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 "jsfriendapi.h"
#include "js/TracingAPI.h"
namespace mozilla {
namespace 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::UnsafeTraceRoot(trc, &mImplObj, "SpiderMonkeyInterfaceObjectStorage.mImplObj");
JS::UnsafeTraceRoot(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 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
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 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
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 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: InterfaceType(),
SpiderMonkeyInterfaceRooter<InterfaceType>(cx, this
MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
{
}
template <typename CX>
RootedSpiderMonkeyInterface(const CX& cx, JSObject* obj MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: InterfaceType(obj),
SpiderMonkeyInterfaceRooter<InterfaceType>(cx, this
MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
{
}
};
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_SpiderMonkeyInterface_h */