544 lines
14 KiB
JavaScript
544 lines
14 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const { readFile } = require("fs");
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const loadLoader = require("./loadLoader");
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const HASH_ESCAPE_REGEXP = /#/g;
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// UTF-8 encoding of the BOM: EF BB BF
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const UTF8_BOM_0 = 0xef;
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const UTF8_BOM_1 = 0xbb;
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const UTF8_BOM_2 = 0xbf;
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function utf8BufferToString(buf) {
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// Detect and skip the BOM at the buffer level to avoid materializing the
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// prefix as JS string and then re-slicing it.
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if (
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buf.length >= 3 &&
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buf[0] === UTF8_BOM_0 &&
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buf[1] === UTF8_BOM_1 &&
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buf[2] === UTF8_BOM_2
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) {
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return buf.toString("utf8", 3);
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}
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return buf.toString("utf8");
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}
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/**
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* Escape `#` characters with a preceding `\0` byte. Short-circuits when the input contains no `#`, avoiding the regex scan for the common case.
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* @param {string} str input string
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* @returns {string} escaped string
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*/
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function escapeHash(str) {
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return str.includes("#") ? str.replace(HASH_ESCAPE_REGEXP, "\0#") : str;
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}
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const PATH_QUERY_FRAGMENT_REGEXP =
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/^((?:\0.|[^?#\0])*)(\?(?:\0.|[^#\0])*)?(#.*)?$/;
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const ZERO_ESCAPE_REGEXP = /\0(.)/g;
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/**
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* @param {string} identifier identifier
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* @returns {[string, string, string]} parsed identifier
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*/
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function parseIdentifier(identifier) {
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// Fast path for inputs that don't use \0 escaping.
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const firstEscape = identifier.indexOf("\0");
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if (firstEscape < 0) {
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const queryStart = identifier.indexOf("?");
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const fragmentStart = identifier.indexOf("#");
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if (fragmentStart < 0) {
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if (queryStart < 0) {
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// No fragment, no query
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return [identifier, "", ""];
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}
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// Query, no fragment
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return [
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identifier.slice(0, queryStart),
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identifier.slice(queryStart),
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"",
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];
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}
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if (queryStart < 0 || fragmentStart < queryStart) {
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// Fragment, no query
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return [
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identifier.slice(0, fragmentStart),
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"",
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identifier.slice(fragmentStart),
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];
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}
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// Query and fragment
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return [
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identifier.slice(0, queryStart),
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identifier.slice(queryStart, fragmentStart),
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identifier.slice(fragmentStart),
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];
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}
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const match = PATH_QUERY_FRAGMENT_REGEXP.exec(identifier);
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return [
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match[1].replace(ZERO_ESCAPE_REGEXP, "$1"),
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match[2] ? match[2].replace(ZERO_ESCAPE_REGEXP, "$1") : "",
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match[3] || "",
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];
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}
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function dirname(path) {
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if (path === "/") return "/";
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const i = path.lastIndexOf("/");
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const j = path.lastIndexOf("\\");
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const i2 = path.indexOf("/");
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const j2 = path.indexOf("\\");
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const idx = i > j ? i : j;
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const idx2 = i > j ? i2 : j2;
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if (idx < 0) return path;
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if (idx === idx2) return path.slice(0, idx + 1);
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return path.slice(0, idx);
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}
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function createLoaderObject(loader) {
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const obj = {
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path: null,
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query: null,
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fragment: null,
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options: null,
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ident: null,
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normal: null,
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pitch: null,
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raw: null,
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data: null,
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pitchExecuted: false,
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normalExecuted: false,
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};
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Object.defineProperty(obj, "request", {
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enumerable: true,
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get() {
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return escapeHash(obj.path) + escapeHash(obj.query) + obj.fragment;
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},
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set(value) {
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if (typeof value === "string") {
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const [path, query, fragment] = parseIdentifier(value);
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obj.path = path;
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obj.query = query;
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obj.fragment = fragment;
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obj.options = undefined;
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obj.ident = undefined;
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return;
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}
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if (!value.loader) {
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throw new Error(
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`request should be a string or object with loader and options (${JSON.stringify(
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value
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)})`
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);
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}
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const { loader: path, fragment, type, options, ident } = value;
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obj.path = path;
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obj.fragment = fragment || "";
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obj.type = type;
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obj.options = options;
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obj.ident = ident;
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if (options === null || options === undefined) {
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obj.query = "";
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} else if (typeof options === "string") {
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obj.query = `?${options}`;
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} else if (ident) {
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obj.query = `??${ident}`;
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} else if (typeof options === "object" && options.ident) {
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obj.query = `??${options.ident}`;
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} else {
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obj.query = `?${JSON.stringify(options)}`;
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}
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},
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});
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obj.request = loader;
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if (Object.preventExtensions) {
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Object.preventExtensions(obj);
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}
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return obj;
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}
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function runSyncOrAsync(fn, context, args, callback) {
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let isSync = true;
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let isDone = false;
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let isError = false; // internal error
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let reportedError = false;
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// eslint-disable-next-line func-name-matching
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const innerCallback = (context.callback = function innerCallback(
