Support JSON serialization and deserialization of atomic.Time

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Add `String` method to `atomic.Pointer[T]` type allowing users to safely print
 underlying values of pointers.
+- Support JSON serialization and deserialization of `atomic.Time`
 
 ## [1.10.0] - 2022-08-11
 ### Added

time.go

@@ -23,6 +23,7 @@
 package atomic
 
 import (
+	"encoding/json"
 	"time"
 )
 
@@ -53,3 +54,18 @@ func (x *Time) Load() time.Time {
 func (x *Time) Store(val time.Time) {
 	x.v.Store(packTime(val))
 }
+
+// MarshalJSON encodes the wrapped time.Time into JSON.
+func (x *Time) MarshalJSON() ([]byte, error) {
+	return json.Marshal(x.Load())
+}
+
+// UnmarshalJSON decodes a time.Time from JSON.
+func (x *Time) UnmarshalJSON(b []byte) error {
+	var v time.Time
+	if err := json.Unmarshal(b, &v); err != nil {
+		return err
+	}
+	x.Store(v)
+	return nil
+}

time_ext.go

@@ -22,7 +22,7 @@ package atomic
 
 import "time"
 
-//go:generate bin/gen-atomicwrapper -name=Time -type=time.Time -wrapped=Value -pack=packTime -unpack=unpackTime -imports time -file=time.go
+//go:generate bin/gen-atomicwrapper -name=Time -type=time.Time -wrapped=Value -pack=packTime -unpack=unpackTime -json -imports time -file=time.go
 
 func packTime(t time.Time) interface{} {
 	return t

time_test.go

@@ -21,6 +21,7 @@
 package atomic
 
 import (
+	"encoding/json"
 	"testing"
 	"time"
 
@@ -71,6 +72,31 @@ func TestLargeTime(t *testing.T) {
 		atom.Store(dayBeforePast)
 		assert.Equal(t, 1677, atom.Load().Year())
 	})
+
+	t.Run("JSON/Marshal", func(t *testing.T) {
+		now := time.Now()
+		atom := NewTime(now)
+		bytes, err := json.Marshal(atom)
+		require.NoError(t, err, "json.Marshal errored unexpectedly.")
+
+		oBytes, err := json.Marshal(now)
+		require.NoError(t, err, "json.Marshal errored unexpectedly on the native time.Time.")
+		require.Equal(t, oBytes, bytes, "json.Marshal encoded the wrong bytes.")
+	})
+
+	t.Run("JSON/Unmarshal", func(t *testing.T) {
+		now := time.Now()
+		atom := NewTime(time.Time{})
+
+		oBytes, err := json.Marshal(now)
+		require.NoError(t, err, "json.Marshal errored unexpectedly on the native time.Time.")
+		err = json.Unmarshal(oBytes, &atom)
+		require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
+		// NOTE: https://pkg.go.dev/time#Time.MarshalJSON, the time is formatted as RFC 3339
+		// example: 2022-11-25T21:06:44.6023404+01:00
+		// So we cannot compare now and atom.Load() because we lack nanoseconds
+		require.Equal(t, now.UnixMicro(), atom.Load().UnixMicro(), "json.Unmarshal didn't set the correct value.")
+	})
 }
 
 func TestMonotonic(t *testing.T) {