woodpecker/vendor/github.com/cloudfoundry-incubator/candiedyaml/decode.go
2016-04-16 00:51:05 -07:00

622 lines
13 KiB
Go

/*
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package candiedyaml
import (
"bytes"
"errors"
"fmt"
"io"
"reflect"
"runtime"
"strconv"
"strings"
)
type Unmarshaler interface {
UnmarshalYAML(tag string, value interface{}) error
}
// A Number represents a JSON number literal.
type Number string
// String returns the literal text of the number.
func (n Number) String() string { return string(n) }
// Float64 returns the number as a float64.
func (n Number) Float64() (float64, error) {
return strconv.ParseFloat(string(n), 64)
}
// Int64 returns the number as an int64.
func (n Number) Int64() (int64, error) {
return strconv.ParseInt(string(n), 10, 64)
}
type Decoder struct {
parser yaml_parser_t
event yaml_event_t
replay_events []yaml_event_t
useNumber bool
anchors map[string][]yaml_event_t
tracking_anchors [][]yaml_event_t
}
type ParserError struct {
ErrorType YAML_error_type_t
Context string
ContextMark YAML_mark_t
Problem string
ProblemMark YAML_mark_t
}
func (e *ParserError) Error() string {
return fmt.Sprintf("yaml: [%s] %s at line %d, column %d", e.Context, e.Problem, e.ProblemMark.line+1, e.ProblemMark.column+1)
}
type UnexpectedEventError struct {
Value string
EventType yaml_event_type_t
At YAML_mark_t
}
func (e *UnexpectedEventError) Error() string {
return fmt.Sprintf("yaml: Unexpect event [%d]: '%s' at line %d, column %d", e.EventType, e.Value, e.At.line+1, e.At.column+1)
}
func recovery(err *error) {
if r := recover(); r != nil {
if _, ok := r.(runtime.Error); ok {
panic(r)
}
var tmpError error
switch r := r.(type) {
case error:
tmpError = r
case string:
tmpError = errors.New(r)
default:
tmpError = errors.New("Unknown panic: " + reflect.ValueOf(r).String())
}
*err = tmpError
}
}
func Unmarshal(data []byte, v interface{}) error {
d := NewDecoder(bytes.NewBuffer(data))
return d.Decode(v)
}
func NewDecoder(r io.Reader) *Decoder {
d := &Decoder{
anchors: make(map[string][]yaml_event_t),
tracking_anchors: make([][]yaml_event_t, 1),
}
yaml_parser_initialize(&d.parser)
yaml_parser_set_input_reader(&d.parser, r)
return d
}
func (d *Decoder) Decode(v interface{}) (err error) {
defer recovery(&err)
rv := reflect.ValueOf(v)
if rv.Kind() != reflect.Ptr || rv.IsNil() {
return fmt.Errorf("Expected a pointer or nil but was a %s at %s", rv.String(), d.event.start_mark)
}
if d.event.event_type == yaml_NO_EVENT {
d.nextEvent()
if d.event.event_type != yaml_STREAM_START_EVENT {
return errors.New("Invalid stream")
}
d.nextEvent()
}
d.document(rv)
return nil
}
func (d *Decoder) UseNumber() { d.useNumber = true }
func (d *Decoder) error(err error) {
panic(err)
}
func (d *Decoder) nextEvent() {
if d.event.event_type == yaml_STREAM_END_EVENT {
d.error(errors.New("The stream is closed"))
}
if d.replay_events != nil {
d.event = d.replay_events[0]
if len(d.replay_events) == 1 {
d.replay_events = nil
} else {
d.replay_events = d.replay_events[1:]
}
} else {
if !yaml_parser_parse(&d.parser, &d.event) {
yaml_event_delete(&d.event)
d.error(&ParserError{
ErrorType: d.parser.error,
Context: d.parser.context,
ContextMark: d.parser.context_mark,
Problem: d.parser.problem,
ProblemMark: d.parser.problem_mark,
})
}
}
last := len(d.tracking_anchors)
// skip aliases when tracking an anchor
if last > 0 && d.event.event_type != yaml_ALIAS_EVENT {
d.tracking_anchors[last-1] = append(d.tracking_anchors[last-1], d.event)
}
}
func (d *Decoder) document(rv reflect.Value) {
if d.event.event_type != yaml_DOCUMENT_START_EVENT {
d.error(fmt.Errorf("Expected document start at %s", d.event.start_mark))
}
d.nextEvent()
d.parse(rv)
if d.event.event_type != yaml_DOCUMENT_END_EVENT {
d.error(fmt.Errorf("Expected document end at %s", d.event.start_mark))
}
d.nextEvent()
}
func (d *Decoder) parse(rv reflect.Value) {
if !rv.IsValid() {
// skip ahead since we cannot store
d.valueInterface()
return
}
anchor := string(d.event.anchor)
switch d.event.event_type {
case yaml_SEQUENCE_START_EVENT:
d.begin_anchor(anchor)
d.sequence(rv)
d.end_anchor(anchor)
case yaml_MAPPING_START_EVENT:
d.begin_anchor(anchor)
d.mapping(rv)
d.end_anchor(anchor)
case yaml_SCALAR_EVENT:
d.begin_anchor(anchor)
d.scalar(rv)
d.end_anchor(anchor)
case yaml_ALIAS_EVENT:
d.alias(rv)
case yaml_DOCUMENT_END_EVENT:
default:
d.error(&UnexpectedEventError{
Value: string(d.event.value),
EventType: d.event.event_type,
At: d.event.start_mark,
})
}
}
func (d *Decoder) begin_anchor(anchor string) {
if anchor != "" {
events := []yaml_event_t{d.event}
d.tracking_anchors = append(d.tracking_anchors, events)
}
}
func (d *Decoder) end_anchor(anchor string) {
if anchor != "" {
events := d.tracking_anchors[len(d.tracking_anchors)-1]
d.tracking_anchors = d.tracking_anchors[0 : len(d.tracking_anchors)-1]
// remove the anchor, replaying events shouldn't have anchors
events[0].anchor = nil
// we went one too many, remove the extra event
events = events[:len(events)-1]
// if nested, append to all the other anchors
for i, e := range d.tracking_anchors {
d.tracking_anchors[i] = append(e, events...)
