Modify parsing functions and config structs to accept hcl changes

Signed-off-by: Patrick Van Stee <patrick@vanstee.me>

vendor/github.com/zclconf/go-cty/cty/gocty/out.go

@@ -0,0 +1,686 @@
+package gocty
+
+import (
+	"math"
+	"math/big"
+	"reflect"
+
+	"github.com/zclconf/go-cty/cty"
+)
+
+// FromCtyValue assigns a cty.Value to a reflect.Value, which must be a pointer,
+// using a fixed set of conversion rules.
+//
+// This function considers its audience to be the creator of the cty Value
+// given, and thus the error messages it generates are (unlike with ToCtyValue)
+// presented in cty terminology that is generally appropriate to return to
+// end-users in applications where cty data structures are built from
+// user-provided configuration. In particular this means that if incorrect
+// target types are provided by the calling application the resulting error
+// messages are likely to be confusing, since we assume that the given target
+// type is correct and the cty.Value is where the error lies.
+//
+// If an error is returned, the target data structure may have been partially
+// populated, but the degree to which this is true is an implementation
+// detail that the calling application should not rely on.
+//
+// The function will panic if given a non-pointer as the Go value target,
+// since that is considered to be a bug in the calling program.
+func FromCtyValue(val cty.Value, target interface{}) error {
+	tVal := reflect.ValueOf(target)
+	if tVal.Kind() != reflect.Ptr {
+		panic("target value is not a pointer")
+	}
+	if tVal.IsNil() {
+		panic("target value is nil pointer")
+	}
+
+	// 'path' starts off as empty but will grow for each level of recursive
+	// call we make, so by the time fromCtyValue returns it is likely to have
+	// unused capacity on the end of it, depending on how deeply-recursive
+	// the given cty.Value is.
+	path := make(cty.Path, 0)
+	return fromCtyValue(val, tVal, path)
+}
+
+func fromCtyValue(val cty.Value, target reflect.Value, path cty.Path) error {
+	ty := val.Type()
+
+	deepTarget := fromCtyPopulatePtr(target, false)
+
+	// If we're decoding into a cty.Value then we just pass through the
+	// value as-is, to enable partial decoding. This is the only situation
+	// where unknown values are permitted.
+	if deepTarget.Kind() == reflect.Struct && deepTarget.Type().AssignableTo(valueType) {
+		deepTarget.Set(reflect.ValueOf(val))
+		return nil
+	}
+
+	// Lists and maps can be nil without indirection, but everything else
+	// requires a pointer and we set it immediately to nil.
+	// We also make an exception for capsule types because we want to handle
+	// pointers specially for these.
+	// (fromCtyList and fromCtyMap must therefore deal with val.IsNull, while
+	// other types can assume no nulls after this point.)
+	if val.IsNull() && !val.Type().IsListType() && !val.Type().IsMapType() && !val.Type().IsCapsuleType() {
+		target = fromCtyPopulatePtr(target, true)
+		if target.Kind() != reflect.Ptr {
+			return path.NewErrorf("null value is not allowed")
+		}
+
+		target.Set(reflect.Zero(target.Type()))
+		return nil
+	}
+
+	target = deepTarget
+
+	if !val.IsKnown() {
+		return path.NewErrorf("value must be known")
+	}
+
+	switch ty {
+	case cty.Bool:
+		return fromCtyBool(val, target, path)
+	case cty.Number:
+		return fromCtyNumber(val, target, path)
+	case cty.String:
+		return fromCtyString(val, target, path)
+	}
+
+	switch {
+	case ty.IsListType():
+		return fromCtyList(val, target, path)
+	case ty.IsMapType():
+		return fromCtyMap(val, target, path)
+	case ty.IsSetType():
+		return fromCtySet(val, target, path)
+	case ty.IsObjectType():
+		return fromCtyObject(val, target, path)
+	case ty.IsTupleType():
+		return fromCtyTuple(val, target, path)
+	case ty.IsCapsuleType():
+		return fromCtyCapsule(val, target, path)
+	}
+
+	// We should never fall out here; reaching here indicates a bug in this
+	// function.
+	return path.NewErrorf("unsupported source type %#v", ty)
+}
+
+func fromCtyBool(val cty.Value, target reflect.Value, path cty.Path) error {
+	switch target.Kind() {
+
+	case reflect.Bool:
+		target.SetBool(val.True())
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyNumber(val cty.Value, target reflect.Value, path cty.Path) error {
+	bf := val.AsBigFloat()
+
+	switch target.Kind() {
+
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return fromCtyNumberInt(bf, target, path)
+
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return fromCtyNumberUInt(bf, target, path)
+
+	case reflect.Float32, reflect.Float64:
+		return fromCtyNumberFloat(bf, target, path)
+
+	case reflect.Struct:
+		return fromCtyNumberBig(bf, target, path)
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyNumberInt(bf *big.Float, target reflect.Value, path cty.Path) error {
+	// Doing this with switch rather than << arithmetic because << with
+	// result >32-bits is not portable to 32-bit systems.
