Init

internal/hscan/structmap.go

@@ -0,0 +1,125 @@
+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.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
+}