}
d.anchors[anchor] = events
}
}
func (d *Decoder) indirect(v reflect.Value, decodingNull bool) (Unmarshaler, reflect.Value) {
// If v is a named type and is addressable,
// start with its address, so that if the type has pointer methods,
// we find them.
if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
v = v.Addr()
}
for {
// Load value from interface, but only if the result will be
// usefully addressable.
if v.Kind() == reflect.Interface && !v.IsNil() {
e := v.Elem()
if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
v = e
continue
}
}
if v.Kind() != reflect.Ptr {
break
}
if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
break
}
if v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
if v.Type().NumMethod() > 0 {
if u, ok := v.Interface().(Unmarshaler); ok {
var temp interface{}
return u, reflect.ValueOf(&temp)
}
}
v = v.Elem()
}
return nil, v
}
func (d *Decoder) sequence(v reflect.Value) {
if d.event.event_type != yaml_SEQUENCE_START_EVENT {
d.error(fmt.Errorf("Expected sequence start at %s", d.event.start_mark))
}
u, pv := d.indirect(v, false)
if u != nil {
defer func() {
if err := u.UnmarshalYAML(yaml_SEQ_TAG, pv.Interface()); err != nil {
d.error(err)
}
}()
_, pv = d.indirect(pv, false)
}
v = pv
// Check type of target.
switch v.Kind() {
case reflect.Interface:
if v.NumMethod() == 0 {
// Decoding into nil interface? Switch to non-reflect code.
v.Set(reflect.ValueOf(d.sequenceInterface()))
return
}
// Otherwise it's invalid.
fallthrough
default:
d.error(fmt.Errorf("Expected an array, slice or interface{} but was a %s at %s", v, d.event.start_mark))
case reflect.Array:
case reflect.Slice:
break
}
d.nextEvent()
i := 0
done:
for {
switch d.event.event_type {
case yaml_SEQUENCE_END_EVENT, yaml_DOCUMENT_END_EVENT:
break done
}
// Get element of array, growing if necessary.
if v.Kind() == reflect.Slice {
// Grow slice if necessary
if i >= v.Cap() {
newcap := v.Cap() + v.Cap()/2
if newcap < 4 {
newcap = 4
}
newv := reflect.MakeSlice(v.Type(), v.Len(), newcap)
reflect.Copy(newv, v)
v.Set(newv)
}
if i >= v.Len() {
v.SetLen(i + 1)
}
}
if i < v.Len() {
// Decode into element.
d.parse(v.Index(i))
} else {
// Ran out of fixed array: skip.
d.parse(reflect.Value{})
}
i++
}
if i < v.Len() {
if v.Kind() == reflect.Array {
// Array. Zero the rest.
z := reflect.Zero(v.Type().Elem())
for ; i < v.Len(); i++ {
v.Index(i).Set(z)
}
} else {
v.SetLen(i)
}
}
if i == 0 && v.Kind() == reflect.Slice {
v.Set(reflect.MakeSlice(v.Type(), 0, 0))
}
if d.event.event_type != yaml_DOCUMENT_END_EVENT {
d.nextEvent()
}
}
func (d *Decoder) mapping(v reflect.Value) {
u, pv := d.indirect(v, false)
if u != nil {
defer func() {
if err := u.UnmarshalYAML(yaml_MAP_TAG, pv.Interface()); err != nil {
d.error(err)
}
}()
_, pv = d.indirect(pv, false)
}
v = pv
// Decoding into nil interface? Switch to non-reflect code.
