Quelle LocalStorageCache.h Sprache: C

/* -*- 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_LocalStorageCache_h
#define mozilla_dom_LocalStorageCache_h

#include "nsIPrincipal.h"

#include "nsString.h"
#include "nsTHashMap.h"
#include "nsHashKeys.h"
#include "mozilla/Monitor.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Atomics.h"

namespace mozilla::dom {

class LocalStorage;
class LocalStorageCacheChild;
class LocalStorageManager;
class StorageUsage;
class StorageDBBridge;

// Interface class on which only the database or IPC may call.
// Used to populate the cache with DB data.
class LocalStorageCacheBridge {
public:
  NS_IMETHOD_(MozExternalRefCountType) AddRef(void);
  NS_IMETHOD_(void) Release(void);

  // The origin of the cache, result is concatenation of OriginNoSuffix() and
  // OriginSuffix(), see below.
  virtual const nsCString Origin() const = 0;

  // The origin attributes suffix alone, this is usually passed as an
  // |aOriginSuffix| argument to various methods
  virtual const nsCString& OriginSuffix() const = 0;

  // The origin in the database usage format (reversed) and without the suffix
  virtual const nsCString& OriginNoSuffix() const = 0;

  // Whether the cache is already fully loaded
  virtual bool Loaded() = 0;

  // How many items has so far been loaded into the cache, used
  // for optimization purposes
  virtual uint32_t LoadedCount() = 0;

  // Called by the database to load a key and its value to the cache
  virtual bool LoadItem(const nsAString& aKey, const nsAString& aValue) = 0;

  // Called by the database after all keys and values has been loaded
  // to this cache
  virtual void LoadDone(nsresult aRv) = 0;

  // Use to synchronously wait until the cache gets fully loaded with data,
  // this method exits after LoadDone has been called
  virtual void LoadWait() = 0;

protected:
  virtual ~LocalStorageCacheBridge() = default;

  ThreadSafeAutoRefCnt mRefCnt;
  NS_DECL_OWNINGTHREAD
};

// Implementation of scope cache that is responsible for preloading data
// for persistent storage (localStorage) and hold data for non-private,
// private and session-only cookie modes.  It is also responsible for
// persisting data changes using the database, works as a write-back cache.
class LocalStorageCache : public LocalStorageCacheBridge {
public:
  void AssertIsOnOwningThread() const { NS_ASSERT_OWNINGTHREAD(LocalStorage); }

  void SetActor(LocalStorageCacheChild* aActor);

  void ClearActor() {
    AssertIsOnOwningThread();

    mActor = nullptr;
  }

  NS_IMETHOD_(void) Release(void) override;

  enum MutationSource {
    // The mutation is a result of an explicit JS mutation in this process.
    // The mutation should be sent to the sDatabase. Quota will be checked and
    // QuotaExceededError may be returned without the mutation being applied.
    ContentMutation,
    // The mutation initially was triggered in a different process and is being
    // propagated to this cache via LocalStorage::ApplyEvent.  The mutation
    // should
    // not be sent to the sDatabase because the originating process is already
    // doing that.  (In addition to the redundant writes being wasteful, there
    // is the potential for other processes to see inconsistent state from the
    // database while preloading.)  Quota will be updated but not checked
    // because it's assumed it was checked in another process and data-coherency
    // is more important than slightly exceeding quota.
    E10sPropagated
  };

  // Note: We pass aOriginNoSuffix through the ctor here, because
  // LocalStorageCacheHashKey's ctor is creating this class and
  // accepts reversed-origin-no-suffix as an argument - the hashing key.
  explicit LocalStorageCache(const nsACString* aOriginNoSuffix);

protected:
  virtual ~LocalStorageCache();

public:
  void Init(LocalStorageManager* aManager, bool aPersistent,
            nsIPrincipal* aPrincipal, const nsACString& aQuotaOriginScope);

  // Get size of per-origin data.
  int64_t GetOriginQuotaUsage(const LocalStorage* aStorage) const;

  // Starts async preload of this cache if it persistent and not loaded.
  void Preload();

  // The set of methods that are invoked by DOM storage web API.
  // We are passing the LocalStorage object just to let the cache
  // read properties like mPrivate and mSessionOnly.
  // Get* methods return error when load from the database has failed.
  nsresult GetLength(const LocalStorage* aStorage, uint32_t* aRetval);
  nsresult GetKey(const LocalStorage* aStorage, uint32_t index,
                  nsAString& aRetval);
  nsresult GetItem(const LocalStorage* aStorage, const nsAString& aKey,
                   nsAString& aRetval);
  nsresult SetItem(const LocalStorage* aStorage, const nsAString& aKey,
                   const nsAString& aValue, nsString& aOld,
                   const MutationSource aSource = ContentMutation);
  nsresult RemoveItem(const LocalStorage* aStorage, const nsAString& aKey,
                      nsString& aOld,
                      const MutationSource aSource = ContentMutation);
  nsresult Clear(const LocalStorage* aStorage,
                 const MutationSource aSource = ContentMutation);

  void GetKeys(const LocalStorage* aStorage, nsTArray<nsString>& aKeys);

  // LocalStorageCacheBridge

  const nsCString Origin() const override;
  const nsCString& OriginNoSuffix() const override { return mOriginNoSuffix; }
  const nsCString& OriginSuffix() const override { return mOriginSuffix; }
  bool Loaded() override { return mLoaded; }
  uint32_t LoadedCount() override;
  bool LoadItem(const nsAString& aKey, const nsAString& aValue) override;
  void LoadDone(nsresult aRv) override;
  void LoadWait() override;

