Made mpcl:connect more standardized.
[lisp-utils.git] / mpcl.lisp
CommitLineData
9d561d5d
FT
1;;;; MPCL -- Common Lisp MPD Client library
2
3#-sbcl (error "No known socket interface for ~a" (lisp-implementation-type))
4
5(eval-when (:compile-toplevel :load-toplevel :execute)
6 (require 'sb-bsd-sockets)
7 (require 'cl-ppcre))
8(defpackage :mpcl (:use :cl :sb-bsd-sockets))
9(in-package :mpcl)
10
11;;; Global variables
12(defvar *socket* nil)
13(defvar *last-command* 0)
14(defvar *last-server* nil)
15(defvar *retries* 0)
16#+sbcl (defvar *conn-lock* (sb-thread:make-mutex))
17
18;;; Utility functions
19(defmacro concat (&rest strings)
20 `(concatenate 'string ,@strings))
21
22(defun assert-type (type val)
23 (assert (typep val type))
24 val)
25
26(defun clipnum (num min max)
27 (cond ((< num min) min)
28 ((> num max) max)
29 (t num)))
30
31(defmacro regex-cond (key &body clauses)
32 (let ((match (gensym))
33 (sub (gensym))
34 (val (gensym))
35 (block-nm (gensym)))
36 (flet ((ctrans (clause)
37 (if (eq (first clause) 'otherwise)
38 `(return-from ,block-nm
39 (progn ,@(rest clause)))
40 (destructuring-bind (regex arglist &body body)
41 clause
42 `(multiple-value-bind (,match ,sub)
43 (ppcre:scan-to-strings ,regex ,val)
44 ,@(if (null arglist)
45 `((declare (ignore ,sub))))
46 (if ,match
47 (return-from ,block-nm
48 (let ,(let ((argno 0))
49 (mapcar #'(lambda (arg)
50 (prog1 `(,arg (aref ,sub ,argno))
51 (incf argno)))
52 arglist))
53 ,@body))))))))
54 `(block ,block-nm
55 (let ((,val (the string ,key)))
56 ,@(mapcar #'ctrans clauses))))))
57
58;;; Error conditions
59(define-condition protocol-error (error)
60 ((message :reader protocol-error-message
61 :initarg :message
62 :type string)
63 (real-error :reader protocol-error-cause
64 :initarg :cause
65 :type condition
66 :initform nil)
67 (retries :reader protocol-error-retries
68 :initarg :retries
69 :type integer
70 :initform 0))
71 (:report (lambda (c s)
72 (if (protocol-error-cause c)
73 (format s "~A: ~A" (protocol-error-message c) (protocol-error-cause c))
74 (format s "Protocol error occurred on mpd socket: ~A" (protocol-error-message c))))))
75
76(define-condition protocol-input-error (protocol-error)
77 ((inputs :reader protocol-error-inputs
78 :initarg :inputs))
79 (:report (lambda (c s)
80 (apply #'format s (protocol-error-message c) (protocol-error-inputs c)))))
81
82(define-condition command-error (error)
83 ((err-code :reader command-error-code
84 :initarg :err-code
85 :type integer)
86 (message :reader command-error-message
87 :initarg :message
88 :type string))
89 (:report (lambda (c s)
90 (format s "mpd error response: ~A" (command-error-message c)))))
91
92(defvar *command-error-types* (make-hash-table))
93
94(defmacro def-command-error-type (code name desc)
95 (let ((cond-sym (intern (concat "COMMAND-ERROR-" (symbol-name name)))))
96 `(progn (define-condition ,cond-sym (command-error)
97 ()
98 (:report (lambda (c s)
99 (format s "mpd error response: ~A (message was: `~A')" ,desc (command-error-message c)))))
100 (setf (gethash ,code *command-error-types*) ',cond-sym)
101 (export '(,cond-sym)))))
102;; The following are fetched from libmpdclient.h. In all honesty, I
103;; can't really figure out what they mean just from their names, so
104;; the descriptions aren't optimal in every conceivable way.
