// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef EXTENSIONS_BROWSER_API_STORAGE_VALUE_STORE_CACHE_H_
#define EXTENSIONS_BROWSER_API_STORAGE_VALUE_STORE_CACHE_H_
#include <string>
#include "base/callback.h"
#include "base/memory/ref_counted.h"
class ValueStore;
namespace extensions {
class Extension;
// Each namespace of the storage API implements this interface.
// Instances are created on the UI thread, but from then on live on the FILE
// thread. At shutdown, ShutdownOnUI() is first invoked on the UI thread, and
// the destructor is invoked soon after on the FILE thread. This gives
// implementations the chance to work with ValueStores on FILE but observe
// events on UI.
// It also means that any methods invoked on UI *before ShutdownOnUI()* can
// safely post other methods to the FILE thread, since the deletion task is only
// posted to FILE after ShutdownOnUI().
class ValueStoreCache {
public:
typedef base::Callback<void(ValueStore*)> StorageCallback;
// Invoked on FILE.
virtual ~ValueStoreCache();
// This is invoked from the UI thread during destruction of the Profile that
// ultimately owns this object. Any Profile-related cleanups should be
// performed in this method, since the destructor will execute later, after
// the Profile is already gone.
virtual void ShutdownOnUI();
// Requests the cache to invoke |callback| with the appropriate ValueStore
// for the given |extension|. |callback| should be invoked with a NULL
// ValueStore in case of errors.
// |extension| is passed in a scoped_refptr<> because this method is
// asynchronously posted as a task to the loop returned by GetMessageLoop(),
// and this guarantees the Extension is still valid when the method executes.
virtual void RunWithValueStoreForExtension(
const StorageCallback& callback,
scoped_refptr<const Extension> extension) = 0;
// Requests the cache to delete any storage used by |extension_id|.
virtual void DeleteStorageSoon(const std::string& extension_id) = 0;
};
} // namespace extensions
#endif // EXTENSIONS_BROWSER_API_STORAGE_VALUE_STORE_CACHE_H_