chrome/browser/resources/cryptotoken/watchdog.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview Provides a watchdog around a collection of callback functions.
   7  */
   8 'use strict';
   9
  10 /**
  11  * Creates a watchdog around a collection of callback functions,
  12  * ensuring at least one of them is called before the timeout expires.
  13  * If a timeout function is provided, calls the timeout function upon timeout
  14  * expiration if none of the callback functions has been called.
  15  * @param {number} timeoutValueSeconds Timeout value, in seconds.
  16  * @param {function()=} opt_timeoutCb Callback function to call on timeout.
  17  * @constructor
  18  * @implements {Closeable}
  19  */
  20 function WatchdogRequestHandler(timeoutValueSeconds, opt_timeoutCb) {
  21   /** @private {number} */
  22   this.timeoutValueSeconds_ = timeoutValueSeconds;
  23   /** @private {function()|undefined} */
  24   this.timeoutCb_ = opt_timeoutCb;
  25   /** @private {boolean} */
  26   this.calledBack_ = false;
  27   /** @private {Countdown} */
  28   this.timer_ = FACTORY_REGISTRY.getCountdownFactory().createTimer(
  29       this.timeoutValueSeconds_ * 1000, this.timeout_.bind(this));
  30   /** @private {Closeable|undefined} */
  31   this.closeable_ = undefined;
  32   /** @private {boolean} */
  33   this.closed_ = false;
  34 }
  35
  36 /**
  37  * Wraps a callback function, such that the fact that the callback function
  38  * was or was not called gets tracked by this watchdog object.
  39  * @param {function(...?)} cb The callback function to wrap.
  40  * @return {function(...?)} A wrapped callback function.
  41  */
  42 WatchdogRequestHandler.prototype.wrapCallback = function(cb) {
  43   return this.wrappedCallback_.bind(this, cb);
  44 };
  45
  46 /** Closes this watchdog. */
  47 WatchdogRequestHandler.prototype.close = function() {
  48   this.closed_ = true;
  49   this.timer_.clearTimeout();
  50   if (this.closeable_) {
  51     this.closeable_.close();
  52     this.closeable_ = undefined;
  53   }
  54 };
  55
  56 /**
  57  * Sets this watchdog's closeable.
  58  * @param {!Closeable} closeable The closeable.
  59  */
  60 WatchdogRequestHandler.prototype.setCloseable = function(closeable) {
  61   this.closeable_ = closeable;
  62 };
  63
  64 /**
  65  * Called back when the watchdog expires.
  66  * @private
  67  */
  68 WatchdogRequestHandler.prototype.timeout_ = function() {
  69   if (!this.calledBack_ && !this.closed_) {
  70     var logMsg = 'Not called back within ' + this.timeoutValueSeconds_ +
  71         ' second timeout';
  72     if (this.timeoutCb_) {
  73       logMsg += ', calling default callback';
  74       console.warn(UTIL_fmt(logMsg));
  75       this.timeoutCb_();
  76     } else {
  77       console.warn(UTIL_fmt(logMsg));
  78     }
  79   }
  80 };
  81
  82 /**
  83  * Wrapped callback function.
  84  * @param {function(...?)} cb The callback function to call.
  85  * @param {...?} var_args The callback function's arguments.
  86  * @private
  87  */
  88 WatchdogRequestHandler.prototype.wrappedCallback_ = function(cb, var_args) {
  89   if (!this.closed_) {
  90     this.calledBack_ = true;
  91     this.timer_.clearTimeout();
  92     var originalArgs = Array.prototype.slice.call(arguments, 1);
  93     cb.apply(null, originalArgs);
  94   }
  95 };