Source/JavaScriptCore/inspector/InspectorBackendDispatcher.cpp - third_party/webkit - Git at Google

 /*
  * Copyright (C) 2013, 2015 Apple Inc. All Rights Reserved.
  * Copyright (C) 2011 The Chromium Authors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
  */

 #include "config.h"
 #include "InspectorBackendDispatcher.h"

 #include "InspectorFrontendRouter.h"
 #include "InspectorValues.h"
 #include <wtf/TemporaryChange.h>
 #include <wtf/text/CString.h>
 #include <wtf/text/WTFString.h>

 namespace Inspector {

 SupplementalBackendDispatcher::SupplementalBackendDispatcher(BackendDispatcher& backendDispatcher)
     : m_backendDispatcher(backendDispatcher)
 {
 }

 SupplementalBackendDispatcher::~SupplementalBackendDispatcher()
 {
 }

 BackendDispatcher::CallbackBase::CallbackBase(Ref<BackendDispatcher>&& backendDispatcher, long requestId)
     : m_backendDispatcher(WTFMove(backendDispatcher))
     , m_requestId(requestId)
 {
 }

 bool BackendDispatcher::CallbackBase::isActive() const
 {
     return !m_alreadySent && m_backendDispatcher->isActive();
 }

 void BackendDispatcher::CallbackBase::sendFailure(const ErrorString& error)
 {
     ASSERT(error.length());

     if (m_alreadySent)
         return;

     m_alreadySent = true;

     // Immediately send an error message since this is an async response with a single error.
     m_backendDispatcher->reportProtocolError(m_requestId, ServerError, error);
     m_backendDispatcher->sendPendingErrors();
 }

 void BackendDispatcher::CallbackBase::sendSuccess(RefPtr<InspectorObject>&& partialMessage)
 {
     if (m_alreadySent)
         return;

     m_alreadySent = true;
     m_backendDispatcher->sendResponse(m_requestId, WTFMove(partialMessage));
 }

 BackendDispatcher::BackendDispatcher(Ref<FrontendRouter>&& router)
     : m_frontendRouter(WTFMove(router))
 {
 }

 Ref<BackendDispatcher> BackendDispatcher::create(Ref<FrontendRouter>&& router)
 {
     return adoptRef(*new BackendDispatcher(WTFMove(router)));
 }

 bool BackendDispatcher::isActive() const
 {
     return m_frontendRouter->hasFrontends();
 }

 void BackendDispatcher::registerDispatcherForDomain(const String& domain, SupplementalBackendDispatcher* dispatcher)
 {
     ASSERT_ARG(dispatcher, dispatcher);

     // FIXME: <https://webkit.org/b/148492> Agents should only register with the backend once,
     // and we should re-add the assertion that only one dispatcher is registered per domain.
     m_dispatchers.set(domain, dispatcher);
 }

 void BackendDispatcher::dispatch(const String& message)
 {
     Ref<BackendDispatcher> protect(*this);

     ASSERT(!m_protocolErrors.size());

     long requestId = 0;
     RefPtr<InspectorObject> messageObject;

     {
         // In case this is a re-entrant call from a nested run loop, we don't want to lose
         // the outer request's id just because the inner request is bogus.
         TemporaryChange<Optional<long>> scopedRequestId(m_currentRequestId, Nullopt);

         RefPtr<InspectorValue> parsedMessage;
         if (!InspectorValue::parseJSON(message, parsedMessage)) {
             reportProtocolError(ParseError, ASCIILiteral("Message must be in JSON format"));
             sendPendingErrors();
             return;
         }

         if (!parsedMessage->asObject(messageObject)) {
             reportProtocolError(InvalidRequest, ASCIILiteral("Message must be a JSONified object"));
             sendPendingErrors();
             return;
         }

