gecko-dev/dom/localstorage/LSWriteOptimizer.cpp

117 строки
3.7 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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/. */
#include "LSWriteOptimizer.h"
namespace mozilla {
namespace dom {
class LSWriteOptimizerBase::WriteInfoComparator {
public:
bool Equals(const WriteInfo* a, const WriteInfo* b) const {
MOZ_ASSERT(a && b);
return a->SerialNumber() == b->SerialNumber();
}
bool LessThan(const WriteInfo* a, const WriteInfo* b) const {
MOZ_ASSERT(a && b);
return a->SerialNumber() < b->SerialNumber();
}
};
void LSWriteOptimizerBase::DeleteItem(const nsAString& aKey, int64_t aDelta) {
AssertIsOnOwningThread();
WriteInfo* existingWriteInfo;
if (mWriteInfos.Get(aKey, &existingWriteInfo) &&
existingWriteInfo->GetType() == WriteInfo::InsertItem) {
mWriteInfos.Remove(aKey);
} else {
nsAutoPtr<WriteInfo> newWriteInfo(
new DeleteItemInfo(NextSerialNumber(), aKey));
mWriteInfos.Put(aKey, newWriteInfo.forget());
}
mTotalDelta += aDelta;
}
void LSWriteOptimizerBase::Truncate(int64_t aDelta) {
AssertIsOnOwningThread();
mWriteInfos.Clear();
if (!mTruncateInfo) {
mTruncateInfo = new TruncateInfo(NextSerialNumber());
}
mTotalDelta += aDelta;
}
void LSWriteOptimizerBase::GetSortedWriteInfos(
nsTArray<WriteInfo*>& aWriteInfos) {
AssertIsOnOwningThread();
if (mTruncateInfo) {
aWriteInfos.InsertElementSorted(mTruncateInfo, WriteInfoComparator());
}
for (auto iter = mWriteInfos.ConstIter(); !iter.Done(); iter.Next()) {
WriteInfo* writeInfo = iter.UserData();
aWriteInfos.InsertElementSorted(writeInfo, WriteInfoComparator());
}
}
template <typename T, typename U>
void LSWriteOptimizer<T, U>::InsertItem(const nsAString& aKey, const T& aValue,
int64_t aDelta) {
AssertIsOnOwningThread();
WriteInfo* existingWriteInfo;
nsAutoPtr<WriteInfo> newWriteInfo;
if (mWriteInfos.Get(aKey, &existingWriteInfo) &&
existingWriteInfo->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.
newWriteInfo = new UpdateItemInfo(NextSerialNumber(), aKey, aValue,
/* aUpdateWithMove */ true);
} else {
newWriteInfo = new InsertItemInfo(NextSerialNumber(), aKey, aValue);
}
mWriteInfos.Put(aKey, newWriteInfo.forget());
mTotalDelta += aDelta;
}
template <typename T, typename U>
void LSWriteOptimizer<T, U>::UpdateItem(const nsAString& aKey, const T& aValue,
int64_t aDelta) {
AssertIsOnOwningThread();
WriteInfo* existingWriteInfo;
nsAutoPtr<WriteInfo> newWriteInfo;
if (mWriteInfos.Get(aKey, &existingWriteInfo) &&
existingWriteInfo->GetType() == WriteInfo::InsertItem) {
newWriteInfo = new InsertItemInfo(NextSerialNumber(), aKey, aValue);
} else {
newWriteInfo = new UpdateItemInfo(NextSerialNumber(), aKey, aValue,
/* aUpdateWithMove */ false);
}
mWriteInfos.Put(aKey, newWriteInfo.forget());
mTotalDelta += aDelta;
}
} // namespace dom
} // namespace mozilla