mirror of
https://github.com/mozilla/gecko-dev.git
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995 lines
38 KiB
C++
995 lines
38 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: set ts=8 sts=4 et sw=4 tw=99:
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* JSClass definition and its component types, plus related interfaces. */
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#ifndef js_Class_h
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#define js_Class_h
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#include "jstypes.h"
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#include "js/CallArgs.h"
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#include "js/Id.h"
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#include "js/TypeDecls.h"
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/*
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* A JSClass acts as a vtable for JS objects that allows JSAPI clients to
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* control various aspects of the behavior of an object like property lookup.
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* js::Class is an engine-private extension that allows more control over
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* object behavior and, e.g., allows custom slow layout.
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*/
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struct JSAtomState;
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struct JSFreeOp;
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struct JSFunctionSpec;
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namespace js {
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struct Class;
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class FreeOp;
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class Shape;
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// This is equal to JSFunction::class_. Use it in places where you don't want
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// to #include jsfun.h.
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extern JS_FRIEND_DATA(const js::Class* const) FunctionClassPtr;
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} // namespace js
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namespace JS {
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template <typename T>
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class AutoVectorRooter;
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typedef AutoVectorRooter<jsid> AutoIdVector;
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/**
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* The answer to a successful query as to whether an object is an Array per
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* ES6's internal |IsArray| operation (as exposed by |Array.isArray|).
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*/
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enum class IsArrayAnswer
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{
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Array,
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NotArray,
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RevokedProxy
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};
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/**
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* ES6 7.2.2.
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*
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* Returns false on failure, otherwise returns true and sets |*isArray|
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* indicating whether the object passes ECMAScript's IsArray test. This is the
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* same test performed by |Array.isArray|.
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*
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* This is NOT the same as asking whether |obj| is an Array or a wrapper around
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* one. If |obj| is a proxy created by |Proxy.revocable()| and has been
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* revoked, or if |obj| is a proxy whose target (at any number of hops) is a
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* revoked proxy, this method throws a TypeError and returns false.
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*/
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extern JS_PUBLIC_API(bool)
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IsArray(JSContext* cx, HandleObject obj, bool* isArray);
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/**
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* Identical to IsArray above, but the nature of the object (if successfully
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* determined) is communicated via |*answer|. In particular this method
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* returns true and sets |*answer = IsArrayAnswer::RevokedProxy| when called on
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* a revoked proxy.
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*
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* Most users will want the overload above, not this one.
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*/
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extern JS_PUBLIC_API(bool)
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IsArray(JSContext* cx, HandleObject obj, IsArrayAnswer* answer);
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/**
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* Per ES6, the [[DefineOwnProperty]] internal method has three different
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* possible outcomes:
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*
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* - It can throw an exception (which we indicate by returning false).
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*
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* - It can return true, indicating unvarnished success.
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*
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* - It can return false, indicating "strict failure". The property could
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* not be defined. It's an error, but no exception was thrown.
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*
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* It's not just [[DefineOwnProperty]]: all the mutating internal methods have
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* the same three outcomes. (The other affected internal methods are [[Set]],
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* [[Delete]], [[SetPrototypeOf]], and [[PreventExtensions]].)
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*
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* If you think this design is awful, you're not alone. But as it's the
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* standard, we must represent these boolean "success" values somehow.
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* ObjectOpSuccess is the class for this. It's like a bool, but when it's false
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* it also stores an error code.
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*
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* Typical usage:
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*
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* ObjectOpResult result;
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* if (!DefineProperty(cx, obj, id, ..., result))
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* return false;
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* if (!result)
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* return result.reportError(cx, obj, id);
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*
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* Users don't have to call `result.report()`; another possible ending is:
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*
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* argv.rval().setBoolean(bool(result));
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* return true;
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*/
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class ObjectOpResult
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{
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private:
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/**
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* code_ is either one of the special codes OkCode or Uninitialized, or
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* an error code. For now the error codes are private to the JS engine;
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* they're defined in js/src/js.msg.
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*
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* code_ is uintptr_t (rather than uint32_t) for the convenience of the
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* JITs, which would otherwise have to deal with either padding or stack
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* alignment on 64-bit platforms.
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*/
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uintptr_t code_;
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public:
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enum SpecialCodes : uintptr_t {
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OkCode = 0,
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Uninitialized = uintptr_t(-1)
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};
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ObjectOpResult() : code_(Uninitialized) {}
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/* Return true if succeed() was called. */
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bool ok() const {
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MOZ_ASSERT(code_ != Uninitialized);
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return code_ == OkCode;
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}
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explicit operator bool() const { return ok(); }
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/* Set this ObjectOpResult to true and return true. */
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bool succeed() {
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code_ = OkCode;
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return true;
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}
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/*
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* Set this ObjectOpResult to false with an error code.
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*
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* Always returns true, as a convenience. Typical usage will be:
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*
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* if (funny condition)
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* return result.fail(JSMSG_CANT_DO_THE_THINGS);
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*
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* The true return value indicates that no exception is pending, and it
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* would be OK to ignore the failure and continue.
