Source/WebInspectorUI/UserInterface/Protocol/RemoteObject.js - WebKit - Git at Google

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 WI.RemoteObject = class RemoteObject
 {
     constructor(target, objectId, type, subtype, value, description, size, classPrototype, className, preview)
     {
         console.assert(type);
         console.assert(!preview || preview instanceof WI.ObjectPreview);
         console.assert(!target || target instanceof WI.Target);

         this._target = target || WI.mainTarget;
         this._type = type;
         this._subtype = subtype;

         if (objectId) {
             // Object, Function, or Symbol.
             console.assert(!subtype || typeof subtype === "string");
             console.assert(!description || typeof description === "string");
             console.assert(!value);

             this._objectId = objectId;
             this._description = description || "";
             this._hasChildren = type !== "symbol";
             this._size = size;
             this._classPrototype = classPrototype;
             this._preview = preview;

             if (subtype === "class") {
                 this._functionDescription = this._description;
                 this._description = "class " + className;
             }
         } else {
             // Primitive, BigInt, or null.
             console.assert(type !== "object" || value === null);
             console.assert(!preview);

             this._description = description || (value + "");
             this._hasChildren = false;
             this._value = value;

             if (type === "bigint") {
                 console.assert(value === undefined);
                 console.assert(description.endsWith("n"));
                 if (window.BigInt)
                     this._value = BigInt(description.substring(0, description.length - 1));
                 else
                     this._value = `${description} [BigInt Not Enabled in Web Inspector]`;
             }
         }
     }

     // Static

     static createFakeRemoteObject()
     {
         return new WI.RemoteObject(undefined, WI.RemoteObject.FakeRemoteObjectId, "object");
     }

     static fromPrimitiveValue(value)
     {
         return new WI.RemoteObject(undefined, undefined, typeof value, undefined, value, undefined, undefined, undefined, undefined);
     }

     static createBigIntFromDescriptionString(description)
     {
         console.assert(description.endsWith("n"));

         return new WI.RemoteObject(undefined, undefined, "bigint", undefined, undefined, description, undefined, undefined, undefined);
     }

     static fromPayload(payload, target)
     {
         console.assert(typeof payload === "object", "Remote object payload should only be an object");

         if (payload.subtype === "array") {
             // COMPATIBILITY (iOS 8): Runtime.RemoteObject did not have size property,
             // instead it was tacked onto the end of the description, like "Array[#]".
             var match = payload.description.match(/\[(\d+)\]$/);
             if (match) {
                 payload.size = parseInt(match[1]);
                 payload.description = payload.description.replace(/\[\d+\]$/, "");
             }
         }

         if (payload.classPrototype)
             payload.classPrototype = WI.RemoteObject.fromPayload(payload.classPrototype, target);

         if (payload.preview) {
             // COMPATIBILITY (iOS 8): Did not have type/subtype/description on
             // Runtime.ObjectPreview. Copy them over from the RemoteObject.
             if (!payload.preview.type) {
                 payload.preview.type = payload.type;
                 payload.preview.subtype = payload.subtype;
                 payload.preview.description = payload.description;
                 payload.preview.size = payload.size;
             }

             payload.preview = WI.ObjectPreview.fromPayload(payload.preview);
         }

         return new WI.RemoteObject(target, payload.objectId, payload.type, payload.subtype, payload.value, payload.description, payload.size, payload.classPrototype, payload.className, payload.preview);
     }

     static createCallArgument(valueOrObject)
     {
         if (valueOrObject instanceof WI.RemoteObject) {
             if (valueOrObject.objectId)
                 return {objectId: valueOrObject.objectId};
             return {value: valueOrObject.value};
         }

         return {value: valueOrObject};
     }

     static resolveNode(node, objectGroup)
     {
         let target = WI.assumingMainTarget();
         return target.DOMAgent.resolveNode(node.id, objectGroup)
             .then(({object}) => WI.RemoteObject.fromPayload(object, WI.mainTarget));
     }

     static resolveWebSocket(webSocketResource, objectGroup, callback)
     {
         console.assert(typeof callback === "function");

         let target = WI.assumingMainTarget();
         target.NetworkAgent.resolveWebSocket(webSocketResource.requestIdentifier, objectGroup, (error, object) => {
             if (error || !object)
                 callback(null);
             else
                 callback(WI.RemoteObject.fromPayload(object, webSocketResource.target));
         });
     }

     static resolveCanvasContext(canvas, objectGroup, callback)
     {
         console.assert(typeof callback === "function");

         function wrapCallback(error, object) {
             if (error || !object)
                 callback(null);
             else
                 callback(WI.RemoteObject.fromPayload(object, WI.mainTarget));
         }

         let target = WI.assumingMainTarget();

