mirror of
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ac969048da
This is a case where our incremental marking verification is too strict. It's complaining that we're marking something gray when non-incrmental marking would not have marked it at all. This happens because the prebarrier is marking a weakmap key black and the map itself is gray, resulting in the map entry's value being marked gray. This case is OK because the value is actually unreachable. The opposite case where incremental marking marks something gray that non-incremental marking would have marked black is not OK and could lead to the cycle collector thinking something is part of a garbage cycle when it's actually live. But that can't happen here because the cycle collector won't be able to find the gray value in the first place. Differential Revision: https://phabricator.services.mozilla.com/D215786
783 lines
31 KiB
C++
783 lines
31 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* vim: set ts=8 sts=2 et sw=2 tw=80:
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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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#ifndef js_Proxy_h
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#define js_Proxy_h
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#include "mozilla/Maybe.h"
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#include "jstypes.h" // for JS_PUBLIC_API, JS_PUBLIC_DATA
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#include "js/Array.h" // JS::IsArrayAnswer
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#include "js/CallNonGenericMethod.h"
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#include "js/Class.h"
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#include "js/HeapAPI.h" // for ObjectIsMarkedBlack
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#include "js/Id.h" // for jsid
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#include "js/Object.h" // JS::GetClass
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#include "js/RootingAPI.h" // for Handle, MutableHandle (ptr only)
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#include "js/shadow/Object.h" // JS::shadow::Object
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#include "js/TypeDecls.h" // for HandleObject, HandleId, HandleValue, MutableHandleIdVector, MutableHandleValue, MutableHand...
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#include "js/Value.h" // for Value, AssertValueIsNotGray, UndefinedValue, ObjectOrNullValue
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namespace js {
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class RegExpShared;
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class JS_PUBLIC_API Wrapper;
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/*
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* [SMDOC] Proxy Objects
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*
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* A proxy is a JSObject with highly customizable behavior. ES6 specifies a
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* single kind of proxy, but the customization mechanisms we use to implement
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* ES6 Proxy objects are also useful wherever an object with weird behavior is
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* wanted. Proxies are used to implement:
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*
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* - the scope objects used by the Debugger's frame.eval() method
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* (see js::GetDebugEnvironment)
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*
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* - the khuey hack, whereby a whole compartment can be blown away
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* even if other compartments hold references to objects in it
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* (see js::NukeCrossCompartmentWrappers)
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*
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* - XPConnect security wrappers, which protect chrome from malicious content
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* (js/xpconnect/wrappers)
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*
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* - DOM objects with special property behavior, like named getters
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* (dom/bindings/Codegen.py generates these proxies from WebIDL)
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*
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* ### Proxies and internal methods
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*
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* ES2019 specifies 13 internal methods. The runtime semantics of just about
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* everything a script can do to an object is specified in terms of these
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* internal methods. For example:
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*
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* JS code ES6 internal method that gets called
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* --------------------------- --------------------------------
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* obj.prop obj.[[Get]](obj, "prop")
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* "prop" in obj obj.[[HasProperty]]("prop")
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* new obj() obj.[[Construct]](<empty argument List>)
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*
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* With regard to the implementation of these internal methods, there are three
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* very different kinds of object in SpiderMonkey.
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*
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* 1. Native objects cover most objects and contain both internal slots and
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* properties. JSClassOps and ObjectOps may be used to override certain
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* default behaviors.
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*
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* 2. Proxy objects are composed of internal slots and a ProxyHandler. The
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* handler contains C++ methods that can implement these standard (and
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* non-standard) internal methods. JSClassOps and ObjectOps for the base
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* ProxyObject invoke the handler methods as appropriate.
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*
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* 3. Objects with custom layouts like TypedObjects. These rely on JSClassOps
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* and ObjectOps to implement internal methods.
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*
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* Native objects with custom JSClassOps / ObjectOps are used when the object
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* behaves very similar to a normal object such as the ArrayObject and it's
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* length property. Most usages wrapping a C++ or other type should prefer
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* using a Proxy. Using the proxy approach makes it much easier to create an
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* ECMAScript and JIT compatible object, particularly if using an appropriate
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* base class.
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*
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* Just about anything you do to a proxy will end up going through a C++
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* virtual method call. Possibly several. There's no reason the JITs and ICs
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* can't specialize for particular proxies, based on the handler; but currently
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* we don't do much of this, so the virtual method overhead typically is
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* actually incurred.
