AutoMappingOverrideAlteration.cs

#if USE_NULLABLE
#nullable enable
#endif
using System.Linq;
using System.Reflection;

namespace FluentNHibernate.Automapping.Alterations;

/// <summary>
/// Built-in alteration for altering an AutoPersistenceModel with instance of IAutoMappingOverride&lt;T&gt;.
/// </summary>
/// <param name="overrideAssembly">Assembly to load overrides from.</param>
public class AutoMappingOverrideAlteration(Assembly overrideAssembly) : IAutoMappingAlteration
{
    /// <summary>
    /// Alter the model
    /// </summary>
    /// <remarks>
    /// Finds all types in the assembly (passed in the constructor) that implement IAutoMappingOverride&lt;T&gt;, then
    /// creates an AutoMapping&lt;T&gt; and applies the override to it.
    /// </remarks>
    /// <param name="model">AutoPersistenceModel instance to alter</param>
    public void Alter(AutoPersistenceModel model)
    {
        // find all types deriving from IAutoMappingOverride<T>
        var types = from type in overrideAssembly.GetExportedTypes()
            where !type.IsAbstract
            let entity = (from interfaceType in type.GetInterfaces()
                where interfaceType.IsGenericType && interfaceType.GetGenericTypeDefinition() == typeof(IAutoMappingOverride<>)
                select interfaceType.GetGenericArguments()[0]).FirstOrDefault()
            where entity is not null
            select type;

        foreach (var type in types)
        {
            model.Override(type);
        }
    }
}