         // COMPATIBILITY (iOS 13): Canvas.resolveCanvasContext was renamed to Canvas.resolveContext.
         if (!target.hasCommand("Canvas.resolveContext")) {
             target.CanvasAgent.resolveCanvasContext(canvas.identifier, objectGroup, wrapCallback);
             return;
         }

         target.CanvasAgent.resolveContext(canvas.identifier, objectGroup, wrapCallback);
     }

     // Public

     get target()
     {
         return this._target;
     }

     get objectId()
     {
         return this._objectId;
     }

     get type()
     {
         return this._type;
     }

     get subtype()
     {
         return this._subtype;
     }

     get description()
     {
         return this._description;
     }

     get functionDescription()
     {
         console.assert(this.type === "function");

         return this._functionDescription || this._description;
     }

     get hasChildren()
     {
         return this._hasChildren;
     }

     get value()
     {
         return this._value;
     }

     get size()
     {
         return this._size || 0;
     }

     get classPrototype()
     {
         return this._classPrototype;
     }

     get preview()
     {
         return this._preview;
     }

     hasSize()
     {
         return this.isArray() || this.isCollectionType();
     }

     hasValue()
     {
         return "_value" in this;
     }

     canLoadPreview()
     {
         if (this._failedToLoadPreview)
             return false;

         if (this._type !== "object")
             return false;

         if (!this._objectId || this._isSymbol() || this._isFakeObject())
             return false;

         return true;
     }

     updatePreview(callback)
     {
         if (!this.canLoadPreview()) {
             callback(null);
             return;
         }

         if (!this._target.hasCommand("Runtime.getPreview")) {
             this._failedToLoadPreview = true;
             callback(null);
             return;
         }

         this._target.RuntimeAgent.getPreview(this._objectId, (error, payload) => {
             if (error) {
                 this._failedToLoadPreview = true;
                 callback(null);
                 return;
             }

             this._preview = WI.ObjectPreview.fromPayload(payload);
             callback(this._preview);
         });
     }

     getPropertyDescriptors(callback, options = {})
     {
         if (!this._objectId || this._isSymbol() || this._isFakeObject()) {
             callback([]);
             return;
         }

         this._getProperties(this._getPropertyDescriptorsResolver.bind(this, callback), options);
     }

     getDisplayablePropertyDescriptors(callback, options = {})
     {
         if (!this._objectId || this._isSymbol() || this._isFakeObject()) {
             callback([]);
             return;
         }

         // COMPATIBILITY (iOS 8): Runtime.getDisplayableProperties did not exist.
         // Here we do our best to reimplement it by getting all properties and reducing them down.
         if (!this._target.hasCommand("Runtime.getDisplayableProperties")) {
             this._getProperties(options, (error, allProperties) => {
                 var ownOrGetterPropertiesList = [];
                 if (allProperties) {
                     for (var property of allProperties) {
                         if (property.isOwn || property.name === "__proto__") {
                             // Own property or getter property in prototype chain.
                             ownOrGetterPropertiesList.push(property);
                         } else if (property.value && property.name !== property.name.toUpperCase()) {
                             var type = property.value.type;
                             if (type && type !== "function" && property.name !== "constructor") {
                                 // Possible native binding getter property converted to a value. Also, no CONSTANT name style and not "constructor".
                                 // There is no way of knowing if this is native or not, so just go with it.
                                 ownOrGetterPropertiesList.push(property);
                             }
                         }
                     }
                 }
                 this._getPropertyDescriptorsResolver(callback, error, ownOrGetterPropertiesList);
             });
             return;
         }

         this._getDisplayableProperties(this._getPropertyDescriptorsResolver.bind(this, callback), options);
     }

     setPropertyValue(name, value, callback)
     {
         if (!this._objectId || this._isSymbol() || this._isFakeObject()) {
             callback("Can't set a property of non-object.");
             return;
         }

         // FIXME: It doesn't look like setPropertyValue is used yet. This will need to be tested when it is again (editable ObjectTrees).
         this._target.RuntimeAgent.evaluate.invoke({expression: appendWebInspectorSourceURL(value), doNotPauseOnExceptionsAndMuteConsole: true}, evaluatedCallback.bind(this));

         function evaluatedCallback(error, result, wasThrown)
         {
             if (error || wasThrown) {
                 callback(error || result.description);
                 return;
             }

             function setPropertyValue(propertyName, propertyValue)
             {
                 this[propertyName] = propertyValue;
             }

             delete result.description; // Optimize on traffic.

