gecko-dev/dom/bindings/SpiderMonkeyInterface.h

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/* -*- 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_SpiderMonkeyInterface_h
#define mozilla_dom_SpiderMonkeyInterface_h
#include "jsapi.h"
#include "js/RootingAPI.h"
#include "js/TracingAPI.h"
namespace mozilla::dom {
/*
* Class that just handles the JSObject storage and tracing for spidermonkey
* interfaces
*/
struct SpiderMonkeyInterfaceObjectStorage {
protected:
JSObject* mImplObj;
JSObject* mWrappedObj;
SpiderMonkeyInterfaceObjectStorage()
: mImplObj(nullptr), mWrappedObj(nullptr) {}
SpiderMonkeyInterfaceObjectStorage(
SpiderMonkeyInterfaceObjectStorage&& aOther)
: mImplObj(aOther.mImplObj), mWrappedObj(aOther.mWrappedObj) {
aOther.mImplObj = nullptr;
aOther.mWrappedObj = nullptr;
}
public:
inline void TraceSelf(JSTracer* trc) {
JS::TraceRoot(trc, &mImplObj,
"SpiderMonkeyInterfaceObjectStorage.mImplObj");
JS::TraceRoot(trc, &mWrappedObj,
"SpiderMonkeyInterfaceObjectStorage.mWrappedObj");
}
inline bool inited() const { return !!mImplObj; }
inline bool WrapIntoNewCompartment(JSContext* cx) {
return JS_WrapObject(
cx, JS::MutableHandle<JSObject*>::fromMarkedLocation(&mWrappedObj));
}
inline JSObject* Obj() const {
MOZ_ASSERT(inited());
return mWrappedObj;
}
private:
SpiderMonkeyInterfaceObjectStorage(
const SpiderMonkeyInterfaceObjectStorage&) = delete;
};
// A class for rooting an existing SpiderMonkey Interface struct
template <typename InterfaceType>
class MOZ_RAII SpiderMonkeyInterfaceRooter : private JS::CustomAutoRooter {
public:
template <typename CX>
SpiderMonkeyInterfaceRooter(const CX& cx, InterfaceType* aInterface)
: JS::CustomAutoRooter(cx), mInterface(aInterface) {}
virtual void trace(JSTracer* trc) override { mInterface->TraceSelf(trc); }
private:
SpiderMonkeyInterfaceObjectStorage* const mInterface;
};
// And a specialization for dealing with nullable SpiderMonkey interfaces
template <typename Inner>
struct Nullable;
template <typename InterfaceType>
class MOZ_RAII SpiderMonkeyInterfaceRooter<Nullable<InterfaceType>>
: private JS::CustomAutoRooter {
public:
template <typename CX>
SpiderMonkeyInterfaceRooter(const CX& cx, Nullable<InterfaceType>* aInterface)
: JS::CustomAutoRooter(cx), mInterface(aInterface) {}
virtual void trace(JSTracer* trc) override {
if (!mInterface->IsNull()) {
mInterface->Value().TraceSelf(trc);
}
}
private:
Nullable<InterfaceType>* const mInterface;
};
// Class for easily setting up a rooted SpiderMonkey interface object on the
// stack
template <typename InterfaceType>
class MOZ_RAII RootedSpiderMonkeyInterface final
: public InterfaceType,
private SpiderMonkeyInterfaceRooter<InterfaceType> {
public:
template <typename CX>
explicit RootedSpiderMonkeyInterface(const CX& cx)
: InterfaceType(), SpiderMonkeyInterfaceRooter<InterfaceType>(cx, this) {}
template <typename CX>
RootedSpiderMonkeyInterface(const CX& cx, JSObject* obj)
: InterfaceType(obj),
SpiderMonkeyInterfaceRooter<InterfaceType>(cx, this) {}
};
} // namespace mozilla::dom
#endif /* mozilla_dom_SpiderMonkeyInterface_h */