webhook/vendor/gopkg.in/yaml.v2/decode.go
Stefan Bethke b663783717 Vendor code using godep.
For 3rd parties building binary packages, and for build consistency in
general, it is very helpful to have the same set of dependencies at
any time the product is built.

See [tools/godep](https://github.com/tools/godep) for further details.
2017-10-09 20:05:32 +02:00

686 lines
15 KiB
Go

package yaml
import (
"encoding"
"encoding/base64"
"fmt"
"math"
"reflect"
"strconv"
"time"
)
const (
documentNode = 1 << iota
mappingNode
sequenceNode
scalarNode
aliasNode
)
type node struct {
kind int
line, column int
tag string
value string
implicit bool
children []*node
anchors map[string]*node
}
// ----------------------------------------------------------------------------
// Parser, produces a node tree out of a libyaml event stream.
type parser struct {
parser yaml_parser_t
event yaml_event_t
doc *node
}
func newParser(b []byte) *parser {
p := parser{}
if !yaml_parser_initialize(&p.parser) {
panic("failed to initialize YAML emitter")
}
if len(b) == 0 {
b = []byte{'\n'}
}
yaml_parser_set_input_string(&p.parser, b)
p.skip()
if p.event.typ != yaml_STREAM_START_EVENT {
panic("expected stream start event, got " + strconv.Itoa(int(p.event.typ)))
}
p.skip()
return &p
}
func (p *parser) destroy() {
if p.event.typ != yaml_NO_EVENT {
yaml_event_delete(&p.event)
}
yaml_parser_delete(&p.parser)
}
func (p *parser) skip() {
if p.event.typ != yaml_NO_EVENT {
if p.event.typ == yaml_STREAM_END_EVENT {
failf("attempted to go past the end of stream; corrupted value?")
}
yaml_event_delete(&p.event)
}
if !yaml_parser_parse(&p.parser, &p.event) {
p.fail()
}
}
func (p *parser) fail() {
var where string
var line int
if p.parser.problem_mark.line != 0 {
line = p.parser.problem_mark.line
} else if p.parser.context_mark.line != 0 {
line = p.parser.context_mark.line
}
if line != 0 {
where = "line " + strconv.Itoa(line) + ": "
}
var msg string
if len(p.parser.problem) > 0 {
msg = p.parser.problem
} else {
msg = "unknown problem parsing YAML content"
}
failf("%s%s", where, msg)
}
func (p *parser) anchor(n *node, anchor []byte) {
if anchor != nil {
p.doc.anchors[string(anchor)] = n
}
}
func (p *parser) parse() *node {
switch p.event.typ {
case yaml_SCALAR_EVENT:
return p.scalar()
case yaml_ALIAS_EVENT:
return p.alias()
case yaml_MAPPING_START_EVENT:
return p.mapping()
case yaml_SEQUENCE_START_EVENT:
return p.sequence()
case yaml_DOCUMENT_START_EVENT:
return p.document()
case yaml_STREAM_END_EVENT:
// Happens when attempting to decode an empty buffer.
return nil
default:
panic("attempted to parse unknown event: " + strconv.Itoa(int(p.event.typ)))
}
}
func (p *parser) node(kind int) *node {
return &node{
kind: kind,
line: p.event.start_mark.line,
column: p.event.start_mark.column,
}
}
func (p *parser) document() *node {
n := p.node(documentNode)
n.anchors = make(map[string]*node)
p.doc = n
p.skip()
n.children = append(n.children, p.parse())
if p.event.typ != yaml_DOCUMENT_END_EVENT {
panic("expected end of document event but got " + strconv.Itoa(int(p.event.typ)))
}
p.skip()
return n
}
func (p *parser) alias() *node {
n := p.node(aliasNode)
n.value = string(p.event.anchor)
p.skip()
return n
}
func (p *parser) scalar() *node {
n := p.node(scalarNode)
n.value = string(p.event.value)
n.tag = string(p.event.tag)
n.implicit = p.event.implicit
p.anchor(n, p.event.anchor)
p.skip()
return n
}
func (p *parser) sequence() *node {
n := p.node(sequenceNode)
p.anchor(n, p.event.anchor)
p.skip()
for p.event.typ != yaml_SEQUENCE_END_EVENT {
n.children = append(n.children, p.parse())
}
p.skip()
return n
}
func (p *parser) mapping() *node {
n := p.node(mappingNode)
p.anchor(n, p.event.anchor)
p.skip()
for p.event.typ != yaml_MAPPING_END_EVENT {
n.children = append(n.children, p.parse(), p.parse())
}
p.skip()
return n
}
// ----------------------------------------------------------------------------
// Decoder, unmarshals a node into a provided value.
