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16a5fed6 | 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 = (short)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 = (short)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 = (lu_byte)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 = (unsigned short)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 |