1 /* 2 ** $Id: ldo.c,v 2.108.1.3 2013/11/08 18:22:50 roberto Exp $ 3 ** Stack and Call structure of Lua 4 ** See Copyright Notice in lua.h 5 */ 6 7 8 #include <setjmp.h> 9 #include <stdlib.h> 10 #include <string.h> 11 12 #define ldo_c 13 #define LUA_CORE 14 15 #include "lua.h" 16 17 #include "lapi.h" 18 #include "ldebug.h" 19 #include "ldo.h" 20 #include "lfunc.h" 21 #include "lgc.h" 22 #include "lmem.h" 23 #include "lobject.h" 24 #include "lopcodes.h" 25 #include "lparser.h" 26 #include "lstate.h" 27 #include "lstring.h" 28 #include "ltable.h" 29 #include "ltm.h" 30 #include "lundump.h" 31 #include "lvm.h" 32 #include "lzio.h" 33 34 35 36 37 /* 38 ** {====================================================== 39 ** Error-recovery functions 40 ** ======================================================= 41 */ 42 43 /* 44 ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By 45 ** default, Lua handles errors with exceptions when compiling as 46 ** C++ code, with _longjmp/_setjmp when asked to use them, and with 47 ** longjmp/setjmp otherwise. 48 */ 49 #if !defined(LUAI_THROW) 50 51 #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) 52 /* C++ exceptions */ 53 #define LUAI_THROW(L,c) throw(c) 54 #define LUAI_TRY(L,c,a) \ 55 try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; } 56 #define luai_jmpbuf int /* dummy variable */ 57 58 #elif defined(LUA_USE_ULONGJMP) 59 /* in Unix, try _longjmp/_setjmp (more efficient) */ 60 #define LUAI_THROW(L,c) _longjmp((c)->b, 1) 61 #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a } 62 #define luai_jmpbuf jmp_buf 63 64 #else 65 /* default handling with long jumps */ 66 #define LUAI_THROW(L,c) longjmp((c)->b, 1) 67 #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } 68 #define luai_jmpbuf jmp_buf 69 70 #endif 71 72 #endif 73 74 75 76 /* chain list of long jump buffers */ 77 struct lua_longjmp { 78 struct lua_longjmp *previous; 79 luai_jmpbuf b; 80 volatile int status; /* error code */ 81 }; 82 83 84 static void seterrorobj (lua_State *L, int errcode, StkId oldtop) { 85 switch (errcode) { 86 case LUA_ERRMEM: { /* memory error? */ 87 setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */ 88 break; 89 } 90 case LUA_ERRERR: { 91 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); 92 break; 93 } 94 default: { 95 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ 96 break; 97 } 98 } 99 L->top = oldtop + 1; 100 } 101 102 103 l_noret luaD_throw (lua_State *L, int errcode) { 104 if (L->errorJmp) { /* thread has an error handler? */ 105 L->errorJmp->status = errcode; /* set status */ 106 LUAI_THROW(L, L->errorJmp); /* jump to it */ 107 } 108 else { /* thread has no error handler */ 109 L->status = cast_byte(errcode); /* mark it as dead */ 110 if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */ 111 setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */ 112 luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */ 113 } 114 else { /* no handler at all; abort */ 115 if (G(L)->panic) { /* panic function? */ 116 lua_unlock(L); 117 G(L)->panic(L); /* call it (last chance to jump out) */ 118 } 119 abort(); 120 } 121 } 122 } 123 124 125 int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { 126 unsigned short oldnCcalls = L->nCcalls; 127 struct lua_longjmp lj; 128 lj.status = LUA_OK; 129 lj.previous = L->errorJmp; /* chain new error handler */ 130 L->errorJmp = &lj; 131 LUAI_TRY(L, &lj, 132 (*f)(L, ud); 133 ); 134 L->errorJmp = lj.previous; /* restore old error handler */ 135 L->nCcalls = oldnCcalls; 136 return lj.status; 137 } 138 139 /* }====================================================== */ 140 141 142 static void correctstack (lua_State *L, TValue *oldstack) { 143 CallInfo *ci; 144 GCObject *up; 145 L->top = (L->top - oldstack) + L->stack; 146 for (up = L->openupval; up != NULL; up = up->gch.next) 147 gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; 148 for (ci = L->ci; ci != NULL; ci = ci->previous) { 149 ci->top = (ci->top - oldstack) + L->stack; 150 ci->func = (ci->func - oldstack) + L->stack; 151 if (isLua(ci)) 152 ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; 153 } 154 } 155 156 157 /* some space for error handling */ 158 #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) 