Source/WebCore/bridge/c/c_instance.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2003-2019 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:
  * 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"

 #if ENABLE(NETSCAPE_PLUGIN_API)

 #include "c_instance.h"

 #include "CRuntimeObject.h"
 #include "IdentifierRep.h"
 #include "JSDOMBinding.h"
 #include "c_class.h"
 #include "c_runtime.h"
 #include "c_utility.h"
 #include "npruntime_impl.h"
 #include "runtime_method.h"
 #include "runtime_root.h"
 #include <JavaScriptCore/ArgList.h>
 #include <JavaScriptCore/CallFrame.h>
 #include <JavaScriptCore/Error.h>
 #include <JavaScriptCore/FunctionPrototype.h>
 #include <JavaScriptCore/JSLock.h>
 #include <JavaScriptCore/PropertyNameArray.h>
 #include <wtf/Assertions.h>
 #include <wtf/NeverDestroyed.h>
 #include <wtf/StdLibExtras.h>
 #include <wtf/Vector.h>

 using namespace WebCore;

 namespace JSC {
 namespace Bindings {

 static String& globalExceptionString()
 {
     static NeverDestroyed<String> exceptionStr;
     return exceptionStr;
 }

 void CInstance::setGlobalException(String exception)
 {
     globalExceptionString() = exception;
 }

 void CInstance::moveGlobalExceptionToExecState(ExecState* exec)
 {
     if (globalExceptionString().isNull())
         return;

     {
         VM& vm = exec->vm();
         JSLockHolder lock(vm);
         auto scope = DECLARE_THROW_SCOPE(vm);
         throwException(exec, scope, createError(exec, globalExceptionString()));
     }

     globalExceptionString() = String();
 }

 CInstance::CInstance(NPObject* o, RefPtr<RootObject>&& rootObject)
     : Instance(WTFMove(rootObject))
 {
     _object = _NPN_RetainObject(o);
     _class = 0;
 }

 CInstance::~CInstance()
 {
     _NPN_ReleaseObject(_object);
 }

 RuntimeObject* CInstance::newRuntimeObject(ExecState* exec)
 {
     // FIXME: deprecatedGetDOMStructure uses the prototype off of the wrong global object.
     return CRuntimeObject::create(exec->vm(), WebCore::deprecatedGetDOMStructure<CRuntimeObject>(exec), this);
 }

 Class *CInstance::getClass() const
 {
     if (!_class)
         _class = CClass::classForIsA(_object->_class);
     return _class;
 }

 bool CInstance::supportsInvokeDefaultMethod() const
 {
     return _object->_class->invokeDefault;
 }

 class CRuntimeMethod : public RuntimeMethod {
 public:
     typedef RuntimeMethod Base;

     static CRuntimeMethod* create(ExecState* exec, JSGlobalObject* globalObject, const String& name, Bindings::Method* method)
     {
         VM& vm = globalObject->vm();
         // FIXME: deprecatedGetDOMStructure uses the prototype off of the wrong global object
         // We need to pass in the right global object for "i".
         Structure* domStructure = WebCore::deprecatedGetDOMStructure<CRuntimeMethod>(exec);
         CRuntimeMethod* runtimeMethod = new (NotNull, allocateCell<CRuntimeMethod>(vm.heap)) CRuntimeMethod(globalObject, domStructure, method);
         runtimeMethod->finishCreation(vm, name);
         return runtimeMethod;
     }

     static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
     {
         return Structure::create(vm, globalObject, prototype, TypeInfo(InternalFunctionType, StructureFlags), info());
     }

     DECLARE_INFO;

 private:
     CRuntimeMethod(JSGlobalObject* globalObject, Structure* structure, Bindings::Method* method)
         : RuntimeMethod(globalObject, structure, method)
     {
     }

     void finishCreation(VM& vm, const String& name)
     {
         Base::finishCreation(vm, name);
         ASSERT(inherits(vm, info()));
     }

 };

 const ClassInfo CRuntimeMethod::s_info = { "CRuntimeMethod", &RuntimeMethod::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(CRuntimeMethod) };

 JSValue CInstance::getMethod(ExecState* exec, PropertyName propertyName)
 {
     Method* method = getClass()->methodNamed(propertyName, this);
     return CRuntimeMethod::create(exec, exec->lexicalGlobalObject(), propertyName.publicName(), method);
 }

