// 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 "io/fs/hdfs_file_reader.h"

#include <stdint.h>

#include <algorithm>

#include <filesystem>

#include <ostream>

#include <utility>

#include "bvar/latency_recorder.h"

#include "bvar/reducer.h"

#include "common/compiler_util.h" // IWYU pragma: keep

#include "common/logging.h"

#include "common/metrics/doris_metrics.h"

#include "cpp/sync_point.h"

#include "io/fs/err_utils.h"

#include "io/hdfs_util.h"

#include "runtime/thread_context.h"

#include "runtime/workload_management/io_throttle.h"

#include "service/backend_options.h"

namespace doris::io {

bvar::Adder<uint64_t> hdfs_bytes_read_total("hdfs_file_reader", "bytes_read");

bvar::LatencyRecorder hdfs_bytes_per_read("hdfs_file_reader", "bytes_per_read"); // also QPS

bvar::PerSecond<bvar::Adder<uint64_t>> hdfs_read_througthput("hdfs_file_reader",

                                                             "hdfs_read_throughput",

                                                             &hdfs_bytes_read_total);

namespace {

Result<FileHandleCache::Accessor> get_file(const hdfsFS& fs, const Path& file, int64_t mtime,

                                           int64_t file_size) {

    static FileHandleCache cache(config::max_hdfs_file_handle_cache_num, 16,

                                 config::max_hdfs_file_handle_cache_time_sec);

    bool cache_hit;

    FileHandleCache::Accessor accessor;

    RETURN_IF_ERROR_RESULT(cache.get_file_handle(fs, file.native(), mtime, file_size, false,

                                                 &accessor, &cache_hit));

    return accessor;

}

} // namespace

Result<FileReaderSPtr> HdfsFileReader::create(Path full_path, const hdfsFS& fs, std::string fs_name,

                                              const FileReaderOptions& opts,

                                              RuntimeProfile* profile) {

    auto path = convert_path(full_path, fs_name);

    return get_file(fs, path, opts.mtime, opts.file_size).transform([&](auto&& accessor) {

        return std::make_shared<HdfsFileReader>(std::move(path), std::move(fs_name),

                                                std::move(accessor), profile, opts.mtime);

    });

}

HdfsFileReader::HdfsFileReader(Path path, std::string fs_name, FileHandleCache::Accessor accessor,

                               RuntimeProfile* profile, int64_t mtime)

        : _path(std::move(path)),

          _fs_name(std::move(fs_name)),

          _accessor(std::move(accessor)),

          _profile(profile),

          _mtime(mtime) {

    _handle = _accessor.get();

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

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

    if (_profile != nullptr && is_hdfs(_fs_name)) {

#ifdef USE_HADOOP_HDFS

        const char* hdfs_profile_name = "HdfsIO";

        ADD_TIMER(_profile, hdfs_profile_name);

        _hdfs_profile.total_bytes_read =

                ADD_CHILD_COUNTER(_profile, "TotalBytesRead", TUnit::BYTES, hdfs_profile_name);

        _hdfs_profile.total_local_bytes_read =

                ADD_CHILD_COUNTER(_profile, "TotalLocalBytesRead", TUnit::BYTES, hdfs_profile_name);

        _hdfs_profile.total_short_circuit_bytes_read = ADD_CHILD_COUNTER(

                _profile, "TotalShortCircuitBytesRead", TUnit::BYTES, hdfs_profile_name);

        _hdfs_profile.total_total_zero_copy_bytes_read = ADD_CHILD_COUNTER(

                _profile, "TotalZeroCopyBytesRead", TUnit::BYTES, hdfs_profile_name);

        _hdfs_profile.total_hedged_read =

                ADD_CHILD_COUNTER(_profile, "TotalHedgedRead", TUnit::UNIT, hdfs_profile_name);

        _hdfs_profile.hedged_read_in_cur_thread = ADD_CHILD_COUNTER(

                _profile, "HedgedReadInCurThread", TUnit::UNIT, hdfs_profile_name);