  // Cache keeps 3 sets of data: regular, private and session-only.
  // This class keeps keys and values for a set and also caches
  // size of the data for quick per-origin quota checking.
  class Data {
   public:
    Data() : mOriginQuotaUsage(0) {}
    int64_t mOriginQuotaUsage;
    nsTHashMap<nsStringHashKey, nsString> mKeys;
  };

public:
  // Number of data sets we keep: default, session
  static const uint32_t kDataSetCount = 2;

private:
  // API to clear the cache data, this is invoked by chrome operations
  // like cookie deletion.
  friend class LocalStorageManager;

  static const uint32_t kUnloadDefault = 1 << 0;
  static const uint32_t kUnloadSession = 1 << 1;
  static const uint32_t kUnloadComplete = kUnloadDefault | kUnloadSession;

#ifdef DOM_STORAGE_TESTS
  static const uint32_t kTestReload = 1 << 15;
#endif

  void UnloadItems(uint32_t aUnloadFlags);

private:
  // Synchronously blocks until the cache is fully loaded from the database
  void WaitForPreload();

  // Helper to get one of the 3 data sets (regular, private, session)
  Data& DataSet(const LocalStorage* aStorage);

  // Used for firing storage events and synchronization of caches in other
  // content processes.
  void NotifyObservers(const LocalStorage* aStorage, const nsAString& aKey,
                       const nsAString& aOldValue, const nsAString& aNewValue);

  // Whether the storage change is about to persist
  bool Persist(const LocalStorage* aStorage) const;

  // Changes the quota usage on the given data set if it fits the quota.
  // If not, then false is returned and no change to the set must be done.
  // A special case is if aSource==E10sPropagated, then we will return true even
  // if the change would put us over quota.  This is done to ensure coherency of
  // caches between processes in the face of races.  It does allow an attacker
  // to potentially use N multiples of the quota storage limit if they can
  // arrange for their origin to execute code in N processes.  However, this is
  // not considered a particularly concerning threat model because it's already
  // very possible for a rogue page to attempt to intentionally fill up the
  // user's storage through the use of multiple domains.
  bool ProcessUsageDelta(uint32_t aGetDataSetIndex, const int64_t aDelta,
                         const MutationSource aSource = ContentMutation);
  bool ProcessUsageDelta(const LocalStorage* aStorage, const int64_t aDelta,
                         const MutationSource aSource = ContentMutation);

private:
  // When a cache is reponsible for its life time (in case of localStorage data
  // cache) we need to refer our manager since removal of the cache from the
  // hash table is handled in the destructor by call to the manager.  Cache
  // could potentially overlive the manager, hence the hard ref.
  RefPtr<LocalStorageManager> mManager;

  // Reference to the usage counter object we check on for eTLD+1 quota limit.
  // Obtained from the manager during initialization (Init method).
  RefPtr<StorageUsage> mUsage;

  // The LocalStorageCacheChild is created at the same time of this class.
  // In normal operation, the actor will be synchronously cleared in our
  // destructor when we tell it to delete itself.  In a shutdown-related edge
  // case in the parent process for JSM's, it is possible for the actor to be
  // destroyed while this class remains alive, in which case it will be nulled
  // out.
  LocalStorageCacheChild* mActor;

  // The origin this cache belongs to in the "DB format", i.e. reversed
  nsCString mOriginNoSuffix;

  // The origin attributes suffix
  nsCString mOriginSuffix;

  // The eTLD+1 scope used to count quota usage.  It is in the reversed format
  // and contains the origin attributes suffix.
  nsCString mQuotaOriginScope;

  // Non-private Browsing, Private Browsing and Session Only sets.
  Data mData[kDataSetCount];

  // This monitor is used to wait for full load of data.
  mozilla::Monitor mMonitor MOZ_UNANNOTATED;

  // Flag that is initially false.  When the cache is about to work with
  // the database (i.e. it is persistent) this flags is set to true after
  // all keys and coresponding values are loaded from the database.
  // This flag never goes from true back to false.  Since this flag is
  // critical for mData hashtable synchronization, it's made atomic.
  Atomic<bool, ReleaseAcquire> mLoaded;

  // Result of load from the database.  Valid after mLoaded flag has been set.
  nsresult mLoadResult;

  // Expected to be only 0 or 1.
  uint32_t mPrivateBrowsingId;

  // Init() method has been called
  bool mInitialized : 1;

  // This cache is about to be bound with the database (i.e. it has
  // to load from the DB first and has to persist when modifying the
  // default data set.)
  bool mPersistent : 1;

  // Whether we have already captured state of the cache preload on our first
  // access.
  bool mPreloadTelemetryRecorded : 1;
};

// StorageUsage
// Infrastructure to manage and check eTLD+1 quota
class StorageUsageBridge {
public:
  NS_INLINE_DECL_THREADSAFE_VIRTUAL_REFCOUNTING(StorageUsageBridge)

  virtual const nsCString& OriginScope() = 0;
  virtual void LoadUsage(const int64_t aUsage) = 0;

protected:
  // Protected destructor, to discourage deletion outside of Release():
  virtual ~StorageUsageBridge() = default;
};

class StorageUsage : public StorageUsageBridge {
public:
  explicit StorageUsage(const nsACString& aOriginScope);

  bool CheckAndSetETLD1UsageDelta(
      uint32_t aDataSetIndex, int64_t aUsageDelta,
      const LocalStorageCache::MutationSource aSource);

private:
  const nsCString& OriginScope() override { return mOriginScope; }
  void LoadUsage(const int64_t aUsage) override;

  nsCString mOriginScope;
  int64_t mUsage[LocalStorageCache::kDataSetCount];
};

}  // namespace mozilla::dom

#endif  // mozilla_dom_LocalStorageCache_h

quality100%

¤ Dauer der Verarbeitung: 0.16 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.