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*
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* ### The proxy handler hierarchy
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*
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* A major use case for proxies is to forward each internal method call to
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* another object, known as its target. The target can be an arbitrary JS
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* object. Not every proxy has the notion of a target, however.
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*
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* To minimize code duplication, a set of abstract proxy handler classes is
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* provided, from which other handlers may inherit. These abstract classes are
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* organized in the following hierarchy:
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*
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* BaseProxyHandler
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* | |
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* | NurseryAllocableProxyHandler
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* | // allocated in the nursery; disallows
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* | // overriding finalize method
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* |
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* ForwardingProxyHandler // has a target and forwards internal methods
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* |
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* Wrapper // can be unwrapped to reveal target
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* | // (see js::CheckedUnwrap)
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* |
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* CrossCompartmentWrapper // target is in another compartment;
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* // implements membrane between compartments
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*
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* Example: Some DOM objects (including all the arraylike DOM objects) are
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* implemented as proxies. Since these objects don't need to forward operations
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* to any underlying JS object, BaseDOMProxyHandler directly subclasses
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* BaseProxyHandler.
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*
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* Gecko's security wrappers are examples of cross-compartment wrappers.
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*
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* ### Proxy prototype chains
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*
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* While most ECMAScript internal methods are handled by simply calling the
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* handler method, the [[GetPrototypeOf]] / [[SetPrototypeOf]] behaviors may
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* follow one of two models:
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*
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* 1. A concrete prototype object (or null) is passed to object construction
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* and ordinary prototype read and write applies. The prototype-related
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* handler hooks are never called in this case. The [[Prototype]] slot is
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* used to store the current prototype value.
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*
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* 2. TaggedProto::LazyProto is passed to NewProxyObject (or the
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* ProxyOptions::lazyProto flag is set). Each read or write of the
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* prototype will invoke the handler. This dynamic prototype behavior may
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* be useful for wrapper-like objects. If this mode is used the
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* getPrototype handler at a minimum must be implemented.
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*
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* NOTE: In this mode the [[Prototype]] internal slot is unavailable and
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* must be simulated if needed. This is non-standard, but an
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* appropriate handler can hide this implementation detail.
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*
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* One subtlety here is that ECMAScript has a notion of "ordinary" prototypes.
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* An object that doesn't override [[GetPrototypeOf]] is considered to have an
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* ordinary prototype. The getPrototypeIfOrdinary handler must be implemented
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* by you or your base class. Typically model 1 will be considered "ordinary"
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* and model 2 will not.
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*/
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/*
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* BaseProxyHandler is the most generic kind of proxy handler. It does not make
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* any assumptions about the target. Consequently, it does not provide any
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* default implementation for most methods. As a convenience, a few high-level
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* methods, like get() and set(), are given default implementations that work by
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* calling the low-level methods, like getOwnPropertyDescriptor().
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*
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* Important: If you add a method here, you should probably also add a
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* Proxy::foo entry point with an AutoEnterPolicy. If you don't, you need an
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* explicit override for the method in SecurityWrapper. See bug 945826 comment
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* 0.
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*/
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class JS_PUBLIC_API BaseProxyHandler {
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/*
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* Sometimes it's desirable to designate groups of proxy handlers as
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* "similar". For this, we use the notion of a "family": A consumer-provided
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* opaque pointer that designates the larger group to which this proxy
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* belongs.
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*
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* If it will never be important to differentiate this proxy from others as
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* part of a distinct group, nullptr may be used instead.
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*/
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const void* mFamily;
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/*
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* Proxy handlers can use mHasPrototype to request the following special
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* treatment from the JS engine:
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*
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* - When mHasPrototype is true, the engine never calls these methods:
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* has, set, enumerate, iterate. Instead, for these operations,
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* it calls the "own" methods like getOwnPropertyDescriptor, hasOwn,
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* defineProperty, getOwnEnumerablePropertyKeys, etc.,
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* and consults the prototype chain if needed.
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*
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* - When mHasPrototype is true, the engine calls handler->get() only if
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* handler->hasOwn() says an own property exists on the proxy. If not,
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* it consults the prototype chain.
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*
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* This is useful because it frees the ProxyHandler from having to implement
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* any behavior having to do with the prototype chain.
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*/
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bool mHasPrototype;
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/*
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* All proxies indicate whether they have any sort of interesting security
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* policy that might prevent the caller from doing something it wants to
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* the object. In the case of wrappers, this distinction is used to
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* determine whether the caller may strip off the wrapper if it so desires.