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*/
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bool fail(uint32_t msg) {
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MOZ_ASSERT(msg != OkCode);
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code_ = msg;
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return true;
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}
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JS_PUBLIC_API(bool) failCantRedefineProp();
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JS_PUBLIC_API(bool) failReadOnly();
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JS_PUBLIC_API(bool) failGetterOnly();
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JS_PUBLIC_API(bool) failCantDelete();
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JS_PUBLIC_API(bool) failCantSetInterposed();
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JS_PUBLIC_API(bool) failCantDefineWindowElement();
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JS_PUBLIC_API(bool) failCantDeleteWindowElement();
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JS_PUBLIC_API(bool) failCantDeleteWindowNamedProperty();
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JS_PUBLIC_API(bool) failCantPreventExtensions();
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JS_PUBLIC_API(bool) failCantSetProto();
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JS_PUBLIC_API(bool) failNoNamedSetter();
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JS_PUBLIC_API(bool) failNoIndexedSetter();
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uint32_t failureCode() const {
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MOZ_ASSERT(!ok());
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return uint32_t(code_);
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}
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/*
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* Report an error or warning if necessary; return true to proceed and
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* false if an error was reported. Call this when failure should cause
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* a warning if extraWarnings are enabled.
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*
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* The precise rules are like this:
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*
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* - If ok(), then we succeeded. Do nothing and return true.
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* - Otherwise, if |strict| is true, or if cx has both extraWarnings and
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* werrorOption enabled, throw a TypeError and return false.
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* - Otherwise, if cx has extraWarnings enabled, emit a warning and
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* return true.
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* - Otherwise, do nothing and return true.
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*/
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bool checkStrictErrorOrWarning(JSContext* cx, HandleObject obj, HandleId id, bool strict) {
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if (ok())
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return true;
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return reportStrictErrorOrWarning(cx, obj, id, strict);
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}
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/*
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* The same as checkStrictErrorOrWarning(cx, id, strict), except the
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* operation is not associated with a particular property id. This is
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* used for [[PreventExtensions]] and [[SetPrototypeOf]]. failureCode()
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* must not be an error that has "{0}" in the error message.
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*/
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bool checkStrictErrorOrWarning(JSContext* cx, HandleObject obj, bool strict) {
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return ok() || reportStrictErrorOrWarning(cx, obj, strict);
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}
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/* Throw a TypeError. Call this only if !ok(). */
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bool reportError(JSContext* cx, HandleObject obj, HandleId id) {
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return reportStrictErrorOrWarning(cx, obj, id, true);
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}
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/*
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* The same as reportError(cx, obj, id), except the operation is not
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* associated with a particular property id.
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*/
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bool reportError(JSContext* cx, HandleObject obj) {
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return reportStrictErrorOrWarning(cx, obj, true);
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}
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/* Helper function for checkStrictErrorOrWarning's slow path. */
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JS_PUBLIC_API(bool) reportStrictErrorOrWarning(JSContext* cx, HandleObject obj, HandleId id, bool strict);
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JS_PUBLIC_API(bool) reportStrictErrorOrWarning(JSContext* cx, HandleObject obj, bool strict);
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/*
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* Convenience method. Return true if ok() or if strict is false; otherwise
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* throw a TypeError and return false.
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*/
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bool checkStrict(JSContext* cx, HandleObject obj, HandleId id) {
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return checkStrictErrorOrWarning(cx, obj, id, true);
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}
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/*
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* Convenience method. The same as checkStrict(cx, id), except the
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* operation is not associated with a particular property id.
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*/
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bool checkStrict(JSContext* cx, HandleObject obj) {
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return checkStrictErrorOrWarning(cx, obj, true);
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}
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};
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} // namespace JS
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// JSClass operation signatures.
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/**
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* Get a property named by id in obj. Note the jsid id type -- id may
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* be a string (Unicode property identifier) or an int (element index). The
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* *vp out parameter, on success, is the new property value after the action.
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*/
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typedef bool
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(* JSGetterOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::MutableHandleValue vp);
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/** Add a property named by id to obj. */
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typedef bool
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(* JSAddPropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id, JS::HandleValue v);
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/**
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* Set a property named by id in obj, treating the assignment as strict
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* mode code if strict is true. Note the jsid id type -- id may be a string
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* (Unicode property identifier) or an int (element index). The *vp out
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* parameter, on success, is the new property value after the
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* set.
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*/
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typedef bool
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(* JSSetterOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::MutableHandleValue vp, JS::ObjectOpResult& result);
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/**
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* Delete a property named by id in obj.
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*
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* If an error occurred, return false as per normal JSAPI error practice.
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*
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* If no error occurred, but the deletion attempt wasn't allowed (perhaps
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* because the property was non-configurable), call result.fail() and
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* return true. This will cause |delete obj[id]| to evaluate to false in
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* non-strict mode code, and to throw a TypeError in strict mode code.
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*
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* If no error occurred and the deletion wasn't disallowed (this is *not* the
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* same as saying that a deletion actually occurred -- deleting a non-existent
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* property, or an inherited property, is allowed -- it's just pointless),
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* call result.succeed() and return true.
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*/
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typedef bool
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(* JSDeletePropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::ObjectOpResult& result);
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/**
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* The type of ObjectOps::enumerate. This callback overrides a portion of
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* SpiderMonkey's default [[Enumerate]] internal method. When an ordinary object
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* is enumerated, that object and each object on its prototype chain is tested
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* for an enumerate op, and those ops are called in order. The properties each
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* op adds to the 'properties' vector are added to the set of values the for-in
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* loop will iterate over. All of this is nonstandard.
