mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-30 04:41:49 +00:00
4b18c46d10
Summary: Removed confusing, awkward, and undocumented internal API ReadOneLine and replaced with very simple LineFileReader. In refactoring backupable_db.cc, this has the side benefit of removing the arbitrary cap on the size of backup metadata files. Also added Status::MustCheck to make it easy to mark a Status as "must check." Using this, I can ensure that after LineFileReader::ReadLine returns false the caller checks GetStatus(). Also removed some excessive conditional compilation in status.h Pull Request resolved: https://github.com/facebook/rocksdb/pull/8026 Test Plan: added unit test, and running tests with ASSERT_STATUS_CHECKED Reviewed By: mrambacher Differential Revision: D26831687 Pulled By: pdillinger fbshipit-source-id: ef749c265a7a26bb13cd44f6f0f97db2955f6f0f
60 lines
2.3 KiB
C++
60 lines
2.3 KiB
C++
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
|
|
// This source code is licensed under both the GPLv2 (found in the
|
|
// COPYING file in the root directory) and Apache 2.0 License
|
|
// (found in the LICENSE.Apache file in the root directory).
|
|
|
|
#pragma once
|
|
#include <array>
|
|
|
|
#include "file/sequence_file_reader.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
|
|
// A wrapper on top of Env::SequentialFile for reading text lines from a file.
|
|
// Lines are delimited by '\n'. The last line may or may not include a
|
|
// trailing newline. Uses SequentialFileReader internally.
|
|
class LineFileReader {
|
|
private:
|
|
std::array<char, 8192> buf_;
|
|
SequentialFileReader sfr_;
|
|
Status status_;
|
|
const char* buf_begin_ = buf_.data();
|
|
const char* buf_end_ = buf_.data();
|
|
size_t line_number_ = 0;
|
|
bool at_eof_ = false;
|
|
|
|
public:
|
|
// See SequentialFileReader constructors
|
|
template <typename... Args>
|
|
explicit LineFileReader(Args&&... args)
|
|
: sfr_(std::forward<Args&&>(args)...) {}
|
|
|
|
static Status Create(const std::shared_ptr<FileSystem>& fs,
|
|
const std::string& fname, const FileOptions& file_opts,
|
|
std::unique_ptr<LineFileReader>* reader,
|
|
IODebugContext* dbg);
|
|
|
|
LineFileReader(const LineFileReader&) = delete;
|
|
LineFileReader& operator=(const LineFileReader&) = delete;
|
|
|
|
// Reads another line from the file, returning true on success and saving
|
|
// the line to `out`, without delimiter, or returning false on failure. You
|
|
// must check GetStatus() to determine whether the failure was just
|
|
// end-of-file (OK status) or an I/O error (another status).
|
|
bool ReadLine(std::string* out);
|
|
|
|
// Returns the number of the line most recently returned from ReadLine.
|
|
// Return value is unspecified if ReadLine has returned false due to
|
|
// I/O error. After ReadLine returns false due to end-of-file, return
|
|
// value is the last returned line number, or equivalently the total
|
|
// number of lines returned.
|
|
size_t GetLineNumber() const { return line_number_; }
|
|
|
|
// Returns any error encountered during read. The error is considered
|
|
// permanent and no retry or recovery is attempted with the same
|
|
// LineFileReader.
|
|
const Status& GetStatus() const { return status_; }
|
|
};
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|