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
  82 static int LuaDispatch(void *handler, const char *params, va_list va);
  83 static int LuaRegEvent(lua_State *L);
  84 static void LuaShowErr(lua_State *L);
  85 struct binding lua_binding;
  86
  87 enum
  88 {
  89   LUA_HANDLER_TYPE_N = 1,
  90   LUA_HANDLER_TYPE_F
  91 };
  92
  93 struct lua_handler
  94 {
  95   int type;
  96   union
  97   {
  98     const char *name;
  99     int reference;
 100   } u;
 101 };
 102
 103 typedef struct lua_handler *lua_handler;
 104 void LuaPushHandler(lua_State *L, lua_handler lh);
 105 void LuaHUnRef(lua_State *L, int key);
 106 lua_handler LuaCheckHandler(lua_State *L, int idx, int ref);
 107
 108 lua_handler
 109 LuaAllocHandler(const char *name, int ref)
 110 {
 111   struct lua_handler *lh;
 112   lh = (struct lua_handler*) malloc(sizeof(struct lua_handler));
 113   if (!lh)
 114     return NULL;
 115
 116   if (name)
 117     {
 118       lh->type = LUA_HANDLER_TYPE_N;
 119       lh->u.name = SaveStr(name);
 120     }
 121   else
 122     {
 123       lh->type = LUA_HANDLER_TYPE_F;
 124       lh->u.reference = ref;
 125     }
 126
 127   return lh;
 128 }
 129
 130 void
 131 LuaFreeHandler(lua_State *L, struct lua_handler **lh)
 132 {
 133   if ((*lh)->type == LUA_HANDLER_TYPE_N)
 134     Free((*lh)->u.name)
 135   else
 136     {
 137       LuaHUnRef(L, (*lh)->u.reference);
 138       (*lh)->u.reference = 0;
 139     }
 140   Free(*lh);
 141 }
 142 /** Template {{{ */
 143
 144 #define CHECK_TYPE(name, type) \
 145 static type * \
 146 check_##name(lua_State *L, int index) \
 147 { \
 148   type **var; \
 149   luaL_checktype(L, index, LUA_TUSERDATA); \
 150   var = (type **) luaL_checkudata(L, index, #name); \
 151   if (!var || !*var) \
 152     luaL_typerror(L, index, #name); \
 153   return *var; \
 154 }
 155
 156 #define PUSH_TYPE(name, type) \
 157 static void \
 158 push_##name(lua_State *L, type **t) \
 159 { \
 160   if (!t || !*t) \
 161     lua_pushnil(L); \
 162   else \
 163     { \
 164       type **r; \
 165       r = (type **)lua_newuserdata(L, sizeof(type *)); \
 166       *r = *t; \
 167       luaL_getmetatable(L, #name); \
 168       lua_setmetatable(L,-2); \
 169     } \
 170 }
 171
 172 /* Much of the following template comes from:
 173  *      http://lua-users.org/wiki/BindingWithMembersAndMethods
 174  */
 175
 176 static int get_int (lua_State *L, void *v)
 177 {
 178   lua_pushinteger (L, *(int*)v);
 179   return 1;
 180 }
 181
 182 static int set_int (lua_State *L, void *v)
 183 {
 184   *(int*)v = luaL_checkint(L, 3);
 185   return 0;
 186 }
 187
 188 static int get_number (lua_State *L, void *v)
 189 {
 190   lua_pushnumber(L, *(lua_Number*)v);
 191   return 1;
 192 }
 193
 194 static int set_number (lua_State *L, void *v)
 195 {
 196   *(lua_Number*)v = luaL_checknumber(L, 3);
 197   return 0;
 198 }
 199
 200 static int get_string (lua_State *L, void *v)
 201 {
 202   lua_pushstring(L, (char*)v );
 203   return 1;
 204 }
 205
 206 static int set_string (lua_State *L, void *v)
 207 {
 208   *(const char**)v = luaL_checkstring(L, 3);
 209   return 0;
 210 }
 211
 212 typedef int (*Xet_func) (lua_State *L, void *v);
 213
 214 /* member info for get and set handlers */
 215 struct Xet_reg
 216 {
 217   const char *name;  /* member name */
 218   Xet_func func;     /* get or set function for type of member */
 219   size_t offset;     /* offset of member within the struct */
 220   int (*absolute)(lua_State *);
 221 };
 222
 223 static void Xet_add (lua_State *L, const struct Xet_reg *l)
 224 {
 225   if (!l)
 226     return;
 227   for (; l->name; l++)
 228     {
 229       lua_pushstring(L, l->name);
