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| 1 /* |
| 2 ** $Id: ldo.c,v 2.108 2012/10/01 14:05:04 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 fixed = L->top - actual; /* first fixed argument */ |
| 264 base = L->top; /* final position of first argument */ |
| 265 for (i=0; i<nfixargs; i++) { |
| 266 setobjs2s(L, L->top++, fixed + i); |
| 267 setnilvalue(fixed + i); |
| 268 } |
| 269 return base; |
| 270 } |
| 271 |
| 272 |
| 273 static StkId tryfuncTM (lua_State *L, StkId func) { |
| 274 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); |
| 275 StkId p; |
| 276 ptrdiff_t funcr = savestack(L, func); |
| 277 if (!ttisfunction(tm)) |
| 278 luaG_typeerror(L, func, "call"); |
| 279 /* Open a hole inside the stack at `func' */ |
| 280 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); |
| 281 incr_top(L); |
| 282 func = restorestack(L, funcr); /* previous call may change stack */ |
| 283 setobj2s(L, func, tm); /* tag method is the new function to be called */ |
| 284 return func; |
| 285 } |
| 286 |
| 287 |
| 288 |
| 289 #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) |
| 290 |
| 291 |
| 292 /* |
| 293 ** returns true if function has been executed (C function) |
| 294 */ |
| 295 int luaD_precall (lua_State *L, StkId func, int nresults) { |
| 296 lua_CFunction f; |
| 297 CallInfo *ci; |
| 298 int n; /* number of arguments (Lua) or returns (C) */ |
| 299 ptrdiff_t funcr = savestack(L, func); |
| 300 switch (ttype(func)) { |
| 301 case LUA_TLCF: /* light C function */ |
| 302 f = fvalue(func); |
| 303 goto Cfunc; |
| 304 case LUA_TCCL: { /* C closure */ |
| 305 f = clCvalue(func)->f; |
| 306 Cfunc: |
| 307 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ |
| 308 ci = next_ci(L); /* now 'enter' new function */ |
| 309 ci->nresults = nresults; |
| 310 ci->func = restorestack(L, funcr); |
| 311 ci->top = L->top + LUA_MINSTACK; |
| 312 lua_assert(ci->top <= L->stack_last); |
| 313 ci->callstatus = 0; |
| 314 luaC_checkGC(L); /* stack grow uses memory */ |
| 315 if (L->hookmask & LUA_MASKCALL) |
| 316 luaD_hook(L, LUA_HOOKCALL, -1); |
| 317 lua_unlock(L); |
| 318 n = (*f)(L); /* do the actual call */ |
| 319 lua_lock(L); |
| 320 api_checknelems(L, n); |
| 321 luaD_poscall(L, L->top - n); |
| 322 return 1; |
| 323 } |
| 324 case LUA_TLCL: { /* Lua function: prepare its call */ |
| 325 StkId base; |
| 326 Proto *p = clLvalue(func)->p; |
| 327 luaD_checkstack(L, p->maxstacksize); |
| 328 func = restorestack(L, funcr); |
| 329 n = cast_int(L->top - func) - 1; /* number of real arguments */ |
| 330 for (; n < p->numparams; n++) |
| 331 setnilvalue(L->top++); /* complete missing arguments */ |
| 332 base = (!p->is_vararg) ? func + 1 : adjust_varargs(L, p, n); |
| 333 ci = next_ci(L); /* now 'enter' new function */ |
| 334 ci->nresults = nresults; |
| 335 ci->func = func; |
| 336 ci->u.l.base = base; |
| 337 ci->top = base + p->maxstacksize; |
| 338 lua_assert(ci->top <= L->stack_last); |
| 339 ci->u.l.savedpc = p->code; /* starting point */ |
| 340 ci->callstatus = CIST_LUA; |
| 341 L->top = ci->top; |
| 342 luaC_checkGC(L); /* stack grow uses memory */ |
| 343 if (L->hookmask & LUA_MASKCALL) |
| 344 callhook(L, ci); |
| 345 return 0; |
| 346 } |
| 347 default: { /* not a function */ |
| 348 func = tryfuncTM(L, func); /* retry with 'function' tag method */ |
| 349 return luaD_precall(L, func, nresults); /* now it must be a function */ |
| 350 } |
| 351 } |
| 352 } |
| 353 |
| 354 |
| 355 int luaD_poscall (lua_State *L, StkId firstResult) { |
| 356 StkId res; |
| 357 int wanted, i; |
| 358 CallInfo *ci = L->ci; |
| 359 if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { |
| 360 if (L->hookmask & LUA_MASKRET) { |
| 361 ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ |
| 362 luaD_hook(L, LUA_HOOKRET, -1); |
