| 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 | |