+	var min int64
+	var max int64
+	switch target.Type().Bits() {
+	case 8:
+		min = math.MinInt8
+		max = math.MaxInt8
+	case 16:
+		min = math.MinInt16
+		max = math.MaxInt16
+	case 32:
+		min = math.MinInt32
+		max = math.MaxInt32
+	case 64:
+		min = math.MinInt64
+		max = math.MaxInt64
+	default:
+		panic("weird number of bits in target int")
+	}
+
+	iv, accuracy := bf.Int64()
+	if accuracy != big.Exact || iv < min || iv > max {
+		return path.NewErrorf("value must be a whole number, between %d and %d", min, max)
+	}
+
+	target.SetInt(iv)
+	return nil
+}
+
+func fromCtyNumberUInt(bf *big.Float, target reflect.Value, path cty.Path) error {
+	// Doing this with switch rather than << arithmetic because << with
+	// result >32-bits is not portable to 32-bit systems.
+	var max uint64
+	switch target.Type().Bits() {
+	case 8:
+		max = math.MaxUint8
+	case 16:
+		max = math.MaxUint16
+	case 32:
+		max = math.MaxUint32
+	case 64:
+		max = math.MaxUint64
+	default:
+		panic("weird number of bits in target uint")
+	}
+
+	iv, accuracy := bf.Uint64()
+	if accuracy != big.Exact || iv > max {
+		return path.NewErrorf("value must be a whole number, between 0 and %d inclusive", max)
+	}
+
+	target.SetUint(iv)
+	return nil
+}
+
+func fromCtyNumberFloat(bf *big.Float, target reflect.Value, path cty.Path) error {
+	switch target.Kind() {
+	case reflect.Float32, reflect.Float64:
+		fv, accuracy := bf.Float64()
+		if accuracy != big.Exact {
+			// We allow the precision to be truncated as part of our conversion,
+			// but we don't want to silently introduce infinities.
+			if math.IsInf(fv, 0) {
+				return path.NewErrorf("value must be between %f and %f inclusive", -math.MaxFloat64, math.MaxFloat64)
+			}
+		}
+		target.SetFloat(fv)
+		return nil
+	default:
+		panic("unsupported kind of float")
+	}
+}
+
+func fromCtyNumberBig(bf *big.Float, target reflect.Value, path cty.Path) error {
+	switch {
+
+	case bigFloatType.ConvertibleTo(target.Type()):
+		// Easy!
+		target.Set(reflect.ValueOf(bf).Elem().Convert(target.Type()))
+		return nil
+
+	case bigIntType.ConvertibleTo(target.Type()):
+		bi, accuracy := bf.Int(nil)
+		if accuracy != big.Exact {
+			return path.NewErrorf("value must be a whole number")
+		}
+		target.Set(reflect.ValueOf(bi).Elem().Convert(target.Type()))
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+	}
+}
+
+func fromCtyString(val cty.Value, target reflect.Value, path cty.Path) error {
+	switch target.Kind() {
+	case reflect.String:
+		target.SetString(val.AsString())
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyList(val cty.Value, target reflect.Value, path cty.Path) error {
+	switch target.Kind() {
+
+	case reflect.Slice:
+		if val.IsNull() {
+			target.Set(reflect.Zero(target.Type()))
+			return nil
+		}
+
+		length := val.LengthInt()
+		tv := reflect.MakeSlice(target.Type(), length, length)
+
+		path = append(path, nil)
+
+		i := 0
+		var err error
+		val.ForEachElement(func(key cty.Value, val cty.Value) bool {
+			path[len(path)-1] = cty.IndexStep{
+				Key: cty.NumberIntVal(int64(i)),
+			}
+
+			targetElem := tv.Index(i)
+			err = fromCtyValue(val, targetElem, path)
+			if err != nil {
+				return true
+			}
+
+			i++
+			return false
+		})
+		if err != nil {
+			return err
+		}
+
+		path = path[:len(path)-1]
+
+		target.Set(tv)
+		return nil
+
+	case reflect.Array:
+		if val.IsNull() {
+			return path.NewErrorf("null value is not allowed")
+		}
+
+		length := val.LengthInt()
+		if length != target.Len() {
+			return path.NewErrorf("must be a list of length %d", target.Len())
+		}
+
+		path = append(path, nil)
+
+		i := 0
+		var err error
+		val.ForEachElement(func(key cty.Value, val cty.Value) bool {
+			path[len(path)-1] = cty.IndexStep{
+				Key: cty.NumberIntVal(int64(i)),
+			}
+
+			targetElem := target.Index(i)
+			err = fromCtyValue(val, targetElem, path)
+			if err != nil {
+				return true
+			}
+
+			i++
+			return false
+		})
+		if err != nil {
+			return err
+		}
+
+		path = path[:len(path)-1]
+
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyMap(val cty.Value, target reflect.Value, path cty.Path) error {
+
+	switch target.Kind() {
+
+	case reflect.Map:
+		if val.IsNull() {
+			target.Set(reflect.Zero(target.Type()))
+			return nil
+		}
+
+		tv := reflect.MakeMap(target.Type())
+		et := target.Type().Elem()
+
+		path = append(path, nil)
+
+		var err error
+		val.ForEachElement(func(key cty.Value, val cty.Value) bool {
+			path[len(path)-1] = cty.IndexStep{
+				Key: key,
+			}
+
+			ks := key.AsString()
+
+			targetElem := reflect.New(et)
+			err = fromCtyValue(val, targetElem, path)
+
+			tv.SetMapIndex(reflect.ValueOf(ks), targetElem.Elem())
+
+			return err != nil
+		})
+		if err != nil {
+			return err
+		}
+
+		path = path[:len(path)-1]
+
+		target.Set(tv)
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtySet(val cty.Value, target reflect.Value, path cty.Path) error {
+	switch target.Kind() {
+
+	case reflect.Slice:
+		if val.IsNull() {
+			target.Set(reflect.Zero(target.Type()))
+			return nil
+		}
+
+		length := val.LengthInt()
+		tv := reflect.MakeSlice(target.Type(), length, length)
+
+		i := 0
+		var err error
+		val.ForEachElement(func(key cty.Value, val cty.Value) bool {
+			targetElem := tv.Index(i)
+			err = fromCtyValue(val, targetElem, path)
+			if err != nil {
+				return true
+			}
+
+			i++
+			return false
+		})
+		if err != nil {
+			return err
+		}
+
+		target.Set(tv)
+		return nil
+
+	case reflect.Array:
+		if val.IsNull() {
+			return path.NewErrorf("null value is not allowed")
+		}
+
+		length := val.LengthInt()
+		if length != target.Len() {
+			return path.NewErrorf("must be a set of length %d", target.Len())
+		}
+
+		i := 0
+		var err error
+		val.ForEachElement(func(key cty.Value, val cty.Value) bool {
+			targetElem := target.Index(i)
+			err = fromCtyValue(val, targetElem, path)
+			if err != nil {
+				return true
+			}
+
+			i++
+			return false
+		})
+		if err != nil {
+			return err
+		}
+
+		return nil
+
+	// TODO: decode into set.Set instance
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyObject(val cty.Value, target reflect.Value, path cty.Path) error {
+
+	switch target.Kind() {
+
+	case reflect.Struct:
+
+		attrTypes := val.Type().AttributeTypes()
+		targetFields := structTagIndices(target.Type())
+
+		path = append(path, nil)
+
+		for k, i := range targetFields {
+			if _, exists := attrTypes[k]; !exists {
+				// If the field in question isn't able to represent nil,
+				// that's an error.
+				fk := target.Field(i).Kind()
+				switch fk {
+				case reflect.Ptr, reflect.Slice, reflect.Map, reflect.Interface:
+					// okay
+				default:
+					return path.NewErrorf("missing required attribute %q", k)
+				}
+			}
+		}
+
+		for k := range attrTypes {
+			path[len(path)-1] = cty.GetAttrStep{
+				Name: k,
+			}
+
+			fieldIdx, exists := targetFields[k]
+			if !exists {
+				return path.NewErrorf("unsupported attribute %q", k)
+			}
+
+			ev := val.GetAttr(k)
+
+			targetField := target.Field(fieldIdx)
+			err := fromCtyValue(ev, targetField, path)
+			if err != nil {
+				return err
+			}
+		}
+
+		path = path[:len(path)-1]
+
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyTuple(val cty.Value, target reflect.Value, path cty.Path) error {
+
+	switch target.Kind() {
+
+	case reflect.Struct:
+
+		elemTypes := val.Type().TupleElementTypes()
+		fieldCount := target.Type().NumField()
+
+		if fieldCount != len(elemTypes) {
+			return path.NewErrorf("a tuple of %d elements is required", fieldCount)
+		}
+
+		path = append(path, nil)
+
+		for i := range elemTypes {
+			path[len(path)-1] = cty.IndexStep{
+				Key: cty.NumberIntVal(int64(i)),
+			}
+
+			ev := val.Index(cty.NumberIntVal(int64(i)))
+
+			targetField := target.Field(i)
+			err := fromCtyValue(ev, targetField, path)
+			if err != nil {
+				return err
+			}
+		}
+
+		path = path[:len(path)-1]
+
+		return nil
+
+	default:
+		return likelyRequiredTypesError(path, target)
+
+	}
+}
+
+func fromCtyCapsule(val cty.Value, target reflect.Value, path cty.Path) error {
+
+	if target.Kind() == reflect.Ptr {
+		// Walk through indirection until we get to the last pointer,
+		// which we might set to null below.