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...callbackArgs
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) {
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if (isDone) {
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if (reportedError) return; // ignore
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throw new Error("callback(): The callback was already called.");
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}
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isDone = true;
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isSync = false;
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try {
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callback(...callbackArgs);
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} catch (err) {
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isError = true;
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throw err;
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}
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});
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context.async = function async() {
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if (isDone) {
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if (reportedError) return; // ignore
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throw new Error("async(): The callback was already called.");
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}
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isSync = false;
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return innerCallback;
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};
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try {
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const result = (function LOADER_EXECUTION() {
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return fn.apply(context, args);
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})();
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if (isSync) {
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isDone = true;
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if (result === undefined) return callback();
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if (
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result &&
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typeof result === "object" &&
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typeof result.then === "function"
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) {
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return result.then((r) => {
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callback(null, r);
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}, callback);
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}
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return callback(null, result);
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}
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} catch (err) {
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if (isError) throw err;
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if (isDone) {
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// loader is already "done", so we cannot use the callback function
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// for better debugging we print the error on the console
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if (typeof err === "object" && err.stack) {
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// eslint-disable-next-line no-console
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console.error(err.stack);
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} else {
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// eslint-disable-next-line no-console
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console.error(err);
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}
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return;
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}
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isDone = true;
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reportedError = true;
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callback(err);
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}
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}
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function convertArgs(args, raw) {
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if (!raw && Buffer.isBuffer(args[0])) {
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args[0] = utf8BufferToString(args[0]);
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} else if (raw && typeof args[0] === "string") {
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args[0] = Buffer.from(args[0], "utf8");
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}
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}
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function iterateNormalLoaders(options, loaderContext, args, callback) {
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while (loaderContext.loaderIndex >= 0) {
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const currentLoaderObject =
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loaderContext.loaders[loaderContext.loaderIndex];
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if (currentLoaderObject.normalExecuted) {
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loaderContext.loaderIndex--;
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continue;
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}
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const fn = currentLoaderObject.normal;
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currentLoaderObject.normalExecuted = true;
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if (!fn) continue;
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convertArgs(args, currentLoaderObject.raw);
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return runSyncOrAsync(fn, loaderContext, args, (err, ...nextArgs) => {
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if (err) return callback(err);
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iterateNormalLoaders(options, loaderContext, nextArgs, callback);
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});
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}
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return callback(null, args);
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}
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function processResource(options, loaderContext, callback) {
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// set loader index to last loader
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loaderContext.loaderIndex = loaderContext.loaders.length - 1;
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const { resourcePath } = loaderContext;
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if (!resourcePath) {
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return iterateNormalLoaders(options, loaderContext, [null], callback);
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}
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options.processResource(loaderContext, resourcePath, (err, ...args) => {
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if (err) return callback(err);
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// eslint-disable-next-line prefer-destructuring
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options.resourceBuffer = args[0];
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iterateNormalLoaders(options, loaderContext, args, callback);
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});
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}
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function iteratePitchingLoaders(options, loaderContext, callback) {
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// Iterative walk over already-pitched loaders without recursion.
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while (loaderContext.loaderIndex < loaderContext.loaders.length) {
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const currentLoaderObject =
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loaderContext.loaders[loaderContext.loaderIndex];
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if (currentLoaderObject.pitchExecuted) {
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loaderContext.loaderIndex++;
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continue;
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}
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return loadLoader(currentLoaderObject, (err) => {
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if (err) {
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loaderContext.cacheable(false);
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return callback(err);
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}
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const fn = currentLoaderObject.pitch;
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currentLoaderObject.pitchExecuted = true;
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if (!fn) return iteratePitchingLoaders(options, loaderContext, callback);
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runSyncOrAsync(
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fn,
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loaderContext,
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[
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loaderContext.remainingRequest,
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loaderContext.previousRequest,
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(currentLoaderObject.data = {}),
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],
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(pitchErr, ...args) => {
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if (pitchErr) return callback(pitchErr);
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// Determine whether to continue the pitching process based on
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// argument values (as opposed to argument presence) in order
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// to support synchronous and asynchronous usages. Inline loop
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// avoids allocating a predicate closure per pitched loader.
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let hasArg = false;
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for (let i = 0; i < args.length; i++) {
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if (args[i] !== undefined) {
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hasArg = true;
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break;
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}
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}
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if (hasArg) {
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loaderContext.loaderIndex--;
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iterateNormalLoaders(options, loaderContext, args, callback);
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} else {
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iteratePitchingLoaders(options, loaderContext, callback);
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}
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}
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);
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});
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}
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// Reached the end: move on to processing the resource itself.
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return processResource(options, loaderContext, callback);
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}
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/**
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* Join loader requests into a single `!`-separated string for a range of loader indices.