159 160 161 void luaD_reallocstack (lua_State *L, int newsize) { 162 TValue *oldstack = L->stack; 163 int lim = L->stacksize; 164 lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); 165 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); 166 luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); 167 for (; lim < newsize; lim++) 168 setnilvalue(L->stack + lim); /* erase new segment */ 169 L->stacksize = newsize; 170 L->stack_last = L->stack + newsize - EXTRA_STACK; 171 correctstack(L, oldstack); 172 } 173 174 175 void luaD_growstack (lua_State *L, int n) { 176 int size = L->stacksize; 177 if (size > LUAI_MAXSTACK) /* error after extra size? */ 178 luaD_throw(L, LUA_ERRERR); 179 else { 180 int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; 181 int newsize = 2 * size; 182 if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; 183 if (newsize < needed) newsize = needed; 184 if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ 185 luaD_reallocstack(L, ERRORSTACKSIZE); 186 luaG_runerror(L, "stack overflow"); 187 } 188 else 189 luaD_reallocstack(L, newsize); 190 } 191 } 192 193 194 static int stackinuse (lua_State *L) { 195 CallInfo *ci; 196 StkId lim = L->top; 197 for (ci = L->ci; ci != NULL; ci = ci->previous) { 198 lua_assert(ci->top <= L->stack_last); 199 if (lim < ci->top) lim = ci->top; 200 } 201 return cast_int(lim - L->stack) + 1; /* part of stack in use */ 202 } 203 204 205 void luaD_shrinkstack (lua_State *L) { 206 int inuse = stackinuse(L); 207 int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; 208 if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; 209 if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */ 210 goodsize >= L->stacksize) /* would grow instead of shrink? */ 211 condmovestack(L); /* don't change stack (change only for debugging) */ 212 else 213 luaD_reallocstack(L, goodsize); /* shrink it */ 214 } 215 216 217 void luaD_hook (lua_State *L, int event, int line) { 218 lua_Hook hook = L->hook; 219 if (hook && L->allowhook) { 220 CallInfo *ci = L->ci; 221 ptrdiff_t top = savestack(L, L->top); 222 ptrdiff_t ci_top = savestack(L, ci->top); 223 lua_Debug ar; 224 ar.event = event; 225 ar.currentline = line; 226 ar.i_ci = ci; 227 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 228 ci->top = L->top + LUA_MINSTACK; 229 lua_assert(ci->top <= L->stack_last); 230 L->allowhook = 0; /* cannot call hooks inside a hook */ 231 ci->callstatus |= CIST_HOOKED; 232 lua_unlock(L); 233 (*hook)(L, &ar); 234 lua_lock(L); 235 lua_assert(!L->allowhook); 236 L->allowhook = 1; 237 ci->top = restorestack(L, ci_top); 238 L->top = restorestack(L, top); 239 ci->callstatus &= ~CIST_HOOKED; 240 } 241 } 242 243 244 static void callhook (lua_State *L, CallInfo *ci) { 245 int hook = LUA_HOOKCALL; 246 ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ 247 if (isLua(ci->previous) && 248 GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { 249 ci->callstatus |= CIST_TAIL; 250 hook = LUA_HOOKTAILCALL; 251 } 252 luaD_hook(L, hook, -1); 253 ci->u.l.savedpc--; /* correct 'pc' */ 254 } 255 256 257 static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { 258 int i; 259 int nfixargs = p->numparams; 260 StkId base, fixed; 261 lua_assert(actual >= nfixargs); 262 /* move fixed parameters to final position */ 263 luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ 264 fixed = L->top - actual; /* first fixed argument */ 265 base = L->top; /* final position of first argument */ 266 for (i=0; i<nfixargs; i++) { 267 setobjs2s(L, L->top++, fixed + i); 268 setnilvalue(fixed + i); 269 } 270 return base; 271 } 272 273 274 static StkId tryfuncTM (lua_State *L, StkId func) { 275 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); 276 StkId p; 277 ptrdiff_t funcr = savestack(L, func); 278 if (!ttisfunction(tm)) 279 luaG_typeerror(L, func, "call"); 280 /* Open a hole inside the stack at `func' */ 281 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); 282 incr_top(L); 283 func = restorestack(L, funcr); /* previous call may change stack */ 284 setobj2s(L, func, tm); /* tag method is the new function to be called */ 285 return func; 286 } 287 288 289 290 #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) 291 292 