src/paimon/core/stats/simple_stats_evolutions.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#pragma once

#include <memory>

#include "paimon/common/utils/concurrent_hash_map.h"
#include "paimon/core/schema/table_schema.h"
#include "paimon/core/stats/simple_stats_evolution.h"

namespace paimon {
class SimpleStatsEvolutions {
 public:
    SimpleStatsEvolutions(const std::shared_ptr<TableSchema>& table_schema,
                          const std::shared_ptr<MemoryPool>& pool)
        : pool_(pool), table_schema_(table_schema) {}

    std::shared_ptr<SimpleStatsEvolution> GetOrCreate(
        const std::shared_ptr<TableSchema>& data_schema) {
        auto data_schema_id = data_schema->Id();
        auto cached_evolution = evolutions_.Find(data_schema_id);
        if (cached_evolution != std::nullopt) {
            return cached_evolution.value();
        }
        bool need_mapping = data_schema_id != table_schema_->Id();
        auto evolution = std::make_shared<SimpleStatsEvolution>(
            data_schema->Fields(), table_schema_->Fields(), need_mapping, pool_);
        evolutions_.Insert(data_schema_id, evolution);
        return evolution;
    }

 private:
    std::shared_ptr<MemoryPool> pool_;
    std::shared_ptr<TableSchema> table_schema_;
    // scheme_id -> evolution
    ConcurrentHashMap<int64_t, std::shared_ptr<SimpleStatsEvolution>> evolutions_;
};
}  // namespace paimon