 JSValue CInstance::invokeMethod(ExecState* exec, RuntimeMethod* runtimeMethod)
 {
     VM& vm = exec->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (!asObject(runtimeMethod)->inherits<CRuntimeMethod>(vm))
         return throwTypeError(exec, scope, "Attempt to invoke non-plug-in method on plug-in object."_s);

     CMethod* method = static_cast<CMethod*>(runtimeMethod->method());
     ASSERT(method);

     NPIdentifier ident = method->identifier();
     if (!_object->_class->hasMethod(_object, ident))
         return jsUndefined();

     unsigned count = exec->argumentCount();
     Vector<NPVariant, 8> cArgs(count);

     unsigned i;
     for (i = 0; i < count; i++)
         convertValueToNPVariant(exec, exec->uncheckedArgument(i), &cArgs[i]);

     // Invoke the 'C' method.
     bool retval = true;
     NPVariant resultVariant;
     VOID_TO_NPVARIANT(resultVariant);

     {
         JSLock::DropAllLocks dropAllLocks(exec);
         ASSERT(globalExceptionString().isNull());
         retval = _object->_class->invoke(_object, ident, cArgs.data(), count, &resultVariant);
         moveGlobalExceptionToExecState(exec);
     }

     if (!retval)
         throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

     for (i = 0; i < count; i++)
         _NPN_ReleaseVariantValue(&cArgs[i]);

     JSValue resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
     _NPN_ReleaseVariantValue(&resultVariant);
     return resultValue;
 }


 JSValue CInstance::invokeDefaultMethod(ExecState* exec)
 {
     VM& vm = exec->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (!_object->_class->invokeDefault)
         return jsUndefined();

     unsigned count = exec->argumentCount();
     Vector<NPVariant, 8> cArgs(count);

     unsigned i;
     for (i = 0; i < count; i++)
         convertValueToNPVariant(exec, exec->uncheckedArgument(i), &cArgs[i]);

     // Invoke the 'C' method.
     bool retval = true;
     NPVariant resultVariant;
     VOID_TO_NPVARIANT(resultVariant);
     {
         JSLock::DropAllLocks dropAllLocks(exec);
         ASSERT(globalExceptionString().isNull());
         retval = _object->_class->invokeDefault(_object, cArgs.data(), count, &resultVariant);
         moveGlobalExceptionToExecState(exec);
     }

     if (!retval)
         throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

     for (i = 0; i < count; i++)
         _NPN_ReleaseVariantValue(&cArgs[i]);

     JSValue resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
     _NPN_ReleaseVariantValue(&resultVariant);
     return resultValue;
 }

 bool CInstance::supportsConstruct() const
 {
     return _object->_class->construct;
 }

 JSValue CInstance::invokeConstruct(ExecState* exec, const ArgList& args)
 {
     VM& vm = exec->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (!_object->_class->construct)
         return jsUndefined();

     unsigned count = args.size();
     Vector<NPVariant, 8> cArgs(count);

     unsigned i;
     for (i = 0; i < count; i++)
         convertValueToNPVariant(exec, args.at(i), &cArgs[i]);

     // Invoke the 'C' method.
     bool retval = true;
     NPVariant resultVariant;
     VOID_TO_NPVARIANT(resultVariant);
     {
         JSLock::DropAllLocks dropAllLocks(exec);
         ASSERT(globalExceptionString().isNull());
         retval = _object->_class->construct(_object, cArgs.data(), count, &resultVariant);
         moveGlobalExceptionToExecState(exec);
     }

     if (!retval)
         throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

     for (i = 0; i < count; i++)
         _NPN_ReleaseVariantValue(&cArgs[i]);

     JSValue resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
     _NPN_ReleaseVariantValue(&resultVariant);
     return resultValue;
 }

 JSValue CInstance::defaultValue(ExecState* exec, PreferredPrimitiveType hint) const
 {
     if (hint == PreferString)
         return stringValue(exec);
     if (hint == PreferNumber)
         return numberValue(exec);
     return valueOf(exec);
 }

 JSValue CInstance::stringValue(ExecState* exec) const
 {
     JSValue value;
     if (toJSPrimitive(exec, "toString", value))
         return value;

     // Fallback to default implementation.
     return jsNontrivialString(exec->vm(), "NPObject"_s);
 }

 JSValue CInstance::numberValue(ExecState*) const
 {
     // FIXME: Implement something sensible.
     return jsNumber(0);
 }

 JSValue CInstance::booleanValue() const
 {
     // As per ECMA 9.2.
     return jsBoolean(getObject());
 }

