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#pragma once
#include <Core/Types.h>
namespace DB
{
class IDisk;
using DiskPtr = std::shared_ptr<IDisk>;
class SeekableReadBuffer;
class WriteBuffer;
enum class WriteMode;
struct WriteSettings;
struct ReadSettings;
/// Represents operations of loading from disk or downloading for reading a backup.
/// See also implementations: BackupReaderFile, BackupReaderDisk.
class IBackupReader
{
public:
virtual ~IBackupReader() = default;
virtual bool fileExists(const String & file_name) = 0;
virtual UInt64 getFileSize(const String & file_name) = 0;
virtual std::unique_ptr<SeekableReadBuffer> readFile(const String & file_name) = 0;
/// The function copyFileToDisk() can be much faster than reading the file with readFile() and then writing it to some disk.
/// (especially for S3 where it can use CopyObject to copy objects inside S3 instead of downloading and uploading them).
/// Parameters:
/// `encrypted_in_backup` specify if this file is encrypted in the backup, so it shouldn't be encrypted again while restoring to an encrypted disk.
virtual void copyFileToDisk(const String & path_in_backup, size_t file_size, bool encrypted_in_backup,
DiskPtr destination_disk, const String & destination_path, WriteMode write_mode) = 0;
virtual const ReadSettings & getReadSettings() const = 0;
virtual const WriteSettings & getWriteSettings() const = 0;
virtual size_t getWriteBufferSize() const = 0;
};
/// Represents operations of storing to disk or uploading for writing a backup.
/// See also implementations: BackupWriterFile, BackupWriterDisk
class IBackupWriter
{
public:
virtual ~IBackupWriter() = default;
virtual bool fileExists(const String & file_name) = 0;
virtual UInt64 getFileSize(const String & file_name) = 0;
virtual bool fileContentsEqual(const String & file_name, const String & expected_file_contents) = 0;
virtual std::unique_ptr<WriteBuffer> writeFile(const String & file_name) = 0;
using CreateReadBufferFunction = std::function<std::unique_ptr<SeekableReadBuffer>()>;
virtual void copyDataToFile(const String & path_in_backup, const CreateReadBufferFunction & create_read_buffer, UInt64 start_pos, UInt64 length) = 0;
/// The function copyFileFromDisk() can be much faster than copyDataToFile()
/// (especially for S3 where it can use CopyObject to copy objects inside S3 instead of downloading and uploading them).
/// Parameters:
/// `start_pos` and `length` specify a part of the file on `src_disk` to copy to the backup.
/// `copy_encrypted` specify whether this function should copy encrypted data of the file `src_path` to the backup.
virtual void copyFileFromDisk(const String & path_in_backup, DiskPtr src_disk, const String & src_path,
bool copy_encrypted, UInt64 start_pos, UInt64 length) = 0;
virtual void removeFile(const String & file_name) = 0;
virtual void removeFiles(const Strings & file_names) = 0;
virtual const ReadSettings & getReadSettings() const = 0;
virtual const WriteSettings & getWriteSettings() const = 0;
virtual size_t getWriteBufferSize() const = 0;
};
}
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