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