126 lines
3.1 KiB
JavaScript
126 lines
3.1 KiB
JavaScript
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/* Copyright 2020 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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class ProxyHandler {
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constructor(dispatchEventName) {
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this.dispatchEventName = dispatchEventName;
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}
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get(obj, prop) {
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if (obj._isApp && prop === this.dispatchEventName) {
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// a backdoor to be able to call _dispatchEvent method
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// the value of 'dispatchEvent' is generated randomly
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// and injected in the code
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return obj._dispatchEvent.bind(obj);
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}
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// script may add some properties to the object
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if (prop in obj._expandos) {
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const val = obj._expandos[prop];
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if (typeof val === "function") {
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return val.bind(obj);
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}
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return val;
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}
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if (typeof prop === "string" && !prop.startsWith("_") && prop in obj) {
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// return only public properties
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// i.e. the ones not starting with a '_'
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const val = obj[prop];
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if (typeof val === "function") {
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return val.bind(obj);
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}
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return val;
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}
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return undefined;
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}
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set(obj, prop, value) {
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if (typeof prop === "string" && !prop.startsWith("_") && prop in obj) {
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const old = obj[prop];
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obj[prop] = value;
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if (obj._send && obj._id !== null && typeof old !== "function") {
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const data = { id: obj._id };
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data[prop] = value;
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// send the updated value to the other side
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obj._send(data);
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}
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} else {
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obj._expandos[prop] = value;
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}
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return true;
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}
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has(obj, prop) {
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return (
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prop in obj._expandos ||
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(typeof prop === "string" && !prop.startsWith("_") && prop in obj)
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);
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}
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getPrototypeOf(obj) {
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return null;
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}
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setPrototypeOf(obj, proto) {
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return false;
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}
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isExtensible(obj) {
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return true;
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}
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preventExtensions(obj) {
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return false;
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}
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getOwnPropertyDescriptor(obj, prop) {
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if (prop in obj._expandos) {
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return {
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configurable: true,
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enumerable: true,
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value: obj._expandos[prop],
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};
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}
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if (typeof prop === "string" && !prop.startsWith("_") && prop in obj) {
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return { configurable: true, enumerable: true, value: obj[prop] };
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}
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return undefined;
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}
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defineProperty(obj, key, descriptor) {
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Object.defineProperty(obj._expandos, key, descriptor);
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return true;
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}
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deleteProperty(obj, prop) {
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if (prop in obj._expandos) {
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delete obj._expandos[prop];
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}
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}
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ownKeys(obj) {
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const fromExpandos = Reflect.ownKeys(obj._expandos);
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const fromObj = Reflect.ownKeys(obj).filter(k => !k.startsWith("_"));
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return fromExpandos.concat(fromObj);
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}
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}
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export { ProxyHandler };
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