Method GetDecryptedPayload

ui/Services/Patching/Patcher.cs:108–146

(string cachePath)

        }

        byte[] GetDecryptedPayload(string cachePath)
        {
            var info = new FileInfo(cachePath);
            if (!info.Exists) return null;

            long size = info.Length;
            var lastWrite = info.LastWriteTimeUtc;
            if (_cachedPayload != null && _cachedPayloadSize == size && _cachedPayloadTime == lastWrite)
                return _cachedPayload;

            byte[] raw;
            try
            {
                using var fs = new FileStream(cachePath, FileMode.Open, FileAccess.Read, FileShare.Read);
                raw = new byte[fs.Length];
                fs.ReadExactly(raw);
            }
            catch (IOException) { return null; }

            if (raw.Length < 32) return null;

            try
            {
                var iv = raw.AsSpan(0, 16).ToArray();
                var ct = raw.AsSpan(16).ToArray();
                var dec = PayloadCrypto.AesCbcDecrypt(ct, AesKey, iv);
                if (dec.Length < 4) return null;
                using var zIn = new ZLibStream(
                    new MemoryStream(dec, 4, dec.Length - 4),
                    CompressionMode.Decompress);
                using var ms = new MemoryStream();
                zIn.CopyTo(ms);
                _cachedPayload = ms.ToArray();
                _cachedPayloadSize = size;
                _cachedPayloadTime = lastWrite;
                return _cachedPayload;
            }
            catch { return null; }
        }

        (byte[] payload, byte[] iv, string error) ReadAndDecryptPayload(string cachePath)
        {