 JSValue CInstance::valueOf(ExecState* exec) const
 {
     JSValue value;
     if (toJSPrimitive(exec, "valueOf", value))
         return value;

     // Fallback to default implementation.
     return stringValue(exec);
 }

 bool CInstance::toJSPrimitive(ExecState* exec, const char* name, JSValue& resultValue) const
 {
     VM& vm = exec->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     NPIdentifier ident = _NPN_GetStringIdentifier(name);
     if (!_object->_class->hasMethod(_object, ident))
         return false;

     // Invoke the 'C' method.
     bool retval = true;
     NPVariant resultVariant;
     VOID_TO_NPVARIANT(resultVariant);

     {
         JSLock::DropAllLocks dropAllLocks(exec);
         ASSERT(globalExceptionString().isNull());
         retval = _object->_class->invoke(_object, ident, 0, 0, &resultVariant);
         moveGlobalExceptionToExecState(exec);
     }

     if (!retval)
         throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

     resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
     _NPN_ReleaseVariantValue(&resultVariant);
     return true;
 }

 void CInstance::getPropertyNames(ExecState* exec, PropertyNameArray& nameArray)
 {
     if (!NP_CLASS_STRUCT_VERSION_HAS_ENUM(_object->_class) || !_object->_class->enumerate)
         return;

     uint32_t count;
     NPIdentifier* identifiers;

     {
         JSLock::DropAllLocks dropAllLocks(exec);
         ASSERT(globalExceptionString().isNull());
         bool ok = _object->_class->enumerate(_object, &identifiers, &count);
         moveGlobalExceptionToExecState(exec);
         if (!ok)
             return;
     }

     VM& vm = exec->vm();
     for (uint32_t i = 0; i < count; i++) {
         IdentifierRep* identifier = static_cast<IdentifierRep*>(identifiers[i]);

         if (identifier->isString())
             nameArray.add(identifierFromNPIdentifier(exec, identifier->string()));
         else
             nameArray.add(Identifier::from(vm, identifier->number()));
     }

     // FIXME: This should really call NPN_MemFree but that's in WebKit
     free(identifiers);
 }

 }
 }

 #endif // ENABLE(NETSCAPE_PLUGIN_API)
	/*
	* Copyright (C) 2003-2019 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:
	* 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"

	#if ENABLE(NETSCAPE_PLUGIN_API)

	#include "c_instance.h"

	#include "CRuntimeObject.h"
	#include "IdentifierRep.h"
	#include "JSDOMBinding.h"
	#include "c_class.h"
	#include "c_runtime.h"
	#include "c_utility.h"
	#include "npruntime_impl.h"
	#include "runtime_method.h"
	#include "runtime_root.h"
	#include <JavaScriptCore/ArgList.h>
	#include <JavaScriptCore/CallFrame.h>
	#include <JavaScriptCore/Error.h>
	#include <JavaScriptCore/FunctionPrototype.h>
	#include <JavaScriptCore/JSLock.h>
	#include <JavaScriptCore/PropertyNameArray.h>
	#include <wtf/Assertions.h>
	#include <wtf/NeverDestroyed.h>
	#include <wtf/StdLibExtras.h>
	#include <wtf/Vector.h>

	using namespace WebCore;

	namespace JSC {
	namespace Bindings {

	static String& globalExceptionString()
	{
	static NeverDestroyed<String> exceptionStr;
	return exceptionStr;
	}

	void CInstance::setGlobalException(String exception)
	{
	globalExceptionString() = exception;
	}

	void CInstance::moveGlobalExceptionToExecState(ExecState* exec)
	{
	if (globalExceptionString().isNull())
	return;

	{
	VM& vm = exec->vm();
	JSLockHolder lock(vm);
	auto scope = DECLARE_THROW_SCOPE(vm);
	throwException(exec, scope, createError(exec, globalExceptionString()));
	}

	globalExceptionString() = String();
	}

	CInstance::CInstance(NPObject* o, RefPtr<RootObject>&& rootObject)
	: Instance(WTFMove(rootObject))
	{
	_object = _NPN_RetainObject(o);
	_class = 0;
	}

	CInstance::~CInstance()
	{
	_NPN_ReleaseObject(_object);
	}

	RuntimeObject* CInstance::newRuntimeObject(ExecState* exec)
	{
	// FIXME: deprecatedGetDOMStructure uses the prototype off of the wrong global object.
	return CRuntimeObject::create(exec->vm(), WebCore::deprecatedGetDOMStructure<CRuntimeObject>(exec), this);
	}

