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/* -*- 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 */
#ifndef mozilla_dom_LocalStorageCache_h
#define mozilla_dom_LocalStorageCache_h
#include "nsIPrincipal.h"
#include "nsString.h"
#include "nsDataHashtable.h"
#include "nsHashKeys.h"
#include "mozilla/Monitor.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Atomics.h"
namespace mozilla {
namespace 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 {
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 nsString& 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;
virtual ~LocalStorageCacheBridge() = default;
ThreadSafeAutoRefCnt mRefCnt;
// 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 {
void AssertIsOnOwningThread() const { NS_ASSERT_OWNINGTHREAD(LocalStorage); }
void SetActor(LocalStorageCacheChild* aActor);
void ClearActor() {
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.
// 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.
// 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);
virtual ~LocalStorageCache();
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 nsString& 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 nsString& 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 {
Data() : mOriginQuotaUsage(0) {}
int64_t mOriginQuotaUsage;
nsDataHashtable<nsStringHashKey, nsString> mKeys;
// Number of data sets we keep: default, private, session
static const uint32_t kDataSetCount = 3;
// 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 kUnloadPrivate = 1 << 1;
static const uint32_t kUnloadSession = 1 << 2;
static const uint32_t kUnloadComplete =
kUnloadDefault | kUnloadPrivate | kUnloadSession;
static const uint32_t kTestReload = 1 << 15;
void UnloadItems(uint32_t aUnloadFlags);
// Synchronously blocks until the cache is fully loaded from the database
void WaitForPreload(mozilla::Telemetry::HistogramID aTelemetryID);
// 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 nsString& aKey,
const nsString& aOldValue, const nsString& 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);
// 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;
// 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;
// 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 {
virtual const nsCString& OriginScope() = 0;
virtual void LoadUsage(const int64_t aUsage) = 0;
// Protected destructor, to discourage deletion outside of Release():
virtual ~StorageUsageBridge() = default;
class StorageUsage : public StorageUsageBridge {
explicit StorageUsage(const nsACString& aOriginScope);
bool CheckAndSetETLD1UsageDelta(
uint32_t aDataSetIndex, int64_t aUsageDelta,
const LocalStorageCache::MutationSource aSource);
const nsCString& OriginScope() override { return mOriginScope; }
void LoadUsage(const int64_t aUsage) override;
nsCString mOriginScope;
int64_t mUsage[LocalStorageCache::kDataSetCount];
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_LocalStorageCache_h