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*/
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bool mHasSecurityPolicy;
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public:
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explicit constexpr BaseProxyHandler(const void* aFamily,
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bool aHasPrototype = false,
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bool aHasSecurityPolicy = false)
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: mFamily(aFamily),
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mHasPrototype(aHasPrototype),
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mHasSecurityPolicy(aHasSecurityPolicy) {}
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bool hasPrototype() const { return mHasPrototype; }
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bool hasSecurityPolicy() const { return mHasSecurityPolicy; }
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inline const void* family() const { return mFamily; }
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static size_t offsetOfFamily() { return offsetof(BaseProxyHandler, mFamily); }
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virtual bool finalizeInBackground(const JS::Value& priv) const {
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/*
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* Called on creation of a proxy to determine whether its finalize
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* method can be finalized on the background thread.
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*/
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return true;
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}
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virtual bool canNurseryAllocate() const {
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/*
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* Nursery allocation is allowed if and only if it is safe to not
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* run |finalize| when the ProxyObject dies.
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*/
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return false;
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}
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/* Policy enforcement methods.
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*
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* enter() allows the policy to specify whether the caller may perform |act|
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* on the proxy's |id| property. In the case when |act| is CALL, |id| is
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* generally JS::PropertyKey::isVoid. The |mayThrow| parameter indicates
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* whether a handler that wants to throw custom exceptions when denying
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* should do so or not.
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*
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* The |act| parameter to enter() specifies the action being performed.
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* If |bp| is false, the method suggests that the caller throw (though it
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* may still decide to squelch the error).
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*
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* We make these OR-able so that assertEnteredPolicy can pass a union of them.
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* For example, get{,Own}PropertyDescriptor is invoked by calls to ::get()
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* ::set(), in addition to being invoked on its own, so there are several
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* valid Actions that could have been entered.
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*/
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typedef uint32_t Action;
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enum {
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NONE = 0x00,
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GET = 0x01,
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SET = 0x02,
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CALL = 0x04,
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ENUMERATE = 0x08,
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GET_PROPERTY_DESCRIPTOR = 0x10
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};
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virtual bool enter(JSContext* cx, JS::HandleObject wrapper, JS::HandleId id,
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Action act, bool mayThrow, bool* bp) const;
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/* Standard internal methods. */
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virtual bool getOwnPropertyDescriptor(
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JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
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JS::MutableHandle<mozilla::Maybe<JS::PropertyDescriptor>> desc) const = 0;
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virtual bool defineProperty(JSContext* cx, JS::HandleObject proxy,
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JS::HandleId id,
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JS::Handle<JS::PropertyDescriptor> desc,
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JS::ObjectOpResult& result) const = 0;
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virtual bool ownPropertyKeys(JSContext* cx, JS::HandleObject proxy,
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JS::MutableHandleIdVector props) const = 0;
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virtual bool delete_(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
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JS::ObjectOpResult& result) const = 0;
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/*
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* These methods are standard, but the engine does not normally call them.
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* They're opt-in. See "Proxy prototype chains" above.
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*
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* getPrototype() crashes if called. setPrototype() throws a TypeError.
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*/
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virtual bool getPrototype(JSContext* cx, JS::HandleObject proxy,
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JS::MutableHandleObject protop) const;
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virtual bool setPrototype(JSContext* cx, JS::HandleObject proxy,
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JS::HandleObject proto,
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JS::ObjectOpResult& result) const;
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/* Non-standard but conceptual kin to {g,s}etPrototype, so these live here. */
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virtual bool getPrototypeIfOrdinary(JSContext* cx, JS::HandleObject proxy,
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bool* isOrdinary,
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JS::MutableHandleObject protop) const = 0;
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virtual bool setImmutablePrototype(JSContext* cx, JS::HandleObject proxy,
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bool* succeeded) const;
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virtual bool preventExtensions(JSContext* cx, JS::HandleObject proxy,
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JS::ObjectOpResult& result) const = 0;
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virtual bool isExtensible(JSContext* cx, JS::HandleObject proxy,
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bool* extensible) const = 0;
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/*
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* These standard internal methods are implemented, as a convenience, so
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* that ProxyHandler subclasses don't have to provide every single method.
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*
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* The base-class implementations work by calling getOwnPropertyDescriptor()
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* and going up the [[Prototype]] chain if necessary. The algorithm for this
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* follows what is defined for Ordinary Objects in the ES spec.
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* They do not follow any standard. When in doubt, override them.
