type Applier interface {
	// Apply applies the content referred to by the given descriptor to
	// the provided mount. The method of applying is based on the
	// implementation and content descriptor. For example, in the common
	// case the descriptor is a file system difference in tar format,
	// that tar would be applied on top of the mounts.
	Apply(ctx context.Context, desc ocispec.Descriptor, mount []mount.Mount) (ocispec.Descriptor, error)
}

type Comparer interface {
	// Compare computes the difference between two mounts and returns a
	// descriptor for the computed diff. The options can provide
	// a ref which can be used to track the content creation of the diff.
	// The media type which is used to determine the format of the created
	// content can also be provided as an option.
	Compare(ctx context.Context, lower, upper []mount.Mount, opts ...Opt) (ocispec.Descriptor, error)
}

type Config struct {
	// MediaType is the type of diff to generate
	// Default depends on the differ,
	// i.e. application/vnd.oci.image.layer.v1.tar+gzip
	MediaType string

	// Reference is the content upload reference
	// Default will use a random reference string
	Reference string

	// Labels are the labels to apply to the generated content
	Labels map[string]string
}

type Opt func(*Config) error