session-ios/SessionMessagingKit/Sending & Receiving/MessageReceiver.swift

55 lines
2.1 KiB
Swift

import SessionUtilities
internal enum MessageReceiver {
internal enum Error : LocalizedError {
case invalidMessage
case unknownMessage
// Shared sender keys
case invalidGroupPublicKey
case noData
case noGroupPrivateKey
case sharedSecretGenerationFailed
case selfSend
internal var errorDescription: String? {
switch self {
case .invalidMessage: return "Invalid message."
case .unknownMessage: return "Unknown message type."
// Shared sender keys
case .invalidGroupPublicKey: return "Invalid group public key."
case .noData: return "Received an empty envelope."
case .noGroupPrivateKey: return "Missing group private key."
case .sharedSecretGenerationFailed: return "Couldn't generate a shared secret."
case .selfSend: return "Message addressed at self."
}
}
}
internal static func parse(_ ciphertext: Data) throws -> Message {
let plaintext = ciphertext
let proto: SNProtoContent
do {
proto = try SNProtoContent.parseData(plaintext)
} catch {
SNLog("Couldn't parse proto due to error: \(error).")
throw error
}
let message: Message? = {
if let readReceipt = ReadReceipt.fromProto(proto) { return readReceipt }
if let sessionRequest = SessionRequest.fromProto(proto) { return sessionRequest }
if let typingIndicator = TypingIndicator.fromProto(proto) { return typingIndicator }
if let closedGroupUpdate = ClosedGroupUpdate.fromProto(proto) { return closedGroupUpdate }
if let expirationTimerUpdate = ExpirationTimerUpdate.fromProto(proto) { return expirationTimerUpdate }
if let visibleMessage = VisibleMessage.fromProto(proto) { return visibleMessage }
return nil
}()
if let message = message {
guard message.isValid else { throw Error.invalidMessage }
return message
} else {
throw Error.unknownMessage
}
}
}