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*
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* An object is "enumerated" when it's the target of a for-in loop or
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* JS_Enumerate(). The callback's job is to populate 'properties' with the
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* object's property keys. If `enumerableOnly` is true, the callback should only
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* add enumerable properties.
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*/
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typedef bool
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(* JSNewEnumerateOp)(JSContext* cx, JS::HandleObject obj, JS::AutoIdVector& properties,
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bool enumerableOnly);
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/**
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* The old-style JSClass.enumerate op should define all lazy properties not
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* yet reflected in obj.
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*/
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typedef bool
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(* JSEnumerateOp)(JSContext* cx, JS::HandleObject obj);
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/**
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* The type of ObjectOps::funToString. This callback allows an object to
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* provide a custom string to use when Function.prototype.toString is invoked on
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* that object. A null return value means OOM.
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*/
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typedef JSString*
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(* JSFunToStringOp)(JSContext* cx, JS::HandleObject obj, unsigned indent);
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/**
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* Resolve a lazy property named by id in obj by defining it directly in obj.
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* Lazy properties are those reflected from some peer native property space
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* (e.g., the DOM attributes for a given node reflected as obj) on demand.
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*
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* JS looks for a property in an object, and if not found, tries to resolve
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* the given id. *resolvedp should be set to true iff the property was defined
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* on |obj|.
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*/
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typedef bool
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(* JSResolveOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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bool* resolvedp);
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/**
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* A class with a resolve hook can optionally have a mayResolve hook. This hook
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* must have no side effects and must return true for a given id if the resolve
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* hook may resolve this id. This is useful when we're doing a "pure" lookup: if
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* mayResolve returns false, we know we don't have to call the effectful resolve
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* hook.
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*
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* maybeObj, if non-null, is the object on which we're doing the lookup. This
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* can be nullptr: during JIT compilation we sometimes know the Class but not
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* the object.
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*/
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typedef bool
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(* JSMayResolveOp)(const JSAtomState& names, jsid id, JSObject* maybeObj);
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/**
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* Finalize obj, which the garbage collector has determined to be unreachable
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* from other live objects or from GC roots. Obviously, finalizers must never
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* store a reference to obj.
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*/
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typedef void
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(* JSFinalizeOp)(JSFreeOp* fop, JSObject* obj);
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/** Finalizes external strings created by JS_NewExternalString. */
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struct JSStringFinalizer {
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void (*finalize)(const JSStringFinalizer* fin, char16_t* chars);
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};
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/**
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* Check whether v is an instance of obj. Return false on error or exception,
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* true on success with true in *bp if v is an instance of obj, false in
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* *bp otherwise.
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*/
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typedef bool
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(* JSHasInstanceOp)(JSContext* cx, JS::HandleObject obj, JS::MutableHandleValue vp,
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bool* bp);
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/**
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* Function type for trace operation of the class called to enumerate all
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* traceable things reachable from obj's private data structure. For each such
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* thing, a trace implementation must call one of the JS_Call*Tracer variants
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* on the thing.
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*
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* JSTraceOp implementation can assume that no other threads mutates object
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* state. It must not change state of the object or corresponding native
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* structures. The only exception for this rule is the case when the embedding
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* needs a tight integration with GC. In that case the embedding can check if
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* the traversal is a part of the marking phase through calling
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* JS_IsGCMarkingTracer and apply a special code like emptying caches or
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* marking its native structures.
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*/
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typedef void
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(* JSTraceOp)(JSTracer* trc, JSObject* obj);
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typedef JSObject*
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(* JSWeakmapKeyDelegateOp)(JSObject* obj);
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typedef void
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(* JSObjectMovedOp)(JSObject* obj, const JSObject* old);
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/* js::Class operation signatures. */
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namespace js {
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typedef bool
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(* LookupPropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::MutableHandleObject objp, JS::MutableHandle<Shape*> propp);
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typedef bool
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(* DefinePropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::Handle<JS::PropertyDescriptor> desc,
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JS::ObjectOpResult& result);
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typedef bool
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(* HasPropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id, bool* foundp);
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typedef bool
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(* GetPropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleValue receiver, JS::HandleId id,
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JS::MutableHandleValue vp);
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typedef bool
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(* SetPropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id, JS::HandleValue v,
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JS::HandleValue receiver, JS::ObjectOpResult& result);
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typedef bool
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(* GetOwnPropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::MutableHandle<JS::PropertyDescriptor> desc);
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typedef bool
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(* DeletePropertyOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id,
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JS::ObjectOpResult& result);
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typedef bool
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(* WatchOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id, JS::HandleObject callable);
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typedef bool
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(* UnwatchOp)(JSContext* cx, JS::HandleObject obj, JS::HandleId id);
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class JS_FRIEND_API(ElementAdder)
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{
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public:
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enum GetBehavior {
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// Check if the element exists before performing the Get and preserve
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// holes.
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CheckHasElemPreserveHoles,
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// Perform a Get operation, like obj[index] in JS.
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GetElement
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};
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private:
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// Only one of these is used.
