Add type-aware REQUEST_SYNC sync rounds (#853)

Co-authored-by: jack <jackjackbits@users.noreply.github.com>
2026-07-25 01:05:19 +00:00 · 2025-10-22 12:24:29 +02:00
parent 98fa02cc16
commit b6ce4fae43
5 changed files with 447 additions and 84 deletions
@@ -0,0 +1,104 @@
+import Foundation
+
+/// Bitfield describing which message types are covered by a REQUEST_SYNC round.
+/// Matches the Android mapping (bit index -> message type).
+struct SyncTypeFlags: OptionSet {
+    let rawValue: UInt64
+
+    init(rawValue: UInt64) {
+        self.rawValue = rawValue & 0x00FF_FFFF_FFFF_FFFF // Trim to max 8 bytes
+    }
+
+    private static func bitIndex(for type: MessageType) -> Int? {
+        switch type {
+        case .announce: return 0
+        case .message: return 1
+        case .leave: return 2
+        case .noiseHandshake: return 3
+        case .noiseEncrypted: return 4
+        case .fragment: return 5
+        case .requestSync: return 6
+        case .fileTransfer: return 7
+        }
+    }
+
+    private static func type(forBit index: Int) -> MessageType? {
+        switch index {
+        case 0: return .announce
+        case 1: return .message
+        case 2: return .leave
+        case 3: return .noiseHandshake
+        case 4: return .noiseEncrypted
+        case 5: return .fragment
+        case 6: return .requestSync
+        case 7: return .fileTransfer
+        default:
+            return nil
+        }
+    }
+
+    static let announce = SyncTypeFlags(messageTypes: [.announce])
+    static let message = SyncTypeFlags(messageTypes: [.message])
+    static let fragment = SyncTypeFlags(messageTypes: [.fragment])
+    static let fileTransfer = SyncTypeFlags(messageTypes: [.fileTransfer])
+
+    static let publicMessages = SyncTypeFlags(messageTypes: [.announce, .message])
+
+    init(messageTypes: [MessageType]) {
+        var raw: UInt64 = 0
+        for type in messageTypes {
+            guard let bit = SyncTypeFlags.bitIndex(for: type) else { continue }
+            raw |= (1 << UInt64(bit))
+        }
+        self.init(rawValue: raw)
+    }
+
+    func contains(_ type: MessageType) -> Bool {
+        guard let bit = SyncTypeFlags.bitIndex(for: type) else { return false }
+        return contains(SyncTypeFlags(rawValue: 1 << UInt64(bit)))
+    }
+
+    func union(_ other: SyncTypeFlags) -> SyncTypeFlags {
+        SyncTypeFlags(rawValue: rawValue | other.rawValue)
+    }
+
+    func intersection(_ other: SyncTypeFlags) -> SyncTypeFlags {
+        SyncTypeFlags(rawValue: rawValue & other.rawValue)
+    }
+
+    func toMessageTypes() -> [MessageType] {
+        guard rawValue != 0 else { return [] }
+        var types: [MessageType] = []
+        for bit in 0..<64 {
+            guard (rawValue & (1 << UInt64(bit))) != 0 else { continue }
+            if let type = SyncTypeFlags.type(forBit: bit) {
+                types.append(type)
+            }
+        }
+        return types
+    }
+
+    func toData() -> Data? {
+        guard rawValue != 0 else { return nil }
+        var value = rawValue
+        var bytes: [UInt8] = []
+        while value > 0 && bytes.count < 8 {
+            bytes.append(UInt8(value & 0xFF))
+            value >>= 8
+        }
+        while let last = bytes.last, last == 0 {
+            bytes.removeLast()
+        }
+        guard !bytes.isEmpty, bytes.count <= 8 else { return nil }
+        return Data(bytes)
+    }
+
+    static func decode(_ data: Data) -> SyncTypeFlags? {
+        guard (1...8).contains(data.count) else { return nil }
+        var raw: UInt64 = 0
+        for (index, byte) in data.enumerated() {
+            raw |= UInt64(byte) << UInt64(index * 8)
+        }
+        return SyncTypeFlags(rawValue: raw)
+    }
+}