Golang reflect.Append函数代码示例

func (p *partitioner) partitionate(val, idx_or_key reflect.Value) {
	if ok := callPredicate(p.fn, val, idx_or_key); ok {
		p.t = reflect.Append(p.t, val)
	} else {
		p.f = reflect.Append(p.f, val)
	}
}

// Remove duplicate element of a slice.
// If error occurs, return value of r will be nil.
func UniqueWithError(s interface{}) (r interface{}, err error) {

	v := reflect.ValueOf(s)

	if v.Kind() != reflect.Slice {
		err = fmt.Errorf("Parameter a must be a slice.")
		return
	}

	rest := reflect.MakeSlice(reflect.TypeOf(s), 0, 0)

	for i := v.Len() - 1; i >= 0; i-- {
		current := reflect.ValueOf(s).Slice(0, i)

		exist, e := InWithError(current.Interface(), v.Index(i).Interface())
		if e != nil {
			err = e
			return
		}
		if !exist {
			rest = reflect.Append(rest, v.Index(i))
		}
		s = current.Interface()
	}

	n := reflect.ValueOf(s)
	for i := rest.Len() - 1; i >= 0; i-- {
		n = reflect.Append(n, rest.Index(i))
	}

	r = n.Interface()

	return
}

func (scope *Scope) getColumnAsScope(column string) *Scope {
	indirectScopeValue := scope.IndirectValue()

	switch indirectScopeValue.Kind() {
	case reflect.Slice:
		if fieldStruct, ok := scope.GetModelStruct().ModelType.FieldByName(column); ok {
			fieldType := fieldStruct.Type
			if fieldType.Kind() == reflect.Slice || fieldType.Kind() == reflect.Ptr {
				fieldType = fieldType.Elem()
			}

			results := reflect.New(reflect.SliceOf(reflect.PtrTo(fieldType))).Elem()

			for i := 0; i < indirectScopeValue.Len(); i++ {
				result := indirect(indirect(indirectScopeValue.Index(i)).FieldByName(column))

				if result.Kind() == reflect.Slice {
					for j := 0; j < result.Len(); j++ {
						if elem := result.Index(j); elem.CanAddr() {
							results = reflect.Append(results, elem.Addr())
						}
					}
				} else if result.CanAddr() {
					results = reflect.Append(results, result.Addr())
				}
			}
			return scope.New(results.Interface())
		}
	case reflect.Struct:
		if field := indirectScopeValue.FieldByName(column); field.CanAddr() {
			return scope.New(field.Addr().Interface())
		}
	}
	return nil
}

func (association *Association) Append(values ...interface{}) *Association {
	scope := association.Scope
	field := scope.IndirectValue().FieldByName(association.Column)
	for _, value := range values {
		reflectvalue := reflect.ValueOf(value)
		if reflectvalue.Kind() == reflect.Ptr {
			if reflectvalue.Elem().Kind() == reflect.Struct {
				if field.Type().Elem().Kind() == reflect.Ptr {
					field.Set(reflect.Append(field, reflectvalue))
				} else if field.Type().Elem().Kind() == reflect.Struct {
					field.Set(reflect.Append(field, reflectvalue.Elem()))
				}
			} else if reflectvalue.Elem().Kind() == reflect.Slice {
				if field.Type().Elem().Kind() == reflect.Ptr {
					field.Set(reflect.AppendSlice(field, reflectvalue))
				} else if field.Type().Elem().Kind() == reflect.Struct {
					field.Set(reflect.AppendSlice(field, reflectvalue.Elem()))
				}
			}
		} else if reflectvalue.Kind() == reflect.Struct && field.Type().Elem().Kind() == reflect.Struct {
			field.Set(reflect.Append(field, reflectvalue))
		} else if reflectvalue.Kind() == reflect.Slice && field.Type().Elem() == reflectvalue.Type().Elem() {
			field.Set(reflect.AppendSlice(field, reflectvalue))
		} else {
			association.err(errors.New("invalid association type"))
		}
	}
	scope.callCallbacks(scope.db.parent.callback.updates)
	return association.err(scope.db.Error)
}

func (processor *processor) decode() (errors []error) {
	if processor.checkSkipLeft() || processor.MetaValues == nil {
		return
	}

	for _, metaValue := range processor.MetaValues.Values {
		meta := metaValue.Meta
		if meta == nil {
			continue
		}

