Avoid some heap allocations

Author: Henr1k80

src/Umbraco.Cms.Api.Delivery/Configuration/ConfigureUmbracoMemberAuthenticationDeliveryApiSwaggerGenOptions.cs

@@ -48,7 +48,7 @@ public void Apply(OpenApiOperation operation, OperationFilterContext context)
                                 Id = AuthSchemeName,
                             }
                         },
-                        new string[] { }
+                        []
                     }
                 }
             };

src/Umbraco.Cms.Api.Management/OpenApi/BackOfficeSecurityRequirementsOperationFilterBase.cs

@@ -38,7 +38,7 @@ public void Apply(OpenApiOperation operation, OperationFilterContext context)
                                 Type = ReferenceType.SecurityScheme,
                                 Id = ManagementApiConfiguration.ApiSecurityName
                             }
-                        }, new string[] { }
+                        }, []
                     }
                 }
             };

src/Umbraco.Core/Composing/TypeFinder.cs

@@ -233,10 +233,7 @@ private IEnumerable<Assembly> GetFilteredAssemblies(
             excludeFromResults = new HashSet<Assembly>();
         }
 
-        if (exclusionFilter == null)
-        {
-            exclusionFilter = new string[] { };
-        }
+        exclusionFilter ??= [];
 
         return GetAllAssemblies()
             .Where(x => excludeFromResults.Contains(x) == false

src/Umbraco.Core/Exceptions/InvalidCompositionException.cs

@@ -35,7 +35,7 @@ public InvalidCompositionException(string contentTypeAlias, string[] propertyTyp
     /// <param name="addedCompositionAlias">The added composition alias.</param>
     /// <param name="propertyTypeAliases">The property type aliases.</param>
     public InvalidCompositionException(string contentTypeAlias, string? addedCompositionAlias, string[] propertyTypeAliases)
-        : this(contentTypeAlias, addedCompositionAlias, propertyTypeAliases, new string[0])
+        : this(contentTypeAlias, addedCompositionAlias, propertyTypeAliases, [])
     {
     }
 

src/Umbraco.Core/Extensions/IntExtensions.cs

@@ -27,8 +27,8 @@ public static void Times(this int n, Action<int> action)
     /// </returns>
     public static Guid ToGuid(this int value)
     {
-        var bytes = new byte[16];
-        BitConverter.GetBytes(value).CopyTo(bytes, 0);
+        Span<byte> bytes = stackalloc byte[16];
+        BitConverter.GetBytes(value).CopyTo(bytes);
         return new Guid(bytes);
     }
 }

src/Umbraco.Core/Extensions/StringExtensions.cs

@@ -152,14 +152,16 @@ public static string ReplaceNonAlphanumericChars(this string input, string repla
 
     public static string ReplaceNonAlphanumericChars(this string input, char replacement)
     {
-        var inputArray = input.ToCharArray();
-        var outputArray = new char[input.Length];
-        for (var i = 0; i < inputArray.Length; i++)
+        var chars = input.ToCharArray();
+        for (var i = 0; i < chars.Length; i++)
         {
-            outputArray[i] = char.IsLetterOrDigit(inputArray[i]) ? inputArray[i] : replacement;
+            if (!char.IsLetterOrDigit(chars[i]))
+            {
+                chars[i] = replacement;
+            }
         }
 
-        return new string(outputArray);
+        return new string(chars);
     }
 
     /// <summary>
@@ -209,7 +211,7 @@ public static string AppendQueryStringToUrl(this string url, params string[] que
 
         var nonEmpty = queryStrings.Where(x => !x.IsNullOrWhiteSpace()).ToArray();
 
-        if (url.Contains("?"))
+        if (url.Contains('?'))
         {
             return url + string.Join("&", nonEmpty).EnsureStartsWith('&');
         }
@@ -692,7 +694,7 @@ public static byte[] UrlTokenDecode(this string input)
 
         if (input.Length == 0)
         {
-            return Array.Empty<byte>();
+            return [];
         }
 
         // calc array size - must be groups of 4
@@ -807,7 +809,7 @@ public static string UrlTokenEncode(this byte[] input)
         }
 
         // replace chars that would cause problems in URLs
-        var chArray = new char[pos];
+        Span<char> chArray = pos <= 1024 ? stackalloc char[pos] : new char[pos];
         for (var i = 0; i < pos; i++)
         {
             var ch = str[i];
@@ -1293,8 +1295,7 @@ internal static Guid CreateGuidFromHash(Guid namespaceId, string name, int versi
         }
 
         // most bytes from the hash are copied straight to the bytes of the new GUID (steps 5-7, 9, 11-12)
-        var newGuid = new byte[16];
-        Array.Copy(hash, 0, newGuid, 0, 16);
+        Span<byte> newGuid = hash.AsSpan()[..16];
 