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*/
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virtual bool has(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
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bool* bp) const;
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virtual bool get(JSContext* cx, JS::HandleObject proxy,
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JS::HandleValue receiver, JS::HandleId id,
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JS::MutableHandleValue vp) const;
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virtual bool set(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
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JS::HandleValue v, JS::HandleValue receiver,
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JS::ObjectOpResult& result) const;
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// Use the ProxyExpando object for private fields, rather than taking the
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// normal get/set/defineField paths.
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virtual bool useProxyExpandoObjectForPrivateFields() const { return true; }
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// For some exotic objects (WindowProxy, Location), we want to be able to
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// throw rather than allow private fields on these objects.
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//
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// As a simplfying assumption, if throwOnPrivateFields returns true,
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// we should also return true to useProxyExpandoObjectForPrivateFields.
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virtual bool throwOnPrivateField() const { return false; }
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/*
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* [[Call]] and [[Construct]] are standard internal methods but according
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* to the spec, they are not present on every object.
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*
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* SpiderMonkey never calls a proxy's call()/construct() internal method
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* unless isCallable()/isConstructor() returns true for that proxy.
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*
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* BaseProxyHandler::isCallable()/isConstructor() always return false, and
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* BaseProxyHandler::call()/construct() crash if called. So if you're
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* creating a kind of that is never callable, you don't have to override
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* anything, but otherwise you probably want to override all four.
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*/
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virtual bool call(JSContext* cx, JS::HandleObject proxy,
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const JS::CallArgs& args) const;
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virtual bool construct(JSContext* cx, JS::HandleObject proxy,
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const JS::CallArgs& args) const;
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/* SpiderMonkey extensions. */
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virtual bool enumerate(JSContext* cx, JS::HandleObject proxy,
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JS::MutableHandleIdVector props) const;
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virtual bool hasOwn(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
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bool* bp) const;
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virtual bool getOwnEnumerablePropertyKeys(
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JSContext* cx, JS::HandleObject proxy,
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JS::MutableHandleIdVector props) const;
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virtual bool nativeCall(JSContext* cx, JS::IsAcceptableThis test,
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JS::NativeImpl impl, const JS::CallArgs& args) const;
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virtual bool getBuiltinClass(JSContext* cx, JS::HandleObject proxy,
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ESClass* cls) const;
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virtual bool isArray(JSContext* cx, JS::HandleObject proxy,
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JS::IsArrayAnswer* answer) const;
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virtual const char* className(JSContext* cx, JS::HandleObject proxy) const;
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virtual JSString* fun_toString(JSContext* cx, JS::HandleObject proxy,
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bool isToSource) const;
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virtual RegExpShared* regexp_toShared(JSContext* cx,
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JS::HandleObject proxy) const;
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virtual bool boxedValue_unbox(JSContext* cx, JS::HandleObject proxy,
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JS::MutableHandleValue vp) const;
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virtual void trace(JSTracer* trc, JSObject* proxy) const;
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virtual void finalize(JS::GCContext* gcx, JSObject* proxy) const;
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virtual size_t objectMoved(JSObject* proxy, JSObject* old) const;
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// Allow proxies, wrappers in particular, to specify callability at runtime.
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// Note: These do not take const JSObject*, but they do in spirit.
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// We are not prepared to do this, as there's little const correctness
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// in the external APIs that handle proxies.
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virtual bool isCallable(JSObject* obj) const;
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virtual bool isConstructor(JSObject* obj) const;
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virtual bool getElements(JSContext* cx, JS::HandleObject proxy,
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uint32_t begin, uint32_t end,
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ElementAdder* adder) const;
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virtual bool isScripted() const { return false; }
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};
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class JS_PUBLIC_API NurseryAllocableProxyHandler : public BaseProxyHandler {
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using BaseProxyHandler::BaseProxyHandler;
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// Don't allow overriding the default finalize method.
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void finalize(JS::GCContext* gcx, JSObject* proxy) const final {
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BaseProxyHandler::finalize(gcx, proxy);
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}
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// Can allocate in the nursery as long as we use the default finalize method.
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bool canNurseryAllocate() const override { return true; }
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};
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extern JS_PUBLIC_DATA const JSClass ProxyClass;
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inline bool IsProxy(const JSObject* obj) {
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return reinterpret_cast<const JS::shadow::Object*>(obj)->shape->isProxy();
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}
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namespace detail {
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// Proxy slot layout
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// -----------------
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//
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// Every proxy has a ProxyValueArray that contains the following Values:
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//
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// - The expando slot. This is used to hold private fields should they be
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// stamped into a non-forwarding proxy type.
