| /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- |
| * vim: set ts=8 sts=4 et sw=4 tw=99: |
| * This Source Code Form is subject to the terms of the Mozilla Public |
| * License, v. 2.0. If a copy of the MPL was not distributed with this |
| * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| |
| #ifndef jsproxy_h |
| #define jsproxy_h |
| |
| #include "jsapi.h" |
| #include "jsfriendapi.h" |
| |
| namespace js { |
| |
| class JS_FRIEND_API(Wrapper); |
| |
| /* |
| * A proxy is a JSObject that implements generic behavior by providing custom |
| * implementations for each object trap. The implementation for each trap is |
| * provided by a C++ object stored on the proxy, known as its handler. |
| * |
| * A major use case for proxies is to forward each trap to another object, |
| * known as its target. The target can be an arbitrary C++ object. Not every |
| * proxy has the notion of a target, however. |
| * |
| * Proxy traps are grouped into fundamental and derived traps. Every proxy has |
| * to at least provide implementations for the fundamental traps, but the |
| * derived traps can be implemented in terms of the fundamental ones |
| * BaseProxyHandler provides implementations of the derived traps in terms of |
| * the (pure virtual) fundamental traps. |
| * |
| * To minimize code duplication, a set of abstract proxy handler classes is |
| * provided, from which other handlers may inherit. These abstract classes |
| * are organized in the following hierarchy: |
| * |
| * BaseProxyHandler |
| * | |
| * DirectProxyHandler |
| * | |
| * Wrapper |
| */ |
| |
| /* |
| * BaseProxyHandler is the most generic kind of proxy handler. It does not make |
| * any assumptions about the target. Consequently, it does not provide any |
| * default implementation for the fundamental traps. It does, however, implement |
| * the derived traps in terms of the fundamental ones. This allows consumers of |
| * this class to define any custom behavior they want. |
| */ |
| class JS_FRIEND_API(BaseProxyHandler) |
| { |
| void *mFamily; |
| bool mHasPrototype; |
| bool mHasPolicy; |
| protected: |
| // Subclasses may set this in their constructor. |
| void setHasPrototype(bool aHasPrototype) { mHasPrototype = aHasPrototype; } |
| void setHasPolicy(bool aHasPolicy) { mHasPolicy = aHasPolicy; } |
| |
| public: |
| explicit BaseProxyHandler(void *family); |
| virtual ~BaseProxyHandler(); |
| |
| bool hasPrototype() { |
| return mHasPrototype; |
| } |
| |
| bool hasPolicy() { |
| return mHasPolicy; |
| } |
| |
| inline void *family() { |
| return mFamily; |
| } |
| |
| virtual bool isOuterWindow() { |
| return false; |
| } |
| |
| virtual bool finalizeInBackground(Value priv) { |
| /* |
| * Called on creation of a proxy to determine whether its finalize |
| * method can be finalized on the background thread. |
| */ |
| return true; |
| } |
| |
| /* Policy enforcement traps. |
| * |
| * enter() allows the policy to specify whether the caller may perform |act| |
| * on the proxy's |id| property. In the case when |act| is CALL, |id| is |
| * generally JSID_VOID. |
| * |
| * The |act| parameter to enter() specifies the action being performed. |
| * If |bp| is false, the trap suggests that the caller throw (though it |
| * may still decide to squelch the error). |
| */ |
| enum Action { |
| GET, |
| SET, |
| CALL |
| }; |
| virtual bool enter(JSContext *cx, HandleObject wrapper, HandleId id, Action act, |