| 363 firstResult = restorestack(L, fr); |
| 364 } |
| 365 L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ |
| 366 } |
| 367 res = ci->func; /* res == final position of 1st result */ |
| 368 wanted = ci->nresults; |
| 369 L->ci = ci = ci->previous; /* back to caller */ |
| 370 /* move results to correct place */ |
| 371 for (i = wanted; i != 0 && firstResult < L->top; i--) |
| 372 setobjs2s(L, res++, firstResult++); |
| 373 while (i-- > 0) |
| 374 setnilvalue(res++); |
| 375 L->top = res; |
| 376 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ |
| 377 } |
| 378 |
| 379 |
| 380 /* |
| 381 ** Call a function (C or Lua). The function to be called is at *func. |
| 382 ** The arguments are on the stack, right after the function. |
| 383 ** When returns, all the results are on the stack, starting at the original |
| 384 ** function position. |
| 385 */ |
| 386 void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { |
| 387 if (++L->nCcalls >= LUAI_MAXCCALLS) { |
| 388 if (L->nCcalls == LUAI_MAXCCALLS) |
| 389 luaG_runerror(L, "C stack overflow"); |
| 390 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) |
| 391 luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ |
| 392 } |
| 393 if (!allowyield) L->nny++; |
| 394 if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ |
| 395 luaV_execute(L); /* call it */ |
| 396 if (!allowyield) L->nny--; |
| 397 L->nCcalls--; |
| 398 } |
| 399 |
| 400 |
| 401 static void finishCcall (lua_State *L) { |
| 402 CallInfo *ci = L->ci; |
| 403 int n; |
| 404 lua_assert(ci->u.c.k != NULL); /* must have a continuation */ |
| 405 lua_assert(L->nny == 0); |
| 406 if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ |
| 407 ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ |
| 408 L->errfunc = ci->u.c.old_errfunc; |
| 409 } |
| 410 /* finish 'lua_callk'/'lua_pcall' */ |
| 411 adjustresults(L, ci->nresults); |
| 412 /* call continuation function */ |
| 413 if (!(ci->callstatus & CIST_STAT)) /* no call status? */ |
| 414 ci->u.c.status = LUA_YIELD; /* 'default' status */ |
| 415 lua_assert(ci->u.c.status != LUA_OK); |
| 416 ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED; |
| 417 lua_unlock(L); |
| 418 n = (*ci->u.c.k)(L); |
| 419 lua_lock(L); |
| 420 api_checknelems(L, n); |
| 421 /* finish 'luaD_precall' */ |
| 422 luaD_poscall(L, L->top - n); |
| 423 } |
| 424 |
| 425 |
| 426 static void unroll (lua_State *L, void *ud) { |
| 427 UNUSED(ud); |
| 428 for (;;) { |
| 429 if (L->ci == &L->base_ci) /* stack is empty? */ |
| 430 return; /* coroutine finished normally */ |
| 431 if (!isLua(L->ci)) /* C function? */ |
| 432 finishCcall(L); |
| 433 else { /* Lua function */ |
| 434 luaV_finishOp(L); /* finish interrupted instruction */ |
| 435 luaV_execute(L); /* execute down to higher C 'boundary' */ |
| 436 } |
| 437 } |
| 438 } |
| 439 |
| 440 |
| 441 /* |
| 442 ** check whether thread has a suspended protected call |
| 443 */ |
| 444 static CallInfo *findpcall (lua_State *L) { |
| 445 CallInfo *ci; |
| 446 for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ |
| 447 if (ci->callstatus & CIST_YPCALL) |
| 448 return ci; |
| 449 } |
| 450 return NULL; /* no pending pcall */ |
| 451 } |
| 452 |
| 453 |
| 454 static int recover (lua_State *L, int status) { |
| 455 StkId oldtop; |
| 456 CallInfo *ci = findpcall(L); |
| 457 if (ci == NULL) return 0; /* no recovery point */ |
| 458 /* "finish" luaD_pcall */ |
| 459 oldtop = restorestack(L, ci->extra); |
| 460 luaF_close(L, oldtop); |
| 461 seterrorobj(L, status, oldtop); |
| 462 L->ci = ci; |
| 463 L->allowhook = ci->u.c.old_allowhook; |
| 464 L->nny = 0; /* should be zero to be yieldable */ |
| 465 luaD_shrinkstack(L); |
| 466 L->errfunc = ci->u.c.old_errfunc; |
| 467 ci->callstatus |= CIST_STAT; /* call has error status */ |