 230       lua_pushlightuserdata(L, (void*)l);
 231       lua_settable(L, -3);
 232     }
 233 }
 234
 235 static int Xet_call (lua_State *L)
 236 {
 237   /* for get: stack has userdata, index, lightuserdata */
 238   /* for set: stack has userdata, index, value, lightuserdata */
 239   const struct Xet_reg *m = (const struct Xet_reg *)lua_touserdata(L, -1);  /* member info */
 240   lua_pop(L, 1);                               /* drop lightuserdata */
 241   luaL_checktype(L, 1, LUA_TUSERDATA);
 242   if (m->absolute)
 243     return m->absolute(L);
 244   return m->func(L, *(char**)lua_touserdata(L, 1) + m->offset);
 245 }
 246
 247 static int index_handler (lua_State *L)
 248 {
 249   /* stack has userdata, index */
 250   lua_pushvalue(L, 2);                     /* dup index */
 251   lua_rawget(L, lua_upvalueindex(1));      /* lookup member by name */
 252   if (!lua_islightuserdata(L, -1))
 253     {
 254       lua_pop(L, 1);                         /* drop value */
 255       lua_pushvalue(L, 2);                   /* dup index */
 256       lua_gettable(L, lua_upvalueindex(2));  /* else try methods */
 257       if (lua_isnil(L, -1))                  /* invalid member */
 258         luaL_error(L, "cannot get member '%s'", lua_tostring(L, 2));
 259       return 1;
 260     }
 261   return Xet_call(L);                      /* call get function */
 262 }
 263
 264 static int newindex_handler (lua_State *L)
 265 {
 266   /* stack has userdata, index, value */
 267   lua_pushvalue(L, 2);                     /* dup index */
 268   lua_rawget(L, lua_upvalueindex(1));      /* lookup member by name */
 269   if (!lua_islightuserdata(L, -1))         /* invalid member */
 270     luaL_error(L, "cannot set member '%s'", lua_tostring(L, 2));
 271   return Xet_call(L);                      /* call set function */
 272 }
 273
 274 static int
 275 struct_register(lua_State *L, const char *name, const luaL_reg fn_methods[], const luaL_reg meta_methods[],
 276     const struct Xet_reg setters[], const struct Xet_reg getters[])
 277 {
 278   int metatable, methods;
 279
 280   /* create methods table & add it to the table of globals */
 281   luaL_register(L, name, fn_methods);
 282   methods = lua_gettop(L);
 283
 284   /* create metatable & add it to the registry */
 285   luaL_newmetatable(L, name);
 286   luaL_register(L, 0, meta_methods);  /* fill metatable */
 287
 288   /* To identify the type of object */
 289   lua_pushstring(L, "_objname");
 290   lua_pushstring(L, name);
 291   lua_rawset(L, -3);
 292
 293   metatable = lua_gettop(L);
 294
 295   lua_pushliteral(L, "__metatable");
 296   lua_pushvalue(L, methods);    /* dup methods table*/
 297   lua_rawset(L, metatable);     /* hide metatable:
 298                                    metatable.__metatable = methods */
 299
 300   lua_pushliteral(L, "__index");
 301   lua_pushvalue(L, metatable);  /* upvalue index 1 */
 302   Xet_add(L, getters);     /* fill metatable with getters */
 303   lua_pushvalue(L, methods);    /* upvalue index 2 */
 304   lua_pushcclosure(L, index_handler, 2);
 305   lua_rawset(L, metatable);     /* metatable.__index = index_handler */
 306
 307   lua_pushliteral(L, "__newindex");
 308   lua_newtable(L);              /* table for members you can set */
 309   Xet_add(L, setters);     /* fill with setters */
 310   lua_pushcclosure(L, newindex_handler, 1);
 311   lua_rawset(L, metatable);     /* metatable.__newindex = newindex_handler */
 312
 313   /* FIXME: Why do we leave an element on the stack? */
 314   lua_pop(L, 1);                /* drop metatable */
 315   return 1;                     /* return methods on the stack */
 316 }
 317
 318 /** }}} */
 319
 320 /** Callback {{{ */
