92 lines
2.9 KiB
Swift
92 lines
2.9 KiB
Swift
//
|
|
// Copyright 2023 Signal Messenger, LLC
|
|
// SPDX-License-Identifier: AGPL-3.0-only
|
|
//
|
|
|
|
extension MessageBackup {
|
|
public enum ProtoOutputStreamWriteResult {
|
|
case success
|
|
/// Unable to serialize the provided proto object.
|
|
/// Should never happen, and catastrophic if it does.
|
|
case protoSerializationError(Swift.Error)
|
|
/// Failure writing at file I/O level.
|
|
case fileIOError(Swift.Error)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Output stream for reading and writing a backup file on disk.
|
|
*
|
|
* The backup file is just a sequence of serialized proto bytes, back to back, delimited by varint
|
|
* byte sizes so we know how much to read into memory to deserialize the next proto.
|
|
* The output stream abstracts over this, and allows callers to just think in terms of "frames",
|
|
* the individual proto objects that we write one at a time.
|
|
*/
|
|
public protocol MessageBackupProtoOutputStream {
|
|
|
|
/// Write a header (BakckupInfo) to the backup file.
|
|
/// It is the caller's responsibility to ensure this is always written, and is the first thing written,
|
|
/// in order to produce a valid backup file.
|
|
func writeHeader(_ header: BackupProto_BackupInfo) -> MessageBackup.ProtoOutputStreamWriteResult
|
|
|
|
var numberOfWrittenFrames: UInt64 { get }
|
|
|
|
/// Write a frame to the backup file.
|
|
func writeFrame(_ frame: BackupProto_Frame) -> MessageBackup.ProtoOutputStreamWriteResult
|
|
|
|
/// Closes the output stream.
|
|
func closeFileStream() throws
|
|
}
|
|
|
|
internal class MessageBackupProtoOutputStreamImpl: MessageBackupProtoOutputStream {
|
|
|
|
private let outputStream: OutputStreamable
|
|
private let progress: MessageBackupExportProgress
|
|
|
|
internal init(
|
|
outputStream: OutputStreamable,
|
|
progress: MessageBackupExportProgress
|
|
) {
|
|
self.outputStream = outputStream
|
|
self.progress = progress
|
|
}
|
|
|
|
public private(set) var numberOfWrittenFrames: UInt64 = 0
|
|
|
|
internal func writeHeader(_ header: BackupProto_BackupInfo) -> MessageBackup.ProtoOutputStreamWriteResult {
|
|
let bytes: Data
|
|
do {
|
|
bytes = try header.serializedData()
|
|
} catch {
|
|
return .protoSerializationError(error)
|
|
}
|
|
do {
|
|
try outputStream.write(data: bytes)
|
|
} catch {
|
|
return .fileIOError(error)
|
|
}
|
|
progress.didExportFrame()
|
|
return .success
|
|
}
|
|
|
|
internal func writeFrame(_ frame: BackupProto_Frame) -> MessageBackup.ProtoOutputStreamWriteResult {
|
|
let bytes: Data
|
|
do {
|
|
bytes = try frame.serializedData()
|
|
} catch {
|
|
return .protoSerializationError(error)
|
|
}
|
|
do {
|
|
try outputStream.write(data: bytes)
|
|
} catch {
|
|
return .fileIOError(error)
|
|
}
|
|
numberOfWrittenFrames += 1
|
|
progress.didExportFrame()
|
|
return .success
|
|
}
|
|
|
|
public func closeFileStream() throws {
|
|
try? outputStream.close()
|
|
}
|
|
}
|