gecko-dev/dom/bindings/DOMJSProxyHandler.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 mozilla_dom_DOMJSProxyHandler_h
#define mozilla_dom_DOMJSProxyHandler_h
#include "mozilla/Attributes.h"
#include "mozilla/Likely.h"
#include "jsapi.h"
#include "js/Proxy.h"
#include "nsString.h"
#define DOM_PROXY_OBJECT_SLOT js::PROXY_PRIVATE_SLOT
namespace mozilla {
namespace dom {
enum {
/**
* DOM proxies have an extra slot for the expando object at index
* JSPROXYSLOT_EXPANDO.
*
* The expando object is a plain JSObject whose properties correspond to
* "expandos" (custom properties set by the script author).
*
* The exact value stored in the JSPROXYSLOT_EXPANDO slot depends on whether
* the interface is annotated with the [OverrideBuiltins] extended attribute.
*
* If it is, the proxy is initialized with a PrivateValue, which contains a
* pointer to a js::ExpandoAndGeneration object; this contains a pointer to
* the actual expando object as well as the "generation" of the object.
*
* If it is not, the proxy is initialized with an UndefinedValue. In
* EnsureExpandoObject, it is set to an ObjectValue that points to the
* expando object directly. (It is set back to an UndefinedValue only when
* the object is about to die.)
*/
JSPROXYSLOT_EXPANDO = 0
};
template<typename T> struct Prefable;
class BaseDOMProxyHandler : public js::BaseProxyHandler
{
public:
explicit MOZ_CONSTEXPR BaseDOMProxyHandler(const void* aProxyFamily, bool aHasPrototype = false)
: js::BaseProxyHandler(aProxyFamily, aHasPrototype)
{}
// Implementations of methods that can be implemented in terms of
// other lower-level methods.
bool getOwnPropertyDescriptor(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id,
JS::MutableHandle<JSPropertyDescriptor> desc) const override;
virtual bool ownPropertyKeys(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::AutoIdVector &props) const override;
virtual bool enumerate(JSContext *cx, JS::Handle<JSObject*> proxy,
JS::MutableHandle<JSObject*> objp) const override;
// We override getOwnEnumerablePropertyKeys() and implement it directly
// instead of using the default implementation, which would call
// ownPropertyKeys and then filter out the non-enumerable ones. This avoids
// unnecessary work during enumeration.
virtual bool getOwnEnumerablePropertyKeys(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::AutoIdVector &props) const override;
bool watch(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::Handle<JSObject*> callable) const override;
bool unwatch(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id) const override;
protected:
// Hook for subclasses to implement shared ownPropertyKeys()/keys()
// functionality. The "flags" argument is either JSITER_OWNONLY (for keys())
// or JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS (for
// ownPropertyKeys()).
virtual bool ownPropNames(JSContext* cx, JS::Handle<JSObject*> proxy,
unsigned flags,
JS::AutoIdVector& props) const = 0;
// Hook for subclasses to allow set() to ignore named props while other things
// that look at property descriptors see them. This is intentionally not
// named getOwnPropertyDescriptor to avoid subclasses that override it hiding
// our public getOwnPropertyDescriptor.
virtual bool getOwnPropDescriptor(JSContext* cx,
JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id,
bool ignoreNamedProps,
JS::MutableHandle<JSPropertyDescriptor> desc) const = 0;
};
class DOMProxyHandler : public BaseDOMProxyHandler
{
public:
MOZ_CONSTEXPR DOMProxyHandler()
: BaseDOMProxyHandler(&family)
{}
bool defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::Handle<JSPropertyDescriptor> desc,
JS::ObjectOpResult &result) const override
{
bool unused;
return defineProperty(cx, proxy, id, desc, result, &unused);
}
virtual bool defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::Handle<JSPropertyDescriptor> desc,
JS::ObjectOpResult &result, bool *defined) const;
bool delete_(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::ObjectOpResult &result) const override;
bool preventExtensions(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::ObjectOpResult& result) const override;
bool isExtensible(JSContext *cx, JS::Handle<JSObject*> proxy, bool *extensible)
const override;
bool has(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
bool* bp) const override;
Bug 1142794 - Change 'receiver' argument to SetProperty functions and ProxyHandler::set methods to be a HandleValue. r=Waldo. Also: Change signature of these functions and methods to all have the same arguments in the same order: (cx, obj, id, v, receiver). Also change v from MutableHandleValue to HandleValue. There is no change in behavior. In fact the new error message `JSMSG_SET_NON_OBJECT_RECEIVER` is impossible to trigger from scripts for now, I think (after re-reading the whole patch with this in mind). JS_ForwardSetPropertyTo is the only way to get a non-object receiver into the engine, but no caller currently does so. We're installing new pipes here, and they should work, but for now it's the same cold water flowing through as before. Actually hooking up the hot water is left for another bug (one with tests, not to put too fine a point on it). Notes: * InvokeGetterOrSetter had to be split into two functions: InvokeGetter takes a MutableHandleValue out-param, InvokeSetter a HandleValue in-param. * Watchpoints can still tamper with values being assigned. So can JSSetterOps. I'm pleased we can support this craziness in a way that doesn't have to spread via the type system to encompass the entire codebase. * Change in GlobalObject::setIntrinsicValue is not really a change. Yes, it asserted before, but an exception thrown during self-hosting initialization is not going to go unnoticed either. * Since the receiver argument to js::SetProperty() is at the end now, it makes sense for it to be optional. Some callers look nicer. --HG-- extra : rebase_source : e89f916fe267800bc73890e11aceef5c4855b272
2015-03-01 19:16:19 +00:00
bool set(JSContext *cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
JS::Handle<JS::Value> v, JS::Handle<JS::Value> receiver, JS::ObjectOpResult &result)
const override;
/*
* If assigning to proxy[id] hits a named setter with OverrideBuiltins or
* an indexed setter, call it and set *done to true on success. Otherwise, set
* *done to false.