 321 PUSH_TYPE(callback, struct listener)
 322
 323 static int
 324 callback_unhook(lua_State *L)
 325 {
 326   /*Emulate check_callback() */
 327   struct listener **ppl;
 328   luaL_checktype(L, 1, LUA_TUSERDATA);
 329   ppl = (struct listener **) luaL_checkudata(L, 1, "callback");
 330
 331   if (!ppl)
 332     luaL_typerror(L, 1, "callback");
 333
 334   if (!*ppl)
 335     {
 336       lua_pushboolean(L, 0);
 337       lua_pushstring(L, "Callback already unhooked.");
 338       LuaShowErr(L);
 339     }
 340   else
 341     {
 342       LuaFreeHandler(L, (lua_handler *)&(*ppl)->handler);
 343       unregister_listener(*ppl);
 344       *ppl = 0;
 345       lua_pushboolean(L, 1);
 346     }
 347   return 1;
 348 }
 349
 350 static const luaL_reg callback_methods[] = {
 351   {"unhook", callback_unhook},
 352   {0, 0}
 353 };
 354
 355 static const luaL_reg callback_metamethods[] = {
 356   {0, 0}
 357 };
 358
 359 static const struct Xet_reg callback_setters[] = {
 360   {0, 0}
 361 };
 362
 363 static const struct Xet_reg callback_getters[] = {
 364   {0, 0}
 365 };
 366
 367
 368 /** }}} */
 369
 370 /** Window {{{ */
 371
 372 PUSH_TYPE(window, struct win)
 373
 374 CHECK_TYPE(window, struct win)
 375
 376 static int get_window(lua_State *L, void *v)
 377 {
 378   push_window(L, (struct win **)v);
 379   return 1;
 380 }
 381
 382 static int
 383 window_change_title(lua_State *L)
 384 {
 385   struct win *w = check_window(L, 1);
 386   unsigned int len;
 387   const char *title = luaL_checklstring(L, 2, &len);
 388   ChangeAKA(w, (char *)title, len);
 389   return 0;
 390 }
 391
 392 static int
 393 window_get_monitor_status(lua_State *L)
 394 {
 395   struct win *w = check_window(L, 1);
 396   int activity = luaL_checkint(L, 2);
 397   if (activity)
 398     /*monitor*/
 399     lua_pushinteger(L, w->w_monitor != MON_OFF);
 400   else
 401     /*silence*/
 402     lua_pushinteger(L, w->w_silence == SILENCE_ON ? w->w_silencewait: 0);
 403
 404   return 1;
 405 }
 406
 407 static const luaL_reg window_methods[] = {
 408   {"get_monitor_status", window_get_monitor_status},
 409   {"hook", LuaRegEvent},
 410   {0, 0}
 411 };
 412
 413 static int
 414 window_tostring(lua_State *L)
 415 {
 416   char str[128];
 417   struct win *w = check_window(L, 1);
 418   snprintf(str, sizeof(str), "{window #%d: '%s'}", w->w_number, w->w_title);
 419   lua_pushstring(L, str);
 420   return 1;
 421 }
 422
 423 static int
 424 window_equality(lua_State *L)
 425 {
 426   struct win *w1 = check_window(L, 1), *w2 = check_window(L, 2);
 427   lua_pushboolean(L, (w1 == w2 || (w1 && w2 && w1->w_number == w2->w_number)));
 428   return 1;
 429 }
 430
 431 static const luaL_reg window_metamethods[] = {
 432   {"__tostring", window_tostring},
 433   {"__eq", window_equality},
 434   {0, 0}
 435 };
 436
 437 static const struct Xet_reg window_setters[] = {
 438   {"title", 0, 0, window_change_title/*absolute setter*/},
 439   {0, 0}
 440 };
 441
 442 static const struct Xet_reg window_getters[] = {
 443   {"title", get_string, offsetof(struct win, w_title) + 8},
 444   {"number", get_int, offsetof(struct win, w_number)},
 445   {"dir", get_string, offsetof(struct win, w_dir)},
 446   {"tty", get_string, offsetof(struct win, w_tty)},
 447   {"pid", get_int, offsetof(struct win, w_pid)},
 448   {"group", get_window, offsetof(struct win, w_group)},
 449   {"bell", get_int, offsetof(struct win, w_bell)},
 450   {0, 0}
 451 };
 452
 453
 454 /** }}} */
 455
 456 /** AclUser {{{ */
 457
 458 PUSH_TYPE(user, struct acluser)
 459
 460 CHECK_TYPE(user, struct acluser)
 461
 462 static int
 463 get_user(lua_State *L, void *v)
 464 {
 465   push_user(L, (struct acluser **)v);
 466   return 1;
