Signal-iOS/SignalServiceKit/MessageBackup/Archivers/MessageBackupProtoArchiver.swift
2024-04-30 10:04:49 -07:00

72 lines
2.6 KiB
Swift

//
// Copyright 2023 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//
import Foundation
public protocol MessageBackupLoggableId {
/// The type, e.g. "TSInteraction" or "ChatItemProto"
var typeLogString: String { get }
/// The identifier, scoped to the type, e.g. TSInteraction.uniqueId
var idLogString: String { get }
}
extension MessageBackup {
/// Note the "multi"; covers the archiving of multiple frames, typically
/// batched by type.
public enum ArchiveMultiFrameResult<AppIdType: MessageBackupLoggableId> {
public typealias ArchiveFrameError = MessageBackup.ArchiveFrameError<AppIdType>
case success
/// We managed to write some frames, but failed for others.
/// Note that some errors _may_ be terminal; the caller should check.
case partialSuccess([ArchiveFrameError])
/// Catastrophic failure, e.g. we failed to read from the database at all
/// for an entire category of frame.
case completeFailure(FatalArchivingError)
}
public enum RestoreFrameResult<ProtoIdType: MessageBackupLoggableId> {
case success
/// We managed to restore some part of the frame, meaning it is represented in our database.
/// For example, we restored a message but dropped some invalid recipients.
/// Generally restoration of other frames can proceed, but the caller can determine
/// whether to stop or not based on the specific error(s).
case partialRestore([RestoreFrameError<ProtoIdType>])
/// Failure to restore the given frame.
/// Generally restoration of other frames can proceed, but the caller can determine
/// whether to stop or not based on the specific error(s).
case failure([RestoreFrameError<ProtoIdType>])
}
}
public protocol MessageBackupProtoArchiver {
}
extension MessageBackupProtoArchiver {
/**
* Helper function to build a frame and write the proto to the backup file in one action
* with standard error handling.
*/
internal static func writeFrameToStream<AppIdType>(
_ stream: MessageBackupProtoOutputStream,
objectId: AppIdType,
frameBuilder: () -> BackupProto.Frame
) -> MessageBackup.ArchiveFrameError<AppIdType>? {
let frame = frameBuilder()
switch stream.writeFrame(frame) {
case .success:
return nil
case .fileIOError(let error):
return .archiveFrameError(.fileIOError(error), objectId)
case .protoSerializationError(let error):
return .archiveFrameError(.protoSerializationError(error), objectId)
}
}
}