implement nullable values for hstore maps

hstore.go

@@ -40,6 +40,16 @@ func (dst *Hstore) Set(src interface{}) error {
 			m[k] = Text{String: v, Status: Present}
 		}
 		*dst = Hstore{Map: m, Status: Present}
+	case map[string]*string:
+		m := make(map[string]Text, len(value))
+		for k, v := range value {
+			if v == nil {
+				m[k] = Text{Status: Null}
+			} else {
+				m[k] = Text{String: *v, Status: Present}
+			}
+		}
+		*dst = Hstore{Map: m, Status: Present}
 	default:
 		return fmt.Errorf("cannot convert %v to Hstore", src)
 	}
@@ -71,6 +81,19 @@ func (src *Hstore) AssignTo(dst interface{}) error {
 				(*v)[k] = val.String
 			}
 			return nil
+		case *map[string]*string:
+			*v = make(map[string]*string, len(src.Map))
+			for k, val := range src.Map {
+				switch val.Status {
+				case Null:
+					(*v)[k] = nil
+				case Present:
+					(*v)[k] = &val.String
+				default:
+					return fmt.Errorf("cannot decode %#v into %T", src, dst)
+				}
+			}
+			return nil
 		default:
 			if nextDst, retry := GetAssignToDstType(dst); retry {
 				return src.AssignTo(nextDst)

hstore_test.go

@@ -69,6 +69,50 @@ func TestHstoreTranscode(t *testing.T) {
 	})
 }
 
+func TestHstoreTranscodeNullable(t *testing.T) {
+	text := func(s string, status pgtype.Status) pgtype.Text {
+		return pgtype.Text{String: s, Status: status}
+	}
+
+	values := []interface{}{
+		&pgtype.Hstore{Map: map[string]pgtype.Text{"foo": text("", pgtype.Null)}, Status: pgtype.Present},
+	}
+
+	specialStrings := []string{
+		`"`,
+		`'`,
+		`\`,
+		`\\`,
+		`=>`,
+		` `,
+		`\ / / \\ => " ' " '`,
+	}
+	for _, s := range specialStrings {
+		// Special key values
+		values = append(values, &pgtype.Hstore{Map: map[string]pgtype.Text{s + "foo": text("", pgtype.Null)}, Status: pgtype.Present})         // at beginning
+		values = append(values, &pgtype.Hstore{Map: map[string]pgtype.Text{"foo" + s + "bar": text("", pgtype.Null)}, Status: pgtype.Present}) // in middle
+		values = append(values, &pgtype.Hstore{Map: map[string]pgtype.Text{"foo" + s: text("", pgtype.Null)}, Status: pgtype.Present})         // at end
+		values = append(values, &pgtype.Hstore{Map: map[string]pgtype.Text{s: text("", pgtype.Null)}, Status: pgtype.Present})                 // is key
+	}
+
+	testutil.TestSuccessfulTranscodeEqFunc(t, "hstore", values, func(ai, bi interface{}) bool {
+		a := ai.(pgtype.Hstore)
+		b := bi.(pgtype.Hstore)
+
+		if len(a.Map) != len(b.Map) || a.Status != b.Status {
+			return false
+		}
+
+		for k := range a.Map {
+			if a.Map[k] != b.Map[k] {
+				return false
+			}
+		}
+
+		return true
+	})
+}
+
 func TestHstoreSet(t *testing.T) {
 	successfulTests := []struct {
 		src    map[string]string
@@ -90,6 +134,27 @@ func TestHstoreSet(t *testing.T) {
 	}
 }
 
+func TestHstoreSetNullable(t *testing.T) {
+	successfulTests := []struct {
+		src    map[string]*string
+		result pgtype.Hstore
+	}{
+		{src: map[string]*string{"foo": nil}, result: pgtype.Hstore{Map: map[string]pgtype.Text{"foo": {Status: pgtype.Null}}, Status: pgtype.Present}},
+	}
+
+	for i, tt := range successfulTests {
+		var dst pgtype.Hstore
+		err := dst.Set(tt.src)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if !reflect.DeepEqual(dst, tt.result) {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.src, tt.result, dst)
+		}
+	}
+}
+
 func TestHstoreAssignTo(t *testing.T) {
 	var m map[string]string
 
@@ -113,3 +178,27 @@ func TestHstoreAssignTo(t *testing.T) {
 		}
 	}
 }
+
+func TestHstoreAssignToNullable(t *testing.T) {
+	var m map[string]*string
+
+	simpleTests := []struct {
+		src      pgtype.Hstore
+		dst      *map[string]*string
+		expected map[string]*string
+	}{
+		{src: pgtype.Hstore{Map: map[string]pgtype.Text{"foo": {Status: pgtype.Null}}, Status: pgtype.Present}, dst: &m, expected: map[string]*string{"foo": nil}},
+		{src: pgtype.Hstore{Status: pgtype.Null}, dst: &m, expected: ((map[string]*string)(nil))},
+	}
+
+	for i, tt := range simpleTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if !reflect.DeepEqual(*tt.dst, tt.expected) {
+			t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, *tt.dst)
+		}
+	}
+}