source: trip-planner-front/node_modules/resolve-url-loader/lib/value-processor.js@ fa375fe

Last change on this file since fa375fe was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1/*
2 * MIT License http://opensource.org/licenses/MIT
3 * Author: Ben Holloway @bholloway
4 */
5'use strict';
6
7var path = require('path'),
8 loaderUtils = require('loader-utils');
9
10/**
11 * Create a value processing function for a given file path.
12 *
13 * @param {function(Object):string} join The inner join function
14 * @param {string} root The loader options.root value where given
15 * @param {string} directory The directory of the file webpack is currently processing
16 * @return {function} value processing function
17 */
18function valueProcessor({ join, root, directory }) {
19 var URL_STATEMENT_REGEX = /(url\s*\(\s*)(?:(['"])((?:(?!\2).)*)(\2)|([^'"](?:(?!\)).)*[^'"]))(\s*\))/g,
20 QUERY_REGEX = /([?#])/g;
21
22 /**
23 * Process the given CSS declaration value.
24 *
25 * @param {string} value A declaration value that may or may not contain a url() statement
26 * @param {function(number):Object} getPathsAtChar Given an offset in the declaration value get a
27 * list of possible absolute path strings
28 */
29 return function transformValue(value, getPathsAtChar) {
30
31 // allow multiple url() values in the declaration
32 // split by url statements and process the content
33 // additional capture groups are needed to match quotations correctly
34 // escaped quotations are not considered
35 return value
36 .split(URL_STATEMENT_REGEX)
37 .map(initialise)
38 .map(eachSplitOrGroup)
39 .join('');
40
41 /**
42 * Ensure all capture group tokens are a valid string.
43 *
44 * @param {string|void} token A capture group or uncaptured token
45 * @returns {string}
46 */
47 function initialise(token) {
48 return typeof token === 'string' ? token : '';
49 }
50
51 /**
52 * An Array reduce function that accumulates string length.
53 */
54 function accumulateLength(accumulator, element) {
55 return accumulator + element.length;
56 }
57
58 /**
59 * Encode the content portion of <code>url()</code> statements.
60 * There are 6 capture groups in the split making every 7th unmatched.
61 *
62 * @param {string} element A single split item
63 * @param {number} i The index of the item in the split
64 * @param {Array} arr The array of split values
65 * @returns {string} Every 3 or 5 items is an encoded url everything else is as is
66 */
67 function eachSplitOrGroup(element, i, arr) {
68
69 // the content of the url() statement is either in group 3 or group 5
70 var mod = i % 7;
71
72 // only one of the capture groups 3 or 5 will match the other will be falsey
73 if (element && ((mod === 3) || (mod === 5))) {
74
75 // calculate the offset of the match from the front of the string
76 var position = arr.slice(0, i - mod + 1).reduce(accumulateLength, 0);
77
78 // detect quoted url and unescape backslashes
79 var before = arr[i - 1],
80 after = arr[i + 1],
81 isQuoted = (before === after) && ((before === '\'') || (before === '"')),
82 unescaped = isQuoted ? element.replace(/\\{2}/g, '\\') : element;
83
84 // split into uri and query/hash and then determine if the uri is some type of file
85 var split = unescaped.split(QUERY_REGEX),
86 uri = split[0],
87 query = split.slice(1).join(''),
88 isRelative = testIsRelative(uri),
89 isAbsolute = testIsAbsolute(uri);
90
91 // file like URIs are processed but not all URIs are files
92 if (isRelative || isAbsolute) {
93 var bases = getPathsAtChar(position), // construct iterator as late as possible in case sourcemap invalid
94 absolute = join({ uri, query, isAbsolute, bases });
95
96 if (typeof absolute === 'string') {
97 var relative = path.relative(directory, absolute)
98 .replace(/\\/g, '/'); // #6 - backslashes are not legal in URI
99
100 return loaderUtils.urlToRequest(relative + query);
101 }
102 }
103 }
104
105 // everything else, including parentheses and quotation (where present) and media statements
106 return element;
107 }
108 };
109
110 /**
111 * The loaderUtils.isUrlRequest() doesn't support windows absolute paths on principle. We do not subscribe to that
112 * dogma so we add path.isAbsolute() check to allow them.
113 *
114 * We also eliminate module relative (~) paths.
115 *
116 * @param {string|undefined} uri A uri string possibly empty or undefined
117 * @return {boolean} True for relative uri
118 */
119 function testIsRelative(uri) {
120 return !!uri && loaderUtils.isUrlRequest(uri, false) && !path.isAbsolute(uri) && (uri.indexOf('~') !== 0);
121 }
122
123 /**
124 * The loaderUtils.isUrlRequest() doesn't support windows absolute paths on principle. We do not subscribe to that
125 * dogma so we add path.isAbsolute() check to allow them.
126 *
127 * @param {string|undefined} uri A uri string possibly empty or undefined
128 * @return {boolean} True for absolute uri
129 */
130 function testIsAbsolute(uri) {
131 return !!uri && (typeof root === 'string') && loaderUtils.isUrlRequest(uri, root) &&
132 (/^\//.test(uri) || path.isAbsolute(uri));
133 }
134}
135
136module.exports = valueProcessor;
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