text: /*
   * grunt-contrib-concat
   * http://gruntjs.com/
   *
   * Copyright (c) 2014 "Cowboy" Ben Alman, contributors
   * Licensed under the MIT license.
   */
  
  'use strict';
  
  module.exports = function(grunt) {
  
    // Internal lib.
    var comment = require('./lib/comment').init(grunt);
    var chalk = require('chalk');
    var sourcemap = require('./lib/sourcemap').init(grunt);
  
    grunt.registerMultiTask('concat', 'Concatenate files.', function() {
      // Merge task-specific and/or target-specific options with these defaults.
      var options = this.options({
        separator: grunt.util.linefeed,
        banner: '',
        footer: '',
        stripBanners: false,
        process: false,
        sourceMap: false,
        sourceMapName: undefined,
        sourceMapStyle: 'embed'
      });
  
      // Normalize boolean options that accept options objects.
      if (options.stripBanners === true) { options.stripBanners = {}; }
      if (options.process === true) { options.process = {}; }
  
      // Process banner and footer.
      var banner = grunt.template.process(options.banner);
      var footer = grunt.template.process(options.footer);
  
      // Set a local variable for whether to build source maps or not.
      var sourceMap = options.sourceMap;
  
      // If content is not embedded and it will be modified, either exit or do
      // not make the source map.
      if (
        sourceMap && options.sourceMapStyle === 'link' &&
          (options.stripBanners || options.process)
      ) {
        // Warn and exit if --force isn't set.
        grunt.warn(
          'stripBanners or process option is enabled. ' +
          'Set sourceMapStyle option to \'embed\' or \'inline\'.'
        );
        // --force is set, continue on without the source map.
        grunt.log.warn('Skipping creation of source maps.');
        // Set sourceMap to false to keep maps from being constructed.
        sourceMap = false;
      }
  
      // Iterate over all src-dest file pairs.
      this.files.forEach(function(f) {
        // Initialize source map objects.
        var sourceMapHelper;
        if (sourceMap) {
          sourceMapHelper = sourcemap.helper(f, options);
          sourceMapHelper.add(banner);
        }
  
        // Concat banner + specified files + footer.
        var src = banner + f.src.filter(function(filepath) {
          // Warn on and remove invalid source files (if nonull was set).
          if (!grunt.file.exists(filepath)) {
            grunt.log.warn('Source file "' + filepath + '" not found.');
            return false;
          } else {
            return true;
          }
        }).map(function(filepath, i) {
          if (grunt.file.isDir(filepath)) {
            return;
          }
          // Read file source.
          var src = grunt.file.read(filepath);
          // Process files as templates if requested.
          if (typeof options.process === 'function') {
            src = options.process(src, filepath);
          } else if (options.process) {
            src = grunt.template.process(src, options.process);
          }
          // Strip banners if requested.
          if (options.stripBanners) {
            src = comment.stripBanner(src, options.stripBanners);
          }
          // Add the lines of this file to our map.
          if (sourceMapHelper) {
            src = sourceMapHelper.addlines(src, filepath);
            if (i < f.src.length - 1) {
              sourceMapHelper.add(options.separator);
            }
          }
          return src;
        }).join(options.separator) + footer;
  
        if (sourceMapHelper) {
          sourceMapHelper.add(footer);
          sourceMapHelper.write();
          // Add sourceMappingURL to the end.
          src += sourceMapHelper.url();
        }
  
        // Write the destination file.
        grunt.file.write(f.dest, src);
  
        // Print a success message.
        grunt.log.writeln('File ' + chalk.cyan(f.dest) + ' created.');
      });
    });
  
  };
  