111 lines
4.9 KiB
Swift
111 lines
4.9 KiB
Swift
import SessionUtilitiesKit
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public enum MessageReceiver {
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public enum Error : LocalizedError {
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case duplicateMessage
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case invalidMessage
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case unknownMessage
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case unknownEnvelopeType
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case noUserPublicKey
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case noData
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case senderBlocked
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case noThread
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case selfSend
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// Shared sender keys
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case invalidGroupPublicKey
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case noGroupPrivateKey
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case sharedSecretGenerationFailed
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public var isRetryable: Bool {
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switch self {
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case .duplicateMessage, .invalidMessage, .unknownMessage, .unknownEnvelopeType, .noData, .senderBlocked, .selfSend: return false
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default: return true
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}
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}
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public var errorDescription: String? {
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switch self {
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case .duplicateMessage: return "Duplicate message."
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case .invalidMessage: return "Invalid message."
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case .unknownMessage: return "Unknown message type."
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case .unknownEnvelopeType: return "Unknown envelope type."
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case .noUserPublicKey: return "Couldn't find user key pair."
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case .noData: return "Received an empty envelope."
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case .senderBlocked: return "Received a message from a blocked user."
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case .noThread: return "Couldn't find thread for message."
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// Shared sender keys
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case .invalidGroupPublicKey: return "Invalid group public key."
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case .noGroupPrivateKey: return "Missing group private key."
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case .sharedSecretGenerationFailed: return "Couldn't generate a shared secret."
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case .selfSend: return "Message addressed at self."
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}
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}
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}
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public static func parse(_ data: Data, openGroupMessageServerID: UInt64?, using transaction: Any) throws -> (Message, SNProtoContent) {
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let userPublicKey = Configuration.shared.storage.getUserPublicKey()
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let isOpenGroupMessage = (openGroupMessageServerID != nil)
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// Parse the envelope
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let envelope = try SNProtoEnvelope.parseData(data)
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let storage = Configuration.shared.storage
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guard !Set(storage.getReceivedMessageTimestamps(using: transaction)).contains(envelope.timestamp) else { throw Error.duplicateMessage }
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storage.addReceivedMessageTimestamp(envelope.timestamp, using: transaction)
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// Decrypt the contents
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let plaintext: Data
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let sender: String
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var groupPublicKey: String? = nil
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if isOpenGroupMessage {
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(plaintext, sender) = (envelope.content!, envelope.source!)
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} else {
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switch envelope.type {
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case .unidentifiedSender: (plaintext, sender) = try decryptWithSignalProtocol(envelope: envelope, using: transaction)
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case .closedGroupCiphertext:
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(plaintext, sender) = try decryptWithSharedSenderKeys(envelope: envelope, using: transaction)
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groupPublicKey = envelope.source
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default: throw Error.unknownEnvelopeType
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}
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}
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// Don't process the envelope any further if the sender is blocked
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guard !isBlocked(sender) else { throw Error.senderBlocked }
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// Ignore self sends
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guard sender != userPublicKey else { throw Error.selfSend }
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// Parse the proto
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let proto: SNProtoContent
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do {
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proto = try SNProtoContent.parseData((plaintext as NSData).removePadding())
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} catch {
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SNLog("Couldn't parse proto due to error: \(error).")
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throw error
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}
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// Parse the message
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let message: Message? = {
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if let readReceipt = ReadReceipt.fromProto(proto) { return readReceipt }
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if let typingIndicator = TypingIndicator.fromProto(proto) { return typingIndicator }
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if let closedGroupUpdate = ClosedGroupUpdate.fromProto(proto) { return closedGroupUpdate }
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if let expirationTimerUpdate = ExpirationTimerUpdate.fromProto(proto) { return expirationTimerUpdate }
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if let visibleMessage = VisibleMessage.fromProto(proto) { return visibleMessage }
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return nil
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}()
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if let message = message {
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if isOpenGroupMessage {
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guard message is VisibleMessage else { throw Error.invalidMessage }
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}
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message.sender = sender
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message.recipient = userPublicKey
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message.sentTimestamp = envelope.timestamp
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message.receivedTimestamp = NSDate.millisecondTimestamp()
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message.groupPublicKey = groupPublicKey
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message.openGroupServerMessageID = openGroupMessageServerID
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var isValid = message.isValid
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if message is VisibleMessage && !isValid && proto.dataMessage?.attachments.isEmpty == false {
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isValid = true
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}
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guard isValid else { throw Error.invalidMessage }
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return (message, proto)
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} else {
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throw Error.unknownMessage
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}
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}
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}
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