treewide: copy to address

This saves the unnecessary extra copy.

Signed-off-by: Yonah <contrib@gensokyo.uk>

album.go

@@ -62,40 +62,43 @@ func (a *Album) IsFull() bool { return a.Belong != "" && len(a.Songs) > 0 }
 // Copy makes a copy of [Album].
 // For an [Album] where the IsFull method returns true, Copy zeroes fields to convert the copy into other variants.
 // For [Album] where IsFull returns false, any variant other than [AlbumVariantCurrent] is undefined.
-func (a *Album) Copy(variant int) *Album {
+func (a *Album) Copy(v *Album, variant int) bool {
-	if a == nil {
+	if v == nil || a == nil || v == a {
-		return nil
+		return false
 	}
 
-	v := *a
 	if variant == AlbumVariantCurrent {
-		return &v
+		*v = *a
+		return true
 	}
 	if !a.IsFull() {
-		return nil
+		return false
 	}
 
 	switch variant {
 	case AlbumVariantFull:
-		break
+		*v = *a
 
 	case AlbumVariantDetail:
-		a.Artists = nil
+		*v = *a
+		v.Artists = nil
 
 	case AlbumVariantData:
-		a.Songs = nil
+		*v = *a
+		v.Songs = nil
 
 	case AlbumVariantBase:
-		a.Intro = ""
+		*v = *a
-		a.Belong = ""
+		v.Intro = ""
-		a.CoverDeURL = ""
+		v.Belong = ""
-		a.Songs = nil
+		v.CoverDeURL = ""
+		v.Songs = nil
 
 	default:
-		return nil
+		return false
 	}
 
-	return a
+	return true
 }
 
 // Enrich populates the remaining fields of a non-full [Album].

album_test.go

@@ -33,24 +33,25 @@ func TestAlbum(t *testing.T) {
 			name    string
 			a       *Album
 			variant int
-			want    *Album
+			want    Album
+			wantOk  bool
 		}{
-			{"nil", nil, AlbumVariantDetail, nil},
+			{"nil", nil, AlbumVariantDetail, Album{CID: -0xdeadbeef}, false},
-			{"current", new(Album), AlbumVariantCurrent, new(Album)},
+			{"current", new(Album), AlbumVariantCurrent, Album{}, true},
-			{"full guard", new(Album), AlbumVariantDetail, nil},
+			{"full guard", new(Album), AlbumVariantDetail, Album{CID: -0xdeadbeef}, false},
 
 			{"current full", &Album{
 				Belong: "\x00",
 				Songs:  []AlbumSong{{}},
-			}, AlbumVariantCurrent, &Album{
+			}, AlbumVariantCurrent, Album{
 				Belong: "\x00",
 				Songs:  []AlbumSong{{}},
-			}},
+			}, true},
 
 			{"oob", &Album{
 				Belong: "\x00",
 				Songs:  []AlbumSong{{}},
-			}, 0xbad, nil},
+			}, 0xbad, Album{CID: -0xdeadbeef}, false},
 
 			{"full", &Album{
 				CID:        1030,
@@ -64,7 +65,7 @@ func TestAlbum(t *testing.T) {
 					{CID: 125012, Name: "Speed of Light (Instrumental)", Artists: []string{"DJ Okawari"}},
 				},
 				Artists: []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}, AlbumVariantFull, &Album{
+			}, AlbumVariantFull, Album{
 				CID:        1030,
 				Name:       "Speed of Light",
 				Intro:      "在无人告知方向的黑夜里，独自以光速探寻正确的道路。 \n无论看待世界是简单，亦或是复杂，大地和天空始终让开始与结束相连。 \n《Speed of Light》，通过乐调铺陈的驰放与内敛感，希望能为您呈现超脱于现实的惬意想象空间。 \n愿您掌心的小小地图一直指引着前路。像光一样前行，如企鹅物流般永不停歇。",
@@ -76,7 +77,7 @@ func TestAlbum(t *testing.T) {
 					{CID: 125012, Name: "Speed of Light (Instrumental)", Artists: []string{"DJ Okawari"}},
 				},
 				Artists: []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}},
+			}, true},
 
