1. module resolve-url-loader
   1. function resolve-url-loader (content, sourceMap)

module resolve-url-loader

function resolve-url-loader (content, sourceMap)

• description and source-code

  function resolveUrlLoader(content, sourceMap) {
    /* jshint validthis:true */
  
    // details of the file being processed
    var loader   = this,
        filePath = path.dirname(loader.resourcePath);
  
    // webpack 1: prefer loader query, else options object
    // webpack 2; prefer loader options
    var options = defaults(loaderUtils.getOptions(loader), loader.options[camelcase(PACKAGE_NAME)], {
      absolute : false,
      sourceMap: false,
      fail     : false,
      silent   : false,
      keepQuery: false,
      debug    : false,
      root     : null
    });
  
    // validate root directory
    var resolvedRoot = (typeof options.root === 'string') && path.resolve(options.root) || undefined,
        isValidRoot  = resolvedRoot && fs.existsSync(resolvedRoot);
    if (options.root && !isValidRoot) {
      return handleException('"root" option does not resolve to a valid path');
    }
  
    // loader result is cacheable
    loader.cacheable();
  
    // incoming source-map
    var sourceMapConsumer, contentWithMap, sourceRoot;
    if (sourceMap) {
  
      // support non-standard string encoded source-map (per less-loader)
      if (typeof sourceMap === 'string') {
        try {
          sourceMap = JSON.parse(sourceMap);
        }
        catch (exception) {
          return handleException('source-map error', 'cannot parse source-map string (from less-loader?)');
        }
      }
  
      // Note the current sourceRoot before it is removed
      //  later when we go back to relative paths, we need to add it again
      sourceRoot = sourceMap.sourceRoot;
  
      // leverage adjust-sourcemap-loader's codecs to avoid having to make any assumptions about the sourcemap
      //  historically this is a regular source of breakage
      var absSourceMap;
      try {
        absSourceMap = adjustSourceMap(this, {format: 'absolute'}, sourceMap);
      }
      catch (exception) {
        return handleException('source-map error', exception.message);
      }
  
      // prepare the adjusted sass source-map for later look-ups
      sourceMapConsumer = new SourceMapConsumer(absSourceMap);
  
      // embed source-map in css for rework-css to use
      contentWithMap = content + convert.fromObject(absSourceMap).toComment({multiline: true});
    }
    // absent source map
    else {
      contentWithMap = content;
    }
  
    // process
    //  rework-css will throw on css syntax errors
    var useMap = loader.sourceMap || options.sourceMap,
        reworked;
    try {
      reworked = rework(contentWithMap, {source: loader.resourcePath})
        .use(reworkPlugin)
        .toString({
          sourcemap        : useMap,
          sourcemapAsObject: useMap
        });
    }
      //  fail gracefully
    catch (exception) {
      return handleException('CSS error', exception);
    }
  
    // complete with source-map
    if (useMap) {
  
      // source-map sources seem to be relative to the file being processed
      absoluteToRelative(reworked.map.sources, path.resolve(filePath, sourceRoot || '.'));
  
      // Set source root again
      reworked.map.sourceRoot = sourceRoot;
  
      // need to use callback when there are multiple arguments
      loader.callback(null, reworked.code, reworked.map);
    }
    // complete without source-map
    else {
      return reworked;
    }
  
    /**
     * Push an error for the given exception and return the original content.
     * @param {string} label Summary of the error
     * @param {string|Error} [exception] Optional extended error details
     * @returns {string} The original CSS content
     */
    function handleException(label, exception) {
      var rest = (typeof exception === 'string') ? [exception] :
                 (exception instanceof Error) ? [exception.message, exception.stack.split('\n')[1].trim()] :
                 [];
      var message = '  resolve-url-loader cannot operate: ' + [label].concat(rest).filter(Boolean).join('\n  ');
      if (options.fail) {
        loader.emitError(message);
      }
      else if (!options.silent) {
        loader.emitWarning(message);
      }
      return content;
    }
  
    /**
     * Plugin for css rework that follows SASS transpilation
     * @param {object} stylesheet AST for the CSS output from SASS
     */
    function reworkPlugin(stylesheet) {
      var URL_ ...

• example usage

  n/a