xy720 commented on a change in pull request #3878: URL: https://github.com/apache/incubator-doris/pull/3878#discussion_r442327599
########## File path: be/src/exec/buffered_reader.cpp ########## @@ -0,0 +1,162 @@ +// 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/buffered_reader.h" + +#include <sstream> +#include <algorithm> + +#include "common/logging.h" + +namespace doris { + +// buffered reader + +BufferedReader::BufferedReader(FileReader* reader) + : _reader(reader), + _buffer_size(1024 * 1024), + _buffer_offset(0), + _buffer_limit(0), + _cur_offset(0) { + _buffer = new char[_buffer_size]; +} + +BufferedReader::BufferedReader(FileReader* reader, int64_t buffer_size) + : _reader(reader), + _buffer_size(buffer_size), + _buffer_offset(0), + _buffer_limit(0), + _cur_offset(0) { + _buffer = new char[_buffer_size]; +} + +BufferedReader::~BufferedReader() { + close(); +} + +Status BufferedReader::open() { + if (!_reader) { + std::stringstream ss; + ss << "Open buffered reader failed, reader is null"; + LOG(WARNING) << ss.str(); + return Status::InternalError(ss.str()); + } + RETURN_IF_ERROR(_reader->open()); + RETURN_IF_ERROR(fill()); + return Status::OK(); +} + +//not support +Status BufferedReader::read_one_message(uint8_t** buf, size_t* length) { + return Status::NotSupported("Not support"); +} + +Status BufferedReader::read(uint8_t* buf, size_t* buf_len, bool* eof) { + DCHECK_NE(*buf_len, 0); + int64_t bytes_read; + RETURN_IF_ERROR(readat(_cur_offset, (int64_t)*buf_len, &bytes_read, buf)); + if (bytes_read == 0) { + *eof = true; + } else { + *eof = false; + } + return Status::OK(); +} + +Status BufferedReader::readat(int64_t position, int64_t nbytes, int64_t* bytes_read, void* out) { + if (nbytes <= 0) { + *bytes_read = 0; + return Status::OK(); + } + RETURN_IF_ERROR(read_once(position, nbytes, bytes_read, out)); + //EOF + if (*bytes_read <= 0) { + return Status::OK(); + } + while (*bytes_read < nbytes) { + int64_t len; + RETURN_IF_ERROR(read_once(position + *bytes_read, nbytes - *bytes_read, &len, reinterpret_cast<char*>(out) + *bytes_read)); + // EOF + if (len <= 0) { + break; + } + *bytes_read += len; + } + return Status::OK(); +} + +Status BufferedReader::read_once(int64_t position, int64_t nbytes, int64_t* bytes_read, void* out) { + // requested bytes missed the local buffer + if (position >= _buffer_limit || position < _buffer_offset) { + // if requested length is larger than the capacity of buffer, do not + // need to copy the character into local buffer. + if (nbytes > _buffer_limit - _buffer_offset) { + return _reader->readat(position, nbytes, bytes_read, out); + } + _buffer_offset = position; + RETURN_IF_ERROR(fill()); + if (position >= _buffer_limit) { + *bytes_read = 0; + return Status::OK(); + } + } + int64_t len = std::min(_buffer_limit - position, nbytes); + int64_t off = position - _buffer_offset; + memcpy(out, _buffer + off, len); + *bytes_read = len; + _cur_offset = position + *bytes_read; + return Status::OK(); +} + +Status BufferedReader::fill() { + if (_buffer_offset >= 0) { + int64_t bytes_read; + int retry_times = 1; Review comment: ok ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
