// 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.

#include "exec/scan/scanner.h"

#include <glog/logging.h>

#include <algorithm>

#include "common/config.h"

#include "common/status.h"

#include "core/block/column_with_type_and_name.h"

#include "core/column/column_nothing.h"

#include "exec/common/util.hpp"

#include "exec/operator/scan_operator.h"

#include "exec/scan/scan_node.h"

#include "exprs/vexpr_context.h"

#include "exprs/vslot_ref.h"

#include "runtime/descriptors.h"

#include "runtime/runtime_profile.h"

#include "util/concurrency_stats.h"

#include "util/defer_op.h"

namespace doris {

Scanner::Scanner(RuntimeState* state, ScanLocalStateBase* local_state, int64_t limit,

                 RuntimeProfile* profile)

        : _state(state),

          _local_state(local_state),

          _limit(limit),

          _profile(profile),

          _output_tuple_desc(_local_state->output_tuple_desc()),

          _output_row_descriptor(_local_state->_parent->output_row_descriptor()),

          _has_prepared(false) {

    _total_rf_num = cast_set<int>(_local_state->_helper.runtime_filter_nums());

    DorisMetrics::instance()->scanner_cnt->increment(1);

}

Status Scanner::init(RuntimeState* state, const VExprContextSPtrs& conjuncts) {

    // All scanners share a remaining-limit counter so a LIMIT query can

    // stop once enough rows have been collected across scanners.

    // Key TopN scans have no ordinary scan LIMIT, so each scanner can

    // independently produce its full local top-N.

    _shared_scan_limit = _local_state->shared_scan_limit_ptr();

    if (!conjuncts.empty()) {

        _conjuncts.resize(conjuncts.size());

        for (size_t i = 0; i != conjuncts.size(); ++i) {

            RETURN_IF_ERROR(conjuncts[i]->clone(state, _conjuncts[i]));

        }

    }

    const auto& projections = _local_state->_projections;

    if (!projections.empty()) {

        _projections.resize(projections.size());

        for (size_t i = 0; i != projections.size(); ++i) {

            RETURN_IF_ERROR(projections[i]->clone(state, _projections[i]));

        }

    }

    const auto& intermediate_projections = _local_state->_intermediate_projections;

    if (!intermediate_projections.empty()) {

        _intermediate_projections.resize(intermediate_projections.size());

        for (int i = 0; i < intermediate_projections.size(); i++) {

            _intermediate_projections[i].resize(intermediate_projections[i].size());

            for (int j = 0; j < intermediate_projections[i].size(); j++) {

                RETURN_IF_ERROR(intermediate_projections[i][j]->clone(

                        state, _intermediate_projections[i][j]));

            }

        }

    }

    // Pure slot-ref projections do not compute new values; they only reorder or forward scan

    // columns. Record the source column ids once here so the hot projection path can move the

    // existing ColumnPtr instead of executing VSlotRef and then mutating it, which would clone

    // the column when the input block still shares the same pointer. Conjuncts are safe for this

    // path because Scanner filters the source block before running output projections.

    if (!_projections.empty() && _intermediate_projections.empty() && _limit <= 0 &&

        _shared_scan_limit == nullptr && _output_row_descriptor != nullptr &&

        _output_row_descriptor->num_materialized_slots() == _projections.size()) {

        std::vector<int> direct_slot_ref_projection_column_ids;

        direct_slot_ref_projection_column_ids.reserve(_projections.size());

        for (const auto& projection : _projections) {

            auto slot_ref = std::dynamic_pointer_cast<VSlotRef>(projection->root());

            if (slot_ref == nullptr) {

                direct_slot_ref_projection_column_ids.clear();

                break;

            }

            direct_slot_ref_projection_column_ids.push_back(slot_ref->column_id());

        }

        if (!direct_slot_ref_projection_column_ids.empty()) {

            _direct_slot_ref_projection_column_ids =

                    std::move(direct_slot_ref_projection_column_ids);