             this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(setPropertyValue.toString()), [{value: name}, result], true, undefined, propertySetCallback.bind(this));

             if (result._objectId)
                 this._target.RuntimeAgent.releaseObject(result._objectId);
         }

         function propertySetCallback(error, result, wasThrown)
         {
             if (error || wasThrown) {
                 callback(error || result.description);
                 return;
             }

             callback();
         }
     }

     isUndefined()
     {
         return this._type === "undefined";
     }

     isNode()
     {
         return this._subtype === "node";
     }

     isArray()
     {
         return this._subtype === "array";
     }

     isClass()
     {
         return this._subtype === "class";
     }

     isCollectionType()
     {
         return this._subtype === "map" || this._subtype === "set" || this._subtype === "weakmap" || this._subtype === "weakset";
     }

     isWeakCollection()
     {
         return this._subtype === "weakmap" || this._subtype === "weakset";
     }

     getCollectionEntries(callback, {fetchStart, fetchCount} = {})
     {
         console.assert(this.isCollectionType());
         console.assert(typeof fetchStart === "undefined" || (typeof fetchStart === "number" && fetchStart >= 0), fetchStart);
         console.assert(typeof fetchCount === "undefined" || (typeof fetchCount === "number" && fetchCount > 0), fetchCount);

         // WeakMaps and WeakSets are not ordered. We should never send a non-zero start.
         console.assert(!this.isWeakCollection() || typeof fetchStart === "undefined" || fetchStart === 0, fetchStart);

         let objectGroup = this.isWeakCollection() ? this._weakCollectionObjectGroup() : "";

         // COMPATIBILITY (iOS 13): `startIndex` and `numberToFetch` were renamed to `fetchStart` and `fetchCount` (but kept in the same position).
         this._target.RuntimeAgent.getCollectionEntries(this._objectId, objectGroup, fetchStart, fetchCount, (error, entries) => {
             callback(entries.map((x) => WI.CollectionEntry.fromPayload(x, this._target)));
         });
     }

     releaseWeakCollectionEntries()
     {
         console.assert(this.isWeakCollection());

         this._target.RuntimeAgent.releaseObjectGroup(this._weakCollectionObjectGroup());
     }

     pushNodeToFrontend(callback)
     {
         if (this._objectId)
             WI.domManager.pushNodeToFrontend(this._objectId, callback);
         else
             callback(0);
     }

     async fetchProperties(propertyNames, resultObject = {})
     {
         let seenPropertyNames = new Set;
         let requestedValues = [];
         for (let propertyName of propertyNames) {
             // Check this here, otherwise things like '{}' would be valid Set keys.
             if (typeof propertyName !== "string" && typeof propertyName !== "number")
                 throw new Error(`Tried to get property using key is not a string or number: ${propertyName}`);

             if (seenPropertyNames.has(propertyName))
                 continue;

             seenPropertyNames.add(propertyName);
             requestedValues.push(this.getProperty(propertyName));
         }

         // Return primitive values directly, otherwise return a WI.RemoteObject instance.
         function maybeUnwrapValue(remoteObject) {
             return remoteObject.hasValue() ? remoteObject.value : remoteObject;
         }

         // Request property values one by one, since returning an array of property
         // values would then be subject to arbitrary object preview size limits.
         let fetchedKeys = Array.from(seenPropertyNames);
         let fetchedValues = await Promise.all(requestedValues);
         for (let i = 0; i < fetchedKeys.length; ++i)
             resultObject[fetchedKeys[i]] = maybeUnwrapValue(fetchedValues[i]);

         return resultObject;
     }

     getProperty(propertyName, callback = null)
     {
         function inspectedPage_object_getProperty(property) {
             if (typeof property !== "string" && typeof property !== "number")
                 throw new Error(`Tried to get property using key is not a string or number: ${property}`);

             return this[property];
         }

         if (callback && typeof callback === "function")
             this.callFunction(inspectedPage_object_getProperty, [propertyName], true, callback);
         else
             return this.callFunction(inspectedPage_object_getProperty, [propertyName], true);
     }

     callFunction(functionDeclaration, args, generatePreview, callback = null)
     {
         let translateResult = (result) => result ? WI.RemoteObject.fromPayload(result, this._target) : null;

         if (args)
             args = args.map(WI.RemoteObject.createCallArgument);

         if (callback && typeof callback === "function") {
             this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(functionDeclaration.toString()), args, true, undefined, !!generatePreview, (error, result, wasThrown) => {
                 callback(error, translateResult(result), wasThrown);
             });
         } else {
             // Protocol errors and results that were thrown should cause promise rejection with the same.
             return this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(functionDeclaration.toString()), args, true, undefined, !!generatePreview)
                 .then(({result, wasThrown}) => {
                     result = translateResult(result);
                     if (result && wasThrown)
                         return Promise.reject(result);
                     return Promise.resolve(result);
                 });
         }
     }

     callFunctionJSON(functionDeclaration, args, callback)
     {
         function mycallback(error, result, wasThrown)
         {
             callback((error || wasThrown) ? null : result.value);
         }

         this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(functionDeclaration.toString()), args, true, true, mycallback);
     }

