// 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 <fmt/core.h>

#include <cstddef>

#include <cstdint>

#include "common/status.h"

#include "core/block/block.h"

#include "exprs/vexpr_context.h"

namespace doris {

constexpr auto COMBINATOR_SUFFIX_OUTER = "_outer";

class TableFunction {

public:

virtual ~TableFunction() = default;

struct BlockFastPathContext {

const UInt8* array_nullmap_data = nullptr;

const IColumn::Offsets64* offsets_ptr = nullptr;

ColumnPtr nested_col = nullptr;

const UInt8* nested_nullmap_data = nullptr;

bool generate_row_index = false;

};

virtual Status prepare() { return Status::OK(); }

virtual Status open() { return Status::OK(); }

virtual Status process_init(Block* block, RuntimeState* state) = 0;

virtual void process_row(size_t row_idx) {

if (!_is_const) {

_cur_size = 0;

}

reset();

}

// only used for vectorized.

virtual void process_close() = 0;

virtual void reset() {

_eos = false;

_cur_offset = 0;

}

virtual void get_same_many_values(MutableColumnPtr& column, int length = 0) = 0;

virtual int get_value(MutableColumnPtr& column, int max_step) = 0;

virtual bool support_block_fast_path() const { return false; }

virtual Status prepare_block_fast_path(Block* /*block*/, RuntimeState* /*state*/,

BlockFastPathContext* /*ctx*/) {

return Status::NotSupported("table function {} doesn't support block fast path", _fn_name);

}

virtual Status close() { return Status::OK(); }

virtual void forward(int step = 1) {

if (current_empty()) {

_eos = true;

} else {

_cur_offset += step;

if (_cur_offset >= _cur_size) {

_eos = true;

}

}

}

std::string name() const { return _fn_name; }

bool eos() const { return _eos; }

void set_expr_context(const VExprContextSPtr& expr_context) { _expr_context = expr_context; }

void set_nullable() { _is_nullable = true; }

bool is_outer() const { return _is_outer; }

void set_outer() {

if (is_outer()) {

return;

}

_is_outer = true;

_fn_name += COMBINATOR_SUFFIX_OUTER;

}

bool current_empty() const { return _cur_size == 0; }

protected:

std::string _fn_name;

VExprContextSPtr _expr_context = nullptr;

// true if there is no more data can be read from this function.

bool _eos = false;

// the position of current cursor

int64_t _cur_offset = 0;

// the size of current result

int64_t _cur_size = 0;

// set _is_outer to false for explode function, and should not return tuple while array is null or empty

bool _is_outer = false;

bool _is_nullable = false;

bool _is_const = false;

};

} // namespace doris