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   1  // This file is part of Moodle - http://moodle.org/
   2  //
   3  // Moodle is free software: you can redistribute it and/or modify
   4  // it under the terms of the GNU General Public License as published by
   5  // the Free Software Foundation, either version 3 of the License, or
   6  // (at your option) any later version.
   7  //
   8  // Moodle is distributed in the hope that it will be useful,
   9  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  // GNU General Public License for more details.
  12  //
  13  // You should have received a copy of the GNU General Public License
  14  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  15  /* jshint node: true, browser: false */
  16  /* eslint-env node */
  17  
  18  /**
  19   * @copyright  2014 Andrew Nicols
  20   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  21   */
  22  
  23  /* eslint-env node */
  24  
  25  /**
  26   * Calculate the cwd, taking into consideration the `root` option (for Windows).
  27   *
  28   * @param {Object} grunt
  29   * @returns {String} The current directory as best we can determine
  30   */
  31  const getCwd = grunt => {
  32      const fs = require('fs');
  33      const path = require('path');
  34  
  35      let cwd = fs.realpathSync(process.env.PWD || process.cwd());
  36  
  37      // Windows users can't run grunt in a subdirectory, so allow them to set
  38      // the root by passing --root=path/to/dir.
  39      if (grunt.option('root')) {
  40          const root = grunt.option('root');
  41          if (grunt.file.exists(__dirname, root)) {
  42              cwd = fs.realpathSync(path.join(__dirname, root));
  43              grunt.log.ok('Setting root to ' + cwd);
  44          } else {
  45              grunt.fail.fatal('Setting root to ' + root + ' failed - path does not exist');
  46          }
  47      }
  48  
  49      return cwd;
  50  };
  51  
  52  /**
  53   * Register any stylelint tasks.
  54   *
  55   * @param {Object} grunt
  56   * @param {Array} files
  57   * @param {String} fullRunDir
  58   */
  59  const registerStyleLintTasks = (grunt, files, fullRunDir) => {
  60      const getCssConfigForFiles = files => {
  61          return {
  62              stylelint: {
  63                  css: {
  64                      // Use a fully-qualified path.
  65                      src: files,
  66                      options: {
  67                          configOverrides: {
  68                              rules: {
  69                                  // These rules have to be disabled in .stylelintrc for scss compat.
  70                                  "at-rule-no-unknown": true,
  71                              }
  72                          }
  73                      }
  74                  },
  75              },
  76          };
  77      };
  78  
  79      const getScssConfigForFiles = files => {
  80          return {
  81              stylelint: {
  82                  scss: {
  83                      options: {syntax: 'scss'},
  84                      src: files,
  85                  },
  86              },
  87          };
  88      };
  89  
  90      let hasCss = true;
  91      let hasScss = true;
  92  
  93      if (files) {
  94          // Specific files were passed. Just set them up.
  95          grunt.config.merge(getCssConfigForFiles(files));
  96          grunt.config.merge(getScssConfigForFiles(files));
  97      } else {
  98          // The stylelint system does not handle the case where there was no file to lint.
  99          // Check whether there are any files to lint in the current directory.
 100          const glob = require('glob');
 101  
 102          const scssSrc = [];
 103          glob.sync(`$fullRunDir}/**/*.scss`).forEach(path => scssSrc.push(path));
 104  
 105          if (scssSrc.length) {
 106              grunt.config.merge(getScssConfigForFiles(scssSrc));
 107          } else {
 108              hasScss = false;
 109          }
 110  
 111          const cssSrc = [];
 112          glob.sync(`$fullRunDir}/**/*.css`).forEach(path => cssSrc.push(path));
 113  
 114          if (cssSrc.length) {
 115              grunt.config.merge(getCssConfigForFiles(cssSrc));
 116          } else {
 117              hasCss = false;
 118          }
 119      }
 120  
 121      const scssTasks = ['sass'];
 122      if (hasScss) {
 123          scssTasks.unshift('stylelint:scss');
 124      }
 125      scssTasks.unshift('ignorefiles');
 126      grunt.registerTask('scss', scssTasks);
 127  
 128      const cssTasks = ['ignorefiles'];
 129      if (hasCss) {
 130          cssTasks.push('stylelint:css');
 131      }
 132      grunt.registerTask('rawcss', cssTasks);
 133  
 134      grunt.registerTask('css', ['scss', 'rawcss']);
 135  };
 136  
 137  /**
 138   * Grunt configuration.
