chore: refactor collections support

src/Riok.Mapperly/Descriptors/Enumerables/CollectionInfo.cs

@@ -0,0 +1,40 @@
+using Microsoft.CodeAnalysis;
+using Riok.Mapperly.Helpers;
+
+namespace Riok.Mapperly.Descriptors.Enumerables;
+
+public record CollectionInfo(
+    CollectionType Type,
+    CollectionType ImplementedTypes,
+    ITypeSymbol EnumeratedType,
+    bool CountIsKnown,
+    bool HasImplicitCollectionAddMethod,
+    bool IsImmutableCollectionType
+)
+{
+    public (ITypeSymbol, ITypeSymbol)? GetDictionaryKeyValueTypes(MappingBuilderContext ctx, ITypeSymbol t)
+    {
+        if (t.ImplementsGeneric(ctx.Types.Get(typeof(IDictionary<,>)), out var dictionaryImpl))
+        {
+            return (dictionaryImpl.TypeArguments[0], dictionaryImpl.TypeArguments[1]);
+        }
+
+        if (t.ImplementsGeneric(ctx.Types.Get(typeof(IReadOnlyDictionary<,>)), out var readOnlyDictionaryImpl))
+        {
+            return (readOnlyDictionaryImpl.TypeArguments[0], readOnlyDictionaryImpl.TypeArguments[1]);
+        }
+
+        return null;
+    }
+
+    public (ITypeSymbol, ITypeSymbol)? GetEnumeratedKeyValueTypes(WellKnownTypes types)
+    {
+        if (
+            EnumeratedType is not INamedTypeSymbol namedEnumeratedType
+            || !SymbolEqualityComparer.Default.Equals(namedEnumeratedType.ConstructedFrom, types.Get(typeof(KeyValuePair<,>)))
+        )
+            return null;
+
+        return (namedEnumeratedType.TypeArguments[0], namedEnumeratedType.TypeArguments[1]);
+    }
+}

