Add 'null/' from commit '109a79fb20'

Repo: github.com/lbryio/null.go

git-subtree-dir: null
git-subtree-mainline: 75e2abdeac
git-subtree-split: 109a79fb20

null/json.go

@@ -0,0 +1,157 @@
+package null
+
+import (
+	"bytes"
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	"gopkg.in/nullbio/null.v6/convert"
+)
+
+// JSON is a nullable []byte.
+type JSON struct {
+	JSON  []byte
+	Valid bool
+}
+
+// NewJSON creates a new JSON
+func NewJSON(b []byte, valid bool) JSON {
+	return JSON{
+		JSON:  b,
+		Valid: valid,
+	}
+}
+
+// JSONFrom creates a new JSON that will be invalid if nil.
+func JSONFrom(b []byte) JSON {
+	return NewJSON(b, b != nil)
+}
+
+// JSONFromPtr creates a new JSON that will be invalid if nil.
+func JSONFromPtr(b *[]byte) JSON {
+	if b == nil {
+		return NewJSON(nil, false)
+	}
+	n := NewJSON(*b, true)
+	return n
+}
+
+// Unmarshal will unmarshal your JSON stored in
+// your JSON object and store the result in the
+// value pointed to by dest.
+func (j JSON) Unmarshal(dest interface{}) error {
+	if dest == nil {
+		return errors.New("destination is nil, not a valid pointer to an object")
+	}
+
+	// Call our implementation of
+	// JSON MarshalJSON through json.Marshal
+	// to get the value of the JSON object
+	res, err := json.Marshal(j)
+	if err != nil {
+		return err
+	}
+
+	return json.Unmarshal(res, dest)
+}
+
+// UnmarshalJSON implements json.Unmarshaler.
+func (j *JSON) UnmarshalJSON(data []byte) error {
+	if data == nil {
+		return fmt.Errorf("json: cannot unmarshal nil into Go value of type null.JSON")
+	}
+
+	if bytes.Equal(data, NullBytes) {
+		j.JSON = NullBytes
+		j.Valid = false
+		return nil
+	}
+
+	j.Valid = true
+	j.JSON = make([]byte, len(data))
+	copy(j.JSON, data)
+
+	return nil
+}
+
+// UnmarshalText implements encoding.TextUnmarshaler.
+func (j *JSON) UnmarshalText(text []byte) error {
+	if text == nil || len(text) == 0 {
+		j.JSON = nil
+		j.Valid = false
+	} else {
+		j.JSON = append(j.JSON[0:0], text...)
+		j.Valid = true
+	}
+
+	return nil
+}
+
+// Marshal will marshal the passed in object,
+// and store it in the JSON member on the JSON object.
+func (j *JSON) Marshal(obj interface{}) error {
+	res, err := json.Marshal(obj)
+	if err != nil {
+		return err
+	}
+
+	// Call our implementation of
+	// JSON UnmarshalJSON through json.Unmarshal
+	// to set the result to the JSON object
+	return json.Unmarshal(res, j)
+}
+
+// MarshalJSON implements json.Marshaler.
+func (j JSON) MarshalJSON() ([]byte, error) {
+	if len(j.JSON) == 0 || j.JSON == nil {
+		return NullBytes, nil
+	}
+	return j.JSON, nil
+}
+
+// MarshalText implements encoding.TextMarshaler.
+func (j JSON) MarshalText() ([]byte, error) {
+	if !j.Valid {
+		return nil, nil
+	}
+	return j.JSON, nil
+}
+
+// SetValid changes this JSON's value and also sets it to be non-null.
+func (j *JSON) SetValid(n []byte) {
+	j.JSON = n
+	j.Valid = true
+}
+
+// Ptr returns a pointer to this JSON's value, or a nil pointer if this JSON is null.
+func (j JSON) Ptr() *[]byte {
+	if !j.Valid {
+		return nil
+	}
+	return &j.JSON
+}
+
+// IsNull returns true for null or zero JSON's, for future omitempty support (Go 1.4?)
+func (j JSON) IsNull() bool {
+	return !j.Valid
+}
+
+// Scan implements the Scanner interface.
+func (j *JSON) Scan(value interface{}) error {
+	if value == nil {
+		j.JSON, j.Valid = []byte{}, false
+		return nil
+	}
+	j.Valid = true
+	return convert.ConvertAssign(&j.JSON, value)
+}
+
+// Value implements the driver Valuer interface.
+func (j JSON) Value() (driver.Value, error) {
+	if !j.Valid {
+		return nil, nil
+	}
+	return j.JSON, nil
+}