public object Get(Type type, CacheInfo info)
{
info = info.WithType(Nullable.GetUnderlyingType(type) ?? type);
if (cache.TryGetValue(info, out var existing))
{
return(existing);
}
return(parentContainer?.Get(type, info));
}
/// <summary>
/// Caches an instance of a type as a type of <paramref name="type"/>. This instance will be returned each time you <see cref="Get(Type)"/>.
/// </summary>
/// <param name="type">The type to cache <paramref name="instance"/> as.</param>
/// <param name="info">Extra information to identify <paramref name="instance"/> in the cache.</param>
/// <param name="instance">The instance to cache. Must be or derive from <paramref name="type"/>.</param>
/// <param name="allowValueTypes">Whether value types are allowed to be cached.
/// This should only be used when it is guaranteed that the internal state of the type will remain consistent through retrieval.
/// (e.g. <see cref="CancellationToken"/> or reference types).</param>
internal void CacheAs(Type type, CacheInfo info, object instance, bool allowValueTypes)
{
if (instance == null)
{
if (allowValueTypes)
{
return;
}
throw new ArgumentNullException(nameof(instance));
}
info = info.WithType(Nullable.GetUnderlyingType(type) ?? type);
var instanceType = instance.GetType();
instanceType = Nullable.GetUnderlyingType(instanceType) ?? instanceType;
if (instanceType.IsValueType && !allowValueTypes)
{
throw new ArgumentException($"{instanceType.ReadableName()} must be a class to be cached as a dependency.", nameof(instance));
}
if (!info.Type.IsInstanceOfType(instance))
{
throw new ArgumentException($"{instanceType.ReadableName()} must be a subclass of {info.Type.ReadableName()}.", nameof(instance));
}
// We can theoretically make this work by adding a nested dependency container. That would be a pretty big change though.
// For now, let's throw an exception as this leads to unexpected behaviours (depends on ordering of processing of attributes vs CreateChildDependencies).
if (cache.TryGetValue(info, out _))
{
throw new TypeAlreadyCachedException(info);
}
cache[info] = instance;
}