/
reflect.go
348 lines (294 loc) · 9.57 KB
/
reflect.go
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package com
import (
"errors"
"fmt"
"github.com/seago/logger"
"reflect"
"runtime/debug"
"unicode"
)
func IsExportedName(name string) bool {
return name != "" && unicode.IsUpper(rune(name[0]))
}
func IsExportedField(structField reflect.StructField) bool {
return structField.PkgPath == ""
}
// CopyExportedStructFields copies all exported struct fields from src
// that are assignable to their name siblings at dstPtr to dstPtr.
// src can be a struct or a pointer to a struct, dstPtr must be
// a pointer to a struct.
func CopyExportedStructFields(src, dstPtr interface{}) (copied int) {
vsrc := reflect.ValueOf(src)
if vsrc.Kind() == reflect.Ptr {
vsrc = vsrc.Elem()
}
vdst := reflect.ValueOf(dstPtr).Elem()
return CopyExportedStructFieldsVal(vsrc, vdst)
}
func ExportedStructFields(v reflect.Value) map[string]reflect.Value {
t := v.Type()
if t.Kind() != reflect.Struct {
panic(fmt.Errorf("Expected a struct, got %s", t))
}
result := make(map[string]reflect.Value)
exportedStructFields(v, t, result)
return result
}
func exportedStructFields(v reflect.Value, t reflect.Type, result map[string]reflect.Value) {
for i := 0; i < t.NumField(); i++ {
structField := t.Field(i)
if IsExportedField(structField) {
if structField.Anonymous && structField.Type.Kind() == reflect.Struct {
exportedStructFields(v.Field(i), structField.Type, result)
} else {
result[structField.Name] = v.Field(i)
}
}
}
}
func CopyExportedStructFieldsVal(src, dst reflect.Value) (copied int) {
if src.Kind() != reflect.Struct {
panic(fmt.Errorf("CopyExportedStructFieldsVal: src must be struct, got %s", src.Type()))
}
if dst.Kind() != reflect.Struct {
panic(fmt.Errorf("CopyExportedStructFieldsVal: dst must be struct, got %s", dst.Type()))
}
if !dst.CanSet() {
panic(fmt.Errorf("CopyExportedStructFieldsVal: dst (%s) is not set-able", dst.Type()))
}
srcFields := ExportedStructFields(src)
dstFields := ExportedStructFields(dst)
for name, srcV := range srcFields {
if dstV, ok := dstFields[name]; ok {
if srcV.Type().AssignableTo(dstV.Type()) {
dstV.Set(srcV)
copied++
}
}
}
return copied
}
func IsEmptyValue(v interface{}) bool {
reflectValue := reflect.ValueOf(v)
if reflectValue.Kind() == reflect.Ptr {
reflectValue = reflectValue.Elem()
}
return isEmptyValue(reflectValue)
}
func isEmptyValue(v reflect.Value) bool {
switch v.Kind() {
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
return v.Len() == 0
case reflect.Bool:
return !v.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return v.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return v.Uint() == 0
case reflect.Float32, reflect.Float64:
return v.Float() == 0
case reflect.Interface, reflect.Ptr:
return v.IsNil()
}
return false
}
func Invoke(any interface{}, name string, args ...interface{}) (result []reflect.Value) {
defer func() {
if err := recover(); err != nil {
logger.Error("Painc error : %v", err)
trackBack := string(debug.Stack())
logger.Error(trackBack)
result = append(result, reflect.ValueOf(err))
}
}()
inputs := make([]reflect.Value, len(args))
for i, _ := range args {
inputs[i] = reflect.ValueOf(args[i])
}
result = reflect.ValueOf(any).MethodByName(name).Call(inputs)
return
}
func GetMethods(v interface{}) map[string][]string {
funcMap := make(map[string][]string)
reflectType := reflect.TypeOf(v)
//reflectkind := reflectType.Kind()
// if reflectkind == reflect.Ptr {
// reflectType = reflectType.Elem()
// }
for i := 0; i < reflectType.NumMethod(); i++ {
funcList := make([]string, 0)
method := reflectType.Method(i)
methodType := method.Type
methodName := method.Name
if !IsExportedName(methodName) {
continue
}
for j := 1; j < methodType.NumIn(); j++ {
params := methodType.In(j)
funcList = append(funcList, params.Name())
}
funcMap[methodName] = funcList
}
logger.Debug("GetMethods:%v", funcMap)
return funcMap
}
// GetField returns the value of the provided obj field. obj can whether
// be a structure or pointer to structure.
