mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-25 13:51:41 +00:00
65 lines
1.9 KiB
C++
65 lines
1.9 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/. */
|
|
|
|
/**
|
|
* An implementation of Rooted for OwningNonNull<T>. This works by assuming
|
|
* that T has a Trace() method defined on it which will trace whatever things
|
|
* inside the T instance need tracing.
|
|
*
|
|
* This implementation has one serious drawback: operator= doesn't work right
|
|
* because it's declared on Rooted directly and expects the type Rooted is
|
|
* templated over.
|
|
*/
|
|
|
|
#ifndef mozilla_RootedOwningNonNull_h__
|
|
#define mozilla_RootedOwningNonNull_h__
|
|
|
|
#include "mozilla/OwningNonNull.h"
|
|
#include "js/GCPolicyAPI.h"
|
|
#include "js/RootingAPI.h"
|
|
|
|
namespace JS {
|
|
template<typename T>
|
|
struct GCPolicy<mozilla::OwningNonNull<T>>
|
|
{
|
|
typedef mozilla::OwningNonNull<T> SmartPtrType;
|
|
|
|
static SmartPtrType initial()
|
|
{
|
|
return SmartPtrType();
|
|
}
|
|
|
|
static void trace(JSTracer* trc, SmartPtrType* tp,
|
|
const char* name)
|
|
{
|
|
// We have to be very careful here. Normally, OwningNonNull can't be null.
|
|
// But binding code can end up in a situation where it sets up a
|
|
// Rooted<OwningNonNull> and then before it gets a chance to assign to it
|
|
// (e.g. from the constructor of the thing being assigned) a GC happens. So
|
|
// we can land here when *tp stores a null pointer because it's not
|
|
// initialized.
|
|
//
|
|
// So we need to check for that before jumping.
|
|
if ((*tp).isInitialized()) {
|
|
(*tp)->Trace(trc);
|
|
}
|
|
}
|
|
};
|
|
} // namespace JS
|
|
|
|
namespace js {
|
|
template<typename T, typename Wrapper>
|
|
struct WrappedPtrOperations<mozilla::OwningNonNull<T>, Wrapper>
|
|
{
|
|
operator T& () const
|
|
{
|
|
return static_cast<const Wrapper*>(this)->get();
|
|
}
|
|
};
|
|
} // namespace js
|
|
|
|
#endif /* mozilla_RootedOwningNonNull_h__ */
|