1 files changed, 108 insertions, 0 deletions
diff --git a/src/rocksdb/db/blob/blob_file_reader.h b/src/rocksdb/db/blob/blob_file_reader.h
new file mode 100644
index 000000000..75b756da1
--- /dev/null
+++ b/src/rocksdb/db/blob/blob_file_reader.h
@@ -0,0 +1,108 @@
+//  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 <cinttypes>
+#include <memory>
+
+#include "db/blob/blob_read_request.h"
+#include "file/random_access_file_reader.h"
+#include "rocksdb/compression_type.h"
+#include "rocksdb/rocksdb_namespace.h"
+#include "util/autovector.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class Status;
+struct ImmutableOptions;
+struct FileOptions;
+class HistogramImpl;
+struct ReadOptions;
+class Slice;
+class FilePrefetchBuffer;
+class BlobContents;
+class Statistics;
+
+class BlobFileReader {
+ public:
+  static Status Create(const ImmutableOptions& immutable_options,
+                       const FileOptions& file_options,
+                       uint32_t column_family_id,
+                       HistogramImpl* blob_file_read_hist,
+                       uint64_t blob_file_number,
+                       const std::shared_ptr<IOTracer>& io_tracer,
+                       std::unique_ptr<BlobFileReader>* reader);
+
+  BlobFileReader(const BlobFileReader&) = delete;
+  BlobFileReader& operator=(const BlobFileReader&) = delete;
+
+  ~BlobFileReader();
+
+  Status GetBlob(const ReadOptions& read_options, const Slice& user_key,
+                 uint64_t offset, uint64_t value_size,
+                 CompressionType compression_type,
+                 FilePrefetchBuffer* prefetch_buffer,
+                 MemoryAllocator* allocator,
+                 std::unique_ptr<BlobContents>* result,
+                 uint64_t* bytes_read) const;
+
+  // offsets must be sorted in ascending order by caller.
+  void MultiGetBlob(
+      const ReadOptions& read_options, MemoryAllocator* allocator,
+      autovector<std::pair<BlobReadRequest*, std::unique_ptr<BlobContents>>>&
+          blob_reqs,
+      uint64_t* bytes_read) const;
+
+  CompressionType GetCompressionType() const { return compression_type_; }
+
+  uint64_t GetFileSize() const { return file_size_; }
+
+ private:
+  BlobFileReader(std::unique_ptr<RandomAccessFileReader>&& file_reader,
+                 uint64_t file_size, CompressionType compression_type,
+                 SystemClock* clock, Statistics* statistics);
+
+  static Status OpenFile(const ImmutableOptions& immutable_options,
+                         const FileOptions& file_opts,
+                         HistogramImpl* blob_file_read_hist,
+                         uint64_t blob_file_number,
+                         const std::shared_ptr<IOTracer>& io_tracer,
+                         uint64_t* file_size,
+                         std::unique_ptr<RandomAccessFileReader>* file_reader);
+
+  static Status ReadHeader(const RandomAccessFileReader* file_reader,
+                           uint32_t column_family_id, Statistics* statistics,
+                           CompressionType* compression_type);
+
+  static Status ReadFooter(const RandomAccessFileReader* file_reader,
+                           uint64_t file_size, Statistics* statistics);
+
+  using Buffer = std::unique_ptr<char[]>;
+
+  static Status ReadFromFile(const RandomAccessFileReader* file_reader,
+                             uint64_t read_offset, size_t read_size,
+                             Statistics* statistics, Slice* slice, Buffer* buf,
+                             AlignedBuf* aligned_buf,
+                             Env::IOPriority rate_limiter_priority);
+
+  static Status VerifyBlob(const Slice& record_slice, const Slice& user_key,
+                           uint64_t value_size);
+
+  static Status UncompressBlobIfNeeded(const Slice& value_slice,
+                                       CompressionType compression_type,
+                                       MemoryAllocator* allocator,
+                                       SystemClock* clock,
+                                       Statistics* statistics,
+                                       std::unique_ptr<BlobContents>* result);
+
+  std::unique_ptr<RandomAccessFileReader> file_reader_;
+  uint64_t file_size_;
+  CompressionType compression_type_;
+  SystemClock* clock_;
+  Statistics* statistics_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE