terraform-provider-gitea/vendor/github.com/zclconf/go-cty/cty/gocty/out.go

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2022-04-03 04:07:16 +00:00
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")
}
}