modules/services_discovery/xcb_apps.c

   1 /**
   2  * @file xcb_apps.c
   3  * @brief List of application windows XCB module for VLC media player
   4  */
   5 /*****************************************************************************
   6  * Copyright © 2009 Rémi Denis-Courmont
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 2.1
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  ****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26 #include <stdarg.h>
  27 #include <xcb/xcb.h>
  28 typedef xcb_atom_t Atom;
  29 #include <X11/Xatom.h> /* XA_WINDOW */
  30 #include <vlc_common.h>
  31 #include <vlc_services_discovery.h>
  32 #include <vlc_dialog.h>
  33 #include <vlc_charset.h>
  34 #include <vlc_plugin.h>
  35 #include <poll.h>
  36 #include <search.h>
  37
  38 static int  Open (vlc_object_t *);
  39 static void Close (vlc_object_t *);
  40 static int vlc_sd_probe_Open (vlc_object_t *);
  41
  42 /*
  43  * Module descriptor
  44  */
  45 vlc_module_begin ()
  46     set_shortname (N_("Screen capture"))
  47     set_description (N_("Screen capture"))
  48     set_category (CAT_PLAYLIST)
  49     set_subcategory (SUBCAT_PLAYLIST_SD)
  50     set_capability ("services_discovery", 0)
  51     set_callbacks (Open, Close)
  52
  53     add_shortcut ("apps")
  54
  55     VLC_SD_PROBE_SUBMODULE
  56 vlc_module_end ()
  57
  58 struct services_discovery_sys_t
  59 {
  60     xcb_connection_t *conn;
  61     vlc_thread_t      thread;
  62     xcb_atom_t        net_client_list;
  63     xcb_atom_t        net_wm_name;
  64     xcb_window_t      root_window;
  65     void             *nodes;
  66 };
  67
  68 static void *Run (void *);
  69 static void Update (services_discovery_t *);
  70 static void DelItem (void *);
  71 static void AddDesktopItem(services_discovery_t *);
  72
  73 static int vlc_sd_probe_Open (vlc_object_t *obj)
  74 {
  75     vlc_probe_t *probe = (vlc_probe_t *)obj;
  76
  77     char *display = var_InheritString (obj, "x11-display");
  78     xcb_connection_t *conn = xcb_connect (display, NULL);
  79     free (display);
  80     if (xcb_connection_has_error (conn))
  81         return VLC_PROBE_CONTINUE;
  82     xcb_disconnect (conn);
  83     return vlc_sd_probe_Add (probe, "xcb_apps{longname=\"Screen capture\"}",
  84                              N_("Screen capture"), SD_CAT_MYCOMPUTER);
  85 }
  86
  87 /**
  88  * Probes and initializes.
  89  */
  90 static int Open (vlc_object_t *obj)
  91 {
  92     services_discovery_t *sd = (services_discovery_t *)obj;
  93     services_discovery_sys_t *p_sys = malloc (sizeof (*p_sys));
  94
  95     if (p_sys == NULL)
  96         return VLC_ENOMEM;
  97     sd->p_sys = p_sys;
  98
  99     /* Connect to X server */
 100     char *display = var_InheritString (obj, "x11-display");
 101     int snum;
 102     xcb_connection_t *conn = xcb_connect (display, &snum);
 103     free (display);
 104     if (xcb_connection_has_error (conn))
 105     {
 106         free (p_sys);
 107         return VLC_EGENERIC;
 108     }
 109     p_sys->conn = conn;
 110
 111     /* Find configured screen */
 112     const xcb_setup_t *setup = xcb_get_setup (conn);
 113     const xcb_screen_t *scr = NULL;
 114     for (xcb_screen_iterator_t i = xcb_setup_roots_iterator (setup);
 115          i.rem > 0; xcb_screen_next (&i))
 116     {
 117         if (snum == 0)
 118         {
 119             scr = i.data;
 120             break;
 121         }
 122         snum--;
 123     }
 124     if (scr == NULL)
 125     {
 126         msg_Err (obj, "bad X11 screen number");
 127         goto error;
 128     }
 129