| 468 ci->u.c.status = status; /* (here it is) */ |
| 469 return 1; /* continue running the coroutine */ |
| 470 } |
| 471 |
| 472 |
| 473 /* |
| 474 ** signal an error in the call to 'resume', not in the execution of the |
| 475 ** coroutine itself. (Such errors should not be handled by any coroutine |
| 476 ** error handler and should not kill the coroutine.) |
| 477 */ |
| 478 static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { |
| 479 L->top = firstArg; /* remove args from the stack */ |
| 480 setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ |
| 481 api_incr_top(L); |
| 482 luaD_throw(L, -1); /* jump back to 'lua_resume' */ |
| 483 } |
| 484 |
| 485 |
| 486 /* |
| 487 ** do the work for 'lua_resume' in protected mode |
| 488 */ |
| 489 static void resume (lua_State *L, void *ud) { |
| 490 int nCcalls = L->nCcalls; |
| 491 StkId firstArg = cast(StkId, ud); |
| 492 CallInfo *ci = L->ci; |
| 493 if (nCcalls >= LUAI_MAXCCALLS) |
| 494 resume_error(L, "C stack overflow", firstArg); |
| 495 if (L->status == LUA_OK) { /* may be starting a coroutine */ |
| 496 if (ci != &L->base_ci) /* not in base level? */ |
| 497 resume_error(L, "cannot resume non-suspended coroutine", firstArg); |
| 498 /* coroutine is in base level; start running it */ |
| 499 if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ |
| 500 luaV_execute(L); /* call it */ |
| 501 } |
| 502 else if (L->status != LUA_YIELD) |
| 503 resume_error(L, "cannot resume dead coroutine", firstArg); |
| 504 else { /* resuming from previous yield */ |
| 505 L->status = LUA_OK; |
| 506 ci->func = restorestack(L, ci->extra); |
| 507 if (isLua(ci)) /* yielded inside a hook? */ |
| 508 luaV_execute(L); /* just continue running Lua code */ |
| 509 else { /* 'common' yield */ |
| 510 if (ci->u.c.k != NULL) { /* does it have a continuation? */ |
| 511 int n; |
| 512 ci->u.c.status = LUA_YIELD; /* 'default' status */ |
| 513 ci->callstatus |= CIST_YIELDED; |
| 514 lua_unlock(L); |
| 515 n = (*ci->u.c.k)(L); /* call continuation */ |
| 516 lua_lock(L); |
| 517 api_checknelems(L, n); |
| 518 firstArg = L->top - n; /* yield results come from continuation */ |
| 519 } |
| 520 luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ |
| 521 } |
| 522 unroll(L, NULL); |
| 523 } |
| 524 lua_assert(nCcalls == L->nCcalls); |
| 525 } |
| 526 |
| 527 |
| 528 LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { |
| 529 int status; |
| 530 lua_lock(L); |
| 531 luai_userstateresume(L, nargs); |
| 532 L->nCcalls = (from) ? from->nCcalls + 1 : 1; |
| 533 L->nny = 0; /* allow yields */ |
| 534 api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); |
| 535 status = luaD_rawrunprotected(L, resume, L->top - nargs); |
| 536 if (status == -1) /* error calling 'lua_resume'? */ |
| 537 status = LUA_ERRRUN; |
| 538 else { /* yield or regular error */ |
| 539 while (status != LUA_OK && status != LUA_YIELD) { /* error? */ |
| 540 if (recover(L, status)) /* recover point? */ |
| 541 status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */ |
| 542 else { /* unrecoverable error */ |
| 543 L->status = cast_byte(status); /* mark thread as `dead' */ |
| 544 seterrorobj(L, status, L->top); |
| 545 L->ci->top = L->top; |
| 546 break; |
| 547 } |
| 548 } |
| 549 lua_assert(status == L->status); |
| 550 } |
| 551 L->nny = 1; /* do not allow yields */ |
| 552 L->nCcalls--; |
| 553 lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0)); |
| 554 lua_unlock(L); |
| 555 return status; |
| 556 } |
| 557 |
| 558 |
| 559 LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) { |
| 560 CallInfo *ci = L->ci; |
| 561 luai_userstateyield(L, nresults); |
| 562 lua_lock(L); |
| 563 api_checknelems(L, nresults); |
| 564 if (L->nny > 0) { |
| 565 if (L != G(L)->mainthread) |
| 566 luaG_runerror(L, "attempt to yield across a C-call boundary"); |
