src/lua.c

   1 /* Lua scripting support
   2  *
   3  * Copyright (c) 2008 Sadrul Habib Chowdhury (sadrul@users.sf.net)
   4  * Copyright (c) 2009
   5  *      Sadrul Habib Chowdhury (sadrul@users.sf.net)
   6  *      Rui Guo (firemeteor.guo@gmail.com)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3, or (at your option)
  11  * any later version.
  12  *
  13  * This program 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 General Public License
  19  * along with this program (see the file COPYING); if not, write to the
  20  * Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
  22  *
  23  ****************************************************************
  24  */
  25 #include <sys/types.h>
  26 #include "config.h"
  27 #include "screen.h"
  28 #include <sys/stat.h>
  29 #include <unistd.h>
  30
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <stdlib.h>
  34
  35 #include "extern.h"
  36 #include "logfile.h"
  37
  38 #include <lua.h>
  39 #include <lauxlib.h>
  40 #include <lualib.h>
  41
  42 static int StackDump(lua_State *L, const char *message)
  43 {
  44   FILE *f = fopen("/tmp/debug/stack", "ab");
  45   int i = lua_gettop(L);
  46   if (message)
  47     fprintf(f, "%s", message);
  48   while (i)
  49     {
  50       int t = lua_type(L, i);
  51       switch (t)
  52         {
  53           case LUA_TSTRING:
  54             fprintf(f, "String: %s\n", lua_tostring(L, i));
  55             break;
  56
  57           case LUA_TBOOLEAN:
  58             fprintf(f, "Boolean: %s\n", lua_toboolean(L, i) ? "true" : "false");
  59             break;
  60
  61           case LUA_TNUMBER:
  62             fprintf(f, "Number: %g\n", lua_tonumber(L, i));
  63             break;
  64
  65           default:
  66             fprintf(f, "Type: %s\n", lua_typename(L, t));
  67         }
  68       i--;
  69     }
  70   if (message)
  71     fprintf(f, "----\n");
  72   fclose(f);
  73   return 0;
  74 }
  75
  76 extern struct win *windows, *fore;
  77 extern struct display *displays, *display;
  78 extern struct LayFuncs WinLf;
  79 extern struct layer *flayer;
  80 extern void AppendWinMsgRend(const char *str, const char *color);
  81 extern void FocusCanvas(struct canvas *cv);
  82
  83 static int LuaDispatch(void *handler, const char *params, va_list va);
  84 static int LuaRegEvent(lua_State *L);
  85 static void LuaShowErr(lua_State *L);
  86 struct binding lua_binding;
  87
  88 enum
  89 {
  90   LUA_HANDLER_TYPE_N = 1,
  91   LUA_HANDLER_TYPE_F
  92 };
  93
  94 struct lua_handler
  95 {
  96   int type;
  97   lua_State *L;
  98   union
  99   {
 100     const char *name;
 101     int reference;
 102   } u;
 103 };
 104
 105 typedef struct lua_handler *lua_handler;
 106 void LuaPushHandler(lua_handler lh);
 107 void LuaHUnRef(lua_State *L, int key);
 108 lua_handler LuaCheckHandler(lua_State *L, int idx, int ref);
 109
 110 lua_handler
 111 LuaAllocHandler(lua_State *L, const char *name, int ref)
 112 {
 113   struct lua_handler *lh;
 114   lh = (struct lua_handler*) malloc(sizeof(struct lua_handler));
 115   if (!lh)
 116     return NULL;
 117
 118   lh->L = L;
 119   if (name)
 120     {
 121       lh->type = LUA_HANDLER_TYPE_N;
 122       lh->u.name = SaveStr(name);
 123     }
 124   else
 125     {
 126       lh->type = LUA_HANDLER_TYPE_F;
 127       lh->u.reference = ref;
 128     }
 129
 130   return lh;
 131 }
 132
 133 void
 134 LuaFreeHandler(lua_State *L, struct lua_handler **lh)
 135 {
 136   if ((*lh)->type == LUA_HANDLER_TYPE_N)
 137     Free((*lh)->u.name)
 138   else if (L)
 139     {
 140       LuaHUnRef(L, (*lh)->u.reference);
 141       (*lh)->u.reference = 0;
 142     }
 143   Free(*lh);
 144 }
 145
 146 struct sfile {
 147     lua_State *L;
 148     ino_t inode;
 149     int inuse;
 150     struct sfile *next;
 151 };
 152
 153 struct sfile *scripts = NULL;
 154
 155 struct sfile *
 156 LuaGetSFile(lua_State *L)
 157 {
 158   struct sfile *slist;
 159   luaL_getmetatable(L, "screen");
 160   lua_pushstring(L, "_sfile");
 161   lua_rawget(L, -2);
 162   slist = (struct sfile *)lua_touserdata(L, -1);
 163   lua_pop(L, 2);
 164   return slist;
 165 }
 166
 167 /** Template {{{ */
 168
 169 #define CHECK_TYPE(name, type) \
 170 static type * \
 171 check_##name(lua_State *L, int index) \
 172 { \
 173   struct broker **broker; \
 174   type *var; \
 175   luaL_checktype(L, index, LUA_TUSERDATA); \
 176   broker = (struct broker **) luaL_checkudata(L, index, #name); \
 177   if (broker) { \
 178       var = (type *)get_broker_obj(broker); \
 179   } \
 180   if (!broker || !*broker) \
 181     luaL_typerror(L, index, #name); \
 182   return var; \
 183 }
 184
 185 #define PUSH_TYPE(name, type) \
 186 static void \
 187 push_##name(lua_State *L, type **t) \
 188 { \
 189   if (!t || !*t) \
 190     lua_pushnil(L); \
 191   else \
 192     { \
 193       struct broker **r; \
 194       r = (struct broker **)lua_newuserdata(L, sizeof(struct broker *)); \
 195       *r = get_obj_broker(*t); \
 196       luaL_getmetatable(L, #name); \
 197       lua_setmetatable(L,-2); \
 198     } \
 199 }
 200
 201 /* Much of the following template comes from:
 202  *      http://lua-users.org/wiki/BindingWithMembersAndMethods
 203  */
 204
 205 static int get_int (lua_State *L, void *v)
 206 {
 207   lua_pushinteger (L, *(int*)v);
 208   return 1;
 209 }
 210
 211 static int set_int (lua_State *L, void *v)
 212 {
 213   *(int*)v = luaL_checkint(L, 3);
 214   return 0;
 215 }
 216
 217 static int get_number (lua_State *L, void *v)
 218 {
 219   lua_pushnumber(L, *(lua_Number*)v);
 220   return 1;
 221 }
 222
 223 static int set_number (lua_State *L, void *v)
 224 {
 225   *(lua_Number*)v = luaL_checknumber(L, 3);
 226   return 0;
 227 }
 228
 229 static int get_string (lua_State *L, void *v)
 230 {
 231   lua_pushstring(L, (char*)v );
 232   return 1;
 233 }
 234
 235 static int set_string (lua_State *L, void *v)
 236 {
 237   *(const char**)v = luaL_checkstring(L, 3);
 238   return 0;
 239 }
 240
 241 typedef int (*Xet_func) (lua_State *L, void *v);
 242
 243 /* member info for get and set handlers */
 244 struct Xet_reg
 245 {
 246   const char *name;  /* member name */
 247   Xet_func func;     /* get or set function for type of member */
 248   size_t offset;     /* offset of member within the struct */
 249   int (*absolute)(lua_State *);
 250 };
 251
 252 static void Xet_add (lua_State *L, const struct Xet_reg *l)
 253 {
 254   if (!l)
 255     return;
 256   for (; l->name; l++)
 257     {
 258       lua_pushstring(L, l->name);
 259       lua_pushlightuserdata(L, (void*)l);
 260       lua_settable(L, -3);
 261     }
 262 }
 263
 264 static int Xet_call (lua_State *L)
 265 {
 266   /* for get: stack has userdata, index, lightuserdata */
 267   /* for set: stack has userdata, index, value, lightuserdata */
 268   const struct Xet_reg *m = (const struct Xet_reg *)lua_touserdata(L, -1);  /* member info */
 269   void *obj;
 270   lua_pop(L, 1);                               /* drop lightuserdata */
 271   luaL_checktype(L, 1, LUA_TUSERDATA);
 272   if (m->absolute)
 273     return m->absolute(L);
 274   obj = get_broker_obj((struct broker **)lua_touserdata(L, 1));
 275   return m->func(L, (char *)obj + m->offset);
 276 }
 277
 278 static int index_handler (lua_State *L)
 279 {
 280   /* stack has userdata, index */
 281   lua_pushvalue(L, 2);                     /* dup index */
 282   lua_rawget(L, lua_upvalueindex(1));      /* lookup member by name */
 283   if (!lua_islightuserdata(L, -1))
 284     {
 285       lua_pop(L, 1);                         /* drop value */
 286       lua_pushvalue(L, 2);                   /* dup index */
 287       lua_gettable(L, lua_upvalueindex(2));  /* else try methods */
 288       if (lua_isnil(L, -1))                  /* invalid member */
 289         luaL_error(L, "cannot get member '%s'", lua_tostring(L, 2));
 290       return 1;
 291     }
 292   return Xet_call(L);                      /* call get function */
 293 }
 294
 295 static int newindex_handler (lua_State *L)
 296 {
 297   /* stack has userdata, index, value */
 298   lua_pushvalue(L, 2);                     /* dup index */
 299   lua_rawget(L, lua_upvalueindex(1));      /* lookup member by name */
 300   if (!lua_islightuserdata(L, -1))         /* invalid member */
 301     luaL_error(L, "cannot set member '%s'", lua_tostring(L, 2));
 302   return Xet_call(L);                      /* call set function */
 303 }
 304
 305 static int
 306 struct_register(lua_State *L, const char *name, const luaL_reg fn_methods[], const luaL_reg meta_methods[],
 307     const struct Xet_reg setters[], const struct Xet_reg getters[])
 308 {
 309   int metatable, methods;
 310
 311   /* create methods table & add it to the table of globals */
 312   luaL_register(L, name, fn_methods);
 313   methods = lua_gettop(L);
 314
 315   /* create metatable & add it to the registry */
 316   luaL_newmetatable(L, name);
 317   luaL_register(L, 0, meta_methods);  /* fill metatable */
 318
 319   /* To identify the type of object */
 320   lua_pushstring(L, "_objname");
 321   lua_pushstring(L, name);
 322   lua_rawset(L, -3);
 323
 324   metatable = lua_gettop(L);
 325
 326   lua_pushliteral(L, "__metatable");
 327   lua_pushvalue(L, methods);    /* dup methods table*/
 328   lua_rawset(L, metatable);     /* hide metatable:
 329                                    metatable.__metatable = methods */
 330
 331   lua_pushliteral(L, "__index");
 332   lua_pushvalue(L, metatable);  /* upvalue index 1 */
 333   Xet_add(L, getters);     /* fill metatable with getters */
 334   lua_pushvalue(L, methods);    /* upvalue index 2 */
 335   lua_pushcclosure(L, index_handler, 2);
 336   lua_rawset(L, metatable);     /* metatable.__index = index_handler */
 337
 338   lua_pushliteral(L, "__newindex");
 339   lua_newtable(L);              /* table for members you can set */
 340   Xet_add(L, setters);     /* fill with setters */
 341   lua_pushcclosure(L, newindex_handler, 1);
 342   lua_rawset(L, metatable);     /* metatable.__newindex = newindex_handler */
 343
 344   /* FIXME: Why do we leave an element on the stack? */
 345   lua_pop(L, 1);                /* drop metatable */
 346   return 1;                     /* return methods on the stack */
 347 }
 348
 349 /** }}} */
 350
 351 /** Callback {{{ */
 352 static void
 353 push_callback(lua_State *L, struct listener **t)
 354 {
 355   if (!t || !*t)
 356     lua_pushnil(L);
 357   else
 358     {
 359       struct listener **r;
 360       r = (struct listener **)lua_newuserdata(L, sizeof(struct listener *));
 361       *r = *t;
 362       luaL_getmetatable(L, "callback");
 363       lua_setmetatable(L,-2);
 364     }
 365 }
 366
 367
 368 static int
 369 internal_unhook(lua_State *L, int warn)
 370 {
 371   /*Emulate check_callback() */
 372   struct listener **ppl;
 373   luaL_checktype(L, 1, LUA_TUSERDATA);
 374   ppl = (struct listener **) luaL_checkudata(L, 1, "callback");
 375
 376   if (!ppl)
 377     luaL_typerror(L, 1, "callback");
 378
 379   if (!*ppl)
 380     {
 381       if (warn)
 382         {
 383           lua_pushboolean(L, 0);
 384           lua_pushstring(L, "Callback already unhooked.");
 385           LuaShowErr(L);
 386         }
 387     }
 388   else
 389     {
 390       LuaFreeHandler(L, (lua_handler *)&(*ppl)->handler);
 391       unregister_listener(*ppl);
 392       *ppl = 0;
 393       if (warn)
 394         lua_pushboolean(L, 1);
 395     }
 396   return warn != 0;
 397 }
 398 static int
 399 callback_unhook(lua_State *L)
 400 {
 401   return internal_unhook(L, 1);
 402 }
 403
 404 static const luaL_reg callback_methods[] = {
 405   {"unhook", callback_unhook},
 406   {0, 0}
 407 };
 408
 409 int
 410 callback_collect(lua_State *L)
 411 {
 412   return internal_unhook(L, 0);
 413 }
 414
 415 static const luaL_reg callback_metamethods[] = {
 416   {"__gc", callback_collect},
 417   {0, 0}
 418 };
 419
 420 static const struct Xet_reg callback_setters[] = {
 421   {0, 0}
 422 };
 423
 424 static const struct Xet_reg callback_getters[] = {
 425   {0, 0}
 426 };
 427
 428
 429 /** }}} */
 430
 431 static int
 432 screen_object_collect(lua_State *L)
 433 {
 434   struct broker **pbroker;
 435   luaL_checktype(L, 1, LUA_TUSERDATA);
 436   pbroker = (struct broker **)lua_touserdata(L, 1);
 437   broker_unref(pbroker);
 438   return 0;
 439 }
 440
 441 /** Window {{{ */
 442
 443 PUSH_TYPE(window, struct win)
 444
 445 CHECK_TYPE(window, struct win)
 446
 447 static int get_window(lua_State *L, void *v)
 448 {
 449   push_window(L, (struct win **)v);
 450   return 1;
 451 }
 452
 453 static int
 454 window_change_title(lua_State *L)
 455 {
 456   struct win *w = check_window(L, 1);
 457   unsigned int len;
 458   const char *title = luaL_checklstring(L, 3, &len);
 459   ChangeAKA(w, (char *)title, len);
 460   return 0;
 461 }
 462
 463 static int
 464 window_change_number(lua_State *L)
 465 {
 466   struct win *w = check_window(L, 1);
 467   int newnum = luaL_checkint(L, 3);
 468   ChangeWinNum(w->w_number, newnum);
 469   return 0;
 470 }
 471
 472 static int
 473 window_get_monitor_status(lua_State *L)
 474 {
 475   struct win *w = check_window(L, 1);
 476   int activity = luaL_checkint(L, 2);
 477   if (activity)
 478     /*monitor*/
 479     lua_pushinteger(L, w->w_monitor != MON_OFF);
 480   else
 481     /*silence*/
 482     lua_pushinteger(L, w->w_silence == SILENCE_ON ? w->w_silencewait: 0);
 483
 484   return 1;
 485 }
 486
 487 static int
 488 window_stuff(lua_State *L)
 489 {
 490   unsigned int len;
 491   struct layer *oldflayer = flayer;
 492   struct win *w = check_window(L, 1);
 493   const char *str = luaL_checklstring(L, 2, &len);
 494
 495   flayer = &w->w_layer;
 496   while(len)
 497     LayProcess((char **)&str, (int *) &len);
 498   flayer = oldflayer;
 499   return 0;
 500 }
 501
 502 static int
 503 window_activate(lua_State *L)
 504 {
 505   struct win *w = check_window(L, 1);
 506   SetForeWindow(w);
 507   return 0;
 508 }
 509
 510 static void push_canvas(lua_State *L, struct canvas **t);
 511
 512 static int
 513 window_get_showing_canvases(lua_State *L)
 514 {
 515   struct win *w = check_window(L, 1);
 516   int count = 0;
 517   struct canvas *cv = w->w_layer.l_cvlist;
 518   if (!cv) {
 519       lua_pushnil(L);
 520       return 1;
 521   }
 522   lua_newtable(L);
 523   while (cv) {
 524     lua_pushinteger(L, count++);
 525     push_canvas(L, &cv);
 526     lua_settable(L, -3);
 527     cv = cv->c_lnext;
 528   }
 529
 530   return 1;
 531 }
 532
 533 static int
 534 window_getlines(lua_State *L)
 535 {
 536   struct win *w = check_window(L, 1);
 537   int i;
 538   lua_newtable(L);
 539   for (i = 0; i < fore->w_height; i++)
 540     {
 541       char *p = (char *)w->w_mlines[i].image;
 542       int k, save;
 543       for (k = fore->w_width - 1; k >= 0 && p[k] == ' '; k--)
 544         ;
 545       k +=(p[k] != ' ');
 546       save = p[k];
 547       p[k] = 0;
 548       lua_pushinteger(L, i);
 549       lua_pushstring(L, p);
 550       lua_settable(L, -3);
 551       p[k] = save;
 552     }
 553
 554   return 1;
 555 }
 556
 557 static int
 558 window_gethistory(lua_State *L)
 559 {
 560   struct win *w = check_window(L, 1);
 561   int i;
 562   lua_newtable(L);
 563   for (i = 0; i < fore->w_height; i++)
 564     {
 565       char *p = (char *) w->w_hlines[(w->w_histidx + i) % w->w_histheight].image;
 566       int k, save;
 567       for (k = fore->w_width - 1; k >= 0 && p[k] == ' '; k--)
 568         ;
 569       k +=(p[k] != ' ');
 570       save = p[k];
 571       p[k] = 0;
 572       lua_pushinteger(L, i);
 573       lua_pushstring(L, p);
 574       lua_settable(L, -3);
 575       p[k] = save;
 576     }
 577
 578   return 1;
 579 }
 580
 581 static const luaL_reg window_methods[] = {
 582   {"get_monitor_status", window_get_monitor_status},
 583   {"showing_canvases", window_get_showing_canvases},
 584   {"stuff", window_stuff},
 585   {"activate", window_activate},
 586   {"get_lines", window_getlines},
 587   {"get_history", window_gethistory},
 588   {"hook", LuaRegEvent},
 589   {0, 0}
 590 };
 591
 592 static int
 593 window_tostring(lua_State *L)
 594 {
 595   char str[128];
 596   struct win *w = check_window(L, 1);
 597   snprintf(str, sizeof(str), "{window #%d: '%s'}", w->w_number, w->w_title);
 598   lua_pushstring(L, str);
 599   return 1;
 600 }
 601
 602 static int
 603 window_equality(lua_State *L)
 604 {
 605   struct win *w1 = check_window(L, 1), *w2 = check_window(L, 2);
 606   lua_pushboolean(L, (w1 == w2 || (w1 && w2 && w1->w_number == w2->w_number)));
 607   return 1;
 608 }
 609
 610 static const luaL_reg window_metamethods[] = {
 611   {"__tostring", window_tostring},
 612   {"__eq", window_equality},
 613   {"__gc", screen_object_collect},
 614   {0, 0}
 615 };
 616
 617 static const struct Xet_reg window_setters[] = {
 618   {"title", 0, 0, window_change_title/*absolute setter*/},
 619   {"number", 0, 0, window_change_number/*absolute setter*/},
 620   {0, 0}
 621 };
 622
 623 static const struct Xet_reg window_getters[] = {
 624   {"title", get_string, offsetof(struct win, w_title) + 8},
 625   {"number", get_int, offsetof(struct win, w_number)},
 626   {"dir", get_string, offsetof(struct win, w_dir)},
 627   {"tty", get_string, offsetof(struct win, w_tty)},
 628   {"pid", get_int, offsetof(struct win, w_pid)},
 629   {"group", get_window, offsetof(struct win, w_group)},
 630   {"bell", get_int, offsetof(struct win, w_bell)},
 631   {0, 0}
 632 };
 633
 634
 635 /** }}} */
 636
 637 /** AclUser {{{ */
 638
 639 PUSH_TYPE(user, struct acluser)
 640
 641 CHECK_TYPE(user, struct acluser)
 642
 643 static int
 644 get_user(lua_State *L, void *v)
 645 {
 646   push_user(L, (struct acluser **)v);
 647   return 1;
 648 }
 649
 650 static const luaL_reg user_methods[] = {
 651   {0, 0}
 652 };
 653
 654 static int
 655 user_tostring(lua_State *L)
 656 {
 657   char str[128];
 658   struct acluser *u = check_user(L, 1);
 659   snprintf(str, sizeof(str), "{user '%s'}", u->u_name);
 660   lua_pushstring(L, str);
 661   return 1;
 662 }
 663
 664 static const luaL_reg user_metamethods[] = {
 665   {"__tostring", user_tostring},
 666   {"__gc", screen_object_collect},
 667   {0, 0}
 668 };
 669
 670 static const struct Xet_reg user_setters[] = {
 671   {0, 0}
 672 };
 673
 674 static const struct Xet_reg user_getters[] = {
 675   {"name", get_string, offsetof(struct acluser, u_name)},
 676   {"password", get_string, offsetof(struct acluser, u_password)},
 677   {0, 0}
 678 };
 679
 680 /** }}} */
 681
 682 static int get_display(lua_State *L, void *v);
 683 /** Canvas {{{ */
 684
 685 PUSH_TYPE(canvas, struct canvas)
 686
 687 CHECK_TYPE(canvas, struct canvas)
 688
 689 static int
 690 get_canvas(lua_State *L, void *v)
 691 {
 692   push_canvas(L, (struct canvas **)v);
 693   return 1;
 694 }
 695
 696 static int
 697 canvas_select(lua_State *L)
 698 {
 699   struct canvas *c = check_canvas(L, 1);
 700   if (!display || D_forecv == c)
 701     return 0;
 702   /* FIXME: why do we need this? */
 703   SetCanvasWindow(c, Layer2Window(c->c_layer));
 704
 705   FocusCanvas(c);
 706   return 0;
 707 }
 708
 709 static int
 710 canvas_split(lua_State *L)
 711 {
 712   struct canvas *c = check_canvas(L, 1);
 713   struct canvas *oldfore = D_forecv;
 714   D_forecv = c;
 715   int hori = lua_toboolean(L, 2);
 716   if (hori)
 717     AddCanvas(SLICE_HORI);
 718   else
 719     AddCanvas(SLICE_VERT);
 720   Activate(-1);
 721   D_forecv = oldfore;
 722   return 0;
 723 }
 724
 725 static int
 726 canvas_showwin(lua_State *L)
 727 {
 728   struct canvas *c = check_canvas(L, 1);
 729   if (lua_isnil(L, 2))
 730     SetCanvasWindow(c, 0);
 731   else
 732     {
 733       struct win *w = check_window(L, 2);
 734       SetCanvasWindow(c, w);
 735     }
 736   return 0;
 737 }
 738
 739 static const luaL_reg canvas_methods[] = {
 740   {"select", canvas_select},
 741   {"split", canvas_split},
 742   {"showwin", canvas_showwin},
 743   {0, 0}
 744 };
 745
 746 static const luaL_reg canvas_metamethods[] = {
 747   {"__gc", screen_object_collect},
 748   {0, 0}
 749 };
 750
 751 extern struct mchar mchar_so;
 752 static int
 753 canvas_update_caption(lua_State *L)
 754 {
 755   struct canvas *cv = check_canvas(L, 1);
 756   unsigned int len;
 757   const char *caption = luaL_checklstring(L, 3, &len);
 758   int l, padlen;
 759   padlen = cv->c_xe - cv->c_xs +
 760     (display ? (cv->c_xe + 1 < D_width || D_CLP): 0);
 761   struct win *w = Layer2Window(cv->c_layer);
 762   char * buf = MakeWinMsgEv((char *)caption, w, '%', padlen, &cv->c_captev, 0);
 763   if (cv->c_captev.timeout.tv_sec)
 764     evenq(&cv->c_captev);
 765   l = strlen(buf);
 766
 767   GotoPos(cv->c_xs, cv->c_ye+1);
 768   /*XXX:what does this mean?*/
 769   SetRendition(&mchar_so);
 770   if (l > cv->c_xe - cv->c_xs + 1)
 771     l = cv->c_xe - cv->c_xs + 1;
 772   PutWinMsg(buf, cv->c_xs, l);
 773   l += cv->c_xs;
 774   for (; l <= cv->c_xe; l++)
 775     PUTCHARLP(' ');
 776
 777   return 0;
 778 }
 779
 780 static const struct Xet_reg canvas_setters[] = {
 781   {"caption", 0, 0, canvas_update_caption/*absolute setter*/},
 782   {0, 0}
 783 };
 784
 785 static int
 786 canvas_get_window(lua_State *L)
 787 {
 788   struct canvas *c = check_canvas(L, 1);
 789   struct win *win = Layer2Window(c->c_layer);
 790   if (win)
 791     push_window(L, &win);
 792   else
 793     lua_pushnil(L);
 794   return 1;
 795 }
 796
 797 static const struct Xet_reg canvas_getters[] = {
 798   {"next", get_canvas, offsetof(struct canvas, c_next)},
