dom/localstorage/LSWriteOptimizerImpl.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_localstorage_LSWriteOptimizerImpl_h
   8 #define mozilla_dom_localstorage_LSWriteOptimizerImpl_h
   9
  10 #include "LSWriteOptimizer.h"
  11
  12 namespace mozilla::dom {
  13
  14 template <typename T, typename U>
  15 void LSWriteOptimizer<T, U>::InsertItem(const nsAString& aKey, const T& aValue,
  16                                         int64_t aDelta) {
  17   AssertIsOnOwningThread();
  18
  19   mWriteInfos.WithEntryHandle(aKey, [&](auto&& entry) {
  20     if (entry && entry.Data()->GetType() == WriteInfo::DeleteItem) {
  21       // We could just simply replace the deletion with ordinary update, but
  22       // that would preserve item's original position/index. Imagine a case when
  23       // we have only one existing key k1. Now let's create a new optimizer and
  24       // remove k1, add k2 and add k1 back. The final order should be k2, k1
  25       // (ordinary update would produce k1, k2). So we need to differentiate
  26       // between normal update and "optimized" update which resulted from a
  27       // deletion followed by an insertion. We use the UpdateWithMove flag for
  28       // this.
  29
  30       entry.Update(MakeUnique<UpdateItemInfo>(NextSerialNumber(), aKey, aValue,
  31                                               /* aUpdateWithMove */ true));
  32     } else {
  33       entry.InsertOrUpdate(
  34           MakeUnique<InsertItemInfo>(NextSerialNumber(), aKey, aValue));
  35     }
  36   });
  37
  38   mTotalDelta += aDelta;
  39 }
  40
  41 template <typename T, typename U>
  42 void LSWriteOptimizer<T, U>::UpdateItem(const nsAString& aKey, const T& aValue,
  43                                         int64_t aDelta) {
  44   AssertIsOnOwningThread();
  45
  46   mWriteInfos.WithEntryHandle(aKey, [&](auto&& entry) {
  47     if (entry && entry.Data()->GetType() == WriteInfo::InsertItem) {
  48       entry.Update(
  49           MakeUnique<InsertItemInfo>(NextSerialNumber(), aKey, aValue));
  50     } else {
  51       entry.InsertOrUpdate(
  52           MakeUnique<UpdateItemInfo>(NextSerialNumber(), aKey, aValue,
  53                                      /* aUpdateWithMove */ false));
  54     }
  55   });
  56
  57   mTotalDelta += aDelta;
  58 }
  59
  60 }  // namespace mozilla::dom
  61
  62 #endif  // mozilla_dom_localstorage_LSWriteOptimizerImpl_h