		if processor.newRecord && !meta.HasPermission(roles.Create, processor.Context) {
			continue
		} else if !meta.HasPermission(roles.Update, processor.Context) {
			continue
		}

		if setter := meta.GetSetter(); setter != nil {
			setter(processor.Result, metaValue, processor.Context)
			continue
		}

		res := metaValue.Meta.GetResource()
		if res == nil {
			continue
		}

		field := reflect.Indirect(reflect.ValueOf(processor.Result)).FieldByName(meta.GetFieldName())
		if field.Kind() == reflect.Struct {
			value := reflect.New(field.Type())
			associationProcessor := DecodeToResource(res, value.Interface(), metaValue.MetaValues, processor.Context)
			associationProcessor.Start()
			if !associationProcessor.SkipLeft {
				field.Set(value.Elem())
			}
		} else if field.Kind() == reflect.Slice {
			var fieldType = field.Type().Elem()
			var isPtr bool
			if fieldType.Kind() == reflect.Ptr {
				fieldType = fieldType.Elem()
				isPtr = true
			}

			value := reflect.New(fieldType)
			associationProcessor := DecodeToResource(res, value.Interface(), metaValue.MetaValues, processor.Context)
			associationProcessor.Start()
			if !associationProcessor.SkipLeft {
				if !reflect.DeepEqual(reflect.Zero(fieldType).Interface(), value.Elem().Interface()) {
					if isPtr {
						field.Set(reflect.Append(field, value))
					} else {
						field.Set(reflect.Append(field, value.Elem()))
					}
				}
			}
		}
	}

	return
}

func (scope *Scope) getColumnsAsScope(column string) *Scope {
	values := scope.IndirectValue()
	switch values.Kind() {
	case reflect.Slice:
		modelType := values.Type().Elem()
		if modelType.Kind() == reflect.Ptr {
			modelType = modelType.Elem()
		}
		fieldStruct, _ := modelType.FieldByName(column)
		var columns reflect.Value
		if fieldStruct.Type.Kind() == reflect.Slice || fieldStruct.Type.Kind() == reflect.Ptr {
			columns = reflect.New(reflect.SliceOf(reflect.PtrTo(fieldStruct.Type.Elem()))).Elem()
		} else {
			columns = reflect.New(reflect.SliceOf(reflect.PtrTo(fieldStruct.Type))).Elem()
		}
		for i := 0; i < values.Len(); i++ {
			column := reflect.Indirect(values.Index(i)).FieldByName(column)
			if column.Kind() == reflect.Ptr {
				column = column.Elem()
			}
			if column.Kind() == reflect.Slice {
				for i := 0; i < column.Len(); i++ {
					columns = reflect.Append(columns, column.Index(i).Addr())
				}
			} else {
				columns = reflect.Append(columns, column.Addr())
			}
		}
		return scope.New(columns.Interface())
	case reflect.Struct:
		return scope.New(values.FieldByName(column).Addr().Interface())
	}
	return nil
}

//MultiQuery executes given query and returns slice of all the entities it returns, with their keys set.
func MultiQuery(c appengine.Context, typ reflect.Type, kind string, query *datastore.Query) (ms interface{}, err error) {
	is := reflect.MakeSlice(reflect.SliceOf(reflect.PtrTo(typ)), 0, 0)

	iter := query.Run(c)

	for {
		val := reflect.New(typ)
		var key *datastore.Key
		key, err = iter.Next(val.Interface())
		if err != nil {
			if err == datastore.Done {
				err = nil
				val.MethodByName("SetKey").Call([]reflect.Value{reflect.ValueOf(key)})
				reflect.Append(is, val)
				break
			}
			return
		}
		val.MethodByName("SetKey").Call([]reflect.Value{reflect.ValueOf(key)})
		is = reflect.Append(is, val)
	}

	ms = is.Interface()

	return
}

func (l *listSink) add(i *item) (bool, error) {
	if l.limit == 0 {
		return true, nil
	}

	if l.skip > 0 {
		l.skip--
		return false, nil
	}

	if !l.results.IsValid() {
		l.results = reflect.MakeSlice(reflect.Indirect(l.ref).Type(), 0, 0)
	}

	if l.limit > 0 {
		l.limit--
	}

	if l.idx == l.results.Len() {
		if l.isPtr {
			l.results = reflect.Append(l.results, *i.value)
		} else {
			l.results = reflect.Append(l.results, reflect.Indirect(*i.value))
		}
	}

