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

pentp · gfoidl · web-flow · commit 7b13ea8f0ebe · 2023-06-30T09:39:46.000-07:00
Co-authored-by: Günther Foidl &lt;gue@korporal.at&gt;
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)
             {

Original file line number	Diff line number	Diff line change
`@@ -54,8 +54,8 @@ public static string Combine(IEnumerable<string> pathSegments)`
`54`	`54`	`return path;`
`55`	`55`	`}`
`56`	`56`
`57`		`- int lastDelimiterIndex = path.LastIndexOf(KeyDelimiter, StringComparison.OrdinalIgnoreCase);`
`58`		`- return lastDelimiterIndex == -1 ? path : path.Substring(lastDelimiterIndex + 1);`
	`57`	`+ int lastDelimiterIndex = path.LastIndexOf(':');`
	`58`	`+ return lastDelimiterIndex < 0 ? path : path.Substring(lastDelimiterIndex + 1);`
`59`	`59`	`}`
`60`	`60`
`61`	`61`	`/// <summary>`
`@@ -70,8 +70,8 @@ public static string Combine(IEnumerable<string> pathSegments)`
`70`	`70`	`return null;`
`71`	`71`	`}`
`72`	`72`
`73`		`- int lastDelimiterIndex = path.LastIndexOf(KeyDelimiter, StringComparison.OrdinalIgnoreCase);`
`74`		`- return lastDelimiterIndex == -1 ? null : path.Substring(0, lastDelimiterIndex);`
	`73`	`+ int lastDelimiterIndex = path.LastIndexOf(':');`
	`74`	`+ return lastDelimiterIndex < 0 ? null : path.Substring(0, lastDelimiterIndex);`
`75`	`75`	`}`
`76`	`76`	`}`
`77`	`77`	`}`
Original file line number	Diff line number	Diff line change
`@@ -11,10 +11,12 @@ namespace Microsoft.Extensions.Configuration`
`11`	`11`	`/// </summary>`
`12`	`12`	`public class ConfigurationBuilder : IConfigurationBuilder`
`13`	`13`	`{`
	`14`	`+ private readonly List<IConfigurationSource> _sources = new();`
	`15`	`+`
`14`	`16`	`/// <summary>`
`15`	`17`	`/// Returns the sources used to obtain configuration values.`
`16`	`18`	`/// </summary>`
`17`		`- public IList<IConfigurationSource> Sources { get; } = new List<IConfigurationSource>();`
	`19`	`+ public IList<IConfigurationSource> Sources => _sources;`
`18`	`20`
`19`	`21`	`/// <summary>`
`20`	`22`	`/// 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)`
`31`	`33`	`{`
`32`	`34`	`ThrowHelper.ThrowIfNull(source);`
`33`	`35`
`34`		`- Sources.Add(source);`
	`36`	`+ _sources.Add(source);`
`35`	`37`	`return this;`
`36`	`38`	`}`
`37`	`39`
`@@ -43,7 +45,7 @@ public IConfigurationBuilder Add(IConfigurationSource source)`
`43`	`45`	`public IConfigurationRoot Build()`
`44`	`46`	`{`
`45`	`47`	`var providers = new List<IConfigurationProvider>();`
`46`		`- foreach (IConfigurationSource source in Sources)`
	`48`	`+ foreach (IConfigurationSource source in _sources)`
`47`	`49`	`{`
`48`	`50`	`IConfigurationProvider provider = source.Build(this);`
`49`	`51`	`providers.Add(provider);`
Original file line number	Diff line number	Diff line change
`@@ -229,10 +229,7 @@ public void CopyTo(IConfigurationSource[] array, int arrayIndex)`
`229`	`229`	`_sources.CopyTo(array, arrayIndex);`
`230`	`230`	`}`
`231`	`231`
`232`		`- public IEnumerator<IConfigurationSource> GetEnumerator()`
`233`		`- {`
`234`		`- return _sources.GetEnumerator();`
`235`		`- }`