 139   *
 140   * @param {Object} grunt
 141   */
 142  module.exports = function(grunt) {
 143      const path = require('path');
 144      const tasks = {};
 145      const async = require('async');
 146      const DOMParser = require('xmldom').DOMParser;
 147      const xpath = require('xpath');
 148      const semver = require('semver');
 149      const watchman = require('fb-watchman');
 150      const watchmanClient = new watchman.Client();
 151      const fs = require('fs');
 152      const ComponentList = require(path.resolve('GruntfileComponents.js'));
 153      const sass = require('node-sass');
 154  
 155      // Verify the node version is new enough.
 156      var expected = semver.validRange(grunt.file.readJSON('package.json').engines.node);
 157      var actual = semver.valid(process.version);
 158      if (!semver.satisfies(actual, expected)) {
 159          grunt.fail.fatal('Node version not satisfied. Require ' + expected + ', version installed: ' + actual);
 160      }
 161  
 162      // Detect directories:
 163      // * gruntFilePath          The real path on disk to this Gruntfile.js
 164      // * cwd                    The current working directory, which can be overridden by the `root` option
 165      // * relativeCwd            The cwd, relative to the Gruntfile.js
 166      // * componentDirectory     The root directory of the component if the cwd is in a valid component
 167      // * inComponent            Whether the cwd is in a valid component
 168      // * runDir                 The componentDirectory or cwd if not in a component, relative to Gruntfile.js
 169      // * fullRunDir             The full path to the runDir
 170      const gruntFilePath = fs.realpathSync(process.cwd());
 171      const cwd = getCwd(grunt);
 172      const relativeCwd = path.relative(gruntFilePath, cwd);
 173      const componentDirectory = ComponentList.getOwningComponentDirectory(relativeCwd);
 174      const inComponent = !!componentDirectory;
 175      const runDir = inComponent ? componentDirectory : relativeCwd;
 176      const fullRunDir = fs.realpathSync(gruntFilePath + path.sep + runDir);
 177      grunt.log.debug('============================================================================');
 178      grunt.log.debug(`= Node version:        $process.versions.node}`);
 179      grunt.log.debug(`= grunt version:       $grunt.package.version}`);
 180      grunt.log.debug(`= process.cwd:         '` + process.cwd() + `'`);
 181      grunt.log.debug(`= process.env.PWD:     '$process.env.PWD}'`);
 182      grunt.log.debug(`= path.sep             '$path.sep}'`);
 183      grunt.log.debug('============================================================================');
 184      grunt.log.debug(`= gruntFilePath:       '$gruntFilePath}'`);
 185      grunt.log.debug(`= relativeCwd:         '$relativeCwd}'`);
 186      grunt.log.debug(`= componentDirectory:  '$componentDirectory}'`);
 187      grunt.log.debug(`= inComponent:         '$inComponent}'`);
 188      grunt.log.debug(`= runDir:              '$runDir}'`);
 189      grunt.log.debug(`= fullRunDir:          '$fullRunDir}'`);
 190      grunt.log.debug('============================================================================');
 191  
 192      if (inComponent) {
 193          grunt.log.ok(`Running tasks for component directory $componentDirectory}`);
 194      }
 195  
 196      let files = null;
 197      if (grunt.option('files')) {
 198          // Accept a comma separated list of files to process.
 199          files = grunt.option('files').split(',');
 200      }
 201  
 202      // If the cwd is the amd directory in the current component then it will be empty.
 203      // If the cwd is a child of the component's AMD directory, the relative directory will not start with ..
 204      const inAMD = !path.relative(`$componentDirectory}/amd`, cwd).startsWith('..');
 205  
 206      // Globbing pattern for matching all AMD JS source files.
 207      let amdSrc = [];
 208      if (inComponent) {
 209          amdSrc.push(componentDirectory + "/amd/src/*.js");
 210          amdSrc.push(componentDirectory + "/amd/src/**/*.js");
 211      } else {
 212          amdSrc = ComponentList.getAmdSrcGlobList();
 213      }
 214  
 215      let yuiSrc = [];
 216      if (inComponent) {
 217          yuiSrc.push(componentDirectory + "/yui/src/**/*.js");
 218      } else {
 219          yuiSrc = ComponentList.getYuiSrcGlobList(gruntFilePath + '/');
 220      }
 221  
 222      /**
 223       * Function to generate the destination for the uglify task
 224       * (e.g. build/file.min.js). This function will be passed to
 225       * the rename property of files array when building dynamically:
 226       * http://gruntjs.com/configuring-tasks#building-the-files-object-dynamically
 227       *
 228       * @param {String} destPath the current destination
 229       * @param {String} srcPath the  matched src path
 230       * @return {String} The rewritten destination path.
