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-rw-r--r--dom/localstorage/LSWriteOptimizerImpl.h62
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diff --git a/dom/localstorage/LSWriteOptimizerImpl.h b/dom/localstorage/LSWriteOptimizerImpl.h
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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_LSWriteOptimizerImpl_h
+#define mozilla_dom_localstorage_LSWriteOptimizerImpl_h
+
+#include "LSWriteOptimizer.h"
+
+namespace mozilla::dom {
+
+template <typename T, typename U>
+void LSWriteOptimizer<T, U>::InsertItem(const nsAString& aKey, const T& aValue,
+ int64_t aDelta) {
+ AssertIsOnOwningThread();
+
+ mWriteInfos.WithEntryHandle(aKey, [&](auto&& entry) {
+ if (entry && entry.Data()->GetType() == WriteInfo::DeleteItem) {
+ // We could just simply replace the deletion with ordinary update, but
+ // that would preserve item's original position/index. Imagine a case when
+ // we have only one existing key k1. Now let's create a new optimizer and
+ // remove k1, add k2 and add k1 back. The final order should be k2, k1
+ // (ordinary update would produce k1, k2). So we need to differentiate
+ // between normal update and "optimized" update which resulted from a
+ // deletion followed by an insertion. We use the UpdateWithMove flag for
+ // this.
+
+ entry.Update(MakeUnique<UpdateItemInfo>(NextSerialNumber(), aKey, aValue,
+ /* aUpdateWithMove */ true));
+ } else {
+ entry.InsertOrUpdate(
+ MakeUnique<InsertItemInfo>(NextSerialNumber(), aKey, aValue));
+ }
+ });
+
+ mTotalDelta += aDelta;
+}
+
+template <typename T, typename U>
+void LSWriteOptimizer<T, U>::UpdateItem(const nsAString& aKey, const T& aValue,
+ int64_t aDelta) {
+ AssertIsOnOwningThread();
+
+ mWriteInfos.WithEntryHandle(aKey, [&](auto&& entry) {
+ if (entry && entry.Data()->GetType() == WriteInfo::InsertItem) {
+ entry.Update(
+ MakeUnique<InsertItemInfo>(NextSerialNumber(), aKey, aValue));
+ } else {
+ entry.InsertOrUpdate(
+ MakeUnique<UpdateItemInfo>(NextSerialNumber(), aKey, aValue,
+ /* aUpdateWithMove */ false));
+ }
+ });
+
+ mTotalDelta += aDelta;
+}
+
+} // namespace mozilla::dom
+
+#endif // mozilla_dom_localstorage_LSWriteOptimizerImpl_h