type decoder struct {
doc *node
aliases map[string]bool
mapType reflect.Type
terrors []string
strict bool
}
var (
mapItemType = reflect.TypeOf(MapItem{})
durationType = reflect.TypeOf(time.Duration(0))
defaultMapType = reflect.TypeOf(map[interface{}]interface{}{})
ifaceType = defaultMapType.Elem()
)
func newDecoder(strict bool) *decoder {
d := &decoder{mapType: defaultMapType, strict: strict}
d.aliases = make(map[string]bool)
return d
}
func (d *decoder) terror(n *node, tag string, out reflect.Value) {
if n.tag != "" {
tag = n.tag
}
value := n.value
if tag != yaml_SEQ_TAG && tag != yaml_MAP_TAG {
if len(value) > 10 {
value = " `" + value[:7] + "...`"
} else {
value = " `" + value + "`"
}
}
d.terrors = append(d.terrors, fmt.Sprintf("line %d: cannot unmarshal %s%s into %s", n.line+1, shortTag(tag), value, out.Type()))
}
func (d *decoder) callUnmarshaler(n *node, u Unmarshaler) (good bool) {
terrlen := len(d.terrors)
err := u.UnmarshalYAML(func(v interface{}) (err error) {
defer handleErr(&err)
d.unmarshal(n, reflect.ValueOf(v))
if len(d.terrors) > terrlen {
issues := d.terrors[terrlen:]
d.terrors = d.terrors[:terrlen]
return &TypeError{issues}
}
return nil
})
if e, ok := err.(*TypeError); ok {
d.terrors = append(d.terrors, e.Errors...)
return false
}
if err != nil {
fail(err)
}
return true
}
// d.prepare initializes and dereferences pointers and calls UnmarshalYAML
// if a value is found to implement it.
// It returns the initialized and dereferenced out value, whether
// unmarshalling was already done by UnmarshalYAML, and if so whether
// its types unmarshalled appropriately.
//
// If n holds a null value, prepare returns before doing anything.
func (d *decoder) prepare(n *node, out reflect.Value) (newout reflect.Value, unmarshaled, good bool) {
if n.tag == yaml_NULL_TAG || n.kind == scalarNode && n.tag == "" && (n.value == "null" || n.value == "" && n.implicit) {
return out, false, false
}
again := true
for again {
again = false
if out.Kind() == reflect.Ptr {
if out.IsNil() {
out.Set(reflect.New(out.Type().Elem()))
}
out = out.Elem()
again = true
}
if out.CanAddr() {
if u, ok := out.Addr().Interface().(Unmarshaler); ok {
good = d.callUnmarshaler(n, u)
return out, true, good
}
}
}
return out, false, false
}
func (d *decoder) unmarshal(n *node, out reflect.Value) (good bool) {
switch n.kind {
case documentNode:
return d.document(n, out)
case aliasNode:
return d.alias(n, out)
}
out, unmarshaled, good := d.prepare(n, out)
if unmarshaled {
return good
}
switch n.kind {
case scalarNode:
good = d.scalar(n, out)
case mappingNode:
good = d.mapping(n, out)
case sequenceNode:
good = d.sequence(n, out)
default:
panic("internal error: unknown node kind: " + strconv.Itoa(n.kind))
}
return good
}
func (d *decoder) document(n *node, out reflect.Value) (good bool) {
if len(n.children) == 1 {
d.doc = n
d.unmarshal(n.children[0], out)
return true
}
return false
}
func (d *decoder) alias(n *node, out reflect.Value) (good bool) {
an, ok := d.doc.anchors[n.value]
if !ok {
failf("unknown anchor '%s' referenced", n.value)
}
if d.aliases[n.value] {
failf("anchor '%s' value contains itself", n.value)
}
d.aliases[n.value] = true
good = d.unmarshal(an, out)
delete(d.aliases, n.value)
return good
}
var zeroValue reflect.Value
func resetMap(out reflect.Value) {
for _, k := range out.MapKeys() {
out.SetMapIndex(k, zeroValue)
}
}