 467 }
 468
 469 static const luaL_reg user_methods[] = {
 470   {0, 0}
 471 };
 472
 473 static int
 474 user_tostring(lua_State *L)
 475 {
 476   char str[128];
 477   struct acluser *u = check_user(L, 1);
 478   snprintf(str, sizeof(str), "{user '%s'}", u->u_name);
 479   lua_pushstring(L, str);
 480   return 1;
 481 }
 482
 483 static const luaL_reg user_metamethods[] = {
 484   {"__tostring", user_tostring},
 485   {0, 0}
 486 };
 487
 488 static const struct Xet_reg user_setters[] = {
 489   {0, 0}
 490 };
 491
 492 static const struct Xet_reg user_getters[] = {
 493   {"name", get_string, offsetof(struct acluser, u_name)},
 494   {"password", get_string, offsetof(struct acluser, u_password)},
 495   {0, 0}
 496 };
 497
 498 /** }}} */
 499
 500 /** Canvas {{{ */
 501
 502 PUSH_TYPE(canvas, struct canvas)
 503
 504 CHECK_TYPE(canvas, struct canvas)
 505
 506 static int
 507 get_canvas(lua_State *L, void *v)
 508 {
 509   push_canvas(L, (struct canvas **)v);
 510   return 1;
 511 }
 512
 513 static int
 514 canvas_select(lua_State *L)
 515 {
 516   struct canvas *c = check_canvas(L, 1);
 517   if (!display || D_forecv == c)
 518     return 0;
 519   SetCanvasWindow(c, Layer2Window(c->c_layer));
 520   D_forecv = c;
 521
 522   /* XXX: the following all is duplicated from process.c:DoAction.
 523    * Should these be in some better place?
 524    */
 525   ResizeCanvas(&D_canvas);
 526   RecreateCanvasChain();
 527   RethinkDisplayViewports();
 528   ResizeLayersToCanvases();     /* redisplays */
 529   fore = D_fore = Layer2Window(D_forecv->c_layer);
 530   flayer = D_forecv->c_layer;
 531 #ifdef RXVT_OSC
 532   if (D_xtermosc[2] || D_xtermosc[3])
 533     {
 534       Activate(-1);
 535       break;
 536     }
 537 #endif
 538   RefreshHStatus();
 539 #ifdef RXVT_OSC
 540   RefreshXtermOSC();
 541 #endif
 542   flayer = D_forecv->c_layer;
 543   CV_CALL(D_forecv, LayRestore();LaySetCursor());
 544   WindowChanged(0, 'F');
 545   return 1;
 546 }
 547
 548 static const luaL_reg canvas_methods[] = {
 549   {"select", canvas_select},
 550   {0, 0}
 551 };
 552
 553 static const luaL_reg canvas_metamethods[] = {
 554   {0, 0}
 555 };
 556
 557 static const struct Xet_reg canvas_setters[] = {
 558   {0, 0}
 559 };
 560
 561 static int
 562 canvas_get_window(lua_State *L)
 563 {
 564   struct canvas *c = check_canvas(L, 1);
 565   struct win *win = Layer2Window(c->c_layer);
 566   if (win)
 567     push_window(L, &win);
 568   else
 569     lua_pushnil(L);
 570   return 1;
 571 }
 572
 573 static const struct Xet_reg canvas_getters[] = {
 574   {"next", get_canvas, offsetof(struct canvas, c_next)},
 575   {"xoff", get_int, offsetof(struct canvas, c_xoff)},
 576   {"yoff", get_int, offsetof(struct canvas, c_yoff)},
 577   {"xs", get_int, offsetof(struct canvas, c_xs)},
 578   {"ys", get_int, offsetof(struct canvas, c_ys)},
 579   {"xe", get_int, offsetof(struct canvas, c_xe)},
 580   {"ye", get_int, offsetof(struct canvas, c_ye)},
 581   {"window", 0, 0, canvas_get_window},
 582   {0, 0}
 583 };
 584
 585 /** }}} */
 586
 587 /** Layout {{{ */
 588
 589 PUSH_TYPE(layout, struct layout)
 590 CHECK_TYPE(layout, struct layout)
 591
 592 static const struct Xet_reg layout_getters[] = {
 593       {0,0}
 594 };
 595
 596 static int
 597 get_layout(lua_State *L, void *v)
 598 {
 599   push_layout(L, (struct layout **)v);
 600   return 1;
 601 }
 602
 603 /** }}} */
 604
 605 /** Display {{{ */
 606
 607 PUSH_TYPE(display, struct display)
 608
 609 CHECK_TYPE(display, struct display)
 610
 611 static int
 612 display_get_canvases(lua_State *L)
 613 {
 614   struct display *d;
 615   struct canvas *iter;
 616   int count;
 617
 618   d = check_display(L, 1);
