// 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/sink/writer/async_result_writer.h"

#include "common/status.h"

#include "core/block/block.h"

#include "core/block/materialize_block.h"

#include "exec/pipeline/dependency.h"

#include "exprs/vexpr_context.h"

#include "runtime/exec_env.h"

#include "runtime/fragment_mgr.h"

#include "runtime/runtime_state.h"

namespace doris {

class ObjectPool;

class RowDescriptor;

class TExpr;

AsyncResultWriter::AsyncResultWriter(const doris::VExprContextSPtrs& output_expr_ctxs,

                                     std::shared_ptr<Dependency> dep,

                                     std::shared_ptr<Dependency> fin_dep)

        : _vec_output_expr_ctxs(output_expr_ctxs), _dependency(dep), _finish_dependency(fin_dep) {}

Status AsyncResultWriter::sink(Block* block, bool eos) {

    auto rows = block->rows();

    std::unique_ptr<Block> add_block;

    if (rows) {

        add_block = _get_free_block(block, rows);

    }

    std::lock_guard l(_m);

    // if io task failed, just return error status to

    // end the query

    if (!_writer_status.ok()) {

        return _writer_status.status();

    }

    DCHECK(_dependency);

    if (_is_finished()) {

        _dependency->set_ready();

    }

    if (rows) {

        _memory_used_counter->update(add_block->allocated_bytes());

        _data_queue.emplace_back(std::move(add_block));

        if (!_data_queue_is_available() && !_is_finished()) {

            _dependency->block();

        }

    }

    // in 'process block' we check _eos first and _data_queue second so here

    // in the lock. must modify the _eos after change _data_queue to make sure

    // not lead the logic error in multi thread

    _eos = eos;

    _cv.notify_one();

    return Status::OK();

}

std::unique_ptr<Block> AsyncResultWriter::_get_block_from_queue() {

    std::lock_guard l(_m);

    DCHECK(!_data_queue.empty());

    auto block = std::move(_data_queue.front());

    _data_queue.pop_front();

    DCHECK(_dependency);

    if (_data_queue_is_available()) {

        _dependency->set_ready();

    }

    _memory_used_counter->update(-block->allocated_bytes());

    return block;

}

Status AsyncResultWriter::start_writer(RuntimeState* state, RuntimeProfile* operator_profile) {

    // Attention!!!

    // AsyncResultWriter::open is called asynchronously,

    // so we need to setupt the operator_profile and memory counter here,

    // or else the counter can be nullptr when AsyncResultWriter::sink is called.

    _operator_profile = operator_profile;

    DCHECK(_operator_profile->get_child("CommonCounters") != nullptr);

    _memory_used_counter =

            _operator_profile->get_child("CommonCounters")->get_counter("MemoryUsage");

    DCHECK(_memory_used_counter != nullptr);

    // Should set to false here, to

    DCHECK(_finish_dependency);

    _finish_dependency->block();

    // This is a async thread, should lock the task ctx, to make sure runtimestate and operator_profile

    // not deconstructed before the thread exit.

    auto task_ctx = state->get_task_execution_context();

    RETURN_IF_ERROR(ExecEnv::GetInstance()->fragment_mgr()->get_thread_pool()->submit_func(

            [this, state, operator_profile, task_ctx]() {

                SCOPED_ATTACH_TASK(state);

                auto task_lock = task_ctx.lock();

                if (task_lock == nullptr) {

                    return;

                }

                this->process_block(state, operator_profile);

                task_lock.reset();

            }));

    return Status::OK();

}

void AsyncResultWriter::process_block(RuntimeState* state, RuntimeProfile* operator_profile) {

    if (auto status = open(state, operator_profile); !status.ok()) {

        force_close(status);

    }

    if (state && state->get_query_ctx() && state->get_query_ctx()->workload_group()) {

        if (auto cg_ctl_sptr =

                    state->get_query_ctx()->workload_group()->get_cgroup_cpu_ctl_wptr().lock()) {

            Status ret = cg_ctl_sptr->add_thread_to_cgroup();

            if (ret.ok()) {

                std::string wg_tname =

                        "asyc_wr_" + state->get_query_ctx()->workload_group()->name();

                Thread::set_self_name(wg_tname);

            }

        }

    }

    DCHECK(_dependency);

    while (_writer_status.ok()) {

        ThreadCpuStopWatch cpu_time_stop_watch;

        cpu_time_stop_watch.start();

        Defer defer {[&]() {

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

                state->get_query_ctx()->resource_ctx()->cpu_context()->update_cpu_cost_ms(

                        cpu_time_stop_watch.elapsed_time());

            }

        }};

        //1) wait scan operator write data

        {

            std::unique_lock l(_m);

            // When the query is cancelled, _writer_status may be set to error status in force_close method.

