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rocksdb/db/blob/blob_file_meta.h

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6.3 KiB

// 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 <cassert>
#include <iosfwd>
#include <memory>
#include <string>
#include <unordered_set>
#include "rocksdb/rocksdb_namespace.h"
namespace ROCKSDB_NAMESPACE {
// SharedBlobFileMetaData represents the immutable part of blob files' metadata,
// like the blob file number, total number and size of blobs, or checksum
// method and value. There is supposed to be one object of this class per blob
// file (shared across all versions that include the blob file in question);
// hence, the type is neither copyable nor movable. A blob file can be marked
// obsolete when the corresponding SharedBlobFileMetaData object is destroyed.
class SharedBlobFileMetaData {
public:
static std::shared_ptr<SharedBlobFileMetaData> Create(
uint64_t blob_file_number, uint64_t total_blob_count,
uint64_t total_blob_bytes, std::string checksum_method,
std::string checksum_value) {
return std::shared_ptr<SharedBlobFileMetaData>(new SharedBlobFileMetaData(
blob_file_number, total_blob_count, total_blob_bytes,
std::move(checksum_method), std::move(checksum_value)));
}
template <typename Deleter>
static std::shared_ptr<SharedBlobFileMetaData> Create(
uint64_t blob_file_number, uint64_t total_blob_count,
uint64_t total_blob_bytes, std::string checksum_method,
std::string checksum_value, Deleter deleter) {
return std::shared_ptr<SharedBlobFileMetaData>(
new SharedBlobFileMetaData(blob_file_number, total_blob_count,
total_blob_bytes, std::move(checksum_method),
std::move(checksum_value)),
deleter);
}
SharedBlobFileMetaData(const SharedBlobFileMetaData&) = delete;
SharedBlobFileMetaData& operator=(const SharedBlobFileMetaData&) = delete;
SharedBlobFileMetaData(SharedBlobFileMetaData&&) = delete;
SharedBlobFileMetaData& operator=(SharedBlobFileMetaData&&) = delete;
uint64_t GetBlobFileNumber() const { return blob_file_number_; }
uint64_t GetTotalBlobCount() const { return total_blob_count_; }
uint64_t GetTotalBlobBytes() const { return total_blob_bytes_; }
const std::string& GetChecksumMethod() const { return checksum_method_; }
const std::string& GetChecksumValue() const { return checksum_value_; }
std::string DebugString() const;
private:
SharedBlobFileMetaData(uint64_t blob_file_number, uint64_t total_blob_count,
uint64_t total_blob_bytes, std::string checksum_method,
std::string checksum_value)
: blob_file_number_(blob_file_number),
total_blob_count_(total_blob_count),
total_blob_bytes_(total_blob_bytes),
checksum_method_(std::move(checksum_method)),
checksum_value_(std::move(checksum_value)) {
assert(checksum_method_.empty() == checksum_value_.empty());
}
uint64_t blob_file_number_;
uint64_t total_blob_count_;
uint64_t total_blob_bytes_;
std::string checksum_method_;
std::string checksum_value_;
};
std::ostream& operator<<(std::ostream& os,
const SharedBlobFileMetaData& shared_meta);
// BlobFileMetaData contains the part of the metadata for blob files that can
// vary across versions, like the amount of garbage in the blob file. In
// addition, BlobFileMetaData objects point to and share the ownership of the
// SharedBlobFileMetaData object for the corresponding blob file. Similarly to
// SharedBlobFileMetaData, BlobFileMetaData are not copyable or movable. They
// are meant to be jointly owned by the versions in which the blob file has the
// same (immutable *and* mutable) state.
class BlobFileMetaData {
public:
using LinkedSsts = std::unordered_set<uint64_t>;
static std::shared_ptr<BlobFileMetaData> Create(
std::shared_ptr<SharedBlobFileMetaData> shared_meta,
LinkedSsts linked_ssts, uint64_t garbage_blob_count,
uint64_t garbage_blob_bytes) {
return std::shared_ptr<BlobFileMetaData>(
new BlobFileMetaData(std::move(shared_meta), std::move(linked_ssts),
garbage_blob_count, garbage_blob_bytes));
}
BlobFileMetaData(const BlobFileMetaData&) = delete;
BlobFileMetaData& operator=(const BlobFileMetaData&) = delete;
BlobFileMetaData(BlobFileMetaData&&) = delete;
BlobFileMetaData& operator=(BlobFileMetaData&&) = delete;
const std::shared_ptr<SharedBlobFileMetaData>& GetSharedMeta() const {
return shared_meta_;
}
uint64_t GetBlobFileNumber() const {
assert(shared_meta_);
return shared_meta_->GetBlobFileNumber();
}
uint64_t GetTotalBlobCount() const {
assert(shared_meta_);
return shared_meta_->GetTotalBlobCount();
}
uint64_t GetTotalBlobBytes() const {
assert(shared_meta_);
return shared_meta_->GetTotalBlobBytes();
}
const std::string& GetChecksumMethod() const {
assert(shared_meta_);
return shared_meta_->GetChecksumMethod();
}
const std::string& GetChecksumValue() const {
assert(shared_meta_);
return shared_meta_->GetChecksumValue();
}
const LinkedSsts& GetLinkedSsts() const { return linked_ssts_; }
uint64_t GetGarbageBlobCount() const { return garbage_blob_count_; }
uint64_t GetGarbageBlobBytes() const { return garbage_blob_bytes_; }
std::string DebugString() const;
private:
BlobFileMetaData(std::shared_ptr<SharedBlobFileMetaData> shared_meta,
LinkedSsts linked_ssts, uint64_t garbage_blob_count,
uint64_t garbage_blob_bytes)
: shared_meta_(std::move(shared_meta)),
linked_ssts_(std::move(linked_ssts)),
garbage_blob_count_(garbage_blob_count),
garbage_blob_bytes_(garbage_blob_bytes) {
assert(shared_meta_);
assert(garbage_blob_count_ <= shared_meta_->GetTotalBlobCount());
assert(garbage_blob_bytes_ <= shared_meta_->GetTotalBlobBytes());
}
std::shared_ptr<SharedBlobFileMetaData> shared_meta_;
LinkedSsts linked_ssts_;
uint64_t garbage_blob_count_;
uint64_t garbage_blob_bytes_;
};
std::ostream& operator<<(std::ostream& os, const BlobFileMetaData& meta);
} // namespace ROCKSDB_NAMESPACE