+		target = fromCtyPopulatePtr(target, true)
+
+		if val.IsNull() {
+			target.Set(reflect.Zero(target.Type()))
+			return nil
+		}
+
+		// Since a capsule contains a pointer to an object, we'll preserve
+		// that pointer on the way out and thus allow the caller to recover
+		// the original object, rather than a copy of it.
+
+		eType := val.Type().EncapsulatedType()
+
+		if !eType.AssignableTo(target.Elem().Type()) {
+			// Our interface contract promises that we won't expose Go
+			// implementation details in error messages, so we need to keep
+			// this vague. This can only arise if a calling application has
+			// more than one capsule type in play and a user mixes them up.
+			return path.NewErrorf("incorrect type %s", val.Type().FriendlyName())
+		}
+
+		target.Set(reflect.ValueOf(val.EncapsulatedValue()))
+
+		return nil
+	} else {
+		if val.IsNull() {
+			return path.NewErrorf("null value is not allowed")
+		}
+
+		// If our target isn't a pointer then we will attempt to copy
+		// the encapsulated value into it.
+
+		eType := val.Type().EncapsulatedType()
+
+		if !eType.AssignableTo(target.Type()) {
+			// Our interface contract promises that we won't expose Go
+			// implementation details in error messages, so we need to keep
+			// this vague. This can only arise if a calling application has
+			// more than one capsule type in play and a user mixes them up.
+			return path.NewErrorf("incorrect type %s", val.Type().FriendlyName())
+		}
+
+		// We know that EncapsulatedValue is always a pointer, so we
+		// can safely call .Elem on its reflect.Value.
+		target.Set(reflect.ValueOf(val.EncapsulatedValue()).Elem())
+
+		return nil
+	}
+
+}
+
+// fromCtyPopulatePtr recognizes when target is a pointer type and allocates
+// a value to assign to that pointer, which it returns.
+//
+// If the given value has multiple levels of indirection, like **int, these
+// will be processed in turn so that the return value is guaranteed to be
+// a non-pointer.
+//
+// As an exception, if decodingNull is true then the returned value will be
+// the final level of pointer, if any, so that the caller can assign it
+// as nil to represent a null value. If the given target value is not a pointer
+// at all then the returned value will be just the given target, so the caller
+// must test if the returned value is a pointer before trying to assign nil
+// to it.
+func fromCtyPopulatePtr(target reflect.Value, decodingNull bool) reflect.Value {
+	for {
+		if target.Kind() == reflect.Interface && !target.IsNil() {
+			e := target.Elem()
+			if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
+				target = e
+			}
+		}
+
+		if target.Kind() != reflect.Ptr {
+			break
+		}
+
+		// Stop early if we're decodingNull and we've found our last indirection
+		if target.Elem().Kind() != reflect.Ptr && decodingNull && target.CanSet() {
+			break
+		}
+
+		if target.IsNil() {
+			target.Set(reflect.New(target.Type().Elem()))
+		}
+
+		target = target.Elem()
+	}
+	return target
+}
+
+// likelyRequiredTypesError returns an error that states which types are
+// acceptable by making some assumptions about what types we support for
+// each target Go kind. It's not a precise science but it allows us to return
+// an error message that is cty-user-oriented rather than Go-oriented.
+//
+// Generally these error messages should be a matter of last resort, since
+// the calling application should be validating user-provided value types
+// before decoding anyway.
+func likelyRequiredTypesError(path cty.Path, target reflect.Value) error {
+	switch target.Kind() {
+
+	case reflect.Bool:
+		return path.NewErrorf("bool value is required")
+
+	case reflect.String:
+		return path.NewErrorf("string value is required")
+
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		fallthrough
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		fallthrough
+	case reflect.Float32, reflect.Float64:
+		return path.NewErrorf("number value is required")
+
+	case reflect.Slice, reflect.Array:
+		return path.NewErrorf("list or set value is required")
+
+	case reflect.Map:
+		return path.NewErrorf("map or object value is required")
+
+	case reflect.Struct:
+		switch {
+
+		case target.Type().AssignableTo(bigFloatType) || target.Type().AssignableTo(bigIntType):
+			return path.NewErrorf("number value is required")
+
+		case target.Type().AssignableTo(setType):
+			return path.NewErrorf("set or list value is required")
+
+		default:
+			return path.NewErrorf("object or tuple value is required")
+
+		}
+
+	default:
+		// We should avoid getting into this path, since this error
+		// message is rather useless.
+		return path.NewErrorf("incorrect type")
+
+	}
+}