gecko-dev/dom/bindings/DOMJSClass.h

348 lines
12 KiB
C++

/* -*- 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_DOMJSClass_h
#define mozilla_dom_DOMJSClass_h
#include "jsfriendapi.h"
#include "mozilla/Assertions.h"
#include "mozilla/dom/PrototypeList.h" // auto-generated
#include "mozilla/dom/JSSlots.h"
class nsCycleCollectionParticipant;
// All DOM globals must have a slot at DOM_PROTOTYPE_SLOT.
#define DOM_PROTOTYPE_SLOT JSCLASS_GLOBAL_SLOT_COUNT
// Keep this count up to date with any extra global slots added above.
#define DOM_GLOBAL_SLOTS 1
// We use these flag bits for the new bindings.
#define JSCLASS_DOM_GLOBAL JSCLASS_USERBIT1
#define JSCLASS_IS_DOMIFACEANDPROTOJSCLASS JSCLASS_USERBIT2
namespace mozilla {
namespace dom {
typedef bool
(* ResolveOwnProperty)(JSContext* cx, JS::Handle<JSObject*> wrapper,
JS::Handle<JSObject*> obj, JS::Handle<jsid> id,
JS::MutableHandle<JSPropertyDescriptor> desc);
typedef bool
(* EnumerateOwnProperties)(JSContext* cx, JS::Handle<JSObject*> wrapper,
JS::Handle<JSObject*> obj,
JS::AutoIdVector& props);
// Returns true if aObj's global has any of the permissions named in
// aPermissions set to nsIPermissionManager::ALLOW_ACTION. aPermissions must be
// null-terminated.
bool
CheckAnyPermissions(JSContext* aCx, JSObject* aObj, const char* const aPermissions[]);
// Returns true if aObj's global has all of the permissions named in
// aPermissions set to nsIPermissionManager::ALLOW_ACTION. aPermissions must be
// null-terminated.
bool
CheckAllPermissions(JSContext* aCx, JSObject* aObj, const char* const aPermissions[]);
// Returns true if the given global is of a type whose bit is set in
// aNonExposedGlobals.
bool
IsNonExposedGlobal(JSContext* aCx, JSObject* aGlobal,
uint32_t aNonExposedGlobals);
struct ConstantSpec
{
const char* name;
JS::Value value;
};
typedef bool (*PropertyEnabled)(JSContext* cx, JSObject* global);
namespace GlobalNames {
// The names of our possible globals. These are the names of the actual
// interfaces, not of the global names used to refer to them in IDL [Exposed]
// annotations.
static const uint32_t Window = 1u << 0;
static const uint32_t BackstagePass = 1u << 1;
static const uint32_t DedicatedWorkerGlobalScope = 1u << 2;
static const uint32_t SharedWorkerGlobalScope = 1u << 3;
static const uint32_t ServiceWorkerGlobalScope = 1u << 4;
static const uint32_t WorkerDebuggerGlobalScope = 1u << 5;
} // namespace GlobalNames
template<typename T>
struct Prefable {
inline bool isEnabled(JSContext* cx, JS::Handle<JSObject*> obj) const {
// Reading "enabled" on a worker thread is technically undefined behavior,
// because it's written only on main threads, with no barriers of any sort.
// So we want to avoid doing that. But we don't particularly want to make
// expensive NS_IsMainThread calls here.
//
// The good news is that "enabled" is only written for things that have a
// Pref annotation, and such things can never be exposed on non-Window
// globals; our IDL parser enforces that. So as long as we check our
// exposure set before checking "enabled" we will be ok.
if (nonExposedGlobals &&
IsNonExposedGlobal(cx, js::GetGlobalForObjectCrossCompartment(obj),
nonExposedGlobals)) {
return false;
}
if (!enabled) {
return false;
}
if (!enabledFunc && !availableFunc && !checkAnyPermissions && !checkAllPermissions) {
return true;
}
if (enabledFunc &&
!enabledFunc(cx, js::GetGlobalForObjectCrossCompartment(obj))) {
return false;
}
if (availableFunc &&
!availableFunc(cx, js::GetGlobalForObjectCrossCompartment(obj))) {
return false;
}
if (checkAnyPermissions &&
!CheckAnyPermissions(cx, js::GetGlobalForObjectCrossCompartment(obj),
checkAnyPermissions)) {
return false;
}
if (checkAllPermissions &&
!CheckAllPermissions(cx, js::GetGlobalForObjectCrossCompartment(obj),
checkAllPermissions)) {
return false;
}
return true;
}
// A boolean indicating whether this set of specs is enabled
bool enabled;
// Bitmask of global names that we should not be exposed in.
uint32_t nonExposedGlobals;
// 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 unless availableFunc overrides.