	Class *CInstance::getClass() const
	{
	if (!_class)
	_class = CClass::classForIsA(_object->_class);
	return _class;
	}

	bool CInstance::supportsInvokeDefaultMethod() const
	{
	return _object->_class->invokeDefault;
	}

	class CRuntimeMethod : public RuntimeMethod {
	public:
	typedef RuntimeMethod Base;

	static CRuntimeMethod* create(ExecState* exec, JSGlobalObject* globalObject, const String& name, Bindings::Method* method)
	{
	VM& vm = globalObject->vm();
	// FIXME: deprecatedGetDOMStructure uses the prototype off of the wrong global object
	// We need to pass in the right global object for "i".
	Structure* domStructure = WebCore::deprecatedGetDOMStructure<CRuntimeMethod>(exec);
	CRuntimeMethod* runtimeMethod = new (NotNull, allocateCell<CRuntimeMethod>(vm.heap)) CRuntimeMethod(globalObject, domStructure, method);
	runtimeMethod->finishCreation(vm, name);
	return runtimeMethod;
	}

	static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
	{
	return Structure::create(vm, globalObject, prototype, TypeInfo(InternalFunctionType, StructureFlags), info());
	}

	DECLARE_INFO;

	private:
	CRuntimeMethod(JSGlobalObject* globalObject, Structure* structure, Bindings::Method* method)
	: RuntimeMethod(globalObject, structure, method)
	{
	}

	void finishCreation(VM& vm, const String& name)
	{
	Base::finishCreation(vm, name);
	ASSERT(inherits(vm, info()));
	}

	};

	const ClassInfo CRuntimeMethod::s_info = { "CRuntimeMethod", &RuntimeMethod::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(CRuntimeMethod) };

	JSValue CInstance::getMethod(ExecState* exec, PropertyName propertyName)
	{
	Method* method = getClass()->methodNamed(propertyName, this);
	return CRuntimeMethod::create(exec, exec->lexicalGlobalObject(), propertyName.publicName(), method);
	}

	JSValue CInstance::invokeMethod(ExecState* exec, RuntimeMethod* runtimeMethod)
	{
	VM& vm = exec->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (!asObject(runtimeMethod)->inherits<CRuntimeMethod>(vm))
	return throwTypeError(exec, scope, "Attempt to invoke non-plug-in method on plug-in object."_s);

	CMethod* method = static_cast<CMethod*>(runtimeMethod->method());
	ASSERT(method);

	NPIdentifier ident = method->identifier();
	if (!_object->_class->hasMethod(_object, ident))
	return jsUndefined();

	unsigned count = exec->argumentCount();
	Vector<NPVariant, 8> cArgs(count);

	unsigned i;
	for (i = 0; i < count; i++)
	convertValueToNPVariant(exec, exec->uncheckedArgument(i), &cArgs[i]);

	// Invoke the 'C' method.
	bool retval = true;
	NPVariant resultVariant;
	VOID_TO_NPVARIANT(resultVariant);

	{
	JSLock::DropAllLocks dropAllLocks(exec);
	ASSERT(globalExceptionString().isNull());
	retval = _object->_class->invoke(_object, ident, cArgs.data(), count, &resultVariant);
	moveGlobalExceptionToExecState(exec);
	}

	if (!retval)
	throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

	for (i = 0; i < count; i++)
	_NPN_ReleaseVariantValue(&cArgs[i]);

	JSValue resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
	_NPN_ReleaseVariantValue(&resultVariant);
	return resultValue;
	}


	JSValue CInstance::invokeDefaultMethod(ExecState* exec)
	{
	VM& vm = exec->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (!_object->_class->invokeDefault)
	return jsUndefined();

	unsigned count = exec->argumentCount();
	Vector<NPVariant, 8> cArgs(count);

	unsigned i;
	for (i = 0; i < count; i++)
	convertValueToNPVariant(exec, exec->uncheckedArgument(i), &cArgs[i]);

	// Invoke the 'C' method.
	bool retval = true;
	NPVariant resultVariant;
	VOID_TO_NPVARIANT(resultVariant);
	{
	JSLock::DropAllLocks dropAllLocks(exec);
	ASSERT(globalExceptionString().isNull());
	retval = _object->_class->invokeDefault(_object, cArgs.data(), count, &resultVariant);
	moveGlobalExceptionToExecState(exec);
	}

	if (!retval)
	throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

	for (i = 0; i < count; i++)
	_NPN_ReleaseVariantValue(&cArgs[i]);

