terraformDummyRepo2/vendor/github.com/zclconf/go-cty-yaml/decode.go
Malar Invention 00ebcd295e add vendor
2022-04-03 09:37:16 +05:30

261 lines
7 KiB
Go

package yaml
import (
"errors"
"fmt"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
)
func (c *Converter) unmarshal(src []byte, ty cty.Type) (cty.Value, error) {
p := &yaml_parser_t{}
if !yaml_parser_initialize(p) {
return cty.NilVal, errors.New("failed to initialize YAML parser")
}
if len(src) == 0 {
src = []byte{'\n'}
}
an := &valueAnalysis{
anchorsPending: map[string]int{},
anchorVals: map[string]cty.Value{},
}
yaml_parser_set_input_string(p, src)
var evt yaml_event_t
if !yaml_parser_parse(p, &evt) {
return cty.NilVal, parserError(p)
}
if evt.typ != yaml_STREAM_START_EVENT {
return cty.NilVal, parseEventErrorf(&evt, "missing stream start token")
}
if !yaml_parser_parse(p, &evt) {
return cty.NilVal, parserError(p)
}
if evt.typ != yaml_DOCUMENT_START_EVENT {
return cty.NilVal, parseEventErrorf(&evt, "missing start of document")
}
v, err := c.unmarshalParse(an, p)
if err != nil {
return cty.NilVal, err
}
if !yaml_parser_parse(p, &evt) {
return cty.NilVal, parserError(p)
}
if evt.typ == yaml_DOCUMENT_START_EVENT {
return cty.NilVal, parseEventErrorf(&evt, "only a single document is allowed")
}
if evt.typ != yaml_DOCUMENT_END_EVENT {
return cty.NilVal, parseEventErrorf(&evt, "unexpected extra content (%s) after value", evt.typ.String())
}
if !yaml_parser_parse(p, &evt) {
return cty.NilVal, parserError(p)
}
if evt.typ != yaml_STREAM_END_EVENT {
return cty.NilVal, parseEventErrorf(&evt, "unexpected extra content after value")
}
return convert.Convert(v, ty)
}
func (c *Converter) unmarshalParse(an *valueAnalysis, p *yaml_parser_t) (cty.Value, error) {
var evt yaml_event_t
if !yaml_parser_parse(p, &evt) {
return cty.NilVal, parserError(p)
}
return c.unmarshalParseRemainder(an, &evt, p)
}
func (c *Converter) unmarshalParseRemainder(an *valueAnalysis, evt *yaml_event_t, p *yaml_parser_t) (cty.Value, error) {
switch evt.typ {
case yaml_SCALAR_EVENT:
return c.unmarshalScalar(an, evt, p)
case yaml_ALIAS_EVENT:
return c.unmarshalAlias(an, evt, p)
case yaml_MAPPING_START_EVENT:
return c.unmarshalMapping(an, evt, p)
case yaml_SEQUENCE_START_EVENT:
return c.unmarshalSequence(an, evt, p)
case yaml_DOCUMENT_START_EVENT:
return cty.NilVal, parseEventErrorf(evt, "only a single document is allowed")
case yaml_STREAM_END_EVENT:
// Decoding an empty buffer, probably
return cty.NilVal, parseEventErrorf(evt, "expecting value but found end of stream")
default:
// Should never happen; the above should be comprehensive
return cty.NilVal, parseEventErrorf(evt, "unexpected parser event %s", evt.typ.String())
}
}
func (c *Converter) unmarshalScalar(an *valueAnalysis, evt *yaml_event_t, p *yaml_parser_t) (cty.Value, error) {
src := evt.value
tag := string(evt.tag)
anchor := string(evt.anchor)
if len(anchor) > 0 {
an.beginAnchor(anchor)
}
val, err := c.resolveScalar(tag, string(src), yaml_scalar_style_t(evt.style))
if err != nil {
return cty.NilVal, parseEventErrorWrap(evt, err)
}
if val.RawEquals(mergeMappingVal) {
// In any context other than a mapping key, this is just a plain string
val = cty.StringVal("<<")
}
if len(anchor) > 0 {
an.completeAnchor(anchor, val)
}
return val, nil
}
func (c *Converter) unmarshalMapping(an *valueAnalysis, evt *yaml_event_t, p *yaml_parser_t) (cty.Value, error) {
tag := string(evt.tag)
anchor := string(evt.anchor)
if tag != "" && tag != yaml_MAP_TAG {
return cty.NilVal, parseEventErrorf(evt, "can't interpret mapping as %s", tag)
}
if anchor != "" {
an.beginAnchor(anchor)
}
vals := make(map[string]cty.Value)
for {
var nextEvt yaml_event_t
if !yaml_parser_parse(p, &nextEvt) {
return cty.NilVal, parserError(p)
}
if nextEvt.typ == yaml_MAPPING_END_EVENT {
v := cty.ObjectVal(vals)
if anchor != "" {
an.completeAnchor(anchor, v)
}
return v, nil
}
if nextEvt.typ != yaml_SCALAR_EVENT {
return cty.NilVal, parseEventErrorf(&nextEvt, "only strings are allowed as mapping keys")
}
keyVal, err := c.resolveScalar(string(nextEvt.tag), string(nextEvt.value), yaml_scalar_style_t(nextEvt.style))
if err != nil {
return cty.NilVal, err
}
if keyVal.RawEquals(mergeMappingVal) {
// Merging the value (which must be a mapping) into our mapping,
// then.