        }

    }

    return Status::OK();

}

Status Scanner::get_block_after_projects(RuntimeState* state, Block* block, bool* eos) {

    SCOPED_CONCURRENCY_COUNT(ConcurrencyStatsManager::instance().vscanner_get_block);

    auto& row_descriptor = _local_state->_parent->row_descriptor();

    if (_output_row_descriptor) {

        _origin_block.clear_column_data(row_descriptor.num_materialized_slots());

        const auto min_batch_size = std::max(state->batch_size() / 2, 1);

        const auto block_max_bytes = state->preferred_block_size_bytes();

        while (_padding_block.rows() < min_batch_size && _padding_block.bytes() < block_max_bytes &&

               !*eos) {

            RETURN_IF_ERROR(get_block(state, &_origin_block, eos));

            if (*eos) {

                // For the final block, merge any padding directly and return eos in this call.

                // The merged tail can be larger than the target batch, but each source block is

                // already bounded by the lower scanner.

                RETURN_IF_ERROR(_merge_padding_block());

                _origin_block.clear_column_data(row_descriptor.num_materialized_slots());

                break;

            }

            if (_origin_block.rows() >= min_batch_size) {

                break;

            }

            if (_origin_block.rows() + _padding_block.rows() <= state->batch_size() &&

                _origin_block.bytes() + _padding_block.bytes() <= block_max_bytes) {

                RETURN_IF_ERROR(_merge_padding_block());

                _origin_block.clear_column_data(row_descriptor.num_materialized_slots());

            } else {

                if (_origin_block.rows() < _padding_block.rows()) {

                    _padding_block.swap(_origin_block);

                }

                break;

            }

        }

        if (_origin_block.empty() && !_padding_block.empty()) {

            _padding_block.swap(_origin_block);

        }

        return _do_projections(&_origin_block, block);

    } else {

        return get_block(state, block, eos);

    }

}

Status Scanner::get_block(RuntimeState* state, Block* block, bool* eof) {

    // only empty block should be here

    DCHECK(block->rows() == 0);

    // Stop early if other scanners have already collected enough rows

    // for the SQL LIMIT. Skipped when _shared_scan_limit is null (topn

    // path or no LIMIT).

    if (_shared_scan_limit && _shared_scan_limit->load(std::memory_order_acquire) <= 0) {

        *eof = true;

        return Status::OK();

    }

    // scanner running time

    SCOPED_RAW_TIMER(&_per_scanner_timer);

    int64_t rows_read_threshold = _num_rows_read + config::doris_scanner_row_num;

    if (!block->mem_reuse()) {

        for (auto* const slot_desc : _output_tuple_desc->slots()) {

            block->insert(ColumnWithTypeAndName(slot_desc->get_empty_mutable_column(),

                                                slot_desc->get_data_type_ptr(),

                                                slot_desc->col_name()));

        }

    }

    {

        do {

            // 1. Get input block from scanner

            {

                // get block time

                SCOPED_TIMER(_local_state->_scan_timer);

                RETURN_IF_ERROR(_get_block_impl(state, block, eof));

                if (*eof) {

                    DCHECK(block->rows() == 0);

                    break;

                }

                _num_rows_read += block->rows();

                _num_byte_read += block->allocated_bytes();

            }

            // 2. Filter the output block finally.

            {

                SCOPED_TIMER(_local_state->_filter_timer);

                RETURN_IF_ERROR(_filter_output_block(block));

            }

            // record rows return (after filter) for _limit check

            _num_rows_return += block->rows();

            // Publish progress to the shared counter so peer scanners can

            // observe it. The counter may go negative when several scanners

            // subtract concurrently; that is harmless because the operator's

            // reached_limit() makes the final cut.

            if (_shared_scan_limit && block->rows() > 0) {

                _shared_scan_limit->fetch_sub(block->rows(), std::memory_order_acq_rel);