105(def-command-error-type 1 not-list "not list")
106(def-command-error-type 2 arg "argument")
107(def-command-error-type 3 password "bad password")
108(def-command-error-type 4 permission "permission denied")
109(def-command-error-type 5 unknown-cmd "unknown command")
110(def-command-error-type 50 no-exist "item does not exist")
111(def-command-error-type 51 playlist-max "playlist overload") ; ?!
112(def-command-error-type 52 system "system error")
113(def-command-error-type 53 playlist-load "could not load playlist")
114(def-command-error-type 54 update-already "already updated") ; ?!
115(def-command-error-type 55 player-sync "player sync") ; ?!
116(def-command-error-type 56 exist "item already exists")
117
118(export '(protocol-error reconnect command-error
119 protocol-error-retries command-error-code
120 command-error-message))
121
122;;; Struct definitions
123(defstruct song
124 (file "" :type string)
125 (id -1 :type integer)
126 (pos -1 :type integer)
127 (length -1 :type integer)
128 (track -1 :type integer)
129 artist title album genre composer date)
130
131(export '(song
132 song-file song-id song-pos song-length song-track
133 song-artist song-title song-album song-genre
134 song-composer song-date))
135
136(defstruct status
137 (volume 0 :type integer)
138 (playlist-version -1 :type integer)
139 (num-songs 0 :type integer)
140 (song -1 :type integer)
141 (songid -1 :type integer)
142 (pos -1 :type integer)
143 (song-len -1 :type integer)
144 repeat repeat-song random state)
145
146;;; Basic protocol management
147#+sbcl (defmacro with-conn-lock (&body body)
148 `(sb-thread:with-recursive-lock (*conn-lock*) ,@body))
149#-sbcl (defmacro with-conn-lock (&body body)
150 body)
151
152(defun disconnect ()
153 "Disconnect from MPD."
154 (with-conn-lock
155 (let ((sk (prog1 *socket* (setf *socket* nil))))
156 (if sk (ignore-errors (close sk))))))
157
158(defun connection-error (condition-type &rest condition-args)
159 (disconnect)
160 (error (apply #'make-condition condition-type :retries *retries* condition-args)))
161
162(defun command-error (code message)
163 (error (funcall #'make-condition (gethash code *command-error-types* 'command-error)
164 :err-code code
165 :message message)))
166
167(defun get-response ()
168 (let ((ret '()) (last nil))
169 (loop (let ((line (handler-case
170 (read-line *socket*)
171 (error (err)
172 (connection-error 'protocol-error
173 :message "Socket read error"
174 :cause err)))))
175 (regex-cond line
176 ("^OK( .*)?$"
177 ()
178 (return ret))
179 ("^ACK \\[(\\d+)@(\\d+)\\] \\{([^\\}]*)\\} (.*)$"
180 (code list-pos command rest)
181 (declare (ignore list-pos command))
182 (command-error (parse-integer code) rest))
183 ("^([^:]+): (.*)$"
184 (key val)
185 (let ((new (list (cons (intern (string-upcase key) (find-package 'keyword))
186 val))))
187 (if last
188 (setf (cdr last) new last new)
189 (setf ret new last new))))
190 (otherwise
191 (connection-error 'protocol-input-error
192 :message "Invalid response from mpd: ~A"
193 :inputs (list line))))))))
194
5a4158dd
FT
195(defun default-host ()
196 (block nil
197 #+sbcl (let ((host (sb-posix:getenv "MPD_HOST")))
198 (when host (return host)))
199 "localhost"))
200
201(defun default-port ()
202 (block nil
203 #+sbcl (let ((port (sb-posix:getenv "MPD_PORT")))
204 (when port (return (parse-integer port))))
205 6600))
206
207(defun connect (&key (host (default-host)) (port (default-port)))
9d561d5d
FT
208 "Connect to a running MPD."
