gecko/dom/bindings/DOMJSClass.h

275 lines
9.2 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/Assertions.h"
#include "mozilla/dom/PrototypeList.h" // auto-generated
class nsCycleCollectionParticipant;
// We use slot 0 for holding the raw object. This is safe for both
// globals and non-globals.
#define DOM_OBJECT_SLOT 0
// We use slot 1 for holding the expando object. This is not safe for globals
// until bug 760095 is fixed, so that bug blocks converting Window to new
// bindings.
#define DOM_XRAY_EXPANDO_SLOT 1
// We use slot 2 for holding either a JS::ObjectValue which points to the cached
// SOW or JS::UndefinedValue if this class doesn't need SOWs. This is not safe
// for globals until bug 760095 is fixed, so that bug blocks converting Window
// to new bindings.
#define DOM_OBJECT_SLOT_SOW 2
// All DOM globals must have a slot at DOM_PROTOTYPE_SLOT.
#define DOM_PROTOTYPE_SLOT JSCLASS_GLOBAL_SLOT_COUNT
// We use these flag bits for the new bindings.
#define JSCLASS_DOM_GLOBAL JSCLASS_USERBIT1
#define JSCLASS_IS_DOMIFACEANDPROTOJSCLASS JSCLASS_USERBIT2
// 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
// Interface objects store a number of reserved slots equal to
// DOM_INTERFACE_SLOTS_BASE + number of named constructors.
#define DOM_INTERFACE_SLOTS_BASE (DOM_XRAY_EXPANDO_SLOT + 1)
// Interface prototype objects store a number of reserved slots equal to
// DOM_INTERFACE_PROTO_SLOTS_BASE or DOM_INTERFACE_PROTO_SLOTS_BASE + 1 if a
// slot for the unforgeable holder is needed.
#define DOM_INTERFACE_PROTO_SLOTS_BASE (DOM_XRAY_EXPANDO_SLOT + 1)
static_assert(DOM_PROTO_INSTANCE_CLASS_SLOT != DOM_XRAY_EXPANDO_SLOT,
"Interface prototype object use both of these, so they must "
"not be the same slot.");
namespace mozilla {
namespace dom {
typedef bool
(* ResolveOwnProperty)(JSContext* cx, JS::Handle<JSObject*> wrapper,
JS::Handle<JSObject*> obj, JS::Handle<jsid> id,
JSPropertyDescriptor* desc, unsigned flags);
typedef bool
(* EnumerateOwnProperties)(JSContext* cx, JS::Handle<JSObject*> wrapper,
JS::Handle<JSObject*> obj,
JS::AutoIdVector& props);
struct ConstantSpec
{
const char* name;
JS::Value value;
};
typedef bool (*PropertyEnabled)(JSContext* cx, JSObject* global);
template<typename T>
struct Prefable {
inline bool isEnabled(JSContext* cx, JSObject* obj) const {
return enabled &&
(!enabledFunc ||
enabledFunc(cx, js::GetGlobalForObjectCrossCompartment(obj)));
}
// A boolean indicating whether this set of specs is enabled
bool enabled;
// A function pointer to a function that can say the property is disabled
// even if "enabled" is set to true. If the pointer is null the value of
// "enabled" is used as-is.
PropertyEnabled enabledFunc;
// Array of specs, terminated in whatever way is customary for T.
// Null to indicate a end-of-array for Prefable, when such an
// indicator is needed.
const T* specs;
};
struct NativeProperties
{
const Prefable<const JSFunctionSpec>* staticMethods;
jsid* staticMethodIds;
const JSFunctionSpec* staticMethodsSpecs;
const Prefable<const JSPropertySpec>* staticAttributes;
jsid* staticAttributeIds;
const JSPropertySpec* staticAttributeSpecs;
const Prefable<const JSFunctionSpec>* methods;
jsid* methodIds;
const JSFunctionSpec* methodsSpecs;
const Prefable<const JSPropertySpec>* attributes;
jsid* attributeIds;
const JSPropertySpec* attributeSpecs;
const Prefable<const JSPropertySpec>* unforgeableAttributes;
jsid* unforgeableAttributeIds;
const JSPropertySpec* unforgeableAttributeSpecs;
const Prefable<const ConstantSpec>* constants;
jsid* constantIds;
const ConstantSpec* constantSpecs;
};
struct NativePropertiesHolder
{
const NativeProperties* regular;
const NativeProperties* chromeOnly;
};
// Helper structure for Xrays for DOM binding objects. The same instance is used
// for instances, interface objects and interface prototype objects of a
// specific interface.
