packer-cn/vendor/github.com/zclconf/go-cty/cty/convert/conversion_object.go

77 lines
2.0 KiB
Go

package convert
import (
"github.com/zclconf/go-cty/cty"
)
// conversionObjectToObject returns a conversion that will make the input
// object type conform to the output object type, if possible.
//
// Conversion is possible only if the output type is a subset of the input
// type, meaning that each attribute of the output type has a corresponding
// attribute in the input type where a recursive conversion is available.
//
// Shallow object conversions work the same for both safe and unsafe modes,
// but the safety flag is passed on to recursive conversions and may thus
// limit the above definition of "subset".
func conversionObjectToObject(in, out cty.Type, unsafe bool) conversion {
inAtys := in.AttributeTypes()
outAtys := out.AttributeTypes()
attrConvs := make(map[string]conversion)
for name, outAty := range outAtys {
inAty, exists := inAtys[name]
if !exists {
// No conversion is available, then.
return nil
}
if inAty.Equals(outAty) {
// No conversion needed, but we'll still record the attribute
// in our map for later reference.
attrConvs[name] = nil
continue
}
attrConvs[name] = getConversion(inAty, outAty, unsafe)
if attrConvs[name] == nil {
// If a recursive conversion isn't available, then our top-level
// configuration is impossible too.
return nil
}
}
// If we get here then a conversion is possible, using the attribute
// conversions given in attrConvs.
return func(val cty.Value, path cty.Path) (cty.Value, error) {
attrVals := make(map[string]cty.Value, len(attrConvs))
path = append(path, nil)
pathStep := &path[len(path)-1]
for it := val.ElementIterator(); it.Next(); {
nameVal, val := it.Element()
var err error
name := nameVal.AsString()
*pathStep = cty.GetAttrStep{
Name: name,
}
conv, exists := attrConvs[name]
if !exists {
continue
}
if conv != nil {
val, err = conv(val, path)
if err != nil {
return cty.NilVal, err
}
}
attrVals[name] = val
}
return cty.ObjectVal(attrVals), nil
}
}