prepack/lib/statistics.js

Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.PerformanceTracker = exports.RealmStatistics = void 0;

var _invariant = _interopRequireDefault(require("./invariant.js"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Copyright (c) 2017-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */
class RealmStatistics {
  constructor(getTime, getMemory) {
    this.simplifications = 0;
    this.simplificationAttempts = 0;
    this.evaluatedNodes = 0;
    this.parsing = new PerformanceTracker(getTime, getMemory);
    this.fixupSourceLocations = new PerformanceTracker(getTime, getMemory);
    this.fixupFilenames = new PerformanceTracker(getTime, getMemory);
    this.evaluation = new PerformanceTracker(getTime, getMemory);
  }

  // legacy projection
  getRealmStatistics() {
    return {
      simplifications: this.simplifications,
      simplificationAttempts: this.simplificationAttempts,
      evaluatedNodes: this.evaluatedNodes
    };
  }

  projectPerformanceTrackers(suffix, projection) {
    let res = {};

    for (let key of Object.keys(this)) {
      let value = this[key];
      if (value instanceof PerformanceTracker) res[key + suffix] = projection(value);
    }

    return res;
  }

  log() {
    console.log(`=== realm statistics`);
    console.log(`${this.evaluatedNodes} AST nodes evaluated.`);
    console.log(`${this.simplifications} abstract values simplified after ${this.simplificationAttempts} attempts.`);
  }

  logPerformanceTrackers(format) {
    console.log(`${format(this.parsing)} parsing, ${format(this.fixupSourceLocations)} fixing source locations, ${format(this.fixupFilenames)} fixing filenames, ${format(this.evaluation)} evaluating global code`);
  }

}

exports.RealmStatistics = RealmStatistics;

class PerformanceTracker {
  constructor(getTime, getMemory) {
    this.time = this.memory = 0;
    this._getTime = getTime;
    this._getMemory = getMemory;
    this._running = false;
  }

  start() {
    (0, _invariant.default)(this._running === false);
    if (this._getTime !== undefined) this.time = this._getTime() - this.time;
    if (this._getMemory !== undefined) this.memory = this._getMemory() - this.memory;
    this._running = true;
  }

  stop() {
    (0, _invariant.default)(this._running === true);
    if (this._getTime !== undefined) this.time = this._getTime() - this.time;
    if (this._getMemory !== undefined) this.memory = this._getMemory() - this.memory;
    this._running = false;
  }

  measure(action) {
    this.start();

    try {
      return action();
    } finally {
      this.stop();
    }
  }

}

exports.PerformanceTracker = PerformanceTracker;
//# sourceMappingURL=statistics.js.map