 231       */
 232      var babelRename = function(destPath, srcPath) {
 233          destPath = srcPath.replace('src', 'build');
 234          destPath = destPath.replace('.js', '.min.js');
 235          return destPath;
 236      };
 237  
 238      /**
 239       * Find thirdpartylibs.xml and generate an array of paths contained within
 240       * them (used to generate ignore files and so on).
 241       *
 242       * @return {array} The list of thirdparty paths.
 243       */
 244      var getThirdPartyPathsFromXML = function() {
 245          const thirdpartyfiles = ComponentList.getThirdPartyLibsList(gruntFilePath + '/');
 246          const libs = ['node_modules/', 'vendor/'];
 247  
 248          thirdpartyfiles.forEach(function(file) {
 249              const dirname = path.dirname(file);
 250  
 251              const doc = new DOMParser().parseFromString(grunt.file.read(file));
 252              const nodes = xpath.select("/libraries/library/location/text()", doc);
 253  
 254              nodes.forEach(function(node) {
 255                  let lib = path.posix.join(dirname, node.toString());
 256                  if (grunt.file.isDir(lib)) {
 257                      // Ensure trailing slash on dirs.
 258                      lib = lib.replace(/\/?$/, '/');
 259                  }
 260  
 261                  // Look for duplicate paths before adding to array.
 262                  if (libs.indexOf(lib) === -1) {
 263                      libs.push(lib);
 264                  }
 265              });
 266          });
 267  
 268          return libs;
 269      };
 270  
 271      /**
 272       * Get the list of feature files to pass to the gherkin linter.
 273       *
 274       * @returns {Array}
 275       */
 276      const getGherkinLintTargets = () => {
 277          if (files) {
 278              // Specific files were requested. Only check these.
 279              return files;
 280          }
 281  
 282          if (inComponent) {
 283              return [`$runDir}/tests/behat/*.feature`];
 284          }
 285  
 286          return ['**/tests/behat/*.feature'];
 287      };
 288  
 289      const babelTransform = require('@babel/core').transform;
 290      const babel = (options = {}) => {
 291          return {
 292              name: 'babel',
 293  
 294              transform: (code, id) => {
 295                  grunt.log.debug(`Transforming ${id}`);
 296                  options.filename = id;
 297                  const transformed = babelTransform(code, options);
 298  
 299                  return {
 300                      code: transformed.code,
 301                      map: transformed.map
 302                  };
 303              }
 304          };
 305      };
 306  
 307      // Note: We have to use a rate limit plugin here because rollup runs all tasks asynchronously and in parallel.
 308      // When we kick off a full run, if we kick off a rollup of every file this will fork-bomb the machine.
 309      // To work around this we use a concurrent Promise queue based on the number of available processors.
 310      const rateLimit = () => {
 311          const queue = [];
 312          let queueRunner;
 313  
 314          const startQueue = () => {
 315              if (queueRunner) {
 316                  return;
 317              }
 318  
 319              queueRunner = setTimeout(() => {
 320                  const limit = Math.max(1, require('os').cpus().length / 2);
 321                  grunt.log.debug(`Starting rollup with queue size of ${limit}`);
 322                  runQueue(limit);
 323              }, 100);
 324          };
 325  
 326          // The queue runner will run the next `size` items in the queue.
 327          const runQueue = (size = 1) => {
 328              queue.splice(0, size).forEach(resolve => {
 329                  resolve();
 330              });
 331          };
 332  
 333          return {
 334              name: 'ratelimit',
 335  
 336              // The options hook is run in parallel.
 337              // We can return an unresolved Promise which is queued for later resolution.
 338              options: async() => {
 339                  return new Promise(resolve => {
 340                      queue.push(resolve);
 341                      startQueue();
 342                  });
 343              },
 344  
 345              // When an item in the queue completes, start the next item in the queue.
 346              buildEnd: () => {
 347                  runQueue();
 348              },
 349          };
 350      };
 351  
 352      const terser = require('rollup-plugin-terser').terser;
 353  
 354      // Project configuration.
 355      grunt.initConfig({
 356          eslint: {
 357              // Even though warnings dont stop the build we don't display warnings by default because
 358              // at this moment we've got too many core warnings.
