mmd: rename dbinfo to selector_info
[paraslash.git] / playlist_selector.c
1 /*
2 * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /** \file playlist_selector.c The playlist audio file selector of paraslash */
20
21 #include "server.h"
22 #include "db.h"
23 #include "error.h"
24 #include "net.h"
25 #include "string.h"
26 #include "ipc.h"
27
28 /**
29 * structure used for transmission of the playlist
30 *
31 * There's one such struct which gets initialized during startup. It lives in
32 * shared memory and is used by com_lpl().
33 */
34 struct pls_client_data {
35 /** allocated and set by com_lpl() (child) */
36 int shm_id;
37 /** the size of the shared memory area identified by \a shm_id */
38 size_t size;
39 /** initially locked, gets unlocked by parent when it is done */
40 int mutex;
41 /** return value, set by parent */
42 int retval;
43 };
44
45 /** data specific to the playlist selector */
46 struct private_pls_data {
47 /** guards against concurrent client access */
48 int client_mutex;
49 /** guards against concurrent parent-child access */
50 int server_mutex;
51 /** pointer to the client data */
52 struct pls_client_data *client_data;
53 /** id of the shm corresponding to \a client_data */
54 int client_data_shm_id;
55 };
56
57 /** we refuse to load playlists bigger than that */
58 #define MAX_PLAYLIST_BYTES (1024 * 1024)
59
60 static unsigned playlist_len, playlist_size, current_playlist_entry;
61 static char **playlist;
62 static struct audio_file_selector *self;
63
64 static int com_ppl(int, int, char **);
65 static int com_lpl(int, int, char **);
66 extern struct misc_meta_data *mmd;
67
68 /* array of supported commands */
69 static struct server_command cmds[] = {
70 {
71 .name = "ppl",
72 .handler = com_ppl,
73 .perms = DB_READ,
74 .description = "print playlist",
75 .synopsis = "ppl",
76 .help =
77 "Print out the current playlist"
78 }, {
79 .name = "lpl",
80 .handler = com_lpl,
81 .perms = DB_WRITE,
82 .description = "load playlist",
83 .synopsis = "lpl",
84 .help =
85 "Read a new playlist from stdin. Example:\n"
86 "\tfind /audio -name '*.mp3' | para_client lpl"
87 }, {
88 .name = NULL,
89 }
90 };
91
92 static void playlist_add(char *path)
93 {
94 if (playlist_len >= playlist_size) {
95 playlist_size = 2 * playlist_size + 1;
96 playlist = para_realloc(playlist, playlist_size * sizeof(char *));
97 }
98 PARA_DEBUG_LOG("adding #%d/%d: %s\n", playlist_len, playlist_size, path);
99 playlist[playlist_len++] = para_strdup(path);
100 }
101
102 static int send_playlist_to_server(const char *buf, size_t size)
103 {
104 struct private_pls_data *ppd = self->private_data;
105 int ret, shm_mutex = -1, shm_id = -1;
106 void *shm = NULL;
107
108 PARA_DEBUG_LOG("new playlist (%d bytes)\n", size);
109
110 ret = mutex_new();
111 if (ret < 0)
112 return ret;
113 shm_mutex = ret;
114
115 ret = shm_new(size);
116 if (ret < 0)
117 goto out;
118 shm_id = ret;
119
120 ret = shm_attach(shm_id, ATTACH_RW, &shm);
121 if (ret < 0)
122 goto out;
123 mutex_lock(shm_mutex);
124 memcpy(shm, buf, size);
125 mutex_lock(ppd->client_mutex);
126 mutex_lock(ppd->server_mutex);
127 ppd->client_data->size = size;
128 ppd->client_data->shm_id = shm_id;
129 ppd->client_data->mutex = shm_mutex;
130 kill(getppid(), SIGUSR1); /* wake up the server */
131 mutex_unlock(ppd->server_mutex);
132 mutex_lock(shm_mutex); /* wait until server is done */
133 mutex_unlock(shm_mutex);
134 ret = ppd->client_data->retval;
135 mutex_unlock(ppd->client_mutex);
136 shm_detach(shm);
137 out:
138 if (shm_id >= 0)
139 shm_destroy(shm_id);
140 mutex_destroy(shm_mutex);
141 PARA_DEBUG_LOG("returning %d\n", ret);
142 return ret;
143 }
144
145 static int com_lpl(int fd, __unused int argc, __unused char *argv[])
146 {
147 unsigned loaded = 0;
148 size_t bufsize = 4096; /* guess that's enough */
149 char *buf = para_malloc(bufsize);
150 ssize_t ret;
151 ret = send_buffer(fd, AWAITING_DATA_MSG);
152 if (ret < 0)
153 goto out;
154 again:
155 ret = recv_bin_buffer(fd, buf + loaded, bufsize - loaded);
156 if (ret < 0)
157 goto out;
158 if (!ret) {
159 ret = send_playlist_to_server(buf, loaded);
160 goto out;
161 }
162 loaded += ret;
163 ret = -E_LOAD_PLAYLIST;
164 if (loaded >= MAX_PLAYLIST_BYTES)
165 goto out;
166 if (loaded >= bufsize) {
167 bufsize *= 2;
