gecko-dev/js/public/Realm.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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/. */
/*
* Ways to get various per-Realm objects. All the getters declared in this
* header operate on the Realm corresponding to the current compartment on the
* JSContext.
*/
#ifndef js_Realm_h
#define js_Realm_h
#include "jspubtd.h"
#include "js/GCPolicyAPI.h"
#include "js/TypeDecls.h" // forward-declaration of JS::Realm
namespace js {
namespace gc {
JS_PUBLIC_API(void) TraceRealm(JSTracer* trc, JS::Realm* realm, const char* name);
JS_PUBLIC_API(bool) RealmNeedsSweep(JS::Realm* realm);
}
}
namespace JS {
// Each Realm holds a strong reference to its GlobalObject, and vice versa.
template <>
struct GCPolicy<Realm*> : public NonGCPointerPolicy<Realm*>
{
static void trace(JSTracer* trc, Realm** vp, const char* name) {
if (*vp)
::js::gc::TraceRealm(trc, *vp, name);
}
static bool needsSweep(Realm** vp) {
return *vp && ::js::gc::RealmNeedsSweep(*vp);
}
};
// Get the current realm, if any. The ECMAScript spec calls this "the current
// Realm Record".
extern JS_PUBLIC_API(Realm*)
GetCurrentRealmOrNull(JSContext* cx);
namespace shadow {
class Realm
{
protected:
JS::Compartment* compartment_;
explicit Realm(JS::Compartment* comp)
: compartment_(comp)
{}
public:
JS::Compartment* compartment() {
return compartment_;
}
static shadow::Realm* get(JS::Realm* realm) {
return reinterpret_cast<shadow::Realm*>(realm);
}
};
}; // namespace shadow
// Return the compartment that contains a given realm.
inline JS::Compartment*
GetCompartmentForRealm(Realm* realm)
{
return shadow::Realm::get(realm)->compartment();
}
// Return an object's realm. All objects except cross-compartment wrappers are
// created in a particular realm, which never changes. Returns null if obj is
// a cross-compartment wrapper.
extern JS_PUBLIC_API(Realm*)
GetObjectRealmOrNull(JSObject* obj);
// Get the value of the "private data" internal field of the given Realm.
// This field is initially null and is set using SetRealmPrivate.
// It's a pointer to embeddding-specific data that SpiderMonkey never uses.
extern JS_PUBLIC_API(void*)
GetRealmPrivate(Realm* realm);
// Set the "private data" internal field of the given Realm.
extern JS_PUBLIC_API(void)
SetRealmPrivate(Realm* realm, void* data);
typedef void
(* DestroyRealmCallback)(JSFreeOp* fop, Realm* realm);
// Set the callback SpiderMonkey calls just before garbage-collecting a realm.
// Embeddings can use this callback to free private data associated with the
// realm via SetRealmPrivate.
//
// By the time this is called, the global object for the realm has already been
// collected.
extern JS_PUBLIC_API(void)
SetDestroyRealmCallback(JSContext* cx, DestroyRealmCallback callback);
typedef void
(* RealmNameCallback)(JSContext* cx, Handle<Realm*> realm, char* buf, size_t bufsize);
// Set the callback SpiderMonkey calls to get the name of a realm, for
// diagnostic output.
extern JS_PUBLIC_API(void)
SetRealmNameCallback(JSContext* cx, RealmNameCallback callback);
// Get the global object for the given realm. This only returns nullptr during
// GC, between collecting the global object and destroying the Realm.
extern JS_PUBLIC_API(JSObject*)
GetRealmGlobalOrNull(Handle<Realm*> realm);
extern JS_PUBLIC_API(JSObject*)
GetRealmObjectPrototype(JSContext* cx);
extern JS_PUBLIC_API(JSObject*)
GetRealmFunctionPrototype(JSContext* cx);
extern JS_PUBLIC_API(JSObject*)
GetRealmArrayPrototype(JSContext* cx);
extern JS_PUBLIC_API(JSObject*)
GetRealmErrorPrototype(JSContext* cx);
extern JS_PUBLIC_API(JSObject*)
GetRealmIteratorPrototype(JSContext* cx);
} // namespace JS
#endif // js_Realm_h