 359              // To display warnings call: grunt eslint --show-lint-warnings
 360              // To fail on warnings call: grunt eslint --max-lint-warnings=0
 361              // Also --max-lint-warnings=-1 can be used to display warnings but not fail.
 362              options: {
 363                  quiet: (!grunt.option('show-lint-warnings')) && (typeof grunt.option('max-lint-warnings') === 'undefined'),
 364                  maxWarnings: ((typeof grunt.option('max-lint-warnings') !== 'undefined') ? grunt.option('max-lint-warnings') : -1)
 365              },
 366              amd: {src: files ? files : amdSrc},
 367              // Check YUI module source files.
 368              yui: {src: files ? files : yuiSrc},
 369          },
 370          rollup: {
 371              dist: {
 372                  options: {
 373                      format: 'esm',
 374                      dir: 'output',
 375                      sourcemap: true,
 376                      treeshake: false,
 377                      context: 'window',
 378                      plugins: [
 379                          rateLimit({initialDelay: 0}),
 380                          babel({
 381                              sourceMaps: true,
 382                              comments: false,
 383                              compact: false,
 384                              plugins: [
 385                                  'transform-es2015-modules-amd-lazy',
 386                                  'system-import-transformer',
 387                                  // This plugin modifies the Babel transpiling for "export default"
 388                                  // so that if it's used then only the exported value is returned
 389                                  // by the generated AMD module.
 390                                  //
 391                                  // It also adds the Moodle plugin name to the AMD module definition
 392                                  // so that it can be imported as expected in other modules.
 393                                  path.resolve('babel-plugin-add-module-to-define.js'),
 394                                  '@babel/plugin-syntax-dynamic-import',
 395                                  '@babel/plugin-syntax-import-meta',
 396                                  ['@babel/plugin-proposal-class-properties', {'loose': false}],
 397                                  '@babel/plugin-proposal-json-strings'
 398                              ],
 399                              presets: [
 400                                  ['@babel/preset-env', {
 401                                      targets: {
 402                                          browsers: [
 403                                              ">0.25%",
 404                                              "last 2 versions",
 405                                              "not ie <= 10",
 406                                              "not op_mini all",
 407                                              "not Opera > 0",
 408                                              "not dead"
 409                                          ]
 410                                      },
 411                                      modules: false,
 412                                      useBuiltIns: false
 413                                  }]
 414                              ]
 415                          }),
 416  
 417                          terser({
 418                              // Do not mangle variables.
 419                              // Makes debugging easier.
 420                              mangle: false,
 421                          }),
 422                      ],
 423                  },
 424                  files: [{
 425                      expand: true,
 426                      src: files ? files : amdSrc,
 427                      rename: babelRename
 428                  }],
 429              },
 430          },
 431          jsdoc: {
 432              dist: {
 433                  options: {
 434                      configure: ".grunt/jsdoc/jsdoc.conf.js",
 435                  },
 436              },
 437          },
 438          sass: {
 439              dist: {
 440                  files: {
 441                      "theme/boost/style/moodle.css": "theme/boost/scss/preset/default.scss",
 442                      "theme/classic/style/moodle.css": "theme/classic/scss/classicgrunt.scss"
 443                  }
 444              },
 445              options: {
 446                  implementation: sass,
 447                  includePaths: ["theme/boost/scss/", "theme/classic/scss/"]
 448              }
 449          },
 450          watch: {
 451              options: {
 452                  nospawn: true // We need not to spawn so config can be changed dynamically.
 453              },
 454              amd: {
 455                  files: inComponent
 456                      ? ['amd/src/*.js', 'amd/src/**/*.js']
 457                      : ['**/amd/src/**/*.js'],
 458                  tasks: ['amd']
 459              },
 460              boost: {
 461                  files: [inComponent ? 'scss/**/*.scss' : 'theme/boost/scss/**/*.scss'],
 462                  tasks: ['scss']
 463              },
 464              rawcss: {
 465                  files: [
 466                      '**/*.css',
 467                  ],
 468                  excludes: [
 469                      '**/moodle.css',
 470                      '**/editor.css',
 471                  ],
 472                  tasks: ['rawcss']
 473              },
 474              yui: {
 475                  files: inComponent
 476                      ? ['yui/src/*.json', 'yui/src/**/*.js']
 477                      : ['**/yui/src/**/*.js'],
 478                  tasks: ['yui']
 479              },
 480              gherkinlint: {
 481                  files: [inComponent ? 'tests/behat/*.feature' : '**/tests/behat/*.feature'],
 482                  tasks: ['gherkinlint']
 483              }
 484          },
 485          shifter: {
 486              options: {
 487                  recursive: true,
 488                  // Shifter takes a relative path.
