Reduce allocations in Microsoft.Extensions.Configuration (#88211)

Co-authored-by: Günther Foidl <gue@korporal.at>
dotnet · Jun 30, 2023 · 7b13ea8 · 7b13ea8
1 parent e7e9925
commit 7b13ea8
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Showing 7 changed files with 32 additions and 30 deletions.
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Abstractions/src/ConfigurationPath.cs b/src/libraries/Microsoft.Extensions.Configuration.Abstractions/src/ConfigurationPath.cs
@@ -54,8 +54,8 @@ public static string Combine(IEnumerable<string> pathSegments)
                 return path;
             }
 
-            int lastDelimiterIndex = path.LastIndexOf(KeyDelimiter, StringComparison.OrdinalIgnoreCase);
-            return lastDelimiterIndex == -1 ? path : path.Substring(lastDelimiterIndex + 1);
+            int lastDelimiterIndex = path.LastIndexOf(':');
+            return lastDelimiterIndex < 0 ? path : path.Substring(lastDelimiterIndex + 1);
         }
 
         /// <summary>
@@ -70,8 +70,8 @@ public static string Combine(IEnumerable<string> pathSegments)
                 return null;
             }
 
-            int lastDelimiterIndex = path.LastIndexOf(KeyDelimiter, StringComparison.OrdinalIgnoreCase);
-            return lastDelimiterIndex == -1 ? null : path.Substring(0, lastDelimiterIndex);
+            int lastDelimiterIndex = path.LastIndexOf(':');
+            return lastDelimiterIndex < 0 ? null : path.Substring(0, lastDelimiterIndex);
         }
     }
 }
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Binder/src/ConfigurationBinder.cs b/src/libraries/Microsoft.Extensions.Configuration.Binder/src/ConfigurationBinder.cs
@@ -35,7 +35,7 @@ public static class ConfigurationBinder
         [RequiresDynamicCode(DynamicCodeWarningMessage)]
         [RequiresUnreferencedCode(TrimmingWarningMessage)]
         public static T? Get<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] T>(this IConfiguration configuration)
-            => configuration.Get<T>(_ => { });
+            => configuration.Get<T>(null);
 
         /// <summary>
         /// Attempts to bind the configuration instance to a new instance of type T.
@@ -71,7 +71,7 @@ public static class ConfigurationBinder
         [RequiresDynamicCode(DynamicCodeWarningMessage)]
         [RequiresUnreferencedCode(TrimmingWarningMessage)]
         public static object? Get(this IConfiguration configuration, Type type)
-            => configuration.Get(type, _ => { });
+            => configuration.Get(type, null);
 
         /// <summary>
         /// Attempts to bind the configuration instance to a new instance of type T.
@@ -118,7 +118,7 @@ public static void Bind(this IConfiguration configuration, string key, object? i
         [RequiresDynamicCode(DynamicCodeWarningMessage)]
         [RequiresUnreferencedCode(InstanceGetTypeTrimmingWarningMessage)]
         public static void Bind(this IConfiguration configuration, object? instance)
-            => configuration.Bind(instance, _ => { });
+            => configuration.Bind(instance, null);
 
         /// <summary>
         /// Attempts to bind the given object instance to configuration values by matching property names against configuration keys recursively.
@@ -220,13 +220,16 @@ private static void BindProperties(object instance, IConfiguration configuration
                 HashSet<string> propertyNames = new(modelProperties.Select(mp => mp.Name),
                     StringComparer.OrdinalIgnoreCase);
 
-                IEnumerable<IConfigurationSection> configurationSections = configuration.GetChildren();
-                List<string> missingPropertyNames = configurationSections
-                    .Where(cs => !propertyNames.Contains(cs.Key))
-                    .Select(mp => $"'{mp.Key}'")
-                    .ToList();
+                List<string>? missingPropertyNames = null;
+                foreach (IConfigurationSection cs in configuration.GetChildren())
+                {
+                    if (!propertyNames.Contains(cs.Key))
+                    {
+                        (missingPropertyNames ??= new()).Add($"'{cs.Key}'");
+                    }
+                }
 
-                if (missingPropertyNames.Count > 0)
+                if (missingPropertyNames != null)
                 {
                     throw new InvalidOperationException(SR.Format(SR.Error_MissingConfig,
                         nameof(options.ErrorOnUnknownConfiguration), nameof(BinderOptions), instance.GetType(),
@@ -381,7 +384,7 @@ private static void BindInstance(
                             (interfaceGenericType == typeof(ICollection<>) || interfaceGenericType == typeof(IList<>)))
                         {
                             // For ICollection<T> and IList<T> we bind them to mutable List<T> type.
-                            Type genericType = typeof(List<>).MakeGenericType(type.GenericTypeArguments[0]);
+                            Type genericType = typeof(List<>).MakeGenericType(type.GenericTypeArguments);
                             bindingPoint.SetValue(Activator.CreateInstance(genericType));
                         }
                         else

diff --git a/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationBuilder.cs b/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationBuilder.cs
@@ -11,10 +11,12 @@ namespace Microsoft.Extensions.Configuration
     /// </summary>
     public class ConfigurationBuilder : IConfigurationBuilder
     {
+        private readonly List<IConfigurationSource> _sources = new();
+
         /// <summary>
         /// Returns the sources used to obtain configuration values.
         /// </summary>
-        public IList<IConfigurationSource> Sources { get; } = new List<IConfigurationSource>();
+        public IList<IConfigurationSource> Sources => _sources;
 