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// - The private slot.
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// - The reserved slots. The number of slots is determined by the proxy's Class.
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//
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// Proxy objects store a pointer to the reserved slots (ProxyReservedSlots*).
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// The ProxyValueArray and the private slot can be accessed using
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// ProxyValueArray::fromReservedSlots or ProxyDataLayout::values.
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//
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// Storing a pointer to ProxyReservedSlots instead of ProxyValueArray has a
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// number of advantages. In particular, it means JS::GetReservedSlot and
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// JS::SetReservedSlot can be used with both proxies and native objects. This
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// works because the ProxyReservedSlots* pointer is stored where native objects
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// store their dynamic slots pointer.
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struct ProxyReservedSlots {
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JS::Value slots[1];
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static constexpr ptrdiff_t offsetOfPrivateSlot();
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static inline int offsetOfSlot(size_t slot) {
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return offsetof(ProxyReservedSlots, slots[0]) + slot * sizeof(JS::Value);
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}
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void init(size_t nreserved) {
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for (size_t i = 0; i < nreserved; i++) {
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slots[i] = JS::UndefinedValue();
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}
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}
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ProxyReservedSlots(const ProxyReservedSlots&) = delete;
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void operator=(const ProxyReservedSlots&) = delete;
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};
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struct ProxyValueArray {
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JS::Value expandoSlot;
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JS::Value privateSlot;
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ProxyReservedSlots reservedSlots;
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void init(size_t nreserved) {
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expandoSlot = JS::ObjectOrNullValue(nullptr);
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privateSlot = JS::UndefinedValue();
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reservedSlots.init(nreserved);
|
|
}
|
|
|
|
static MOZ_ALWAYS_INLINE ProxyValueArray* fromReservedSlots(
|
|
ProxyReservedSlots* slots) {
|
|
uintptr_t p = reinterpret_cast<uintptr_t>(slots);
|
|
return reinterpret_cast<ProxyValueArray*>(p - offsetOfReservedSlots());
|
|
}
|
|
static constexpr size_t offsetOfReservedSlots() {
|
|
return offsetof(ProxyValueArray, reservedSlots);
|
|
}
|
|
|
|
static size_t allocCount(size_t nreserved) {
|
|
static_assert(offsetOfReservedSlots() % sizeof(JS::Value) == 0);
|
|
return offsetOfReservedSlots() / sizeof(JS::Value) + nreserved;
|
|
}
|
|
static size_t sizeOf(size_t nreserved) {
|
|
return allocCount(nreserved) * sizeof(JS::Value);
|
|
}
|
|
|
|
ProxyValueArray(const ProxyValueArray&) = delete;
|
|
void operator=(const ProxyValueArray&) = delete;
|
|
};
|
|
|
|
/* static */
|
|
constexpr ptrdiff_t ProxyReservedSlots::offsetOfPrivateSlot() {
|
|
return -ptrdiff_t(ProxyValueArray::offsetOfReservedSlots()) +
|
|
offsetof(ProxyValueArray, privateSlot);
|
|
}
|
|
|
|
// All proxies share the same data layout. Following the object's shape, the
|
|
// proxy has a ProxyDataLayout structure with a pointer to an array of values
|
|
// and the proxy's handler. This is designed both so that proxies can be easily
|
|
// swapped with other objects (via RemapWrapper) and to mimic the layout of
|
|
// other objects (proxies and other objects have the same size) so that common
|
|
// code can access either type of object.
|
|
//
|
|
// See GetReservedOrProxyPrivateSlot below.
