source: frontend/node_modules/webpack/lib/runtime/AutoPublicPathRuntimeModule.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");
const JavascriptModulesPlugin = require("../javascript/JavascriptModulesPlugin");
const { getUndoPath } = require("../util/identifier");

/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../Compilation")} Compilation */

class AutoPublicPathRuntimeModule extends RuntimeModule {
        constructor() {
                super("publicPath", RuntimeModule.STAGE_BASIC);
        }

        /**
         * Generates runtime code for this runtime module.
         * @returns {string | null} runtime code
         */
        generate() {
                const compilation = /** @type {Compilation} */ (this.compilation);
                const { scriptType, importMetaName, path, environment } =
                        compilation.outputOptions;
                const chunk = /** @type {Chunk} */ (this.chunk);
                const chunkName = compilation.getPath(
                        JavascriptModulesPlugin.getChunkFilenameTemplate(
                                chunk,
                                compilation.outputOptions
                        ),
                        {
                                chunk,
                                contentHashType: "javascript"
                        }
                );
                const undoPath = getUndoPath(
                        chunkName,
                        /** @type {string} */ (path),
                        false
                );

                const global = environment.globalThis
                        ? "globalThis"
                        : RuntimeGlobals.global;

                return Template.asString([
                        "var scriptUrl;",
                        scriptType === "module"
                                ? `if (typeof ${importMetaName}.url === "string") scriptUrl = ${importMetaName}.url`
                                : Template.asString([
                                                `if (${global}.importScripts) scriptUrl = ${global}.location + "";`,
                                                `var document = ${global}.document;`,
                                                "if (!scriptUrl && document) {",
                                                Template.indent([
                                                        // Technically we could use `document.currentScript instanceof window.HTMLScriptElement`,
                                                        // but an attacker could try to inject `<script>HTMLScriptElement = HTMLImageElement</script>`
                                                        // and use `<img name="currentScript" src="https://attacker.controlled.server/"></img>`
                                                        "if (document.currentScript && document.currentScript.tagName.toUpperCase() === 'SCRIPT')",
                                                        Template.indent("scriptUrl = document.currentScript.src;"),
                                                        "if (!scriptUrl) {",
                                                        Template.indent([
                                                                'var scripts = document.getElementsByTagName("script");',
                                                                "if(scripts.length) {",
                                                                Template.indent([
                                                                        "var i = scripts.length - 1;",
                                                                        "while (i > -1 && (!scriptUrl || !/^http(s?):/.test(scriptUrl))) scriptUrl = scripts[i--].src;"
                                                                ]),
                                                                "}"
                                                        ]),
                                                        "}"
                                                ]),
                                                "}"
                                        ]),
                        "// When supporting browsers where an automatic publicPath is not supported you must specify an output.publicPath manually via configuration",
                        '// or pass an empty string ("") and set the __webpack_public_path__ variable from your code to use your own logic.',
                        'if (!scriptUrl) throw new Error("Automatic publicPath is not supported in this browser");',
                        'scriptUrl = scriptUrl.replace(/^blob:/, "").replace(/#.*$/, "").replace(/\\?.*$/, "").replace(/\\/[^\\/]+$/, "/");',
                        !undoPath
                                ? `${RuntimeGlobals.publicPath} = scriptUrl;`
                                : `${RuntimeGlobals.publicPath} = scriptUrl + ${JSON.stringify(
                                                undoPath
                                        )};`
                ]);
        }
}

module.exports = AutoPublicPathRuntimeModule;