PropertyEnabled enabledFunc;
// A function pointer to a function that can be used to disable a
// property even if "enabled" is true and enabledFunc allowed. This
// is basically a hack to avoid having to codegen PropertyEnabled
// implementations in case when we need to do two separate checks.
PropertyEnabled availableFunc;
const char* const* checkAnyPermissions;
const char* const* checkAllPermissions;
// 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* staticMethodSpecs;
const Prefable<const JSPropertySpec>* staticAttributes;
jsid* staticAttributeIds;
const JSPropertySpec* staticAttributeSpecs;
const Prefable<const JSFunctionSpec>* methods;
jsid* methodIds;
const JSFunctionSpec* methodSpecs;
const Prefable<const JSPropertySpec>* attributes;
jsid* attributeIds;
const JSPropertySpec* attributeSpecs;
const Prefable<const JSFunctionSpec>* unforgeableMethods;
jsid* unforgeableMethodIds;
const JSFunctionSpec* unforgeableMethodSpecs;
const Prefable<const JSPropertySpec>* unforgeableAttributes;
jsid* unforgeableAttributeIds;
const JSPropertySpec* unforgeableAttributeSpecs;
const Prefable<const ConstantSpec>* constants;
jsid* constantIds;
const ConstantSpec* constantSpecs;
// Index into methods for the entry that is [Alias="@@iterator"], -1 if none
int32_t iteratorAliasMethodIndex;
};
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 (for
// ShimInterfaceInfo).
const NativePropertyHooks* mProtoHooks;
};
enum DOMObjectType {
eInstance,
eGlobalInstance,
eInterface,
eInterfacePrototype,
eGlobalInterfacePrototype,
eNamedPropertiesObject
};
inline
bool
IsInstance(DOMObjectType type)
{
return type == eInstance || type == eGlobalInstance;
}
inline
bool
IsInterfacePrototype(DOMObjectType type)
{
return type == eInterfacePrototype || type == eGlobalInterfacePrototype;
}
typedef JSObject* (*ParentGetter)(JSContext* aCx, JS::Handle<JSObject*> aObj);
typedef JSObject* (*ProtoGetter)(JSContext* aCx,
JS::Handle<JSObject*> aGlobal);
/**
* 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*> (*ProtoHandleGetter)(JSContext* aCx,
JS::Handle<JSObject*> aGlobal);
// 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.
const js::Class mBase;
// 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;
ProtoHandleGetter mGetProto;
// This stores the CC participant for the native, null if this class does not
// implement cycle collection or if it inherits from nsISupports (we can get
// the CC participant by QI'ing in that case).
nsCycleCollectionParticipant* mParticipant;
static const DOMJSClass* FromJSClass(const JSClass* base) {
MOZ_ASSERT(base->flags & JSCLASS_IS_DOMJSCLASS);
return reinterpret_cast<const DOMJSClass*>(base);
}
static const DOMJSClass* FromJSClass(const js::Class* base) {
return FromJSClass(Jsvalify(base));
}
const JSClass* ToJSClass() const { return Jsvalify(&mBase); }
};
// Special JSClass for DOM interface and interface prototype objects.
struct DOMIfaceAndProtoJSClass
{
// It would be nice to just inherit from js::Class, but that precludes pure
// compile-time initialization of the form
// |DOMJSInterfaceAndPrototypeClass = {...};|, since C++ only allows brace
// initialization for aggregate/POD types.
const js::Class mBase;
// Either eInterface, eInterfacePrototype, eGlobalInterfacePrototype or
// eNamedPropertiesObject.
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;
ProtoGetter mGetParentProto;
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));
}
const JSClass* ToJSClass() const { return Jsvalify(&mBase); }
};
class ProtoAndIfaceCache;
inline bool
HasProtoAndIfaceCache(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 ProtoAndIfaceCache*
GetProtoAndIfaceCache(JSObject* global)
{
MOZ_ASSERT(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL);
return static_cast<ProtoAndIfaceCache*>(
js::GetReservedSlot(global, DOM_PROTOTYPE_SLOT).toPrivate());
}
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_DOMJSClass_h */