 799   {"xoff", get_int, offsetof(struct canvas, c_xoff)},
 800   {"yoff", get_int, offsetof(struct canvas, c_yoff)},
 801   {"xs", get_int, offsetof(struct canvas, c_xs)},
 802   {"ys", get_int, offsetof(struct canvas, c_ys)},
 803   {"xe", get_int, offsetof(struct canvas, c_xe)},
 804   {"ye", get_int, offsetof(struct canvas, c_ye)},
 805   {"window", 0, 0, canvas_get_window},
 806   {"display", get_display, offsetof(struct canvas, c_display)},
 807   {0, 0}
 808 };
 809
 810 /** }}} */
 811
 812 /** Layout {{{ */
 813
 814 PUSH_TYPE(layout, struct layout)
 815 CHECK_TYPE(layout, struct layout)
 816
 817 static const struct Xet_reg layout_getters[] = {
 818   {"title", get_string, offsetof(struct layout, lay_title)},
 819   {"number", get_string, offsetof(struct layout, lay_title)},
 820   {"autosave", get_string, offsetof(struct layout, lay_autosave)},
 821   {0,0}
 822 };
 823
 824 int
 825 layout_change_title(lua_State *L)
 826 {
 827   struct layout *lay = check_layout(L, 1);
 828   unsigned int len;
 829   const char *title = luaL_checklstring(L, 3, &len);
 830   free(lay->lay_title);
 831   lay->lay_title= SaveStr(title);
 832   return 0;
 833 }
 834
 835 void LayoutChangeNumber(struct layout *lay, int newnum);
 836
 837 int
 838 layout_change_number(lua_State *L)
 839 {
 840   struct layout *lay = check_layout(L, 1);
 841   int newnum = luaL_checkint(L, 3);
 842   LayoutChangeNumber(lay, newnum);
 843   return 0;
 844 }
 845
 846 static const struct Xet_reg layout_setters[] = {
 847   {"title", 0, 0, layout_change_title/*absolute setter*/},
 848   {"number", 0, 0, layout_change_number/*absolute setter*/},
 849   {"autosave", get_string, offsetof(struct layout, lay_autosave)},
 850   {0, 0}
 851 };
 852
 853 int
 854 layout_select(lua_State *L)
 855 {
 856   struct layout *lay = check_layout(L, 1);
 857   if (!display) return 0;
 858   LoadLayout(lay, &D_canvas);
 859   Activate(0);
 860   return 0;
 861 }
 862
 863 static const luaL_reg layout_methods[] = {
 864   {"select", layout_select},
 865   {0, 0}
 866 };
 867
 868 static const luaL_reg layout_metamethods[] = {
 869   {"__gc", screen_object_collect},
 870   {0, 0}
 871 };
 872
 873 static int
 874 get_layout(lua_State *L, void *v)
 875 {
 876   push_layout(L, (struct layout **)v);
 877   return 1;
 878 }
 879
 880 /** }}} */
 881
 882 /** Display {{{ */
 883
 884 PUSH_TYPE(display, struct display)
 885
 886 CHECK_TYPE(display, struct display)
 887
 888 static int
 889 get_display(lua_State *L, void *v)
 890 {
 891   push_display(L, (struct display **)v);
 892   return 1;
 893 }
 894
 895 static int
 896 display_get_canvases(lua_State *L)
 897 {
 898   struct display *d;
 899   struct canvas *iter;
 900   int count;
 901
 902   d = check_display(L, 1);
 903   lua_newtable(L);
 904   for (iter = d->d_cvlist, count = 0; iter; iter = iter->c_next, count++) {
 905     lua_pushinteger(L, count);
 906     push_canvas(L, &iter);
 907     lua_settable(L, -3);
 908   }
 909
 910   return 1;
 911 }
 912
 913 static int
 914 display_top_canvas(lua_State *L)
 915 {
 916   struct display *d;
 917   d = check_display(L, 1);
 918   push_canvas(L, &d->d_cvlist);
 919
 920   return 1;
 921 }
 922
 923 static int
 924 display_bot_canvas(lua_State *L)
 925 {
 926   struct display *d;
 927   struct canvas *c;
 928   d = check_display(L, 1);
 929
 930   for (c = d->d_cvlist; c->c_next; c = c->c_next)
 931     ;
 932   push_canvas(L, &c);
 933
 934   return 1;
 935 }
 936
 937 static const luaL_reg display_methods[] = {
 938   {"get_canvases", display_get_canvases},
 939   {"top_canvas", display_top_canvas},
 940   {"bottom_canvas", display_bot_canvas},
 941   {0, 0}
 942 };
 943
 944 static int
 945 display_tostring(lua_State *L)
 946 {
 947   char str[128];
 948   struct display *d = check_display(L, 1);
 949   snprintf(str, sizeof(str), "{display: tty = '%s', term = '%s'}", d->d_usertty, d->d_termname);
 950   lua_pushstring(L, str);
 951   return 1;
 952 }
 953
 954 static const luaL_reg display_metamethods[] = {
 955   {"__tostring", display_tostring},
 956   {"__gc", screen_object_collect},
 957   {0, 0}
 958 };
 959
 960 static int
 961 display_new_idle_timeout(lua_State *L)
 962 {
 963   struct display *disp = check_display(L, 1);
 964   int timeout = luaL_checkinteger(L, 3) * 1000;
 965   struct event *ev = &disp->d_idleev;
 966   if (timeout > 0)
 967     {
 968       SetTimeout(ev, timeout);
 969       if (!ev->queued)
 970         evenq(ev);
 971     }
 972   else
 973     evdeq(ev);
 974
 975   return 0;
 976 }
 977
 978 static const struct Xet_reg display_setters[] = {
 979   {"idle_timeout", 0, 0, display_new_idle_timeout/*absolute setter*/},
 980   {0, 0}
 981 };
 982
 983 static const struct Xet_reg display_getters[] = {
 984   {"tty", get_string, offsetof(struct display, d_usertty)},
 985   {"term", get_string, offsetof(struct display, d_termname)},
 986   {"fore", get_window, offsetof(struct display, d_fore)},
 987   {"other", get_window, offsetof(struct display, d_other)},
 988   {"width", get_int, offsetof(struct display, d_width)},
 989   {"height", get_int, offsetof(struct display, d_height)},
 990   {"user", get_user, offsetof(struct display, d_user)},
 991   {"layout", get_layout, offsetof(struct display, d_layout)},
 992   {0, 0}
 993 };
 994
 995 /** }}} */
 996
 997 /** Screen {{{ */
 998
 999 static int
1000 screen_get_windows(lua_State *L)
1001 {
1002   struct win *iter;