| bool *bp); |
| |
| /* ES5 Harmony fundamental proxy traps. */ |
| virtual bool preventExtensions(JSContext *cx, HandleObject proxy) = 0; |
| virtual bool getPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id, |
| PropertyDescriptor *desc, unsigned flags) = 0; |
| virtual bool getOwnPropertyDescriptor(JSContext *cx, HandleObject proxy, |
| HandleId id, PropertyDescriptor *desc, |
| unsigned flags) = 0; |
| virtual bool defineProperty(JSContext *cx, HandleObject proxy, HandleId id, |
| PropertyDescriptor *desc) = 0; |
| virtual bool getOwnPropertyNames(JSContext *cx, HandleObject proxy, |
| AutoIdVector &props) = 0; |
| virtual bool delete_(JSContext *cx, HandleObject proxy, HandleId id, bool *bp) = 0; |
| virtual bool enumerate(JSContext *cx, HandleObject proxy, AutoIdVector &props) = 0; |
| |
| /* ES5 Harmony derived proxy traps. */ |
| virtual bool has(JSContext *cx, HandleObject proxy, HandleId id, bool *bp); |
| virtual bool hasOwn(JSContext *cx, HandleObject proxy, HandleId id, bool *bp); |
| virtual bool get(JSContext *cx, HandleObject proxy, HandleObject receiver, |
| HandleId id, MutableHandleValue vp); |
| virtual bool set(JSContext *cx, HandleObject proxy, HandleObject receiver, |
| HandleId id, bool strict, MutableHandleValue vp); |
| virtual bool keys(JSContext *cx, HandleObject proxy, AutoIdVector &props); |
| virtual bool iterate(JSContext *cx, HandleObject proxy, unsigned flags, |
| MutableHandleValue vp); |
| |
| /* Spidermonkey extensions. */ |
| virtual bool isExtensible(JSObject *proxy) = 0; |
| virtual bool call(JSContext *cx, HandleObject proxy, const CallArgs &args); |
| virtual bool construct(JSContext *cx, HandleObject proxy, const CallArgs &args); |
| virtual bool nativeCall(JSContext *cx, IsAcceptableThis test, NativeImpl impl, CallArgs args); |
| virtual bool hasInstance(JSContext *cx, HandleObject proxy, MutableHandleValue v, bool *bp); |
| virtual bool objectClassIs(HandleObject obj, ESClassValue classValue, JSContext *cx); |
| virtual const char *className(JSContext *cx, HandleObject proxy); |
| virtual JSString *fun_toString(JSContext *cx, HandleObject proxy, unsigned indent); |
| virtual bool regexp_toShared(JSContext *cx, HandleObject proxy, RegExpGuard *g); |
| virtual bool defaultValue(JSContext *cx, HandleObject obj, JSType hint, MutableHandleValue vp); |
| virtual void finalize(JSFreeOp *fop, JSObject *proxy); |
| virtual bool getElementIfPresent(JSContext *cx, HandleObject obj, HandleObject receiver, |
| uint32_t index, MutableHandleValue vp, bool *present); |
| virtual bool getPrototypeOf(JSContext *cx, HandleObject proxy, MutableHandleObject protop); |
| |
| /* See comment for weakmapKeyDelegateOp in jsclass.h. */ |
| virtual JSObject *weakmapKeyDelegate(JSObject *proxy); |
| }; |
| |
| /* |
| * DirectProxyHandler includes a notion of a target object. All traps are |
| * reimplemented such that they forward their behavior to the target. This |
| * allows consumers of this class to forward to another object as transparently |
| * and efficiently as possible. |
| */ |
| class JS_PUBLIC_API(DirectProxyHandler) : public BaseProxyHandler |
| { |
| public: |
| explicit DirectProxyHandler(void *family); |
| |
| /* ES5 Harmony fundamental proxy traps. */ |
| virtual bool preventExtensions(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE; |
| virtual bool getPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id, |
| PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE; |