        _hdfs_profile.hedged_read_wins =

                ADD_CHILD_COUNTER(_profile, "HedgedReadWins", TUnit::UNIT, hdfs_profile_name);

#endif

    }

}

HdfsFileReader::~HdfsFileReader() {

    static_cast<void>(close());

}

Status HdfsFileReader::close() {

    bool expected = false;

    if (_closed.compare_exchange_strong(expected, true, std::memory_order_acq_rel)) {

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

    }

    return Status::OK();

}

Status HdfsFileReader::read_at_impl(size_t offset, Slice result, size_t* bytes_read,

                                    const IOContext* io_ctx) {

    auto st = do_read_at_impl(offset, result, bytes_read, io_ctx);

    if (!st.ok()) {

        _handle = nullptr;

        _accessor.destroy();

    }

    return st;

}

#ifdef USE_HADOOP_HDFS

Status HdfsFileReader::do_read_at_impl(size_t offset, Slice result, size_t* bytes_read,

                                       const IOContext* /*io_ctx*/) {

    if (closed()) [[unlikely]] {

        return Status::InternalError("read closed file: {}", _path.native());

    }

    if (_handle == nullptr) [[unlikely]] {

        return Status::InternalError("cached hdfs file handle has been destroyed: {}",

                                     _path.native());

    }

    if (offset > _handle->file_size()) {

        return Status::IOError("offset exceeds file size(offset: {}, file size: {}, path: {})",

                               offset, _handle->file_size(), _path.native());

    }

    size_t bytes_req = result.size;

    char* to = result.data;

    bytes_req = std::min(bytes_req, (size_t)(_handle->file_size() - offset));

    *bytes_read = 0;

    if (UNLIKELY(bytes_req == 0)) {

        return Status::OK();

    }

    LIMIT_REMOTE_SCAN_IO(bytes_read);

    size_t has_read = 0;

    while (has_read < bytes_req) {

        int64_t max_to_read = bytes_req - has_read;

        tSize to_read = static_cast<tSize>(

                std::min(max_to_read, static_cast<int64_t>(std::numeric_limits<tSize>::max())));

        tSize loop_read = hdfsPread(_handle->fs(), _handle->file(), offset + has_read,

                                    to + has_read, to_read);

        {

            [[maybe_unused]] Status error_ret;

            TEST_INJECTION_POINT_RETURN_WITH_VALUE("HdfsFileReader:read_error", error_ret);

        }

        if (loop_read < 0) {

            // invoker maybe just skip Status.NotFound and continue

            // so we need distinguish between it and other kinds of errors

            std::string _err_msg = hdfs_error();

            if (_err_msg.find("No such file or directory") != std::string::npos) {

                return Status::NotFound(_err_msg);

            }

            return Status::InternalError(

                    "Read hdfs file failed. (BE: {}) namenode:{}, path:{}, err: {}",

                    BackendOptions::get_localhost(), _fs_name, _path.string(), _err_msg);

        }

        if (loop_read == 0) {

            break;

        }

        has_read += loop_read;

    }

    *bytes_read = has_read;

    hdfs_bytes_read_total << *bytes_read;

    hdfs_bytes_per_read << *bytes_read;

    return Status::OK();

}

#else

// The hedged read only support hdfsPread().

// TODO: rethink here to see if there are some difference between hdfsPread() and hdfsRead()

Status HdfsFileReader::do_read_at_impl(size_t offset, Slice result, size_t* bytes_read,

                                       const IOContext* /*io_ctx*/) {

    if (closed()) [[unlikely]] {

        return Status::InternalError("read closed file: ", _path.native());

    }

    if (offset > _handle->file_size()) {

        return Status::IOError("offset exceeds file size(offset: {}, file size: {}, path: {})",

                               offset, _handle->file_size(), _path.native());

    }

    int res = hdfsSeek(_handle->fs(), _handle->file(), offset);

    if (res != 0) {

        // invoker maybe just skip Status.NotFound and continue

        // so we need distinguish between it and other kinds of errors

        std::string _err_msg = hdfs_error();

        if (_err_msg.find("No such file or directory") != std::string::npos) {

            return Status::NotFound(_err_msg);