 489                  paths: files ? files : [runDir]
 490              }
 491          },
 492          gherkinlint: {
 493              options: {
 494                  files: getGherkinLintTargets(),
 495              }
 496          },
 497      });
 498  
 499      /**
 500       * Generate ignore files (utilising thirdpartylibs.xml data)
 501       */
 502      tasks.ignorefiles = function() {
 503          // An array of paths to third party directories.
 504          const thirdPartyPaths = getThirdPartyPathsFromXML();
 505          // Generate .eslintignore.
 506          const eslintIgnores = [
 507              '# Generated by "grunt ignorefiles"',
 508              '*/**/yui/src/*/meta/',
 509              '*/**/build/',
 510          ].concat(thirdPartyPaths);
 511          grunt.file.write('.eslintignore', eslintIgnores.join('\n') + '\n');
 512  
 513          // Generate .stylelintignore.
 514          const stylelintIgnores = [
 515              '# Generated by "grunt ignorefiles"',
 516              '**/yui/build/*',
 517              'theme/boost/style/moodle.css',
 518              'theme/classic/style/moodle.css',
 519          ].concat(thirdPartyPaths);
 520          grunt.file.write('.stylelintignore', stylelintIgnores.join('\n') + '\n');
 521      };
 522  
 523      /**
 524       * Shifter task. Is configured with a path to a specific file or a directory,
 525       * in the case of a specific file it will work out the right module to be built.
 526       *
 527       * Note that this task runs the invidiaul shifter jobs async (becase it spawns
 528       * so be careful to to call done().
 529       */
 530      tasks.shifter = function() {
 531          var done = this.async(),
 532              options = grunt.config('shifter.options');
 533  
 534          // Run the shifter processes one at a time to avoid confusing output.
 535          async.eachSeries(options.paths, function(src, filedone) {
 536              var args = [];
 537              args.push(path.normalize(__dirname + '/node_modules/shifter/bin/shifter'));
 538  
 539              // Always ignore the node_modules directory.
 540              args.push('--excludes', 'node_modules');
 541  
 542              // Determine the most appropriate options to run with based upon the current location.
 543              if (grunt.file.isMatch('**/yui/**/*.js', src)) {
 544                  // When passed a JS file, build our containing module (this happen with
 545                  // watch).
 546                  grunt.log.debug('Shifter passed a specific JS file');
 547                  src = path.dirname(path.dirname(src));
 548                  options.recursive = false;
 549              } else if (grunt.file.isMatch('**/yui/src', src)) {
 550                  // When in a src directory --walk all modules.
 551                  grunt.log.debug('In a src directory');
 552                  args.push('--walk');
 553                  options.recursive = false;
 554              } else if (grunt.file.isMatch('**/yui/src/*', src)) {
 555                  // When in module, only build our module.
 556                  grunt.log.debug('In a module directory');
 557                  options.recursive = false;
 558              } else if (grunt.file.isMatch('**/yui/src/*/js', src)) {
 559                  // When in module src, only build our module.
 560                  grunt.log.debug('In a source directory');
 561                  src = path.dirname(src);
 562                  options.recursive = false;
 563              }
 564  
 565              if (grunt.option('watch')) {
 566                  grunt.fail.fatal('The --watch option has been removed, please use `grunt watch` instead');
 567              }
 568  
 569              // Add the stderr option if appropriate
 570              if (grunt.option('verbose')) {
 571                  args.push('--lint-stderr');
 572              }
 573  
 574              if (grunt.option('no-color')) {
 575                  args.push('--color=false');
 576              }
 577  
 578              var execShifter = function() {
 579  
 580                  grunt.log.ok("Running shifter on " + src);
 581                  grunt.util.spawn({
 582                      cmd: "node",
 583                      args: args,
 584                      opts: {cwd: src, stdio: 'inherit', env: process.env}
 585                  }, function(error, result, code) {
 586                      if (code) {
 587                          grunt.fail.fatal('Shifter failed with code: ' + code);
 588                      } else {
 589                          grunt.log.ok('Shifter build complete.');
 590                          filedone();
 591                      }
 592                  });
 593              };
 594  
 595              // Actually run shifter.
 596              if (!options.recursive) {
 597                  execShifter();
 598              } else {
 599                  // Check that there are yui modules otherwise shifter ends with exit code 1.
