diff -r 000000000000 -r 6474c204b198 dom/src/storage/DOMStorageCache.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/src/storage/DOMStorageCache.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,273 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 nsDOMStorageCache_h___
+#define nsDOMStorageCache_h___
+
+#include "nsIURI.h"
+#include "nsIPrincipal.h"
+#include "nsITimer.h"
+
+#include "nsString.h"
+#include "nsDataHashtable.h"
+#include "nsHashKeys.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/Telemetry.h"
+#include "nsAutoPtr.h"
+
+namespace mozilla {
+namespace dom {
+
+class DOMStorage;
+class DOMStorageUsage;
+class DOMStorageManager;
+class DOMStorageDBBridge;
+
+// Interface class on which only the database or IPC may call.
+// Used to populate the cache with DB data.
+class DOMStorageCacheBridge
+{
+public:
+  NS_IMETHOD_(MozExternalRefCountType) AddRef(void);
+  NS_IMETHOD_(void) Release(void);
+
+  virtual ~DOMStorageCacheBridge() {}
+
+  // The scope (origin) in the database usage format (reversed)
+  virtual const nsCString& Scope() 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;
+
+protected:
+  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 DOMStorageCache : public DOMStorageCacheBridge
+{
+public:
+  NS_IMETHOD_(void) Release(void);
+
+  DOMStorageCache(const nsACString* aScope);
+  virtual ~DOMStorageCache();
+
+  void Init(DOMStorageManager* aManager, bool aPersistent,
+            nsIURI* aFirstPartyIsolationURI, nsIPrincipal* aPrincipal,
+            const nsACString& aQuotaScope);
+
+  // Copies all data from the other storage.
+  void CloneFrom(const DOMStorageCache* aThat);
+
+  // Starts async preload of this cache if it persistent and not loaded.
+  void Preload();
+
+  // Keeps the cache alive (i.e. present in the manager's hash table) for a time.
+  void KeepAlive();
+
+  // The set of methods that are invoked by DOM storage web API.
+  // We are passing the DOMStorage 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 DOMStorage* aStorage, uint32_t* aRetval);
+  nsresult GetKey(const DOMStorage* aStorage, uint32_t index, nsAString& aRetval);
+  nsresult GetItem(const DOMStorage* aStorage, const nsAString& aKey, nsAString& aRetval);
+  nsresult SetItem(const DOMStorage* aStorage, const nsAString& aKey, const nsString& aValue, nsString& aOld);
+  nsresult RemoveItem(const DOMStorage* aStorage, const nsAString& aKey, nsString& aOld);
+  nsresult Clear(const DOMStorage* aStorage);
+
+  nsTArray<nsString>* GetKeys(const DOMStorage* aStorage);
+
+  nsIURI* FirstPartyIsolationURI() const { return mFirstPartyIsolationURI; }
+
+  // Whether the principal equals principal the cache was created for
+  bool CheckPrincipal(nsIPrincipal* aPrincipal) const;
+  nsIPrincipal* Principal() const { return mPrincipal; }
+
+  // Starts the database engine thread or the IPC bridge
+  static DOMStorageDBBridge* StartDatabase();
+  static DOMStorageDBBridge* GetDatabase();
+
+  // Stops the thread and flushes all uncommited data
+  static nsresult StopDatabase();
+
+  // DOMStorageCacheBridge
+
+  virtual const nsCString& Scope() const { return mScope; }
+  virtual bool Loaded() { return mLoaded; }
+  virtual uint32_t LoadedCount();
+  virtual bool LoadItem(const nsAString& aKey, const nsString& aValue);
+  virtual void LoadDone(nsresult aRv);
+  virtual void LoadWait();
+
+  // 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;
+    nsDataHashtable<nsStringHashKey, nsString> mKeys;
+  };
+
+public:
+  // Number of data sets we keep: default, private, session
+  static const uint32_t kDataSetCount = 3;
+
+private:
+  // API to clear the cache data, this is invoked by chrome operations
+  // like cookie deletion.
+  friend class DOMStorageManager;
+
+  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;
+
+#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(mozilla::Telemetry::ID aTelemetryID);
+
+  // Helper to get one of the 3 data sets (regular, private, session)
+  Data& DataSet(const DOMStorage* aStorage);
+
+  // Whether the storage change is about to persist
+  bool Persist(const DOMStorage* 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.
+  bool ProcessUsageDelta(uint32_t aGetDataSetIndex, const int64_t aDelta);
+  bool ProcessUsageDelta(const DOMStorage* aStorage, const int64_t aDelta);
+
+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.
+  nsRefPtr<DOMStorageManager> mManager;
+
+  // Reference to the usage counter object we check on for eTLD+1 quota limit.
+  // Obtained from the manager during initialization (Init method).
+  nsRefPtr<DOMStorageUsage> mUsage;
+
+  // Timer that holds this cache alive for a while after it has been preloaded.
+  nsCOMPtr<nsITimer> mKeepAliveTimer;
+
+  // The first party URI associated with this cache.
+  nsCOMPtr<nsIURI> mFirstPartyIsolationURI;
+
+  // Principal the cache has been initially created for, this is used only
+  // for sessionStorage access checks since sessionStorage objects are strictly
+  // scoped by a principal.  localStorage objects on the other hand are scoped by
+  // origin only.
+  nsCOMPtr<nsIPrincipal> mPrincipal;
+
+  // The scope this cache belongs to in the "DB format", i.e. reversed
+  nsCString mScope;
+
+  // The eTLD+1 scope used to count quota usage.
+  nsCString mQuotaScope;
+
+  // 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.
+  bool 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;
+
+  // - False when the session-only data set was never used.
+  // - True after access to session-only data has been made for the first time.
+  // We also fill session-only data set with the default one at that moment.
+  // Drops back to false when session-only data are cleared from chrome.
+  bool mSessionOnlyDataSetActive : 1;
+
+  // Whether we have already captured state of the cache preload on our first access.
+  bool mPreloadTelemetryRecorded : 1;
+
+  // DOMStorageDBThread on the parent or single process,
+  // DOMStorageDBChild on the child process.
+  static DOMStorageDBBridge* sDatabase;
+
+  // False until we shut the database down.
+  static bool sDatabaseDown;
+};
+
+// DOMStorageUsage
+// Infrastructure to manage and check eTLD+1 quota
+class DOMStorageUsageBridge
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(DOMStorageUsageBridge)
+
+  virtual const nsCString& Scope() = 0;
+  virtual void LoadUsage(const int64_t aUsage) = 0;
+
+protected:
+  // Protected destructor, to discourage deletion outside of Release():
+  virtual ~DOMStorageUsageBridge() {}
+};
+
+class DOMStorageUsage : public DOMStorageUsageBridge
+{
+public:
+  DOMStorageUsage(const nsACString& aScope);
+
+  bool CheckAndSetETLD1UsageDelta(uint32_t aDataSetIndex, int64_t aUsageDelta);
+
+private:
+  virtual const nsCString& Scope() { return mScope; }
+  virtual void LoadUsage(const int64_t aUsage);
+
+  nsCString mScope;
+  int64_t mUsage[DOMStorageCache::kDataSetCount];
+};
+
+} // ::dom
+} // ::mozilla
+
+#endif