allocate _runtimeTypeDetails lazily

Author: lbargaoanu

src/AutoMapper/ApiCompatBaseline.txt

@@ -93,6 +93,7 @@ TypeCannotChangeClassification : Type 'AutoMapper.Execution.TypeMapPlanBuilder'
 MembersMustExist : Member 'public System.Linq.Expressions.LambdaExpression AutoMapper.Execution.TypeMapPlanBuilder.CreateMapperLambda(System.Collections.Generic.HashSet<AutoMapper.TypeMap>)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public System.Linq.Expressions.ParameterExpression AutoMapper.Execution.TypeMapPlanBuilder.Source.get()' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public System.Collections.Generic.IEnumerator<TFeature> AutoMapper.Features.Features<TFeature>.GetEnumerator()' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'AutoMapper.Internal.ConcurrentDictionaryWrapper<TKey, TValue>' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public System.Reflection.ConstructorInfo System.Reflection.ConstructorInfo AutoMapper.Internal.ConstructorParameters.Constructor' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public System.Reflection.ParameterInfo[] System.Reflection.ParameterInfo[] AutoMapper.Internal.ConstructorParameters.Parameters' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public AutoMapper.Internal.TypePair AutoMapper.Internal.TypePair AutoMapper.Internal.MapRequest.RequestedTypes' does not exist in the implementation but it does exist in the contract.
@@ -119,4 +120,4 @@ MembersMustExist : Member 'public AutoMapper.Internal.TypePair AutoMapper.Intern
 MembersMustExist : Member 'public System.Linq.IQueryable<TDestination> AutoMapper.QueryableExtensions.Extensions.Map<TSource, TDestination>(System.Linq.IQueryable<TSource>, System.Linq.IQueryable<TDestination>, AutoMapper.IConfigurationProvider)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public System.Collections.Generic.IReadOnlyCollection<System.Reflection.MemberInfo> AutoMapper.QueryableExtensions.MemberVisitor.MemberPath.get()' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'AutoMapper.QueryableExtensions.Impl.MemberAccessQueryMapperVisitor' does not exist in the implementation but it does exist in the contract.
-Total Issues: 120
+Total Issues: 121

src/AutoMapper/Internal/LockingConcurrentDictionary.cs

@@ -1,22 +1,13 @@
 using System.Collections.Concurrent;
-
 namespace AutoMapper.Internal;
-
 public readonly struct LockingConcurrentDictionary<TKey, TValue>
 {
-    private readonly ConcurrentDictionaryWrapper<TKey, Lazy<TValue>> _dictionary;
-    public LockingConcurrentDictionary(Func<TKey, TValue> valueFactory, int capacity = 31) =>
-        _dictionary = new(key => new(() => valueFactory(key)), capacity);
-    public TValue GetOrAdd(in TKey key) => _dictionary.GetOrAdd(key).Value;
-}
-public readonly struct ConcurrentDictionaryWrapper<TKey, TValue>
-{
-    private readonly ConcurrentDictionary<TKey, TValue> _dictionary;
-    private readonly Func<TKey, TValue> _valueFactory;
-    public ConcurrentDictionaryWrapper(Func<TKey, TValue> valueFactory, int capacity = 31)
+    private readonly Func<TKey, Lazy<TValue>> _valueFactory;
+    private readonly ConcurrentDictionary<TKey, Lazy<TValue>> _dictionary;
+    public LockingConcurrentDictionary(Func<TKey, TValue> valueFactory, int capacity = 31)
     {
+        _valueFactory = key => new(()=>valueFactory(key));
         _dictionary = new(Environment.ProcessorCount, capacity);
-        _valueFactory = valueFactory;
     }
-    public TValue GetOrAdd(in TKey key) => _dictionary.GetOrAdd(key, _valueFactory);
+    public TValue GetOrAdd(in TKey key) => _dictionary.GetOrAdd(key, _valueFactory).Value;
 }

src/AutoMapper/ProfileMap.cs

@@ -1,4 +1,5 @@
 using AutoMapper.Configuration.Conventions;
+using System.Collections.Concurrent;
 namespace AutoMapper;
 [DebuggerDisplay("{Name}")]
 [EditorBrowsable(EditorBrowsableState.Never)]
@@ -8,7 +9,7 @@ public class ProfileMap
     private TypeMapConfiguration[] _typeMapConfigs;
     private Dictionary<TypePair, TypeMapConfiguration> _openTypeMapConfigs;
     private Dictionary<Type, TypeDetails> _typeDetails;
-    private ConcurrentDictionaryWrapper<Type, TypeDetails> _runtimeTypeDetails;
+    private ConcurrentDictionary<Type, TypeDetails> _runtimeTypeDetails;
     public ProfileMap(IProfileConfiguration profile, IGlobalConfigurationExpression configuration = null)
     {
         var globalProfile = (IProfileConfiguration)configuration;
@@ -74,7 +75,6 @@ internal void Clear()
     {
         _typeDetails = null;
         _typeMapConfigs = null;
-        _runtimeTypeDetails = new(TypeDetailsFactory, 2 * _openTypeMapConfigs.Count);
     }
     public bool AllowNullCollections { get; }
     public bool AllowNullDestinationValues { get; }
@@ -99,17 +99,20 @@ public TypeDetails CreateTypeDetails(Type type)
     {
         if (_typeDetails == null)
         {
-            return _runtimeTypeDetails.GetOrAdd(type);
+            if (_runtimeTypeDetails == null)
+            {
+                Interlocked.CompareExchange(ref _runtimeTypeDetails, new(Environment.ProcessorCount, 2 * _openTypeMapConfigs.Count), null);
+            }
+            return _runtimeTypeDetails.GetOrAdd(type, (type, profile) => new(type, profile), this);
         }
         if (_typeDetails.TryGetValue(type, out var typeDetails))
         {
             return typeDetails;
         }
-        typeDetails = TypeDetailsFactory(type);
+        typeDetails = new(type, this);
         _typeDetails.Add(type, typeDetails);
         return typeDetails;
     }
-    private TypeDetails TypeDetailsFactory(Type type) => new(type, this);
     public void Register(IGlobalConfiguration configuration)
     {
         foreach (var config in _typeMapConfigs)