*/
virtual bool setCustom(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
Bug 1142794 - Change 'receiver' argument to SetProperty functions and ProxyHandler::set methods to be a HandleValue. r=Waldo. Also: Change signature of these functions and methods to all have the same arguments in the same order: (cx, obj, id, v, receiver). Also change v from MutableHandleValue to HandleValue. There is no change in behavior. In fact the new error message `JSMSG_SET_NON_OBJECT_RECEIVER` is impossible to trigger from scripts for now, I think (after re-reading the whole patch with this in mind). JS_ForwardSetPropertyTo is the only way to get a non-object receiver into the engine, but no caller currently does so. We're installing new pipes here, and they should work, but for now it's the same cold water flowing through as before. Actually hooking up the hot water is left for another bug (one with tests, not to put too fine a point on it). Notes: * InvokeGetterOrSetter had to be split into two functions: InvokeGetter takes a MutableHandleValue out-param, InvokeSetter a HandleValue in-param. * Watchpoints can still tamper with values being assigned. So can JSSetterOps. I'm pleased we can support this craziness in a way that doesn't have to spread via the type system to encompass the entire codebase. * Change in GlobalObject::setIntrinsicValue is not really a change. Yes, it asserted before, but an exception thrown during self-hosting initialization is not going to go unnoticed either. * Since the receiver argument to js::SetProperty() is at the end now, it makes sense for it to be optional. Some callers look nicer. --HG-- extra : rebase_source : e89f916fe267800bc73890e11aceef5c4855b272
2015-03-01 19:16:19 +00:00
JS::Handle<JS::Value> v, bool *done) const;
static JSObject* GetExpandoObject(JSObject* obj);
/* GetAndClearExpandoObject does not DROP or clear the preserving wrapper flag. */
static JSObject* GetAndClearExpandoObject(JSObject* obj);
static JSObject* EnsureExpandoObject(JSContext* cx,
JS::Handle<JSObject*> obj);
static const char family;
};
inline bool IsDOMProxy(JSObject *obj)
{
const js::Class* clasp = js::GetObjectClass(obj);
return clasp->isProxy() &&
js::GetProxyHandler(obj)->family() == &DOMProxyHandler::family;
}
inline const DOMProxyHandler*
GetDOMProxyHandler(JSObject* obj)
{
MOZ_ASSERT(IsDOMProxy(obj));
return static_cast<const DOMProxyHandler*>(js::GetProxyHandler(obj));
}
extern jsid s_length_id;
int32_t IdToInt32(JSContext* cx, JS::Handle<jsid> id);
// XXXbz this should really return uint32_t, with the maximum value
// meaning "not an index"...
inline int32_t
GetArrayIndexFromId(JSContext* cx, JS::Handle<jsid> id)
{
if (MOZ_LIKELY(JSID_IS_INT(id))) {
return JSID_TO_INT(id);
}
if (MOZ_LIKELY(id == s_length_id)) {
return -1;
}
if (MOZ_LIKELY(JSID_IS_ATOM(id))) {
JSAtom* atom = JSID_TO_ATOM(id);
char16_t s;
{
JS::AutoCheckCannotGC nogc;
if (js::AtomHasLatin1Chars(atom)) {
s = *js::GetLatin1AtomChars(nogc, atom);
} else {
s = *js::GetTwoByteAtomChars(nogc, atom);
}
}
if (MOZ_LIKELY((unsigned)s >= 'a' && (unsigned)s <= 'z'))
return -1;
uint32_t i;
JSLinearString* str = js::AtomToLinearString(JSID_TO_ATOM(id));
return js::StringIsArrayIndex(str, &i) ? i : -1;
}
return IdToInt32(cx, id);
}
inline bool
IsArrayIndex(int32_t index)
{
return index >= 0;
}
inline void
FillPropertyDescriptor(JS::MutableHandle<JSPropertyDescriptor> desc,
JSObject* obj, bool readonly, bool enumerable = true)
{
desc.object().set(obj);
desc.setAttributes((readonly ? JSPROP_READONLY : 0) |
(enumerable ? JSPROP_ENUMERATE : 0));
desc.setGetter(nullptr);
desc.setSetter(nullptr);
}
inline void
FillPropertyDescriptor(JS::MutableHandle<JSPropertyDescriptor> desc,
JSObject* obj, JS::Value v,
bool readonly, bool enumerable = true)
{
desc.value().set(v);
FillPropertyDescriptor(desc, obj, readonly, enumerable);
}
inline void
FillPropertyDescriptor(JS::MutableHandle<JSPropertyDescriptor> desc,
JSObject* obj, unsigned attributes, JS::Value v)
{
desc.object().set(obj);
desc.value().set(v);
desc.setAttributes(attributes);
desc.setGetter(nullptr);
desc.setSetter(nullptr);
}
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_DOMProxyHandler_h */