         RefPtr<InspectorValue> requestIdValue;
         if (!messageObject->getValue(ASCIILiteral("id"), requestIdValue)) {
             reportProtocolError(InvalidRequest, ASCIILiteral("'id' property was not found"));
             sendPendingErrors();
             return;
         }

         if (!requestIdValue->asInteger(requestId)) {
             reportProtocolError(InvalidRequest, ASCIILiteral("The type of 'id' property must be integer"));
             sendPendingErrors();
             return;
         }
     }

     {
         // We could be called re-entrantly from a nested run loop, so restore the previous id.
         TemporaryChange<Optional<long>> scopedRequestId(m_currentRequestId, requestId);

         RefPtr<InspectorValue> methodValue;
         if (!messageObject->getValue(ASCIILiteral("method"), methodValue)) {
             reportProtocolError(InvalidRequest, ASCIILiteral("'method' property wasn't found"));
             sendPendingErrors();
             return;
         }

         String methodString;
         if (!methodValue->asString(methodString)) {
             reportProtocolError(InvalidRequest, ASCIILiteral("The type of 'method' property must be string"));
             sendPendingErrors();
             return;
         }

         Vector<String> domainAndMethod;
         methodString.split('.', true, domainAndMethod);
         if (domainAndMethod.size() != 2 || !domainAndMethod[0].length() || !domainAndMethod[1].length()) {
             reportProtocolError(InvalidRequest, ASCIILiteral("The 'method' property was formatted incorrectly. It should be 'Domain.method'"));
             sendPendingErrors();
             return;
         }

         String domain = domainAndMethod[0];
         SupplementalBackendDispatcher* domainDispatcher = m_dispatchers.get(domain);
         if (!domainDispatcher) {
             reportProtocolError(MethodNotFound, "'" + domain + "' domain was not found");
             sendPendingErrors();
             return;
         }

         String method = domainAndMethod[1];
         domainDispatcher->dispatch(requestId, method, messageObject.releaseNonNull());

         if (m_protocolErrors.size())
             sendPendingErrors();
     }
 }

 void BackendDispatcher::sendResponse(long requestId, RefPtr<InspectorObject>&& result)
 {
     ASSERT(!m_protocolErrors.size());

     // The JSON-RPC 2.0 specification requires that the "error" member have the value 'null'
     // if no error occurred during an invocation, but we do not include it at all.
     Ref<InspectorObject> responseMessage = InspectorObject::create();
     responseMessage->setObject(ASCIILiteral("result"), WTFMove(result));
     responseMessage->setInteger(ASCIILiteral("id"), requestId);
     m_frontendRouter->sendResponse(responseMessage->toJSONString());
 }

 void BackendDispatcher::sendPendingErrors()
 {
     // These error codes are specified in JSON-RPC 2.0, Section 5.1.
     static const int errorCodes[] = {
         -32700, // ParseError
         -32600, // InvalidRequest
         -32601, // MethodNotFound
         -32602, // InvalidParams
         -32603, // InternalError
         -32000, // ServerError
     };

     // To construct the error object, only use the last error's code and message.
     // Per JSON-RPC 2.0, Section 5.1, the 'data' member may contain nested errors,
     // but only one top-level Error object should be sent per request.
     CommonErrorCode errorCode = InternalError;
     String errorMessage;
     Ref<InspectorArray> payload = InspectorArray::create();

     for (auto& data : m_protocolErrors) {
         errorCode = std::get<0>(data);
         errorMessage = std::get<1>(data);

         ASSERT_ARG(errorCode, (unsigned)errorCode < WTF_ARRAY_LENGTH(errorCodes));
         ASSERT_ARG(errorCode, errorCodes[errorCode]);

         Ref<InspectorObject> error = InspectorObject::create();
         error->setInteger(ASCIILiteral("code"), errorCodes[errorCode]);
         error->setString(ASCIILiteral("message"), errorMessage);
         payload->pushObject(WTFMove(error));
     }

     Ref<InspectorObject> topLevelError = InspectorObject::create();
     topLevelError->setInteger(ASCIILiteral("code"), errorCodes[errorCode]);
     topLevelError->setString(ASCIILiteral("message"), errorMessage);
     topLevelError->setArray(ASCIILiteral("data"), WTFMove(payload));