 619   lua_newtable(L);
 620   for (iter = d->d_cvlist, count = 0; iter; iter = iter->c_next, count++) {
 621     lua_pushinteger(L, count);
 622     push_canvas(L, &iter);
 623     lua_settable(L, -3);
 624   }
 625
 626   return 1;
 627 }
 628
 629 static const luaL_reg display_methods[] = {
 630   {"get_canvases", display_get_canvases},
 631   {0, 0}
 632 };
 633
 634 static int
 635 display_tostring(lua_State *L)
 636 {
 637   char str[128];
 638   struct display *d = check_display(L, 1);
 639   snprintf(str, sizeof(str), "{display: tty = '%s', term = '%s'}", d->d_usertty, d->d_termname);
 640   lua_pushstring(L, str);
 641   return 1;
 642 }
 643
 644 static const luaL_reg display_metamethods[] = {
 645   {"__tostring", display_tostring},
 646   {0, 0}
 647 };
 648
 649 static const struct Xet_reg display_setters[] = {
 650   {0, 0}
 651 };
 652
 653 static const struct Xet_reg display_getters[] = {
 654   {"tty", get_string, offsetof(struct display, d_usertty)},
 655   {"term", get_string, offsetof(struct display, d_termname)},
 656   {"fore", get_window, offsetof(struct display, d_fore)},
 657   {"other", get_window, offsetof(struct display, d_other)},
 658   {"width", get_int, offsetof(struct display, d_width)},
 659   {"height", get_int, offsetof(struct display, d_height)},
 660   {"user", get_user, offsetof(struct display, d_user)},
 661   {"layout", get_layout, offsetof(struct display, d_layout)},
 662   {0, 0}
 663 };
 664
 665 /** }}} */
 666
 667 /** Screen {{{ */
 668
 669 static int
 670 screen_get_windows(lua_State *L)
 671 {
 672   struct win *iter;
 673   int count;
 674
 675   lua_newtable(L);
 676   for (iter = windows, count = 0; iter; iter = iter->w_next, count++) {
 677     lua_pushinteger(L, iter->w_number);
 678     push_window(L, &iter);
 679     lua_settable(L, -3);
 680   }
 681
 682   return 1;
 683 }
 684
 685 static int
 686 screen_get_displays(lua_State *L)
 687 {
 688   struct display *iter;
 689   int count;
 690
 691   lua_newtable(L);
 692   for (iter = displays, count = 0; iter; iter = iter->d_next, count++) {
 693     lua_pushinteger(L, count);
 694     push_display(L, &iter);
 695     lua_settable(L, -3);
 696   }
 697
 698   return 1;
 699 }
 700
 701 static int
 702 screen_get_display(lua_State *L)
 703 {
 704   push_display(L, &display);
 705   return 1;
 706 }
 707
 708 static int
 709 screen_exec_command(lua_State *L)
 710 {
 711   const char *command;
 712   unsigned int len;
 713
 714   command = luaL_checklstring(L, 1, &len);
 715   if (command)
 716     RcLine((char *)command, len);
 717
 718   return 0;
 719 }
 720
 721 static int
 722 screen_append_msg(lua_State *L)
 723 {
 724   const char *msg, *color;
 725   unsigned int len;
 726   msg = luaL_checklstring(L, 1, &len);
 727   if (lua_isnil(L, 2))
 728     color = NULL;
 729   else
 730     color = luaL_checklstring(L, 2, &len);
 731   AppendWinMsgRend(msg, color);
 732   return 0;
 733 }
 734
 735 struct sinput_data
 736 {
 737   lua_State *L;
 738   lua_handler lh;
 739 };
 740
 741 void
 742 script_input_fn(char *buf, int len, char *priv)
 743 {
 744   struct sinput_data *sidata = (struct sinput_data *)priv;
 745   lua_handler lh = sidata->lh;
 746   lua_State *L = sidata->L;
 747
 748   LuaPushHandler(L, lh);
 749   lua_pushstring(L, buf);
 750   if (lua_pcall(L, 1, 0, 0) == LUA_ERRRUN)
 751     {
 752       if(lua_isstring(L, -1))
 753         {
 754           LuaShowErr(L);
 755         }
 756     }
 757   free(sidata);
 758   LuaFreeHandler(L, &lh);
 759 }
 760
 761 static int
 762 screen_input(lua_State *L)
 763 {
 764   char * prompt = NULL;
 765   lua_handler lh;
 766   struct sinput_data *sidata;
 767
 768   prompt = (char *)luaL_checkstring(L, 1);