	`232`	`+ public List<IConfigurationSource>.Enumerator GetEnumerator() => _sources.GetEnumerator();`
`236`	`233`
`237`	`234`	`public int IndexOf(IConfigurationSource source)`
`238`	`235`	`{`
`@@ -258,10 +255,9 @@ public void RemoveAt(int index)`
`258`	`255`	`_config.ReloadSources();`
`259`	`256`	`}`
`260`	`257`
`261`		`- IEnumerator IEnumerable.GetEnumerator()`
`262`		`- {`
`263`		`- return GetEnumerator();`
`264`		`- }`
	`258`	`+ IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();`
	`259`	`+`
	`260`	`+ IEnumerator<IConfigurationSource> IEnumerable<IConfigurationSource>.GetEnumerator() => GetEnumerator();`
`265`	`261`	`}`
`266`	`262`
`267`	`263`	`private sealed class ConfigurationBuilderProperties : IDictionary<string, object>`
Original file line number	Diff line number	Diff line change
`@@ -95,7 +95,8 @@ public virtual IEnumerable<string> GetChildKeys(`
`95`	`95`
`96`	`96`	`private static string Segment(string key, int prefixLength)`
`97`	`97`	`{`
`98`		`- int indexOf = key.IndexOf(ConfigurationPath.KeyDelimiter, prefixLength, StringComparison.OrdinalIgnoreCase);`
	`98`	`+ Debug.Assert(ConfigurationPath.KeyDelimiter == ":");`
	`99`	`+ int indexOf = key.IndexOf(':', prefixLength);`
`99`	`100`	`return indexOf < 0 ? key.Substring(prefixLength) : key.Substring(prefixLength, indexOf - prefixLength);`
`100`	`101`	`}`
`101`	`102`
Original file line number	Diff line number	Diff line change
`@@ -69,11 +69,11 @@ public string? this[string key]`
`69`	`69`	`{`
`70`	`70`	`get`
`71`	`71`	`{`
`72`		`- return _root[ConfigurationPath.Combine(Path, key)];`
	`72`	`+ return _root[Path + ConfigurationPath.KeyDelimiter + key];`
`73`	`73`	`}`
`74`	`74`	`set`
`75`	`75`	`{`
`76`		`- _root[ConfigurationPath.Combine(Path, key)] = value;`
	`76`	`+ _root[Path + ConfigurationPath.KeyDelimiter + key] = value;`
`77`	`77`	`}`
`78`	`78`	`}`
`79`	`79`
`@@ -86,7 +86,7 @@ public string? this[string key]`
`86`	`86`	`/// This method will never return <c>null</c>. If no matching sub-section is found with the specified key,`
`87`	`87`	`/// an empty <see cref="IConfigurationSection"/> will be returned.`
`88`	`88`	`/// </remarks>`
`89`		`- public IConfigurationSection GetSection(string key) => _root.GetSection(ConfigurationPath.Combine(Path, key));`
	`89`	`+ public IConfigurationSection GetSection(string key) => _root.GetSection(Path + ConfigurationPath.KeyDelimiter + key);`
`90`	`90`
`91`	`91`	`/// <summary>`
`92`	`92`	`/// Gets the immediate descendant configuration sub-sections.`
Original file line number	Diff line number	Diff line change
`@@ -27,7 +27,7 @@ internal static IEnumerable<IConfigurationSection> GetChildrenImplementation(thi`
`27`	`27`	`.Aggregate(Enumerable.Empty<string>(),`
`28`	`28`	`(seed, source) => source.GetChildKeys(seed, path))`
`29`	`29`	`.Distinct(StringComparer.OrdinalIgnoreCase)`
`30`		`- .Select(key => root.GetSection(path == null ? key : ConfigurationPath.Combine(path, key)));`
	`30`	`+ .Select(key => root.GetSection(path == null ? key : path + ConfigurationPath.KeyDelimiter + key));`
`31`	`31`
`32`	`32`	`if (reference is null)`
`33`	`33`	`{`