1003   int count;
1004
1005   lua_newtable(L);
1006   for (iter = windows, count = 0; iter; iter = iter->w_next, count++) {
1007     lua_pushinteger(L, iter->w_number);
1008     push_window(L, &iter);
1009     lua_settable(L, -3);
1010   }
1011
1012   return 1;
1013 }
1014
1015 static int
1016 screen_get_displays(lua_State *L)
1017 {
1018   struct display *iter;
1019   int count;
1020
1021   lua_newtable(L);
1022   for (iter = displays, count = 0; iter; iter = iter->d_next, count++) {
1023     lua_pushinteger(L, count);
1024     push_display(L, &iter);
1025     lua_settable(L, -3);
1026   }
1027
1028   return 1;
1029 }
1030
1031 extern struct layout *layouts;
1032 static int
1033 screen_get_layouts(lua_State *L)
1034 {
1035   struct layout *iter;
1036   int count;
1037
1038   lua_newtable(L);
1039   for (iter = layouts, count = 0; iter; iter = iter->lay_next, count++) {
1040     lua_pushinteger(L, iter->lay_number);
1041     push_layout(L, &iter);
1042     lua_settable(L, -3);
1043   }
1044
1045   return 1;
1046 }
1047
1048 static int
1049 screen_get_display(lua_State *L)
1050 {
1051   push_display(L, &display);
1052   return 1;
1053 }
1054
1055 static int
1056 screen_exec_command(lua_State *L)
1057 {
1058   const char *command;
1059   unsigned int len;
1060
1061   command = luaL_checklstring(L, 1, &len);
1062   if (command)
1063     RcLine((char *)command, len);
1064
1065   return 0;
1066 }
1067
1068 static int
1069 screen_append_msg(lua_State *L)
1070 {
1071   const char *msg, *color;
1072   unsigned int len;
1073   msg = luaL_checklstring(L, 1, &len);
1074   if (lua_isnil(L, 2))
1075     color = NULL;
1076   else
1077     color = luaL_checklstring(L, 2, &len);
1078   AppendWinMsgRend(msg, color);
1079   return 0;
1080 }
1081
1082 void
1083 script_input_fn(char *buf, int len, char *priv)
1084 {
1085   lua_handler lh = (lua_handler)priv;
1086   struct sfile *sf = (struct sfile *)lh->L;
1087   lua_State *L = sf->L;
1088   if (!L) {
1089       free(sf);
1090       LuaFreeHandler(L, &lh);
1091       return;
1092   }
1093
1094   lh->L = L;
1095   LuaPushHandler(lh);
1096   lua_pushstring(L, buf);
1097   if (lua_pcall(L, 1, 0, 0) == LUA_ERRRUN)
1098     {
1099       if(lua_isstring(L, -1))
1100         {
1101           LuaShowErr(L);
1102         }
1103     }
1104   sf->inuse = 0;
1105   LuaFreeHandler(L, &lh);
1106 }
1107
1108 static int
1109 screen_input(lua_State *L)
1110 {
1111   char *ss;
1112   int n;
1113   const char * prompt = NULL, *prefill = NULL;
1114   lua_handler lh;
1115   struct sfile *sf = LuaGetSFile(L);
1116
1117   prompt = luaL_checkstring(L, 1);
1118   lh = LuaCheckHandler(L, 2, 1);
1119   /* Hack! This is used to prevent from accessing unloaded script.*/
1120   lh->L = (lua_State *)sf;
1121   if (!lh)
1122     luaL_error(L, "Out of Memory");
1123
1124   if (lua_gettop(L) >= 3)
1125     prefill = luaL_checkstring(L, 3);
1126
1127
1128   sf->inuse = 1;
1129   Input((char *)prompt, 100, INP_COOKED, script_input_fn, (char *)lh, 0);
1130
1131   if (!prefill)
1132     return 0;
1133   for (; *prefill; prefill++)
1134     {
1135       if ((*(unsigned char *)prefill & 0x7f) < 0x20 || *prefill == 0x7f)
1136         continue;
1137       ss = (char *)prefill;
1138       n = 1;
1139       LayProcess(&ss, &n);
1140     }
1141   return 0;
1142 }
1143
1144 static void
1145 sev_schedule_fn(struct event *ev, char *data)
1146 {
1147   lua_handler lh = (lua_handler)data;
1148   struct sfile *sf = (struct sfile *)lh->L;
1149   lua_State *L = sf->L;
1150   if (!L) {
1151       free(sf);
1152       LuaFreeHandler(L, &lh);
1153       return;
1154   }
1155
1156   evdeq(ev);
1157   Free(ev);
1158
1159   lh->L = L;
1160   LuaPushHandler(lh);
1161   if (lua_pcall(L, 1, 0, 0) == LUA_ERRRUN)
1162     {
1163       if(lua_isstring(L, -1))
1164         {
1165           LuaShowErr(L);
1166         }
1167     }
1168   sf->inuse = 0;
1169   LuaFreeHandler(L, &lh);
1170 }
1171
1172 static int
1173 screen_schedule(lua_State *L)
1174 {
1175   int timeout = luaL_checkinteger(L, 1);
1176   lua_handler lh;
1177   struct sfile *sf = LuaGetSFile(L);
1178   struct event *ev;
1179   if (timeout <= 0)
1180     return 0;
1181   lh = LuaCheckHandler(L, 2, 1);
1182   lh->L = (lua_State *)sf;
1183
1184   ev = (struct event *) calloc(1, sizeof(struct event));
1185   if (!ev)
1186     {
1187       LuaFreeHandler(L, &lh);
1188       luaL_error(L, "Out of Memory");
1189     }
1190
1191   ev->type = EV_TIMEOUT;
1192   ev->data = (char *)lh;
1193   ev->handler = sev_schedule_fn;
1194   evenq(ev);
1195   SetTimeout(ev, timeout * 1000);
1196   sf->inuse = 1;
1197   return 0;
1198 }
1199
1200 static const luaL_reg screen_methods[] = {
1201   {"windows", screen_get_windows},
1202   {"displays", screen_get_displays},
1203   {"layouts", screen_get_layouts},
1204   {"display", screen_get_display},
1205   {"command", screen_exec_command},
1206   {"append_msg", screen_append_msg},
1207   {"hook", LuaRegEvent},
1208   {"input", screen_input},
1209   {"schedule", screen_schedule},
1210   {0, 0}
1211 };
1212
1213 static const luaL_reg screen_metamethods[] = {
1214   {0, 0}
1215 };
1216
1217 static const struct Xet_reg screen_setters[] = {
1218   {0, 0}
1219 };
1220
1221 static const struct Xet_reg screen_getters[] = {
1222   {0, 0}
1223 };
1224
1225 /** }}} */
1226
1227 /** Public functions {{{ */
1228
1229 /* FIXME: This code only tracks one unhook ticket for a lua func.