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JS::RootedObject resObj_;
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JS::Value* vp_;
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uint32_t index_;
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#ifdef DEBUG
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uint32_t length_;
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#endif
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GetBehavior getBehavior_;
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public:
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ElementAdder(JSContext* cx, JSObject* obj, uint32_t length, GetBehavior behavior)
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: resObj_(cx, obj), vp_(nullptr), index_(0),
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#ifdef DEBUG
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length_(length),
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#endif
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getBehavior_(behavior)
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{}
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ElementAdder(JSContext* cx, JS::Value* vp, uint32_t length, GetBehavior behavior)
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: resObj_(cx), vp_(vp), index_(0),
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#ifdef DEBUG
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length_(length),
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#endif
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getBehavior_(behavior)
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{}
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GetBehavior getBehavior() const { return getBehavior_; }
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bool append(JSContext* cx, JS::HandleValue v);
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void appendHole();
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};
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typedef bool
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(* GetElementsOp)(JSContext* cx, JS::HandleObject obj, uint32_t begin, uint32_t end,
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ElementAdder* adder);
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typedef void
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(* FinalizeOp)(FreeOp* fop, JSObject* obj);
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// The special treatment of |finalize| and |trace| is necessary because if we
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// assign either of those hooks to a local variable and then call it -- as is
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// done with the other hooks -- the GC hazard analysis gets confused.
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#define JS_CLASS_MEMBERS(ClassOpsType, FreeOpType) \
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const char* name; \
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uint32_t flags; \
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const ClassOpsType* cOps; \
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\
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JSAddPropertyOp getAddProperty() const { return cOps ? cOps->addProperty : nullptr; } \
|
|
JSDeletePropertyOp getDelProperty() const { return cOps ? cOps->delProperty : nullptr; } \
|
|
JSGetterOp getGetProperty() const { return cOps ? cOps->getProperty : nullptr; } \
|
|
JSSetterOp getSetProperty() const { return cOps ? cOps->setProperty : nullptr; } \
|
|
JSEnumerateOp getEnumerate() const { return cOps ? cOps->enumerate : nullptr; } \
|
|
JSResolveOp getResolve() const { return cOps ? cOps->resolve : nullptr; } \
|
|
JSMayResolveOp getMayResolve() const { return cOps ? cOps->mayResolve : nullptr; } \
|
|
JSNative getCall() const { return cOps ? cOps->call : nullptr; } \
|
|
JSHasInstanceOp getHasInstance() const { return cOps ? cOps->hasInstance : nullptr; } \
|
|
JSNative getConstruct() const { return cOps ? cOps->construct : nullptr; } \
|
|
\
|
|
bool hasFinalize() const { return cOps && cOps->finalize; } \
|
|
bool hasTrace() const { return cOps && cOps->trace; } \
|
|
\
|
|
bool isTrace(JSTraceOp trace) const { return cOps && cOps->trace == trace; } \
|
|
\
|
|
void doFinalize(FreeOpType* fop, JSObject* obj) const { \
|
|
MOZ_ASSERT(cOps && cOps->finalize); \
|
|
cOps->finalize(fop, obj); \
|
|
} \
|
|
void doTrace(JSTracer* trc, JSObject* obj) const { \
|
|
MOZ_ASSERT(cOps && cOps->trace); \
|
|
cOps->trace(trc, obj); \
|
|
}
|
|
|
|
struct ClassOps
|
|
{
|
|
/* Function pointer members (may be null). */
|
|
JSAddPropertyOp addProperty;
|
|
JSDeletePropertyOp delProperty;
|
|
JSGetterOp getProperty;
|
|
JSSetterOp setProperty;
|
|
JSEnumerateOp enumerate;
|
|
JSResolveOp resolve;
|
|
JSMayResolveOp mayResolve;
|
|
FinalizeOp finalize;
|
|
JSNative call;
|
|
JSHasInstanceOp hasInstance;
|
|
JSNative construct;
|
|
JSTraceOp trace;
|
|
};
|
|
|
|
/** Callback for the creation of constructor and prototype objects. */
|
|
typedef JSObject* (*ClassObjectCreationOp)(JSContext* cx, JSProtoKey key);
|
|
|
|
/** Callback for custom post-processing after class initialization via ClassSpec. */
|
|
typedef bool (*FinishClassInitOp)(JSContext* cx, JS::HandleObject ctor,
|
|
JS::HandleObject proto);
|
|
|
|
const size_t JSCLASS_CACHED_PROTO_WIDTH = 6;
|
|
|
|
struct ClassSpec
|
|
{
|
|
// All properties except flags should be accessed through accessor.