 130     /* Add a permanent item for the entire desktop */
 131     AddDesktopItem (sd);
 132
 133     p_sys->root_window = scr->root;
 134     xcb_change_window_attributes (conn, scr->root, XCB_CW_EVENT_MASK,
 135                                &(uint32_t) { XCB_EVENT_MASK_PROPERTY_CHANGE });
 136
 137     /* TODO: check that _NET_CLIENT_LIST is in _NET_SUPPORTED
 138      * (and _NET_SUPPORTING_WM_CHECK) */
 139     xcb_intern_atom_reply_t *r;
 140     xcb_intern_atom_cookie_t ncl, nwn;
 141
 142     ncl = xcb_intern_atom (conn, 1, strlen ("_NET_CLIENT_LIST"),
 143                           "_NET_CLIENT_LIST");
 144     nwn = xcb_intern_atom (conn, 0, strlen ("_NET_WM_NAME"), "_NET_WM_NAME");
 145
 146     r = xcb_intern_atom_reply (conn, ncl, NULL);
 147     if (r == NULL || r->atom == 0)
 148     {
 149         dialog_Fatal (sd, _("Screen capture"),
 150             _("Your window manager does not provide a list of applications."));
 151         msg_Err (sd, "client list not supported (_NET_CLIENT_LIST absent)");
 152     }
 153     p_sys->net_client_list = r ? r->atom : 0;
 154     free (r);
 155     r = xcb_intern_atom_reply (conn, nwn, NULL);
 156     if (r != NULL)
 157     {
 158         p_sys->net_wm_name = r->atom;
 159         free (r);
 160     }
 161
 162     p_sys->nodes = NULL;
 163     Update (sd);
 164
 165     if (vlc_clone (&p_sys->thread, Run, sd, VLC_THREAD_PRIORITY_LOW))
 166         goto error;
 167     return VLC_SUCCESS;
 168
 169 error:
 170     xcb_disconnect (p_sys->conn);
 171     free (p_sys);
 172     return VLC_EGENERIC;
 173 }
 174
 175
 176 /**
 177  * Releases resources
 178  */
 179 static void Close (vlc_object_t *obj)
 180 {
 181     services_discovery_t *sd = (services_discovery_t *)obj;
 182     services_discovery_sys_t *p_sys = sd->p_sys;
 183
 184     vlc_cancel (p_sys->thread);
 185     vlc_join (p_sys->thread, NULL);
 186     xcb_disconnect (p_sys->conn);
 187     tdestroy (p_sys->nodes, DelItem);
 188     free (p_sys);
 189 }
 190
 191 static void *Run (void *data)
 192 {
 193     services_discovery_t *sd = data;
 194     services_discovery_sys_t *p_sys = sd->p_sys;
 195     xcb_connection_t *conn = p_sys->conn;
 196     int fd = xcb_get_file_descriptor (conn);
 197     if (fd == -1)
 198         return NULL;
 199
 200     while (!xcb_connection_has_error (conn))
 201     {
 202         xcb_generic_event_t *ev;
 203         struct pollfd ufd = { .fd = fd, .events = POLLIN, };
 204
 205         poll (&ufd, 1, -1);
 206
 207         int canc = vlc_savecancel ();
 208         while ((ev = xcb_poll_for_event (conn)) != NULL)
 209         {
 210             if ((ev->response_type & 0x7F) == XCB_PROPERTY_NOTIFY)
 211             {
 212                  const xcb_property_notify_event_t *pn =
 213                      (xcb_property_notify_event_t *)ev;
 214                  if (pn->atom == p_sys->net_client_list)
 215                      Update (sd);
 216             }
 217             free (ev);
 218         }
 219         vlc_restorecancel (canc);
 220     }
 221     return NULL;
 222 }
 223
 224 struct app
 225 {
 226     xcb_window_t          xid; /* must be first for cmpapp */
 227     input_item_t         *item;
 228     services_discovery_t *owner;
 229 };
 230
 231 static struct app *AddItem (services_discovery_t *sd, xcb_window_t xid)
 232 {
 233     services_discovery_sys_t *p_sys = sd->p_sys;
 234     char *mrl, *name;
 235
 236     if (asprintf (&mrl, "window://0x%"PRIx8, xid) == -1)
 237         return NULL;
 238
 239     xcb_get_property_reply_t *r =
 240         xcb_get_property_reply (p_sys->conn,