1230  * So it does not work if one func is registered more than one times. */
1231 static void
1232 prepare_weak_table(lua_State *L, const char *name, const char *mode)
1233 {
1234   luaL_getmetatable(L, "screen");
1235
1236   lua_pushstring(L, name);
1237   lua_newtable(L);
1238
1239   /* prepare a metatable to indicate weak table */
1240   lua_newtable(L);
1241   lua_pushstring(L, "__mode");
1242   lua_pushstring(L, mode);
1243   lua_rawset(L, -3);
1244   /* Mark weak table */
1245   lua_setmetatable(L, -2);
1246   lua_rawset(L, -3);
1247   lua_pop(L, 1);
1248 }
1249
1250 int LuaInit(void)
1251 {
1252   return 0;
1253 }
1254 lua_State *
1255 LuaNewState(struct sfile *slist)
1256 {
1257   lua_State *L = luaL_newstate();
1258
1259   luaL_openlibs(L);
1260
1261 #define REGISTER(X) struct_register(L, #X , X ## _methods, X##_metamethods, X##_setters, X##_getters)
1262
1263   REGISTER(screen);
1264   REGISTER(window);
1265   REGISTER(display);
1266   REGISTER(user);
1267   REGISTER(canvas);
1268   REGISTER(callback);
1269
1270   /* To store handler funcs */
1271
1272   /*
1273    * funcreg[key]->func
1274    * */
1275   prepare_weak_table(L, "_funcreg", " ");
1276
1277   /* Hold a reference to the sfile structure to ease unloading the script.*/
1278   luaL_getmetatable(L, "screen");
1279   lua_pushstring(L, "_sfile");
1280   lua_pushlightuserdata(L, slist);
1281   lua_rawset(L, -3);
1282   lua_pop(L, 1);
1283   slist->L = L;
1284   slist->inuse = 0;
1285   return L;
1286 }
1287
1288 /* An error message on top of the stack. */
1289 static void
1290 LuaShowErr(lua_State *L)
1291 {
1292   struct display *d = display;
1293   unsigned int len;
1294   const char *message = luaL_checklstring(L, -1, &len);
1295   lua_pop(L, 1);
1296   LMsg(0, "%s", message ? message : "Unknown error");
1297   display = d;
1298 }
1299
1300 void
1301 LuaUnload(struct sfile *slist)
1302 {
1303   struct sfile **plist = &scripts;
1304   lua_close(slist->L);
1305   while (*plist) {
1306       if (*plist == slist) {
1307           *plist = slist->next;
1308           break;
1309       }
1310       plist = &(*plist)->next;
1311   }
1312
1313   //Delay reclaiming the structure if it's still in use.
1314   if (!slist->inuse)
1315     free(slist);
1316   else
1317     slist->L = NULL;
1318 }
1319
1320 /* FIXME: Think about this: will it affect the registered handlers?*/
1321 int LuaSource(const char *file, int async)
1322 {
1323   struct stat st;
1324   if (stat(file, &st) == -1)
1325     Msg(errno, "Error loading lua script file '%s'", file);
1326   else
1327     {
1328       int len = strlen(file);
1329       ino_t inode = st.st_ino;
1330       struct sfile *slist = scripts;
1331
1332       if (len < 4 || strncmp(file + len - 4, ".lua", 4) != 0)
1333         return 0;
1334
1335       while (slist) {
1336           if (slist->inode == inode)
1337             break;
1338           slist = slist->next;
1339       }
1340       if (slist)
1341         LuaUnload(slist);
1342
1343       slist = (struct sfile *) malloc(sizeof(struct sfile));
1344       slist->next = scripts;
1345       LuaNewState(slist);
1346       slist->inode = inode;
1347
1348       if (luaL_dofile(slist->L, file) && lua_isstring(slist->L, -1))
1349         {
1350           LuaShowErr(slist->L);
1351           lua_close(slist->L);
1352           free(slist);
1353           return 0;
1354         }
1355       scripts = slist;
1356       return 1;
1357     }
1358   return 0;
1359 }
1360
1361 int LuaFinit(void)
1362 {
1363   struct sfile *slist = scripts;
1364   while (slist) {
1365       struct sfile *tmp = slist;
1366       lua_close(slist->L);
1367       slist = slist->next;
1368       free(tmp);
1369   }
1370   scripts = 0;
1371   return 0;
1372 }
1373
1374 static void
1375 push_stringarray(lua_State *L, char **args)
1376 {
1377   int i;
1378   lua_newtable(L);
1379   for (i = 1; args && *args; i++) {
1380     lua_pushinteger(L, i);
1381     lua_pushstring(L, *args++);
1382     lua_settable(L, -3);
1383   }
1384 }
1385
1386 int
1387 LuaPushParams(lua_State *L, const char *params, va_list va)
1388 {
1389   int num = 0;
1390   while (*params)
1391     {
1392       switch (*params)
1393         {
1394         case 's':
1395           lua_pushstring(L, va_arg(va, char *));
1396           break;
1397         case 'S':
1398           push_stringarray(L, va_arg(va, char **));
1399           break;
1400         case 'i':
1401           lua_pushinteger(L, va_arg(va, int));
1402           break;
1403         case 'd':
1404           {
1405             struct display *d = va_arg(va, struct display *);
1406             push_display(L, &d);
1407             break;
1408           }
1409         case 'w':
1410           {
1411             struct win *w = va_arg(va, struct win *);
1412             push_window(L, &w);
1413             break;
1414           }
1415         case 'c':
1416           {
1417             struct canvas *c = va_arg(va, struct canvas *);
1418             push_canvas(L, &c);
1419             break;
1420           }
1421         }
1422       params++;
1423       num++;
1424     }
1425   return num;
1426 }
1427
1428 int LuaCall(const char *func, const char **argv)
1429 {
1430   int argc;
1431   struct sfile *slist = scripts;
1432   lua_State *L = NULL;
1433   while (slist) {
1434       L = slist->L;
1435       lua_getfield(L, LUA_GLOBALSINDEX, func);
1436       if (lua_isnil(L, -1))
1437         {
1438           lua_pop(L, 1);
1439           slist = slist->next;
1440           return 0;
1441         }
1442       else
1443         break;
1444   }
1445
1446   if (!slist) {
1447       if (L) {
1448           lua_pushstring(L, "Could not find the script function\n");
1449           LuaShowErr(L);
1450       }
1451       return 0;
1452   }
1453   StackDump(L, "Before LuaCall\n");