|
|
struct ProxyDataLayout {
|
|
ProxyReservedSlots* reservedSlots;
|
|
const BaseProxyHandler* handler;
|
|
|
|
MOZ_ALWAYS_INLINE ProxyValueArray* values() const {
|
|
return ProxyValueArray::fromReservedSlots(reservedSlots);
|
|
}
|
|
};
|
|
|
|
#ifdef JS_64BIT
|
|
constexpr uint32_t ProxyDataOffset = 1 * sizeof(void*);
|
|
#else
|
|
constexpr uint32_t ProxyDataOffset = 2 * sizeof(void*);
|
|
#endif
|
|
|
|
inline ProxyDataLayout* GetProxyDataLayout(JSObject* obj) {
|
|
MOZ_ASSERT(IsProxy(obj));
|
|
return reinterpret_cast<ProxyDataLayout*>(reinterpret_cast<uint8_t*>(obj) +
|
|
ProxyDataOffset);
|
|
}
|
|
|
|
inline const ProxyDataLayout* GetProxyDataLayout(const JSObject* obj) {
|
|
MOZ_ASSERT(IsProxy(obj));
|
|
return reinterpret_cast<const ProxyDataLayout*>(
|
|
reinterpret_cast<const uint8_t*>(obj) + ProxyDataOffset);
|
|
}
|
|
|
|
JS_PUBLIC_API void SetValueInProxy(JS::Value* slot, const JS::Value& value);
|
|
|
|
inline void SetProxyReservedSlotUnchecked(JSObject* obj, size_t n,
|
|
const JS::Value& extra) {
|
|
MOZ_ASSERT(n < JSCLASS_RESERVED_SLOTS(JS::GetClass(obj)));
|
|
|
|
JS::Value* vp = &GetProxyDataLayout(obj)->reservedSlots->slots[n];
|
|
|
|
// Trigger a barrier before writing the slot.
|
|
if (vp->isGCThing() || extra.isGCThing()) {
|
|
SetValueInProxy(vp, extra);
|
|
} else {
|
|
*vp = extra;
|
|
}
|
|
}
|
|
|
|
} // namespace detail
|
|
|
|
inline const BaseProxyHandler* GetProxyHandler(const JSObject* obj) {
|
|
return detail::GetProxyDataLayout(obj)->handler;
|
|
}
|
|
|
|
inline const JS::Value& GetProxyPrivate(const JSObject* obj) {
|
|
return detail::GetProxyDataLayout(obj)->values()->privateSlot;
|
|
}
|
|
|
|
inline const JS::Value& GetProxyExpando(const JSObject* obj) {
|
|
return detail::GetProxyDataLayout(obj)->values()->expandoSlot;
|
|
}
|
|
|
|
inline JSObject* GetProxyTargetObject(const JSObject* obj) {
|
|
return GetProxyPrivate(obj).toObjectOrNull();
|
|
}
|
|
|
|
inline const JS::Value& GetProxyReservedSlot(const JSObject* obj, size_t n) {
|
|
MOZ_ASSERT(n < JSCLASS_RESERVED_SLOTS(JS::GetClass(obj)));
|
|
return detail::GetProxyDataLayout(obj)->reservedSlots->slots[n];
|
|
}
|
|
|
|
inline void SetProxyHandler(JSObject* obj, const BaseProxyHandler* handler) {
|
|
detail::GetProxyDataLayout(obj)->handler = handler;
|
|
}
|
|
|
|
inline void SetProxyReservedSlot(JSObject* obj, size_t n,
|
|
const JS::Value& extra) {
|
|
#ifdef DEBUG
|
|
if (gc::detail::ObjectIsMarkedBlack(obj)) {
|
|
JS::AssertValueIsNotGray(extra);
|
|
}
|
|
#endif
|
|
|
|
detail::SetProxyReservedSlotUnchecked(obj, n, extra);
|
|
}
|
|
|
|
inline void SetProxyPrivate(JSObject* obj, const JS::Value& value) {
|
|
#ifdef DEBUG
|
|
JS::AssertObjectIsNotGray(obj);
|
|
JS::AssertValueIsNotGray(value);
|
|
#endif
|
|
|
|
JS::Value* vp = &detail::GetProxyDataLayout(obj)->values()->privateSlot;
|
|
|
|
// Trigger a barrier before writing the slot.