     invokeGetter(getterRemoteObject, callback)
     {
         console.assert(getterRemoteObject instanceof WI.RemoteObject);

         function backendInvokeGetter(getter)
         {
             return getter ? getter.call(this) : undefined;
         }

         this.callFunction(backendInvokeGetter, [getterRemoteObject], true, callback);
     }

     getOwnPropertyDescriptor(propertyName, callback)
     {
         function backendGetOwnPropertyDescriptor(propertyName)
         {
             return this[propertyName];
         }

         function wrappedCallback(error, result, wasThrown)
         {
             if (error || wasThrown || !(result instanceof WI.RemoteObject)) {
                 callback(null);
                 return;
             }

             var fakeDescriptor = {name: propertyName, value: result, writable: true, configurable: true};
             var fakePropertyDescriptor = new WI.PropertyDescriptor(fakeDescriptor, null, true, false, false, false);
             callback(fakePropertyDescriptor);
         }

         // FIXME: Implement a real RuntimeAgent.getOwnPropertyDescriptor?
         this.callFunction(backendGetOwnPropertyDescriptor, [propertyName], false, wrappedCallback.bind(this));
     }

     release()
     {
         if (this._objectId && !this._isFakeObject())
             this._target.RuntimeAgent.releaseObject(this._objectId);
     }

     arrayLength()
     {
         if (this._subtype !== "array")
             return 0;

         var matches = this._description.match(/\[([0-9]+)\]/);
         if (!matches)
             return 0;

         return parseInt(matches[1], 10);
     }

     asCallArgument()
     {
         return WI.RemoteObject.createCallArgument(this);
     }

     findFunctionSourceCodeLocation()
     {
         var result = new WI.WrappedPromise;

         if (!this._isFunction() || !this._objectId) {
             result.resolve(WI.RemoteObject.SourceCodeLocationPromise.MissingObjectId);
             return result.promise;
         }

         this._target.DebuggerAgent.getFunctionDetails(this._objectId, (error, response) => {
             if (error) {
                 result.resolve(WI.RemoteObject.SourceCodeLocationPromise.NoSourceFound);
                 return;
             }

             var location = response.location;
             var sourceCode = WI.debuggerManager.scriptForIdentifier(location.scriptId, this._target);

             if (!sourceCode || (!WI.settings.engineeringShowInternalScripts.value && isWebKitInternalScript(sourceCode.sourceURL))) {
                 result.resolve(WI.RemoteObject.SourceCodeLocationPromise.NoSourceFound);
                 return;
             }

             var sourceCodeLocation = sourceCode.createSourceCodeLocation(location.lineNumber, location.columnNumber || 0);
             result.resolve(sourceCodeLocation);
         });

         return result.promise;
     }

     // Private

     _isFakeObject()
     {
         return this._objectId === WI.RemoteObject.FakeRemoteObjectId;
     }

     _isSymbol()
     {
         return this._type === "symbol";
     }

     _isFunction()
     {
         return this._type === "function";
     }

     _weakCollectionObjectGroup()
     {
         return JSON.stringify(this._objectId) + "-" + this._subtype;
     }

     _getProperties(callback, {ownProperties, fetchStart, fetchCount, generatePreview} = {})
     {
         // COMPATIBILITY (iOS 13): `result` was renamed to `properties` (but kept in the same position).
         this._target.RuntimeAgent.getProperties.invoke({
             objectId: this._objectId,
             ownProperties,
             fetchStart,
             fetchCount,
             generatePreview,
         }, callback);
     }

     _getDisplayableProperties(callback, {fetchStart, fetchCount, generatePreview} = {})
     {
         console.assert(this._target.hasCommand("Runtime.getDisplayableProperties"));

         this._target.RuntimeAgent.getDisplayableProperties.invoke({
             objectId: this._objectId,
             fetchStart,
             fetchCount,
             generatePreview,
         }, callback);
     }

     _getPropertyDescriptorsResolver(callback, error, properties, internalProperties)
     {
         if (error) {
             callback(null);
             return;
         }

         let descriptors = properties.map((payload) => WI.PropertyDescriptor.fromPayload(payload, false, this._target));

         if (internalProperties) {
             for (let payload of internalProperties)
                 descriptors.push(WI.PropertyDescriptor.fromPayload(payload, true, this._target));
         }

         callback(descriptors);
     }
 };

 WI.RemoteObject.FakeRemoteObjectId = "fake-remote-object";

