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// Copyright (C) 2017 Ecma International. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
description: |
Collection of functions used to safely verify the correctness of
property descriptors.
defines:
- verifyProperty
- verifyEqualTo
- verifyWritable
- verifyNotWritable
- verifyEnumerable
- verifyNotEnumerable
- verifyConfigurable
- verifyNotConfigurable
---*/
// @ts-check
/**
* @param {object} obj
* @param {string|symbol} name
* @param {PropertyDescriptor|undefined} desc
* @param {object} [options]
* @param {boolean} [options.restore]
*/
function verifyProperty(obj, name, desc, options) {
assert(
arguments.length > 2,
'verifyProperty should receive at least 3 arguments: obj, name, and descriptor'
);
var originalDesc = Object.getOwnPropertyDescriptor(obj, name);
var nameStr = String(name);
// Allows checking for undefined descriptor if it's explicitly given.
if (desc === undefined) {
assert.sameValue(
originalDesc,
undefined,
"obj['" + nameStr + "'] descriptor should be undefined"
);
// desc and originalDesc are both undefined, problem solved;
return true;
}
assert(
Object.prototype.hasOwnProperty.call(obj, name),
"obj should have an own property " + nameStr
);
assert.notSameValue(
desc,
null,
"The desc argument should be an object or undefined, null"
);
assert.sameValue(
typeof desc,
"object",
"The desc argument should be an object or undefined, " + String(desc)
);
var failures = [];
if (Object.prototype.hasOwnProperty.call(desc, 'value')) {
if (!isSameValue(desc.value, originalDesc.value)) {
failures.push("descriptor value should be " + desc.value);
}
}
if (Object.prototype.hasOwnProperty.call(desc, 'enumerable')) {
if (desc.enumerable !== originalDesc.enumerable ||
desc.enumerable !== isEnumerable(obj, name)) {
failures.push('descriptor should ' + (desc.enumerable ? '' : 'not ') + 'be enumerable');
}
}
if (Object.prototype.hasOwnProperty.call(desc, 'writable')) {
if (desc.writable !== originalDesc.writable ||
desc.writable !== isWritable(obj, name)) {
failures.push('descriptor should ' + (desc.writable ? '' : 'not ') + 'be writable');
}
}
if (Object.prototype.hasOwnProperty.call(desc, 'configurable')) {
if (desc.configurable !== originalDesc.configurable ||
desc.configurable !== isConfigurable(obj, name)) {
failures.push('descriptor should ' + (desc.configurable ? '' : 'not ') + 'be configurable');
}
}
assert(!failures.length, failures.join('; '));
if (options && options.restore) {
Object.defineProperty(obj, name, originalDesc);
}
return true;
}
function isConfigurable(obj, name) {
var hasOwnProperty = Object.prototype.hasOwnProperty;
try {
delete obj[name];
} catch (e) {
if (!(e instanceof TypeError)) {
throw new Test262Error("Expected TypeError, got " + e);
}
}
return !hasOwnProperty.call(obj, name);
}
function isEnumerable(obj, name) {
var stringCheck = false;
if (typeof name === "string") {
for (var x in obj) {
if (x === name) {
stringCheck = true;
break;
}
}
} else {
// skip it if name is not string, works for Symbol names.
stringCheck = true;
}
return stringCheck &&
Object.prototype.hasOwnProperty.call(obj, name) &&
Object.prototype.propertyIsEnumerable.call(obj, name);
}
function isSameValue(a, b) {
if (a === 0 && b === 0) return 1 / a === 1 / b;
if (a !== a && b !== b) return true;
return a === b;
}
var __isArray = Array.isArray;
function isWritable(obj, name, verifyProp, value) {
var unlikelyValue = __isArray(obj) && name === "length" ?
Math.pow(2, 32) - 1 :
"unlikelyValue";
var newValue = value || unlikelyValue;
var hadValue = Object.prototype.hasOwnProperty.call(obj, name);
var oldValue = obj[name];
var writeSucceeded;
try {
obj[name] = newValue;
} catch (e) {
if (!(e instanceof TypeError)) {
throw new Test262Error("Expected TypeError, got " + e);
}
}
writeSucceeded = isSameValue(obj[verifyProp || name], newValue);
// Revert the change only if it was successful (in other cases, reverting
// is unnecessary and may trigger exceptions for certain property
// configurations)
if (writeSucceeded) {
if (hadValue) {
obj[name] = oldValue;
} else {
delete obj[name];
}
}
return writeSucceeded;
}
function verifyEqualTo(obj, name, value) {
if (!isSameValue(obj[name], value)) {
throw new Test262Error("Expected obj[" + String(name) + "] to equal " + value +
", actually " + obj[name]);
}
}
function verifyWritable(obj, name, verifyProp, value) {
if (!verifyProp) {
assert(Object.getOwnPropertyDescriptor(obj, name).writable,
"Expected obj[" + String(name) + "] to have writable:true.");
}
if (!isWritable(obj, name, verifyProp, value)) {
throw new Test262Error("Expected obj[" + String(name) + "] to be writable, but was not.");
}
}
function verifyNotWritable(obj, name, verifyProp, value) {
if (!verifyProp) {
assert(!Object.getOwnPropertyDescriptor(obj, name).writable,
"Expected obj[" + String(name) + "] to have writable:false.");
}
if (isWritable(obj, name, verifyProp)) {
throw new Test262Error("Expected obj[" + String(name) + "] NOT to be writable, but was.");
}
}
function verifyEnumerable(obj, name) {
assert(Object.getOwnPropertyDescriptor(obj, name).enumerable,
"Expected obj[" + String(name) + "] to have enumerable:true.");
if (!isEnumerable(obj, name)) {
throw new Test262Error("Expected obj[" + String(name) + "] to be enumerable, but was not.");
}
}
function verifyNotEnumerable(obj, name) {
assert(!Object.getOwnPropertyDescriptor(obj, name).enumerable,
"Expected obj[" + String(name) + "] to have enumerable:false.");
if (isEnumerable(obj, name)) {
throw new Test262Error("Expected obj[" + String(name) + "] NOT to be enumerable, but was.");
}
}
function verifyConfigurable(obj, name) {
assert(Object.getOwnPropertyDescriptor(obj, name).configurable,
"Expected obj[" + String(name) + "] to have configurable:true.");
if (!isConfigurable(obj, name)) {
throw new Test262Error("Expected obj[" + String(name) + "] to be configurable, but was not.");
}
}
function verifyNotConfigurable(obj, name) {
assert(!Object.getOwnPropertyDescriptor(obj, name).configurable,
"Expected obj[" + String(name) + "] to have configurable:false.");
if (isConfigurable(obj, name)) {
throw new Test262Error("Expected obj[" + String(name) + "] NOT to be configurable, but was.");
}
}