|
|
ClassObjectCreationOp createConstructor_;
|
|
ClassObjectCreationOp createPrototype_;
|
|
const JSFunctionSpec* constructorFunctions_;
|
|
const JSPropertySpec* constructorProperties_;
|
|
const JSFunctionSpec* prototypeFunctions_;
|
|
const JSPropertySpec* prototypeProperties_;
|
|
FinishClassInitOp finishInit_;
|
|
uintptr_t flags;
|
|
|
|
static const size_t ParentKeyWidth = JSCLASS_CACHED_PROTO_WIDTH;
|
|
|
|
static const uintptr_t ParentKeyMask = (1 << ParentKeyWidth) - 1;
|
|
static const uintptr_t DontDefineConstructor = 1 << ParentKeyWidth;
|
|
static const uintptr_t IsDelegated = 1 << (ParentKeyWidth + 1);
|
|
|
|
bool defined() const { return !!createConstructor_; }
|
|
|
|
bool delegated() const {
|
|
return (flags & IsDelegated);
|
|
}
|
|
|
|
bool dependent() const {
|
|
MOZ_ASSERT(defined());
|
|
return (flags & ParentKeyMask);
|
|
}
|
|
|
|
JSProtoKey parentKey() const {
|
|
static_assert(JSProto_Null == 0, "zeroed key must be null");
|
|
return JSProtoKey(flags & ParentKeyMask);
|
|
}
|
|
|
|
bool shouldDefineConstructor() const {
|
|
MOZ_ASSERT(defined());
|
|
return !(flags & DontDefineConstructor);
|
|
}
|
|
|
|
const ClassSpec* delegatedClassSpec() const {
|
|
MOZ_ASSERT(delegated());
|
|
return reinterpret_cast<ClassSpec*>(createConstructor_);
|
|
}
|
|
|
|
ClassObjectCreationOp createConstructorHook() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->createConstructorHook();
|
|
return createConstructor_;
|
|
}
|
|
ClassObjectCreationOp createPrototypeHook() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->createPrototypeHook();
|
|
return createPrototype_;
|
|
}
|
|
const JSFunctionSpec* constructorFunctions() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->constructorFunctions();
|
|
return constructorFunctions_;
|
|
}
|
|
const JSPropertySpec* constructorProperties() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->constructorProperties();
|
|
return constructorProperties_;
|
|
}
|
|
const JSFunctionSpec* prototypeFunctions() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->prototypeFunctions();
|
|
return prototypeFunctions_;
|
|
}
|
|
const JSPropertySpec* prototypeProperties() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->prototypeProperties();
|
|
return prototypeProperties_;
|
|
}
|
|
FinishClassInitOp finishInitHook() const {
|
|
if (delegated())
|
|
return delegatedClassSpec()->finishInitHook();
|
|
return finishInit_;
|
|
}
|
|
};
|
|
|
|
struct ClassExtension
|
|
{
|
|
/**
|
|
* If an object is used as a key in a weakmap, it may be desirable for the
|
|
* garbage collector to keep that object around longer than it otherwise
|
|
* would. A common case is when the key is a wrapper around an object in
|
|
* another compartment, and we want to avoid collecting the wrapper (and
|
|
* removing the weakmap entry) as long as the wrapped object is alive. In
|
|
* that case, the wrapped object is returned by the wrapper's
|
|
* weakmapKeyDelegateOp hook. As long as the wrapper is used as a weakmap
|
|
* key, it will not be collected (and remain in the weakmap) until the
|
|
* wrapped object is collected.
|
|
*/
|
|
JSWeakmapKeyDelegateOp weakmapKeyDelegateOp;
|
|
|
|
/**
|
|
* Optional hook called when an object is moved by a compacting GC.
|
|
*
|
|
* There may exist weak pointers to an object that are not traced through
|
|
* when the normal trace APIs are used, for example objects in the wrapper
|
|
* cache. This hook allows these pointers to be updated.
|
|
*
|
|
* Note that this hook can be called before JS_NewObject() returns if a GC
|
|
* is triggered during construction of the object. This can happen for
|
|
* global objects for example.
|
|
*/
|
|
JSObjectMovedOp objectMovedOp;
|
|
};
|
|
|
|
inline ClassObjectCreationOp DELEGATED_CLASSSPEC(const ClassSpec* spec) {
|
|
return reinterpret_cast<ClassObjectCreationOp>(const_cast<ClassSpec*>(spec));
|
|
}
|
|
|
|
#define JS_NULL_CLASS_SPEC nullptr
|
|
#define JS_NULL_CLASS_EXT nullptr
|
|
|
|
struct ObjectOps
|
|
{
|
|
LookupPropertyOp lookupProperty;
|
|
DefinePropertyOp defineProperty;
|
|
HasPropertyOp hasProperty;
|
|
GetPropertyOp getProperty;
|
|
SetPropertyOp setProperty;
|
|
GetOwnPropertyOp getOwnPropertyDescriptor;
|
|
DeletePropertyOp deleteProperty;
|
|
WatchOp watch;
|
|
UnwatchOp unwatch;
|
|
GetElementsOp getElements;
|
|
JSNewEnumerateOp enumerate;
|
|
JSFunToStringOp funToString;
|
|
};
|
|
|
|
#define JS_NULL_OBJECT_OPS nullptr
|
|
|
|
} // namespace js
|
|
|
|
// Classes, objects, and properties.