 WI.RemoteObject.SourceCodeLocationPromise = {
     NoSourceFound: "remote-object-source-code-location-promise-no-source-found",
     MissingObjectId: "remote-object-source-code-location-promise-missing-object-id"
 };
	/*
	* Copyright (C) 2009 Google Inc. All rights reserved.
	* Copyright (C) 2015 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	WI.RemoteObject = class RemoteObject
	{
	constructor(target, objectId, type, subtype, value, description, size, classPrototype, className, preview)
	{
	console.assert(type);
	console.assert(!preview \|\| preview instanceof WI.ObjectPreview);
	console.assert(!target \|\| target instanceof WI.Target);

	this._target = target \|\| WI.mainTarget;
	this._type = type;
	this._subtype = subtype;

	if (objectId) {
	// Object, Function, or Symbol.
	console.assert(!subtype \|\| typeof subtype === "string");
	console.assert(!description \|\| typeof description === "string");
	console.assert(!value);

	this._objectId = objectId;
	this._description = description \|\| "";
	this._hasChildren = type !== "symbol";
	this._size = size;
	this._classPrototype = classPrototype;
	this._preview = preview;

	if (subtype === "class") {
	this._functionDescription = this._description;
	this._description = "class " + className;
	}
	} else {
	// Primitive, BigInt, or null.
	console.assert(type !== "object" \|\| value === null);
	console.assert(!preview);

	this._description = description \|\| (value + "");
	this._hasChildren = false;
	this._value = value;

	if (type === "bigint") {
	console.assert(value === undefined);
	console.assert(description.endsWith("n"));
	if (window.BigInt)
	this._value = BigInt(description.substring(0, description.length - 1));
	else
	this._value = `${description} [BigInt Not Enabled in Web Inspector]`;
	}
	}
	}

	// Static

	static createFakeRemoteObject()
	{
	return new WI.RemoteObject(undefined, WI.RemoteObject.FakeRemoteObjectId, "object");
	}

	static fromPrimitiveValue(value)
	{
	return new WI.RemoteObject(undefined, undefined, typeof value, undefined, value, undefined, undefined, undefined, undefined);
	}

	static createBigIntFromDescriptionString(description)
	{
	console.assert(description.endsWith("n"));

	return new WI.RemoteObject(undefined, undefined, "bigint", undefined, undefined, description, undefined, undefined, undefined);
	}

	static fromPayload(payload, target)
	{
	console.assert(typeof payload === "object", "Remote object payload should only be an object");

	if (payload.subtype === "array") {
	// COMPATIBILITY (iOS 8): Runtime.RemoteObject did not have size property,
	// instead it was tacked onto the end of the description, like "Array[#]".
	var match = payload.description.match(/\[(\d+)\]$/);
	if (match) {
	payload.size = parseInt(match[1]);
	payload.description = payload.description.replace(/\[\d+\]$/, "");
	}
	}

	if (payload.classPrototype)
	payload.classPrototype = WI.RemoteObject.fromPayload(payload.classPrototype, target);

	if (payload.preview) {
	// COMPATIBILITY (iOS 8): Did not have type/subtype/description on
	// Runtime.ObjectPreview. Copy them over from the RemoteObject.
	if (!payload.preview.type) {
	payload.preview.type = payload.type;
	payload.preview.subtype = payload.subtype;
	payload.preview.description = payload.description;
	payload.preview.size = payload.size;
	}

	payload.preview = WI.ObjectPreview.fromPayload(payload.preview);
	}

	return new WI.RemoteObject(target, payload.objectId, payload.type, payload.subtype, payload.value, payload.description, payload.size, payload.classPrototype, payload.className, payload.preview);
	}

	static createCallArgument(valueOrObject)
	{
	if (valueOrObject instanceof WI.RemoteObject) {
	if (valueOrObject.objectId)
	return {objectId: valueOrObject.objectId};
	return {value: valueOrObject.value};
	}

	return {value: valueOrObject};
	}

	static resolveNode(node, objectGroup)
	{
	let target = WI.assumingMainTarget();
	return target.DOMAgent.resolveNode(node.id, objectGroup)
	.then(({object}) => WI.RemoteObject.fromPayload(object, WI.mainTarget));
	}

	static resolveWebSocket(webSocketResource, objectGroup, callback)
	{
	console.assert(typeof callback === "function");

	let target = WI.assumingMainTarget();
	target.NetworkAgent.resolveWebSocket(webSocketResource.requestIdentifier, objectGroup, (error, object) => {
	if (error \|\| !object)
	callback(null);
	else
	callback(WI.RemoteObject.fromPayload(object, webSocketResource.target));
	});
	}

	static resolveCanvasContext(canvas, objectGroup, callback)
	{
	console.assert(typeof callback === "function");

	function wrapCallback(error, object) {
	if (error \|\| !object)
	callback(null);
	else
	callback(WI.RemoteObject.fromPayload(object, WI.mainTarget));
	}

	let target = WI.assumingMainTarget();