            // When the BE process is exit gracefully, the fragment mgr's thread pool will be shutdown,

            // and the async thread will be exit.

            while (!_eos && _data_queue.empty() && _writer_status.ok() &&

                   !ExecEnv::GetInstance()->fragment_mgr()->shutting_down()) {

                // Add 1s to check to avoid lost signal

                _cv.wait_for(l, std::chrono::seconds(1));

            }

            // If writer status is not ok, then we should not change its status to avoid lost the actual error status.

            if (ExecEnv::GetInstance()->fragment_mgr()->shutting_down() && _writer_status.ok()) {

                _writer_status.update(Status::InternalError<false>("FragmentMgr is shutting down"));

            }

            //check if eos or writer error

            if ((_eos && _data_queue.empty()) || !_writer_status.ok()) {

                _data_queue.clear();

                break;

            }

        }

        //2) get the block from  data queue and write to downstream

        auto block = _get_block_from_queue();

        auto status = write(state, *block);

        if (!status.ok()) [[unlikely]] {

            std::unique_lock l(_m);

            _writer_status.update(status);

            if (_is_finished()) {

                _dependency->set_ready();

            }

            break;

        }

        _return_free_block(std::move(block));

    }

    bool need_finish = false;

    {

        // If the last block is sent successfuly, then call finish to clear the buffer or commit

        // transactions.

        // Using lock to make sure the writer status is not modified

        // There is a unique ptr err_msg in Status, if it is modified, the unique ptr

        // maybe released. And it will core because use after free.

        std::lock_guard l(_m);

        if (_writer_status.ok() && _eos) {

            need_finish = true;

        }

    }

    // eos only means the last block is input to the queue and there is no more block to be added,

    // it is not sure that the block is written to stream.

    if (need_finish) {

        // Should not call finish in lock because it may hang, and it will lock _m too long.

        // And get_writer_status will also need this lock, it will block pipeline exec thread.

        Status st = finish(state);

        _writer_status.update(st);

    }

    Status st = Status::OK();

    { st = _writer_status.status(); }

    Status close_st = close(st);

    {

        // If it is already failed before, then not update the write status so that we could get

        // the real reason.

        std::lock_guard l(_m);

        if (_writer_status.ok()) {

            _writer_status.update(close_st);

        }

    }

    // should set _finish_dependency first, as close function maybe blocked by wait_close of execution_timeout

    _set_ready_to_finish();

}

void AsyncResultWriter::_set_ready_to_finish() {

    DCHECK(_finish_dependency);

    _finish_dependency->set_ready();

}

Status AsyncResultWriter::_projection_block(doris::Block& input_block, doris::Block* output_block) {

    Status status = Status::OK();

    if (input_block.rows() == 0) {

        return status;

    }

    RETURN_IF_ERROR(VExprContext::get_output_block_after_execute_exprs(_vec_output_expr_ctxs,

                                                                       input_block, output_block));

    materialize_block_inplace(*output_block);

    return status;

}

void AsyncResultWriter::force_close(Status s) {

    std::lock_guard l(_m);

    _writer_status.update(s);

    DCHECK(_dependency);

    if (_is_finished()) {

        _dependency->set_ready();

    }

    _cv.notify_one();

}

void AsyncResultWriter::_return_free_block(std::unique_ptr<Block> b) {

    if (_low_memory_mode) {

        return;

    }

    const auto allocated_bytes = b->allocated_bytes();

    if (_free_blocks.enqueue(std::move(b))) {

        _memory_used_counter->update(allocated_bytes);

    }

}

std::unique_ptr<Block> AsyncResultWriter::_get_free_block(doris::Block* block, size_t rows) {

    std::unique_ptr<Block> b;

    if (!_free_blocks.try_dequeue(b)) {

        b = block->create_same_struct_block(rows, true);

    } else {

        _memory_used_counter->update(-b->allocated_bytes());

    }

    b->swap(*block);

    return b;

}

template <typename T>

void clear_blocks(moodycamel::ConcurrentQueue<T>& blocks,

                  RuntimeProfile::Counter* memory_used_counter = nullptr);

void AsyncResultWriter::set_low_memory_mode() {

    _low_memory_mode = true;

    clear_blocks(_free_blocks, _memory_used_counter);

}

} // namespace doris