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package pgtype
import "fmt"
// EnumType represents a enum type. While it implements Value, this is only in service of its type conversion duties
// when registered as a data type in a ConnType. It should not be used directly as a Value.
type EnumType struct {
value string
status Status
typeName string // PostgreSQL type name
members []string // enum members
membersMap map[string]string // map to quickly lookup member and reuse string instead of allocating
}
// NewEnumType initializes a new EnumType. It retains a read-only reference to members. members must not be changed.
func NewEnumType(typeName string, members []string) *EnumType {
et := &EnumType{typeName: typeName, members: members}
et.membersMap = make(map[string]string, len(members))
for _, m := range members {
et.membersMap[m] = m
}
return et
}
func (et *EnumType) NewTypeValue() Value {
return &EnumType{
value: et.value,
status: et.status,
typeName: et.typeName,
members: et.members,
membersMap: et.membersMap,
}
}
func (et *EnumType) TypeName() string {
return et.typeName
}
func (et *EnumType) Members() []string {
return et.members
}
// Set assigns src to dst. Set purposely does not check that src is a member. This allows continued error free
// operation in the event the PostgreSQL enum type is modified during a connection.
func (dst *EnumType) Set(src interface{}) error {
if src == nil {
dst.status = Null
return nil
}
if value, ok := src.(interface{ Get() interface{} }); ok {
value2 := value.Get()
if value2 != value {
return dst.Set(value2)
}
}
switch value := src.(type) {
case string:
dst.value = value
dst.status = Present
case *string:
if value == nil {
dst.status = Null
} else {
dst.value = *value
dst.status = Present
}
case []byte:
if value == nil {
dst.status = Null
} else {
dst.value = string(value)
dst.status = Present
}
default:
if originalSrc, ok := underlyingStringType(src); ok {
return dst.Set(originalSrc)
}
return fmt.Errorf("cannot convert %v to enum %s", value, dst.typeName)
}
return nil
}
func (dst EnumType) Get() interface{} {
switch dst.status {
case Present:
return dst.value
case Null:
return nil
default:
return dst.status
}
}
func (src *EnumType) AssignTo(dst interface{}) error {
switch src.status {
case Present:
switch v := dst.(type) {
case *string:
*v = src.value
return nil
case *[]byte:
*v = make([]byte, len(src.value))
copy(*v, src.value)
return nil
default:
if nextDst, retry := GetAssignToDstType(dst); retry {
return src.AssignTo(nextDst)
}
return fmt.Errorf("unable to assign to %T", dst)
}
case Null:
return NullAssignTo(dst)
}
return fmt.Errorf("cannot decode %#v into %T", src, dst)
}
func (EnumType) PreferredResultFormat() int16 {
return TextFormatCode
}
func (dst *EnumType) DecodeText(ci *ConnInfo, src []byte) error {
if src == nil {
dst.status = Null
return nil
}
// Lookup the string in membersMap to avoid an allocation.
if s, found := dst.membersMap[string(src)]; found {
dst.value = s
} else {
// If an enum type is modified after the initial connection it is possible to receive an unexpected value.
// Gracefully handle this situation. Purposely NOT modifying members and membersMap to allow for sharing members
// and membersMap between connections.
dst.value = string(src)
}
dst.status = Present
return nil
}
func (dst *EnumType) DecodeBinary(ci *ConnInfo, src []byte) error {
return dst.DecodeText(ci, src)
}
func (EnumType) PreferredParamFormat() int16 {
return TextFormatCode
}
func (src EnumType) EncodeText(ci *ConnInfo, buf []byte) ([]byte, error) {
switch src.status {
case Null:
return nil, nil
case Undefined:
return nil, errUndefined
}
return append(buf, src.value...), nil
}
func (src EnumType) EncodeBinary(ci *ConnInfo, buf []byte) ([]byte, error) {
return src.EncodeText(ci, buf)
}
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