if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
v.Set(reflect.ValueOf(d.mappingInterface()))
return
}
// Check type of target: struct or map[X]Y
switch v.Kind() {
case reflect.Struct:
d.mappingStruct(v)
return
case reflect.Map:
default:
d.error(fmt.Errorf("Expected a struct or map but was a %s at %s ", v, d.event.start_mark))
}
mapt := v.Type()
if v.IsNil() {
v.Set(reflect.MakeMap(mapt))
}
d.nextEvent()
keyt := mapt.Key()
mapElemt := mapt.Elem()
var mapElem reflect.Value
done:
for {
switch d.event.event_type {
case yaml_MAPPING_END_EVENT:
break done
case yaml_DOCUMENT_END_EVENT:
return
}
key := reflect.New(keyt)
d.parse(key.Elem())
if !mapElem.IsValid() {
mapElem = reflect.New(mapElemt).Elem()
} else {
mapElem.Set(reflect.Zero(mapElemt))
}
d.parse(mapElem)
v.SetMapIndex(key.Elem(), mapElem)
}
d.nextEvent()
}
func (d *Decoder) mappingStruct(v reflect.Value) {
structt := v.Type()
fields := cachedTypeFields(structt)
d.nextEvent()
done:
for {
switch d.event.event_type {
case yaml_MAPPING_END_EVENT:
break done
case yaml_DOCUMENT_END_EVENT:
return
}
key := ""
d.parse(reflect.ValueOf(&key))
// Figure out field corresponding to key.
var subv reflect.Value
var f *field
for i := range fields {
ff := &fields[i]
if ff.name == key {
f = ff
break
}
if f == nil && strings.EqualFold(ff.name, key) {
f = ff
}
}
if f != nil {
subv = v
for _, i := range f.index {
if subv.Kind() == reflect.Ptr {
if subv.IsNil() {
subv.Set(reflect.New(subv.Type().Elem()))
}
subv = subv.Elem()
}
subv = subv.Field(i)
}
}
d.parse(subv)
}
d.nextEvent()
}
func (d *Decoder) scalar(v reflect.Value) {
val := string(d.event.value)
wantptr := null_values[val]
u, pv := d.indirect(v, wantptr)
var tag string
if u != nil {
defer func() {
if err := u.UnmarshalYAML(tag, pv.Interface()); err != nil {
d.error(err)
}
}()
_, pv = d.indirect(pv, wantptr)
}
v = pv
var err error
tag, err = resolve(d.event, v, d.useNumber)
if err != nil {
d.error(err)
}
d.nextEvent()
}
func (d *Decoder) alias(rv reflect.Value) {
val, ok := d.anchors[string(d.event.anchor)]
if !ok {
d.error(fmt.Errorf("missing anchor: '%s' at %s", d.event.anchor, d.event.start_mark))
}
d.replay_events = val
d.nextEvent()
d.parse(rv)
}
func (d *Decoder) valueInterface() interface{} {
var v interface{}
anchor := string(d.event.anchor)
switch d.event.event_type {
case yaml_SEQUENCE_START_EVENT:
d.begin_anchor(anchor)
v = d.sequenceInterface()
case yaml_MAPPING_START_EVENT:
d.begin_anchor(anchor)
v = d.mappingInterface()
case yaml_SCALAR_EVENT:
d.begin_anchor(anchor)
v = d.scalarInterface()
case yaml_ALIAS_EVENT:
rv := reflect.ValueOf(&v)
d.alias(rv)
return v
case yaml_DOCUMENT_END_EVENT:
d.error(&UnexpectedEventError{
Value: string(d.event.value),
EventType: d.event.event_type,
At: d.event.start_mark,
})
}
d.end_anchor(anchor)
return v
}
func (d *Decoder) scalarInterface() interface{} {
_, v := resolveInterface(d.event, d.useNumber)
d.nextEvent()
return v
}
// sequenceInterface is like sequence but returns []interface{}.
func (d *Decoder) sequenceInterface() []interface{} {
var v = make([]interface{}, 0)
d.nextEvent()
done:
for {
switch d.event.event_type {
case yaml_SEQUENCE_END_EVENT, yaml_DOCUMENT_END_EVENT:
break done
}
v = append(v, d.valueInterface())
}
if d.event.event_type != yaml_DOCUMENT_END_EVENT {
d.nextEvent()
}
return v
}
// mappingInterface is like mapping but returns map[interface{}]interface{}.
func (d *Decoder) mappingInterface() map[interface{}]interface{} {
m := make(map[interface{}]interface{})
d.nextEvent()
done:
for {
switch d.event.event_type {
case yaml_MAPPING_END_EVENT, yaml_DOCUMENT_END_EVENT:
break done
}
key := d.valueInterface()
// Read value.
m[key] = d.valueInterface()
}
if d.event.event_type != yaml_DOCUMENT_END_EVENT {
d.nextEvent()
}
return m
}