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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 http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LSSnapshot_h
+#define mozilla_dom_localstorage_LSSnapshot_h
+
+#include <cstdint>
+#include <cstdlib>
+#include "ErrorList.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "nsCOMPtr.h"
+#include "nsTHashMap.h"
+#include "nsHashKeys.h"
+#include "nsIRunnable.h"
+#include "nsISupports.h"
+#include "nsStringFwd.h"
+#include "nsTArrayForwardDeclare.h"
+#include "nsTHashSet.h"
+
+class nsITimer;
+
+namespace mozilla::dom {
+
+class LSDatabase;
+class LSNotifyInfo;
+class LSSnapshotChild;
+class LSSnapshotInitInfo;
+class LSWriteAndNotifyInfo;
+class SnapshotWriteOptimizer;
+
+template <typename>
+class Optional;
+
+class LSSnapshot final : public nsIRunnable {
+ public:
+ /**
+ * The LoadState expresses what subset of information a snapshot has from the
+ * authoritative Datastore in the parent process. The initial snapshot is
+ * populated heuristically based on the size of the keys and size of the items
+ * (inclusive of the key value; item is key+value, not just value) of the
+ * entire datastore relative to the configured prefill limit (via pref
+ * "dom.storage.snapshot_prefill" exposed as gSnapshotPrefill in bytes).
+ *
+ * If there's less data than the limit, we send both keys and values and end
+ * up as AllOrderedItems. If there's enough room for all the keys but not
+ * all the values, we end up as AllOrderedKeys with as many values present as
+ * would fit. If there's not enough room for all the keys, then we end up as
+ * Partial with as many key-value pairs as will fit.
+ *
+ * The state AllUnorderedItems can only be reached by code getting items one
+ * by one.
+ */
+ enum class LoadState {
+ /**
+ * Class constructed, Init(LSSnapshotInitInfo) has not been invoked yet.
+ */
+ Initial,
+ /**
+ * Some keys and their values are known.
+ */
+ Partial,
+ /**
+ * All the keys are known in order, but some values are unknown.
+ */
+ AllOrderedKeys,
+ /**
+ * All keys and their values are known, but in an arbitrary order.
+ */
+ AllUnorderedItems,
+ /**
+ * All keys and their values are known and are present in their canonical
+ * order. This is everything, and is the preferred case. The initial
+ * population will send this info when the size of all items is less than
+ * the prefill threshold.
+ *
+ * mValues will contain all keys and values, mLoadedItems and mUnknownItems
+ * are unused.
+ */
+ AllOrderedItems,
+ EndGuard
+ };
+
+ private:
+ RefPtr<LSSnapshot> mSelfRef;
+
+ RefPtr<LSDatabase> mDatabase;
+
+ nsCOMPtr<nsITimer> mIdleTimer;
+
+ LSSnapshotChild* mActor;
+
+ nsTHashSet<nsString> mLoadedItems;
+ nsTHashSet<nsString> mUnknownItems;
+ nsTHashMap<nsStringHashKey, nsString> mValues;
+ UniquePtr<SnapshotWriteOptimizer> mWriteOptimizer;
+ UniquePtr<nsTArray<LSWriteAndNotifyInfo>> mWriteAndNotifyInfos;
+
+ uint32_t mInitLength;
+ uint32_t mLength;
+ int64_t mUsage;
+ int64_t mPeakUsage;
+
+ LoadState mLoadState;
+
+ bool mHasOtherProcessDatabases;
+ bool mHasOtherProcessObservers;
+ bool mExplicit;
+ bool mHasPendingStableStateCallback;
+ bool mHasPendingIdleTimerCallback;
+ bool mDirty;
+
+#ifdef DEBUG
+ bool mInitialized;
+ bool mSentFinish;
+#endif
+
+ public:
+ explicit LSSnapshot(LSDatabase* aDatabase);
+
+ void AssertIsOnOwningThread() const { NS_ASSERT_OWNINGTHREAD(LSSnapshot); }
+
+ void SetActor(LSSnapshotChild* aActor);
+
+ void ClearActor() {
+ AssertIsOnOwningThread();
+ MOZ_ASSERT(mActor);
+
+ mActor = nullptr;
+ }
+
+ bool Explicit() const { return mExplicit; }
+
+ nsresult Init(const nsAString& aKey, const LSSnapshotInitInfo& aInitInfo,
+ bool aExplicit);
+
+ nsresult GetLength(uint32_t* aResult);
+
+ nsresult GetKey(uint32_t aIndex, nsAString& aResult);
+
+ nsresult GetItem(const nsAString& aKey, nsAString& aResult);
+
+ nsresult GetKeys(nsTArray<nsString>& aKeys);
+
+ nsresult SetItem(const nsAString& aKey, const nsAString& aValue,
+ LSNotifyInfo& aNotifyInfo);
+
+ nsresult RemoveItem(const nsAString& aKey, LSNotifyInfo& aNotifyInfo);
+
+ nsresult Clear(LSNotifyInfo& aNotifyInfo);
+
+ void MarkDirty();
+
+ nsresult ExplicitCheckpoint();
+
+ nsresult ExplicitEnd();
+
+ int64_t GetUsage() const;
+
+ private:
+ ~LSSnapshot();
+
+ void ScheduleStableStateCallback();
+
+ void MaybeScheduleStableStateCallback();
+
+ nsresult GetItemInternal(const nsAString& aKey,
+ const Optional<nsString>& aValue,
+ nsAString& aResult);
+
+ nsresult EnsureAllKeys();
+
+ nsresult UpdateUsage(int64_t aDelta);
+
+ nsresult Checkpoint(bool aSync = false);
+
+ nsresult Finish(bool aSync = false);
+
+ void CancelIdleTimer();
+
+ static void IdleTimerCallback(nsITimer* aTimer, void* aClosure);
+
+ NS_DECL_ISUPPORTS
+ NS_DECL_NSIRUNNABLE
+};
+
+} // namespace mozilla::dom
+
+#endif // mozilla_dom_localstorage_LSSnapshot_h