gecko-dev/dom/localstorage/LSWriteOptimizerImpl.h

63 lines
2.4 KiB
C++

/* -*- 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