Add support for multiple artists

README.org

@@ -43,7 +43,7 @@ The library is implemented around a set of entities.
 | *Name*           | *Type*    | *Fields*             | *Description*                                           |
 |------------------+-----------+----------------------+---------------------------------------------------------|
 | song             | structure | name, album, file, … |                                                         |
-| album            | structure | name, date, artist   |                                                         |
+| album            | structure | name, date, artists  |                                                         |
 | artist           | structure | name                 |                                                         |
 | genre            | structure | name                 |                                                         |
 | directory        | structure | name, path           |                                                         |

libmpdel.el

@@ -173,7 +173,7 @@ message from the server.")
                (:conc-name libmpdel--album-))
   (name nil :read-only t)
   (date nil :read-only t)
-  (artist nil :read-only t))
+  (artists nil :read-only t))
 
 (cl-defstruct (libmpdel-song
                (:constructor libmpdel--song-create)
@@ -184,6 +184,7 @@ message from the server.")
   (album nil :read-only t)
   (performers nil :read-only t)
   (genres nil :read-only t)
+  (artists nil :read-only t)
   (disc nil :read-only t)
   (date nil :read-only t)
   (id nil :read-only t)
@@ -214,20 +215,28 @@ message from the server.")
   "Return artist name of ENTITY."
   (libmpdel--artist-name (libmpdel-artist entity)))
 
+(defun libmpdel-artists-name (entity)
+  "Return semicolon separated string of artists names of ENTITY."
+  (string-join (mapcar #'libmpdel--artist-name
+                       (libmpdel-artists entity))
+               "; "))
+
 (cl-defgeneric libmpdel-artist (entity)
-  "Return artist of ENTITY.")
+  "Return artist of ENTITY."
+  (or (car (libmpdel-artists entity))
+      libmpdel--unknown-artist))
 
-(cl-defmethod libmpdel-artist ((artist libmpdel-artist))
-  "Return ARTIST."
-  artist)
+(cl-defmethod libmpdel-artists ((artist libmpdel-artist))
+  "Return singleton list containing ARTIST."
+  (list artist))
 
-(cl-defmethod libmpdel-artist ((album libmpdel-album))
+(cl-defmethod libmpdel-artists ((album libmpdel-album))
   "Return the ALBUM's artist."
-  (libmpdel--album-artist album))
+  (libmpdel--album-artists album))
 
-(cl-defmethod libmpdel-artist ((song libmpdel-song))
-  "Return the SONG's artist."
-  (libmpdel-artist (libmpdel--song-album song)))
+(cl-defmethod libmpdel-artists ((song libmpdel-song))
+  "Return the SONG's artists."
+  (libmpdel--song-artists song))
 
 (defun libmpdel-album-name (entity)
   "Return album name of ENTITY."
@@ -399,6 +408,7 @@ If the SONG's name is nil, return the filename instead."
    :file (cdr (assq 'file song-data))
    :performers (libmpdel--artists-create (libmpdel-entries song-data 'Performer))
    :genres (libmpdel--genres-create (libmpdel-entries song-data 'Genre))
+   :artists (libmpdel--artists-create (libmpdel-entries song-data 'Artist))
    :album (libmpdel--create-album-from-data song-data)
    :date (cdr (assq 'Date song-data))
    :disc (cdr (assq 'Disc song-data))
@@ -414,7 +424,7 @@ If the SONG's name is nil, return the filename instead."
   (libmpdel--album-create
    :name (cdr (assq 'Album song-data))
    :date (cdr (assq 'Date song-data))
-   :artist (libmpdel--artist-create :name (cdr (assq 'Artist song-data)))))
+   :artists (libmpdel--artists-create (libmpdel-entries song-data 'AlbumArtist))))
 
 (defun libmpdel--create-albums-from-data (data)
   "Return a list of albums from DATA, a server's response."
@@ -983,7 +993,11 @@ If HANDLER is nil, ignore response."
 (cl-defmethod libmpdel-entity-to-criteria ((album libmpdel-album))
   "Return search query matching all songs from ALBUM."
   (format "%s album %S"
-          (libmpdel-entity-to-criteria (libmpdel-artist album))
+          (string-join
+           (mapcar (lambda (artist)
+                     (format "albumartist %S" (libmpdel-entity-name artist)))
+                   (libmpdel-artists album))
+           " ")
           (libmpdel-entity-name album)))
 
 (cl-defmethod libmpdel-entity-to-criteria ((genre libmpdel-genre))
@@ -993,7 +1007,12 @@ If HANDLER is nil, ignore response."
 