     Ref<InspectorObject> message = InspectorObject::create();
     message->setObject(ASCIILiteral("error"), WTFMove(topLevelError));
     if (m_currentRequestId)
         message->setInteger(ASCIILiteral("id"), m_currentRequestId.value());
     else {
         // The 'null' value for an unknown id is specified in JSON-RPC 2.0, Section 5.
         message->setValue(ASCIILiteral("id"), InspectorValue::null());
     }

     m_frontendRouter->sendResponse(message->toJSONString());

     m_protocolErrors.clear();
     m_currentRequestId = Nullopt;
 }

 void BackendDispatcher::reportProtocolError(CommonErrorCode errorCode, const String& errorMessage)
 {
     reportProtocolError(m_currentRequestId, errorCode, errorMessage);
 }

 void BackendDispatcher::reportProtocolError(Optional<long> relatedRequestId, CommonErrorCode errorCode, const String& errorMessage)
 {
     ASSERT_ARG(errorCode, errorCode >= 0);

     // If the error was reported from an async callback, then no request id will be registered yet.
     if (!m_currentRequestId)
         m_currentRequestId = relatedRequestId;

     m_protocolErrors.append(std::tuple<CommonErrorCode, String>(errorCode, errorMessage));
 }

 template<typename T>
 T BackendDispatcher::getPropertyValue(InspectorObject* object, const String& name, bool* out_optionalValueFound, T defaultValue, std::function<bool(InspectorValue&, T&)> asMethod, const char* typeName)
 {
     T result(defaultValue);
     // out_optionalValueFound signals to the caller whether an optional property was found.
     // if out_optionalValueFound == nullptr, then this is a required property.
     if (out_optionalValueFound)
         *out_optionalValueFound = false;

     if (!object) {
         if (!out_optionalValueFound)
             reportProtocolError(BackendDispatcher::InvalidParams, String::format("'params' object must contain required parameter '%s' with type '%s'.", name.utf8().data(), typeName));
         return result;
     }

     auto findResult = object->find(name);
     if (findResult == object->end()) {
         if (!out_optionalValueFound)
             reportProtocolError(BackendDispatcher::InvalidParams, String::format("Parameter '%s' with type '%s' was not found.", name.utf8().data(), typeName));
         return result;
     }

     if (!asMethod(*findResult->value, result)) {
         reportProtocolError(BackendDispatcher::InvalidParams, String::format("Parameter '%s' has wrong type. It must be '%s'.", name.utf8().data(), typeName));
         return result;
     }

     if (out_optionalValueFound)
         *out_optionalValueFound = true;

     return result;
 }

 static bool castToInteger(InspectorValue& value, int& result) { return value.asInteger(result); }
 static bool castToNumber(InspectorValue& value, double& result) { return value.asDouble(result); }

 int BackendDispatcher::getInteger(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<int>(object, name, valueFound, 0, &castToInteger, "Integer");
 }

 double BackendDispatcher::getDouble(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<double>(object, name, valueFound, 0, &castToNumber, "Number");
 }

 String BackendDispatcher::getString(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<String>(object, name, valueFound, "", &InspectorValue::asString, "String");
 }

 bool BackendDispatcher::getBoolean(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<bool>(object, name, valueFound, false, &InspectorValue::asBoolean, "Boolean");
 }

 RefPtr<InspectorObject> BackendDispatcher::getObject(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<RefPtr<InspectorObject>>(object, name, valueFound, nullptr, &InspectorValue::asObject, "Object");
 }

 RefPtr<InspectorArray> BackendDispatcher::getArray(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<RefPtr<InspectorArray>>(object, name, valueFound, nullptr, &InspectorValue::asArray, "Array");
 }

 RefPtr<InspectorValue> BackendDispatcher::getValue(InspectorObject* object, const String& name, bool* valueFound)
 {
     return getPropertyValue<RefPtr<InspectorValue>>(object, name, valueFound, nullptr, &InspectorValue::asValue, "Value");
 }