|
|
|
|
typedef void (*JSClassInternal)();
|
|
|
|
struct JSClassOps
|
|
{
|
|
/* Function pointer members (may be null). */
|
|
JSAddPropertyOp addProperty;
|
|
JSDeletePropertyOp delProperty;
|
|
JSGetterOp getProperty;
|
|
JSSetterOp setProperty;
|
|
JSEnumerateOp enumerate;
|
|
JSResolveOp resolve;
|
|
JSMayResolveOp mayResolve;
|
|
JSFinalizeOp finalize;
|
|
JSNative call;
|
|
JSHasInstanceOp hasInstance;
|
|
JSNative construct;
|
|
JSTraceOp trace;
|
|
};
|
|
|
|
#define JS_NULL_CLASS_OPS nullptr
|
|
|
|
struct JSClass {
|
|
JS_CLASS_MEMBERS(JSClassOps, JSFreeOp);
|
|
|
|
void* reserved[3];
|
|
};
|
|
|
|
#define JSCLASS_HAS_PRIVATE (1<<0) // objects have private slot
|
|
#define JSCLASS_DELAY_METADATA_BUILDER (1<<1) // class's initialization code
|
|
// will call
|
|
// SetNewObjectMetadata itself
|
|
#define JSCLASS_IS_WRAPPED_NATIVE (1<<2) // class is an XPCWrappedNative.
|
|
// WeakMaps use this to override
|
|
// the wrapper disposal
|
|
// mechanism.
|
|
#define JSCLASS_PRIVATE_IS_NSISUPPORTS (1<<3) // private is (nsISupports*)
|
|
#define JSCLASS_IS_DOMJSCLASS (1<<4) // objects are DOM
|
|
#define JSCLASS_HAS_XRAYED_CONSTRUCTOR (1<<5) // if wrapped by an xray
|
|
// wrapper, the builtin
|
|
// class's constructor won't
|
|
// be unwrapped and invoked.
|
|
// Instead, the constructor is
|
|
// resolved in the caller's
|
|
// compartment and invoked
|
|
// with a wrapped newTarget.
|
|
// The constructor has to
|
|
// detect and handle this
|
|
// situation.
|
|
// See PromiseConstructor for
|
|
// details.
|
|
#define JSCLASS_EMULATES_UNDEFINED (1<<6) // objects of this class act
|
|
// like the value undefined,
|
|
// in some contexts
|
|
#define JSCLASS_USERBIT1 (1<<7) // Reserved for embeddings.
|
|
|
|
// To reserve slots fetched and stored via JS_Get/SetReservedSlot, bitwise-or
|
|
// JSCLASS_HAS_RESERVED_SLOTS(n) into the initializer for JSClass.flags, where
|
|
// n is a constant in [1, 255]. Reserved slots are indexed from 0 to n-1.
|
|
#define JSCLASS_RESERVED_SLOTS_SHIFT 8 // room for 8 flags below */
|
|
#define JSCLASS_RESERVED_SLOTS_WIDTH 8 // and 16 above this field */
|
|
#define JSCLASS_RESERVED_SLOTS_MASK JS_BITMASK(JSCLASS_RESERVED_SLOTS_WIDTH)
|
|
#define JSCLASS_HAS_RESERVED_SLOTS(n) (((n) & JSCLASS_RESERVED_SLOTS_MASK) \
|
|
<< JSCLASS_RESERVED_SLOTS_SHIFT)
|
|
#define JSCLASS_RESERVED_SLOTS(clasp) (((clasp)->flags \
|
|
>> JSCLASS_RESERVED_SLOTS_SHIFT) \
|
|
& JSCLASS_RESERVED_SLOTS_MASK)
|
|
|
|
#define JSCLASS_HIGH_FLAGS_SHIFT (JSCLASS_RESERVED_SLOTS_SHIFT + \
|
|
JSCLASS_RESERVED_SLOTS_WIDTH)
|
|
|
|
#define JSCLASS_IS_ANONYMOUS (1<<(JSCLASS_HIGH_FLAGS_SHIFT+0))
|
|
#define JSCLASS_IS_GLOBAL (1<<(JSCLASS_HIGH_FLAGS_SHIFT+1))
|
|
#define JSCLASS_INTERNAL_FLAG2 (1<<(JSCLASS_HIGH_FLAGS_SHIFT+2))
|
|
#define JSCLASS_INTERNAL_FLAG3 (1<<(JSCLASS_HIGH_FLAGS_SHIFT+3))
|
|
|
|
#define JSCLASS_IS_PROXY (1<<(JSCLASS_HIGH_FLAGS_SHIFT+4))
|
|
|
|
#define JSCLASS_SKIP_NURSERY_FINALIZE (1<<(JSCLASS_HIGH_FLAGS_SHIFT+5))
|
|
|
|
// Reserved for embeddings.
|
|
#define JSCLASS_USERBIT2 (1<<(JSCLASS_HIGH_FLAGS_SHIFT+6))
|
|
#define JSCLASS_USERBIT3 (1<<(JSCLASS_HIGH_FLAGS_SHIFT+7))
|
|
|
|
#define JSCLASS_BACKGROUND_FINALIZE (1<<(JSCLASS_HIGH_FLAGS_SHIFT+8))
|
|
|
|
// Bits 26 through 31 are reserved for the CACHED_PROTO_KEY mechanism, see
|
|
// below.
|
|
|
|
// ECMA-262 requires that most constructors used internally create objects
|
|
// with "the original Foo.prototype value" as their [[Prototype]] (__proto__)
|
|
// member initial value. The "original ... value" verbiage is there because
|
|
// in ECMA-262, global properties naming class objects are read/write and
|
|
// deleteable, for the most part.
|
|
//
|
|
// Implementing this efficiently requires that global objects have classes
|
|
// with the following flags. Failure to use JSCLASS_GLOBAL_FLAGS was
|
|
// previously allowed, but is now an ES5 violation and thus unsupported.