| virtual bool getOwnPropertyDescriptor(JSContext *cx, HandleObject proxy, |
| HandleId id, PropertyDescriptor *desc, |
| unsigned flags) MOZ_OVERRIDE; |
| virtual bool defineProperty(JSContext *cx, HandleObject proxy, HandleId id, |
| PropertyDescriptor *desc) MOZ_OVERRIDE; |
| virtual bool getOwnPropertyNames(JSContext *cx, HandleObject proxy, |
| AutoIdVector &props) MOZ_OVERRIDE; |
| virtual bool delete_(JSContext *cx, HandleObject proxy, HandleId id, |
| bool *bp) MOZ_OVERRIDE; |
| virtual bool enumerate(JSContext *cx, HandleObject proxy, |
| AutoIdVector &props) MOZ_OVERRIDE; |
| |
| /* ES5 Harmony derived proxy traps. */ |
| virtual bool has(JSContext *cx, HandleObject proxy, HandleId id, |
| bool *bp) MOZ_OVERRIDE; |
| virtual bool hasOwn(JSContext *cx, HandleObject proxy, HandleId id, |
| bool *bp) MOZ_OVERRIDE; |
| virtual bool get(JSContext *cx, HandleObject proxy, HandleObject receiver, |
| HandleId id, MutableHandleValue vp) MOZ_OVERRIDE; |
| virtual bool set(JSContext *cx, HandleObject proxy, HandleObject receiver, |
| HandleId id, bool strict, MutableHandleValue vp) MOZ_OVERRIDE; |
| virtual bool keys(JSContext *cx, HandleObject proxy, |
| AutoIdVector &props) MOZ_OVERRIDE; |
| virtual bool iterate(JSContext *cx, HandleObject proxy, unsigned flags, |
| MutableHandleValue vp) MOZ_OVERRIDE; |
| |
| /* Spidermonkey extensions. */ |
| virtual bool isExtensible(JSObject *proxy) MOZ_OVERRIDE; |
| virtual bool call(JSContext *cx, HandleObject proxy, const CallArgs &args) MOZ_OVERRIDE; |
| virtual bool construct(JSContext *cx, HandleObject proxy, const CallArgs &args) MOZ_OVERRIDE; |
| virtual bool nativeCall(JSContext *cx, IsAcceptableThis test, NativeImpl impl, |
| CallArgs args) MOZ_OVERRIDE; |
| virtual bool hasInstance(JSContext *cx, HandleObject proxy, MutableHandleValue v, |
| bool *bp) MOZ_OVERRIDE; |
| virtual bool objectClassIs(HandleObject obj, ESClassValue classValue, |
| JSContext *cx) MOZ_OVERRIDE; |
| virtual const char *className(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE; |
| virtual JSString *fun_toString(JSContext *cx, HandleObject proxy, |
| unsigned indent) MOZ_OVERRIDE; |
| virtual bool regexp_toShared(JSContext *cx, HandleObject proxy, |
| RegExpGuard *g) MOZ_OVERRIDE; |
| virtual bool defaultValue(JSContext *cx, HandleObject obj, JSType hint, |
| MutableHandleValue vp) MOZ_OVERRIDE; |
| virtual JSObject *weakmapKeyDelegate(JSObject *proxy); |
| }; |
| |
| /* Dispatch point for handlers that executes the appropriate C++ or scripted traps. */ |
| class Proxy |
| { |
| public: |
| /* ES5 Harmony fundamental proxy traps. */ |
| static bool preventExtensions(JSContext *cx, HandleObject proxy); |
| static bool getPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id, |
| PropertyDescriptor *desc, unsigned flags); |
| static bool getPropertyDescriptor(JSContext *cx, HandleObject proxy, unsigned flags, HandleId id, |
| MutableHandleValue vp); |
| static bool getOwnPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id, |
| PropertyDescriptor *desc, unsigned flags); |
| static bool getOwnPropertyDescriptor(JSContext *cx, HandleObject proxy, unsigned flags, HandleId id, |
| MutableHandleValue vp); |
| static bool defineProperty(JSContext *cx, HandleObject proxy, HandleId id, PropertyDescriptor *desc); |
| static bool defineProperty(JSContext *cx, HandleObject proxy, HandleId id, HandleValue v); |