209 (disconnect)
210 (with-conn-lock
211 (setf *socket* (block outer
212 (let ((last-err nil))
213 (dolist (address (host-ent-addresses (get-host-by-name host)))
214 (handler-case
215 (let ((sk (make-instance 'inet-socket :type :stream)))
216 (socket-connect sk address port)
217 (return-from outer (socket-make-stream sk :input t :output t :buffering :none)))
218 (error (err)
219 (setf last-err err)
220 (warn "mpd connection failure on address ~A: ~A" address err))))
221 (if last-err
222 (error "Could not connect to mpd: ~A" last-err)
223 (error "Could not connect to mpd: host name `~A' did not resolve to any addreses" host)))))
224 (setf *last-server* (cons host port))
225 (setf *last-command* (get-universal-time))
226 (get-response)))
227
228(defmacro dovector ((var vec) &body body)
229 (let ((i (gensym)))
230 `(dotimes (,i (length ,vec))
231 (let ((,var (aref ,vec ,i)))
232 ,@body))))
233
234(defmacro with-push-vector ((push-fun type &key (init-length 16)) &body body)
235 (let ((vec (gensym)))
236 `(let ((,vec (make-array (list ,init-length) :element-type ',type :adjustable t :fill-pointer 0)))
237 (flet ((,push-fun (el)
238 (declare (type ,type el))
239 (vector-push-extend el ,vec)))
240 ,@body)
241 ,vec)))
242
243(defun quote-argument (arg)
244 (declare (type string arg))
245 (if (= (length arg) 0)
246 "\"\""
247 (let* ((quote nil)
248 (res (with-push-vector (add character)
249 (dovector (elt arg)
250 (case elt
251 ((#\space #\tab)
252 (setf quote t) (add elt))
253 ((#\")
254 (setf quote t) (add #\\) (add #\"))
255 ((#\newline)
256 (error "Cannot send strings containing newlines to mpd: ~S" arg))
257 (t (add elt)))))))
258 (if quote
259 (concat "\"" res "\"")
260 res))))
261
262(defun arg-to-string (arg)
263 (quote-argument
264 (typecase arg
265 (string arg)
266 (t (write-to-string arg :escape nil)))))
267
268(defun mpd-command (&rest words)
269 (with-conn-lock
270 (let ((*retries* 0))
271 (loop
272 (restart-case
273 (progn (if (null *socket*)
274 (connection-error 'protocol-error
275 :message "Not connected to mpd"))
276 (handler-case
277 (progn (write-string (reduce #'(lambda (a b) (concat a " " b))
278 (mapcar #'arg-to-string words))
279 *socket*)
280 (terpri *socket*)
281 (force-output *socket*))
282 (error (err)
283 (connection-error 'protocol-error
284 :message "Socket write error"
285 :cause err)))
286 (setf *last-command* (get-universal-time))
287 (return (get-response)))
288 (reconnect ()
289 :test (lambda (c) (and (typep c 'protocol-error) (not (null *last-server*))))
290 :report (lambda (s)
291 (format s "Reconnect to ~A:~D and try again (~D retries so far)" (car *last-server*) (cdr *last-server*) *retries*))
292 (incf *retries*)
293 (connect :host (car *last-server*)
294 :port (cdr *last-server*))))))))
295
296(export '(connect disconnect))
297
298;;; Slot parsers
299;; These, and the structures themselves, should probably be rewritten
300;; using macros instead. There's a lot of redundancy.
