gecko/dom/bindings/DOMJSClass.h

115 lines
3.5 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* 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_DOMJSClass_h
#define mozilla_dom_DOMJSClass_h
#include "jsapi.h"
#include "jsfriendapi.h"
#include "mozilla/dom/PrototypeList.h" // auto-generated
// We use slot 0 for holding the raw object. This is safe for both
// globals and non-globals.
#define DOM_OBJECT_SLOT 0
// All DOM globals must have a slot at DOM_PROTOTYPE_SLOT. We have to
// start at 1 past JSCLASS_GLOBAL_SLOT_COUNT because XPConnect uses
// that one.
#define DOM_PROTOTYPE_SLOT (JSCLASS_GLOBAL_SLOT_COUNT + 1)
// We use these flag bits for the new bindings.
#define JSCLASS_DOM_GLOBAL JSCLASS_USERBIT1
// NOTE: This is baked into the Ion JIT as 0 in codegen for LGetDOMProperty and
// LSetDOMProperty. Those constants need to be changed accordingly if this value
// changes.
#define DOM_PROTO_INSTANCE_CLASS_SLOT 0
namespace mozilla {
namespace dom {
typedef bool
(* ResolveProperty)(JSContext* cx, JSObject* wrapper, jsid id, bool set,
JSPropertyDescriptor* desc);
typedef bool
(* EnumerateProperties)(JSContext* cx, JSObject* wrapper,
JS::AutoIdVector& props);
struct NativePropertyHooks
{
ResolveProperty mResolveOwnProperty;
ResolveProperty mResolveProperty;
EnumerateProperties mEnumerateOwnProperties;
EnumerateProperties mEnumerateProperties;
const NativePropertyHooks *mProtoHooks;
};
struct DOMClass
{
// A list of interfaces that this object implements, in order of decreasing
// derivedness.
const prototypes::ID mInterfaceChain[prototypes::id::_ID_Count];
// We store the DOM object in reserved slot with index DOM_OBJECT_SLOT or in
// the proxy private if we use a proxy object.
// Sometimes it's an nsISupports and sometimes it's not; this class tells
// us which it is.
const bool mDOMObjectIsISupports;
const NativePropertyHooks* mNativeHooks;
};
// Special JSClass for reflected DOM objects.
struct DOMJSClass
{
// It would be nice to just inherit from JSClass, but that precludes pure
// compile-time initialization of the form |DOMJSClass = {...};|, since C++
// only allows brace initialization for aggregate/POD types.
JSClass mBase;
DOMClass mClass;
static DOMJSClass* FromJSClass(JSClass* base) {
MOZ_ASSERT(base->flags & JSCLASS_IS_DOMJSCLASS);
return reinterpret_cast<DOMJSClass*>(base);
}
static const DOMJSClass* FromJSClass(const JSClass* base) {
MOZ_ASSERT(base->flags & JSCLASS_IS_DOMJSCLASS);
return reinterpret_cast<const DOMJSClass*>(base);
}
static DOMJSClass* FromJSClass(js::Class* base) {
return FromJSClass(Jsvalify(base));
}
static const DOMJSClass* FromJSClass(const js::Class* base) {
return FromJSClass(Jsvalify(base));
}
JSClass* ToJSClass() { return &mBase; }
};
inline bool
HasProtoOrIfaceArray(JSObject* global)
{
MOZ_ASSERT(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL);
// This can be undefined if we GC while creating the global
return !js::GetReservedSlot(global, DOM_PROTOTYPE_SLOT).isUndefined();
}
inline JSObject**
GetProtoOrIfaceArray(JSObject* global)
{
MOZ_ASSERT(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL);
return static_cast<JSObject**>(
js::GetReservedSlot(global, DOM_PROTOTYPE_SLOT).toPrivate());
}
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_DOMJSClass_h */