struct NativePropertyHooks
{
// The hook to call for resolving indexed or named properties. May be null if
// there can't be any.
ResolveOwnProperty mResolveOwnProperty;
// The hook to call for enumerating indexed or named properties. May be null
// if there can't be any.
EnumerateOwnProperties mEnumerateOwnProperties;
// The property arrays for this interface.
NativePropertiesHolder mNativeProperties;
// This will be set to the ID of the interface prototype object for the
// interface, if it has one. If it doesn't have one it will be set to
// prototypes::id::_ID_Count.
prototypes::ID mPrototypeID;
// This will be set to the ID of the interface object for the interface, if it
// has one. If it doesn't have one it will be set to
// constructors::id::_ID_Count.
constructors::ID mConstructorID;
// The NativePropertyHooks instance for the parent interface.
const NativePropertyHooks* mProtoHooks;
};
enum DOMObjectType {
eInstance,
eInterface,
eInterfacePrototype
};
typedef JSObject* (*ParentGetter)(JSContext* aCx, JS::Handle<JSObject*> aObj);
/**
* Returns a handle to the relevent WebIDL prototype object for the given global
* (which may be a handle to null on out of memory). Once allocated, the
* prototype object is guaranteed to exist as long as the global does, since the
* global traces its array of WebIDL prototypes and constructors.
*/
typedef JS::Handle<JSObject*> (*ProtoGetter)(JSContext* aCx,
JS::Handle<JSObject*> aGlobal);
struct DOMClass
{
// A list of interfaces that this object implements, in order of decreasing
// derivedness.
const prototypes::ID mInterfaceChain[MAX_PROTOTYPE_CHAIN_LENGTH];
// 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;
ParentGetter mGetParent;
ProtoGetter mGetProto;
// This stores the CC participant for the native, null if this class is for a
// worker or for a native inheriting from nsISupports (we can get the CC
// participant by QI'ing in that case).
nsCycleCollectionParticipant* mParticipant;
};
// 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; }
};
// Special JSClass for DOM interface and interface prototype objects.
struct DOMIfaceAndProtoJSClass
{
// It would be nice to just inherit from JSClass, but that precludes pure
// compile-time initialization of the form
// |DOMJSInterfaceAndPrototypeClass = {...};|, since C++ only allows brace
// initialization for aggregate/POD types.
JSClass mBase;
// Either eInterface or eInterfacePrototype
DOMObjectType mType;
const NativePropertyHooks* mNativeHooks;
// The value to return for toString() on this interface or interface prototype
// object.
const char* mToString;
const prototypes::ID mPrototypeID;
const uint32_t mDepth;
static const DOMIfaceAndProtoJSClass* FromJSClass(const JSClass* base) {
MOZ_ASSERT(base->flags & JSCLASS_IS_DOMIFACEANDPROTOJSCLASS);
return reinterpret_cast<const DOMIfaceAndProtoJSClass*>(base);
}
static const DOMIfaceAndProtoJSClass* FromJSClass(const js::Class* base) {
return FromJSClass(Jsvalify(base));
}
JSClass* ToJSClass() { return &mBase; }
};
inline bool
HasProtoAndIfaceArray(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 JS::Heap<JSObject*>*
GetProtoAndIfaceArray(JSObject* global)
{
MOZ_ASSERT(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL);
return static_cast<JS::Heap<JSObject*>*>(
js::GetReservedSlot(global, DOM_PROTOTYPE_SLOT).toPrivate());
}
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_DOMJSClass_h */