gtsocial-umbx

encode.go (14789B)

---

 //
 // Copyright (c) 2011-2019 Canonical Ltd
 //
 // 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 yaml
 
 import (
 	"encoding"
 	"fmt"
 	"io"
 	"reflect"
 	"regexp"
 	"sort"
 	"strconv"
 	"strings"
 	"time"
 	"unicode/utf8"
 )
 
 type encoder struct {
 	emitter  yaml_emitter_t
 	event    yaml_event_t
 	out      []byte
 	flow     bool
 	indent   int
 	doneInit bool
 }
 
 func newEncoder() *encoder {
 	e := &encoder{}
 	yaml_emitter_initialize(&e.emitter)
 	yaml_emitter_set_output_string(&e.emitter, &e.out)
 	yaml_emitter_set_unicode(&e.emitter, true)
 	return e
 }
 
 func newEncoderWithWriter(w io.Writer) *encoder {
 	e := &encoder{}
 	yaml_emitter_initialize(&e.emitter)
 	yaml_emitter_set_output_writer(&e.emitter, w)
 	yaml_emitter_set_unicode(&e.emitter, true)
 	return e
 }
 
 func (e *encoder) init() {
 	if e.doneInit {
 		return
 	}
 	if e.indent == 0 {
 		e.indent = 4
 	}
 	e.emitter.best_indent = e.indent
 	yaml_stream_start_event_initialize(&e.event, yaml_UTF8_ENCODING)
 	e.emit()
 	e.doneInit = true
 }
 
 func (e *encoder) finish() {
 	e.emitter.open_ended = false
 	yaml_stream_end_event_initialize(&e.event)
 	e.emit()
 }
 
 func (e *encoder) destroy() {
 	yaml_emitter_delete(&e.emitter)
 }
 
 func (e *encoder) emit() {
 	// This will internally delete the e.event value.
 	e.must(yaml_emitter_emit(&e.emitter, &e.event))
 }
 
 func (e *encoder) must(ok bool) {
 	if !ok {
 		msg := e.emitter.problem
 		if msg == "" {
 			msg = "unknown problem generating YAML content"
 		}
 		failf("%s", msg)
 	}
 }
 
 func (e *encoder) marshalDoc(tag string, in reflect.Value) {
 	e.init()
 	var node *Node
 	if in.IsValid() {
 		node, _ = in.Interface().(*Node)
 	}
 	if node != nil && node.Kind == DocumentNode {
 		e.nodev(in)
 	} else {
 		yaml_document_start_event_initialize(&e.event, nil, nil, true)
 		e.emit()
 		e.marshal(tag, in)
 		yaml_document_end_event_initialize(&e.event, true)
 		e.emit()
 	}
 }
 
 func (e *encoder) marshal(tag string, in reflect.Value) {
 	tag = shortTag(tag)
 	if !in.IsValid() || in.Kind() == reflect.Ptr && in.IsNil() {
 		e.nilv()
 		return
 	}
 	iface := in.Interface()
 	switch value := iface.(type) {
 	case *Node:
 		e.nodev(in)
 		return
 	case Node:
 		if !in.CanAddr() {
 			var n = reflect.New(in.Type()).Elem()
 			n.Set(in)
 			in = n
 		}
 		e.nodev(in.Addr())
 		return
 	case time.Time:
 		e.timev(tag, in)
 		return
 	case *time.Time:
 		e.timev(tag, in.Elem())
 		return
 	case time.Duration:
 		e.stringv(tag, reflect.ValueOf(value.String()))
 		return
 	case Marshaler:
 		v, err := value.MarshalYAML()
 		if err != nil {
 			fail(err)
 		}
 		if v == nil {
 			e.nilv()
 			return
 		}
 		e.marshal(tag, reflect.ValueOf(v))
 		return
 	case encoding.TextMarshaler:
 		text, err := value.MarshalText()
 		if err != nil {
 			fail(err)
 		}
 		in = reflect.ValueOf(string(text))
 	case nil:
 		e.nilv()
 		return
 	}
 	switch in.Kind() {
 	case reflect.Interface:
 		e.marshal(tag, in.Elem())
 	case reflect.Map:
 		e.mapv(tag, in)
 	case reflect.Ptr:
 		e.marshal(tag, in.Elem())
 	case reflect.Struct:
 		e.structv(tag, in)
 	case reflect.Slice, reflect.Array:
 		e.slicev(tag, in)
 	case reflect.String:
 		e.stringv(tag, in)
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		e.intv(tag, in)
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 		e.uintv(tag, in)
 	case reflect.Float32, reflect.Float64:
 		e.floatv(tag, in)
 	case reflect.Bool:
 		e.boolv(tag, in)
 	default:
 		panic("cannot marshal type: " + in.Type().String())
 	}
 }
 