168 buf = para_realloc(buf, bufsize);
169 }
170 goto again;
171 out:
172 free(buf);
173 return ret;
174 }
175
176 static int com_ppl(int fd, __unused int argc, __unused char *argv[])
177 {
178 unsigned i;
179
180 PARA_DEBUG_LOG("sending playlist to client (%d entries)\n", playlist_len);
181 for (i = 0; i < playlist_len; i++) {
182 int ret = send_va_buffer(fd, "%s\n", playlist[
183 (i + current_playlist_entry) % playlist_len]);
184 if (ret < 0)
185 return ret;
186 }
187 return 1;
188 }
189
190 static char **pls_get_audio_file_list(unsigned int num)
191 {
192 char **file_list;
193 unsigned i;
194
195 num = MIN(num, playlist_len);
196 if (!num)
197 return NULL;
198 file_list = para_malloc((num + 1) * sizeof(char *));
199 for (i = 0; i < num; i++) {
200 unsigned j = (current_playlist_entry + i) % playlist_len;
201 file_list[i] = para_strdup(playlist[j]);
202 }
203 file_list[i] = NULL;
204 return file_list;
205 }
206
207 static void free_playlist_contents(void)
208 {
209 int i;
210
211 PARA_DEBUG_LOG("freeing playlist (%d entries)\n", playlist_len);
212 for (i = 0; i < playlist_len; i++)
213 free(playlist[i]);
214 current_playlist_entry = 0;
215 playlist_len = 0;
216 }
217
218 static void pls_shutdown(void)
219 {
220 struct private_pls_data *ppd = self->private_data;
221
222 shm_detach(ppd->client_data);
223 shm_destroy(ppd->client_data_shm_id);
224 mutex_destroy(ppd->server_mutex);
225 mutex_destroy(ppd->client_mutex);
226 free(ppd);
227 free_playlist_contents();
228 free(playlist);
229 playlist = NULL;
230 playlist_len = 0;
231 playlist_size = 0;
232 }
233
234 static void pls_post_select(__unused fd_set *rfds, __unused fd_set *wfds)
235 {
236 struct private_pls_data *ppd = self->private_data;
237 struct pls_client_data *pcd = ppd->client_data;
238 int ret;
239 void *shm;
240
241 mutex_lock(ppd->server_mutex);
242 if (!pcd->size)
243 goto out;
244 free_playlist_contents();
245 ret = shm_attach(pcd->shm_id, ATTACH_RW, &shm);
246 if (ret < 0) {
247 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
248 goto out;
249 }
250 PARA_DEBUG_LOG("loading new playlist (%d bytes)\n", pcd->size);
251 ret = for_each_line((char *)shm, pcd->size, &playlist_add);
252 shm_detach(shm);
253 PARA_NOTICE_LOG("new playlist (%d entries)\n", playlist_len);
254 pcd->retval = 1;
255 pcd->size = 0;
256 mutex_unlock(pcd->mutex);
257 out:
258 mutex_unlock(ppd->server_mutex);
259 }
260
261 void pls_update_audio_file(char *audio_file)
262 {
263 unsigned i;
264
265 for (i = 0; i < playlist_len; i++) {
266 unsigned j = (current_playlist_entry + i) % playlist_len;
267 if (strcmp(playlist[j], audio_file))
268 continue;
269 current_playlist_entry = (j + 1) % playlist_len;
270 }
271 }
272
273 /**
274 * the init function for the playlist selector
275 *
276 * Init all function pointers of \a db
277 *
278 * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
279 * random_selector.c.
280 */
281 int playlist_selector_init(struct audio_file_selector *db)
282 {
283 int ret;
284 struct private_pls_data *ppd = NULL;
285 void *shm = NULL;
286
287 self = db;
288 db->cmd_list = cmds;
289 db->get_audio_file_list = pls_get_audio_file_list;
290 db->shutdown = pls_shutdown;
291 db->post_select = pls_post_select;
292 db->update_audio_file = pls_update_audio_file;
293 ppd = para_calloc(sizeof(struct private_pls_data));
294 db->private_data = ppd;
295
296 ppd->client_mutex = -1;
297 ppd->server_mutex = -1;
298 ppd->client_data_shm_id = -1;
299 ppd->client_data = NULL;
300
301 ret = mutex_new();
302 if (ret < 0)
303 goto err_out;
304 ppd->client_mutex = ret;
305
306 ret = mutex_new();
307 if (ret < 0)
308 goto err_out;
309 ppd->server_mutex = ret;
310
311 ret = shm_new(sizeof(struct pls_client_data));
312 if (ret < 0)
313 goto err_out;
314 ppd->client_data_shm_id = ret;
315
316 ret = shm_attach(ppd->client_data_shm_id, ATTACH_RW, &shm);
317 if (ret < 0)
318 goto err_out;
319 ppd->client_data = shm;
320 ppd->client_data->size = 0;
321 sprintf(mmd->selector_info, "playlist selector initialized");
322 return 1;
323 err_out:
324 if (ppd->client_data_shm_id >= 0)
325 shm_destroy(ppd->client_data_shm_id);
326 if (ppd->client_mutex >= 0)
327 mutex_destroy(ppd->client_mutex);
328 if (ppd->server_mutex >= 0)
329 mutex_destroy(ppd->server_mutex);
330 free(ppd);
331 return ret;
332 }