 } // namespace Inspector
	/*
	* Copyright (C) 2013, 2015 Apple Inc. All Rights Reserved.
	* Copyright (C) 2011 The Chromium Authors. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. 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.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
	*/

	#include "config.h"
	#include "InspectorBackendDispatcher.h"

	#include "InspectorFrontendRouter.h"
	#include "InspectorValues.h"
	#include <wtf/TemporaryChange.h>
	#include <wtf/text/CString.h>
	#include <wtf/text/WTFString.h>

	namespace Inspector {

	SupplementalBackendDispatcher::SupplementalBackendDispatcher(BackendDispatcher& backendDispatcher)
	: m_backendDispatcher(backendDispatcher)
	{
	}

	SupplementalBackendDispatcher::~SupplementalBackendDispatcher()
	{
	}

	BackendDispatcher::CallbackBase::CallbackBase(Ref<BackendDispatcher>&& backendDispatcher, long requestId)
	: m_backendDispatcher(WTFMove(backendDispatcher))
	, m_requestId(requestId)
	{
	}

	bool BackendDispatcher::CallbackBase::isActive() const
	{
	return !m_alreadySent && m_backendDispatcher->isActive();
	}

	void BackendDispatcher::CallbackBase::sendFailure(const ErrorString& error)
	{
	ASSERT(error.length());

	if (m_alreadySent)
	return;

	m_alreadySent = true;

	// Immediately send an error message since this is an async response with a single error.
	m_backendDispatcher->reportProtocolError(m_requestId, ServerError, error);
	m_backendDispatcher->sendPendingErrors();
	}

	void BackendDispatcher::CallbackBase::sendSuccess(RefPtr<InspectorObject>&& partialMessage)
	{
	if (m_alreadySent)
	return;

	m_alreadySent = true;
	m_backendDispatcher->sendResponse(m_requestId, WTFMove(partialMessage));
	}

	BackendDispatcher::BackendDispatcher(Ref<FrontendRouter>&& router)
	: m_frontendRouter(WTFMove(router))
	{
	}

	Ref<BackendDispatcher> BackendDispatcher::create(Ref<FrontendRouter>&& router)
	{
	return adoptRef(*new BackendDispatcher(WTFMove(router)));
	}

	bool BackendDispatcher::isActive() const
	{
	return m_frontendRouter->hasFrontends();
	}

	void BackendDispatcher::registerDispatcherForDomain(const String& domain, SupplementalBackendDispatcher* dispatcher)
	{
	ASSERT_ARG(dispatcher, dispatcher);

	// FIXME: <https://webkit.org/b/148492> Agents should only register with the backend once,
	// and we should re-add the assertion that only one dispatcher is registered per domain.
	m_dispatchers.set(domain, dispatcher);
	}

	void BackendDispatcher::dispatch(const String& message)
	{
	Ref<BackendDispatcher> protect(*this);

	ASSERT(!m_protocolErrors.size());

	long requestId = 0;
	RefPtr<InspectorObject> messageObject;

	{
	// In case this is a re-entrant call from a nested run loop, we don't want to lose
	// the outer request's id just because the inner request is bogus.
	TemporaryChange<Optional<long>> scopedRequestId(m_currentRequestId, Nullopt);

	RefPtr<InspectorValue> parsedMessage;
	if (!InspectorValue::parseJSON(message, parsedMessage)) {
	reportProtocolError(ParseError, ASCIILiteral("Message must be in JSON format"));
	sendPendingErrors();
	return;
	}

	if (!parsedMessage->asObject(messageObject)) {
	reportProtocolError(InvalidRequest, ASCIILiteral("Message must be a JSONified object"));
	sendPendingErrors();
	return;
	}

	RefPtr<InspectorValue> requestIdValue;
	if (!messageObject->getValue(ASCIILiteral("id"), requestIdValue)) {
	reportProtocolError(InvalidRequest, ASCIILiteral("'id' property was not found"));
	sendPendingErrors();
	return;
	}

	if (!requestIdValue->asInteger(requestId)) {
	reportProtocolError(InvalidRequest, ASCIILiteral("The type of 'id' property must be integer"));
	sendPendingErrors();
	return;
	}
	}