        }

        return Status::InternalError("Seek to offset failed. (BE: {}) offset={}, err: {}",

                                     BackendOptions::get_localhost(), offset, _err_msg);

    }

    size_t bytes_req = result.size;

    char* to = result.data;

    bytes_req = std::min(bytes_req, (size_t)(_handle->file_size() - offset));

    *bytes_read = 0;

    if (UNLIKELY(bytes_req == 0)) {

        return Status::OK();

    }

    LIMIT_REMOTE_SCAN_IO(bytes_read);

    size_t has_read = 0;

    while (has_read < bytes_req) {

        int64_t loop_read = hdfsRead(_handle->fs(), _handle->file(), to + has_read,

                                     static_cast<int32_t>(bytes_req - has_read));

        if (loop_read < 0) {

            // invoker maybe just skip Status.NotFound and continue

            // so we need distinguish between it and other kinds of errors

            std::string _err_msg = hdfs_error();

            if (_err_msg.find("No such file or directory") != std::string::npos) {

                return Status::NotFound(_err_msg);

            }

            return Status::InternalError(

                    "Read hdfs file failed. (BE: {}) namenode:{}, path:{}, err: {}",

                    BackendOptions::get_localhost(), _fs_name, _path.string(), _err_msg);

        }

        if (loop_read == 0) {

            break;

        }

        has_read += loop_read;

    }

    *bytes_read = has_read;

    hdfs_bytes_read_total << *bytes_read;

    hdfs_bytes_per_read << *bytes_read;

    return Status::OK();

}

#endif

void HdfsFileReader::_collect_profile_before_close() {

    if (_profile != nullptr && is_hdfs(_fs_name)) {

#ifdef USE_HADOOP_HDFS

        if (_handle == nullptr) [[unlikely]] {

            return;

        }

        struct hdfsReadStatistics* hdfs_statistics = nullptr;

        auto r = hdfsFileGetReadStatistics(_handle->file(), &hdfs_statistics);

        if (r != 0) {

            LOG(WARNING) << "Failed to run hdfsFileGetReadStatistics(): " << r

                         << ", name node: " << _fs_name;

            return;

        }

        COUNTER_UPDATE(_hdfs_profile.total_bytes_read, hdfs_statistics->totalBytesRead);

        COUNTER_UPDATE(_hdfs_profile.total_local_bytes_read, hdfs_statistics->totalLocalBytesRead);

        COUNTER_UPDATE(_hdfs_profile.total_short_circuit_bytes_read,

                       hdfs_statistics->totalShortCircuitBytesRead);

        COUNTER_UPDATE(_hdfs_profile.total_total_zero_copy_bytes_read,

                       hdfs_statistics->totalZeroCopyBytesRead);

        hdfsFileFreeReadStatistics(hdfs_statistics);

        struct hdfsHedgedReadMetrics* hdfs_hedged_read_statistics = nullptr;

        r = hdfsGetHedgedReadMetrics(_handle->fs(), &hdfs_hedged_read_statistics);

        if (r != 0) {

            LOG(WARNING) << "Failed to run hdfsGetHedgedReadMetrics(): " << r

                         << ", name node: " << _fs_name;

            return;

        }

        COUNTER_UPDATE(_hdfs_profile.total_hedged_read, hdfs_hedged_read_statistics->hedgedReadOps);

        COUNTER_UPDATE(_hdfs_profile.hedged_read_in_cur_thread,

                       hdfs_hedged_read_statistics->hedgedReadOpsInCurThread);

        COUNTER_UPDATE(_hdfs_profile.hedged_read_wins,

                       hdfs_hedged_read_statistics->hedgedReadOpsWin);

        hdfsFreeHedgedReadMetrics(hdfs_hedged_read_statistics);

        hdfsFileClearReadStatistics(_handle->file());

#endif

    }

}

} // namespace doris::io