 			{"detail", &Album{
 				CID:        1030,
@@ -90,7 +91,7 @@ func TestAlbum(t *testing.T) {
 					{CID: 125012, Name: "Speed of Light (Instrumental)", Artists: []string{"DJ Okawari"}},
 				},
 				Artists: []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}, AlbumVariantDetail, &Album{
+			}, AlbumVariantDetail, Album{
 				CID:        1030,
 				Name:       "Speed of Light",
 				Intro:      "在无人告知方向的黑夜里，独自以光速探寻正确的道路。 \n无论看待世界是简单，亦或是复杂，大地和天空始终让开始与结束相连。 \n《Speed of Light》，通过乐调铺陈的驰放与内敛感，希望能为您呈现超脱于现实的惬意想象空间。 \n愿您掌心的小小地图一直指引着前路。像光一样前行，如企鹅物流般永不停歇。",
@@ -101,7 +102,7 @@ func TestAlbum(t *testing.T) {
 					{CID: 880374, Name: "Speed of Light", Artists: []string{"塞壬唱片-MSR", "DJ Okawari"}},
 					{CID: 125012, Name: "Speed of Light (Instrumental)", Artists: []string{"DJ Okawari"}},
 				},
-			}},
+			}, true},
 
 			{"data", &Album{
 				CID:        1030,
@@ -115,7 +116,7 @@ func TestAlbum(t *testing.T) {
 					{CID: 125012, Name: "Speed of Light (Instrumental)", Artists: []string{"DJ Okawari"}},
 				},
 				Artists: []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}, AlbumVariantData, &Album{
+			}, AlbumVariantData, Album{
 				CID:        1030,
 				Name:       "Speed of Light",
 				Intro:      "在无人告知方向的黑夜里，独自以光速探寻正确的道路。 \n无论看待世界是简单，亦或是复杂，大地和天空始终让开始与结束相连。 \n《Speed of Light》，通过乐调铺陈的驰放与内敛感，希望能为您呈现超脱于现实的惬意想象空间。 \n愿您掌心的小小地图一直指引着前路。像光一样前行，如企鹅物流般永不停歇。",
@@ -123,7 +124,7 @@ func TestAlbum(t *testing.T) {
 				CoverDeURL: "https://web.hycdn.cn/siren/pic/20210322/0bf0d84e08b57acd2455b412224ba8e8.jpg",
 				CoverURL:   "https://web.hycdn.cn/siren/pic/20210322/56cbcd1d0093d8ee8ee22bf6d68ab4a6.jpg",
 				Artists:    []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}},
+			}, true},
 
 			{"base", &Album{
 				CID:        1030,
@@ -137,16 +138,20 @@ func TestAlbum(t *testing.T) {
 					{CID: 125012, Name: "Speed of Light (Instrumental)", Artists: []string{"DJ Okawari"}},
 				},
 				Artists: []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}, AlbumVariantBase, &Album{
+			}, AlbumVariantBase, Album{
 				CID:      1030,
 				Name:     "Speed of Light",
 				CoverURL: "https://web.hycdn.cn/siren/pic/20210322/56cbcd1d0093d8ee8ee22bf6d68ab4a6.jpg",
 				Artists:  []string{"塞壬唱片-MSR", "DJ Okawari"},
-			}},
+			}, true},
 		}
 		for _, tc := range testCases {
 			t.Run(tc.name, func(t *testing.T) {
-				if got := tc.a.Copy(tc.variant); !reflect.DeepEqual(got, tc.want) {
+				got := Album{CID: -0xdeadbeef}
+				if ok := tc.a.Copy(&got, tc.variant); ok != tc.wantOk {
+					t.Errorf("Copy: ok = %v, want %v", ok, tc.wantOk)
+				}
+				if !reflect.DeepEqual(got, tc.want) {
 					t.Errorf("Copy: %#v, want %#v", got, tc.want)
 				}
 			})

song.go

@@ -41,34 +41,35 @@ func (s *Song) IsFull() bool { return s.SourceURL != "" }
 // Copy makes a copy of [Song].
 // For a [Song] where the IsFull method returns true, Copy zeroes fields to convert the copy into other variants.
 // For [Song] where IsFull returns false, any variant other than [SongVariantCurrent] is undefined.
-func (s *Song) Copy(variant int) *Song {
+func (s *Song) Copy(v *Song, variant int) bool {
-	if s == nil {
+	if v == nil || s == nil || v == s {
-		return nil
+		return false
 	}
 
