/* -*- 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_StorageManager_h

#define mozilla_dom_StorageManager_h

#include "nsIDOMStorageManager.h"

#include "StorageObserver.h"

#include "LocalStorage.h"

#include "LocalStorageCache.h"

#include "mozilla/dom/Storage.h"

#include "nsTHashtable.h"

#include "nsDataHashtable.h"

#include "nsClassHashtable.h"

#include "nsHashKeys.h"

namespace mozilla {

class OriginAttributesPattern;

namespace dom {

class LocalStorageManager final : public nsIDOMStorageManager

                                , public StorageObserverSink

{

  NS_DECL_ISUPPORTS

  NS_DECL_NSIDOMSTORAGEMANAGER

public:

  LocalStorageManager();

  // Reads the preference for DOM storage quota

  static uint32_t GetQuota();

  // Gets (but not ensures) cache for the given scope

  LocalStorageCache* GetCache(const nsACString& aOriginSuffix,

                              const nsACString& aOriginNoSuffix);

  // Returns object keeping usage cache for the scope.

  already_AddRefed<StorageUsage>

  GetOriginUsage(const nsACString& aOriginNoSuffix);

  static nsAutoCString CreateOrigin(const nsACString& aOriginSuffix,

                                    const nsACString& aOriginNoSuffix);

private:

  ~LocalStorageManager();

  // StorageObserverSink, handler to various chrome clearing notification

  nsresult Observe(const char* aTopic,

                   const nsAString& aOriginAttributesPattern,

                   const nsACString& aOriginScope) override;

  // Since nsTHashtable doesn't like multiple inheritance, we have to aggregate

  // LocalStorageCache into the entry.

  class LocalStorageCacheHashKey : public nsCStringHashKey

  {

  public:

    explicit LocalStorageCacheHashKey(const nsACString* aKey)

      : nsCStringHashKey(aKey)

      , mCache(new LocalStorageCache(aKey))

    {}

    LocalStorageCacheHashKey(LocalStorageCacheHashKey&& aOther)

      : nsCStringHashKey(std::move(aOther))

      , mCache(std::move(aOther.mCache))

      , mCacheRef(std::move(aOther.mCacheRef))

    {

      NS_ERROR("Shouldn't be called");

    }

    LocalStorageCache* cache() { return mCache; }

    // Keep the cache referenced forever, used for sessionStorage.

    void HardRef() { mCacheRef = mCache; }

  private:

    // weak ref only since cache references its manager.

    LocalStorageCache* mCache;

    // hard ref when this is sessionStorage to keep it alive forever.

    RefPtr<LocalStorageCache> mCacheRef;

  };

  // Ensures cache for a scope, when it doesn't exist it is created and

  // initalized, this also starts preload of persistent data.

  already_AddRefed<LocalStorageCache> PutCache(const nsACString& aOriginSuffix,

                                               const nsACString& aOriginNoSuffix,

                                               nsIPrincipal* aPrincipal);

  enum class CreateMode {

    // GetStorage: do not create if it's not already in memory.

    UseIfExistsNeverCreate,

    // CreateStorage: Create it if it's not already in memory.

    CreateAlways,

    // PrecacheStorage: Create only if the database says we ShouldPreloadOrigin.

    CreateIfShouldPreload

  };

  // Helper for creation of DOM storage objects

  nsresult GetStorageInternal(CreateMode aCreate,

                              mozIDOMWindow* aWindow,

                              nsIPrincipal* aPrincipal,

                              const nsAString& aDocumentURI,

                              bool aPrivate,

                              Storage** aRetval);

  // Suffix->origin->cache map

  typedef nsTHashtable<LocalStorageCacheHashKey> CacheOriginHashtable;

  nsClassHashtable<nsCStringHashKey, CacheOriginHashtable> mCaches;

  void ClearCaches(uint32_t aUnloadFlags,

                   const OriginAttributesPattern& aPattern,

                   const nsACString& aKeyPrefix);

  // Global getter of localStorage manager service

  static LocalStorageManager* Self() { return sSelf; }

  // Like Self, but creates an instance if we're not yet initialized.

  static LocalStorageManager* Ensure();

private:

  // Keeps usage cache objects for eTLD+1 scopes we have touched.

  nsDataHashtable<nsCStringHashKey, RefPtr<StorageUsage> > mUsages;

  friend class LocalStorageCache;

  friend class StorageDBChild;

  // Releases cache since it is no longer referrered by any Storage object.

  virtual void DropCache(LocalStorageCache* aCache);

  static LocalStorageManager* sSelf;

};

} // namespace dom

} // namespace mozilla

#endif // mozilla_dom_StorageManager_h