Use StringComparison.Ordinal in hot paths

src/Umbraco.Core/Extensions/UriExtensions.cs

@@ -22,7 +22,7 @@ public static class UriExtensions
     /// <remarks>Everything else remains unchanged, except for the fragment which is removed.</remarks>
     public static Uri Rewrite(this Uri uri, string path)
     {
-        if (path.StartsWith("/") == false)
+        if (path.StartsWith("/", StringComparison.Ordinal) == false)
         {
             throw new ArgumentException("Path must start with a slash.", "path");
         }
@@ -42,12 +42,12 @@ public static Uri Rewrite(this Uri uri, string path)
     /// <remarks>Everything else remains unchanged, except for the fragment which is removed.</remarks>
     public static Uri Rewrite(this Uri uri, string path, string query)
     {
-        if (path.StartsWith("/") == false)
+        if (path.StartsWith("/", StringComparison.Ordinal) == false)
         {
             throw new ArgumentException("Path must start with a slash.", "path");
         }
 
-        if (query.Length > 0 && query.StartsWith("?") == false)
+        if (query.Length > 0 && query.StartsWith("?", StringComparison.Ordinal) == false)
         {
             throw new ArgumentException("Query must start with a question mark.", "query");
         }

src/Umbraco.Core/Routing/DomainUtilities.cs

@@ -388,7 +388,7 @@ private static IReadOnlyCollection<DomainAndUri> SelectByBase(IReadOnlyCollectio
         public static Uri ParseUriFromDomainName(string domainName, Uri currentUri)
         {
             // turn "/en" into "http://whatever.com/en" so it becomes a parseable uri
-            var name = domainName.StartsWith("/") && currentUri != null
+            var name = domainName.StartsWith("/", StringComparison.Ordinal) && currentUri != null
                 ? currentUri.GetLeftPart(UriPartial.Authority) + domainName
                 : domainName;
             var scheme = currentUri?.Scheme ?? Uri.UriSchemeHttp;

src/Umbraco.Core/Routing/NewDefaultUrlProvider.cs

@@ -155,7 +155,7 @@ public virtual IEnumerable<UrlInfo> GetOtherUrls(int id, Uri current)
             }
 
             // need to strip off the leading ID for the route if it exists (occurs if the route is for a node with a domain assigned)
-            var pos = route.IndexOf('/');
+            var pos = route.IndexOf('/', StringComparison.Ordinal);
             var path = pos == 0 ? route : route.Substring(pos);
 
             var uri = new Uri(CombinePaths(d.Uri.GetLeftPart(UriPartial.Path), path));
@@ -237,7 +237,7 @@ private string GetLegacyRouteFormatById(Guid key, string? culture)
 
         // extract domainUri and path
         // route is /<path> or <domainRootId>/<path>
-        var pos = route.IndexOf('/');
+        var pos = route.IndexOf('/', StringComparison.Ordinal);
         var path = pos == 0 ? route : route[pos..];
         DomainAndUri? domainUri = pos == 0
             ? null

src/Umbraco.Core/Routing/PublishedRouter.cs

@@ -440,7 +440,7 @@ internal bool FindTemplateRenderingEngineInDirectory(DirectoryInfo? directory, s
             return false;
         }
 
-        var pos = alias.IndexOf('/');
+        var pos = alias.IndexOf('/', StringComparison.Ordinal);
         if (pos > 0)
         {
             // recurse

src/Umbraco.Core/Routing/UriUtility.cs

@@ -144,7 +144,7 @@ public string ResolveUrl(string relativeUrl)
         var idxOfScheme = relativeUrl.IndexOf(@"://", StringComparison.Ordinal);
         if (idxOfScheme != -1)
         {
-            var idxOfQM = relativeUrl.IndexOf('?');
+            var idxOfQM = relativeUrl.IndexOf('?', StringComparison.Ordinal);
             if (idxOfQM == -1 || idxOfQM > idxOfScheme)
             {
                 return relativeUrl;
@@ -226,7 +226,7 @@ internal Uri ToFullUrl(string absolutePath, Uri curentRequestUrl)
             throw new ArgumentNullException(nameof(absolutePath));
         }
 
-        if (!absolutePath.StartsWith("/"))
+        if (!absolutePath.StartsWith("/", StringComparison.Ordinal))
         {
             throw new FormatException("The absolutePath specified does not start with a '/'");
         }

src/Umbraco.Core/UriUtilityCore.cs

@@ -4,7 +4,7 @@ namespace Umbraco.Cms.Core;
 
 public static class UriUtilityCore
 {
-    public static bool HasScheme(string uri) => uri.IndexOf("://", StringComparison.InvariantCulture) > 0;
+    public static bool HasScheme(string uri) => uri.IndexOf("://", StringComparison.Ordinal) > 0;
 
     public static string StartWithScheme(string uri) => StartWithScheme(uri, null);
 