         /// <summary>
         /// Gets a key/value collection that can be used to share data between the <see cref="IConfigurationBuilder"/>
@@ -31,7 +33,7 @@ public IConfigurationBuilder Add(IConfigurationSource source)
         {
             ThrowHelper.ThrowIfNull(source);
 
-            Sources.Add(source);
+            _sources.Add(source);
             return this;
         }
 
@@ -43,7 +45,7 @@ public IConfigurationBuilder Add(IConfigurationSource source)
         public IConfigurationRoot Build()
         {
             var providers = new List<IConfigurationProvider>();
-            foreach (IConfigurationSource source in Sources)
+            foreach (IConfigurationSource source in _sources)
             {
                 IConfigurationProvider provider = source.Build(this);
                 providers.Add(provider);

diff --git a/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationManager.cs b/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationManager.cs
@@ -229,10 +229,7 @@ public void CopyTo(IConfigurationSource[] array, int arrayIndex)
                 _sources.CopyTo(array, arrayIndex);
             }
 
-            public IEnumerator<IConfigurationSource> GetEnumerator()
-            {
-                return _sources.GetEnumerator();
-            }
+            public List<IConfigurationSource>.Enumerator GetEnumerator() => _sources.GetEnumerator();
 
             public int IndexOf(IConfigurationSource source)
             {
@@ -258,10 +255,9 @@ public void RemoveAt(int index)
                 _config.ReloadSources();
             }
 
-            IEnumerator IEnumerable.GetEnumerator()
-            {
-                return GetEnumerator();
-            }
+            IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+            IEnumerator<IConfigurationSource> IEnumerable<IConfigurationSource>.GetEnumerator() => GetEnumerator();
         }
 
         private sealed class ConfigurationBuilderProperties : IDictionary<string, object>

diff --git a/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationProvider.cs b/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationProvider.cs
@@ -95,7 +95,8 @@ public virtual IEnumerable<string> GetChildKeys(
 
         private static string Segment(string key, int prefixLength)
         {
-            int indexOf = key.IndexOf(ConfigurationPath.KeyDelimiter, prefixLength, StringComparison.OrdinalIgnoreCase);
+            Debug.Assert(ConfigurationPath.KeyDelimiter == ":");
+            int indexOf = key.IndexOf(':', prefixLength);
             return indexOf < 0 ? key.Substring(prefixLength) : key.Substring(prefixLength, indexOf - prefixLength);
         }
 

diff --git a/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationSection.cs b/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationSection.cs
@@ -69,11 +69,11 @@ public string? this[string key]
         {
             get
             {
-                return _root[ConfigurationPath.Combine(Path, key)];
+                return _root[Path + ConfigurationPath.KeyDelimiter + key];
             }
             set
             {
-                _root[ConfigurationPath.Combine(Path, key)] = value;
+                _root[Path + ConfigurationPath.KeyDelimiter + key] = value;
             }
         }
 
@@ -86,7 +86,7 @@ public string? this[string key]
         ///     This method will never return <c>null</c>. If no matching sub-section is found with the specified key,
         ///     an empty <see cref="IConfigurationSection"/> will be returned.
         /// </remarks>
-        public IConfigurationSection GetSection(string key) => _root.GetSection(ConfigurationPath.Combine(Path, key));
+        public IConfigurationSection GetSection(string key) => _root.GetSection(Path + ConfigurationPath.KeyDelimiter + key);
 
         /// <summary>
         /// Gets the immediate descendant configuration sub-sections.

diff --git a/src/libraries/Microsoft.Extensions.Configuration/src/InternalConfigurationRootExtensions.cs b/src/libraries/Microsoft.Extensions.Configuration/src/InternalConfigurationRootExtensions.cs
@@ -27,7 +27,7 @@ internal static IEnumerable<IConfigurationSection> GetChildrenImplementation(thi
                 .Aggregate(Enumerable.Empty<string>(),
                     (seed, source) => source.GetChildKeys(seed, path))
                 .Distinct(StringComparer.OrdinalIgnoreCase)
-                .Select(key => root.GetSection(path == null ? key : ConfigurationPath.Combine(path, key)));
+                .Select(key => root.GetSection(path == null ? key : path + ConfigurationPath.KeyDelimiter + key));
 
             if (reference is null)
             {