         // set the four most significant bits (bits 12 through 15) of the time_hi_and_version field to the appropriate 4-bit version number from Section 4.1.3 (step 8)
         newGuid[6] = (byte)((newGuid[6] & 0x0F) | (version << 4));
@@ -1308,20 +1309,15 @@ internal static Guid CreateGuidFromHash(Guid namespaceId, string name, int versi
     }
 
     // Converts a GUID (expressed as a byte array) to/from network order (MSB-first).
-    internal static void SwapByteOrder(byte[] guid)
+    internal static void SwapByteOrder(Span<byte> guid)
     {
         SwapBytes(guid, 0, 3);
         SwapBytes(guid, 1, 2);
         SwapBytes(guid, 4, 5);
         SwapBytes(guid, 6, 7);
     }
 
-    private static void SwapBytes(byte[] guid, int left, int right)
-    {
-        var temp = guid[left];
-        guid[left] = guid[right];
-        guid[right] = temp;
-    }
+    private static void SwapBytes(Span<byte> guid, int left, int right) => (guid[left], guid[right]) = (guid[right], guid[left]);
 
     /// <summary>
     ///     Checks if a given path is a full path including drive letter

src/Umbraco.Core/GuidUtils.cs

@@ -63,7 +63,7 @@ public static string ToBase32String(Guid guid, int length = 26)
         // a Guid is 3 blocks + 8 bits
 
         // so it turns into a 3*8+2 = 26 chars string
-        var chars = new char[length];
+        Span<char> chars = stackalloc char[length];
 
         var i = 0;
         var j = 0;

src/Umbraco.Core/HexEncoder.cs

@@ -28,7 +28,8 @@ public static class HexEncoder
     public static string Encode(byte[] bytes)
     {
         var length = bytes.Length;
-        var chars = new char[length * 2];
+        int charsLength = length * 2;
+        Span<char> chars = charsLength <= 1024 ? stackalloc char[charsLength] : new char[charsLength];
 
         var index = 0;
         for (var i = 0; i < length; i++)
@@ -38,7 +39,7 @@ public static string Encode(byte[] bytes)
             chars[index++] = HexLutLo[byteIndex];
         }
 
-        return new string(chars, 0, chars.Length);
+        return new string(chars);
     }
 
     /// <summary>
@@ -54,7 +55,8 @@ public static string Encode(byte[] bytes)
     public static string Encode(byte[] bytes, char separator, int blockSize, int blockCount)
     {
         var length = bytes.Length;
-        var chars = new char[(length * 2) + blockCount];
+        int charsLength = (length * 2) + blockCount;
+        Span<char> chars = charsLength <= 1024 ? stackalloc char[charsLength] : new char[charsLength];
         var count = 0;
         var size = 0;
         var index = 0;
@@ -80,6 +82,6 @@ public static string Encode(byte[] bytes, char separator, int blockSize, int blo
             count++;
         }
 
-        return new string(chars, 0, chars.Length);
+        return new string(chars);
     }
 }

src/Umbraco.Core/Strings/DefaultShortStringHelper.cs

@@ -306,7 +306,7 @@ protected virtual string CleanString(string text, CleanStringType stringType, st
             return text;
         }
 
-        private string RemoveSurrogatePairs(string text)
+        private static string RemoveSurrogatePairs(string text)
         {
             var input = text.AsSpan();
             Span<char> output = input.Length <= 1024 ? stackalloc char[input.Length] : new char[text.Length];
@@ -622,7 +622,8 @@ public virtual string SplitPascalCasing(string text, char separator)
             }
 
             var input = text.ToCharArray();
-            var output = new char[input.Length * 2];
+            int outputLength = input.Length * 2;
+            Span<char> output = outputLength <= 1024 ? stackalloc char[outputLength] : new char[outputLength];
             var opos = 0;
             var a = input.Length > 0 ? input[0] : char.MinValue;
             var upos = char.IsUpper(a) ? 1 : 0;
@@ -666,7 +667,7 @@ public virtual string SplitPascalCasing(string text, char separator)
                 output[opos++] = a;
             }
 
-            return new string(output, 0, opos);
+            return new string(output[..opos]);
         }
 
         #endregion

src/Umbraco.Core/Strings/Utf8ToAsciiConverter.cs

@@ -50,11 +50,10 @@ public static char[] ToAsciiCharArray(string text, char fail = '?')
 
         // this is faster although it uses more memory
         // but... we should be filtering short strings only...
-        var output = new char[input.Length * 3]; // *3 because of things such as OE
+        int outputLength = input.Length * 3; // *3 because of things such as OE
+        Span<char> output = outputLength <= 1024 ? stackalloc char[outputLength] : new char[outputLength];
         var len = ToAscii(input, output, fail);
-        var array = new char[len];
-        Array.Copy(output, array, len);
-        return array;
+        return output[..len].ToArray();
 
         // var temp = new StringBuilder(input.Length + 16); // default is 16, start with at least input length + little extra
         // ToAscii(input, temp);