func GetField(obj interface{}, name string) (interface{}, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return nil, errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
field := objValue.FieldByName(name)
if !field.IsValid() {
return nil, fmt.Errorf("No such field: %s in obj", name)
}
return field.Interface(), nil
}
// GetFieldKind returns the kind of the provided obj field. obj can whether
// be a structure or pointer to structure.
func GetFieldKind(obj interface{}, name string) (reflect.Kind, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return reflect.Invalid, errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
field := objValue.FieldByName(name)
if !field.IsValid() {
return reflect.Invalid, fmt.Errorf("No such field: %s in obj", name)
}
return field.Type().Kind(), nil
}
// GetFieldTag returns the provided obj field tag value. obj can whether
// be a structure or pointer to structure.
func GetFieldTag(obj interface{}, fieldName, tagKey string) (string, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return "", errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
objType := objValue.Type()
field, ok := objType.FieldByName(fieldName)
if !ok {
return "", fmt.Errorf("No such field: %s in obj", fieldName)
}
if !IsExportedField(field) {
return "", errors.New("Cannot GetFieldTag on a non-exported struct field")
}
return field.Tag.Get(tagKey), nil
}
// SetField sets the provided obj field with provided value. obj param has
// to be a pointer to a struct, otherwise it will soundly fail. Provided
// value type should match with the struct field you're trying to set.
func SetField(obj interface{}, name string, value interface{}) error {
// Fetch the field reflect.Value
structValue := reflect.ValueOf(obj).Elem()
structFieldValue := structValue.FieldByName(name)
if !structFieldValue.IsValid() {
return fmt.Errorf("No such field: %s in obj", name)
}
// If obj field value is not settable an error is thrown
if !structFieldValue.CanSet() {
return fmt.Errorf("Cannot set %s field value", name)
}
structFieldType := structFieldValue.Type()
val := reflect.ValueOf(value)
if structFieldType != val.Type() {
invalidTypeError := errors.New("Provided value type didn't match obj field type")
return invalidTypeError
}
structFieldValue.Set(val)
return nil
}
// HasField checks if the provided field name is part of a struct. obj can whether
// be a structure or pointer to structure.
func HasField(obj interface{}, name string) (bool, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return false, errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
objType := objValue.Type()
field, ok := objType.FieldByName(name)
if !ok || !IsExportedField(field) {
return false, nil
}
return true, nil
}
// Fields returns the struct fields names list. obj can whether
// be a structure or pointer to structure.
func Fields(obj interface{}) ([]string, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return nil, errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
objType := objValue.Type()
fieldsCount := objType.NumField()
var fields []string
for i := 0; i < fieldsCount; i++ {
field := objType.Field(i)
if IsExportedField(field) {
fields = append(fields, field.Name)
}
}
return fields, nil
}
// Items returns the field - value struct pairs as a map. obj can whether
// be a structure or pointer to structure.
func Items(obj interface{}) (map[string]interface{}, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return nil, errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
objType := objValue.Type()
fieldsCount := objType.NumField()
items := make(map[string]interface{})
for i := 0; i < fieldsCount; i++ {
field := objType.Field(i)
fieldValue := objValue.Field(i)
// Make sure only exportable and addressable fields are
// returned by Items
if IsExportedField(field) {
items[field.Name] = fieldValue.Interface()
}
}
return items, nil
}
// Tags lists the struct tag fields. obj can whether
// be a structure or pointer to structure.
func Tags(obj interface{}, key string) (map[string]string, error) {
if !hasValidType(obj, []reflect.Kind{reflect.Struct, reflect.Ptr}) {
return nil, errors.New("Cannot use GetField on a non-struct interface")
}
objValue := reflectValue(obj)
objType := objValue.Type()
fieldsCount := objType.NumField()
tags := make(map[string]string)
for i := 0; i < fieldsCount; i++ {
structField := objType.Field(i)
if IsExportedField(structField) {
tags[structField.Name] = structField.Tag.Get(key)
}
}
return tags, nil
}
func reflectValue(obj interface{}) reflect.Value {
var val reflect.Value
if reflect.TypeOf(obj).Kind() == reflect.Ptr {
val = reflect.ValueOf(obj).Elem()
} else {
val = reflect.ValueOf(obj)
}
return val
}
func hasValidType(obj interface{}, types []reflect.Kind) bool {
for _, t := range types {
if reflect.TypeOf(obj).Kind() == t {
return true
}
}
return false
}
func isStruct(obj interface{}) bool {
return reflect.TypeOf(obj).Kind() == reflect.Struct
}
func isPointer(obj interface{}) bool {
return reflect.TypeOf(obj).Kind() == reflect.Ptr
}