 (cl-defmethod libmpdel-entity-to-criteria ((song libmpdel-song))
   "Return search query matching SONG."
-  (format "%s title %S"
+  (format "%s %s title %S"
+          (string-join
+           (mapcar (lambda (artist)
+                     (format "artist %S" (libmpdel-entity-name artist)))
+                   (libmpdel-artists song))
+           " ")
           (libmpdel-entity-to-criteria (libmpdel-album song))
           (libmpdel-entity-name song)))
 

test/libmpdel-test.el

@@ -54,39 +54,39 @@
 
 (ert-deftest libmpdel-test-artist ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist))
-         (song (libmpdel--song-create :name "The song" :album album)))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist)))
+         (song (libmpdel--song-create :name "The song" :album album :artists (list artist))))
     (should (equal artist (libmpdel-artist artist)))
     (should (equal artist (libmpdel-artist album)))
     (should (equal artist (libmpdel-artist song)))))
 
 (ert-deftest libmpdel-test-artist-name ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist))
-         (song (libmpdel--song-create :name "The song" :album album)))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist)))
+         (song (libmpdel--song-create :name "The song" :album album :artists (list artist))))
     (should (equal "The Artist" (libmpdel-artist-name artist)))
     (should (equal "The Artist" (libmpdel-artist-name album)))
     (should (equal "The Artist" (libmpdel-artist-name song)))))
 
 (ert-deftest libmpdel-test-album-name ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist)))
          (song (libmpdel--song-create :name "The song" :album album)))
     (should-error (libmpdel-album-name artist))
     (should (equal "The Album" (libmpdel-album-name album)))
     (should (equal "The Album" (libmpdel-album-name song)))))
 
 (ert-deftest libmpdel-test-album ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist)))
          (song (libmpdel--song-create :name "The song" :album album)))
     (should-error (libmpdel-album artist))
     (should (equal album (libmpdel-album album)))
     (should (equal album (libmpdel-album song)))))
 
 (ert-deftest libmpdel-test-entity-name ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist)))
          (song (libmpdel--song-create :name "The song" :album album))
          (stored-playlist (libmpdel--stored-playlist-create :name "The playlist")))
     (should (equal "The Artist" (libmpdel-entity-name artist)))
@@ -101,7 +101,7 @@
 
 (ert-deftest libmpdel-test-entity-parent ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist)))
          (song (libmpdel--song-create :name "The song" :album album))
          (stored-playlist (libmpdel--stored-playlist-create :name "The playlist")))
     (should (equal 'artists (libmpdel-entity-parent artist)))
@@ -122,6 +122,7 @@
                  (Performer . "The Pianist")
                  (Performer . "The Singer")
                  (Genre . "The Genre")
+                 (AlbumArtist . "The Albumartist")
                  (Artist . "The Artist")))))
     (should (equal "The song" (libmpdel-entity-name song)))
     (should (equal "foo/song.ogg" (libmpdel-song-file song)))
@@ -131,7 +132,8 @@
     (should (equal "The Album" (libmpdel-entity-name (libmpdel-album song))))
     (should (equal (list "The Violinist" "The Pianist" "The Singer")
                    (mapcar #'libmpdel-entity-name (libmpdel-performers song))))
-    (should (equal "The Artist" (libmpdel-entity-name (libmpdel-artist (libmpdel-album song)))))))
+    (should (equal "The Artist" (libmpdel-entity-name (libmpdel-artist song))))
+    (should (equal "The Albumartist" (libmpdel-entity-name (libmpdel-artist (libmpdel-album song)))))))
 
 (ert-deftest libmpdel-test-current-playlist-p ()
   (should (libmpdel-current-playlist-p 'current-playlist))
@@ -279,20 +281,22 @@
 
 (ert-deftest libmpdel-test-playlist-add-no-string-id-sends-findadd ()
   (let* ((artist (libmpdel--artist-create :name "The Artist"))
-         (album (libmpdel--album-create :name "The Album" :artist artist)))
+         (album (libmpdel--album-create :name "The Album" :artists (list artist))))
    (libmpdel-test--with-connection
     (libmpdel-playlist-add album 'current-playlist)
-    (should (equal '("findadd artist \"The Artist\" album \"The Album\"")
+    (should (equal '("findadd albumartist \"The Artist\" album \"The Album\"")
                    (last commands))))))
 
 (ert-deftest libmpdel-test-playlist-add-sends-findadd ()
  (let ((song (libmpdel--create-song-from-data
                '((Title . "S")
                  (Album . "A")
+                 (AlbumArtist . "Art")
+                 (AlbumArtist . "Bart")
                  (Artist . "Art")))))
    (libmpdel-test--with-connection
     (libmpdel-playlist-add song 'current-playlist)
-    (should (equal '("findadd artist \"Art\" album \"A\" title \"S\"")
+    (should (equal '("findadd artist \"Art\" albumartist \"Art\" albumartist \"Bart\" album \"A\" title \"S\"")
                    (last commands))))))
 
 
@@ -333,9 +337,9 @@
   (let* ((artist1 (libmpdel--artist-create :name "artist1"))
          (artist1-bis (libmpdel--artist-create :name "artist1"))
          (artist2 (libmpdel--artist-create :name "artist2"))
-         (album1 (libmpdel--album-create :name "album1" :artist artist1))
-         (album1-bis (libmpdel--album-create :name "album1" :artist artist1))
-         (album2 (libmpdel--album-create :name "album2" :artist artist1))
+         (album1 (libmpdel--album-create :name "album1" :artists (list artist1)))
+         (album1-bis (libmpdel--album-create :name "album1" :artists (list artist1)))
+         (album2 (libmpdel--album-create :name "album2" :artists (list artist1)))
          (song1 (libmpdel--song-create
                  :name "name"
                  :file "file"