 769   lh = LuaCheckHandler(L, 2, 1);
 770   sidata = (struct sinput_data *)malloc(sizeof(struct sinput_data));
 771   if (!sidata)
 772     luaL_error(L, "Out of Memory");
 773
 774   sidata->L = L;
 775   sidata->lh = lh;
 776   Input(prompt, 100, INP_COOKED, script_input_fn, (char *)sidata, 0);
 777
 778   return 0;
 779 }
 780
 781 static const luaL_reg screen_methods[] = {
 782   {"windows", screen_get_windows},
 783   {"displays", screen_get_displays},
 784   {"display", screen_get_display},
 785   {"command", screen_exec_command},
 786   {"append_msg", screen_append_msg},
 787   {"hook", LuaRegEvent},
 788   {"input", screen_input},
 789   {0, 0}
 790 };
 791
 792 static const luaL_reg screen_metamethods[] = {
 793   {0, 0}
 794 };
 795
 796 static const struct Xet_reg screen_setters[] = {
 797   {0, 0}
 798 };
 799
 800 static const struct Xet_reg screen_getters[] = {
 801   {0, 0}
 802 };
 803
 804 /** }}} */
 805
 806 /** Public functions {{{ */
 807
 808 /* FIXME: Think about this: will it affect the registered handlers?*/
 809 static lua_State *L;
 810 int LuaInit(void)
 811 {
 812   L = luaL_newstate();
 813
 814   luaL_openlibs(L);
 815
 816 #define REGISTER(X) struct_register(L, #X , X ## _methods, X##_metamethods, X##_setters, X##_getters)
 817
 818   REGISTER(screen);
 819   REGISTER(window);
 820   REGISTER(display);
 821   REGISTER(user);
 822   REGISTER(canvas);
 823   REGISTER(callback);
 824
 825   /* To store handler funcs */
 826   luaL_getmetatable(L, "screen");
 827   /* _keyfunc[key]->func */
 828   lua_pushstring(L, "_funcreg");
 829   lua_newtable(L);
 830   lua_rawset(L, -3);
 831   lua_pop(L, 1);
 832
 833   return 0;
 834 }
 835
 836 /* An error message on top of the stack. */
 837 static void
 838 LuaShowErr(lua_State *L)
 839 {
 840   struct display *d = display;
 841   unsigned int len;
 842   const char *message = luaL_checklstring(L, -1, &len);
 843   LMsg(0, "%s", message ? message : "Unknown error");
 844   lua_pop(L, 1);
 845   display = d;
 846 }
 847
 848 struct fn_def
 849 {
 850   void (*push_fn)(lua_State *, void*);
 851   void *value;
 852 };
 853
 854 static int
 855 LuaCallProcess(const char *name, struct fn_def defs[])
 856 {
 857   int argc = 0;
 858
 859   lua_getfield(L, LUA_GLOBALSINDEX, name);
 860   if (lua_isnil(L, -1))
 861     {
 862       lua_pop(L,1);
 863       return 0;
 864     }
 865   for (argc = 0; defs[argc].push_fn; argc++)
 866     defs[argc].push_fn(L, defs[argc].value);
 867   if (lua_pcall(L, argc, 0, 0) == LUA_ERRRUN && lua_isstring(L, -1))
 868     {
 869       LuaShowErr(L);
 870       return 0;
 871     }
 872   return 1;
 873 }
 874
 875 int LuaSource(const char *file, int async)
 876 {
 877   if (!L)
 878     return 0;
 879   struct stat st;
 880   if (stat(file, &st) == -1)
 881     Msg(errno, "Error loading lua script file '%s'", file);
 882   else
 883     {
 884       int len = strlen(file);
 885       if (len < 4 || strncmp(file + len - 4, ".lua", 4) != 0)
 886         return 0;
 887       if (luaL_dofile(L, file) && lua_isstring(L, -1))
 888         {
 889           LuaShowErr(L);
 890           return 0;
 891         }
 892       return 1;
 893     }
 894   return 0;
 895 }
 896
 897 int LuaFinit(void)
 898 {
 899   if (!L)
 900     return 0;
 901   lua_close(L);
 902   L = (lua_State*)0;
 903   return 0;
 904 }
 905
 906 int
 907 LuaProcessCaption(const char *caption, struct win *win, int len)
 908 {
 909   if (!L)
 910     return 0;
 911   struct fn_def params[] = {
 912     {lua_pushstring, caption},
 913     {push_window, &win},
 914     {lua_pushinteger, len},
 915     {NULL, NULL}
 916   };
 917   return LuaCallProcess("process_caption", params);
 918 }
 919
