1 files changed, 191 insertions, 0 deletions
diff --git a/dom/storage/SessionStorageManager.h b/dom/storage/SessionStorageManager.h
new file mode 100644
index 0000000000..fed41bb4db
--- /dev/null
+++ b/dom/storage/SessionStorageManager.h
@@ -0,0 +1,191 @@
+/* -*- 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_SessionStorageManager_h
+#define mozilla_dom_SessionStorageManager_h
+
+#include "StorageObserver.h"
+
+#include "mozilla/dom/FlippedOnce.h"
+#include "nsIDOMStorageManager.h"
+#include "nsClassHashtable.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsHashKeys.h"
+
+namespace mozilla {
+class OriginAttributesPattern;
+
+namespace dom {
+
+bool RecvShutdownBackgroundSessionStorageManagers();
+void RecvPropagateBackgroundSessionStorageManager(uint64_t aCurrentTopContextId,
+                                                  uint64_t aTargetTopContextId);
+bool RecvRemoveBackgroundSessionStorageManager(uint64_t aTopContextId);
+
+class BrowsingContext;
+class ContentParent;
+class SSSetItemInfo;
+class SSWriteInfo;
+class SessionStorageCache;
+class SessionStorageCacheChild;
+class SessionStorageManagerChild;
+class SessionStorageManagerParent;
+class SessionStorageObserver;
+struct OriginRecord;
+
+// sessionStorage is a data store that's unique to each tab (i.e. top-level
+// browsing context) and origin. Before the advent of Fission all the data
+// for a given tab could be stored in a single content process; now each
+// site-specific process stores only its portion of the data. As content
+// processes terminate, their sessionStorage data needs to be saved in the
+// parent process, in case the same origin appears again in the tab (e.g.
+// by navigating an iframe element). Therefore SessionStorageManager
+// objects exist in both the parent and content processes.
+//
+// Whenever a write operation for SessionStorage executes, the content process
+// sends the changes to the parent process at the next stable state. Whenever a
+// content process navigates to an origin for the first time in a given tab, the
+// parent process sends it the saved data. SessionStorageCache has a flag
+// (mLoadedOrCloned) to ensure that it's only be loaded or cloned once.
+//
+// Note: the current implementation is expected to be replaced by a new
+// implementation using LSNG.
+class SessionStorageManagerBase {
+ public:
+  SessionStorageManagerBase() = default;
+
+ protected:
+  ~SessionStorageManagerBase() = default;
+
+  struct OriginRecord {
+    OriginRecord() = default;
+    OriginRecord(OriginRecord&&) = default;
+    OriginRecord& operator=(OriginRecord&&) = default;
+    ~OriginRecord();
+
+    RefPtr<SessionStorageCache> mCache;
+
+    // A flag to ensure that cache is only loaded once.
+    FlippedOnce<false> mLoaded;
+  };
+
+  OriginRecord* GetOriginRecord(const nsACString& aOriginAttrs,
+                                const nsACString& aOriginKey,
+                                bool aMakeIfNeeded,
+                                SessionStorageCache* aCloneFrom);
+
+  using OriginKeyHashTable = nsClassHashtable<nsCStringHashKey, OriginRecord>;
+  nsClassHashtable<nsCStringHashKey, OriginKeyHashTable> mOATable;
+};
+
+class SessionStorageManager final : public SessionStorageManagerBase,
+                                    public nsIDOMSessionStorageManager,
+                                    public StorageObserverSink {
+ public:
+  explicit SessionStorageManager(RefPtr<BrowsingContext> aBrowsingContext);
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_NSIDOMSTORAGEMANAGER
+  NS_DECL_NSIDOMSESSIONSTORAGEMANAGER
+
+  NS_DECL_CYCLE_COLLECTION_CLASS(SessionStorageManager)
+
+  bool CanLoadData();
+
+  void SetActor(SessionStorageManagerChild* aActor);
+
+  bool ActorExists() const;
+
+  void ClearActor();
+
+  nsresult EnsureManager();
+
+  nsresult LoadData(nsIPrincipal& aPrincipal, SessionStorageCache& aCache);
+
+  void CheckpointData(nsIPrincipal& aPrincipal, SessionStorageCache& aCache);
+
+ private:
+  ~SessionStorageManager();
+
+  // StorageObserverSink, handler to various chrome clearing notification
+  nsresult Observe(const char* aTopic,
+                   const nsAString& aOriginAttributesPattern,
+                   const nsACString& aOriginScope) override;
+
+  nsresult GetSessionStorageCacheHelper(nsIPrincipal* aPrincipal,
+                                        bool aMakeIfNeeded,
+                                        SessionStorageCache* aCloneFrom,
+                                        RefPtr<SessionStorageCache>* aRetVal);
+
+  nsresult GetSessionStorageCacheHelper(const nsACString& aOriginAttrs,
+                                        const nsACString& aOriginKey,
+                                        bool aMakeIfNeeded,
+                                        SessionStorageCache* aCloneFrom,
+                                        RefPtr<SessionStorageCache>* aRetVal);
+
+  enum ClearStorageType {
+    eAll,
+    eSessionOnly,
+  };
+  void ClearStorages(ClearStorageType aType,
+                     const OriginAttributesPattern& aPattern,
+                     const nsACString& aOriginScope);
+
+  SessionStorageCacheChild* EnsureCache(const nsCString& aOriginAttrs,
+                                        const nsCString& aOriginKey,
+                                        SessionStorageCache& aCache);
+
+  void CheckpointDataInternal(const nsCString& aOriginAttrs,
+                              const nsCString& aOriginKey,
+                              SessionStorageCache& aCache);
+
+  RefPtr<SessionStorageObserver> mObserver;
+
+  RefPtr<BrowsingContext> mBrowsingContext;
+
+  SessionStorageManagerChild* mActor;
+};
+
+/**
+ * A specialized SessionStorageManager class that lives on the parent process
+ * background thread. It is a shadow copy of SessionStorageManager and it's used
+ * to preserve SessionStorageCaches for the other SessionStorageManagers.
+ */
+class BackgroundSessionStorageManager final : public SessionStorageManagerBase {
+ public:
+  // Parent process getter function.
+  static BackgroundSessionStorageManager* GetOrCreate(uint64_t aTopContextId);
+
+  NS_INLINE_DECL_REFCOUNTING(BackgroundSessionStorageManager);
+
+  // Only called by CanonicalBrowsingContext::ReplaceBy on the parent process.
+  static void PropagateManager(uint64_t aCurrentTopContextId,
+                               uint64_t aTargetTopContextId);
+
+  // Only called by CanonicalBrowsingContext::CanonicalDiscard on parent
+  // process.
+  static void RemoveManager(uint64_t aTopContextId);
+
+  void CopyDataToContentProcess(const nsACString& aOriginAttrs,
+                                const nsACString& aOriginKey,
+                                nsTArray<SSSetItemInfo>& aDefaultData,
+                                nsTArray<SSSetItemInfo>& aSessionData);
+
+  void UpdateData(const nsACString& aOriginAttrs, const nsACString& aOriginKey,
+                  const nsTArray<SSWriteInfo>& aDefaultWriteInfos,
+                  const nsTArray<SSWriteInfo>& aSessionWriteInfos);
+
+ private:
+  // Only be called by GetOrCreate() on the parent process.
+  explicit BackgroundSessionStorageManager();
+
+  ~BackgroundSessionStorageManager();
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_SessionStorageManager_h