ba8b5c17 |
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 | |