// SliceShrinker creates a slice shrinker from a shrinker for the elements of the slice.
// The length of the slice will be shrinked as well
func SliceShrinker(elementShrinker gopter.Shrinker) gopter.Shrinker {
return func(v interface{}) gopter.Shrink {
rv := reflect.ValueOf(v)
if rv.Kind() != reflect.Slice {
panic(fmt.Sprintf("%#v is not a slice", v))
}
sliceShrink := &sliceShrink{
original: rv,
offset: 0,
length: rv.Len(),
chunkLength: rv.Len() >> 1,
}
shrinks := make([]gopter.Shrink, 0, rv.Len()+1)
shrinks = append(shrinks, sliceShrink.Next)
for i := 0; i < rv.Len(); i++ {
sliceShrinkOne := &sliceShrinkOne{
original: rv,
index: i,
elementShrink: elementShrinker(rv.Index(i).Interface()),
}
shrinks = append(shrinks, sliceShrinkOne.Next)
}
return gopter.ConcatShrinks(shrinks...)
}
}
// PtrShrinker convert a value shrinker to a pointer to value shrinker
func PtrShrinker(elementShrinker gopter.Shrinker) gopter.Shrinker {
return func(v interface{}) gopter.Shrink {
if v == nil {
return gopter.NoShrink
}
rt := reflect.TypeOf(v)
elementShink := elementShrinker(reflect.ValueOf(v).Elem().Interface())
nilShrink := &nilShrink{}
return gopter.ConcatShrinks(
nilShrink.Next,
elementShink.Map(func(elem interface{}) interface{} {
slice := reflect.MakeSlice(reflect.SliceOf(rt.Elem()), 0, 1)
slice = reflect.Append(slice, reflect.ValueOf(elem))
return slice.Index(0).Addr().Interface()
}),
)
}
}