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/*
* MIT License http://opensource.org/licenses/MIT
* Author: Ben Holloway @bholloway
*/
'use strict';
var path = require('path'),
loaderUtils = require('loader-utils');
/**
* Create a value processing function for a given file path.
*
* @param {string} filename The current file being processed
* @param {{absolute:string, keepQuery:boolean, join:function, root:string}} options Options hash
* @return {function} value processing function
*/
function valueProcessor(filename, options) {
var URL_STATEMENT_REGEX = /(url\s*\()\s*(?:(['"])((?:(?!\2).)*)(\2)|([^'"](?:(?!\)).)*[^'"]))\s*(\))/g;
var directory = path.dirname(filename);
var join = options.join(filename, options);
/**
* Process the given CSS declaration value.
*
* @param {string} value A declaration value that may or may not contain a url() statement
* @param {string|Iterator.<string>} candidate An absolute path that may be the correct base or an Iterator thereof
*/
return function transformValue(value, candidate) {
// allow multiple url() values in the declaration
// split by url statements and process the content
// additional capture groups are needed to match quotations correctly
// escaped quotations are not considered
return value
.split(URL_STATEMENT_REGEX)
.map(eachSplitOrGroup)
.join('');
/**
* Encode the content portion of <code>url()</code> statements.
* There are 4 capture groups in the split making every 5th unmatched.
*
* @param {string} token A single split item
* @param {number} i The index of the item in the split
* @param {Array} arr The array of split values
* @returns {string} Every 3 or 5 items is an encoded url everything else is as is
*/
function eachSplitOrGroup(token, i, arr) {
// we can get groups as undefined under certain match circumstances
var initialised = token || '';
// the content of the url() statement is either in group 3 or group 5
var mod = i % 7;
if ((mod === 3) || (mod === 5)) {
// detect quoted url and unescape backslashes
var before = arr[i - 1],
after = arr[i + 1],
isQuoted = (before === after) && ((before === '\'') || (before === '"')),
unescaped = isQuoted ? initialised.replace(/\\{2}/g, '\\') : initialised;
// split into uri and query/hash and then find the absolute path to the uri
var split = unescaped.split(/([?#])/g),
uri = split[0],
absolute = testIsRelative(uri) && join(uri, candidate) || testIsAbsolute(uri) && join(uri),
query = options.keepQuery ? split.slice(1).join('') : '';
// use the absolute path in absolute mode or else relative path (or default to initialised)
// #6 - backslashes are not legal in URI
if (!absolute) {
return initialised;
} else if (options.absolute) {
return absolute.replace(/\\/g, '/') + query;
} else {
return loaderUtils.urlToRequest(
path.relative(directory, absolute).replace(/\\/g, '/') + query
);
}
}
// everything else, including parentheses and quotation (where present) and media statements
else {
return initialised;
}
}
};
/**
* The loaderUtils.isUrlRequest() doesn't support windows absolute paths on principle. We do not subscribe to that
* dogma so we add path.isAbsolute() check to allow them.
*
* We also eliminate module relative (~) paths.
*
* @param {string|undefined} uri A uri string possibly empty or undefined
* @return {boolean} True for relative uri
*/
function testIsRelative(uri) {
return !!uri && loaderUtils.isUrlRequest(uri, false) && !path.isAbsolute(uri) && (uri.indexOf('~') !== 0);
}
/**
* The loaderUtils.isUrlRequest() doesn't support windows absolute paths on principle. We do not subscribe to that
* dogma so we add path.isAbsolute() check to allow them.
*
* @param {string|undefined} uri A uri string possibly empty or undefined
* @return {boolean} True for absolute uri
*/
function testIsAbsolute(uri) {
return !!uri && (typeof options.root === 'string') && loaderUtils.isUrlRequest(uri, options.root) &&
(/^\//.test(uri) || path.isAbsolute(uri));
}
}
module.exports = valueProcessor;