tests/Umbraco.Tests.Benchmarks/StringIndexOfBenchmarks.cs

@@ -0,0 +1,94 @@
+using BenchmarkDotNet.Attributes;
+using Umbraco.Tests.Benchmarks.Config;
+
+namespace Umbraco.Tests.Benchmarks;
+
+[QuickRunWithMemoryDiagnoserConfig]
+public class StringIndexOfBenchmarks
+{
+    private string _domainName = "https://www.lorem-ipsum.com";
+
+    [Benchmark()]
+    public bool IndexOf_Original()
+    {
+        return _domainName.IndexOf("://") > 0;
+    }
+
+    [Benchmark()]
+    public bool IndexOf_Ordinal()
+    {
+        return _domainName.IndexOf("://", StringComparison.Ordinal) > -1;
+    }
+
+    [Benchmark()]
+    public bool IndexOf_Invariant()
+    {
+        return _domainName.IndexOf("://", StringComparison.InvariantCulture) > -1;
+    }
+
+    [Benchmark()]
+    public bool IndexOf_Span()
+    {
+        return _domainName.AsSpan().IndexOf("://", StringComparison.InvariantCulture) > -1;
+    }
+
+    [Benchmark()]
+    public bool Contains()
+    {
+        return _domainName.Contains("://");
+    }
+
+    [Benchmark()]
+    public bool Contains_Ordinal()
+    {
+        return _domainName.Contains("://", StringComparison.Ordinal);
+    }
+
+    [Benchmark()]
+    public bool Contains_Invariant()
+    {
+        return _domainName.Contains("://", StringComparison.InvariantCulture);
+    }
+
+    [Benchmark()]
+    public bool Contains_Span_Ordinal()
+    {
+        return _domainName.AsSpan().Contains("://", StringComparison.Ordinal);
+    }
+
+    [Benchmark()]
+    public bool Contains_Span_Invariant()
+    {
+        return _domainName.AsSpan().Contains("://", StringComparison.InvariantCulture);
+    }
+
+    [Benchmark()]
+    public bool Span_Index_Of()
+    {
+        var uri = "https://www.lorem-ipsum.com".AsSpan();
+        return uri.IndexOf("#") > -1;
+    }
+
+    [Benchmark()]
+    public bool Span_Index_Of_Ordinal()
+    {
+        var uri = "https://www.lorem-ipsum.com".AsSpan();
+        return uri.IndexOf("#".AsSpan(), StringComparison.Ordinal) > -1;
+    }
+
+    /*
+       | Method                  | Mean       | Error      | StdDev    | Allocated |
+       |------------------------ |-----------:|-----------:|----------:|----------:|
+       | IndexOf_Original        | 916.918 ns | 73.7556 ns | 4.0428 ns |         - |
+       | IndexOf_Ordinal         |   4.083 ns |  1.5083 ns | 0.0827 ns |         - |
+       | IndexOf_Invariant       |  12.941 ns |  3.7574 ns | 0.2060 ns |         - |
+       | IndexOf_Span            |  13.076 ns |  3.0666 ns | 0.1681 ns |         - |
+       | Contains                |   2.828 ns |  0.3648 ns | 0.0200 ns |         - |
+       | Contains_Ordinal        |   4.368 ns |  0.9882 ns | 0.0542 ns |         - |
+       | Contains_Invariant      |  12.986 ns |  2.3526 ns | 0.1290 ns |         - |
+       | Contains_Span_Ordinal   |   2.924 ns |  0.1593 ns | 0.0087 ns |         - |
+       | Contains_Span_Invariant |  12.502 ns |  1.4153 ns | 0.0776 ns |         - |
+       | Span_Index_Of           |   1.741 ns |  0.9093 ns | 0.0498 ns |         - |
+       | Span_Index_Of_Ordinal   |   1.809 ns |  0.3703 ns | 0.0203 ns |         - |
+     */
+}

tests/Umbraco.Tests.Benchmarks/StringStartsWithBenchmarks.cs

@@ -0,0 +1,52 @@
+using BenchmarkDotNet.Attributes;
+using Umbraco.Tests.Benchmarks.Config;
+
+namespace Umbraco.Tests.Benchmarks;
+
+[QuickRunWithMemoryDiagnoserConfig]
+public class StringStartsWithBenchmarks
+{
+
+    private string _domainName = "domain1.com";
+
+    [Benchmark(Baseline = true)]
+    public bool Original()
+    {
+        return _domainName.StartsWith("/");
+    }
+
+    [Benchmark()]
+    public bool Ordinal()
+    {
+        return _domainName.StartsWith("/",StringComparison.Ordinal);
+    }
+
+    [Benchmark()]
+    public bool Invariant()
+    {
+        return _domainName.StartsWith("/", StringComparison.InvariantCulture);
+    }
+
+    [Benchmark()]
+    public bool FirstChar()
+    {
+        return _domainName.Length > 0 && _domainName[0] == '/';
+    }
+
+    [Benchmark()]
+    public bool Span()
+    {
+        return _domainName.AsSpan().StartsWith("/".AsSpan(),StringComparison.Ordinal);
+    }
+
+    /*
+       | Method    | Mean        | Error      | StdDev    | Allocated |
+       |---------- |------------:|-----------:|----------:|----------:|
+       | Original  | 255.2239 ns | 10.9432 ns | 0.5998 ns |         - |
+       | Ordinal   |   0.1784 ns |  0.3070 ns | 0.0168 ns |         - |
+       | Invariant |   4.1270 ns |  0.4990 ns | 0.0274 ns |         - |
+       | FirstChar |   0.0127 ns |  0.0098 ns | 0.0005 ns |         - |
+       | Span      |   0.8000 ns |  0.4526 ns | 0.0248 ns |         - |
+     */
+
+}