content/browser/dom_storage/dom_storage_host.h

// Copyright 2013 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 CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_HOST_H_
#define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_HOST_H_

#include <map>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/optional.h"
#include "base/strings/nullable_string16.h"
#include "base/strings/string16.h"
#include "content/browser/bad_message.h"
#include "content/common/content_export.h"
#include "content/common/dom_storage/dom_storage_types.h"

class GURL;

namespace url {
class Origin;
}

namespace content {

class DOMStorageContextImpl;
class DOMStorageHost;
class DOMStorageNamespace;
class DOMStorageArea;

// One instance is allocated in the main process for each client process.
// Used by DOMStorageMessageFilter in Chrome.
// This class is single threaded, and performs blocking file reads/writes,
// so it shouldn't be used on chrome's IO thread.
// See class comments for DOMStorageContextImpl for a larger overview.
class CONTENT_EXPORT DOMStorageHost {
 public:
  explicit DOMStorageHost(DOMStorageContextImpl* context);
  ~DOMStorageHost();

  base::Optional<bad_message::BadMessageReason> OpenStorageArea(
      int connection_id,
      const std::string& namespace_id,
      const url::Origin& origin);
  void CloseStorageArea(int connection_id);
  bool ExtractAreaValues(int connection_id, DOMStorageValuesMap* map);
  unsigned GetAreaLength(int connection_id);
  base::NullableString16 GetAreaKey(int connection_id, unsigned index);
  base::NullableString16 GetAreaItem(int connection_id,
                                     const base::string16& key);
  bool SetAreaItem(int connection_id,
                   const base::string16& key,
                   const base::string16& value,
                   const base::NullableString16& client_old_value,
                   const GURL& page_url);
  bool RemoveAreaItem(int connection_id,
                      const base::string16& key,
                      const base::NullableString16& client_old_value,
                      const GURL& page_url);
  bool ClearArea(int connection_id, const GURL& page_url);
  bool HasAreaOpen(const std::string& namespace_id,
                   const url::Origin& origin) const;
  bool HasConnection(int connection_id) const {
    return !!GetOpenArea(connection_id);
  }

 private:
  // Struct to hold references needed for areas that are open
  // within our associated client process.
  struct NamespaceAndArea {
    scoped_refptr<DOMStorageNamespace> namespace_;
    scoped_refptr<DOMStorageArea> area_;
    NamespaceAndArea();
    NamespaceAndArea(const NamespaceAndArea& other);
    ~NamespaceAndArea();
  };
  typedef std::map<int, NamespaceAndArea > AreaMap;

  DOMStorageArea* GetOpenArea(int connection_id) const;
  DOMStorageNamespace* GetNamespace(int connection_id) const;

  scoped_refptr<DOMStorageContextImpl> context_;
  AreaMap connections_;
  std::map<DOMStorageArea*, int> areas_open_count_;

  DISALLOW_COPY_AND_ASSIGN(DOMStorageHost);
};

}  // namespace content

#endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_HOST_H_