"use strict";
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/* eslint-disable no-new-func */
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const acorn = require("acorn");
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const findGlobals = require("acorn-globals");
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const escodegen = require("escodegen");
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const jsGlobals = require("./browser/js-globals.json");
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// We can't use the default browserify vm shim because it doesn't work in a web worker.
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// "eval" is skipped because it's set to a function that calls `runInContext`:
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const jsGlobalEntriesToInstall = Object.entries(jsGlobals).filter(([name]) => name !== "eval" && name in global);
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exports.createContext = function (sandbox) {
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// TODO: This should probably use a symbol
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Object.defineProperty(sandbox, "__isVMShimContext", {
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value: true,
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writable: true,
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configurable: true,
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enumerable: false
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});
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for (const [globalName, globalPropDesc] of jsGlobalEntriesToInstall) {
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const propDesc = { ...globalPropDesc, value: global[globalName] };
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Object.defineProperty(sandbox, globalName, propDesc);
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}
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Object.defineProperty(sandbox, "eval", {
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value(code) {
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return exports.runInContext(code, sandbox);
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},
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writable: true,
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configurable: true,
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enumerable: false
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});
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};
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exports.isContext = function (sandbox) {
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return sandbox.__isVMShimContext;
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};
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exports.runInContext = function (code, contextifiedSandbox, options) {
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if (code === "this") {
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// Special case for during window creation.
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return contextifiedSandbox;
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}
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if (options === undefined) {
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options = {};
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}
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const comments = [];
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const tokens = [];
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const ast = acorn.parse(code, {
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allowReturnOutsideFunction: true,
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ranges: true,
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// collect comments in Esprima's format
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onComment: comments,
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// collect token ranges
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onToken: tokens
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});
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// make sure we keep comments
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escodegen.attachComments(ast, comments, tokens);
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const globals = findGlobals(ast);
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for (let i = 0; i < globals.length; ++i) {
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if (globals[i].name === "window" || globals[i].name === "this") {
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continue;
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}
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const { nodes } = globals[i];
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for (let j = 0; j < nodes.length; ++j) {
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const { type, name } = nodes[j];
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nodes[j].type = "MemberExpression";
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nodes[j].property = { name, type };
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nodes[j].computed = false;
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nodes[j].object = {
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name: "window",
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type: "Identifier"
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};
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}
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}
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const lastNode = ast.body[ast.body.length - 1];
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if (lastNode.type === "ExpressionStatement") {
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lastNode.type = "ReturnStatement";
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lastNode.argument = lastNode.expression;
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delete lastNode.expression;
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}
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const rewrittenCode = escodegen.generate(ast, { comment: true });
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const suffix = options.filename !== undefined ? "\n//# sourceURL=" + options.filename : "";
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return Function("window", rewrittenCode + suffix).bind(contextifiedSandbox)(contextifiedSandbox);
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};
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exports.Script = class VMShimScript {
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constructor(code, options) {
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this._code = code;
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this._options = options;
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}
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runInContext(sandbox, options) {
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return exports.runInContext(this._code, sandbox, { ...this._options, ...options });
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}
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};
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