gecko-dev/dom/abort/AbortFollower.h

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2.7 KiB
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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_AbortFollower_h
#define mozilla_dom_AbortFollower_h
#include "jsapi.h"
#include "nsISupportsImpl.h"
#include "nsTObserverArray.h"
#include "mozilla/WeakPtr.h"
namespace mozilla {
namespace dom {
class AbortSignal;
class AbortSignalImpl;
// This class must be implemented by objects who want to follow an
// AbortSignalImpl.
class AbortFollower : public nsISupports {
public:
virtual void RunAbortAlgorithm() = 0;
// This adds strong reference to this follower on the signal, which means
// you'll need to call Unfollow() to prevent your object from living
// needlessly longer.
void Follow(AbortSignalImpl* aSignal);
// Explicitly call this to let garbage collection happen sooner when the
// follower finished its work and cannot be aborted anymore.
void Unfollow();
bool IsFollowing() const;
AbortSignalImpl* Signal() const { return mFollowingSignal; }
protected:
virtual ~AbortFollower();
friend class AbortSignalImpl;
WeakPtr<AbortSignalImpl> mFollowingSignal;
};
class AbortSignalImpl : public nsISupports, public SupportsWeakPtr {
public:
explicit AbortSignalImpl(bool aAborted, JS::Handle<JS::Value> aReason);
bool Aborted() const;
// Web IDL Layer
void GetReason(JSContext* aCx, JS::MutableHandle<JS::Value> aReason);
// Helper for other DOM code
JS::Value RawReason() const;
virtual void SignalAbort(JS::Handle<JS::Value> aReason);
protected:
// Subclasses of this class must call these Traverse and Unlink functions
// during corresponding cycle collection operations.
static void Traverse(AbortSignalImpl* aSignal,
nsCycleCollectionTraversalCallback& cb);
static void Unlink(AbortSignalImpl* aSignal);
virtual ~AbortSignalImpl() { UnlinkFollowers(); }
JS::Heap<JS::Value> mReason;
private:
friend class AbortFollower;
void MaybeAssignAbortError(JSContext* aCx);
void UnlinkFollowers();
// Raw pointers. |AbortFollower::Follow| adds to this array, and
// |AbortFollower::Unfollow| (also called by the destructor) will remove
// from this array. Finally, calling |SignalAbort()| will (after running all
// abort algorithms) empty this and make all contained followers |Unfollow()|.
nsTObserverArray<RefPtr<AbortFollower>> mFollowers;
bool mAborted;
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_AbortFollower_h