src/Riok.Mapperly/Descriptors/Enumerables/CollectionInfoBuilder.cs

@@ -0,0 +1,146 @@
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis;
+using Riok.Mapperly.Helpers;
+
+namespace Riok.Mapperly.Descriptors.Enumerables;
+
+public static class CollectionInfoBuilder
+{
+    private record CollectionTypeInfo(
+        CollectionType CollectionType,
+        Type? ReflectionType = null,
+        string? TypeFullName = null,
+        bool Immutable = false
+    )
+    {
+        public INamedTypeSymbol? GetTypeSymbol(WellKnownTypes types)
+        {
+            if (ReflectionType != null)
+                return types.Get(ReflectionType);
+
+            if (TypeFullName != null)
+                return types.TryGet(TypeFullName);
+
+            throw new InvalidOperationException("One type needs to be set for each collection type");
+        }
+    }
+
+    private static readonly CollectionTypeInfo _collectionTypeInfoArray = new(CollectionType.Array);
+
+    private static readonly IReadOnlyCollection<CollectionTypeInfo> _collectionTypeInfos = new[]
+    {
+        new CollectionTypeInfo(CollectionType.IEnumerable, typeof(IEnumerable<>)),
+        new CollectionTypeInfo(CollectionType.List, typeof(List<>)),
+        new CollectionTypeInfo(CollectionType.Stack, typeof(Stack<>)),
+        new CollectionTypeInfo(CollectionType.Queue, typeof(Queue<>)),
+        new CollectionTypeInfo(CollectionType.IReadOnlyCollection, typeof(IReadOnlyCollection<>)),
+        new CollectionTypeInfo(CollectionType.IList, typeof(IList<>)),
+        new CollectionTypeInfo(CollectionType.IReadOnlyList, typeof(IReadOnlyList<>)),
+        new CollectionTypeInfo(CollectionType.ICollection, typeof(ICollection<>)),
+        new CollectionTypeInfo(CollectionType.HashSet, typeof(HashSet<>)),
+        new CollectionTypeInfo(CollectionType.SortedSet, typeof(SortedSet<>)),
+        new CollectionTypeInfo(CollectionType.ISet, typeof(ISet<>)),
+        new CollectionTypeInfo(CollectionType.IReadOnlySet, TypeFullName: "System.Collections.Generic.IReadOnlySet`1"),
+        new CollectionTypeInfo(CollectionType.IDictionary, typeof(IDictionary<,>)),
+        new CollectionTypeInfo(CollectionType.IReadOnlyDictionary, typeof(IReadOnlyDictionary<,>)),
+        new CollectionTypeInfo(CollectionType.Dictionary, typeof(Dictionary<,>)),
+        new CollectionTypeInfo(CollectionType.ImmutableArray, typeof(ImmutableArray<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.ImmutableList, typeof(ImmutableList<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.IImmutableList, typeof(IImmutableList<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.ImmutableHashSet, typeof(ImmutableHashSet<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.IImmutableSet, typeof(IImmutableSet<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.ImmutableSortedSet, typeof(ImmutableSortedSet<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.ImmutableQueue, typeof(ImmutableQueue<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.IImmutableQueue, typeof(IImmutableQueue<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.IImmutableQueue, typeof(IImmutableQueue<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.ImmutableStack, typeof(ImmutableStack<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.IImmutableStack, typeof(IImmutableStack<>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.IImmutableDictionary, typeof(IImmutableDictionary<,>), Immutable: true),
+        new CollectionTypeInfo(CollectionType.ImmutableDictionary, typeof(ImmutableDictionary<,>), Immutable: true),
+    };
+
+    public static CollectionInfos? Build(WellKnownTypes wellKnownTypes, ITypeSymbol source, ITypeSymbol target)
+    {
+        if (Build(wellKnownTypes, source) is not { } sourceInfo)
+            return null;
+
+        if (Build(wellKnownTypes, target) is not { } targetInfo)
+            return null;
+
+        return new CollectionInfos(sourceInfo, targetInfo);
+    }
+
+    private static CollectionInfo? Build(WellKnownTypes wellKnownTypes, ITypeSymbol type)
+    {
+        var enumeratedType = GetEnumeratedType(wellKnownTypes, type);
+        if (enumeratedType == null)
+            return null;
+
+        var collectionTypeInfo = GetCollectionTypeInfo(wellKnownTypes, type);
+        return new CollectionInfo(
+            collectionTypeInfo?.CollectionType ?? CollectionType.None,
+            GetImplementedCollectionTypes(wellKnownTypes, type),
+            enumeratedType,
+            IsCountKnown(wellKnownTypes, type),
+            HasValidAddMethod(wellKnownTypes, type),
+            collectionTypeInfo?.Immutable == true
+        );
+    }
+
+    private static ITypeSymbol? GetEnumeratedType(WellKnownTypes types, ITypeSymbol type)
+    {
+        return type.ImplementsGeneric(types.Get(typeof(IEnumerable<>)), out var enumerableIntf) ? enumerableIntf.TypeArguments[0] : null;
+    }
+
+    private static bool HasValidAddMethod(WellKnownTypes types, ITypeSymbol t)
+    {
+        return t.HasImplicitGenericImplementation(types.Get(typeof(ICollection<>)), nameof(ICollection<object>.Add))
+            || t.HasImplicitGenericImplementation(types.Get(typeof(ISet<>)), nameof(ISet<object>.Add));
+    }
+
+    private static bool IsCountKnown(WellKnownTypes types, ITypeSymbol t)
+    {
+        var intType = types.Get<int>();
+        return t.GetAccessibleMappableMembers()
+            .Any(
+                x =>
+                    x.Name is nameof(ICollection<object>.Count) or nameof(Array.Length)
+                    && SymbolEqualityComparer.IncludeNullability.Equals(intType, x.Type)
+            );
+    }
+
+    private static CollectionTypeInfo? GetCollectionTypeInfo(WellKnownTypes types, ITypeSymbol type)
+    {
+        if (type.IsArrayType())
+            return _collectionTypeInfoArray;
+
+        foreach (var typeInfo in _collectionTypeInfos)
+        {
+            if (typeInfo.GetTypeSymbol(types) is not { } typeSymbol)
+                continue;
+
+            if (SymbolEqualityComparer.Default.Equals(type.OriginalDefinition, typeSymbol))
+                return typeInfo;
+        }
+
+        return null;
+    }
+
+    private static CollectionType GetImplementedCollectionTypes(WellKnownTypes types, ITypeSymbol type)
+    {
+        var implementedCollectionTypes = type.IsArrayType() ? CollectionType.Array : CollectionType.None;
+
+        foreach (var typeInfo in _collectionTypeInfos)
+        {
+            if (typeInfo.GetTypeSymbol(types) is not { } typeSymbol)
+                continue;
+
+            if (type.ImplementsGeneric(typeSymbol, out _))
+            {
+                implementedCollectionTypes |= typeInfo.CollectionType;
+            }
+        }
+
+        return implementedCollectionTypes;
+    }
+}

