094289d4cf
Repo: github.com/lbryio/null.go git-subtree-dir: null git-subtree-mainline:75e2abdeacgit-subtree-split:109a79fb20
118 lines
2.3 KiB
Go
118 lines
2.3 KiB
Go
package null
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import (
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"bytes"
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"database/sql/driver"
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"encoding/json"
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"gopkg.in/nullbio/null.v6/convert"
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)
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// String is a nullable string. It supports SQL and JSON serialization.
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type String struct {
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String string
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Valid bool
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}
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// StringFrom creates a new String that will never be blank.
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func StringFrom(s string) String {
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return NewString(s, true)
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}
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// StringFromPtr creates a new String that be null if s is nil.
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func StringFromPtr(s *string) String {
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if s == nil {
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return NewString("", false)
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}
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return NewString(*s, true)
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}
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// NewString creates a new String
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func NewString(s string, valid bool) String {
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return String{
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String: s,
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Valid: valid,
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}
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}
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// UnmarshalJSON implements json.Unmarshaler.
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func (s *String) UnmarshalJSON(data []byte) error {
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if bytes.Equal(data, NullBytes) {
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s.String = ""
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s.Valid = false
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return nil
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}
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if err := json.Unmarshal(data, &s.String); err != nil {
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return err
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}
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s.Valid = true
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return nil
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}
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// MarshalJSON implements json.Marshaler.
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func (s String) MarshalJSON() ([]byte, error) {
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if !s.Valid {
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return NullBytes, nil
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}
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return json.Marshal(s.String)
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}
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// MarshalText implements encoding.TextMarshaler.
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func (s String) MarshalText() ([]byte, error) {
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if !s.Valid {
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return []byte{}, nil
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}
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return []byte(s.String), nil
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}
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// UnmarshalText implements encoding.TextUnmarshaler.
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func (s *String) UnmarshalText(text []byte) error {
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if text == nil || len(text) == 0 {
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s.Valid = false
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return nil
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}
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s.String = string(text)
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s.Valid = true
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return nil
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}
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// SetValid changes this String's value and also sets it to be non-null.
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func (s *String) SetValid(v string) {
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s.String = v
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s.Valid = true
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}
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// Ptr returns a pointer to this String's value, or a nil pointer if this String is null.
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func (s String) Ptr() *string {
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if !s.Valid {
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return nil
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}
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return &s.String
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}
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// IsNull returns true for null strings, for potential future omitempty support.
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func (s String) IsNull() bool {
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return !s.Valid
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}
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// Scan implements the Scanner interface.
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func (s *String) Scan(value interface{}) error {
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if value == nil {
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s.String, s.Valid = "", false
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return nil
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}
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s.Valid = true
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return convert.ConvertAssign(&s.String, value)
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}
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// Value implements the driver Valuer interface.
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func (s String) Value() (driver.Value, error) {
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if !s.Valid {
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return nil, nil
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}
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return s.String, nil
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}
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