src/paimon/core/schema/schema_manager.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 <cstdint>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <vector>

#include "paimon/core/schema/table_schema.h"
#include "paimon/fs/file_system.h"
#include "paimon/result.h"

namespace arrow {
class Schema;
}  // namespace arrow

namespace paimon {
class FileSystem;

/// Schema Manager to manage schema versions.
class SchemaManager {
 public:
    SchemaManager(const std::shared_ptr<FileSystem>& file_system, const std::string& table_root);
    /// Specify the default branch for data writing.
    SchemaManager(const std::shared_ptr<FileSystem>& file_system, const std::string& table_root,
                  const std::string& branch);

    /// Read schema for schema id. Find schema in cache first.
    Result<std::shared_ptr<TableSchema>> ReadSchema(int64_t schema_id) const;
    Result<std::optional<std::shared_ptr<TableSchema>>> Latest() const;
    Result<std::unique_ptr<TableSchema>> CreateTable(
        const std::shared_ptr<arrow::Schema>& schema,
        const std::vector<std::string>& partition_keys,
        const std::vector<std::string>& primary_keys,
        const std::map<std::string, std::string>& options);

    std::string SchemaDirectory() const;
    Result<bool> SchemaExists(int64_t id) const;
    Result<std::vector<int64_t>> ListAllIds() const;

 private:
    std::string BranchPath() const;
    std::string ToSchemaPath(int64_t schema_id) const;

 private:
    static constexpr char SCHEMA_PREFIX[] = "schema-";

 private:
    std::shared_ptr<FileSystem> file_system_;
    std::string table_root_;
    const std::string branch_;
    mutable std::map<int64_t, std::shared_ptr<TableSchema>> schema_cache_;
};

}  // namespace paimon