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/*
* Copyright (C) 2020 Alex Yatskov <alex@foosoft.net>
* Author: Alex Yatskov <alex@foosoft.net>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
const fs = require('fs');
const vm = require('vm');
const path = require('path');
const assert = require('assert');
function getContextEnvironmentRecords(context, names) {
// Enables export of values from the declarative environment record
if (!Array.isArray(names) || names.length === 0) {
return [];
}
let scriptSource = '(() => {\n "use strict";\n const results = [];';
for (const name of names) {
scriptSource += `\n try { results.push(${name}); } catch (e) { results.push(void 0); }`;
}
scriptSource += '\n return results;\n})();';
const script = new vm.Script(scriptSource, {filename: 'getContextEnvironmentRecords'});
const contextHasNames = Object.prototype.hasOwnProperty.call(context, 'names');
const contextNames = context.names;
context.names = names;
const results = script.runInContext(context, {});
if (contextHasNames) {
context.names = contextNames;
} else {
delete context.names;
}
return Array.from(results);
}
function isDeepStrictEqual(val1, val2) {
if (val1 === val2) { return true; }
if (Array.isArray(val1)) {
if (Array.isArray(val2)) {
return isArrayDeepStrictEqual(val1, val2);
}
} else if (typeof val1 === 'object' && val1 !== null) {
if (typeof val2 === 'object' && val2 !== null) {
return isObjectDeepStrictEqual(val1, val2);
}
}
return false;
}
function isArrayDeepStrictEqual(val1, val2) {
const ii = val1.length;
if (ii !== val2.length) { return false; }
for (let i = 0; i < ii; ++i) {
if (!isDeepStrictEqual(val1[i], val2[i])) {
return false;
}
}
return true;
}
function isObjectDeepStrictEqual(val1, val2) {
const keys1 = Object.keys(val1);
const keys2 = Object.keys(val2);
if (keys1.length !== keys2.length) { return false; }
const keySet = new Set(keys1);
for (const key of keys2) {
if (!keySet.delete(key)) { return false; }
}
for (const key of keys1) {
if (!isDeepStrictEqual(val1[key], val2[key])) {
return false;
}
}
const tag1 = Object.prototype.toString.call(val1);
const tag2 = Object.prototype.toString.call(val2);
if (tag1 !== tag2) { return false; }
return true;
}
function deepStrictEqual(actual, expected) {
try {
// This will fail on prototype === comparison on cross context objects
assert.deepStrictEqual(actual, expected);
} catch (e) {
if (!isDeepStrictEqual(actual, expected)) {
throw e;
}
}
}
class VM {
constructor(context={}) {
this._context = vm.createContext(context);
this._assert = {
deepStrictEqual
};
}
get context() {
return this._context;
}
get assert() {
return this._assert;
}
get(names) {
if (typeof names === 'string') {
return getContextEnvironmentRecords(this._context, [names])[0];
} else if (Array.isArray(names)) {
return getContextEnvironmentRecords(this._context, names);
} else {
throw new Error('Invalid argument');
}
}
set(values) {
if (typeof values === 'object' && values !== null) {
Object.assign(this._context, values);
} else {
throw new Error('Invalid argument');
}
}
execute(fileNames) {
const single = !Array.isArray(fileNames);
if (single) {
fileNames = [fileNames];
}
const results = [];
for (const fileName of fileNames) {
const absoluteFileName = path.resolve(__dirname, '..', 'ext', fileName);
const source = fs.readFileSync(absoluteFileName, {encoding: 'utf8'});
const script = new vm.Script(source, {filename: absoluteFileName});
results.push(script.runInContext(this._context, {}));
}
return single ? results[0] : results;
}
}
module.exports = {
VM
};
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