redis/internal/hscan/structmap.go

128 lines
2.6 KiB
Go

package hscan
import (
"encoding"
"fmt"
"reflect"
"strings"
"sync"
"github.com/redis/go-redis/v9/internal/util"
)
// structMap contains the map of struct fields for target structs
// indexed by the struct type.
type structMap struct {
m sync.Map
}
func newStructMap() *structMap {
return new(structMap)
}
func (s *structMap) get(t reflect.Type) *structSpec {
if v, ok := s.m.Load(t); ok {
return v.(*structSpec)
}
spec := newStructSpec(t, "redis")
s.m.Store(t, spec)
return spec
}
//------------------------------------------------------------------------------
// structSpec contains the list of all fields in a target struct.
type structSpec struct {
m map[string]*structField
}
func (s *structSpec) set(tag string, sf *structField) {
s.m[tag] = sf
}
func newStructSpec(t reflect.Type, fieldTag string) *structSpec {
numField := t.NumField()
out := &structSpec{
m: make(map[string]*structField, numField),
}
for i := 0; i < numField; i++ {
f := t.Field(i)
tag := f.Tag.Get(fieldTag)
if tag == "" || tag == "-" {
continue
}
tag = strings.Split(tag, ",")[0]
if tag == "" {
continue
}
// Use the built-in decoder.
kind := f.Type.Kind()
if kind == reflect.Pointer {
kind = f.Type.Elem().Kind()
}
out.set(tag, &structField{index: i, fn: decoders[kind]})
}
return out
}
//------------------------------------------------------------------------------
// structField represents a single field in a target struct.
type structField struct {
index int
fn decoderFunc
}
//------------------------------------------------------------------------------
type StructValue struct {
spec *structSpec
value reflect.Value
}
func (s StructValue) Scan(key string, value string) error {
field, ok := s.spec.m[key]
if !ok {
return nil
}
v := s.value.Field(field.index)
isPtr := v.Kind() == reflect.Ptr
if isPtr && v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
if !isPtr && v.Type().Name() != "" && v.CanAddr() {
v = v.Addr()
isPtr = true
}
if isPtr && v.Type().NumMethod() > 0 && v.CanInterface() {
switch scan := v.Interface().(type) {
case Scanner:
return scan.ScanRedis(value)
case encoding.BinaryUnmarshaler:
return scan.UnmarshalBinary(util.StringToBytes(value))
case encoding.TextUnmarshaler:
return scan.UnmarshalText(util.StringToBytes(value))
}
}
if isPtr {
v = v.Elem()
}
if err := field.fn(v, value); err != nil {
t := s.value.Type()
return fmt.Errorf("cannot scan redis.result %s into struct field %s.%s of type %s, error-%s",
value, t.Name(), t.Field(field.index).Name, t.Field(field.index).Type, err.Error())
}
return nil
}