Optimize cast check for NpgsqlBatchCommandCollection and NpgsqlParame… (#4820)

vonzshik · web-flow · commit 6c42d51208c2 · 2023-01-12T12:56:20.000+03:00
diff --git a/src/Npgsql/Internal/NpgsqlReadBuffer.cs b/src/Npgsql/Internal/NpgsqlReadBuffer.cs
@@ -2,7 +2,6 @@
 using System.Buffers;
 using System.Buffers.Binary;
 using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net.Sockets;
 using System.Runtime.CompilerServices;
@@ -519,16 +518,16 @@ public int Read(Span<byte> output)
 
     public ValueTask<int> ReadAsync(Memory<byte> output, CancellationToken cancellationToken = default)
     {
-        if (output.Length == 0)
-            return new ValueTask<int>(0);
-
         var readFromBuffer = Math.Min(ReadBytesLeft, output.Length);
         if (readFromBuffer > 0)
         {
             new Span<byte>(Buffer, ReadPosition, readFromBuffer).CopyTo(output.Span);
             ReadPosition += readFromBuffer;
             return new ValueTask<int>(readFromBuffer);
         }
+        
+        if (output.Length == 0)
+            return new ValueTask<int>(0);
 
         return ReadAsyncLong(this, output, cancellationToken);
 
diff --git a/src/Npgsql/NpgsqlBatchCommandCollection.cs b/src/Npgsql/NpgsqlBatchCommandCollection.cs
@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
 using System.Data.Common;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
 
 namespace Npgsql;
 
@@ -81,7 +83,7 @@ NpgsqlBatchCommand IList<NpgsqlBatchCommand>.this[int index]
         set => _list[index] = value;
     }
 
-    /// <inheritdoc/>
+    /// <inheritdoc cref="IList{T}.this" />
     public new NpgsqlBatchCommand this[int index]
     {
         get => _list[index];
@@ -97,8 +99,16 @@ protected override void SetBatchCommand(int index, DbBatchCommand batchCommand)
         => _list[index] = Cast(batchCommand);
 
     static NpgsqlBatchCommand Cast(DbBatchCommand? value)
-        => value is NpgsqlBatchCommand c
-            ? c
-            : throw new InvalidCastException(
-                $"The value \"{value}\" is not of type \"{nameof(NpgsqlBatchCommand)}\" and cannot be used in this batch command collection.");
+    {
+        var castedValue = value as NpgsqlBatchCommand;
+        if (castedValue is null)
+            ThrowInvalidCastException(value);
+
+        return castedValue;
+    }
+
+    [DoesNotReturn]
+    static void ThrowInvalidCastException(DbBatchCommand? value) =>
+        throw new InvalidCastException(
+            $"The value \"{value}\" is not of type \"{nameof(NpgsqlBatchCommand)}\" and cannot be used in this batch command collection.");
 }
diff --git a/src/Npgsql/NpgsqlParameterCollection.cs b/src/Npgsql/NpgsqlParameterCollection.cs
@@ -5,6 +5,7 @@
 using System.Data.Common;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
 using Npgsql.TypeMapping;
 using NpgsqlTypes;
 
@@ -565,7 +566,7 @@ public override void AddRange(Array values)
             throw new ArgumentNullException(nameof(values));
 
         foreach (var parameter in values)
-            Add(Cast(parameter) ?? throw new ArgumentException("Collection contains a null value.", nameof(values)));
+            Add(Cast(parameter));
     }
 
     /// <inheritdoc />
@@ -748,10 +749,18 @@ internal void ProcessParameters(TypeMapper typeMapper, bool validateValues, Comm
     internal PlaceholderType PlaceholderType { get; set; }
 
     static NpgsqlParameter Cast(object? value)
-        => value is NpgsqlParameter p
-            ? p
-            : throw new InvalidCastException(
-                $"The value \"{value}\" is not of type \"{nameof(NpgsqlParameter)}\" and cannot be used in this parameter collection.");
+    {
+        var castedValue = value as NpgsqlParameter;
+        if (castedValue is null)
+            ThrowInvalidCastException(value);
+
+        return castedValue;
+    }
+
+    [DoesNotReturn]
+    static void ThrowInvalidCastException(object? value) =>
+        throw new InvalidCastException(
+            $"The value \"{value}\" is not of type \"{nameof(NpgsqlParameter)}\" and cannot be used in this parameter collection.");
 }
 
 enum PlaceholderType
