rocksdb/utilities/blob_db/blob_log_reader.cc

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// 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).
//
#ifndef ROCKSDB_LITE
#include "utilities/blob_db/blob_log_reader.h"
#include <algorithm>
#include "monitoring/statistics.h"
#include "util/file_reader_writer.h"
#include "util/stop_watch.h"
namespace rocksdb {
namespace blob_db {
Reader::Reader(unique_ptr<RandomAccessFileReader>&& file_reader, Env* env,
Statistics* statistics)
: file_(std::move(file_reader)),
env_(env),
statistics_(statistics),
buffer_(),
next_byte_(0) {}
Status Reader::ReadSlice(uint64_t size, Slice* slice, std::string* buf) {
StopWatch read_sw(env_, statistics_, BLOB_DB_BLOB_FILE_READ_MICROS);
buf->reserve(size);
Status s = file_->Read(next_byte_, size, slice, &(*buf)[0]);
next_byte_ += size;
if (!s.ok()) {
return s;
}
RecordTick(statistics_, BLOB_DB_BLOB_FILE_BYTES_READ, slice->size());
if (slice->size() != size) {
return Status::Corruption("EOF reached while reading record");
}
return s;
}
Status Reader::ReadHeader(BlobLogHeader* header) {
assert(file_.get() != nullptr);
assert(next_byte_ == 0);
Status s = ReadSlice(BlobLogHeader::kSize, &buffer_, &backing_store_);
if (!s.ok()) {
return s;
}
if (buffer_.size() != BlobLogHeader::kSize) {
return Status::Corruption("EOF reached before file header");
}
return header->DecodeFrom(buffer_);
}
Status Reader::ReadRecord(BlobLogRecord* record, ReadLevel level,
uint64_t* blob_offset) {
Status s = ReadSlice(BlobLogRecord::kHeaderSize, &buffer_, &backing_store_);
if (!s.ok()) {
return s;
}
if (buffer_.size() != BlobLogRecord::kHeaderSize) {
return Status::Corruption("EOF reached before record header");
}
s = record->DecodeHeaderFrom(buffer_);
if (!s.ok()) {
return s;
}
uint64_t kb_size = record->key_size + record->value_size;
if (blob_offset != nullptr) {
*blob_offset = next_byte_ + record->key_size;
}
switch (level) {
case kReadHeader:
next_byte_ += kb_size;
break;
case kReadHeaderKey:
s = ReadSlice(record->key_size, &record->key, &record->key_buf);
next_byte_ += record->value_size;
break;
case kReadHeaderKeyBlob:
s = ReadSlice(record->key_size, &record->key, &record->key_buf);
if (s.ok()) {
s = ReadSlice(record->value_size, &record->value, &record->value_buf);
}
if (s.ok()) {
s = record->CheckBlobCRC();
}
break;
}
return s;
}
} // namespace blob_db
} // namespace rocksdb
#endif // ROCKSDB_LITE