	JSValue resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
	_NPN_ReleaseVariantValue(&resultVariant);
	return resultValue;
	}

	bool CInstance::supportsConstruct() const
	{
	return _object->_class->construct;
	}

	JSValue CInstance::invokeConstruct(ExecState* exec, const ArgList& args)
	{
	VM& vm = exec->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (!_object->_class->construct)
	return jsUndefined();

	unsigned count = args.size();
	Vector<NPVariant, 8> cArgs(count);

	unsigned i;
	for (i = 0; i < count; i++)
	convertValueToNPVariant(exec, args.at(i), &cArgs[i]);

	// Invoke the 'C' method.
	bool retval = true;
	NPVariant resultVariant;
	VOID_TO_NPVARIANT(resultVariant);
	{
	JSLock::DropAllLocks dropAllLocks(exec);
	ASSERT(globalExceptionString().isNull());
	retval = _object->_class->construct(_object, cArgs.data(), count, &resultVariant);
	moveGlobalExceptionToExecState(exec);
	}

	if (!retval)
	throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

	for (i = 0; i < count; i++)
	_NPN_ReleaseVariantValue(&cArgs[i]);

	JSValue resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
	_NPN_ReleaseVariantValue(&resultVariant);
	return resultValue;
	}

	JSValue CInstance::defaultValue(ExecState* exec, PreferredPrimitiveType hint) const
	{
	if (hint == PreferString)
	return stringValue(exec);
	if (hint == PreferNumber)
	return numberValue(exec);
	return valueOf(exec);
	}

	JSValue CInstance::stringValue(ExecState* exec) const
	{
	JSValue value;
	if (toJSPrimitive(exec, "toString", value))
	return value;

	// Fallback to default implementation.
	return jsNontrivialString(exec->vm(), "NPObject"_s);
	}

	JSValue CInstance::numberValue(ExecState*) const
	{
	// FIXME: Implement something sensible.
	return jsNumber(0);
	}

	JSValue CInstance::booleanValue() const
	{
	// As per ECMA 9.2.
	return jsBoolean(getObject());
	}

	JSValue CInstance::valueOf(ExecState* exec) const
	{
	JSValue value;
	if (toJSPrimitive(exec, "valueOf", value))
	return value;

	// Fallback to default implementation.
	return stringValue(exec);
	}

	bool CInstance::toJSPrimitive(ExecState* exec, const char* name, JSValue& resultValue) const
	{
	VM& vm = exec->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	NPIdentifier ident = _NPN_GetStringIdentifier(name);
	if (!_object->_class->hasMethod(_object, ident))
	return false;

	// Invoke the 'C' method.
	bool retval = true;
	NPVariant resultVariant;
	VOID_TO_NPVARIANT(resultVariant);

	{
	JSLock::DropAllLocks dropAllLocks(exec);
	ASSERT(globalExceptionString().isNull());
	retval = _object->_class->invoke(_object, ident, 0, 0, &resultVariant);
	moveGlobalExceptionToExecState(exec);
	}

	if (!retval)
	throwException(exec, scope, createError(exec, "Error calling method on NPObject."_s));

	resultValue = convertNPVariantToValue(exec, &resultVariant, m_rootObject.get());
	_NPN_ReleaseVariantValue(&resultVariant);
	return true;
	}

	void CInstance::getPropertyNames(ExecState* exec, PropertyNameArray& nameArray)
	{
	if (!NP_CLASS_STRUCT_VERSION_HAS_ENUM(_object->_class) \|\| !_object->_class->enumerate)
	return;

	uint32_t count;
	NPIdentifier* identifiers;

	{
	JSLock::DropAllLocks dropAllLocks(exec);
	ASSERT(globalExceptionString().isNull());
	bool ok = _object->_class->enumerate(_object, &identifiers, &count);
	moveGlobalExceptionToExecState(exec);
	if (!ok)
	return;
	}

	VM& vm = exec->vm();
	for (uint32_t i = 0; i < count; i++) {
	IdentifierRep* identifier = static_cast<IdentifierRep*>(identifiers[i]);

	if (identifier->isString())
	nameArray.add(identifierFromNPIdentifier(exec, identifier->string()));
	else
	nameArray.add(Identifier::from(vm, identifier->number()));
	}

	// FIXME: This should really call NPN_MemFree but that's in WebKit
	free(identifiers);
	}

	}
	}

	#endif // ENABLE(NETSCAPE_PLUGIN_API)