checkpoints.js

/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 80085):
 * <cperivol@csail.mit.edu> wrote this file. As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return
 *
 * Chris Perivolaropoulos.
 * ----------------------------------------------------------------------------
 */


var assert = require('assert');

function CheckpointManager(timeout) {
  this.checkpoints = {};
  this.timeout = null;
  this.hooks = {};
  this.closed = false;

  if (timeout !== null){
    this.timeout = setTimeout(this.timeoutFail.bind(this), timeout || 1500);
  }
}

CheckpointManager.prototype = {
  timeoutFail: function () {
    throw Error("TIMEOUT: Checkpoints accessed:\n" +
                JSON.stringify(this.checkpoints, null, 2));
  },

  setCheckpoint: function (index, name) {
    var cp = this.checkpoints[index] || {},
        passes = (cp.passes || 0) + 1;

    if (name && cp.name) {
      assert.equal(name, cp.name, "Both checkpoints '" + name +
                   "' and '" + cp.name + "' have index " + index);
    }

    if (index > 1) {
      assert(this.checkpoints[index - 1], "You got to checkpoint " +
             index + "skipping " + index - 1);
    }

    this.checkpoints[index] = {passes: passes, name: name || index,
                               index: index};
    this.triggerHook(index);
  },

  triggerHook: function (id) {
    var checkpoint = this.getCheckpoint(id),
        hook = this.hooks[checkpoint.name];

    if (hook && hook.passes == checkpoint.passes) {
      hook.callback();
      return;
    }
  },

  getCheckpoint: function (idOrName) {
    var self = this;
    return this.checkpoints[idOrName] ||
      Object.getOwnPropertyNames(this.checkpoints)
      .map(function (k) {return self.checkpoints[k];})
      .filter(function (cp) {return cp.name == idOrName;})
      .pop();
  },

  close: function (max, passesDict) {
    var passIds = {}, self = this;
    assert(!this.closed);
    this.closed = true;
    Object.getOwnPropertyNames(passesDict || {}).forEach(function (key) {
      var cp = self.getCheckpoint(key);
      if (cp) passIds[cp.index] = passesDict[key];
    });

    // Check that the incrementing ids were all passed.
    for (var i = 0; i < (max || 0); i++) {
      var expected = passIds[i] || 1;
      assert(this.checkpoints[i], "Skipped checkpoint: " + i +
             JSON.stringify(this.checkpoints));
    }

    // Check that any extra assertions form the passes dict are satisfied.
    Object.getOwnPropertyNames(passesDict || {}).forEach(function (ckp) {
      var cp = self.getCheckpoint(ckp) || {passes: 0, name: ckp};
      assert.equal(cp.passes, passesDict[ckp],
                   "Checkpoint " + ckp + " accessed times: " +
                   cp.passes + " != " + passesDict[ckp]);
    });

    clearTimeout(this.timeout);
  },

  onCheckpoint: function (checkpoint, passes, cb) {
    if (this.checkpoints[checkpoint])
      throw Error("Registered checkpoint hook after checkpoints were reached.");

    this.hooks[checkpoint] = {passes: passes || 1, callback: cb};
  }
};

module.exports = CheckpointManager;

index.js