|
|
if (vp->isGCThing() || value.isGCThing()) {
|
|
detail::SetValueInProxy(vp, value);
|
|
} else {
|
|
*vp = value;
|
|
}
|
|
}
|
|
|
|
inline bool IsScriptedProxy(const JSObject* obj) {
|
|
return IsProxy(obj) && GetProxyHandler(obj)->isScripted();
|
|
}
|
|
|
|
class MOZ_STACK_CLASS ProxyOptions {
|
|
protected:
|
|
/* protected constructor for subclass */
|
|
explicit ProxyOptions(bool lazyProtoArg)
|
|
: lazyProto_(lazyProtoArg), clasp_(&ProxyClass) {}
|
|
|
|
public:
|
|
ProxyOptions() : ProxyOptions(false) {}
|
|
|
|
bool lazyProto() const { return lazyProto_; }
|
|
ProxyOptions& setLazyProto(bool flag) {
|
|
lazyProto_ = flag;
|
|
return *this;
|
|
}
|
|
|
|
const JSClass* clasp() const { return clasp_; }
|
|
ProxyOptions& setClass(const JSClass* claspArg) {
|
|
clasp_ = claspArg;
|
|
return *this;
|
|
}
|
|
|
|
private:
|
|
bool lazyProto_;
|
|
const JSClass* clasp_;
|
|
};
|
|
|
|
JS_PUBLIC_API JSObject* NewProxyObject(
|
|
JSContext* cx, const BaseProxyHandler* handler, JS::HandleValue priv,
|
|
JSObject* proto, const ProxyOptions& options = ProxyOptions());
|
|
|
|
JSObject* RenewProxyObject(JSContext* cx, JSObject* obj,
|
|
BaseProxyHandler* handler, const JS::Value& priv);
|
|
|
|
class JS_PUBLIC_API AutoEnterPolicy {
|
|
public:
|
|
typedef BaseProxyHandler::Action Action;
|
|
AutoEnterPolicy(JSContext* cx, const BaseProxyHandler* handler,
|
|
JS::HandleObject wrapper, JS::HandleId id, Action act,
|
|
bool mayThrow)
|
|
#ifdef JS_DEBUG
|
|
: context(nullptr)
|
|
#endif
|
|
{
|
|
allow = handler->hasSecurityPolicy()
|
|
? handler->enter(cx, wrapper, id, act, mayThrow, &rv)
|
|
: true;
|
|
recordEnter(cx, wrapper, id, act);
|
|
// We want to throw an exception if all of the following are true:
|
|
// * The policy disallowed access.
|
|
// * The policy set rv to false, indicating that we should throw.
|
|
// * The caller did not instruct us to ignore exceptions.
|
|
// * The policy did not throw itself.
|
|
if (!allow && !rv && mayThrow) {
|
|
reportErrorIfExceptionIsNotPending(cx, id);
|
|
}
|
|
}
|
|
|
|
virtual ~AutoEnterPolicy() { recordLeave(); }
|
|
inline bool allowed() { return allow; }
|
|
inline bool returnValue() {
|
|
MOZ_ASSERT(!allowed());
|
|
return rv;
|
|
}
|
|
|
|
protected:
|
|
// no-op constructor for subclass
|
|
AutoEnterPolicy()
|
|
#ifdef JS_DEBUG
|
|
: context(nullptr),
|
|
enteredAction(BaseProxyHandler::NONE)
|
|
#endif
|
|
{
|
|
}
|
|
void reportErrorIfExceptionIsNotPending(JSContext* cx, JS::HandleId id);
|
|
bool allow;
|
|
bool rv;
|
|
|
|
#ifdef JS_DEBUG
|
|
JSContext* context;
|
|
mozilla::Maybe<JS::HandleObject> enteredProxy;
|
|
mozilla::Maybe<JS::HandleId> enteredId;
|
|
Action enteredAction;
|
|
|
|
// NB: We explicitly don't track the entered action here, because sometimes
|
|
// set() methods do an implicit get() during their implementation, leading
|
|
// to spurious assertions.
|
|
AutoEnterPolicy* prev;
|
|
void recordEnter(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
|
|
Action act);
|
|
void recordLeave();
|
|
|
|
friend JS_PUBLIC_API void assertEnteredPolicy(JSContext* cx, JSObject* proxy,
|
|
jsid id, Action act);
|
|
#else
|
|
inline void recordEnter(JSContext* cx, JSObject* proxy, jsid id, Action act) {
|
|
}
|
|
inline void recordLeave() {}
|
|
#endif
|
|
|
|
private:
|
|
// This operator needs to be deleted explicitly, otherwise Visual C++ will
|
|
// create it automatically when it is part of the export JS API. In that
|
|
// case, compile would fail because HandleId is not allowed to be assigned
|
|
// and consequently instantiation of assign operator of mozilla::Maybe
|
|
// would fail. See bug 1325351 comment 16. Copy constructor is removed at
|
|
// the same time for consistency.