301(defun cons-status (info)
302 (let ((ret (make-status)))
303 (dolist (line info ret)
304 (handler-case
305 (case (car line)
306 ((:time)
307 (let ((pos (assert-type '(integer 0 *) (position #\: (cdr line)))))
308 (setf (status-pos ret) (parse-integer (subseq (cdr line) 0 pos))
309 (status-song-len ret) (parse-integer (subseq (cdr line) (1+ pos))))))
310 ((:state) (setf (status-state ret) (intern (string-upcase (cdr line)) (find-package 'keyword))))
311 ((:repeat) (setf (status-repeat ret) (not (equal (cdr line) "0"))))
312 ((:repeatsong) (setf (status-repeat-song ret) (not (equal (cdr line) "0"))))
313 ((:random) (setf (status-random ret) (not (equal (cdr line) "0"))))
314 ((:volume) (setf (status-volume ret) (parse-integer (cdr line))))
315 ((:playlistlength) (setf (status-num-songs ret) (parse-integer (cdr line))))
316 ((:song) (setf (status-song ret) (parse-integer (cdr line))))
317 ((:songid) (setf (status-songid ret) (parse-integer (cdr line))))
318 ((:playlist) (setf (status-playlist-version ret) (parse-integer (cdr line))))
319 ;; Ignored:
320 ((:xfade :bitrate :audio))
321 (t (warn "Unknown status slot ~A" (car line))))
322 (parse-error ()
323 (warn "Status slot parse error in ~S, slot was ~S" ret line))))))
324
325(defun song-list (info)
326 (let ((ret '()) (cur nil))
327 (dolist (line info ret)
328 (handler-case
329 (case (car line)
330 ((:file)
331 (setf cur (make-song :file (cdr line)))
332 (setf ret (nconc ret (list cur))))
333 ((:time) (setf (song-length cur) (parse-integer (cdr line))))
334 ((:id) (setf (song-id cur) (parse-integer (cdr line))))
335 ((:pos) (setf (song-pos cur) (parse-integer (cdr line))))
336 ((:track) (setf (song-track cur) (parse-integer (cdr line))))
337 ((:title) (setf (song-title cur) (cdr line)))
338 ((:album) (setf (song-album cur) (cdr line)))
339 ((:artist) (setf (song-artist cur) (cdr line)))
340 ((:genre) (setf (song-genre cur) (cdr line)))
341 ((:composer) (setf (song-composer cur) (cdr line)))
342 ((:date) (setf (song-date cur) (cdr line)))
343 (t (warn "Unknown song slot ~A" (car line))))
344 (parse-error ()
345 (warn "Song slot parse error in ~A, slot was ~A" cur line))))))
346
347;;; Functions for individual commands
348(defun status ()
349 "Fetch and return the current status of the MPD as a STATUS structure."
350 (cons-status (mpd-command "status")))
351
352(defmacro with-status (slots &body body)
353 "Fetch the current status of the MPD, and then run BODY with the
354variables in the SLOTS bound to their curresponding status items.
355Available slots are:
356
357 STATE (SYMBOL)
358 The current state of the MPD
359 Known values are :STOP, :PAUSE and :PLAY
360 VOLUME (INTEGER 0 100)
361 Current output volume
362 PLAYLIST-VERSION (INTEGER 0 *)
363 Increases by one each time the playlist changes
364 NUM-SONGS (INTEGER 0 *)
365 Number of songs in the playlist
366 SONG (INTEGER 0 NUM-SONGS)
367 Index, in the playlist, of the currently playing song
368 SONGID (INTEGER)
369 ID of the currently playing song
370 SONG-LEN (INTEGER 0 *)
371 Length, in seconds, of currently playing song
372 POS (INTEGER 0 SONG-LEN)
373 Current time position of the currently playing song, in seconds
374 REPEAT (NIL or T)
375 Non-NIL if the MPD is in repeat mode
376 REPEAT-SONG (NIL or T)
377 Non-NIL if the MPD is repeating the current song
378 (not available without patching)
379 RANDOM (NIL or T)
380 Non-NIL if the MPD is in random mode"
381 (let ((status (gensym "STATUS")))
382 `(let* ((,status (status))
383 ;; This is kinda ugly, but I don't really know any better
384 ;; way to do it with structs.