293 /* 294 ** returns true if function has been executed (C function) 295 */ 296 int luaD_precall (lua_State *L, StkId func, int nresults) { 297 lua_CFunction f; 298 CallInfo *ci; 299 int n; /* number of arguments (Lua) or returns (C) */ 300 ptrdiff_t funcr = savestack(L, func); 301 switch (ttype(func)) { 302 case LUA_TLCF: /* light C function */ 303 f = fvalue(func); 304 goto Cfunc; 305 case LUA_TCCL: { /* C closure */ 306 f = clCvalue(func)->f; 307 Cfunc: 308 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 309 ci = next_ci(L); /* now 'enter' new function */ 310 ci->nresults = nresults; 311 ci->func = restorestack(L, funcr); 312 ci->top = L->top + LUA_MINSTACK; 313 lua_assert(ci->top <= L->stack_last); 314 ci->callstatus = 0; 315 luaC_checkGC(L); /* stack grow uses memory */ 316 if (L->hookmask & LUA_MASKCALL) 317 luaD_hook(L, LUA_HOOKCALL, -1); 318 lua_unlock(L); 319 n = (*f)(L); /* do the actual call */ 320 lua_lock(L); 321 api_checknelems(L, n); 322 luaD_poscall(L, L->top - n); 323 return 1; 324 } 325 case LUA_TLCL: { /* Lua function: prepare its call */ 326 StkId base; 327 Proto *p = clLvalue(func)->p; 328 n = cast_int(L->top - func) - 1; /* number of real arguments */ 329 luaD_checkstack(L, p->maxstacksize); 330 for (; n < p->numparams; n++) 331 setnilvalue(L->top++); /* complete missing arguments */ 332 if (!p->is_vararg) { 333 func = restorestack(L, funcr); 334 base = func + 1; 335 } 336 else { 337 base = adjust_varargs(L, p, n); 338 func = restorestack(L, funcr); /* previous call can change stack */ 339 } 340 ci = next_ci(L); /* now 'enter' new function */ 341 ci->nresults = nresults; 342 ci->func = func; 343 ci->u.l.base = base; 344 ci->top = base + p->maxstacksize; 345 lua_assert(ci->top <= L->stack_last); 346 ci->u.l.savedpc = p->code; /* starting point */ 347 ci->callstatus = CIST_LUA; 348 L->top = ci->top; 349 luaC_checkGC(L); /* stack grow uses memory */ 350 if (L->hookmask & LUA_MASKCALL) 351 callhook(L, ci); 352 return 0; 353 } 354 default: { /* not a function */ 355 func = tryfuncTM(L, func); /* retry with 'function' tag method */ 356 return luaD_precall(L, func, nresults); /* now it must be a function */ 357 } 358 } 359 } 360 361 362 int luaD_poscall (lua_State *L, StkId firstResult) { 363 StkId res; 364 int wanted, i; 365 CallInfo *ci = L->ci; 366 if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { 367 if (L->hookmask & LUA_MASKRET) { 368 ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ 369 luaD_hook(L, LUA_HOOKRET, -1); 370 firstResult = restorestack(L, fr); 371 } 372 L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ 373 } 374 res = ci->func; /* res == final position of 1st result */ 375 wanted = ci->nresults; 376 L->ci = ci = ci->previous; /* back to caller */ 377 /* move results to correct place */ 378 for (i = wanted; i != 0 && firstResult < L->top; i--) 379 setobjs2s(L, res++, firstResult++); 380 while (i-- > 0) 381 setnilvalue(res++); 382 L->top = res; 383 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ 384 } 385 386 387 /* 388 ** Call a function (C or Lua). The function to be called is at *func. 389 ** The arguments are on the stack, right after the function. 390 ** When returns, all the results are on the stack, starting at the original 391 ** function position. 392 */ 393 void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { 394 if (++L->nCcalls >= LUAI_MAXCCALLS) { 395 if (L->nCcalls == LUAI_MAXCCALLS) 396 luaG_runerror(L, "C stack overflow"); 397 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) 398 luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ 399 } 400 if (!allowyield) L->nny++; 401 if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ 402 luaV_execute(L); /* call it */ 403 if (!allowyield) L->nny--; 404 L->nCcalls--; 405 } 406 407 408 static void finishCcall (lua_State *L) { 409 CallInfo *ci = L->ci; 410 int n; 411 lua_assert(ci->u.c.k != NULL); /* must have a continuation */ 412 lua_assert(L->nny == 0); 413 if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ 414 ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ 415 L->errfunc = ci->u.c.old_errfunc; 416 } 417 /* finish 'lua_callk'/'lua_pcall' */ 418 adjustresults(L, ci->nresults); 419 /* call continuation function */ 420 if (!