	{
	// We could be called re-entrantly from a nested run loop, so restore the previous id.
	TemporaryChange<Optional<long>> scopedRequestId(m_currentRequestId, requestId);

	RefPtr<InspectorValue> methodValue;
	if (!messageObject->getValue(ASCIILiteral("method"), methodValue)) {
	reportProtocolError(InvalidRequest, ASCIILiteral("'method' property wasn't found"));
	sendPendingErrors();
	return;
	}

	String methodString;
	if (!methodValue->asString(methodString)) {
	reportProtocolError(InvalidRequest, ASCIILiteral("The type of 'method' property must be string"));
	sendPendingErrors();
	return;
	}

	Vector<String> domainAndMethod;
	methodString.split('.', true, domainAndMethod);
	if (domainAndMethod.size() != 2 \|\| !domainAndMethod[0].length() \|\| !domainAndMethod[1].length()) {
	reportProtocolError(InvalidRequest, ASCIILiteral("The 'method' property was formatted incorrectly. It should be 'Domain.method'"));
	sendPendingErrors();
	return;
	}

	String domain = domainAndMethod[0];
	SupplementalBackendDispatcher* domainDispatcher = m_dispatchers.get(domain);
	if (!domainDispatcher) {
	reportProtocolError(MethodNotFound, "'" + domain + "' domain was not found");
	sendPendingErrors();
	return;
	}

	String method = domainAndMethod[1];
	domainDispatcher->dispatch(requestId, method, messageObject.releaseNonNull());

	if (m_protocolErrors.size())
	sendPendingErrors();
	}
	}

	void BackendDispatcher::sendResponse(long requestId, RefPtr<InspectorObject>&& result)
	{
	ASSERT(!m_protocolErrors.size());

	// The JSON-RPC 2.0 specification requires that the "error" member have the value 'null'
	// if no error occurred during an invocation, but we do not include it at all.
	Ref<InspectorObject> responseMessage = InspectorObject::create();
	responseMessage->setObject(ASCIILiteral("result"), WTFMove(result));
	responseMessage->setInteger(ASCIILiteral("id"), requestId);
	m_frontendRouter->sendResponse(responseMessage->toJSONString());
	}

	void BackendDispatcher::sendPendingErrors()
	{
	// These error codes are specified in JSON-RPC 2.0, Section 5.1.
	static const int errorCodes[] = {
	-32700, // ParseError
	-32600, // InvalidRequest
	-32601, // MethodNotFound
	-32602, // InvalidParams
	-32603, // InternalError
	-32000, // ServerError
	};

	// To construct the error object, only use the last error's code and message.
	// Per JSON-RPC 2.0, Section 5.1, the 'data' member may contain nested errors,
	// but only one top-level Error object should be sent per request.
	CommonErrorCode errorCode = InternalError;
	String errorMessage;
	Ref<InspectorArray> payload = InspectorArray::create();

	for (auto& data : m_protocolErrors) {
	errorCode = std::get<0>(data);
	errorMessage = std::get<1>(data);

	ASSERT_ARG(errorCode, (unsigned)errorCode < WTF_ARRAY_LENGTH(errorCodes));
	ASSERT_ARG(errorCode, errorCodes[errorCode]);

	Ref<InspectorObject> error = InspectorObject::create();
	error->setInteger(ASCIILiteral("code"), errorCodes[errorCode]);
	error->setString(ASCIILiteral("message"), errorMessage);
	payload->pushObject(WTFMove(error));
	}

	Ref<InspectorObject> topLevelError = InspectorObject::create();
	topLevelError->setInteger(ASCIILiteral("code"), errorCodes[errorCode]);
	topLevelError->setString(ASCIILiteral("message"), errorMessage);
	topLevelError->setArray(ASCIILiteral("data"), WTFMove(payload));