|
|
AutoEnterPolicy(const AutoEnterPolicy&) = delete;
|
|
AutoEnterPolicy& operator=(const AutoEnterPolicy&) = delete;
|
|
};
|
|
|
|
#ifdef JS_DEBUG
|
|
class JS_PUBLIC_API AutoWaivePolicy : public AutoEnterPolicy {
|
|
public:
|
|
AutoWaivePolicy(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
|
|
BaseProxyHandler::Action act) {
|
|
allow = true;
|
|
recordEnter(cx, proxy, id, act);
|
|
}
|
|
};
|
|
#else
|
|
class JS_PUBLIC_API AutoWaivePolicy {
|
|
public:
|
|
AutoWaivePolicy(JSContext* cx, JS::HandleObject proxy, JS::HandleId id,
|
|
BaseProxyHandler::Action act) {}
|
|
};
|
|
#endif
|
|
|
|
#ifdef JS_DEBUG
|
|
extern JS_PUBLIC_API void assertEnteredPolicy(JSContext* cx, JSObject* obj,
|
|
jsid id,
|
|
BaseProxyHandler::Action act);
|
|
#else
|
|
inline void assertEnteredPolicy(JSContext* cx, JSObject* obj, jsid id,
|
|
BaseProxyHandler::Action act) {}
|
|
#endif
|
|
|
|
extern JS_PUBLIC_DATA const JSClassOps ProxyClassOps;
|
|
extern JS_PUBLIC_DATA const js::ClassExtension ProxyClassExtension;
|
|
extern JS_PUBLIC_DATA const js::ObjectOps ProxyObjectOps;
|
|
|
|
template <unsigned Flags>
|
|
constexpr unsigned CheckProxyFlags() {
|
|
constexpr size_t reservedSlots =
|
|
(Flags >> JSCLASS_RESERVED_SLOTS_SHIFT) & JSCLASS_RESERVED_SLOTS_MASK;
|
|
|
|
// For now assert each Proxy Class has at least 1 reserved slot. This is
|
|
// not a hard requirement, but helps catch Classes that need an explicit
|
|
// JSCLASS_HAS_RESERVED_SLOTS since bug 1360523.
|
|
static_assert(reservedSlots > 0,
|
|
"Proxy Classes must have at least 1 reserved slot");
|
|
|
|
constexpr size_t numSlots =
|
|
offsetof(js::detail::ProxyValueArray, reservedSlots) / sizeof(JS::Value);
|
|
|
|
// ProxyValueArray must fit inline in the object, so assert the number of
|
|
// slots does not exceed MAX_FIXED_SLOTS.
|
|
static_assert(numSlots + reservedSlots <= JS::shadow::Object::MAX_FIXED_SLOTS,
|
|
"ProxyValueArray size must not exceed max JSObject size");
|
|
|
|
// Proxies must not have the JSCLASS_SKIP_NURSERY_FINALIZE flag set: they
|
|
// always have finalizers, and whether they can be nursery allocated is
|
|
// controlled by the canNurseryAllocate() method on the proxy handler.
|
|
static_assert(!(Flags & JSCLASS_SKIP_NURSERY_FINALIZE),
|
|
"Proxies must not use JSCLASS_SKIP_NURSERY_FINALIZE; use "
|
|
"the canNurseryAllocate() proxy handler method instead.");
|
|
return Flags;
|
|
}
|
|
|
|
#define PROXY_CLASS_DEF_WITH_CLASS_SPEC(name, flags, classSpec) \
|
|
{name, \
|
|
JSClass::NON_NATIVE | JSCLASS_IS_PROXY | JSCLASS_DELAY_METADATA_BUILDER | \
|
|
js::CheckProxyFlags<flags>(), \
|
|
&js::ProxyClassOps, \
|
|
classSpec, \
|
|
&js::ProxyClassExtension, \
|
|
&js::ProxyObjectOps}
|
|
|
|
#define PROXY_CLASS_DEF(name, flags) \
|
|
PROXY_CLASS_DEF_WITH_CLASS_SPEC(name, flags, JS_NULL_CLASS_SPEC)
|
|
|
|
// Converts a proxy into a DeadObjectProxy that will throw exceptions on all
|
|
// access. This will run the proxy's finalizer to perform clean-up before the
|
|
// conversion happens.
|
|
JS_PUBLIC_API void NukeNonCCWProxy(JSContext* cx, JS::HandleObject proxy);
|
|
|
|
// This is a variant of js::NukeNonCCWProxy() for CCWs. It should only be called
|
|
// on CCWs that have been removed from CCW tables.
|
|
JS_PUBLIC_API void NukeRemovedCrossCompartmentWrapper(JSContext* cx,
|
|
JSObject* wrapper);
|
|
|
|
} /* namespace js */
|
|
|
|
#endif /* js_Proxy_h */
|