src/Riok.Mapperly/Descriptors/Enumerables/CollectionInfos.cs

@@ -0,0 +1,3 @@
+namespace Riok.Mapperly.Descriptors.Enumerables;
+
+public record CollectionInfos(CollectionInfo Source, CollectionInfo Target);

src/Riok.Mapperly/Descriptors/Enumerables/CollectionType.cs

@@ -0,0 +1,43 @@
+namespace Riok.Mapperly.Descriptors.Enumerables;
+
+[Flags]
+public enum CollectionType
+{
+    None = 0,
+    Array = 1 << 0,
+    IEnumerable = 1 << 1,
+
+    // collections
+    List = 1 << 2,
+    Stack = 1 << 3,
+    Queue = 1 << 4,
+    IReadOnlyCollection = 1 << 5,
+    IList = 1 << 6,
+    IReadOnlyList = 1 << 7,
+    ICollection = 1 << 8,
+
+    // sets
+    HashSet = 1 << 9,
+    SortedSet = 1 << 10,
+    IReadOnlySet = 1 << 11,
+    ISet = 1 << 12,
+
+    // dictionaries
+    IDictionary = 1 << 13,
+    IReadOnlyDictionary = 1 << 14,
+    Dictionary = 1 << 15,
+
+    // immutable
+    ImmutableArray = 1 << 16,
+    ImmutableList = 1 << 17,
+    IImmutableList = 1 << 18,
+    ImmutableHashSet = 1 << 19,
+    IImmutableSet = 1 << 20,
+    ImmutableSortedSet = 1 << 21,
+    ImmutableQueue = 1 << 22,
+    IImmutableQueue = 1 << 23,
+    ImmutableStack = 1 << 24,
+    IImmutableStack = 1 << 25,
+    ImmutableDictionary = 1 << 26,
+    IImmutableDictionary = 1 << 27,
+}

src/Riok.Mapperly/Descriptors/Enumerables/EnsureCapacity/EnsureCapacityBuilder.cs

@@ -5,7 +5,7 @@
 namespace Riok.Mapperly.Descriptors.Enumerables.EnsureCapacity;
 
 /// <summary>
-/// Generates an <see cref="EnsureCapacity?"/> of types <see cref="EnsureCapacityNonEnumerated"/> or <see cref="EnsureCapacityMember"/> depending on type information.
+/// Generates an <see cref="EnsureCapacity"/> of types <see cref="EnsureCapacityNonEnumerated"/> or <see cref="EnsureCapacityMember"/> depending on type information.
 /// </summary>
 public static class EnsureCapacityBuilder
 {
@@ -14,28 +14,27 @@ public static class EnsureCapacityBuilder
     private const string LengthPropertyName = nameof(Array.Length);
     private const string TryGetNonEnumeratedCountMethodName = "TryGetNonEnumeratedCount";
 
