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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 */
#ifndef mozilla_dom_cache_Action_h
#define mozilla_dom_cache_Action_h
#include "mozilla/Atomics.h"
#include "mozilla/dom/cache/Types.h"
#include "mozilla/dom/SafeRefPtr.h"
#include "nsISupportsImpl.h"
class mozIStorageConnection;
namespace mozilla {
namespace dom {
namespace cache {
class Action : public SafeRefCounted<Action> {
class Resolver {
Resolver& operator=(const Resolver& aRHS) = delete;
// Note: Action must drop Resolver ref after calling Resolve()!
// Note: Must be called on the same thread used to execute
// Action::RunOnTarget().
virtual void Resolve(nsresult aRv) = 0;
inline SafeRefPtr<Action::Resolver> SafeRefPtrFromThis() {
return SafeRefPtr<Action::Resolver>{this, AcquireStrongRefFromRawPtr{}};
// Class containing data that can be opportunistically shared between
// multiple Actions running on the same thread/Context. In theory
// this could be abstracted to a generic key/value map, but for now
// just explicitly provide accessors for the data we need.
class Data {
virtual mozIStorageConnection* GetConnection() const = 0;
virtual void SetConnection(mozIStorageConnection* aConn) = 0;
// virtual because deleted through base class pointer
virtual ~Action();
// Execute operations on the target thread. Once complete call
// Resolver::Resolve(). This can be done sync or async.
// Note: Action should hold Resolver ref until its ready to call Resolve().
// Note: The "target" thread is determined when the Action is scheduled on
// Context. The Action should not assume any particular thread is used.
virtual void RunOnTarget(SafeRefPtr<Resolver> aResolver,
const QuotaInfo& aQuotaInfo,
Data* aOptionalData) = 0;
// Called on initiating thread when the Action is canceled. The Action is
// responsible for calling Resolver::Resolve() as normal; either with a
// normal error code or NS_ERROR_ABORT. If CancelOnInitiatingThread() is
// called after Resolve() has already occurred, then the cancel can be
// ignored.
// Cancellation is a best effort to stop processing as soon as possible, but
// does not guarantee the Action will not run.
// CancelOnInitiatingThread() may be called more than once. Subsequent
// calls should have no effect.
// Default implementation sets an internal cancellation flag that can be
// queried with IsCanceled().
virtual void CancelOnInitiatingThread();
// Executed on the initiating thread and is passed the nsresult given to
// Resolver::Resolve().
virtual void CompleteOnInitiatingThread(nsresult aRv) {}
// Executed on the initiating thread. If this Action will operate on the
// given cache ID then override this to return true.
virtual bool MatchesCacheId(CacheId aCacheId) const { return false; }
// Check if this Action has been canceled. May be called from any thread,
// but typically used from the target thread.
bool IsCanceled() const;
// Accessible from any thread.
Atomic<bool> mCanceled;
} // namespace cache
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_cache_Action_h