Review usage of string.Substring (part 1)

Reduced allocations by replacing string.Substring with ReadOnlySpan<char>.Slice

3 files changed, 18 insertions, 9 deletions

diff --git a/Emby.Server.Implementations/Services/ServiceExec.cs b/Emby.Server.Implementations/Services/ServiceExec.cs
index cbc4b754d..947a5cbf8 100644
--- a/Emby.Server.Implementations/Services/ServiceExec.cs
+++ b/Emby.Server.Implementations/Services/ServiceExec.cs
@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
@@ -105,7 +106,12 @@ namespace Emby.Server.Implementations.Services
             }
 
             var expectedMethodName = actionName.Substring(0, 1) + actionName.Substring(1).ToLowerInvariant();
-            throw new NotImplementedException(string.Format("Could not find method named {1}({0}) or Any({0}) on Service {2}", requestDto.GetType().GetMethodName(), expectedMethodName, serviceType.GetMethodName()));
+            throw new NotImplementedException(
+                string.Format(
+                    CultureInfo.InvariantCulture,
+                    "Could not find method named {1}({0}) or Any({0}) on Service {2}",
+                    requestDto.GetType().GetMethodName(),
+                    expectedMethodName, serviceType.GetMethodName()));
         }
 
         private static async Task<object> GetTaskResult(Task task)
diff --git a/Emby.Server.Implementations/Services/ServiceHandler.cs b/Emby.Server.Implementations/Services/ServiceHandler.cs
index a42f88ea0..e63a80cee 100644
--- a/Emby.Server.Implementations/Services/ServiceHandler.cs
+++ b/Emby.Server.Implementations/Services/ServiceHandler.cs
@@ -44,7 +44,7 @@ namespace Emby.Server.Implementations.Services
             var pos = pathInfo.LastIndexOf('.');
             if (pos != -1)
             {
-                var format = pathInfo.Substring(pos + 1);
+                var format = pathInfo.AsSpan().Slice(pos + 1);
                 contentType = GetFormatContentType(format);
                 if (contentType != null)
                 {
@@ -55,15 +55,18 @@ namespace Emby.Server.Implementations.Services
             return pathInfo;
         }
 
-        private static string GetFormatContentType(string format)
+        private static string GetFormatContentType(ReadOnlySpan<char> format)
         {
-            // built-in formats
-            switch (format)
+            if (format.Equals("json", StringComparison.Ordinal))
             {
-                case "json": return "application/json";
-                case "xml": return "application/xml";
-                default: return null;
+                return "application/json";
             }
+            else if (format.Equals("xml", StringComparison.Ordinal))
+            {
+                return "application/xml";
+            }
+
+            return null;
         }
 
         public async Task ProcessRequestAsync(HttpListenerHost httpHost, IRequest httpReq, HttpResponse httpRes, ILogger logger, CancellationToken cancellationToken)
diff --git a/Emby.Server.Implementations/Services/ServicePath.cs b/Emby.Server.Implementations/Services/ServicePath.cs
index 89538ae72..69c6844f8 100644
--- a/Emby.Server.Implementations/Services/ServicePath.cs
+++ b/Emby.Server.Implementations/Services/ServicePath.cs
@@ -156,7 +156,7 @@ namespace Emby.Server.Implementations.Services
             {
                 var component = components[i];
 
-                if (component.StartsWith(VariablePrefix))
+                if (component.StartsWith(VariablePrefix, StringComparison.Ordinal))
                 {
                     var variableName = component.Substring(1, component.Length - 2);
                     if (variableName[variableName.Length - 1] == WildCardChar)