/* -*- 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_cache_Action_h #define mozilla_dom_cache_Action_h #include "mozilla/Atomics.h" #include "mozilla/dom/cache/Types.h" #include "nsISupportsImpl.h" class mozIStorageConnection; namespace mozilla { namespace dom { namespace cache { class Action { public: class Resolver { public: // 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; NS_IMETHOD_(MozExternalRefCountType) AddRef(void) = 0; NS_IMETHOD_(MozExternalRefCountType) Release(void) = 0; }; // 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 { public: virtual mozIStorageConnection* GetConnection() const = 0; virtual void SetConnection(mozIStorageConnection* aConn) = 0; }; // 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(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; } NS_INLINE_DECL_REFCOUNTING(cache::Action) protected: Action(); // virtual because deleted through base class pointer virtual ~Action(); // Check if this Action has been canceled. May be called from any thread, // but typically used from the target thread. bool IsCanceled() const; private: // Accessible from any thread. Atomic<bool> mCanceled; }; } // namespace cache } // namespace dom } // namespace mozilla #endif // mozilla_dom_cache_Action_h