	// COMPATIBILITY (iOS 13): Canvas.resolveCanvasContext was renamed to Canvas.resolveContext.
	if (!target.hasCommand("Canvas.resolveContext")) {
	target.CanvasAgent.resolveCanvasContext(canvas.identifier, objectGroup, wrapCallback);
	return;
	}

	target.CanvasAgent.resolveContext(canvas.identifier, objectGroup, wrapCallback);
	}

	// Public

	get target()
	{
	return this._target;
	}

	get objectId()
	{
	return this._objectId;
	}

	get type()
	{
	return this._type;
	}

	get subtype()
	{
	return this._subtype;
	}

	get description()
	{
	return this._description;
	}

	get functionDescription()
	{
	console.assert(this.type === "function");

	return this._functionDescription \|\| this._description;
	}

	get hasChildren()
	{
	return this._hasChildren;
	}

	get value()
	{
	return this._value;
	}

	get size()
	{
	return this._size \|\| 0;
	}

	get classPrototype()
	{
	return this._classPrototype;
	}

	get preview()
	{
	return this._preview;
	}

	hasSize()
	{
	return this.isArray() \|\| this.isCollectionType();
	}

	hasValue()
	{
	return "_value" in this;
	}

	canLoadPreview()
	{
	if (this._failedToLoadPreview)
	return false;

	if (this._type !== "object")
	return false;

	if (!this._objectId \|\| this._isSymbol() \|\| this._isFakeObject())
	return false;

	return true;
	}

	updatePreview(callback)
	{
	if (!this.canLoadPreview()) {
	callback(null);
	return;
	}

	if (!this._target.hasCommand("Runtime.getPreview")) {
	this._failedToLoadPreview = true;
	callback(null);
	return;
	}

	this._target.RuntimeAgent.getPreview(this._objectId, (error, payload) => {
	if (error) {
	this._failedToLoadPreview = true;
	callback(null);
	return;
	}

	this._preview = WI.ObjectPreview.fromPayload(payload);
	callback(this._preview);
	});
	}

	getPropertyDescriptors(callback, options = {})
	{
	if (!this._objectId \|\| this._isSymbol() \|\| this._isFakeObject()) {
	callback([]);
	return;
	}

	this._getProperties(this._getPropertyDescriptorsResolver.bind(this, callback), options);
	}

	getDisplayablePropertyDescriptors(callback, options = {})
	{
	if (!this._objectId \|\| this._isSymbol() \|\| this._isFakeObject()) {
	callback([]);
	return;
	}

	// COMPATIBILITY (iOS 8): Runtime.getDisplayableProperties did not exist.
	// Here we do our best to reimplement it by getting all properties and reducing them down.
	if (!this._target.hasCommand("Runtime.getDisplayableProperties")) {
	this._getProperties(options, (error, allProperties) => {
	var ownOrGetterPropertiesList = [];
	if (allProperties) {
	for (var property of allProperties) {
	if (property.isOwn \|\| property.name === "__proto__") {
	// Own property or getter property in prototype chain.
	ownOrGetterPropertiesList.push(property);
	} else if (property.value && property.name !== property.name.toUpperCase()) {
	var type = property.value.type;
	if (type && type !== "function" && property.name !== "constructor") {
	// Possible native binding getter property converted to a value. Also, no CONSTANT name style and not "constructor".
	// There is no way of knowing if this is native or not, so just go with it.
	ownOrGetterPropertiesList.push(property);
	}
	}
	}
	}
	this._getPropertyDescriptorsResolver(callback, error, ownOrGetterPropertiesList);
	});
	return;
	}

	this._getDisplayableProperties(this._getPropertyDescriptorsResolver.bind(this, callback), options);
	}

	setPropertyValue(name, value, callback)
	{
	if (!this._objectId \|\| this._isSymbol() \|\| this._isFakeObject()) {
	callback("Can't set a property of non-object.");
	return;
	}

	// FIXME: It doesn't look like setPropertyValue is used yet. This will need to be tested when it is again (editable ObjectTrees).
	this._target.RuntimeAgent.evaluate.invoke({expression: appendWebInspectorSourceURL(value), doNotPauseOnExceptionsAndMuteConsole: true}, evaluatedCallback.bind(this));

	function evaluatedCallback(error, result, wasThrown)
	{
	if (error \|\| wasThrown) {
	callback(error \|\| result.description);
	return;
	}

	function setPropertyValue(propertyName, propertyValue)
	{
	this[propertyName] = propertyValue;
	}

	delete result.description; // Optimize on traffic.

