annotation-go/registry.go

package annotation

import (
	"encoding/json"
	"fmt"
	"reflect"
	"strings"

	cur "git.loafle.net/commons/util-go/reflect"
)

type Registry interface {
	Register(t reflect.Type) error
	Get(f *reflect.StructField) (map[reflect.Type]Annotation, error)
}

var SystemRegistry = &AnnotationRegistry{
	parent:      nil,
	definitions: make(map[string]*Definition, 0),
}

func New(parent Registry) Registry {
	r := &AnnotationRegistry{
		parent:      parent,
		definitions: make(map[string]*Definition, 0),
	}
	if nil == r.parent {
		r.parent = SystemRegistry
	}
	return r
}

type AnnotationRegistry struct {
	parent      Registry
	definitions map[string]*Definition
}

func Register(t reflect.Type) error {
	return SystemRegistry.Register(t)
}
func (r *AnnotationRegistry) Register(t reflect.Type) error {
	rt, _, _ := cur.GetTypeInfo(t)

	fields := findAnnotatedFields(t, AnnotationType, false)
	switch len(fields) {
	case 0:
		return fmt.Errorf("type[%s] is not Annotation", rt.Name())
	case 1:
	default:
		return fmt.Errorf("type[%s] have only one Annotation", rt.Name())
	}

	f := fields[AnnotationName]
	name := strings.TrimSpace(f.Tag.Get(NameTag))
	if "" == name {
		return fmt.Errorf("annotation name of type[%s] is not valid", rt.Name())
	}

	if _, ok := r.definitions[name]; ok {
		return fmt.Errorf("name[%s] of annotation exist already", name)
	}

	r.definitions[name] = &Definition{
		t:  t,
		rt: rt,
	}

	return nil
}

func Get(f *reflect.StructField) (map[reflect.Type]Annotation, error) {
	return SystemRegistry.Get(f)
}
func (r *AnnotationRegistry) Get(f *reflect.StructField) (map[reflect.Type]Annotation, error) {
	annotations := make(map[reflect.Type]Annotation, 0)

	tag := strings.TrimSpace(f.Tag.Get(AnnotationTag))
	if "" == tag {
		return annotations, nil
	}

	if !AnnotationRGX.MatchString(tag) {
		return nil, fmt.Errorf("Tag of annotation[%s] is not match", tag)
	}

	rss := AnnotationRGX.FindAllStringSubmatch(tag, -1)
	if nil == rss || 0 == len(rss) {
		return annotations, nil
	}

	for _, rs := range rss {
		if 3 != len(rs) {
			return nil, fmt.Errorf("Tag of annotation[%s] is not valid", rs[0])
		}

		name := fmt.Sprintf("@%s", strings.TrimSpace(rs[1]))
		body := rs[2]

		if !AnnotationBodyRGX.MatchString(body) {
			return nil, fmt.Errorf("Body[%s] of annotation[%s] is not valid", body, name)
		}

		body = AnnotationBodyRGX.ReplaceAllStringFunc(body, func(token string) string {
			switch len(token) {
			case 0, 1, 2:
				return "\"\""
			default:
				return strings.Replace(fmt.Sprintf("\"%s\"", token[1:len(token)-1]), "\\'", "'", -1)
			}
		})
		body = fmt.Sprintf("{%s}", strings.TrimSpace(body))

		def, ok := r.definitions[name]
		if !ok {
			return nil, fmt.Errorf("annotation[%s] is not exist", name)
		}

		v := reflect.New(def.rt)
		i := v.Interface()

		err := json.Unmarshal([]byte(body), i)
		if nil != err {
			return nil, fmt.Errorf("Unmarshal failed %v", err)
		}

		annotations[def.t] = i
	}

	return annotations, nil
}

func findAnnotatedFields(t reflect.Type, ft reflect.Type, deep bool) map[string]*reflect.StructField {
	fields := make(map[string]*reflect.StructField, 0)

	rt, _, _ := cur.GetTypeInfo(t)
	if reflect.Struct != rt.Kind() {
		return fields
	}

LOOP:
	for i := 0; i < rt.NumField(); i++ {
		f := rt.Field(i)

		if f.Anonymous {
			if f.Type == ft {
				fields[f.Name] = &f
				continue LOOP
			}
			if deep {
				_fields := findAnnotatedFields(f.Type, ft, deep)
				for _n, _f := range _fields {
					fields[_n] = _f
				}
			}
		}
	}
	return fields
}

var InjectableAnnotationType = reflect.TypeOf((*InjectableAnnotation)(nil))

type InjectableAnnotation struct {
	Annotation `@name:"@Component"`
	Name       string `json:"name" @default:"test"`
}