|
|
//
|
|
// JSCLASS_GLOBAL_APPLICATION_SLOTS is the number of slots reserved at
|
|
// the beginning of every global object's slots for use by the
|
|
// application.
|
|
#define JSCLASS_GLOBAL_APPLICATION_SLOTS 5
|
|
#define JSCLASS_GLOBAL_SLOT_COUNT \
|
|
(JSCLASS_GLOBAL_APPLICATION_SLOTS + JSProto_LIMIT * 3 + 36)
|
|
#define JSCLASS_GLOBAL_FLAGS_WITH_SLOTS(n) \
|
|
(JSCLASS_IS_GLOBAL | JSCLASS_HAS_RESERVED_SLOTS(JSCLASS_GLOBAL_SLOT_COUNT + (n)))
|
|
#define JSCLASS_GLOBAL_FLAGS \
|
|
JSCLASS_GLOBAL_FLAGS_WITH_SLOTS(0)
|
|
#define JSCLASS_HAS_GLOBAL_FLAG_AND_SLOTS(clasp) \
|
|
(((clasp)->flags & JSCLASS_IS_GLOBAL) \
|
|
&& JSCLASS_RESERVED_SLOTS(clasp) >= JSCLASS_GLOBAL_SLOT_COUNT)
|
|
|
|
// Fast access to the original value of each standard class's prototype.
|
|
#define JSCLASS_CACHED_PROTO_SHIFT (JSCLASS_HIGH_FLAGS_SHIFT + 10)
|
|
#define JSCLASS_CACHED_PROTO_MASK JS_BITMASK(js::JSCLASS_CACHED_PROTO_WIDTH)
|
|
#define JSCLASS_HAS_CACHED_PROTO(key) (uint32_t(key) << JSCLASS_CACHED_PROTO_SHIFT)
|
|
#define JSCLASS_CACHED_PROTO_KEY(clasp) ((JSProtoKey) \
|
|
(((clasp)->flags \
|
|
>> JSCLASS_CACHED_PROTO_SHIFT) \
|
|
& JSCLASS_CACHED_PROTO_MASK))
|
|
|
|
// Initializer for unused members of statically initialized JSClass structs.
|
|
#define JSCLASS_NO_INTERNAL_MEMBERS {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
|
|
#define JSCLASS_NO_OPTIONAL_MEMBERS 0,0,0,0,0,JSCLASS_NO_INTERNAL_MEMBERS
|
|
|
|
namespace js {
|
|
|
|
struct Class
|
|
{
|
|
JS_CLASS_MEMBERS(js::ClassOps, FreeOp);
|
|
const ClassSpec* spec;
|
|
const ClassExtension* ext;
|
|
const ObjectOps* oOps;
|
|
|
|
/*
|
|
* Objects of this class aren't native objects. They don't have Shapes that
|
|
* describe their properties and layout. Classes using this flag must
|
|
* provide their own property behavior, either by being proxy classes (do
|
|
* this) or by overriding all the ObjectOps except getElements, watch and
|
|
* unwatch (don't do this).
|
|
*/
|
|
static const uint32_t NON_NATIVE = JSCLASS_INTERNAL_FLAG2;
|
|
|
|
bool isNative() const {
|
|
return !(flags & NON_NATIVE);
|
|
}
|
|
|
|
bool hasPrivate() const {
|
|
return !!(flags & JSCLASS_HAS_PRIVATE);
|
|
}
|
|
|
|
bool emulatesUndefined() const {
|
|
return flags & JSCLASS_EMULATES_UNDEFINED;
|
|
}
|
|
|
|
bool isJSFunction() const {
|
|
return this == js::FunctionClassPtr;
|
|
}
|
|
|
|
bool nonProxyCallable() const {
|
|
MOZ_ASSERT(!isProxy());
|
|
return isJSFunction() || getCall();
|
|
}
|
|
|
|
bool isProxy() const {
|
|
return flags & JSCLASS_IS_PROXY;
|
|
}
|
|
|
|
bool isDOMClass() const {
|
|
return flags & JSCLASS_IS_DOMJSCLASS;
|
|
}
|
|
|
|
bool shouldDelayMetadataBuilder() const {
|
|
return flags & JSCLASS_DELAY_METADATA_BUILDER;
|
|
}
|
|
|
|
bool isWrappedNative() const {
|
|
return flags & JSCLASS_IS_WRAPPED_NATIVE;
|
|
}
|
|
|
|
static size_t offsetOfFlags() { return offsetof(Class, flags); }
|
|
|
|
bool specDefined() const { return spec ? spec->defined() : false; }
|
|
bool specDependent() const { return spec ? spec->dependent() : false; }
|
|
JSProtoKey specParentKey() const { return spec ? spec->parentKey() : JSProto_Null; }
|
|
bool specShouldDefineConstructor()
|
|
const { return spec ? spec->shouldDefineConstructor() : true; }
|
|
ClassObjectCreationOp specCreateConstructorHook()
|
|
const { return spec ? spec->createConstructorHook() : nullptr; }
|
|
ClassObjectCreationOp specCreatePrototypeHook()
|
|
const { return spec ? spec->createPrototypeHook() : nullptr; }
|
|
const JSFunctionSpec* specConstructorFunctions()
|
|
const { return spec ? spec->constructorFunctions() : nullptr; }
|
|
const JSPropertySpec* specConstructorProperties()
|
|
const { return spec ? spec->constructorProperties() : nullptr; }
|
|
const JSFunctionSpec* specPrototypeFunctions()
|
|
const { return spec ? spec->prototypeFunctions() : nullptr; }
|
|
const JSPropertySpec* specPrototypeProperties()
|
|
const { return spec ? spec->prototypeProperties() : nullptr; }
|
|
FinishClassInitOp specFinishInitHook()
|
|
const { return spec ? spec->finishInitHook() : nullptr; }
|
|
|
|
JSWeakmapKeyDelegateOp extWeakmapKeyDelegateOp()
|
|
const { return ext ? ext->weakmapKeyDelegateOp : nullptr; }
|
|
JSObjectMovedOp extObjectMovedOp()
|
|
const { return ext ? ext->objectMovedOp : nullptr; }
|
|
|
|
LookupPropertyOp getOpsLookupProperty() const { return oOps ? oOps->lookupProperty : nullptr; }
|
|
DefinePropertyOp getOpsDefineProperty() const { return oOps ? oOps->defineProperty : nullptr; }
|
|
HasPropertyOp getOpsHasProperty() const { return oOps ? oOps->hasProperty : nullptr; }
|
|
GetPropertyOp getOpsGetProperty() const { return oOps ? oOps->getProperty : nullptr; }
|
|
SetPropertyOp getOpsSetProperty() const { return oOps ? oOps->setProperty : nullptr; }
|
|