-    public static EnsureCapacity? TryBuildEnsureCapacity(ITypeSymbol sourceType, ITypeSymbol targetType, WellKnownTypes types)
+    public static EnsureCapacity? TryBuildEnsureCapacity(MappingBuilderContext ctx)
     {
-        var capacityMethod = targetType
+        var capacityMethod = ctx.Target
             .GetAllMethods(EnsureCapacityName)
-            .OfType<IMethodSymbol>()
             .FirstOrDefault(x => x.Parameters.Length == 1 && x.Parameters[0].Type.SpecialType == SpecialType.System_Int32 && !x.IsStatic);
 
         // if EnsureCapacity is not available then return null
         if (capacityMethod == null)
             return null;
 
         // if target does not have a count then return null
-        if (!TryGetNonEnumeratedCount(targetType, types, out var targetSizeProperty))
+        if (!TryGetNonEnumeratedCount(ctx.Target, ctx.Types, out var targetSizeProperty))
             return null;
 
         // if target and source count are known then create a simple EnsureCapacity statement
-        if (TryGetNonEnumeratedCount(sourceType, types, out var sourceSizeProperty))
+        if (TryGetNonEnumeratedCount(ctx.Source, ctx.Types, out var sourceSizeProperty))
             return new EnsureCapacityMember(targetSizeProperty, sourceSizeProperty);
 
-        sourceType.ImplementsGeneric(types.Get(typeof(IEnumerable<>)), out var iEnumerable);
+        ctx.Source.ImplementsGeneric(ctx.Types.Get(typeof(IEnumerable<>)), out var iEnumerable);
 
-        var nonEnumeratedCountMethod = types
+        var nonEnumeratedCountMethod = ctx.Types
             .Get(typeof(Enumerable))
             .GetMembers(TryGetNonEnumeratedCountMethodName)
             .OfType<IMethodSymbol>()
@@ -47,7 +46,7 @@ public static class EnsureCapacityBuilder
         if (nonEnumeratedCountMethod == null)
             return null;
 
-        // if source does not have a count use GetNonEnumeratedCount, calling EnusureCapacity if count is available
+        // if source does not have a count use GetNonEnumeratedCount, calling EnsureCapacity if count is available
         var typedNonEnumeratedCount = nonEnumeratedCountMethod.Construct(iEnumerable!.TypeArguments.ToArray());
         return new EnsureCapacityNonEnumerated(targetSizeProperty, typedNonEnumeratedCount);
     }

src/Riok.Mapperly/Descriptors/MappingBuilderContext.cs

@@ -1,6 +1,7 @@
 using System.Diagnostics;
 using Microsoft.CodeAnalysis;
 using Riok.Mapperly.Configuration;
+using Riok.Mapperly.Descriptors.Enumerables;
 using Riok.Mapperly.Descriptors.Mappings;
 using Riok.Mapperly.Descriptors.Mappings.ExistingTarget;
 using Riok.Mapperly.Descriptors.Mappings.UserMappings;
@@ -14,6 +15,7 @@ namespace Riok.Mapperly.Descriptors;
 public class MappingBuilderContext : SimpleMappingBuilderContext
 {
     private readonly IMethodSymbol? _userSymbol;
+    private CollectionInfos? _collectionInfos;
 
     public MappingBuilderContext(
         SimpleMappingBuilderContext parentCtx,
@@ -40,6 +42,8 @@ protected MappingBuilderContext(MappingBuilderContext ctx, IMethodSymbol? userSy
 
     public ITypeSymbol Target { get; }
 
+    public CollectionInfos? CollectionInfos => _collectionInfos ??= CollectionInfoBuilder.Build(Types, Source, Target);
+
     /// <summary>
     /// Whether the current mapping code is generated for a <see cref="System.Linq.Expressions.Expression"/>.
     /// </summary>