	Ref<InspectorObject> message = InspectorObject::create();
	message->setObject(ASCIILiteral("error"), WTFMove(topLevelError));
	if (m_currentRequestId)
	message->setInteger(ASCIILiteral("id"), m_currentRequestId.value());
	else {
	// The 'null' value for an unknown id is specified in JSON-RPC 2.0, Section 5.
	message->setValue(ASCIILiteral("id"), InspectorValue::null());
	}

	m_frontendRouter->sendResponse(message->toJSONString());

	m_protocolErrors.clear();
	m_currentRequestId = Nullopt;
	}

	void BackendDispatcher::reportProtocolError(CommonErrorCode errorCode, const String& errorMessage)
	{
	reportProtocolError(m_currentRequestId, errorCode, errorMessage);
	}

	void BackendDispatcher::reportProtocolError(Optional<long> relatedRequestId, CommonErrorCode errorCode, const String& errorMessage)
	{
	ASSERT_ARG(errorCode, errorCode >= 0);

	// If the error was reported from an async callback, then no request id will be registered yet.
	if (!m_currentRequestId)
	m_currentRequestId = relatedRequestId;

	m_protocolErrors.append(std::tuple<CommonErrorCode, String>(errorCode, errorMessage));
	}

	template<typename T>
	T BackendDispatcher::getPropertyValue(InspectorObject* object, const String& name, bool* out_optionalValueFound, T defaultValue, std::function<bool(InspectorValue&, T&)> asMethod, const char* typeName)
	{
	T result(defaultValue);
	// out_optionalValueFound signals to the caller whether an optional property was found.
	// if out_optionalValueFound == nullptr, then this is a required property.
	if (out_optionalValueFound)
	*out_optionalValueFound = false;

	if (!object) {
	if (!out_optionalValueFound)
	reportProtocolError(BackendDispatcher::InvalidParams, String::format("'params' object must contain required parameter '%s' with type '%s'.", name.utf8().data(), typeName));
	return result;
	}

	auto findResult = object->find(name);
	if (findResult == object->end()) {
	if (!out_optionalValueFound)
	reportProtocolError(BackendDispatcher::InvalidParams, String::format("Parameter '%s' with type '%s' was not found.", name.utf8().data(), typeName));
	return result;
	}

	if (!asMethod(*findResult->value, result)) {
	reportProtocolError(BackendDispatcher::InvalidParams, String::format("Parameter '%s' has wrong type. It must be '%s'.", name.utf8().data(), typeName));
	return result;
	}

	if (out_optionalValueFound)
	*out_optionalValueFound = true;

	return result;
	}

	static bool castToInteger(InspectorValue& value, int& result) { return value.asInteger(result); }
	static bool castToNumber(InspectorValue& value, double& result) { return value.asDouble(result); }

	int BackendDispatcher::getInteger(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<int>(object, name, valueFound, 0, &castToInteger, "Integer");
	}

	double BackendDispatcher::getDouble(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<double>(object, name, valueFound, 0, &castToNumber, "Number");
	}

	String BackendDispatcher::getString(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<String>(object, name, valueFound, "", &InspectorValue::asString, "String");
	}

	bool BackendDispatcher::getBoolean(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<bool>(object, name, valueFound, false, &InspectorValue::asBoolean, "Boolean");
	}

	RefPtr<InspectorObject> BackendDispatcher::getObject(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<RefPtr<InspectorObject>>(object, name, valueFound, nullptr, &InspectorValue::asObject, "Object");
	}

	RefPtr<InspectorArray> BackendDispatcher::getArray(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<RefPtr<InspectorArray>>(object, name, valueFound, nullptr, &InspectorValue::asArray, "Array");
	}

	RefPtr<InspectorValue> BackendDispatcher::getValue(InspectorObject* object, const String& name, bool* valueFound)
	{
	return getPropertyValue<RefPtr<InspectorValue>>(object, name, valueFound, nullptr, &InspectorValue::asValue, "Value");
	}

	} // namespace Inspector