 func (e *encoder) mapv(tag string, in reflect.Value) {
 	e.mappingv(tag, func() {
 		keys := keyList(in.MapKeys())
 		sort.Sort(keys)
 		for _, k := range keys {
 			e.marshal("", k)
 			e.marshal("", in.MapIndex(k))
 		}
 	})
 }
 
 func (e *encoder) fieldByIndex(v reflect.Value, index []int) (field reflect.Value) {
 	for _, num := range index {
 		for {
 			if v.Kind() == reflect.Ptr {
 				if v.IsNil() {
 					return reflect.Value{}
 				}
 				v = v.Elem()
 				continue
 			}
 			break
 		}
 		v = v.Field(num)
 	}
 	return v
 }
 
 func (e *encoder) structv(tag string, in reflect.Value) {
 	sinfo, err := getStructInfo(in.Type())
 	if err != nil {
 		panic(err)
 	}
 	e.mappingv(tag, func() {
 		for _, info := range sinfo.FieldsList {
 			var value reflect.Value
 			if info.Inline == nil {
 				value = in.Field(info.Num)
 			} else {
 				value = e.fieldByIndex(in, info.Inline)
 				if !value.IsValid() {
 					continue
 				}
 			}
 			if info.OmitEmpty && isZero(value) {
 				continue
 			}
 			e.marshal("", reflect.ValueOf(info.Key))
 			e.flow = info.Flow
 			e.marshal("", value)
 		}
 		if sinfo.InlineMap >= 0 {
 			m := in.Field(sinfo.InlineMap)
 			if m.Len() > 0 {
 				e.flow = false
 				keys := keyList(m.MapKeys())
 				sort.Sort(keys)
 				for _, k := range keys {
 					if _, found := sinfo.FieldsMap[k.String()]; found {
 						panic(fmt.Sprintf("cannot have key %q in inlined map: conflicts with struct field", k.String()))
 					}
 					e.marshal("", k)
 					e.flow = false
 					e.marshal("", m.MapIndex(k))
 				}
 			}
 		}
 	})
 }
 
 func (e *encoder) mappingv(tag string, f func()) {
 	implicit := tag == ""
 	style := yaml_BLOCK_MAPPING_STYLE
 	if e.flow {
 		e.flow = false
 		style = yaml_FLOW_MAPPING_STYLE
 	}
 	yaml_mapping_start_event_initialize(&e.event, nil, []byte(tag), implicit, style)
 	e.emit()
 	f()
 	yaml_mapping_end_event_initialize(&e.event)
 	e.emit()
 }
 
 func (e *encoder) slicev(tag string, in reflect.Value) {
 	implicit := tag == ""
 	style := yaml_BLOCK_SEQUENCE_STYLE
 	if e.flow {
 		e.flow = false
 		style = yaml_FLOW_SEQUENCE_STYLE
 	}
 	e.must(yaml_sequence_start_event_initialize(&e.event, nil, []byte(tag), implicit, style))
 	e.emit()
 	n := in.Len()
 	for i := 0; i < n; i++ {
 		e.marshal("", in.Index(i))
 	}
 	e.must(yaml_sequence_end_event_initialize(&e.event))
 	e.emit()
 }
 
 // isBase60 returns whether s is in base 60 notation as defined in YAML 1.1.
 //
 // The base 60 float notation in YAML 1.1 is a terrible idea and is unsupported
 // in YAML 1.2 and by this package, but these should be marshalled quoted for
 // the time being for compatibility with other parsers.
 func isBase60Float(s string) (result bool) {
 	// Fast path.
 	if s == "" {
 		return false
 	}
 	c := s[0]
 	if !(c == '+' || c == '-' || c >= '0' && c <= '9') || strings.IndexByte(s, ':') < 0 {
 		return false
 	}
 	// Do the full match.
 	return base60float.MatchString(s)
 }
 
 // From http://yaml.org/type/float.html, except the regular expression there
 // is bogus. In practice parsers do not enforce the "\.[0-9_]*" suffix.
 var base60float = regexp.MustCompile(`^[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+(?:\.[0-9_]*)?$`)
 