GetOwnPropertyOp getOpsGetOwnPropertyDescriptor()
|
|
const { return oOps ? oOps->getOwnPropertyDescriptor
|
|
: nullptr; }
|
|
DeletePropertyOp getOpsDeleteProperty() const { return oOps ? oOps->deleteProperty : nullptr; }
|
|
WatchOp getOpsWatch() const { return oOps ? oOps->watch : nullptr; }
|
|
UnwatchOp getOpsUnwatch() const { return oOps ? oOps->unwatch : nullptr; }
|
|
GetElementsOp getOpsGetElements() const { return oOps ? oOps->getElements : nullptr; }
|
|
JSNewEnumerateOp getOpsEnumerate() const { return oOps ? oOps->enumerate : nullptr; }
|
|
JSFunToStringOp getOpsFunToString() const { return oOps ? oOps->funToString : nullptr; }
|
|
};
|
|
|
|
static_assert(offsetof(JSClassOps, addProperty) == offsetof(ClassOps, addProperty),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, delProperty) == offsetof(ClassOps, delProperty),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, getProperty) == offsetof(ClassOps, getProperty),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, setProperty) == offsetof(ClassOps, setProperty),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, enumerate) == offsetof(ClassOps, enumerate),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, resolve) == offsetof(ClassOps, resolve),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, mayResolve) == offsetof(ClassOps, mayResolve),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, finalize) == offsetof(ClassOps, finalize),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, call) == offsetof(ClassOps, call),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, construct) == offsetof(ClassOps, construct),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, hasInstance) == offsetof(ClassOps, hasInstance),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(offsetof(JSClassOps, trace) == offsetof(ClassOps, trace),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
static_assert(sizeof(JSClassOps) == sizeof(ClassOps),
|
|
"ClassOps and JSClassOps must be consistent");
|
|
|
|
static_assert(offsetof(JSClass, name) == offsetof(Class, name),
|
|
"Class and JSClass must be consistent");
|
|
static_assert(offsetof(JSClass, flags) == offsetof(Class, flags),
|
|
"Class and JSClass must be consistent");
|
|
static_assert(offsetof(JSClass, cOps) == offsetof(Class, cOps),
|
|
"Class and JSClass must be consistent");
|
|
static_assert(sizeof(JSClass) == sizeof(Class),
|
|
"Class and JSClass must be consistent");
|
|
|
|
static MOZ_ALWAYS_INLINE const JSClass*
|
|
Jsvalify(const Class* c)
|
|
{
|
|
return (const JSClass*)c;
|
|
}
|
|
|
|
static MOZ_ALWAYS_INLINE const Class*
|
|
Valueify(const JSClass* c)
|
|
{
|
|
return (const Class*)c;
|
|
}
|
|
|
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/**
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|
* Enumeration describing possible values of the [[Class]] internal property
|
|
* value of objects.
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*/
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enum class ESClass {
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Object,
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Array,
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Number,
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String,
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Boolean,
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RegExp,
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ArrayBuffer,
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SharedArrayBuffer,
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|
Date,
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Set,
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Map,
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Promise,
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MapIterator,
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SetIterator,
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|
Arguments,
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|
Error,
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|
|
/** None of the above. */
|
|
Other
|
|
};
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|
|
/* Fills |vp| with the unboxed value for boxed types, or undefined otherwise. */
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|
bool
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|
Unbox(JSContext* cx, JS::HandleObject obj, JS::MutableHandleValue vp);
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|
|
|
#ifdef DEBUG
|
|
JS_FRIEND_API(bool)
|
|
HasObjectMovedOp(JSObject* obj);
|
|
#endif
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|
|
|
} /* namespace js */
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|
|
|
#endif /* js_Class_h */
|