func (d *decoder) scalar(n *node, out reflect.Value) (good bool) {
var tag string
var resolved interface{}
if n.tag == "" && !n.implicit {
tag = yaml_STR_TAG
resolved = n.value
} else {
tag, resolved = resolve(n.tag, n.value)
if tag == yaml_BINARY_TAG {
data, err := base64.StdEncoding.DecodeString(resolved.(string))
if err != nil {
failf("!!binary value contains invalid base64 data")
}
resolved = string(data)
}
}
if resolved == nil {
if out.Kind() == reflect.Map && !out.CanAddr() {
resetMap(out)
} else {
out.Set(reflect.Zero(out.Type()))
}
return true
}
if s, ok := resolved.(string); ok && out.CanAddr() {
if u, ok := out.Addr().Interface().(encoding.TextUnmarshaler); ok {
err := u.UnmarshalText([]byte(s))
if err != nil {
fail(err)
}
return true
}
}
switch out.Kind() {
case reflect.String:
if tag == yaml_BINARY_TAG {
out.SetString(resolved.(string))
good = true
} else if resolved != nil {
out.SetString(n.value)
good = true
}
case reflect.Interface:
if resolved == nil {
out.Set(reflect.Zero(out.Type()))
} else {
out.Set(reflect.ValueOf(resolved))
}
good = true
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
switch resolved := resolved.(type) {
case int:
if !out.OverflowInt(int64(resolved)) {
out.SetInt(int64(resolved))
good = true
}
case int64:
if !out.OverflowInt(resolved) {
out.SetInt(resolved)
good = true
}
case uint64:
if resolved <= math.MaxInt64 && !out.OverflowInt(int64(resolved)) {
out.SetInt(int64(resolved))
good = true
}
case float64:
if resolved <= math.MaxInt64 && !out.OverflowInt(int64(resolved)) {
out.SetInt(int64(resolved))
good = true
}
case string:
if out.Type() == durationType {
d, err := time.ParseDuration(resolved)
if err == nil {
out.SetInt(int64(d))
good = true
}
}
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
switch resolved := resolved.(type) {
case int:
if resolved >= 0 && !out.OverflowUint(uint64(resolved)) {
out.SetUint(uint64(resolved))
good = true
}
case int64:
if resolved >= 0 && !out.OverflowUint(uint64(resolved)) {
out.SetUint(uint64(resolved))
good = true
}
case uint64:
if !out.OverflowUint(uint64(resolved)) {
out.SetUint(uint64(resolved))
good = true
}
case float64:
if resolved <= math.MaxUint64 && !out.OverflowUint(uint64(resolved)) {
out.SetUint(uint64(resolved))
good = true
}
}
case reflect.Bool:
switch resolved := resolved.(type) {
case bool:
out.SetBool(resolved)
good = true
}
case reflect.Float32, reflect.Float64:
switch resolved := resolved.(type) {
case int:
out.SetFloat(float64(resolved))
good = true
case int64:
out.SetFloat(float64(resolved))
good = true
case uint64:
out.SetFloat(float64(resolved))
good = true
case float64:
out.SetFloat(resolved)
good = true
}
case reflect.Ptr:
if out.Type().Elem() == reflect.TypeOf(resolved) {
// TODO DOes this make sense? When is out a Ptr except when decoding a nil value?
elem := reflect.New(out.Type().Elem())
elem.Elem().Set(reflect.ValueOf(resolved))
out.Set(elem)
good = true
}
}
if !good {
d.terror(n, tag, out)
}
return good
}
func settableValueOf(i interface{}) reflect.Value {
v := reflect.ValueOf(i)
sv := reflect.New(v.Type()).Elem()
sv.Set(v)
return sv
}
func (d *decoder) sequence(n *node, out reflect.Value) (good bool) {
l := len(n.children)
var iface reflect.Value
switch out.Kind() {
case reflect.Slice:
out.Set(reflect.MakeSlice(out.Type(), l, l))
case reflect.Interface:
// No type hints. Will have to use a generic sequence.
