From 58b185606ce70e76dd19d5700c68c8fb99cf1ee7 Mon Sep 17 00:00:00 2001
From: it512 <it512@msn.com>
Date: Sun, 29 Sep 2024 22:11:05 +0800
Subject: [PATCH] feat add IsZero

---
 null.go      | 22 +++++++++++++---------
 null_test.go | 17 +++++++++++++++++
 uuid.go      | 17 ++++++++++++-----
 uuid_test.go | 12 ++++++++++++
 4 files changed, 54 insertions(+), 14 deletions(-)

diff --git a/null.go b/null.go
index d7fcbf2..293779c 100644
--- a/null.go
+++ b/null.go
@@ -17,15 +17,14 @@ var jsonNull = []byte("null")
 // NullUUID implements the SQL driver.Scanner interface so
 // it can be used as a scan destination:
 //
-//  var u uuid.NullUUID
-//  err := db.QueryRow("SELECT name FROM foo WHERE id=?", id).Scan(&u)
-//  ...
-//  if u.Valid {
-//     // use u.UUID
-//  } else {
-//     // NULL value
-//  }
-//
+//	var u uuid.NullUUID
+//	err := db.QueryRow("SELECT name FROM foo WHERE id=?", id).Scan(&u)
+//	...
+//	if u.Valid {
+//	   // use u.UUID
+//	} else {
+//	   // NULL value
+//	}
 type NullUUID struct {
 	UUID  UUID
 	Valid bool // Valid is true if UUID is not NULL
@@ -116,3 +115,8 @@ func (nu *NullUUID) UnmarshalJSON(data []byte) error {
 	nu.Valid = err == nil
 	return err
 }
+
+// IsZero determine whether the value is zero
+func (nu NullUUID) IsZero() bool {
+	return nu.Valid && nu.UUID == Nil
+}
diff --git a/null_test.go b/null_test.go
index fe0fe8d..a8a5fa1 100644
--- a/null_test.go
+++ b/null_test.go
@@ -212,3 +212,20 @@ func TestNullUUIDUnmarshalJSON(t *testing.T) {
 		t.Errorf("expected nil when unmarshalling null, got %s", err)
 	}
 }
+
+func TestNullUUIDIsZero(t *testing.T) {
+	var nu NullUUID
+	if nu.IsZero() {
+		t.Error("expected false got true")
+	}
+
+	nu.Valid = true
+	if !nu.IsZero() {
+		t.Error("expected true got false")
+	}
+
+	nu.UUID = Max
+	if nu.IsZero() {
+		t.Error("expected false got true")
+	}
+}
diff --git a/uuid.go b/uuid.go
index dc75cee..ef7e356 100644
--- a/uuid.go
+++ b/uuid.go
@@ -52,7 +52,7 @@ var (
 	ErrInvalidBracketedFormat = errors.New("invalid bracketed UUID format")
 )
 
-type URNPrefixError struct { prefix string }
+type URNPrefixError struct{ prefix string }
 
 func (e URNPrefixError) Error() string {
 	return fmt.Sprintf("invalid urn prefix: %q", e.prefix)
@@ -215,10 +215,12 @@ func Must(uuid UUID, err error) UUID {
 }
 
 // Validate returns an error if s is not a properly formatted UUID in one of the following formats:
-//   xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
-//   urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
-//   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
-//   {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
+//
+//	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+//	urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+//	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+//	{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
+//
 // It returns an error if the format is invalid, otherwise nil.
 func Validate(s string) error {
 	switch len(s) {
@@ -315,6 +317,11 @@ func (uuid UUID) Version() Version {
 	return Version(uuid[6] >> 4)
 }
 
+// IsZero determine whether the value is zero
+func (uuid UUID) IsZero() bool {
+	return uuid == Nil
+}
+
 func (v Version) String() string {
 	if v > 15 {
 		return fmt.Sprintf("BAD_VERSION_%d", v)
diff --git a/uuid_test.go b/uuid_test.go
index 906ecbe..f091a09 100644
--- a/uuid_test.go
+++ b/uuid_test.go
@@ -928,3 +928,15 @@ func TestVersion7MonotonicityStrict(t *testing.T) {
 		u1 = u2
 	}
 }
+
+func TestUUIDIsZero(t *testing.T) {
+	var u UUID
+	if !u.IsZero() {
+		t.Error("expected true got false")
+	}
+
+	u = New()
+	if u.IsZero() {
+		t.Error("expected false got true")
+	}
+}