file-state-monitor/dist/states/SmartState.js

Completely customizable file monitoring using states

"use strict";

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

var _crypto = _interopRequireDefault(require("crypto"));

var _fs = _interopRequireDefault(require("fs"));

var _BaseFileState = _interopRequireDefault(require("./BaseFileState"));

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

/**
 * State that uses a smart detection consting of checks for last modified,
 * file size and SHA-1 hash to detect file changes
 */
class SmartState extends _BaseFileState.default {
  /**
   * Constructs a new combined state
   *
   * @param {Object} fileInfo Object containing existing state data
   */
  constructor(fileInfo) {
    super(fileInfo);

    if (Object.keys(fileInfo).length === 1) {
      let stat = _fs.default.statSync(this.path);

      this._lastModified = stat.mtime.getTime();
      this._size = stat.size;
      this._sha1 = null;
    }
  }
  /**
   * Gets the last modification date of the file
   *
   * @return {number} Last modified date in miliseconds
   */


  get lastModified() {
    return this._lastModified;
  }
  /**
   * Gets the file size of the file
   *
   * @return {number} File size in bytes
   */


  get size() {
    return this._size;
  }
  /**
   * Gets the SHA-1 hash of the file's content
   *
   * @return {string} SHA-1 content hash
   */


  get sha1() {
    if (this._sha1 === null) {
      this._sha1 = this.computeSha1();
    }

    return this._sha1;
  }
  /**
   * Computes the sha1 hash of the files content
   *
   * @return {string} Computed sha1 hash
   */


  computeSha1() {
    let hash = _crypto.default.createHash('sha1');

    hash.update(_fs.default.readFileSync(this.path));
    return hash.digest('hex');
  }
  /**
   * Checks if this file state is different than another given file state
   *
   * We do the checks in order of fastest to slowest. First check the
   * modification times, then for different file size and last one is SHA-1
   * content hash.
   *
   * @param {FileState} otherState File state to check against
   * @return {boolean} True if the two file states are different, false otherwise
   */


  isDifferentThan(otherState) {
    if (this.path !== otherState.path) {
      throw new Error(`Can only compare files with the same path, but tried to compare ${this._path} with ${otherState.path}`);
    }

    if (this.lastModified === otherState.lastModified) {
      return false;
    }

    return this.size !== otherState.size || this.sha1 !== otherState.sha1;
  }
  /**
   * @inheritdoc
   */


  toJson() {
    return {
      path: this.path,
      lastModified: this.lastModified,
      size: this.size,
      sha1: this.sha1
    };
  }

}

exports.default = SmartState;