	l.idx++

	return l.limit == 0, nil
}

// If op is Operator of "[]T", type of f must be "func(T) T2".
// And GroupBy(f) returns value of "map[T2] []T"
func (op *Op) GroupBy(f interface{}) interface{} {
	vs := reflect.ValueOf(op.Slice)
	vf := reflect.ValueOf(f)

	tf := vf.Type()
	if tf.NumIn() != 1 {
		panic("Number of Argument must be 1")
	}
	if tf.NumOut() != 1 {
		panic("Number of return value must be 1")
	}

	tif := tf.In(0)
	tof := tf.Out(0)
	if tif != vs.Type().Elem() {
		panic("Mismatch function type")
	}

	len := vs.Len()
	vom := reflect.MakeMap(reflect.MapOf(tof, vs.Type()))
	for i := 0; i < len; i++ {
		v := vs.Index(i)
		vk := vf.Call([]reflect.Value{v})[0]
		vi := vom.MapIndex(vk)
		if vi.IsValid() {
			vom.SetMapIndex(vk, reflect.Append(vi, v))
		} else {
			vom.SetMapIndex(vk, reflect.Append(reflect.MakeSlice(vs.Type(), 0, len), v))
		}
	}

	return vom.Interface()
}

func ArrayMerge(arrayData interface{}, arrayData2 interface{}, arrayOther ...interface{}) interface{} {
	arrayOther = append([]interface{}{arrayData2}, arrayOther...)
	arrayOtherMap := sliceToMap(arrayOther)

	arrayValue := reflect.ValueOf(arrayData)
	arrayType := arrayValue.Type()
	arrayLen := arrayValue.Len()
	result := reflect.MakeSlice(arrayType, 0, 0)

	for i := 0; i != arrayLen; i++ {
		singleArrayDataValue := arrayValue.Index(i)
		singleArrayDataValueInterface := singleArrayDataValue.Interface()

		isFirst, isExist := arrayOtherMap[singleArrayDataValueInterface]
		if isExist == true && isFirst == false {
			continue
		}
		result = reflect.Append(result, singleArrayDataValue)
		arrayOtherMap[singleArrayDataValueInterface] = false
	}

	for single, isFirst := range arrayOtherMap {
		if isFirst == false {
			continue
		}
		result = reflect.Append(result, reflect.ValueOf(single))
	}

	return result.Interface()
}

func _partition(values []reflect.Value) []reflect.Value {
	slice := interfaceToValue(values[0])
	fn := values[1]

	var t, f reflect.Value

	if values[0].Kind() == reflect.Interface {
		t = reflect.ValueOf(make([]interface{}, 0))
		f = reflect.ValueOf(make([]interface{}, 0))
	} else {
		t = reflect.MakeSlice(slice.Type(), 0, 0)
		f = reflect.MakeSlice(slice.Type(), 0, 0)
	}

	for i := 0; i < slice.Len(); i++ {
		e := slice.Index(i)
		r := fn.Call([]reflect.Value{e})
		if r[0].Bool() {
			t = reflect.Append(t, e)
		} else {
			f = reflect.Append(f, e)
		}
	}
	return []reflect.Value{t, f}
}

func (d *Decoder) decodeSlice(s *decodStatus, v reflect.Value, t reflect.Type, tg tag) error {
	if _, isInline := tg.Modifiers["inline"]; isInline {
		val, ok := s.GetValue(d.env)
		if !ok {
			return nil
		}
		elements := d.arrSep.Split(val, -1)
		slice := reflect.MakeSlice(t, 0, len(elements))
		for _, s := range elements {
			mv := reflect.New(t.Elem())
			err := d.decodeField(mv.Elem(), s)
			if err != nil {
				return err
			}
			slice = reflect.Append(slice, mv.Elem())
		}
		v.Set(slice)
		return nil
	}
	index := s.GetIndex()
	slice := reflect.MakeSlice(t, 0, len(index))
	for _, i := range index {
		mv := reflect.New(t.Elem())
		err := d.decodeElement(s, mv.Elem(), mv.Elem().Type(), tag{Name: strconv.Itoa(i), Modifiers: tg.Modifiers})
		if err != nil {
			return err
		}
		slice = reflect.Append(slice, mv.Elem())
	}
	v.Set(slice)
	return nil
}

