Source code

Revision control

Other Tools

/* -*- 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/. */
/*
* Specify information about DOMProxy proxies in the DOM, for use by ICs.
*
* Embedders who don't need to define particularly high-performance proxies that
* can have random properties added to them can ignore this header.
*/
#ifndef js_friend_DOMProxy_h
#define js_friend_DOMProxy_h
#include <stddef.h> // size_t
#include <stdint.h> // uint64_t
#include "jstypes.h" // JS_PUBLIC_API
#include "js/Id.h" // JS::PropertyKey
#include "js/RootingAPI.h" // JS::Handle, JS::Heap
#include "js/Value.h" // JS::UndefinedValue, JS::Value
struct JS_PUBLIC_API JSContext;
class JS_PUBLIC_API JSObject;
namespace JS {
/*
* The DOMProxyShadowsCheck function will be called to check if the property for
* id should be gotten from the prototype, or if there is an own property that
* shadows it.
* * If ShadowsViaDirectExpando is returned, then the slot at
* listBaseExpandoSlot contains an expando object which has the property in
* question.
* * If ShadowsViaIndirectExpando is returned, then the slot at
* listBaseExpandoSlot contains a private pointer to an ExpandoAndGeneration
* and the expando object in the ExpandoAndGeneration has the property in
* question.
* * If DoesntShadow is returned then the slot at listBaseExpandoSlot should
* either be undefined or point to an expando object that would contain the
* own property.
* * If DoesntShadowUnique is returned then the slot at listBaseExpandoSlot
* should contain a private pointer to a ExpandoAndGeneration, which contains
* a JS::Value that should either be undefined or point to an expando object,
* and a uint64 value. If that value changes then the IC for getting a
* property will be invalidated.
* * If Shadows is returned, that means the property is an own property of the
* proxy but doesn't live on the expando object.
*/
struct ExpandoAndGeneration {
ExpandoAndGeneration() : expando(JS::UndefinedValue()), generation(0) {}
void OwnerUnlinked() { ++generation; }
static constexpr size_t offsetOfExpando() {
return offsetof(ExpandoAndGeneration, expando);
}
static constexpr size_t offsetOfGeneration() {
return offsetof(ExpandoAndGeneration, generation);
}
Heap<Value> expando;
uint64_t generation;
};
enum class DOMProxyShadowsResult {
ShadowCheckFailed,
Shadows,
DoesntShadow,
DoesntShadowUnique,
ShadowsViaDirectExpando,
ShadowsViaIndirectExpando
};
using DOMProxyShadowsCheck = DOMProxyShadowsResult (*)(JSContext*,
Handle<JSObject*>,
Handle<JS::PropertyKey>);
extern JS_PUBLIC_API void SetDOMProxyInformation(
const void* domProxyHandlerFamily,
DOMProxyShadowsCheck domProxyShadowsCheck,
const void* domRemoteProxyHandlerFamily);
} // namespace JS
#endif // js_friend_DOMProxy_h