Mozilla/mozilla/js/tamarin/core/ClassClosure.cpp

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 * 1.1 (the "License"); you may not use this file except in compliance with
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 * The Original Code is [Open Source Virtual Machine.].
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#include "avmplus.h"


namespace avmplus
{
	ClassClosure::ClassClosure(VTable *cvtable)
		: ScriptObject(cvtable, NULL)
	{
		AvmAssert(traits()->sizeofInstance >= sizeof(ClassClosure));

		// prototype will be set by caller
		AvmAssert(cvtable->traits->itraits != NULL);
		AvmAssert(ivtable() != NULL);
	}

	void ClassClosure::createVanillaPrototype()
	{
        prototype = toplevel()->objectClass->construct();
	}

	Atom ClassClosure::get_prototype()
	{
		// Illegal to apply this getter to anything but instances of Class
		// (verifier should ensure this)
		return prototype ? prototype->atom() : undefinedAtom;
	}

	void ClassClosure::set_prototype(Atom value)
	{
		// ISSUE can value be null/undefined?

		if (AvmCore::isNullOrUndefined(value))
		{
			this->prototype = NULL;
		}
		else
		{
			if (!AvmCore::isObject(value))
			{
				toplevel()->throwTypeError(kPrototypeTypeError);
			}

			// allow any prototype object.  if the object has methods or slots, so be it
			this->prototype = AvmCore::atomToScriptObject(value);
		}
	}

	VTable* ClassClosure::ivtable() const
	{
		return vtable->ivtable;
	}

	// this = argv[0] (ignored)
	// arg1 = argv[1]
	// argN = argv[argc]
	Atom ClassClosure::construct(int argc, Atom* argv)
	{
		VTable* ivtable = this->ivtable();
		AvmAssert(ivtable != NULL);
		AvmAssert(argv != NULL); // need at least one arg spot passed in
		if (prototype == NULL) // ES3 spec, 13.2.2 (we've already ensured prototype is either an Object or null)
			prototype = AvmCore::atomToScriptObject(toplevel()->objectClass->get_prototype());

		ScriptObject *obj = createInstance(ivtable, prototype);

		if (vtable->call != NULL)
		{
			// this is a function
			argv[0] = obj->atom(); // new object is receiver
			MethodEnv* call = vtable->call;
			Atom result = call->coerceEnter(argc, argv);

			// for E3 13.2.2 compliance, check result and return it if (Type(result) is Object)

			/* ISSUE does this apply to class constructors too?

			answer: no.  from E4: A constructor may invoke a return statement as long as that 
			statement does not supply a value; a constructor cannot return a value. The newly 
			created object is returned automatically. A constructor’s return type must be omitted. 
			A constructor always returns a new instance. */

			return AvmCore::isNull(result) || AvmCore::isObject(result) ? result : obj->atom();
		}
		else
		{
			// this is a class
			Atom a = obj->atom();
			argv[0] = a; // new object is receiver
			ivtable->init->coerceEnter(argc, argv);
			// this is a class. always return new instance.
			return a;
		}
	}

	// this = argv[0]
	// arg1 = argv[1]
	// argN = argv[argc]
	Atom ClassClosure::call(int argc, Atom* argv)
	{
		MethodEnv* call = vtable->call;
		Toplevel* toplevel = this->toplevel();
		if (call)
		{
			// invoke function body
			// TODO if we kept track of a type's call signature we could do this at verify time
			if (AvmCore::isNullOrUndefined(argv[0]))
			{
				// use callee's global object as this.
				// see E3 15.3.4.4
				AvmAssert(call->vtable->scope->getSize() > 0);
				argv[0] = call->vtable->scope->getScope(0);
			}

			// make sure receiver is legal for callee
			argv[0] = toplevel->coerce(argv[0], call->method->paramTraits(0));

			return call->coerceEnter(argc, argv);
		}
		else
		{
			// explicit coercion of a class object.
			if (argc != 1)
			{
				toplevel->throwArgumentError(kCoerceArgumentCountError, toplevel->core()->toErrorString(argc));
			}
			return toplevel->coerce(argv[1], (Traits*)ivtable()->traits);
		}
	}

	int ClassClosure::get_length()
	{
		MethodEnv* call = vtable->call;
		if (call)
			return call->method->param_count;
		else
			return vtable->init->method->param_count;
	}

#ifdef DEBUGGER
	uint32 ClassClosure::size() const
	{
		uint32 size = ScriptObject::size();
		size += vtable->size();
		return size;
	}
#endif

#ifdef AVMPLUS_VERBOSE
	Stringp ClassClosure::format(AvmCore* core) const
	{
		if (traits()->name)
		{
			return traits()->format(core);
		}
		else
		{
			Stringp prefix = core->newString("CC{}@");
			return core->concatStrings(prefix, core->formatAtomPtr(atom()));
		}
	}
#endif
}