 600                  if (grunt.file.expand({cwd: src}, '**/yui/src/**/*.js').length > 0) {
 601                      args.push('--recursive');
 602                      execShifter();
 603                  } else {
 604                      grunt.log.ok('No YUI modules to build.');
 605                      filedone();
 606                  }
 607              }
 608          }, done);
 609      };
 610  
 611      tasks.gherkinlint = function() {
 612          const done = this.async();
 613          const options = grunt.config('gherkinlint.options');
 614  
 615          // Grab the gherkin-lint linter and required scaffolding.
 616          const linter = require('gherkin-lint/dist/linter.js');
 617          const featureFinder = require('gherkin-lint/dist/feature-finder.js');
 618          const configParser = require('gherkin-lint/dist/config-parser.js');
 619          const formatter = require('gherkin-lint/dist/formatters/stylish.js');
 620  
 621          // Run the linter.
 622          return linter.lint(
 623              featureFinder.getFeatureFiles(grunt.file.expand(options.files)),
 624              configParser.getConfiguration(configParser.defaultConfigFileName)
 625          )
 626          .then(results => {
 627              // Print the results out uncondtionally.
 628              formatter.printResults(results);
 629  
 630              return results;
 631          })
 632          .then(results => {
 633              // Report on the results.
 634              // The done function takes a bool whereby a falsey statement causes the task to fail.
 635              return results.every(result => result.errors.length === 0);
 636          })
 637          .then(done); // eslint-disable-line promise/no-callback-in-promise
 638      };
 639  
 640      tasks.startup = function() {
 641          // Are we in a YUI directory?
 642          if (path.basename(path.resolve(cwd, '../../')) == 'yui') {
 643              grunt.task.run('yui');
 644          // Are we in an AMD directory?
 645          } else if (inAMD) {
 646              grunt.task.run('amd');
 647          } else {
 648              // Run them all!.
 649              grunt.task.run('css');
 650              grunt.task.run('js');
 651              grunt.task.run('gherkinlint');
 652          }
 653      };
 654  
 655      /**
 656       * This is a wrapper task to handle the grunt watch command. It attempts to use
 657       * Watchman to monitor for file changes, if it's installed, because it's much faster.
 658       *
 659       * If Watchman isn't installed then it falls back to the grunt-contrib-watch file
 660       * watcher for backwards compatibility.
 661       */
 662      tasks.watch = function() {
 663          var watchTaskDone = this.async();
 664          var watchInitialised = false;
 665          var watchTaskQueue = {};
 666          var processingQueue = false;
 667  
 668          // Grab the tasks and files that have been queued up and execute them.
 669          var processWatchTaskQueue = function() {
 670              if (!Object.keys(watchTaskQueue).length || processingQueue) {
 671                  // If there is nothing in the queue or we're already processing then wait.
 672                  return;
 673              }
 674  
 675              processingQueue = true;
 676  
 677              // Grab all tasks currently in the queue.
 678              var queueToProcess = watchTaskQueue;
 679              // Reset the queue.
 680              watchTaskQueue = {};
 681  
 682              async.forEachSeries(
 683                  Object.keys(queueToProcess),
 684                  function(task, next) {
 685                      var files = queueToProcess[task];
 686                      var filesOption = '--files=' + files.join(',');
 687                      grunt.log.ok('Running task ' + task + ' for files ' + filesOption);
 688  
 689                      // Spawn the task in a child process so that it doesn't kill this one
 690                      // if it failed.
 691                      grunt.util.spawn(
 692                          {
 693                              // Spawn with the grunt bin.
 694                              grunt: true,
 695                              // Run from current working dir and inherit stdio from process.
 696                              opts: {
 697                                  cwd: fullRunDir,
 698                                  stdio: 'inherit'
 699                              },
 700                              args: [task, filesOption]
 701                          },
 702                          function(err, res, code) {
 703                              if (code !== 0) {
 704                                  // The grunt task failed.
 705                                  grunt.log.error(err);
 706                              }
 707  
 708                              // Move on to the next task.
 709                              next();
 710                          }
 711                      );
 712                  },
 713                  function() {
 714                      // No longer processing.
 715                      processingQueue = false;
 716                      // Once all of the tasks are done then recurse just in case more tasks
 717                      // were queued while we were processing.
