go/packs/js/kv_packer.go

// ------------------------------------------------------------------------
//   Project atila
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  key_val_packer.go
//   Created by DEV
//   Modified   03/02/2024
//
//   Copyright 2024 activething.com 
// ------------------------------------------------------------------------
// 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 js

import (
	"activething.com/go/gogo/packs"
	"encoding"
	"reflect"
	"sort"
	"strconv"
)

type (

	kvPacker 	struct {
		keyFn   keyStringerFnc
		valFn   packerFn
	}

	keyStringerFnc func(entry *kvEntry, rkey reflect.Value) error

)



func newKVPacker (rtype reflect.Type) *kvPacker {
	return &kvPacker{
		valFn  : typePacker(rtype.Elem()),
		keyFn  : _keyStringer(rtype.Key()),
	}
}



func (p *kvPacker) pack (s *packs.State, v reflect.Value, f Flags) {
	if p.keyFn == nil {
		s.SetError(packs.G.ErrInvalidKey)
		return 
	}
	
	if v.IsNil() {
		s.W(G.nullValue)
		return
	}
	if v.Len() == 0{
		s.Write2Byte('{','}')
		return
	}

	if s.Level > startDetectingCyclesAfter {
		if fn,ok := s.CheckCycle(v.UnsafePointer()); ok {
			defer fn()
		} else {
			s.SetError(packs.G.ErrRedundantPack)
			return
		}
	}

	mi := v.MapRange()
	ls := make(kvEntryList,v.Len())

	for i:=0; mi.Next(); i++ {
		ls[i] = kvEntry {
			rval: mi.Value(),
		}
		if er := p.keyFn(&ls[i], mi.Key()); er != nil {
			s.SetError(er)
			return
		}
	}

	sort.Sort(ls)

	s.Open ('{')
	for i:=0; i<len(ls); i++ {
		if i>0 {
			s.WriteByte(',')
		}
		packString(s,ls[i].key,ls[i].flags)
		if s.Error != nil {
			return
		}
		s.WriteByte(':')
		p.valFn(s,ls[i].rval,0)
		if s.Error != nil {
			return
		}
	}
	s.Close('}')
}




func _keyStringer(rt reflect.Type) func(me *kvEntry, key reflect.Value) error {
	if rt.Kind() == reflect.String {
		return func(e *kvEntry, k reflect.Value) error {
			e.key = k.String()
			e.flags = FlagScapeHTML
			return nil
		}
	}

	if rt.Implements(reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()) {
		return func(e *kvEntry, k reflect.Value) error {
			if k.Kind() == reflect.Pointer && k.IsNil() {
				return nil
			}
			bf, er := (k.Interface().(encoding.TextMarshaler)).MarshalText()
			if er == nil {
				e.key = string(bf)
				e.flags = FlagScapeHTML
			}
			return er
		}
	}

	switch rt.Kind() {

	case reflect.Int,
		reflect.Int8,
		reflect.Int16,
		reflect.Int32,
		reflect.Int64:
		return func(e *kvEntry, k reflect.Value) error {
			e.key = strconv.FormatInt(k.Int(), 10)
			return nil
		}
	case reflect.Uint,
		reflect.Uint8,
		reflect.Uint16,
		reflect.Uint32,
		reflect.Uint64,
		reflect.Uintptr:
		return func(e *kvEntry, k reflect.Value) error {
			e.key = strconv.FormatUint(k.Uint(), 10)
			return nil
		}

	case reflect.Interface:
		return func(e *kvEntry, k reflect.Value) error {
			k = k.Elem()

			if k.Type().Kind() == reflect.String {
				e.key = k.String()
				e.flags = FlagScapeHTML
				return nil
			}

			if t,h := k.Interface().(encoding.TextMarshaler); h {
				if k.Type().Kind() == reflect.Pointer && k.IsNil() {
					return nil
				}
				bf, er := t.MarshalText()
				if er == nil {
					e.key = string(bf)
					e.flags = FlagScapeHTML
				}
				return er
			}

			switch rt.Kind() {

			case reflect.Int,
				reflect.Int8,
				reflect.Int16,
				reflect.Int32,
				reflect.Int64:
				e.key = strconv.FormatInt(k.Int(), 10)
				return nil

			case reflect.Uint,
				reflect.Uint8,
				reflect.Uint16,
				reflect.Uint32,
				reflect.Uint64,
				reflect.Uintptr:
				e.key = strconv.FormatUint(k.Uint(), 10)
				return nil

			default:
				return packs.G.ErrInvalidKey
			}
		}

	default:
		return nil
	}


}