iface = out
out = settableValueOf(make([]interface{}, l))
default:
d.terror(n, yaml_SEQ_TAG, out)
return false
}
et := out.Type().Elem()
j := 0
for i := 0; i < l; i++ {
e := reflect.New(et).Elem()
if ok := d.unmarshal(n.children[i], e); ok {
out.Index(j).Set(e)
j++
}
}
out.Set(out.Slice(0, j))
if iface.IsValid() {
iface.Set(out)
}
return true
}
func (d *decoder) mapping(n *node, out reflect.Value) (good bool) {
switch out.Kind() {
case reflect.Struct:
return d.mappingStruct(n, out)
case reflect.Slice:
return d.mappingSlice(n, out)
case reflect.Map:
// okay
case reflect.Interface:
if d.mapType.Kind() == reflect.Map {
iface := out
out = reflect.MakeMap(d.mapType)
iface.Set(out)
} else {
slicev := reflect.New(d.mapType).Elem()
if !d.mappingSlice(n, slicev) {
return false
}
out.Set(slicev)
return true
}
default:
d.terror(n, yaml_MAP_TAG, out)
return false
}
outt := out.Type()
kt := outt.Key()
et := outt.Elem()
mapType := d.mapType
if outt.Key() == ifaceType && outt.Elem() == ifaceType {
d.mapType = outt
}
if out.IsNil() {
out.Set(reflect.MakeMap(outt))
}
l := len(n.children)
for i := 0; i < l; i += 2 {
if isMerge(n.children[i]) {
d.merge(n.children[i+1], out)
continue
}
k := reflect.New(kt).Elem()
if d.unmarshal(n.children[i], k) {
kkind := k.Kind()
if kkind == reflect.Interface {
kkind = k.Elem().Kind()
}
if kkind == reflect.Map || kkind == reflect.Slice {
failf("invalid map key: %#v", k.Interface())
}
e := reflect.New(et).Elem()
if d.unmarshal(n.children[i+1], e) {
out.SetMapIndex(k, e)
}
}
}
d.mapType = mapType
return true
}
func (d *decoder) mappingSlice(n *node, out reflect.Value) (good bool) {
outt := out.Type()
if outt.Elem() != mapItemType {
d.terror(n, yaml_MAP_TAG, out)
return false
}
mapType := d.mapType
d.mapType = outt
var slice []MapItem
var l = len(n.children)
for i := 0; i < l; i += 2 {
if isMerge(n.children[i]) {
d.merge(n.children[i+1], out)
continue
}
item := MapItem{}
k := reflect.ValueOf(&item.Key).Elem()
if d.unmarshal(n.children[i], k) {
v := reflect.ValueOf(&item.Value).Elem()
if d.unmarshal(n.children[i+1], v) {
slice = append(slice, item)
}
}
}
out.Set(reflect.ValueOf(slice))
d.mapType = mapType
return true
}
func (d *decoder) mappingStruct(n *node, out reflect.Value) (good bool) {
sinfo, err := getStructInfo(out.Type())
if err != nil {
panic(err)
}
name := settableValueOf("")
l := len(n.children)
var inlineMap reflect.Value
var elemType reflect.Type
if sinfo.InlineMap != -1 {
inlineMap = out.Field(sinfo.InlineMap)
inlineMap.Set(reflect.New(inlineMap.Type()).Elem())
elemType = inlineMap.Type().Elem()
}
for i := 0; i < l; i += 2 {
ni := n.children[i]
if isMerge(ni) {
d.merge(n.children[i+1], out)
continue
}
if !d.unmarshal(ni, name) {
continue
}
if info, ok := sinfo.FieldsMap[name.String()]; ok {
var field reflect.Value
if info.Inline == nil {
field = out.Field(info.Num)
} else {
field = out.FieldByIndex(info.Inline)
}
d.unmarshal(n.children[i+1], field)
} else if sinfo.InlineMap != -1 {
if inlineMap.IsNil() {
inlineMap.Set(reflect.MakeMap(inlineMap.Type()))
}
value := reflect.New(elemType).Elem()
d.unmarshal(n.children[i+1], value)
inlineMap.SetMapIndex(name, value)
} else if d.strict {
d.terrors = append(d.terrors, fmt.Sprintf("line %d: field %s not found in struct %s", n.line+1, name.String(), out.Type()))
}
}
return true
}
func failWantMap() {
failf("map merge requires map or sequence of maps as the value")
}
func (d *decoder) merge(n *node, out reflect.Value) {
switch n.kind {
case mappingNode:
d.unmarshal(n, out)
case aliasNode:
an, ok := d.doc.anchors[n.value]
if ok && an.kind != mappingNode {
failWantMap()
}
d.unmarshal(n, out)
case sequenceNode:
// Step backwards as earlier nodes take precedence.
for i := len(n.children) - 1; i >= 0; i-- {
ni := n.children[i]
if ni.kind == aliasNode {
an, ok := d.doc.anchors[ni.value]
if ok && an.kind != mappingNode {
failWantMap()
}
} else if ni.kind != mappingNode {
failWantMap()
}
d.unmarshal(ni, out)
}
default:
failWantMap()
}
}
func isMerge(n *node) bool {
return n.kind == scalarNode && n.value == "<<" && (n.implicit == true || n.tag == yaml_MERGE_TAG)
}