src/paimon/common/data/shredding/shredding_read_plan.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/memory/memory_pool.h"
#include "paimon/result.h"

namespace arrow {
class Array;
class Field;
class MemoryPool;
}  // namespace arrow

namespace paimon {

/// A per-column read plan translating between a column's logical shape and the physical
/// (shredded, possibly pruned) shape stored in one file: the physical field is pushed down to
/// the format reader and the physical batches are assembled back into logical arrays.
class ShreddingColumnReadPlan {
 public:
    virtual ~ShreddingColumnReadPlan() = default;

    /// The logical field restored on the assembled output.
    virtual const std::shared_ptr<arrow::Field>& LogicalField() const = 0;

    /// The physical file field (possibly a pruned subtree) to read from the file.
    virtual const std::shared_ptr<arrow::Field>& PhysicalField() const = 0;

    /// Assembles the physical column array back into the logical column array.
    virtual Result<std::shared_ptr<arrow::Array>> Assemble(
        const std::shared_ptr<arrow::Array>& physical, arrow::MemoryPool* pool) const = 0;
};

}  // namespace paimon