	this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(setPropertyValue.toString()), [{value: name}, result], true, undefined, propertySetCallback.bind(this));

	if (result._objectId)
	this._target.RuntimeAgent.releaseObject(result._objectId);
	}

	function propertySetCallback(error, result, wasThrown)
	{
	if (error \|\| wasThrown) {
	callback(error \|\| result.description);
	return;
	}

	callback();
	}
	}

	isUndefined()
	{
	return this._type === "undefined";
	}

	isNode()
	{
	return this._subtype === "node";
	}

	isArray()
	{
	return this._subtype === "array";
	}

	isClass()
	{
	return this._subtype === "class";
	}

	isCollectionType()
	{
	return this._subtype === "map" \|\| this._subtype === "set" \|\| this._subtype === "weakmap" \|\| this._subtype === "weakset";
	}

	isWeakCollection()
	{
	return this._subtype === "weakmap" \|\| this._subtype === "weakset";
	}

	getCollectionEntries(callback, {fetchStart, fetchCount} = {})
	{
	console.assert(this.isCollectionType());
	console.assert(typeof fetchStart === "undefined" \|\| (typeof fetchStart === "number" && fetchStart >= 0), fetchStart);
	console.assert(typeof fetchCount === "undefined" \|\| (typeof fetchCount === "number" && fetchCount > 0), fetchCount);

	// WeakMaps and WeakSets are not ordered. We should never send a non-zero start.
	console.assert(!this.isWeakCollection() \|\| typeof fetchStart === "undefined" \|\| fetchStart === 0, fetchStart);

	let objectGroup = this.isWeakCollection() ? this._weakCollectionObjectGroup() : "";

	// COMPATIBILITY (iOS 13): `startIndex` and `numberToFetch` were renamed to `fetchStart` and `fetchCount` (but kept in the same position).
	this._target.RuntimeAgent.getCollectionEntries(this._objectId, objectGroup, fetchStart, fetchCount, (error, entries) => {
	callback(entries.map((x) => WI.CollectionEntry.fromPayload(x, this._target)));
	});
	}

	releaseWeakCollectionEntries()
	{
	console.assert(this.isWeakCollection());

	this._target.RuntimeAgent.releaseObjectGroup(this._weakCollectionObjectGroup());
	}

	pushNodeToFrontend(callback)
	{
	if (this._objectId)
	WI.domManager.pushNodeToFrontend(this._objectId, callback);
	else
	callback(0);
	}

	async fetchProperties(propertyNames, resultObject = {})
	{
	let seenPropertyNames = new Set;
	let requestedValues = [];
	for (let propertyName of propertyNames) {
	// Check this here, otherwise things like '{}' would be valid Set keys.
	if (typeof propertyName !== "string" && typeof propertyName !== "number")
	throw new Error(`Tried to get property using key is not a string or number: ${propertyName}`);

	if (seenPropertyNames.has(propertyName))
	continue;

	seenPropertyNames.add(propertyName);
	requestedValues.push(this.getProperty(propertyName));
	}

	// Return primitive values directly, otherwise return a WI.RemoteObject instance.
	function maybeUnwrapValue(remoteObject) {
	return remoteObject.hasValue() ? remoteObject.value : remoteObject;
	}

	// Request property values one by one, since returning an array of property
	// values would then be subject to arbitrary object preview size limits.
	let fetchedKeys = Array.from(seenPropertyNames);
	let fetchedValues = await Promise.all(requestedValues);
	for (let i = 0; i < fetchedKeys.length; ++i)
	resultObject[fetchedKeys[i]] = maybeUnwrapValue(fetchedValues[i]);

	return resultObject;
	}

	getProperty(propertyName, callback = null)
	{
	function inspectedPage_object_getProperty(property) {
	if (typeof property !== "string" && typeof property !== "number")
	throw new Error(`Tried to get property using key is not a string or number: ${property}`);

	return this[property];
	}

	if (callback && typeof callback === "function")
	this.callFunction(inspectedPage_object_getProperty, [propertyName], true, callback);
	else
	return this.callFunction(inspectedPage_object_getProperty, [propertyName], true);
	}

	callFunction(functionDeclaration, args, generatePreview, callback = null)
	{
	let translateResult = (result) => result ? WI.RemoteObject.fromPayload(result, this._target) : null;

	if (args)
	args = args.map(WI.RemoteObject.createCallArgument);

	if (callback && typeof callback === "function") {
	this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(functionDeclaration.toString()), args, true, undefined, !!generatePreview, (error, result, wasThrown) => {
	callback(error, translateResult(result), wasThrown);
	});
	} else {
	// Protocol errors and results that were thrown should cause promise rejection with the same.
	return this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(functionDeclaration.toString()), args, true, undefined, !!generatePreview)
	.then(({result, wasThrown}) => {
	result = translateResult(result);
	if (result && wasThrown)
	return Promise.reject(result);
	return Promise.resolve(result);
	});
	}
	}

	callFunctionJSON(functionDeclaration, args, callback)
	{
	function mycallback(error, result, wasThrown)
	{
	callback((error \|\| wasThrown) ? null : result.value);
	}

