116 lines
2.7 KiB
Go
116 lines
2.7 KiB
Go
package null
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import (
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"database/sql"
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"encoding/json"
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"fmt"
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"reflect"
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"strconv"
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)
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// Int is an nullable int64.
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// It does not consider zero values to be null.
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// It will decode to null, not zero, if null.
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type Int struct {
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sql.NullInt64
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}
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// NewInt creates a new Int
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func NewInt(i int64, valid bool) Int {
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return Int{
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NullInt64: sql.NullInt64{
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Int64: i,
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Valid: valid,
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},
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}
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}
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// IntFrom creates a new Int that will always be valid.
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func IntFrom(i int64) Int {
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return NewInt(i, true)
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}
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// IntFromPtr creates a new Int that be null if i is nil.
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func IntFromPtr(i *int64) Int {
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if i == nil {
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return NewInt(0, false)
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}
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return NewInt(*i, true)
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}
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// UnmarshalJSON implements json.Unmarshaler.
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// It supports number and null input.
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// 0 will not be considered a null Int.
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// It also supports unmarshalling a sql.NullInt64.
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func (i *Int) UnmarshalJSON(data []byte) error {
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var err error
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var v interface{}
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json.Unmarshal(data, &v)
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switch v.(type) {
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case float64:
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// Unmarshal again, directly to int64, to avoid intermediate float64
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err = json.Unmarshal(data, &i.Int64)
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case map[string]interface{}:
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err = json.Unmarshal(data, &i.NullInt64)
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case nil:
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i.Valid = false
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return nil
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default:
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err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Int", reflect.TypeOf(v).Name())
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}
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i.Valid = err == nil
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return err
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}
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// UnmarshalText implements encoding.TextUnmarshaler.
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// It will unmarshal to a null Int if the input is a blank or not an integer.
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// It will return an error if the input is not an integer, blank, or "null".
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func (i *Int) UnmarshalText(text []byte) error {
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str := string(text)
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if str == "" || str == "null" {
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i.Valid = false
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return nil
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}
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var err error
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i.Int64, err = strconv.ParseInt(string(text), 10, 64)
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i.Valid = err == nil
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return err
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}
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// MarshalJSON implements json.Marshaler.
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// It will encode null if this Int is null.
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func (i Int) MarshalJSON() ([]byte, error) {
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if !i.Valid {
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return []byte("null"), nil
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}
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return []byte(strconv.FormatInt(i.Int64, 10)), nil
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}
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// MarshalText implements encoding.TextMarshaler.
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// It will encode a blank string if this Int is null.
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func (i Int) MarshalText() ([]byte, error) {
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if !i.Valid {
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return []byte{}, nil
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}
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return []byte(strconv.FormatInt(i.Int64, 10)), nil
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}
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// SetValid changes this Int's value and also sets it to be non-null.
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func (i *Int) SetValid(n int64) {
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i.Int64 = n
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i.Valid = true
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}
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// Ptr returns a pointer to this Int's value, or a nil pointer if this Int is null.
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func (i Int) Ptr() *int64 {
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if !i.Valid {
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return nil
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}
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return &i.Int64
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}
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// IsZero returns true for invalid Ints, for future omitempty support (Go 1.4?)
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// A non-null Int with a 0 value will not be considered zero.
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func (i Int) IsZero() bool {
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return !i.Valid
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}
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