package convert
import (
"github.com/zclconf/go-cty/cty"
)
// conversion is an internal variant of Conversion that carries around
// a cty.Path to be used in error responses.
type conversion func(cty.Value, cty.Path) (cty.Value, error)
func getConversion(in cty.Type, out cty.Type, unsafe bool) conversion {
conv := getConversionKnown(in, out, unsafe)
if conv == nil {
return nil
}
// Wrap the conversion in some standard checks that we don't want to
// have to repeat in every conversion function.
return func(in cty.Value, path cty.Path) (cty.Value, error) {
if !in.IsKnown() {
return cty.UnknownVal(out), nil
}
if in.IsNull() {
// We'll pass through nulls, albeit type converted, and let
// the caller deal with whatever handling they want to do in
// case null values are considered valid in some applications.
return cty.NullVal(out), nil
}
return conv(in, path)
}
}
func getConversionKnown(in cty.Type, out cty.Type, unsafe bool) conversion {
switch {
case out == cty.DynamicPseudoType:
// Conversion *to* DynamicPseudoType means that the caller wishes
// to allow any type in this position, so we'll produce a do-nothing
// conversion that just passes through the value as-is.
return dynamicPassthrough
case unsafe && in == cty.DynamicPseudoType:
// Conversion *from* DynamicPseudoType means that we have a value
// whose type isn't yet known during type checking. For these we will
// assume that conversion will succeed and deal with any errors that
// result (which is why we can only do this when "unsafe" is set).
return dynamicFixup(out)
case in.IsPrimitiveType() && out.IsPrimitiveType():
conv := primitiveConversionsSafe[in][out]
if conv != nil {
return conv
}
if unsafe {
return primitiveConversionsUnsafe[in][out]
}
return nil
case out.IsListType() && (in.IsListType() || in.IsSetType()):
inEty := in.ElementType()
outEty := out.ElementType()
if inEty.Equals(outEty) {
// This indicates that we're converting from list to set with
// the same element type, so we don't need an element converter.
return conversionCollectionToList(outEty, nil)
}
convEty := getConversion(inEty, outEty, unsafe)
if convEty == nil {
return nil
}
return conversionCollectionToList(outEty, convEty)
case out.IsSetType() && (in.IsListType() || in.IsSetType()):
if in.IsListType() && !unsafe {
// Conversion from list to map is unsafe because it will lose
// information: the ordering will not be preserved, and any
// duplicate elements will be conflated.
return nil
}
inEty := in.ElementType()
outEty := out.ElementType()
convEty := getConversion(inEty, outEty, unsafe)
if inEty.Equals(outEty) {
// This indicates that we're converting from set to list with
// the same element type, so we don't need an element converter.
return conversionCollectionToSet(outEty, nil)
}
if convEty == nil {
return nil
}
return conversionCollectionToSet(outEty, convEty)
case out.IsListType() && in.IsTupleType():
outEty := out.ElementType()
return conversionTupleToList(in, outEty, unsafe)
case out.IsMapType() && in.IsObjectType():
outEty := out.ElementType()
return conversionObjectToMap(in, outEty, unsafe)
default:
return nil
}
}
// retConversion wraps a conversion (internal type) so it can be returned
// as a Conversion (public type).
func retConversion(conv conversion) Conversion {
if conv == nil {
return nil
}
return func(in cty.Value) (cty.Value, error) {
return conv(in, cty.Path(nil))
}
}