| static bool getOwnPropertyNames(JSContext *cx, HandleObject proxy, AutoIdVector &props); |
| static bool delete_(JSContext *cx, HandleObject proxy, HandleId id, bool *bp); |
| static bool enumerate(JSContext *cx, HandleObject proxy, AutoIdVector &props); |
| |
| /* ES5 Harmony derived proxy traps. */ |
| static bool has(JSContext *cx, HandleObject proxy, HandleId id, bool *bp); |
| static bool hasOwn(JSContext *cx, HandleObject proxy, HandleId id, bool *bp); |
| static bool get(JSContext *cx, HandleObject proxy, HandleObject receiver, HandleId id, |
| MutableHandleValue vp); |
| static bool getElementIfPresent(JSContext *cx, HandleObject proxy, HandleObject receiver, |
| uint32_t index, MutableHandleValue vp, bool *present); |
| static bool set(JSContext *cx, HandleObject proxy, HandleObject receiver, HandleId id, |
| bool strict, MutableHandleValue vp); |
| static bool keys(JSContext *cx, HandleObject proxy, AutoIdVector &props); |
| static bool iterate(JSContext *cx, HandleObject proxy, unsigned flags, MutableHandleValue vp); |
| |
| /* Spidermonkey extensions. */ |
| static bool isExtensible(JSObject *proxy); |
| static bool call(JSContext *cx, HandleObject proxy, const CallArgs &args); |
| static bool construct(JSContext *cx, HandleObject proxy, const CallArgs &args); |
| static bool nativeCall(JSContext *cx, IsAcceptableThis test, NativeImpl impl, CallArgs args); |
| static bool hasInstance(JSContext *cx, HandleObject proxy, MutableHandleValue v, bool *bp); |
| static bool objectClassIs(HandleObject obj, ESClassValue classValue, JSContext *cx); |
| static const char *className(JSContext *cx, HandleObject proxy); |
| static JSString *fun_toString(JSContext *cx, HandleObject proxy, unsigned indent); |
| static bool regexp_toShared(JSContext *cx, HandleObject proxy, RegExpGuard *g); |
| static bool defaultValue(JSContext *cx, HandleObject obj, JSType hint, MutableHandleValue vp); |
| static bool getPrototypeOf(JSContext *cx, HandleObject proxy, MutableHandleObject protop); |
| |
| static JSObject * const LazyProto; |
| }; |
| |
| inline bool IsObjectProxyClass(const Class *clasp) |
| { |
| return clasp == &js::ObjectProxyClass || clasp == &js::OuterWindowProxyClass; |
| } |
| |
| inline bool IsFunctionProxyClass(const Class *clasp) |
| { |
| return clasp == &js::FunctionProxyClass; |
| } |
| |
| inline bool IsObjectProxy(JSObject *obj) |
| { |
| return IsObjectProxyClass(GetObjectClass(obj)); |
| } |
| |
| inline bool IsFunctionProxy(JSObject *obj) |
| { |
| return IsFunctionProxyClass(GetObjectClass(obj)); |
| } |
| |
| inline bool IsProxy(JSObject *obj) |
| { |
| Class *clasp = GetObjectClass(obj); |
| return IsObjectProxyClass(clasp) || IsFunctionProxyClass(clasp); |
| } |
| |
| /* Shared between object and function proxies. */ |
| /* |
| * NOTE: JSSLOT_PROXY_PRIVATE is 0, because that way slot 0 is usable by API |
| * clients for both proxy and non-proxy objects. So an API client that only |
| * needs to store one slot's worth of data doesn't need to branch on what sort |
| * of object it has. |
| */ |
| const uint32_t JSSLOT_PROXY_PRIVATE = 0; |
| const uint32_t JSSLOT_PROXY_HANDLER = 1; |
| const uint32_t JSSLOT_PROXY_EXTRA = 2; |
| /* Function proxies only. */ |
| const uint32_t JSSLOT_PROXY_CALL = 4; |
| const uint32_t JSSLOT_PROXY_CONSTRUCT = 5; |
| |
| inline BaseProxyHandler * |
| GetProxyHandler(JSObject *obj) |
| { |
| JS_ASSERT(IsProxy(obj)); |
| return (BaseProxyHandler *) GetReservedSlot(obj, JSSLOT_PROXY_HANDLER).toPrivate(); |