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* @param {object[]} loaders loader objects
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* @param {number} start inclusive start index
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* @param {number} end exclusive end index
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* @param {string} resource resource string
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* @returns {string} joined request
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*/
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function joinRequests(loaders, start, end, resource) {
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let result = "";
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for (let i = start; i < end; i++) {
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result += `${loaders[i].request}!`;
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}
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return result + resource;
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}
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module.exports.getContext = function getContext(resource) {
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const [path] = parseIdentifier(resource);
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return dirname(path);
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};
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module.exports.runLoaders = function runLoaders(options, callback) {
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// read options
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const resource = options.resource || "";
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const loaderContext = options.context || {};
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const processResourceFn =
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options.processResource ||
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((readResource, context, res, cb) => {
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context.addDependency(res);
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readResource(res, cb);
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}).bind(null, options.readResource || readFile);
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const splittedResource = resource && parseIdentifier(resource);
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const resourcePath = splittedResource ? splittedResource[0] : "";
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const resourceQuery = splittedResource ? splittedResource[1] : "";
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const resourceFragment = splittedResource ? splittedResource[2] : "";
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const contextDirectory = resourcePath ? dirname(resourcePath) : null;
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// execution state
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let requestCacheable = true;
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const fileDependencies = [];
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const contextDependencies = [];
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const missingDependencies = [];
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// prepare loader objects
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const loaders = (options.loaders || []).map(createLoaderObject);
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loaderContext.context = contextDirectory;
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loaderContext.loaderIndex = 0;
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loaderContext.loaders = loaders;
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loaderContext.resourcePath = resourcePath;
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loaderContext.resourceQuery = resourceQuery;
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loaderContext.resourceFragment = resourceFragment;
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loaderContext.async = null;
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loaderContext.callback = null;
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loaderContext.cacheable = (flag) => {
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if (flag === false) {
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requestCacheable = false;
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}
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};
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loaderContext.dependency = loaderContext.addDependency = (file) => {
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fileDependencies.push(file);
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};
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loaderContext.addContextDependency = (context) => {
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contextDependencies.push(context);
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};
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loaderContext.addMissingDependency = (context) => {
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missingDependencies.push(context);
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};
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loaderContext.getDependencies = () => fileDependencies.slice();
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loaderContext.getContextDependencies = () => contextDependencies.slice();
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loaderContext.getMissingDependencies = () => missingDependencies.slice();
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loaderContext.clearDependencies = () => {
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fileDependencies.length = 0;
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contextDependencies.length = 0;
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missingDependencies.length = 0;
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requestCacheable = true;
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};
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Object.defineProperty(loaderContext, "resource", {
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enumerable: true,
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get() {
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return (
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escapeHash(loaderContext.resourcePath) +
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escapeHash(loaderContext.resourceQuery) +
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loaderContext.resourceFragment
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);
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},
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set(value) {
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const splitted = value && parseIdentifier(value);
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loaderContext.resourcePath = splitted ? splitted[0] : "";
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loaderContext.resourceQuery = splitted ? splitted[1] : "";
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loaderContext.resourceFragment = splitted ? splitted[2] : "";
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},
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});
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Object.defineProperty(loaderContext, "request", {
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enumerable: true,
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get() {
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return joinRequests(
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loaders,
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0,
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loaders.length,
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loaderContext.resource || ""
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);
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},
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});
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Object.defineProperty(loaderContext, "remainingRequest", {
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enumerable: true,
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get() {
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return joinRequests(
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loaders,
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loaderContext.loaderIndex + 1,
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loaders.length,
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loaderContext.resource
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);
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},
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});
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Object.defineProperty(loaderContext, "currentRequest", {
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enumerable: true,
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get() {
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return joinRequests(
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loaders,
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loaderContext.loaderIndex,
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loaders.length,
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loaderContext.resource
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);
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},
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});
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Object.defineProperty(loaderContext, "previousRequest", {
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enumerable: true,
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get() {
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const end = loaderContext.loaderIndex;
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if (end === 0) return "";
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let result = loaders[0].request;
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for (let i = 1; i < end; i++) {
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result += `!${loaders[i].request}`;
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}
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return result;
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},
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});
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Object.defineProperty(loaderContext, "query", {
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enumerable: true,
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get() {
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const entry = loaders[loaderContext.loaderIndex];
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return entry.options && typeof entry.options === "object"
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? entry.options
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: entry.query;
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},
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});
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Object.defineProperty(loaderContext, "data", {
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enumerable: true,
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get() {
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return loaders[loaderContext.loaderIndex].data;
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},
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});
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// finish loader context
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if (Object.preventExtensions) {
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Object.preventExtensions(loaderContext);
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}
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const processOptions = {
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resourceBuffer: null,
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processResource: processResourceFn,
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};
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iteratePitchingLoaders(processOptions, loaderContext, (err, result) => {
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if (err) {
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return callback(err, {
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cacheable: requestCacheable,
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fileDependencies,
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contextDependencies,
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missingDependencies,
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});
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}
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callback(null, {
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result,
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resourceBuffer: processOptions.resourceBuffer,
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cacheable: requestCacheable,
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fileDependencies,
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contextDependencies,
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missingDependencies,
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});
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});
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};
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