MemberRelationshipService.cs

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using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
 
namespace System.ComponentModel.Design.Serialization;
 
public abstract class MemberRelationshipService
{
    private struct RelationshipEntry
    {
        internal WeakReference _owner;
 
        internal MemberDescriptor _member;
 
        private readonly int _hashCode;
 
        internal RelationshipEntry(MemberRelationship rel)
        {
            _owner = new WeakReference(rel.Owner);
            _member = rel.Member;
            _hashCode = ((rel.Owner != null) ? rel.Owner.GetHashCode() : 0);
        }
 
        public override bool Equals([NotNullWhen(true)] object o)
        {
            return this == (RelationshipEntry)o;
        }
 
        public static bool operator ==(RelationshipEntry re1, RelationshipEntry re2)
        {
            object obj = (re1._owner.IsAlive ? re1._owner.Target : null);
            object obj2 = (re2._owner.IsAlive ? re2._owner.Target : null);
            if (obj == obj2)
            {
                return re1._member.Equals(re2._member);
            }
            return false;
        }
 
        public override int GetHashCode()
        {
            return _hashCode;
        }
    }
 
    private readonly Dictionary<RelationshipEntry, RelationshipEntry> _relationships = new Dictionary<RelationshipEntry, RelationshipEntry>();
 
    public MemberRelationship this[MemberRelationship source]
    {
        get
        {
            if (source.Owner == null)
            {
                throw new ArgumentException(System.SR.Format(System.SR.InvalidNullArgument, "source.Owner"), "source");
            }
            return GetRelationship(source);
        }
        set
        {
            if (source.Owner == null)
            {
                throw new ArgumentException(System.SR.Format(System.SR.InvalidNullArgument, "source.Owner"), "source");
            }
            SetRelationship(source, value);
        }
    }
 
    public MemberRelationship this[object sourceOwner, MemberDescriptor sourceMember]
    {
        get
        {
            if (sourceOwner == null)
            {
                throw new ArgumentNullException("sourceOwner");
            }
            if (sourceMember == null)
            {
                throw new ArgumentNullException("sourceMember");
            }
            return GetRelationship(new MemberRelationship(sourceOwner, sourceMember));
        }
        set
        {
            if (sourceOwner == null)
            {
                throw new ArgumentNullException("sourceOwner");
            }
            if (sourceMember == null)
            {
                throw new ArgumentNullException("sourceMember");
            }
            SetRelationship(new MemberRelationship(sourceOwner, sourceMember), value);
        }
    }
 
    protected virtual MemberRelationship GetRelationship(MemberRelationship source)
    {
        if (_relationships.TryGetValue(new RelationshipEntry(source), out var value) && value._owner.IsAlive)
        {
            return new MemberRelationship(value._owner.Target, value._member);
        }
        return MemberRelationship.Empty;
    }
 
    protected virtual void SetRelationship(MemberRelationship source, MemberRelationship relationship)
    {
        if (!relationship.IsEmpty && !SupportsRelationship(source, relationship))
        {
            ThrowRelationshipNotSupported(source, relationship);
        }
        _relationships[new RelationshipEntry(source)] = new RelationshipEntry(relationship);
    }
 
    [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "GetComponentName is only used to create a nice exception message, and has a fallback when null is returned.")]
    private static void ThrowRelationshipNotSupported(MemberRelationship source, MemberRelationship relationship)
    {
        string text = TypeDescriptor.GetComponentName(source.Owner);
        string text2 = TypeDescriptor.GetComponentName(relationship.Owner);
        if (text == null)
        {
            text = source.Owner.ToString();
        }
        if (text2 == null)
        {
            text2 = relationship.Owner.ToString();
        }
        throw new ArgumentException(System.SR.Format(System.SR.MemberRelationshipService_RelationshipNotSupported, text, source.Member.Name, text2, relationship.Member.Name));
    }
 
    public abstract bool SupportsRelationship(MemberRelationship source, MemberRelationship relationship);
}