 241             xcb_get_property (p_sys->conn, 0, xid, p_sys->net_wm_name, 0,
 242                               0, 1023 /* max size */), NULL);
 243     if (r != NULL)
 244     {
 245         name = strndup (xcb_get_property_value (r),
 246                         xcb_get_property_value_length (r));
 247         if (name != NULL)
 248             EnsureUTF8 (name); /* don't trust third party apps too much ;-) */
 249         free (r);
 250     }
 251     /* TODO: use WM_NAME (Latin-1) for very old apps */
 252     else
 253         name = NULL;
 254
 255     input_item_t *item = input_item_NewWithType (VLC_OBJECT (sd), mrl,
 256                                                  name ? name : mrl,
 257                                                  0, NULL, 0, -1,
 258                                                  ITEM_TYPE_CARD /* FIXME */);
 259     free (mrl);
 260     free (name);
 261     if (item == NULL)
 262         return NULL;
 263
 264     struct app *app = malloc (sizeof (*app));
 265     if (app == NULL)
 266     {
 267         vlc_gc_decref (item);
 268         return NULL;
 269     }
 270     app->xid = xid;
 271     app->item = item;
 272     app->owner = sd;
 273     services_discovery_AddItem (sd, item, _("Applications"));
 274     return app;
 275 }
 276
 277 static void DelItem (void *data)
 278 {
 279     struct app *app = data;
 280
 281     services_discovery_RemoveItem (app->owner, app->item);
 282     vlc_gc_decref (app->item);
 283     free (app);
 284 }
 285
 286 static int cmpapp (const void *a, const void *b)
 287 {
 288     xcb_window_t wa = *(xcb_window_t *)a;
 289     xcb_window_t wb = *(xcb_window_t *)b;
 290
 291     if (wa > wb)
 292         return 1;
 293     if (wa < wb)
 294         return -1;
 295     return 0;
 296 }
 297
 298 static void Update (services_discovery_t *sd)
 299 {
 300     services_discovery_sys_t *p_sys = sd->p_sys;
 301     xcb_connection_t *conn = p_sys->conn;
 302
 303     xcb_get_property_reply_t *r =
 304         xcb_get_property_reply (conn,
 305             xcb_get_property (conn, false, p_sys->root_window,
 306                               p_sys->net_client_list, XA_WINDOW, 0, 1024),
 307             NULL);
 308     if (r == NULL)
 309         return; /* FIXME: remove all entries */
 310
 311     xcb_window_t *ent = xcb_get_property_value (r);
 312     int n = xcb_get_property_value_length (r) / 4;
 313     void *newnodes = NULL, *oldnodes = p_sys->nodes;
 314
 315     for (int i = 0; i < n; i++)
 316     {
 317         xcb_window_t id = *(ent++);
 318         struct app *app;
 319
 320         struct app **pa = tfind (&id, &oldnodes, cmpapp);
 321         if (pa != NULL) /* existing entry */
 322         {
 323             app = *pa;
 324             tdelete (app, &oldnodes, cmpapp);
 325         }
 326         else /* new entry */
 327         {
 328             app = AddItem (sd, id);
 329             if (app == NULL)
 330                 continue;
 331         }
 332
 333         pa = tsearch (app, &newnodes, cmpapp);
 334         if (pa == NULL /* OOM */ || *pa != app /* buggy window manager */)
 335             DelItem (app);
 336     }
 337     free (r);
 338
 339     /* Remove old nodes */
 340     tdestroy (oldnodes, DelItem);
 341     p_sys->nodes = newnodes;
 342 }
 343
 344 static void AddDesktopItem(services_discovery_t *sd)
 345 {
 346     input_item_t *item;
 347
 348     item = input_item_NewWithType (VLC_OBJECT (sd), "screen://", _("Desktop"),
 349                                    0, NULL, 0, -1, ITEM_TYPE_CARD);
 350     if (item == NULL)
 351         return;
 352
 353     services_discovery_AddItem (sd, item, NULL);
 354 }