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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
commit | e6918187568dbd01842d8d1d2c808ce16a894239 (patch) | |
tree | 64f88b554b444a49f656b6c656111a145cbbaa28 /src/rocksdb/db/blob/blob_log_sequential_reader.h | |
parent | Initial commit. (diff) | |
download | ceph-e6918187568dbd01842d8d1d2c808ce16a894239.tar.xz ceph-e6918187568dbd01842d8d1d2c808ce16a894239.zip |
Adding upstream version 18.2.2.upstream/18.2.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/rocksdb/db/blob/blob_log_sequential_reader.h')
-rw-r--r-- | src/rocksdb/db/blob/blob_log_sequential_reader.h | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/rocksdb/db/blob/blob_log_sequential_reader.h b/src/rocksdb/db/blob/blob_log_sequential_reader.h new file mode 100644 index 000000000..98afa8518 --- /dev/null +++ b/src/rocksdb/db/blob/blob_log_sequential_reader.h @@ -0,0 +1,83 @@ +// Copyright (c) 2011-present, Facebook, Inc. 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 <memory> + +#include "db/blob/blob_log_format.h" +#include "rocksdb/slice.h" + +#define MAX_HEADER_SIZE(a, b, c) (a > b ? (a > c ? a : c) : (b > c ? b : c)) + +namespace ROCKSDB_NAMESPACE { + +class RandomAccessFileReader; +class Env; +class Statistics; +class Status; +class SystemClock; + +/** + * BlobLogSequentialReader is a general purpose log stream reader + * implementation. The actual job of reading from the device is implemented by + * the RandomAccessFileReader interface. + * + * Please see BlobLogWriter for details on the file and record layout. + */ + +class BlobLogSequentialReader { + public: + enum ReadLevel { + kReadHeader, + kReadHeaderKey, + kReadHeaderKeyBlob, + }; + + // Create a reader that will return log records from "*file_reader". + BlobLogSequentialReader(std::unique_ptr<RandomAccessFileReader>&& file_reader, + SystemClock* clock, Statistics* statistics); + + // No copying allowed + BlobLogSequentialReader(const BlobLogSequentialReader&) = delete; + BlobLogSequentialReader& operator=(const BlobLogSequentialReader&) = delete; + + ~BlobLogSequentialReader(); + + Status ReadHeader(BlobLogHeader* header); + + // Read the next record into *record. Returns true if read + // successfully, false if we hit end of the input. The contents filled in + // *record will only be valid until the next mutating operation on this + // reader. + // If blob_offset is non-null, return offset of the blob through it. + Status ReadRecord(BlobLogRecord* record, ReadLevel level = kReadHeader, + uint64_t* blob_offset = nullptr); + + Status ReadFooter(BlobLogFooter* footer); + + void ResetNextByte() { next_byte_ = 0; } + + uint64_t GetNextByte() const { return next_byte_; } + + private: + Status ReadSlice(uint64_t size, Slice* slice, char* buf); + + const std::unique_ptr<RandomAccessFileReader> file_; + SystemClock* clock_; + + Statistics* statistics_; + + Slice buffer_; + char header_buf_[MAX_HEADER_SIZE(BlobLogHeader::kSize, BlobLogFooter::kSize, + BlobLogRecord::kHeaderSize)]; + + // which byte to read next + uint64_t next_byte_; +}; + +} // namespace ROCKSDB_NAMESPACE + +#undef MAX_HEADER_SIZE
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