385 ,@(mapcar #'(lambda (slot-sym)
386 (let ((slot-fun (intern (concat "STATUS-" (symbol-name slot-sym))
387 (find-package 'mpcl))))
388 `(,slot-sym (,slot-fun ,status))))
389 slots))
390 ,@body)))
391
392(defun play-song (song)
393 "Switch to a new song. SONG can be either an integer, indicating the
394position in the playlist of the song to be played, or a SONG structure
395instance (as received from the PLAYLIST function, for example),
396reflecting the song to be played."
397 (etypecase song
398 (song (mpd-command "playid" (song-id song)))
399 (integer (mpd-command "play" song))))
400
401(defun next ()
402 "Go to the next song in the playlist."
403 (mpd-command "next"))
404
405(defun prev ()
406 "Go to the previous song in the playlist."
407 (mpd-command "previous"))
408
409(defun toggle-pause ()
410 "Toggle between the :PAUSE and :PLAY states. Has no effect if the
411MPD is in the :STOP state."
412 (mpd-command "pause"))
413
414(defun pause ()
415 "Pause the playback, but only in the :PLAY state."
416 (if (eq (status-state (status)) :play)
417 (toggle-pause)))
418
419(defun ping ()
420 "Ping the MPD, so as to keep connection open."
421 (mpd-command "ping"))
422
423(defun maybe-ping ()
424 "Ping the MPD, but only if more than 10 seconds have elapsed since a
425command was last sent to it."
426 (if (and *socket*
427 (> (- (get-universal-time) *last-command*) 10))
428 (progn (ping) t)
429 nil))
430
431(defun stop ()
432 "Stop playback."
433 (mpd-command "stop"))
434
435(defun play ()
436 "Start playback of the current song."
437 (mpd-command "play"))
438
439(defun current-song ()
440 "Returns a SONG structure instance reflecting the currently playing song."
441 (first (song-list (mpd-command "currentsong"))))
442
443(defun song-info (song-num)
444 "Returns a SONG structure instance describing the song with the
445number SONG-NUM in the playlist"
446 (declare (type (integer 0 *) song-num))
447 (first (song-list (mpd-command "playlistinfo" song-num))))
448
449(defun playlist ()
450 "Return a list of SONG structure instances, reflecting the songs in
451the current playlist."
452 (song-list (mpd-command "playlistinfo")))
453
454(defun search-song (type datum)
455 "Search the entire song database for songs matching DATUM. TYPE
456specifies what data to search among, and can be one of the following
457symbols:
458
459 :ARTIST
460 :ALBUM
461 :TITLE
462 :TRACK
463 :GENRE
464 :COMPOSER
465 :PERFORMER
466 :COMMENT
467
468This function returns a list of SONG instances describing the search
469results, but meaningful information in the ID and POS slots, whether
470or not the songs are actually part of the current playlist."
471 (song-list (mpd-command "search" (string-downcase (symbol-name type)) datum)))
472
473(defun search-playlist (type datum)
474 "Works like the SEARCH-SONG function, but limits the search to the
475currently loaded playlist, and will return meaningful ID and POS
476information. See the documentation for the SEARCH-SONG function for
477further information."
478 (song-list (mpd-command "playlistsearch" (string-downcase (symbol-name type)) datum)))
479
480(defun seek (sec &optional relative)
481 "Seek in the currently playing song. If RELATIVE is NIL (the
482default), seeks to SEC seconds from the start; otherwise, seeks to SEC
483seconds from the current position (may be negative)."
484 (with-status (songid pos)
485 (if relative
486 (setf sec (+ pos sec)))
487 (mpd-command "seekid" songid sec)))
488
489(defun set-volume (value &optional relative)
490 "Tells the MPD to change the audio system volume to VALUE, ranging
491from 0 to 100. If RELATIVE is non-NIL, change the current volume by
492VALUE (which may be negative) instead."
493 (mpd-command "setvol"
494 (clipnum (if relative
495 (with-status (volume)
496 (+ volume value))
497 value)
498 0 100)))
499
500(export '(current-song song-info playlist status with-status ping maybe-ping
501 play-song next prev toggle-pause pause play stop seek set-volume
502 search-song search-playlist))
503(provide :mpcl)