val, err := c.unmarshalParse(an, p)
if err != nil {
return cty.NilVal, err
}
ty := val.Type()
if !(ty.IsObjectType() || ty.IsMapType()) {
return cty.NilVal, parseEventErrorf(&nextEvt, "cannot merge %s into mapping", ty.FriendlyName())
}
for it := val.ElementIterator(); it.Next(); {
k, v := it.Element()
vals[k.AsString()] = v
}
continue
}
if keyValStr, err := convert.Convert(keyVal, cty.String); err == nil {
keyVal = keyValStr
} else {
return cty.NilVal, parseEventErrorf(&nextEvt, "only strings are allowed as mapping keys")
}
if keyVal.IsNull() {
return cty.NilVal, parseEventErrorf(&nextEvt, "mapping key cannot be null")
}
if !keyVal.IsKnown() {
return cty.NilVal, parseEventErrorf(&nextEvt, "mapping key must be known")
}
val, err := c.unmarshalParse(an, p)
if err != nil {
return cty.NilVal, err
}
vals[keyVal.AsString()] = val
}
}
func (c *Converter) unmarshalSequence(an *valueAnalysis, evt *yaml_event_t, p *yaml_parser_t) (cty.Value, error) {
tag := string(evt.tag)
anchor := string(evt.anchor)
if tag != "" && tag != yaml_SEQ_TAG {
return cty.NilVal, parseEventErrorf(evt, "can't interpret sequence as %s", tag)
}
if anchor != "" {
an.beginAnchor(anchor)
}
var vals []cty.Value
for {
var nextEvt yaml_event_t
if !yaml_parser_parse(p, &nextEvt) {
return cty.NilVal, parserError(p)
}
if nextEvt.typ == yaml_SEQUENCE_END_EVENT {
ty := cty.TupleVal(vals)
if anchor != "" {
an.completeAnchor(anchor, ty)
}
return ty, nil
}
val, err := c.unmarshalParseRemainder(an, &nextEvt, p)
if err != nil {
return cty.NilVal, err
}
vals = append(vals, val)
}
}
func (c *Converter) unmarshalAlias(an *valueAnalysis, evt *yaml_event_t, p *yaml_parser_t) (cty.Value, error) {
v, err := an.anchorVal(string(evt.anchor))
if err != nil {
err = parseEventErrorWrap(evt, err)
}
return v, err
}
type valueAnalysis struct {
anchorsPending map[string]int
anchorVals map[string]cty.Value
}
func (an *valueAnalysis) beginAnchor(name string) {
an.anchorsPending[name]++
}
func (an *valueAnalysis) completeAnchor(name string, v cty.Value) {
an.anchorsPending[name]--
if an.anchorsPending[name] == 0 {
delete(an.anchorsPending, name)
}
an.anchorVals[name] = v
}
func (an *valueAnalysis) anchorVal(name string) (cty.Value, error) {
if _, pending := an.anchorsPending[name]; pending {
// YAML normally allows self-referencing structures, but cty cannot
// represent them (it requires all structures to be finite) so we
// must fail here.
return cty.NilVal, fmt.Errorf("cannot refer to anchor %q from inside its own definition", name)
}
ty, ok := an.anchorVals[name]
if !ok {
return cty.NilVal, fmt.Errorf("reference to undefined anchor %q", name)
}
return ty, nil
}