// Copyright (c) 2012 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 WEBKIT_DOM_STORAGE_DOM_STORAGE_CONTEXT_H_ #define WEBKIT_DOM_STORAGE_DOM_STORAGE_CONTEXT_H_ #pragma once #include #include "base/atomic_sequence_num.h" #include "base/basictypes.h" #include "base/file_path.h" #include "base/memory/ref_counted.h" #include "base/observer_list.h" class FilePath; class GURL; class NullableString16; namespace base { class Time; } namespace quota { class SpecialStoragePolicy; } namespace dom_storage { class DomStorageArea; class DomStorageNamespace; class DomStorageSession; class DomStorageTaskRunner; // The Context is the root of an object containment hierachy for // Namespaces and Areas related to the owning profile. // One instance is allocated in the main process for each profile, // instance methods should be called serially in the background as // determined by the task_runner. Specifcally not on chrome's non-blocking // IO thread since these methods can result in blocking file io. // // In general terms, the DomStorage object relationships are... // Contexts (per-profile) own Namespaces which own Areas which share Maps. // Hosts(per-renderer) refer to Namespaces and Areas open in it's renderer. // Sessions (per-tab) cause the creation and deletion of session Namespaces. // // Session Namespaces are cloned by initially making a shallow copy of // all contained Areas, the shallow copies refer to the same refcounted Map, // and does a deep copy-on-write if needed. // // Classes intended to be used by an embedder are DomStorageContext, // DomStorageHost, and DomStorageSession. The other classes are for // internal consumption. class DomStorageContext : public base::RefCountedThreadSafe { public: // An interface for observing LocalStorage events on the // background thread. class EventObserver { public: virtual void OnDomStorageItemSet( const DomStorageArea* area, const string16& key, const string16& new_value, const NullableString16& old_value, // may be null on initial insert const GURL& page_url) = 0; virtual void OnDomStorageItemRemoved( const DomStorageArea* area, const string16& key, const string16& old_value, const GURL& page_url) = 0; virtual void OnDomStorageAreaCleared( const DomStorageArea* area, const GURL& page_url) = 0; virtual ~EventObserver() {} }; DomStorageContext(const FilePath& directory, // empty for incognito profiles quota::SpecialStoragePolicy* special_storage_policy, DomStorageTaskRunner* task_runner); DomStorageTaskRunner* task_runner() const { return task_runner_; } DomStorageNamespace* GetStorageNamespace(int64 namespace_id); // Methods to add, remove, and notify EventObservers. void AddEventObserver(EventObserver* observer); void RemoveEventObserver(EventObserver* observer); void NotifyItemSet( const DomStorageArea* area, const string16& key, const string16& new_value, const NullableString16& old_value, const GURL& page_url); void NotifyItemRemoved( const DomStorageArea* area, const string16& key, const string16& old_value, const GURL& page_url); void NotifyAreaCleared( const DomStorageArea* area, const GURL& page_url); private: friend class DomStorageSession; friend class base::RefCountedThreadSafe; typedef std::map > StorageNamespaceMap; ~DomStorageContext(); // May be called on any thread. int64 AllocateSessionId() { return session_id_sequence_.GetNext(); } // Must be called on the background thread. void CreateSessionNamespace(int64 namespace_id); void DeleteSessionNamespace(int64 namespace_id); void CloneSessionNamespace(int64 existing_id, int64 new_id); // Collection of namespaces keyed by id. StorageNamespaceMap namespaces_; // Where localstorage data is stored, maybe empty for the incognito use case. FilePath directory_; // Used to schedule sequenced background tasks. scoped_refptr task_runner_; // List of objects observing local storage events. ObserverList event_observers_; // We use a 32 bit identifier for per tab storage sessions. // At a tab per second, this range is large enough for 68 years. base::AtomicSequenceNumber session_id_sequence_; }; } // namespace dom_storage #endif // WEBKIT_DOM_STORAGE_DOM_STORAGE_CONTEXT_H_