 920 static void
 921 push_stringarray(lua_State *L, char **args)
 922 {
 923   int i;
 924   lua_newtable(L);
 925   for (i = 1; args && *args; i++) {
 926     lua_pushinteger(L, i);
 927     lua_pushstring(L, *args++);
 928     lua_settable(L, -3);
 929   }
 930 }
 931
 932 int
 933 LuaPushParams(lua_State *L, const char *params, va_list va)
 934 {
 935   int num = 0;
 936   while (*params)
 937     {
 938       switch (*params)
 939         {
 940         case 's':
 941           lua_pushstring(L, va_arg(va, char *));
 942           break;
 943         case 'S':
 944           push_stringarray(L, va_arg(va, char **));
 945           break;
 946         case 'i':
 947           lua_pushinteger(L, va_arg(va, int));
 948           break;
 949         case 'd':
 950           {
 951             struct display *d = va_arg(va, struct display *);
 952             push_display(L, &d);
 953             break;
 954           }
 955         }
 956       params++;
 957       num++;
 958     }
 959   return num;
 960 }
 961
 962 int LuaCall(const char *func, const char **argv)
 963 {
 964   int argc;
 965   if (!L)
 966     return 0;
 967
 968   StackDump(L, "Before LuaCall\n");
 969   lua_getfield(L, LUA_GLOBALSINDEX, func);
 970   if (lua_isnil(L, -1))
 971     {
 972       lua_pop(L, 1);
 973       lua_pushstring(L, "Could not find the script function\n");
 974       LuaShowErr(L);
 975       return 0;
 976     }
 977   for (argc = 0; *argv; argv++, argc++)
 978     {
 979       lua_pushstring(L, *argv);
 980     }
 981   if (lua_pcall(L, argc, 0, 0) == LUA_ERRRUN)
 982     {
 983       if(lua_isstring(L, -1))
 984         {
 985           StackDump(L, "After LuaCall\n");
 986           LuaShowErr(L);
 987           return 0;
 988         }
 989     }
 990   return 1;
 991 }
 992
 993 /*** Lua callback handler management {{{ */
 994
 995 int
 996 LuaPushHTable(lua_State *L, int screen, const char * t)
 997 {
 998   lua_pushstring(L, t);
 999   lua_rawget(L, screen);
1000   /* FIXME: Do we need to balance the stack here? */
1001   if (lua_isnil(L, -1))
1002     luaL_error(L, "Fatal! Fail to get function registeration table!");
1003   return lua_gettop(L);
1004 }
1005
1006 void
1007 LuaPushHandler(lua_State *L, lua_handler lh)
1008 {
1009   int funcreg;
1010   if (lh->type == LUA_HANDLER_TYPE_F)
1011     {
1012       luaL_getmetatable(L, "screen");
1013       funcreg = LuaPushHTable(L, lua_gettop(L), "_funcreg");
1014       lua_rawgeti(L, funcreg, lh->u.reference);
1015       lua_replace(L, -3);
1016       lua_pop(L, 1);
1017     }
1018   else
1019     {
1020       lua_getfield(L, LUA_GLOBALSINDEX, lh->u.name);
1021     }
1022 }
1023
1024 int
1025 LuaFuncKey(lua_State *L, int idx, int ref)
1026 {
1027   int key, funcreg, sc;
1028   luaL_getmetatable(L, "screen");
1029   sc = lua_gettop(L);
1030   funcreg = LuaPushHTable(L, sc, "_funcreg");
1031
1032   lua_pushvalue(L, idx);
1033   key = luaL_ref(L, funcreg);
1034   lua_pop(L, 2);
1035   return key;
1036 }
1037
1038 void
1039 LuaHUnRef(lua_State *L, int key)
1040 {
1041   int funcreg, sc;
1042   luaL_getmetatable(L, "screen");
1043   sc = lua_gettop(L);
1044   funcreg = LuaPushHTable(L, sc, "_funcreg");
1045   luaL_unref(L, funcreg, key);
1046 }
1047
1048 lua_handler
1049 LuaCheckHandler(lua_State *L, int idx, int ref)
1050 {
1051   int key;
1052   if (idx < 0)
1053     idx = lua_gettop(L) + 1 - idx;
1054
1055   if (lua_isstring(L, idx))
1056     {
1057       const char * handler;
1058       /* registered with func name.*/
1059       handler = luaL_checkstring(L, idx);
1060       lua_getfield(L, LUA_GLOBALSINDEX, handler);
1061       if (!lua_isfunction(L, -1))
1062         luaL_error(L, "The specified handler %s in param #%d is not a function", handler, idx);
