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// 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 <map>
#include <vector>
#include "base/atomic_sequence_num.h"
#include "base/basictypes.h"
#include "base/file_path.h"
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/observer_list.h"
#include "base/time.h"
#include "googleurl/src/gurl.h"
class FilePath;
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 its 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<DomStorageContext> {
public:
struct UsageInfo {
GURL origin;
size_t data_size;
base::Time last_modified;
UsageInfo();
~UsageInfo();
};
// 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& localstorage_directory, // empty for incognito profiles
const FilePath& sessionstorage_directory, // empty for incognito profiles
quota::SpecialStoragePolicy* special_storage_policy,
DomStorageTaskRunner* task_runner);
// Returns the directory path for localStorage, or an empty directory, if
// there is no backing on disk.
const FilePath& localstorage_directory() { return localstorage_directory_; }
// Returns the directory path for sessionStorage, or an empty directory, if
// there is no backing on disk.
const FilePath& sessionstorage_directory() {
return sessionstorage_directory_;
}
DomStorageTaskRunner* task_runner() const { return task_runner_; }
DomStorageNamespace* GetStorageNamespace(int64 namespace_id);
void GetUsageInfo(std::vector<UsageInfo>* infos, bool include_file_info);
void DeleteOrigin(const GURL& origin);
void DeleteDataModifiedSince(const base::Time& cutoff);
void PurgeMemory();
// Used by content settings to alter the behavior around
// what data to keep and what data to discard at shutdown.
// The policy is not so straight forward to describe, see
// the implementation for details.
void SetClearLocalState(bool clear_local_state) {
clear_local_state_ = clear_local_state;
}
void SaveSessionState() {
save_session_state_ = true;
}
// Called when the owning BrowserContext is ending.
// Schedules the commit of any unsaved changes and will delete
// and keep data on disk per the content settings and special storage
// policies. Contained areas and namespaces will stop functioning after
// this method has been called.
void Shutdown();
// 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);
// 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);
private:
friend class DomStorageContextTest;
FRIEND_TEST_ALL_PREFIXES(DomStorageContextTest, Basics);
friend class base::RefCountedThreadSafe<DomStorageContext>;
typedef std::map<int64, scoped_refptr<DomStorageNamespace> >
StorageNamespaceMap;
~DomStorageContext();
void ClearLocalStateInCommitSequence();
// Collection of namespaces keyed by id.
StorageNamespaceMap namespaces_;
// Where localstorage data is stored, maybe empty for the incognito use case.
FilePath localstorage_directory_;
// Where sessionstorage data is stored, maybe empty for the incognito use
// case. Always empty until the file-backed session storage feature is
// implemented.
FilePath sessionstorage_directory_;
// Used to schedule sequenced background tasks.
scoped_refptr<DomStorageTaskRunner> task_runner_;
// List of objects observing local storage events.
ObserverList<EventObserver> 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_;
bool is_shutdown_;
bool clear_local_state_;
bool save_session_state_;
scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy_;
};
} // namespace dom_storage
#endif // WEBKIT_DOM_STORAGE_DOM_STORAGE_CONTEXT_H_
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