        this.logs = logs;
        this.fromStorage = fromStorage;
        this.pos = 0;
      },
  
      play: function () {
        this.start = Date.now();
        if (this.pos >= this.logs.length) {
          this.unload();
          return;
        }
        if (this.pos !== 0) {

• ¶

  First we need to play the hello

          var toReplay = [];
          var foundHello = false;
          for (var i=this.pos-1; i>=0; i--) {
            var item = this.logs[i];
            if (ALWAYS_REPLAY[item.type]) {
              toReplay.push(item);
            }
            if (item.type == "hello" || item.type == "hello-back") {
              this.playItem(item);
              foundHello = true;
              break;
            }
          }
          if (! foundHello) {
            console.warn("No hello message found before position", this.pos);
          }
          toReplay.reverse();
          for (i=0; i<toReplay.length; i++) {
            this.playItem(toReplay[i]);
          }
        }
        this.playOne();
      },
  
      cancel: function () {
        if (this.playTimer) {
          clearTimeout(this.playTimer);
          this.playTimer = null;
        }
        this.start = null;
        this.pos = 0;
        this.unload();
      },
  
      pause: function () {
        if (this.playTimer) {
          clearTimeout(this.playTimer);
          this.playTimer = null;
        }
      },
  
      playOne: function () {
        this.playTimer = null;
        if (this.pos >= this.logs.length) {
          this.unload();
          return;
        }
        var item = this.logs[this.pos];
        this.playItem(item);
        this.pos++;
        if (this.pos >= this.logs.length) {
          this.unload();
          return;
        }
        var next = this.logs[this.pos];
        var pause = next.date - item.date;
        this.playTimer = setTimeout(this.playOne.bind(this), pause);
        if (this.fromStorage) {
          this.savePos();
        }
      },
  
      playItem: function (item) {
        if (item.type == "hello") {

• ¶

  We may need to pause here

          if (item.url != (location.href+"").replace(/\#.*/, "")) {
            this.pause();
          }
        }
        try {
          session._getChannel().onmessage(item);
        } catch (e) {
          console.warn("Could not play back message:", item, "error:", e);
        }
      },
  
      save: function () {
        this.fromStorage = true;
        storage.set("playback.logs", this.logs);
        this.savePos();
      },
  
      savePos: function () {
        storage.set("playback.pos", this.pos);
      },
  
      unload: function () {
        if (this.fromStorage) {
          storage.set("playback.logs", undefined);
          storage.set("playback.pos", undefined);
        }

• ¶

  FIXME: should do a bye message here

      }
  
    });
  
    playback.getRunningLogs = function () {
      return storage.get("playback.logs").then(function (value) {
        if (! value) {
          return null;
        }
        var logs = Logs(value, true);
        return storage.get("playback.pos").then(function (pos) {
          pos = pos || 0;
          logs.pos = pos;
          return logs;
        });
      });
    };
  
    return playback;
  });