sarulabs/statix

package resource

// Alteration is the interface defining structures that can take
// a resource and return a new modified one.
type Alteration interface {
    Alter(Resource) (Resource, error)
}

// AlteredResource is a Resource to which is applied a list of alterations.
type AlteredResource struct {
    Resource    Resource
    Alterations []Alteration
}

// NewAlteredResource creates a new AlteredResource.
func NewAlteredResource(r Resource, a ...Alteration) *AlteredResource {
    return &AlteredResource{
        Resource:    r,
        Alterations: a,
    }
}

// Dump returns the content of an AlteredResource.
func (ar *AlteredResource) Dump() ([]byte, error) {
    var err error
    r := ar.Resource
    for _, alteration := range ar.Alterations {
        r, err = alteration.Alter(r)
        if err != nil {
            return []byte{}, err
        }
    }
    return r.Dump()
}

// In returns a new AlteredResource that is the same as the structed on which
// the method is applied, but with the In method applied to its Resource attribute.
func (ar *AlteredResource) In(path string) Resource {
    return &AlteredResource{
        Resource:    ar.Resource.In(path),
        Alterations: ar.Alterations,
    }
}