Some leftover cleanup for removin net6.0 (npgsql#5949)

Part of npgsql#5946

Author: roji

src/Npgsql/Internal/Converters/Primitive/GuidUuidConverter.cs

@@ -21,30 +21,4 @@ protected override void WriteCore(PgWriter writer, Guid value)
         value.TryWriteBytes(bytes, bigEndian: true, out _);
         writer.WriteBytes(bytes);
     }
-
-#if !NET8_0_OR_GREATER
-    // The following table shows .NET GUID vs Postgres UUID (RFC 4122) layouts.
-    //
-    // Note that the first fields are converted from/to native endianness (handled by the Read*
-    // and Write* methods), while the last field is always read/written in big-endian format.
-    //
-    // We're reverting endianness on little endian systems to get it into big endian format.
-    //
-    // | Bits | Bytes | Name  | Endianness (GUID) | Endianness (RFC 4122) |
-    // | ---- | ----- | ----- | ----------------- | --------------------- |
-    // | 32   | 4     | Data1 | Native            | Big                   |
-    // | 16   | 2     | Data2 | Native            | Big                   |
-    // | 16   | 2     | Data3 | Native            | Big                   |
-    // | 64   | 8     | Data4 | Big               | Big                   |
-    [StructLayout(LayoutKind.Explicit)]
-    struct GuidRaw
-    {
-        [FieldOffset(0)] public Guid Value;
-        [FieldOffset(0)] public int Data1;
-        [FieldOffset(4)] public short Data2;
-        [FieldOffset(6)] public short Data3;
-        [FieldOffset(8)] public long Data4;
-        public GuidRaw(Guid value) : this() => Value = value;
-    }
-#endif
 }

src/Npgsql/Internal/NpgsqlConnector.Auth.cs

@@ -255,17 +255,7 @@ static byte[] Xor(byte[] buffer1, byte[] buffer2)
         return buffer1;
     }
 
-    static byte[] HMAC(byte[] key, string data)
-    {
-        var dataBytes = Encoding.UTF8.GetBytes(data);
-#if NET7_0_OR_GREATER
-        return HMACSHA256.HashData(key, dataBytes);
-#else
-        using var ih = IncrementalHash.CreateHMAC(HashAlgorithmName.SHA256, key);
-        ih.AppendData(dataBytes);
-        return ih.GetHashAndReset();
-#endif
-    }
+    static byte[] HMAC(byte[] key, string data) => HMACSHA256.HashData(key, Encoding.UTF8.GetBytes(data));
 
     async Task AuthenticateMD5(string username, byte[] salt, bool async, CancellationToken cancellationToken = default)
     {
@@ -298,11 +288,7 @@ async Task AuthenticateMD5(string username, byte[] salt, bool async, Cancellatio
             prehashbytes.CopyTo(cryptBuf, 0);
 
             sb = new StringBuilder("md5");
-#if NET7_0_OR_GREATER
             hashResult = MD5.HashData(cryptBuf);
-#else
-            hashResult = md5.ComputeHash(cryptBuf);
-#endif
             foreach (var b in hashResult)
                 sb.Append(b.ToString("x2"));
 

src/Npgsql/Internal/NpgsqlConnector.cs

@@ -392,10 +392,7 @@ internal NpgsqlConnector(NpgsqlDataSource dataSource, NpgsqlConnection conn)
         CopyLogger = LoggingConfiguration.CopyLogger;
 
         SslClientAuthenticationOptionsCallback = dataSource.SslClientAuthenticationOptionsCallback;
-
-#if NET7_0_OR_GREATER
         NegotiateOptionsCallback = dataSource.Configuration.NegotiateOptionsCallback;
-#endif
 
         State = ConnectorState.Closed;
         TransactionStatus = TransactionStatus.Idle;

src/Npgsql/Internal/ResolverFactories/NetworkTypeInfoResolverFactory.cs

@@ -78,10 +78,7 @@ static TypeInfoMappingCollection AddMappings(TypeInfoMappingCollection mappings)
 
             // cidr
             mappings.AddStructArrayType<NpgsqlCidr>(DataTypeNames.Cidr);
-
-#if NET8_0_OR_GREATER
             mappings.AddStructArrayType<IPNetwork>(DataTypeNames.Cidr);
-#endif
 
             return mappings;
         }

src/Npgsql/MetricsReporter.cs

@@ -242,11 +242,4 @@ public void Dispose()
             Reporters.Remove(this);
         }
     }
-
-#if !NET7_0_OR_GREATER
-    const long TicksPerMicrosecond = 10;
-    const long TicksPerMillisecond = TicksPerMicrosecond * 1000;
-    const long TicksPerSecond = TicksPerMillisecond * 1000;   // 10,000,000
-    static readonly double StopWatchTickFrequency = (double)TicksPerSecond / Stopwatch.Frequency;
-#endif
 }

src/Npgsql/NpgsqlSlimDataSourceBuilder.cs

@@ -341,7 +341,6 @@ public NpgsqlSlimDataSourceBuilder UsePasswordProvider(
         return this;
     }
 
-#if NET7_0_OR_GREATER
     /// <summary>
     /// When using Kerberos, this is a callback that allows customizing default settings for Kerberos authentication.
     /// </summary>
@@ -358,7 +357,6 @@ public NpgsqlSlimDataSourceBuilder UseNegotiateOptionsCallback(Action<NegotiateA
 
         return this;
     }
-#endif
 
     #endregion Authentication
 

src/Npgsql/PostgresException.cs

@@ -141,9 +141,7 @@ internal PostgresException(SerializationInfo info, StreamingContext context)
     /// </summary>
     /// <param name="info">The <see cref="SerializationInfo"/> to populate with data.</param>
     /// <param name="context">The destination (see <see cref="StreamingContext"/>) for this serialization.</param>
-#if NET8_0_OR_GREATER
     [Obsolete("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.")]
-#endif
     public override void GetObjectData(SerializationInfo info, StreamingContext context)
     {
         base.GetObjectData(info, context);