            }

        } while (!_should_stop && !state->is_cancelled() && block->rows() == 0 && !(*eof) &&

                 _num_rows_read < rows_read_threshold);

    }

    if (state->is_cancelled()) {

        // TODO: Should return the specific ErrorStatus instead of just Cancelled.

        return Status::Cancelled("cancelled");

    }

    *eof = *eof || _should_stop;

    // set eof to true if per scanner limit is reached

    // currently for query: ORDER BY key LIMIT n

    *eof = *eof || (_limit > 0 && _num_rows_return >= _limit);

    *eof = *eof || (_shared_scan_limit && _shared_scan_limit->load(std::memory_order_acquire) <= 0);

    return Status::OK();

}

Status Scanner::_filter_output_block(Block* block) {

    auto old_rows = block->rows();

    Status st = VExprContext::filter_block(_conjuncts, block, block->columns());

    _counter.num_rows_unselected += old_rows - block->rows();

    return st;

}

Status Scanner::_do_projections(Block* origin_block, Block* output_block) {

    SCOPED_RAW_TIMER(&_per_scanner_timer);

    SCOPED_RAW_TIMER(&_projection_timer);

    const size_t rows = origin_block->rows();

    if (rows == 0) {

        return Status::OK();

    }

    Block input_block = *origin_block;

    std::vector<int> result_column_ids;

    for (auto& projections : _intermediate_projections) {

        result_column_ids.resize(projections.size());

        for (int i = 0; i < projections.size(); i++) {

            RETURN_IF_ERROR(projections[i]->execute(&input_block, &result_column_ids[i]));

        }

        input_block.shuffle_columns(result_column_ids);

    }

    DCHECK_EQ(rows, input_block.rows());

    // Fast path for the common scan shape: PhysicalProject only forwards slot refs and the

    // output slot type is exactly the same as the scan column type. The exact type check keeps

    // casts/nullability changes on the generic expression path; only a pure column ownership

    // transfer is handled here.

    if (!_direct_slot_ref_projection_column_ids.empty() &&

        _direct_slot_ref_projection_column_ids.size() == _projections.size()) {

        bool can_use_direct_projection = true;

        auto direct_projection_columns =

                VectorizedUtils::create_columns_with_type_and_name(*_output_row_descriptor);

        if (direct_projection_columns.size() != _direct_slot_ref_projection_column_ids.size()) {

            return Status::InternalError(

                    "direct slot ref projection size mismatch, output columns {}, projections {}",

                    direct_projection_columns.size(),

                    _direct_slot_ref_projection_column_ids.size());

        }

        for (size_t i = 0; i < _direct_slot_ref_projection_column_ids.size(); ++i) {

            auto column_id = _direct_slot_ref_projection_column_ids[i];

            if (column_id < 0 || column_id >= origin_block->columns()) {

                return Status::InternalError(

                        "slot ref projection column id {} is out of range, origin block columns {}",

                        column_id, origin_block->columns());

            }

            const auto& src = origin_block->get_by_position(column_id);

            if (!direct_projection_columns[i].type->equals(*src.type)) {

                can_use_direct_projection = false;

                break;

            }

        }

        if (can_use_direct_projection) {

            return _do_direct_slot_ref_projection(origin_block, output_block,

                                                  std::move(direct_projection_columns));

        }

    }

    auto scoped_mutable_block = VectorizedUtils::build_scoped_mutable_mem_reuse_block(

            output_block, *_output_row_descriptor);

    auto& mutable_block = scoped_mutable_block.mutable_block();

    auto& mutable_columns = mutable_block.mutable_columns();

    DCHECK_EQ(mutable_columns.size(), _projections.size());

    for (int i = 0; i < mutable_columns.size(); ++i) {

        ColumnPtr column_ptr;

        RETURN_IF_ERROR(_projections[i]->execute(&input_block, column_ptr));

        column_ptr = column_ptr->convert_to_full_column_if_const();

        if (mutable_columns[i]->is_nullable() != column_ptr->is_nullable()) {

            throw Exception(ErrorCode::INTERNAL_ERROR, "Nullable mismatch");