 // isOldBool returns whether s is bool notation as defined in YAML 1.1.
 //
 // We continue to force strings that YAML 1.1 would interpret as booleans to be
 // rendered as quotes strings so that the marshalled output valid for YAML 1.1
 // parsing.
 func isOldBool(s string) (result bool) {
 	switch s {
 	case "y", "Y", "yes", "Yes", "YES", "on", "On", "ON",
 		"n", "N", "no", "No", "NO", "off", "Off", "OFF":
 		return true
 	default:
 		return false
 	}
 }
 
 func (e *encoder) stringv(tag string, in reflect.Value) {
 	var style yaml_scalar_style_t
 	s := in.String()
 	canUsePlain := true
 	switch {
 	case !utf8.ValidString(s):
 		if tag == binaryTag {
 			failf("explicitly tagged !!binary data must be base64-encoded")
 		}
 		if tag != "" {
 			failf("cannot marshal invalid UTF-8 data as %s", shortTag(tag))
 		}
 		// It can't be encoded directly as YAML so use a binary tag
 		// and encode it as base64.
 		tag = binaryTag
 		s = encodeBase64(s)
 	case tag == "":
 		// Check to see if it would resolve to a specific
 		// tag when encoded unquoted. If it doesn't,
 		// there's no need to quote it.
 		rtag, _ := resolve("", s)
 		canUsePlain = rtag == strTag && !(isBase60Float(s) || isOldBool(s))
 	}
 	// Note: it's possible for user code to emit invalid YAML
 	// if they explicitly specify a tag and a string containing
 	// text that's incompatible with that tag.
 	switch {
 	case strings.Contains(s, "\n"):
 		if e.flow {
 			style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
 		} else {
 			style = yaml_LITERAL_SCALAR_STYLE
 		}
 	case canUsePlain:
 		style = yaml_PLAIN_SCALAR_STYLE
 	default:
 		style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
 	}
 	e.emitScalar(s, "", tag, style, nil, nil, nil, nil)
 }
 
 func (e *encoder) boolv(tag string, in reflect.Value) {
 	var s string
 	if in.Bool() {
 		s = "true"
 	} else {
 		s = "false"
 	}
 	e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE, nil, nil, nil, nil)
 }
 
 func (e *encoder) intv(tag string, in reflect.Value) {
 	s := strconv.FormatInt(in.Int(), 10)
 	e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE, nil, nil, nil, nil)
 }
 
 func (e *encoder) uintv(tag string, in reflect.Value) {
 	s := strconv.FormatUint(in.Uint(), 10)
 	e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE, nil, nil, nil, nil)
 }
 
 func (e *encoder) timev(tag string, in reflect.Value) {
 	t := in.Interface().(time.Time)
 	s := t.Format(time.RFC3339Nano)
 	e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE, nil, nil, nil, nil)
 }
 
 func (e *encoder) floatv(tag string, in reflect.Value) {
 	// Issue #352: When formatting, use the precision of the underlying value
 	precision := 64
 	if in.Kind() == reflect.Float32 {
 		precision = 32
 	}
 
 	s := strconv.FormatFloat(in.Float(), 'g', -1, precision)
 	switch s {
 	case "+Inf":
 		s = ".inf"
 	case "-Inf":
 		s = "-.inf"
 	case "NaN":
 		s = ".nan"
 	}
 	e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE, nil, nil, nil, nil)
 }
 
 func (e *encoder) nilv() {
 	e.emitScalar("null", "", "", yaml_PLAIN_SCALAR_STYLE, nil, nil, nil, nil)
 }
 
 func (e *encoder) emitScalar(value, anchor, tag string, style yaml_scalar_style_t, head, line, foot, tail []byte) {
 	// TODO Kill this function. Replace all initialize calls by their underlining Go literals.
 	implicit := tag == ""
 	if !implicit {
 		tag = longTag(tag)
 	}
 	e.must(yaml_scalar_event_initialize(&e.event, []byte(anchor), []byte(tag), []byte(value), implicit, implicit, style))
 	e.event.head_comment = head
 	e.event.line_comment = line
 	e.event.foot_comment = foot
 	e.event.tail_comment = tail
 	e.emit()
 }
 
 func (e *encoder) nodev(in reflect.Value) {
 	e.node(in.Interface().(*Node), "")
 }
 
 func (e *encoder) node(node *Node, tail string) {
 	// Zero nodes behave as nil.
 	if node.Kind == 0 && node.IsZero() {
 		e.nilv()
 		return
 	}
 