| } |
| |
| inline const Value & |
| GetProxyPrivate(JSObject *obj) |
| { |
| JS_ASSERT(IsProxy(obj)); |
| return GetReservedSlot(obj, JSSLOT_PROXY_PRIVATE); |
| } |
| |
| inline JSObject * |
| GetProxyTargetObject(JSObject *obj) |
| { |
| JS_ASSERT(IsProxy(obj)); |
| return GetProxyPrivate(obj).toObjectOrNull(); |
| } |
| |
| inline const Value & |
| GetProxyExtra(JSObject *obj, size_t n) |
| { |
| JS_ASSERT(IsProxy(obj)); |
| return GetReservedSlot(obj, JSSLOT_PROXY_EXTRA + n); |
| } |
| |
| inline void |
| SetProxyHandler(JSObject *obj, BaseProxyHandler *handler) |
| { |
| JS_ASSERT(IsProxy(obj)); |
| SetReservedSlot(obj, JSSLOT_PROXY_HANDLER, PrivateValue(handler)); |
| } |
| |
| inline void |
| SetProxyExtra(JSObject *obj, size_t n, const Value &extra) |
| { |
| JS_ASSERT(IsProxy(obj)); |
| JS_ASSERT(n <= 1); |
| SetReservedSlot(obj, JSSLOT_PROXY_EXTRA + n, extra); |
| } |
| |
| enum ProxyCallable { |
| ProxyNotCallable = false, |
| ProxyIsCallable = true |
| }; |
| |
| JS_FRIEND_API(JSObject *) |
| NewProxyObject(JSContext *cx, BaseProxyHandler *handler, HandleValue priv, |
| JSObject *proto, JSObject *parent, ProxyCallable callable = ProxyNotCallable); |
| |
| JSObject * |
| RenewProxyObject(JSContext *cx, JSObject *obj, BaseProxyHandler *handler, Value priv); |
| |
| class JS_FRIEND_API(AutoEnterPolicy) |
| { |
| public: |
| typedef BaseProxyHandler::Action Action; |
| AutoEnterPolicy(JSContext *cx, BaseProxyHandler *handler, |
| HandleObject wrapper, HandleId id, Action act, bool mayThrow) |
| #ifdef JS_DEBUG |
| : context(NULL) |
| #endif |
| { |
| allow = handler->hasPolicy() ? handler->enter(cx, wrapper, id, act, &rv) |
| : true; |
| recordEnter(cx, wrapper, id); |
| // 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 && !JS_IsExceptionPending(cx)) |
| reportError(cx, id); |
| } |
| |
| virtual ~AutoEnterPolicy() { recordLeave(); } |
| inline bool allowed() { return allow; } |
| inline bool returnValue() { JS_ASSERT(!allowed()); return rv; } |
| |
| protected: |
| // no-op constructor for subclass |
| AutoEnterPolicy() |
| #ifdef JS_DEBUG |
| : context(NULL) |
| #endif |
| {}; |
| void reportError(JSContext *cx, jsid id); |
| bool allow; |
| bool rv; |
| |
| #ifdef JS_DEBUG |
| JSContext *context; |
| mozilla::Maybe<HandleObject> enteredProxy; |
| mozilla::Maybe<HandleId> enteredId; |
| // NB: We explicitly don't track the entered action here, because sometimes |
| // SET traps do an implicit GET during their implementation, leading to |
| // spurious assertions. |
| AutoEnterPolicy *prev; |
| void recordEnter(JSContext *cx, HandleObject proxy, HandleId id); |
| void recordLeave(); |
| |
| friend JS_FRIEND_API(void) assertEnteredPolicy(JSContext *cx, JSObject *proxy, jsid id); |
| #else |
| inline void recordEnter(JSContext *cx, JSObject *proxy, jsid id) {} |
| inline void recordLeave() {} |
| #endif |
| |
| }; |
| |
| #ifdef JS_DEBUG |
| class JS_FRIEND_API(AutoWaivePolicy) : public AutoEnterPolicy { |
| public: |
| AutoWaivePolicy(JSContext *cx, HandleObject proxy, HandleId id) |
| { |
| allow = true; |
| recordEnter(cx, proxy, id); |
| } |
| }; |
| #else |
| class JS_FRIEND_API(AutoWaivePolicy) { |
| public: AutoWaivePolicy(JSContext *cx, HandleObject proxy, HandleId id) {}; |
| }; |
| #endif |
| |
| } /* namespace js */ |
| |
| extern JS_FRIEND_API(JSObject *) |
| js_InitProxyClass(JSContext *cx, JS::HandleObject obj); |
| |
| #endif /* jsproxy_h */ |
