package httperr

import "net/http"

// The HandlerFunc type is an adapter to allow the use of
// ordinary functions as HTTP handlers.  If f is a function
// with the appropriate signature, HandlerFunc(f) is a
// Handler object that calls f.
type HandlerFunc func(http.ResponseWriter, *http.Request) error

// ServeHTTP calls f(w, r).
func (f HandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if err := f(w, r); err != nil {
		if v := r.Context().Value(onErrorIndex); v != nil {
			v.(func(error))(err)
		} else {
			Write(w, r, err)
		}
	}
}