 718                      processWatchTaskQueue();
 719                  }
 720              );
 721          };
 722  
 723          const originalWatchConfig = grunt.config.get(['watch']);
 724          const watchConfig = Object.keys(originalWatchConfig).reduce(function(carry, key) {
 725              if (key == 'options') {
 726                  return carry;
 727              }
 728  
 729              const value = originalWatchConfig[key];
 730  
 731              const taskNames = value.tasks;
 732              const files = value.files;
 733              let excludes = [];
 734              if (value.excludes) {
 735                  excludes = value.excludes;
 736              }
 737  
 738              taskNames.forEach(function(taskName) {
 739                  carry[taskName] = {
 740                      files,
 741                      excludes,
 742                  };
 743              });
 744  
 745              return carry;
 746          }, {});
 747  
 748          watchmanClient.on('error', function(error) {
 749              // We have to add an error handler here and parse the error string because the
 750              // example way from the docs to check if Watchman is installed doesn't actually work!!
 751              // See: https://github.com/facebook/watchman/issues/509
 752              if (error.message.match('Watchman was not found')) {
 753                  // If watchman isn't installed then we should fallback to the other watch task.
 754                  grunt.log.ok('It is recommended that you install Watchman for better performance using the "watch" command.');
 755  
 756                  // Fallback to the old grunt-contrib-watch task.
 757                  grunt.renameTask('watch-grunt', 'watch');
 758                  grunt.task.run(['watch']);
 759                  // This task is finished.
 760                  watchTaskDone(0);
 761              } else {
 762                  grunt.log.error(error);
 763                  // Fatal error.
 764                  watchTaskDone(1);
 765              }
 766          });
 767  
 768          watchmanClient.on('subscription', function(resp) {
 769              if (resp.subscription !== 'grunt-watch') {
 770                  return;
 771              }
 772  
 773              resp.files.forEach(function(file) {
 774                  grunt.log.ok('File changed: ' + file.name);
 775  
 776                  var fullPath = fullRunDir + '/' + file.name;
 777                  Object.keys(watchConfig).forEach(function(task) {
 778  
 779                      const fileGlobs = watchConfig[task].files;
 780                      var match = fileGlobs.some(function(fileGlob) {
 781                          return grunt.file.isMatch(`**/$fileGlob}`, fullPath);
 782                      });
 783  
 784                      if (match) {
 785                          // If we are watching a subdirectory then the file.name will be relative
 786                          // to that directory. However the grunt tasks  expect the file paths to be
 787                          // relative to the Gruntfile.js location so let's normalise them before
 788                          // adding them to the queue.
 789                          var relativePath = fullPath.replace(gruntFilePath + '/', '');
 790                          if (task in watchTaskQueue) {
 791                              if (!watchTaskQueue[task].includes(relativePath)) {
 792                                  watchTaskQueue[task] = watchTaskQueue[task].concat(relativePath);
 793                              }
 794                          } else {
 795                              watchTaskQueue[task] = [relativePath];
 796                          }
 797                      }
 798                  });
 799              });
 800  
 801              processWatchTaskQueue();
 802          });
 803  
 804          process.on('SIGINT', function() {
 805              // Let the user know that they may need to manually stop the Watchman daemon if they
 806              // no longer want it running.
 807              if (watchInitialised) {
 808                  grunt.log.ok('The Watchman daemon may still be running and may need to be stopped manually.');
 809              }
 810  
 811              process.exit();
 812          });
 813  
 814          // Initiate the watch on the current directory.
 815          watchmanClient.command(['watch-project', fullRunDir], function(watchError, watchResponse) {
 816              if (watchError) {
 817                  grunt.log.error('Error initiating watch:', watchError);
 818                  watchTaskDone(1);
 819                  return;
 820              }
 821  
 822              if ('warning' in watchResponse) {
 823                  grunt.log.error('warning: ', watchResponse.warning);
 824              }
 825  
 826              var watch = watchResponse.watch;
 827              var relativePath = watchResponse.relative_path;
 828              watchInitialised = true;
 829  
 830              watchmanClient.command(['clock', watch], function(clockError, clockResponse) {
 831                  if (clockError) {
 832                      grunt.log.error('Failed to query clock:', clockError);
 833                      watchTaskDone(1);
 834                      return;
 835                  }
 836  
 837                  // Generate the expression query used by watchman.
 838                  // Documentation is limited, but see https://facebook.github.io/watchman/docs/expr/allof.html for examples.
 839                  // We generate an expression to match any value in the files list of all of our tasks, but excluding
 840                  // all value in the  excludes list of that task.