(ci->callstatus & CIST_STAT)) /* no call status? */ 421 ci->u.c.status = LUA_YIELD; /* 'default' status */ 422 lua_assert(ci->u.c.status != LUA_OK); 423 ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED; 424 lua_unlock(L); 425 n = (*ci->u.c.k)(L); 426 lua_lock(L); 427 api_checknelems(L, n); 428 /* finish 'luaD_precall' */ 429 luaD_poscall(L, L->top - n); 430 } 431 432 433 static void unroll (lua_State *L, void *ud) { 434 UNUSED(ud); 435 for (;;) { 436 if (L->ci == &L->base_ci) /* stack is empty? */ 437 return; /* coroutine finished normally */ 438 if (!isLua(L->ci)) /* C function? */ 439 finishCcall(L); 440 else { /* Lua function */ 441 luaV_finishOp(L); /* finish interrupted instruction */ 442 luaV_execute(L); /* execute down to higher C 'boundary' */ 443 } 444 } 445 } 446 447 448 /* 449 ** check whether thread has a suspended protected call 450 */ 451 static CallInfo *findpcall (lua_State *L) { 452 CallInfo *ci; 453 for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ 454 if (ci->callstatus & CIST_YPCALL) 455 return ci; 456 } 457 return NULL; /* no pending pcall */ 458 } 459 460 461 static int recover (lua_State *L, int status) { 462 StkId oldtop; 463 CallInfo *ci = findpcall(L); 464 if (ci == NULL) return 0; /* no recovery point */ 465 /* "finish" luaD_pcall */ 466 oldtop = restorestack(L, ci->extra); 467 luaF_close(L, oldtop); 468 seterrorobj(L, status, oldtop); 469 L->ci = ci; 470 L->allowhook = ci->u.c.old_allowhook; 471 L->nny = 0; /* should be zero to be yieldable */ 472 luaD_shrinkstack(L); 473 L->errfunc = ci->u.c.old_errfunc; 474 ci->callstatus |= CIST_STAT; /* call has error status */ 475 ci->u.c.status = status; /* (here it is) */ 476 return 1; /* continue running the coroutine */ 477 } 478 479 480 /* 481 ** signal an error in the call to 'resume', not in the execution of the 482 ** coroutine itself. (Such errors should not be handled by any coroutine 483 ** error handler and should not kill the coroutine.) 484 */ 485 static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { 486 L->top = firstArg; /* remove args from the stack */ 487 setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ 488 api_incr_top(L); 489 luaD_throw(L, -1); /* jump back to 'lua_resume' */ 490 } 491 492 493 /* 494 ** do the work for 'lua_resume' in protected mode 495 */ 496 static void resume (lua_State *L, void *ud) { 497 int nCcalls = L->nCcalls; 498 StkId firstArg = cast(StkId, ud); 499 CallInfo *ci = L->ci; 500 if (nCcalls >= LUAI_MAXCCALLS) 501 resume_error(L, "C stack overflow", firstArg); 502 if (L->status == LUA_OK) { /* may be starting a coroutine */ 503 if (ci != &L->base_ci) /* not in base level? */ 504 resume_error(L, "cannot resume non-suspended coroutine", firstArg); 505 /* coroutine is in base level; start running it */ 506 if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ 507 luaV_execute(L); /* call it */ 508 } 509 else if (L->status != LUA_YIELD) 510 resume_error(L, "cannot resume dead coroutine", firstArg); 511 else { /* resuming from previous yield */ 512 L->status = LUA_OK; 513 ci->func = restorestack(L, ci->extra); 514 if (isLua(ci)) /* yielded inside a hook? */ 515 luaV_execute(L); /* just continue running Lua code */ 516 else { /* 'common' yield */ 517 if (ci->u.c.k != NULL) { /* does it have a continuation? */ 518 int n; 519 ci->u.c.status = LUA_YIELD; /* 'default' status */ 520 ci->callstatus |= CIST_YIELDED; 521 lua_unlock(L); 522 n = (*ci->u.c.k)(L); /* call continuation */ 523 lua_lock(L); 524 api_checknelems(L, n); 525 firstArg = L->top - n; /* yield results come from continuation */ 526 } 527 luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ 528 } 529 unroll(L, NULL); 530 } 531 lua_assert(nCcalls == L->nCcalls); 532 } 533 534 535 LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { 536 int status; 537 int oldnny = L->nny; /* save 'nny' */ 538 lua_lock(L); 539 luai_userstateresume(L, nargs); 540 L->nCcalls = (from) ? from->nCcalls + 1 : 1; 541 L->nny = 0; /* allow yields */ 542 api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); 543 status = luaD_rawrunprotected(L, resume, L->top - nargs); 544 if (status == -1) /* error calling 'lua_resume'? */ 545 status = LUA_ERRRUN; 546 else { /* yield or regular error */ 547 while (status != LUA_OK && status != LUA_YIELD) { /* error? */ 548 if (recover(L, status)) /* recover point? */ 549 status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */ 550 else { /* unrecoverable error */ 551 L->status = cast_byte(status); /* mark thread as `dead' */ 552 seterrorobj(L, status, L->top); 553 L->ci->top = L->top; 554 break; 555 } 556 } 557 lua_assert(status == L->status); 558 } 559 L->nny = oldnny; /* restore 'nny' */ 560 L->nCcalls--; 561 lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0)); 562 lua_unlock(L); 563 return status; 564 } 565 566 567 LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) { 568 CallInfo *ci = L->ci; 569 luai_userstateyield(L, nresults); 570 lua_lock(L); 571 api_checknelems(L, nresults); 572 if (L->nny > 0) { 573 if (L != G(L)->mainthread) 574 luaG_runerror(L, "attempt to yield across a C-call boundary"); 575 else 576 luaG_runerror(L, "attempt to yield from outside a coroutine"); 577 } 578 L->status = LUA_YIELD; 579 ci->extra = savestack(L, ci->func); /* save current 'func' */ 580 if (isLua(ci)) { /* inside a hook? */ 581 api_check(L, k == NULL, "hooks cannot continue after yielding"); 582 } 583 else { 584 if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ 585 ci->u.c.ctx = ctx; /* save context */ 586 ci->func = L->top - nresults - 1; /* protect stack below results */ 587 luaD_throw(L, LUA_YIELD); 588 } 589 lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ 590 lua_unlock(L); 591 return 0; /* return to 'luaD_hook' */ 592 } 593 594 595 int luaD_pcall (lua_State *L, Pfunc func, void *u, 596 ptrdiff_t old_top, ptrdiff_t ef) { 597 int status; 598 CallInfo *old_ci = L->ci; 599 lu_byte old_allowhooks = L->allowhook; 600 unsigned short old_nny = L->nny; 601 ptrdiff_t old_errfunc = L->errfunc; 602 L->errfunc = ef; 603 status = luaD_rawrunprotected(L, func, u); 604 if (status != LUA_OK) { /* an error occurred? */ 605 StkId oldtop = restorestack(L, old_top); 606 luaF_close(L, oldtop); /* close possible pending closures */ 607 seterrorobj(L, status, oldtop); 608 L->ci = old_ci; 609 L->allowhook = old_allowhooks; 610 L->nny = old_nny; 611 luaD_shrinkstack(L); 612 } 613 L->errfunc = old_errfunc; 614 return status; 615 } 616 617 618 619 /* 620 ** Execute a protected parser. 621 */ 622 struct SParser { /* data to `f_parser' */ 623 ZIO *z; 624 Mbuffer buff; /* dynamic structure used by the scanner */ 625 Dyndata dyd; /* dynamic structures used by the parser */ 626 const char *mode; 627 const char *name; 628 }; 629 630 631 static void checkmode (lua_State *L, const char *mode, const char *x) { 632 if (mode && strchr(mode, x[0]) == NULL) { 633 luaO_pushfstring(L, 634 "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode); 635 luaD_throw(L, LUA_ERRSYNTAX); 636 } 637 } 638 639 640 static void f_parser (lua_State *L, void *ud) { 641 int i; 642 Closure *cl; 643 struct SParser *p = cast(struct SParser *, ud); 644 int c = zgetc(p->z); /* read first character */ 645 if (c == LUA_SIGNATURE[0]) { 646 checkmode(L, p->mode, "binary"); 647 cl = luaU_undump(L, p->z, &p->buff, p->name); 648 } 649 else { 650 checkmode(L, p->mode, "text"); 651 cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); 652 } 653 lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues); 654 for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */ 655 UpVal *up = luaF_newupval(L); 656 cl->l.upvals[i] = up; 657 luaC_objbarrier(L, cl, up); 658 } 659 } 660 661 662 int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, 663 const char *mode) { 664 struct SParser p; 665 int status; 666 L->nny++; /* cannot yield during parsing */ 667 p.z = z; p.name = name; p.mode = mode; 668 p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; 669 p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; 670 p.dyd.label.arr = NULL; p.dyd.label.size = 0; 671 luaZ_initbuffer(L, &p.buff); 672 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); 673 luaZ_freebuffer(L, &p.buff); 674 luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); 675 luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); 676 luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); 677 L->nny--; 678 return status; 679 } 680 681 682