| 567 else |
| 568 luaG_runerror(L, "attempt to yield from outside a coroutine"); |
| 569 } |
| 570 L->status = LUA_YIELD; |
| 571 ci->extra = savestack(L, ci->func); /* save current 'func' */ |
| 572 if (isLua(ci)) { /* inside a hook? */ |
| 573 api_check(L, k == NULL, "hooks cannot continue after yielding"); |
| 574 } |
| 575 else { |
| 576 if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ |
| 577 ci->u.c.ctx = ctx; /* save context */ |
| 578 ci->func = L->top - nresults - 1; /* protect stack below results */ |
| 579 luaD_throw(L, LUA_YIELD); |
| 580 } |
| 581 lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ |
| 582 lua_unlock(L); |
| 583 return 0; /* return to 'luaD_hook' */ |
| 584 } |
| 585 |
| 586 |
| 587 int luaD_pcall (lua_State *L, Pfunc func, void *u, |
| 588 ptrdiff_t old_top, ptrdiff_t ef) { |
| 589 int status; |
| 590 CallInfo *old_ci = L->ci; |
| 591 lu_byte old_allowhooks = L->allowhook; |
| 592 unsigned short old_nny = L->nny; |
| 593 ptrdiff_t old_errfunc = L->errfunc; |
| 594 L->errfunc = ef; |
| 595 status = luaD_rawrunprotected(L, func, u); |
| 596 if (status != LUA_OK) { /* an error occurred? */ |
| 597 StkId oldtop = restorestack(L, old_top); |
| 598 luaF_close(L, oldtop); /* close possible pending closures */ |
| 599 seterrorobj(L, status, oldtop); |
| 600 L->ci = old_ci; |
| 601 L->allowhook = old_allowhooks; |
| 602 L->nny = old_nny; |
| 603 luaD_shrinkstack(L); |
| 604 } |
| 605 L->errfunc = old_errfunc; |
| 606 return status; |
| 607 } |
| 608 |
| 609 |
| 610 |
| 611 /* |
| 612 ** Execute a protected parser. |
| 613 */ |
| 614 struct SParser { /* data to `f_parser' */ |
| 615 ZIO *z; |
| 616 Mbuffer buff; /* dynamic structure used by the scanner */ |
| 617 Dyndata dyd; /* dynamic structures used by the parser */ |
| 618 const char *mode; |
| 619 const char *name; |
| 620 }; |
| 621 |
| 622 |
| 623 static void checkmode (lua_State *L, const char *mode, const char *x) { |
| 624 if (mode && strchr(mode, x[0]) == NULL) { |
| 625 luaO_pushfstring(L, |
| 626 "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode); |
| 627 luaD_throw(L, LUA_ERRSYNTAX); |
| 628 } |
| 629 } |
| 630 |
| 631 |
| 632 static void f_parser (lua_State *L, void *ud) { |
| 633 int i; |
| 634 Closure *cl; |
| 635 struct SParser *p = cast(struct SParser *, ud); |
| 636 int c = zgetc(p->z); /* read first character */ |
| 637 if (c == LUA_SIGNATURE[0]) { |
| 638 checkmode(L, p->mode, "binary"); |
| 639 cl = luaU_undump(L, p->z, &p->buff, p->name); |
| 640 } |
| 641 else { |
| 642 checkmode(L, p->mode, "text"); |
| 643 cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); |
| 644 } |
| 645 lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues); |
| 646 for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */ |
| 647 UpVal *up = luaF_newupval(L); |
| 648 cl->l.upvals[i] = up; |
| 649 luaC_objbarrier(L, cl, up); |
| 650 } |
| 651 } |
| 652 |
| 653 |
| 654 int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, |
| 655 const char *mode) { |
| 656 struct SParser p; |
| 657 int status; |
| 658 L->nny++; /* cannot yield during parsing */ |
| 659 p.z = z; p.name = name; p.mode = mode; |
| 660 p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; |
| 661 p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; |
| 662 p.dyd.label.arr = NULL; p.dyd.label.size = 0; |
| 663 luaZ_initbuffer(L, &p.buff); |
| 664 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); |
| 665 luaZ_freebuffer(L, &p.buff); |
| 666 luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); |
| 667 luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); |
| 668 luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); |
| 669 L->nny--; |
| 670 return status; |
| 671 } |
| 672 |
| 673 |
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