	this._target.RuntimeAgent.callFunctionOn(this._objectId, appendWebInspectorSourceURL(functionDeclaration.toString()), args, true, true, mycallback);
	}

	invokeGetter(getterRemoteObject, callback)
	{
	console.assert(getterRemoteObject instanceof WI.RemoteObject);

	function backendInvokeGetter(getter)
	{
	return getter ? getter.call(this) : undefined;
	}

	this.callFunction(backendInvokeGetter, [getterRemoteObject], true, callback);
	}

	getOwnPropertyDescriptor(propertyName, callback)
	{
	function backendGetOwnPropertyDescriptor(propertyName)
	{
	return this[propertyName];
	}

	function wrappedCallback(error, result, wasThrown)
	{
	if (error \|\| wasThrown \|\| !(result instanceof WI.RemoteObject)) {
	callback(null);
	return;
	}

	var fakeDescriptor = {name: propertyName, value: result, writable: true, configurable: true};
	var fakePropertyDescriptor = new WI.PropertyDescriptor(fakeDescriptor, null, true, false, false, false);
	callback(fakePropertyDescriptor);
	}

	// FIXME: Implement a real RuntimeAgent.getOwnPropertyDescriptor?
	this.callFunction(backendGetOwnPropertyDescriptor, [propertyName], false, wrappedCallback.bind(this));
	}

	release()
	{
	if (this._objectId && !this._isFakeObject())
	this._target.RuntimeAgent.releaseObject(this._objectId);
	}

	arrayLength()
	{
	if (this._subtype !== "array")
	return 0;

	var matches = this._description.match(/\[([0-9]+)\]/);
	if (!matches)
	return 0;

	return parseInt(matches[1], 10);
	}

	asCallArgument()
	{
	return WI.RemoteObject.createCallArgument(this);
	}

	findFunctionSourceCodeLocation()
	{
	var result = new WI.WrappedPromise;

	if (!this._isFunction() \|\| !this._objectId) {
	result.resolve(WI.RemoteObject.SourceCodeLocationPromise.MissingObjectId);
	return result.promise;
	}

	this._target.DebuggerAgent.getFunctionDetails(this._objectId, (error, response) => {
	if (error) {
	result.resolve(WI.RemoteObject.SourceCodeLocationPromise.NoSourceFound);
	return;
	}

	var location = response.location;
	var sourceCode = WI.debuggerManager.scriptForIdentifier(location.scriptId, this._target);

	if (!sourceCode \|\| (!WI.settings.engineeringShowInternalScripts.value && isWebKitInternalScript(sourceCode.sourceURL))) {
	result.resolve(WI.RemoteObject.SourceCodeLocationPromise.NoSourceFound);
	return;
	}

	var sourceCodeLocation = sourceCode.createSourceCodeLocation(location.lineNumber, location.columnNumber \|\| 0);
	result.resolve(sourceCodeLocation);
	});

	return result.promise;
	}

	// Private

	_isFakeObject()
	{
	return this._objectId === WI.RemoteObject.FakeRemoteObjectId;
	}

	_isSymbol()
	{
	return this._type === "symbol";
	}

	_isFunction()
	{
	return this._type === "function";
	}

	_weakCollectionObjectGroup()
	{
	return JSON.stringify(this._objectId) + "-" + this._subtype;
	}

	_getProperties(callback, {ownProperties, fetchStart, fetchCount, generatePreview} = {})
	{
	// COMPATIBILITY (iOS 13): `result` was renamed to `properties` (but kept in the same position).
	this._target.RuntimeAgent.getProperties.invoke({
	objectId: this._objectId,
	ownProperties,
	fetchStart,
	fetchCount,
	generatePreview,
	}, callback);
	}

	_getDisplayableProperties(callback, {fetchStart, fetchCount, generatePreview} = {})
	{
	console.assert(this._target.hasCommand("Runtime.getDisplayableProperties"));

	this._target.RuntimeAgent.getDisplayableProperties.invoke({
	objectId: this._objectId,
	fetchStart,
	fetchCount,
	generatePreview,
	}, callback);
	}

	_getPropertyDescriptorsResolver(callback, error, properties, internalProperties)
	{
	if (error) {
	callback(null);
	return;
	}

	let descriptors = properties.map((payload) => WI.PropertyDescriptor.fromPayload(payload, false, this._target));

	if (internalProperties) {
	for (let payload of internalProperties)
	descriptors.push(WI.PropertyDescriptor.fromPayload(payload, true, this._target));
	}

	callback(descriptors);
	}
	};

	WI.RemoteObject.FakeRemoteObjectId = "fake-remote-object";

	WI.RemoteObject.SourceCodeLocationPromise = {
	NoSourceFound: "remote-object-source-code-location-promise-no-source-found",
	MissingObjectId: "remote-object-source-code-location-promise-missing-object-id"
	};