-	v := *s
 	if variant == SongVariantCurrent {
-		return &v
+		*v = *s
+		return true
 	}
 	if !s.IsFull() {
-		return nil
+		return false
 	}
 
 	switch variant {
 	case SongVariantFull:
-		break
+		*v = *s
 
 	case SongVariantBase:
-		s.SourceURL = ""
+		*v = *s
-		s.LyricURL = ""
+		v.SourceURL = ""
-		s.MvURL = ""
+		v.LyricURL = ""
-		s.MvCoverURL = ""
+		v.MvURL = ""
+		v.MvCoverURL = ""
 
 	default:
-		return nil
+		return false
 	}
 
-	return s
+	return true
 }
 
 // Enrich populates the remaining fields of a non-full [Song].

song_test.go

@@ -28,21 +28,22 @@ func TestSong(t *testing.T) {
 			name    string
 			a       *Song
 			variant int
-			want    *Song
+			want    Song
+			wantOk  bool
 		}{
-			{"nil", nil, SongVariantBase, nil},
+			{"nil", nil, SongVariantBase, Song{CID: -0xdeadbeef}, false},
-			{"current", new(Song), SongVariantCurrent, new(Song)},
+			{"current", new(Song), SongVariantCurrent, Song{}, true},
-			{"full guard", new(Song), SongVariantFull, nil},
+			{"full guard", new(Song), SongVariantFull, Song{CID: -0xdeadbeef}, false},
 
 			{"current full", &Song{
 				SourceURL: "\x00",
-			}, SongVariantCurrent, &Song{
+			}, SongVariantCurrent, Song{
 				SourceURL: "\x00",
-			}},
+			}, true},
 
 			{"oob", &Song{
 				SourceURL: "\x00",
-			}, 0xbad, nil},
+			}, 0xbad, Song{CID: -0xdeadbeef}, false},
 
 			{"full", &Song{
 				CID:       48794,
@@ -51,14 +52,14 @@ func TestSong(t *testing.T) {
 				SourceURL: "https://res01.hycdn.cn/04ce5de54bb52eb85008644d541d40fa/68CA0442/siren/audio/20240709/a7f650238eaefc9c30a9627d7f78d819.wav",
 				LyricURL:  "https://web.hycdn.cn/siren/lyric/20240709/4a10c70629b68a187fdbef4a27bd32d8.lrc",
 				Artists:   []string{"塞壬唱片-MSR"},
-			}, SongVariantFull, &Song{
+			}, SongVariantFull, Song{
 				CID:       48794,
 				Name:      "Warm and Small Light",
 				AlbumCID:  6660,
 				SourceURL: "https://res01.hycdn.cn/04ce5de54bb52eb85008644d541d40fa/68CA0442/siren/audio/20240709/a7f650238eaefc9c30a9627d7f78d819.wav",
 				LyricURL:  "https://web.hycdn.cn/siren/lyric/20240709/4a10c70629b68a187fdbef4a27bd32d8.lrc",
 				Artists:   []string{"塞壬唱片-MSR"},
-			}},
+			}, true},
 
 			{"base", &Song{
 				CID:       48794,
@@ -67,16 +68,20 @@ func TestSong(t *testing.T) {
 				SourceURL: "https://res01.hycdn.cn/04ce5de54bb52eb85008644d541d40fa/68CA0442/siren/audio/20240709/a7f650238eaefc9c30a9627d7f78d819.wav",
 				LyricURL:  "https://web.hycdn.cn/siren/lyric/20240709/4a10c70629b68a187fdbef4a27bd32d8.lrc",
 				Artists:   []string{"塞壬唱片-MSR"},
-			}, SongVariantBase, &Song{
+			}, SongVariantBase, Song{
 				CID:      48794,
 				Name:     "Warm and Small Light",
 				AlbumCID: 6660,
 				Artists:  []string{"塞壬唱片-MSR"},
-			}},
+			}, true},
 		}
 		for _, tc := range testCases {
 			t.Run(tc.name, func(t *testing.T) {
-				if got := tc.a.Copy(tc.variant); !reflect.DeepEqual(got, tc.want) {
+				got := Song{CID: -0xdeadbeef}
+				if ok := tc.a.Copy(&got, tc.variant); ok != tc.wantOk {
+					t.Errorf("Copy: ok = %v, want %v", ok, tc.wantOk)
+				}
+				if !reflect.DeepEqual(got, tc.want) {
 					t.Errorf("Copy: %#v, want %#v", got, tc.want)
 				}
 			})