 841                  //
 842                  // [anyof, [
 843                  //      [allof, [
 844                  //          [anyof, [
 845                  //              ['match', validPath, 'wholename'],
 846                  //              ['match', validPath, 'wholename'],
 847                  //          ],
 848                  //          [not,
 849                  //              [anyof, [
 850                  //                  ['match', invalidPath, 'wholename'],
 851                  //                  ['match', invalidPath, 'wholename'],
 852                  //              ],
 853                  //          ],
 854                  //      ],
 855                  var matchWholeName = fileGlob => ['match', fileGlob, 'wholename'];
 856                  var matches = Object.keys(watchConfig).map(function(task) {
 857                      const matchAll = [];
 858                      matchAll.push(['anyof'].concat(watchConfig[task].files.map(matchWholeName)));
 859  
 860                      if (watchConfig[task].excludes.length) {
 861                          matchAll.push(['not', ['anyof'].concat(watchConfig[task].excludes.map(matchWholeName))]);
 862                      }
 863  
 864                      return ['allof'].concat(matchAll);
 865                  });
 866  
 867                  matches = ['anyof'].concat(matches);
 868  
 869                  var sub = {
 870                      expression: matches,
 871                      // Which fields we're interested in.
 872                      fields: ["name", "size", "type"],
 873                      // Add our time constraint.
 874                      since: clockResponse.clock
 875                  };
 876  
 877                  if (relativePath) {
 878                      /* eslint-disable camelcase */
 879                      sub.relative_root = relativePath;
 880                  }
 881  
 882                  watchmanClient.command(['subscribe', watch, 'grunt-watch', sub], function(subscribeError) {
 883                      if (subscribeError) {
 884                          // Probably an error in the subscription criteria.
 885                          grunt.log.error('failed to subscribe: ', subscribeError);
 886                          watchTaskDone(1);
 887                          return;
 888                      }
 889  
 890                      grunt.log.ok('Listening for changes to files in ' + fullRunDir);
 891                  });
 892              });
 893          });
 894      };
 895  
 896      // On watch, we dynamically modify config to build only affected files. This
 897      // method is slightly complicated to deal with multiple changed files at once (copied
 898      // from the grunt-contrib-watch readme).
 899      var changedFiles = Object.create(null);
 900      var onChange = grunt.util._.debounce(function() {
 901          var files = Object.keys(changedFiles);
 902          grunt.config('eslint.amd.src', files);
 903          grunt.config('eslint.yui.src', files);
 904          grunt.config('shifter.options.paths', files);
 905          grunt.config('gherkinlint.options.files', files);
 906          grunt.config('babel.dist.files', [{expand: true, src: files, rename: babelRename}]);
 907          changedFiles = Object.create(null);
 908      }, 200);
 909  
 910      grunt.event.on('watch', function(action, filepath) {
 911          changedFiles[filepath] = action;
 912          onChange();
 913      });
 914  
 915      // Register NPM tasks.
 916      grunt.loadNpmTasks('grunt-contrib-uglify');
 917      grunt.loadNpmTasks('grunt-contrib-watch');
 918      grunt.loadNpmTasks('grunt-sass');
 919      grunt.loadNpmTasks('grunt-eslint');
 920      grunt.loadNpmTasks('grunt-stylelint');
 921      grunt.loadNpmTasks('grunt-rollup');
 922  
 923      grunt.loadNpmTasks('grunt-jsdoc');
 924  
 925      // Rename the grunt-contrib-watch "watch" task because we're going to wrap it.
 926      grunt.renameTask('watch', 'watch-grunt');
 927  
 928      // Register JS tasks.
 929      grunt.registerTask('shifter', 'Run Shifter against the current directory', tasks.shifter);
 930      grunt.registerTask('gherkinlint', 'Run gherkinlint against the current directory', tasks.gherkinlint);
 931      grunt.registerTask('ignorefiles', 'Generate ignore files for linters', tasks.ignorefiles);
 932      grunt.registerTask('watch', 'Run tasks on file changes', tasks.watch);
 933      grunt.registerTask('yui', ['eslint:yui', 'shifter']);
 934      grunt.registerTask('amd', ['ignorefiles', 'eslint:amd', 'rollup']);
 935      grunt.registerTask('js', ['amd', 'yui']);
 936  
 937      // Register CSS tasks.
 938      registerStyleLintTasks(grunt, files, fullRunDir);
 939  
 940      // Register the startup task.
 941      grunt.registerTask('startup', 'Run the correct tasks for the current directory', tasks.startup);
 942  
 943      // Register the default task.
 944      grunt.registerTask('default', ['startup']);
 945  };