        }

        mutable_columns[i] = IColumn::mutate(std::move(column_ptr));

    }

    scoped_mutable_block.restore();

    // origin columns was moved into output_block, so we need to set origin_block to empty columns

    auto empty_columns = origin_block->clone_empty_columns();

    origin_block->set_columns(std::move(empty_columns));

    DCHECK_EQ(output_block->rows(), rows);

    return Status::OK();

}

Status Scanner::_do_direct_slot_ref_projection(Block* origin_block, Block* output_block,

                                               ColumnsWithTypeAndName&& output_columns) {

    const size_t rows = origin_block->rows();

    for (size_t i = 0; i < _direct_slot_ref_projection_column_ids.size(); ++i) {

        auto column_id = _direct_slot_ref_projection_column_ids[i];

        if (column_id < 0 || column_id >= origin_block->columns()) {

            return Status::InternalError(

                    "slot ref projection column id {} is out of range, origin block columns {}",

                    column_id, origin_block->columns());

        }

        auto column =

                origin_block->get_by_position(column_id).column->convert_to_full_column_if_const();

        if (column->size() != rows) {

            return Status::InternalError(

                    "direct slot ref projection result column size {} not equal input rows {}",

                    column->size(), rows);

        }

        output_columns[i].column = std::move(column);

    }

    Block projected_block(std::move(output_columns));

    output_block->swap(projected_block);

    // The output block now owns the scan columns. Replace the origin block with empty columns so

    // later block reuse/destruction does not keep an extra shared reference that would make later

    // mutable paths clone the forwarded columns.

    auto empty_columns = origin_block->clone_empty_columns();

    origin_block->set_columns(std::move(empty_columns));

    DCHECK_EQ(output_block->rows(), rows);

    return Status::OK();

}

Status Scanner::try_append_late_arrival_runtime_filter() {

    if (_applied_rf_num == _total_rf_num) {

        return Status::OK();

    }

    DCHECK(_applied_rf_num < _total_rf_num);

    int arrived_rf_num = 0;

    RETURN_IF_ERROR(_local_state->update_late_arrival_runtime_filter(_state, arrived_rf_num));

    if (arrived_rf_num == _applied_rf_num) {

        // No newly arrived runtime filters, just return;

        return Status::OK();

    }

    // avoid conjunct destroy in used by storage layer

    _conjuncts.clear();

    RETURN_IF_ERROR(_local_state->clone_conjunct_ctxs(_conjuncts));

    _applied_rf_num = arrived_rf_num;

    return Status::OK();

}

Status Scanner::close(RuntimeState* state) {

#ifndef BE_TEST

    COUNTER_UPDATE(_local_state->_scanner_wait_worker_timer, _scanner_wait_worker_timer);

#endif

    return Status::OK();

}

bool Scanner::_try_close() {

    bool expected = false;

    return _is_closed.compare_exchange_strong(expected, true);

}

void Scanner::_collect_profile_before_close() {

    COUNTER_UPDATE(_local_state->_scan_cpu_timer, _scan_cpu_timer);

    COUNTER_UPDATE(_local_state->_rows_read_counter, _num_rows_read);

    // Update stats for load. See _should_update_load_counters() for why this is gated.

    if (_should_update_load_counters()) {

        _state->update_num_rows_load_filtered(_counter.num_rows_filtered);

        _state->update_num_rows_load_unselected(_counter.num_rows_unselected);

    }

}

void Scanner::_update_scan_cpu_timer() {

    int64_t cpu_time = _cpu_watch.elapsed_time();

    _scan_cpu_timer += cpu_time;

    if (_state && _state->get_query_ctx()) {

        _state->get_query_ctx()->resource_ctx()->cpu_context()->update_cpu_cost_ms(cpu_time);

    }

}

} // namespace doris