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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
#pragma once
#include <utils/smallstringview.h>
#include <optional>
#include <type_traits>
namespace Sqlite {
constexpr int compare(Utils::SmallStringView first, Utils::SmallStringView second) noexcept
{
return first.compare(second);
}
enum class UpdateChange { No, Update };
template<typename SqliteRange,
typename Range,
typename CompareKey,
typename InsertCallback,
typename UpdateCallback,
typename DeleteCallback>
void insertUpdateDelete(SqliteRange &&sqliteRange,
Range &&values,
CompareKey compareKey,
InsertCallback insertCallback,
UpdateCallback updateCallback,
DeleteCallback deleteCallback)
{
auto currentSqliteIterator = sqliteRange.begin();
auto endSqliteIterator = sqliteRange.end();
auto currentValueIterator = values.begin();
auto endValueIterator = values.end();
auto lastValueIterator = endValueIterator;
auto doUpdate = [&](const auto &sqliteValue, const auto &value) {
UpdateChange updateChange = updateCallback(sqliteValue, value);
switch (updateChange) {
case UpdateChange::Update:
lastValueIterator = currentValueIterator;
break;
case UpdateChange::No:
lastValueIterator = endValueIterator;
break;
}
++currentSqliteIterator;
++currentValueIterator;
};
auto doInsert = [&](const auto &value) {
insertCallback(value);
++currentValueIterator;
};
auto doDelete = [&](const auto &sqliteValue) {
if (lastValueIterator != endValueIterator) {
if (compareKey(sqliteValue, *lastValueIterator) != 0)
deleteCallback(sqliteValue);
lastValueIterator = endValueIterator;
} else {
deleteCallback(sqliteValue);
}
++currentSqliteIterator;
};
while (true) {
bool hasMoreValues = currentValueIterator != endValueIterator;
bool hasMoreSqliteValues = currentSqliteIterator != endSqliteIterator;
if (hasMoreValues && hasMoreSqliteValues) {
auto &&sqliteValue = *currentSqliteIterator;
auto &&value = *currentValueIterator;
auto compare = compareKey(sqliteValue, value);
if (compare == 0)
doUpdate(sqliteValue, value);
else if (compare > 0)
doInsert(value);
else if (compare < 0)
doDelete(sqliteValue);
} else if (hasMoreValues) {
doInsert(*currentValueIterator);
} else if (hasMoreSqliteValues) {
doDelete(*currentSqliteIterator);
} else {
break;
}
}
}
} // namespace Sqlite
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