1454
1455   for (argc = 0; *argv; argv++, argc++)
1456     {
1457       lua_pushstring(L, *argv);
1458     }
1459   if (lua_pcall(L, argc, 0, 0) == LUA_ERRRUN)
1460     {
1461       if(lua_isstring(L, -1))
1462         {
1463           StackDump(L, "After LuaCall\n");
1464           LuaShowErr(L);
1465           return 0;
1466         }
1467     }
1468   return 1;
1469 }
1470
1471 /*** Lua callback handler management {{{ */
1472
1473 int
1474 LuaPushHTable(lua_State *L, int screen, const char * t)
1475 {
1476   lua_pushstring(L, t);
1477   lua_rawget(L, screen);
1478   /* FIXME: Do we need to balance the stack here? */
1479   if (lua_isnil(L, -1))
1480     luaL_error(L, "Fatal! Fail to get function registeration table!");
1481   return lua_gettop(L);
1482 }
1483
1484 void
1485 LuaPushHandler(lua_handler lh)
1486 {
1487   int funcreg;
1488   lua_State *L = lh->L;
1489   if (lh->type == LUA_HANDLER_TYPE_F)
1490     {
1491       luaL_getmetatable(L, "screen");
1492       funcreg = LuaPushHTable(L, lua_gettop(L), "_funcreg");
1493       lua_rawgeti(L, funcreg, lh->u.reference);
1494       lua_replace(L, -3);
1495       lua_pop(L, 1);
1496     }
1497   else
1498     {
1499       lua_getfield(L, LUA_GLOBALSINDEX, lh->u.name);
1500     }
1501 }
1502
1503 int
1504 LuaFuncKey(lua_State *L, int idx, int ref)
1505 {
1506   int key, funcreg, sc;
1507   luaL_getmetatable(L, "screen");
1508   sc = lua_gettop(L);
1509   funcreg = LuaPushHTable(L, sc, "_funcreg");
1510
1511   lua_pushvalue(L, idx);
1512   key = luaL_ref(L, funcreg);
1513   lua_pop(L, 2);
1514   return key;
1515 }
1516
1517 void
1518 LuaHUnRef(lua_State *L, int key)
1519 {
1520   int funcreg, sc;
1521   luaL_getmetatable(L, "screen");
1522   sc = lua_gettop(L);
1523   funcreg = LuaPushHTable(L, sc, "_funcreg");
1524   luaL_unref(L, funcreg, key);
1525 }
1526
1527 lua_handler
1528 LuaCheckHandler(lua_State *L, int idx, int ref)
1529 {
1530   int key;
1531   if (idx < 0)
1532     idx = lua_gettop(L) + 1 - idx;
1533
1534   if (lua_isstring(L, idx))
1535     {
1536       const char * handler;
1537       /* registered with func name.*/
1538       handler = luaL_checkstring(L, idx);
1539       lua_getfield(L, LUA_GLOBALSINDEX, handler);
1540       if (!lua_isfunction(L, -1))
1541         luaL_error(L, "The specified handler %s in param #%d is not a function", handler, idx);
1542       lua_pop(L, 1);
1543       return LuaAllocHandler(L, handler, 0);
1544     }
1545   else if (!lua_isfunction(L, idx))
1546     luaL_error(L, "Handler should be a function or the name of function");
1547
1548   key = LuaFuncKey(L, idx, ref);
1549   return LuaAllocHandler(L, NULL, key);
1550 }
1551
1552 /* }}} **/
1553
1554 static int
1555 LuaDispatch(void *handler, const char *params, va_list va)
1556 {
1557   lua_handler lh = (lua_handler)handler;
1558   int argc, retvalue;
1559   lua_State *L = lh->L;
1560
1561   StackDump(L, "before dispatch");
1562
1563   LuaPushHandler(lh);
1564   if (lua_isnil(L, -1))
1565     {
1566       lua_pop(L, 1);
1567       return 0;
1568     }
1569   argc = LuaPushParams(L, params, va);
1570
1571   if (lua_pcall(L, argc, 1, 0) == LUA_ERRRUN && lua_isstring(L, -1))
1572     {
1573       StackDump(L, "After LuaDispatch\n");
1574       LuaShowErr(L);
1575       return 0;
1576     }
1577   retvalue = lua_tonumber(L, -1);
1578   lua_pop(L, 1);
1579   return retvalue;
1580 }
1581
1582 #define SEVNAME_MAX 30
1583 static int
1584 LuaRegEvent(lua_State *L)
1585 {
1586   /* signature: hook(obj, event, handler, priv);
1587    *        or: hook(event, handler, priv)
1588    *   returns: A ticket for later unregister. */
1589   int idx = 1, argc = lua_gettop(L);
1590   unsigned int priv = 31; /* Default privilege */
1591   lua_handler lh;
1592
1593   char *obj = NULL;
1594   const char *objname = "global";
1595
1596   static char evbuf[SEVNAME_MAX];
1597   const char *event;
1598
1599   struct script_event *sev;
1600
1601   StackDump(L, "Before RegEvent\n");
1602
1603   /* Identify the object, if specified */
1604   if (luaL_getmetafield(L, 1, "_objname"))
1605     {
1606       objname = luaL_checkstring(L, -1);
1607       lua_pop(L, 1);
1608       if (!strcmp("screen", objname))
1609         objname = "global";
1610       else
1611         {
1612           obj = get_broker_obj((struct broker **)lua_touserdata(L, 1));
1613           if (!obj)
1614             return luaL_error(L, "Invalid object specified");
1615         }
1616       idx++;
1617     }
1618
1619   event = luaL_checkstring(L, idx++);
1620   snprintf(evbuf, SEVNAME_MAX, "%s_%s", objname, event);
1621
1622   /* Check and get the handler */
1623   lh = LuaCheckHandler(L, idx++, 1);
1624   if (!lh)
1625     luaL_error(L, "Out of memory");
1626
1627   StackDump(L, "In RegEvent\n");
1628
1629   if (idx <= argc)
1630     priv = luaL_checkinteger(L, idx);
1631
1632   sev = object_get_event(obj, evbuf);
1633   if (sev)
1634     {
1635       struct listener *l;
1636       l = (struct listener *)malloc(sizeof(struct listener));
1637       if (!l)
1638         return luaL_error(L, "Out of memory");
1639       l->priv = priv;
1640       l->bd = &lua_binding;
1641       l->handler = (void *)lh;
1642       register_listener(sev, l);
1643       /* Return the ticket for un-register */
1644       push_callback(L, &l);
1645     }
1646   else
1647     return luaL_error(L, "Invalid event specified: %s for object %s", event, objname);
1648
1649   StackDump(L, "After RegEvent\n");
1650   return 1;
1651 }
1652
1653 /** }}} */
1654
1655 struct binding lua_binding =
1656 {
1657     "lua", /*name*/
1658     0,     /*inited*/
1659     0,     /*registered*/
1660     LuaInit,
1661     LuaFinit,
1662     LuaCall,
1663     LuaSource,
1664     LuaDispatch,
1665     0,     /*b_next*/
1666 };
1667