 	// If the tag was not explicitly requested, and dropping it won't change the
 	// implicit tag of the value, don't include it in the presentation.
 	var tag = node.Tag
 	var stag = shortTag(tag)
 	var forceQuoting bool
 	if tag != "" && node.Style&TaggedStyle == 0 {
 		if node.Kind == ScalarNode {
 			if stag == strTag && node.Style&(SingleQuotedStyle|DoubleQuotedStyle|LiteralStyle|FoldedStyle) != 0 {
 				tag = ""
 			} else {
 				rtag, _ := resolve("", node.Value)
 				if rtag == stag {
 					tag = ""
 				} else if stag == strTag {
 					tag = ""
 					forceQuoting = true
 				}
 			}
 		} else {
 			var rtag string
 			switch node.Kind {
 			case MappingNode:
 				rtag = mapTag
 			case SequenceNode:
 				rtag = seqTag
 			}
 			if rtag == stag {
 				tag = ""
 			}
 		}
 	}
 
 	switch node.Kind {
 	case DocumentNode:
 		yaml_document_start_event_initialize(&e.event, nil, nil, true)
 		e.event.head_comment = []byte(node.HeadComment)
 		e.emit()
 		for _, node := range node.Content {
 			e.node(node, "")
 		}
 		yaml_document_end_event_initialize(&e.event, true)
 		e.event.foot_comment = []byte(node.FootComment)
 		e.emit()
 
 	case SequenceNode:
 		style := yaml_BLOCK_SEQUENCE_STYLE
 		if node.Style&FlowStyle != 0 {
 			style = yaml_FLOW_SEQUENCE_STYLE
 		}
 		e.must(yaml_sequence_start_event_initialize(&e.event, []byte(node.Anchor), []byte(longTag(tag)), tag == "", style))
 		e.event.head_comment = []byte(node.HeadComment)
 		e.emit()
 		for _, node := range node.Content {
 			e.node(node, "")
 		}
 		e.must(yaml_sequence_end_event_initialize(&e.event))
 		e.event.line_comment = []byte(node.LineComment)
 		e.event.foot_comment = []byte(node.FootComment)
 		e.emit()
 
 	case MappingNode:
 		style := yaml_BLOCK_MAPPING_STYLE
 		if node.Style&FlowStyle != 0 {
 			style = yaml_FLOW_MAPPING_STYLE
 		}
 		yaml_mapping_start_event_initialize(&e.event, []byte(node.Anchor), []byte(longTag(tag)), tag == "", style)
 		e.event.tail_comment = []byte(tail)
 		e.event.head_comment = []byte(node.HeadComment)
 		e.emit()
 
 		// The tail logic below moves the foot comment of prior keys to the following key,
 		// since the value for each key may be a nested structure and the foot needs to be
 		// processed only the entirety of the value is streamed. The last tail is processed
 		// with the mapping end event.
 		var tail string
 		for i := 0; i+1 < len(node.Content); i += 2 {
 			k := node.Content[i]
 			foot := k.FootComment
 			if foot != "" {
 				kopy := *k
 				kopy.FootComment = ""
 				k = &kopy
 			}
 			e.node(k, tail)
 			tail = foot
 
 			v := node.Content[i+1]
 			e.node(v, "")
 		}
 
 		yaml_mapping_end_event_initialize(&e.event)
 		e.event.tail_comment = []byte(tail)
 		e.event.line_comment = []byte(node.LineComment)
 		e.event.foot_comment = []byte(node.FootComment)
 		e.emit()
 
 	case AliasNode:
 		yaml_alias_event_initialize(&e.event, []byte(node.Value))
 		e.event.head_comment = []byte(node.HeadComment)
 		e.event.line_comment = []byte(node.LineComment)
 		e.event.foot_comment = []byte(node.FootComment)
 		e.emit()
 
 	case ScalarNode:
 		value := node.Value
 		if !utf8.ValidString(value) {
 			if stag == binaryTag {
 				failf("explicitly tagged !!binary data must be base64-encoded")
 			}
 			if stag != "" {
 				failf("cannot marshal invalid UTF-8 data as %s", stag)
 			}
 			// It can't be encoded directly as YAML so use a binary tag
 			// and encode it as base64.
 			tag = binaryTag
 			value = encodeBase64(value)
 		}
 
 		style := yaml_PLAIN_SCALAR_STYLE
 		switch {
 		case node.Style&DoubleQuotedStyle != 0:
 			style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
 		case node.Style&SingleQuotedStyle != 0:
 			style = yaml_SINGLE_QUOTED_SCALAR_STYLE
 		case node.Style&LiteralStyle != 0:
 			style = yaml_LITERAL_SCALAR_STYLE
 		case node.Style&FoldedStyle != 0:
 			style = yaml_FOLDED_SCALAR_STYLE
 		case strings.Contains(value, "\n"):
 			style = yaml_LITERAL_SCALAR_STYLE
 		case forceQuoting:
 			style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
 		}
 
 		e.emitScalar(value, node.Anchor, tag, style, []byte(node.HeadComment), []byte(node.LineComment), []byte(node.FootComment), []byte(tail))
 	default:
 		failf("cannot encode node with unknown kind %d", node.Kind)
 	}
 }