//This will execute the SQL and append results to the slice.
//    var ids []uint32
//    if err := From("test").Select("id").ScanVals(&ids); err != nil{
//        panic(err.Error()
//    }
//
//i: Takes a pointer to a slice of primitive values.
func (me CrudExec) ScanVals(i interface{}) error {
	if me.err != nil {
		return me.err
	}
	val := reflect.ValueOf(i)
	if val.Kind() != reflect.Ptr {
		return NewGoquError("Type must be a pointer to a slice when calling ScanVals")
	}
	val = reflect.Indirect(val)
	if val.Kind() != reflect.Slice {
		return NewGoquError("Type must be a pointer to a slice when calling ScanVals")
	}
	t, _, isSliceOfPointers := getTypeInfo(i, val)
	rows, err := me.database.Query(me.Sql, me.Args...)
	if err != nil {
		return err
	}
	defer rows.Close()
	for rows.Next() {
		row := reflect.New(t)
		if err := rows.Scan(row.Interface()); err != nil {
			return err
		}
		if isSliceOfPointers {
			val.Set(reflect.Append(val, row))
		} else {
			val.Set(reflect.Append(val, reflect.Indirect(row)))
		}
	}
	if err := rows.Err(); err != nil {
		return err
	}
	return nil

}

func GetSliceConvert(c *Convertors) func(*Params, string, reflect.Type) reflect.Value {
	return func(p *Params, name string, typ reflect.Type) reflect.Value {
		var values ItemByIndex
		var maxIdx = 0
		var noindex = 0
		processItem := func(key string, vals []string) {
			var idx int
			var err error
			if !strings.HasPrefix(key, name+"[") {
				return
			}

			lIdx, rIdx := len(name), strings.IndexByte(key[len(name):], ']')+len(name)
			if rIdx == -1 {
				//not have ] char in key
				return
			}
			//process e.g. name[]
			if lIdx == rIdx-1 {
				noindex++
				goto END
			}

			idx, err = strconv.Atoi(key[lIdx+1 : rIdx])
			if err != nil {
				return
			}
			if idx > maxIdx {
				maxIdx = idx
			}
		END:
			value := c.Convert(p, key[:rIdx+1], typ.Elem())
			values = append(values, &item{idx, value})

		}
		for k, vals := range p.Values {
			processItem(k, vals)
		}
		//if array len small than 10000, keep index
		if maxIdx < 10000 {
			slice := reflect.MakeSlice(typ, maxIdx+1, maxIdx+noindex+1)
			for _, val := range values {
				if val.index > -1 {
					slice.Index(val.index).Set(val.value)
				} else {
					slice = reflect.Append(slice, val.value)
				}
			}
			return slice
		}

		sort.Sort(values)
		slice := reflect.MakeSlice(typ, 0, len(values))
		for _, val := range values {
			slice = reflect.Append(slice, val.value)
		}
		return slice
	}
}

// Fully scan a sql.Rows result into the dest slice.  StructScan destinations MUST
// have fields that map to every column in the result, and they MAY have fields
// in addition to those.  Fields are mapped to column names by lowercasing the
// field names by default:  use the struct tag `db` to specify exact column names
// for each field.
//
// StructScan will scan in the entire rows result, so if you need do not want to
// allocate structs for the entire result, use Queryx and see sqlx.Rows.StructScan.
func StructScan(rows *sql.Rows, dest interface{}) error {
	var v, vp reflect.Value
	var isPtr bool

	value := reflect.ValueOf(dest)
	if value.Kind() != reflect.Ptr {
		return errors.New("Must pass a pointer, not a value, to StructScan destination.")
	}

	direct := reflect.Indirect(value)

	slice, err := BaseSliceType(value.Type())
	if err != nil {
		return err
	}
	isPtr = slice.Elem().Kind() == reflect.Ptr
	base, err := BaseStructType(slice.Elem())
	if err != nil {
		return err
	}

	fm, err := getFieldmap(base)
	if err != nil {
		return err
	}

	columns, err := rows.Columns()
	if err != nil {
		return err
	}

	fields, err := getFields(fm, columns)
	if err != nil {
		return err
	}
	// this will hold interfaces which are pointers to each field in the struct
	values := make([]interface{}, len(columns))
	for rows.Next() {
		// create a new struct type (which returns PtrTo) and indirect it
		vp = reflect.New(base)
		v = reflect.Indirect(vp)

		setValues(fields, v, values)

		// scan into the struct field pointers and append to our results
		err = rows.Scan(values...)
		if err != nil {
			return err
		}
		if isPtr {
			direct.Set(reflect.Append(direct, vp))
		} else {
			direct.Set(reflect.Append(direct, v))
		}
	}

	return nil
}