1063       lua_pop(L, 1);
1064       return LuaAllocHandler(handler, 0);
1065     }
1066   else if (!lua_isfunction(L, idx))
1067     luaL_error(L, "Handler should be a function or the name of function");
1068
1069   key = LuaFuncKey(L, idx, ref);
1070   return LuaAllocHandler(NULL, key);
1071 }
1072
1073 /* }}} **/
1074
1075 static int
1076 LuaDispatch(void *handler, const char *params, va_list va)
1077 {
1078   lua_handler lh = (lua_handler)handler;
1079   int argc, retvalue;
1080
1081   StackDump(L, "before dispatch");
1082
1083   LuaPushHandler(L, lh);
1084   if (lua_isnil(L, -1))
1085     {
1086       lua_pop(L, 1);
1087       return 0;
1088     }
1089   argc = LuaPushParams(L, params, va);
1090
1091   if (lua_pcall(L, argc, 1, 0) == LUA_ERRRUN && lua_isstring(L, -1))
1092     {
1093       StackDump(L, "After LuaDispatch\n");
1094       LuaShowErr(L);
1095       return 0;
1096     }
1097   retvalue = lua_tonumber(L, -1);
1098   lua_pop(L, 1);
1099   return retvalue;
1100 }
1101
1102 int LuaForeWindowChanged(void)
1103 {
1104   struct fn_def params[] = {
1105         {push_display, &display},
1106         {push_window, display ? &D_fore : &fore},
1107         {NULL, NULL}
1108   };
1109   if (!L)
1110     return 0;
1111   return LuaCallProcess("fore_changed", params);
1112 }
1113
1114 #define SEVNAME_MAX 30
1115 static int
1116 LuaRegEvent(lua_State *L)
1117 {
1118   /* signature: hook(obj, event, handler, priv);
1119    *        or: hook(event, handler, priv)
1120    *   returns: A ticket for later unregister. */
1121   int idx = 1, argc = lua_gettop(L);
1122   unsigned int priv = 31; /* Default privilege */
1123   lua_handler lh;
1124
1125   char *obj = NULL;
1126   const char *objname = "global";
1127
1128   static char evbuf[SEVNAME_MAX];
1129   const char *event;
1130
1131   struct script_event *sev;
1132
1133   StackDump(L, "Before RegEvent\n");
1134
1135   /* Identify the object, if specified */
1136   if (luaL_getmetafield(L, 1, "_objname"))
1137     {
1138       objname = luaL_checkstring(L, -1);
1139       lua_pop(L, 1);
1140       if (!strcmp("screen", objname))
1141         objname = "global";
1142       else
1143         obj = *(char **)lua_touserdata(L, 1);
1144       idx++;
1145     }
1146
1147   event = luaL_checkstring(L, idx++);
1148   snprintf(evbuf, SEVNAME_MAX, "%s_%s", objname, event);
1149
1150   /* Check and get the handler */
1151   lh = LuaCheckHandler(L, idx++, 1);
1152   if (!lh)
1153     luaL_error(L, "Out of memory");
1154
1155   StackDump(L, "In RegEvent\n");
1156
1157   if (idx <= argc)
1158     priv = luaL_checkinteger(L, idx);
1159
1160   sev = object_get_event(obj, evbuf);
1161   if (sev)
1162     {
1163       struct listener *l;
1164       l = (struct listener *)malloc(sizeof(struct listener));
1165       if (!l)
1166         return luaL_error(L, "Out of memory");
1167       l->priv = priv;
1168       l->bd = &lua_binding;
1169       l->handler = (void *)lh;
1170       register_listener(sev, l);
1171       /* Return the ticket for un-register */
1172       push_callback(L, &l);
1173     }
1174   else
1175     return luaL_error(L, "Invalid event specified: %s for object %s", event, objname);
1176
1177   StackDump(L, "After RegEvent\n");
1178   return 1;
1179 }
1180
1181 /** }}} */
1182
1183 struct ScriptFuncs LuaFuncs =
1184 {
1185   LuaForeWindowChanged,
1186   LuaProcessCaption
1187 };
1188
1189 struct binding lua_binding =
1190 {
1191     "lua", /*name*/
1192     0,     /*inited*/
1193     0,     /*registered*/
1194     LuaInit,
1195     LuaFinit,
1196     LuaCall,
1197     LuaSource,
1198     LuaDispatch,
1199     0,     /*b_next*/
1200     &LuaFuncs
1201 };
1202