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authorLi Jin <dragon-fly@qq.com>2020-06-22 16:50:40 +0800
committerLi Jin <dragon-fly@qq.com>2020-06-22 16:50:40 +0800
commitcd2b60b101a398cb9356d746364e70eaed1860f1 (patch)
treea1fe71b76faabc4883f16905a94164ce5c23e692 /src/lua/ldo.c
parent88c1052e700f38cf3d8ad82d469da4c487760b7e (diff)
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add support for local variable declared with attribute 'close' and 'const' for Lua 5.4.
Diffstat (limited to 'src/lua/ldo.c')
-rw-r--r--src/lua/ldo.c822
1 files changed, 822 insertions, 0 deletions
diff --git a/src/lua/ldo.c b/src/lua/ldo.c
new file mode 100644
index 0000000..c563b1d
--- /dev/null
+++ b/src/lua/ldo.c
@@ -0,0 +1,822 @@
1/*
2** $Id: ldo.c $
3** Stack and Call structure of Lua
4** See Copyright Notice in lua.h
5*/
6
7#define ldo_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <setjmp.h>
14#include <stdlib.h>
15#include <string.h>
16
17#include "lua.h"
18
19#include "lapi.h"
20#include "ldebug.h"
21#include "ldo.h"
22#include "lfunc.h"
23#include "lgc.h"
24#include "lmem.h"
25#include "lobject.h"
26#include "lopcodes.h"
27#include "lparser.h"
28#include "lstate.h"
29#include "lstring.h"
30#include "ltable.h"
31#include "ltm.h"
32#include "lundump.h"
33#include "lvm.h"
34#include "lzio.h"
35
36
37
38#define errorstatus(s) ((s) > LUA_YIELD)
39
40
41/*
42** {======================================================
43** Error-recovery functions
44** =======================================================
45*/
46
47/*
48** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By
49** default, Lua handles errors with exceptions when compiling as
50** C++ code, with _longjmp/_setjmp when asked to use them, and with
51** longjmp/setjmp otherwise.
52*/
53#if !defined(LUAI_THROW) /* { */
54
55#if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) /* { */
56
57/* C++ exceptions */
58#define LUAI_THROW(L,c) throw(c)
59#define LUAI_TRY(L,c,a) \
60 try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; }
61#define luai_jmpbuf int /* dummy variable */
62
63#elif defined(LUA_USE_POSIX) /* }{ */
64
65/* in POSIX, try _longjmp/_setjmp (more efficient) */
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#else /* }{ */
71
72/* ISO C handling with long jumps */
73#define LUAI_THROW(L,c) longjmp((c)->b, 1)
74#define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a }
75#define luai_jmpbuf jmp_buf
76
77#endif /* } */
78
79#endif /* } */
80
81
82
83/* chain list of long jump buffers */
84struct lua_longjmp {
85 struct lua_longjmp *previous;
86 luai_jmpbuf b;
87 volatile int status; /* error code */
88};
89
90
91void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) {
92 switch (errcode) {
93 case LUA_ERRMEM: { /* memory error? */
94 setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
95 break;
96 }
97 case LUA_ERRERR: {
98 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
99 break;
100 }
101 case CLOSEPROTECT: {
102 setnilvalue(s2v(oldtop)); /* no error message */
103 break;
104 }
105 default: {
106 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
107 break;
108 }
109 }
110 L->top = oldtop + 1;
111}
112
113
114l_noret luaD_throw (lua_State *L, int errcode) {
115 if (L->errorJmp) { /* thread has an error handler? */
116 L->errorJmp->status = errcode; /* set status */
117 LUAI_THROW(L, L->errorJmp); /* jump to it */
118 }
119 else { /* thread has no error handler */
120 global_State *g = G(L);
121 errcode = luaF_close(L, L->stack, errcode); /* close all upvalues */
122 L->status = cast_byte(errcode); /* mark it as dead */
123 if (g->mainthread->errorJmp) { /* main thread has a handler? */
124 setobjs2s(L, g->mainthread->top++, L->top - 1); /* copy error obj. */
125 luaD_throw(g->mainthread, errcode); /* re-throw in main thread */
126 }
127 else { /* no handler at all; abort */
128 if (g->panic) { /* panic function? */
129 luaD_seterrorobj(L, errcode, L->top); /* assume EXTRA_STACK */
130 if (L->ci->top < L->top)
131 L->ci->top = L->top; /* pushing msg. can break this invariant */
132 lua_unlock(L);
133 g->panic(L); /* call panic function (last chance to jump out) */
134 }
135 abort();
136 }
137 }
138}
139
140
141int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
142 global_State *g = G(L);
143 l_uint32 oldnCcalls = g->Cstacklimit - (L->nCcalls + L->nci);
144 struct lua_longjmp lj;
145 lj.status = LUA_OK;
146 lj.previous = L->errorJmp; /* chain new error handler */
147 L->errorJmp = &lj;
148 LUAI_TRY(L, &lj,
149 (*f)(L, ud);
150 );
151 L->errorJmp = lj.previous; /* restore old error handler */
152 L->nCcalls = g->Cstacklimit - oldnCcalls - L->nci;
153 return lj.status;
154}
155
156/* }====================================================== */
157
158
159/*
160** {==================================================================
161** Stack reallocation
162** ===================================================================
163*/
164static void correctstack (lua_State *L, StkId oldstack, StkId newstack) {
165 CallInfo *ci;
166 UpVal *up;
167 if (oldstack == newstack)
168 return; /* stack address did not change */
169 L->top = (L->top - oldstack) + newstack;
170 for (up = L->openupval; up != NULL; up = up->u.open.next)
171 up->v = s2v((uplevel(up) - oldstack) + newstack);
172 for (ci = L->ci; ci != NULL; ci = ci->previous) {
173 ci->top = (ci->top - oldstack) + newstack;
174 ci->func = (ci->func - oldstack) + newstack;
175 if (isLua(ci))
176 ci->u.l.trap = 1; /* signal to update 'trap' in 'luaV_execute' */
177 }
178}
179
180
181/* some space for error handling */
182#define ERRORSTACKSIZE (LUAI_MAXSTACK + 200)
183
184
185int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) {
186 int lim = L->stacksize;
187 StkId newstack = luaM_reallocvector(L, L->stack, lim, newsize, StackValue);
188 lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
189 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
190 if (unlikely(newstack == NULL)) { /* reallocation failed? */
191 if (raiseerror)
192 luaM_error(L);
193 else return 0; /* do not raise an error */
194 }
195 for (; lim < newsize; lim++)
196 setnilvalue(s2v(newstack + lim)); /* erase new segment */
197 correctstack(L, L->stack, newstack);
198 L->stack = newstack;
199 L->stacksize = newsize;
200 L->stack_last = L->stack + newsize - EXTRA_STACK;
201 return 1;
202}
203
204
205/*
206** Try to grow the stack by at least 'n' elements. when 'raiseerror'
207** is true, raises any error; otherwise, return 0 in case of errors.
208*/
209int luaD_growstack (lua_State *L, int n, int raiseerror) {
210 int size = L->stacksize;
211 int newsize = 2 * size; /* tentative new size */
212 if (unlikely(size > LUAI_MAXSTACK)) { /* need more space after extra size? */
213 if (raiseerror)
214 luaD_throw(L, LUA_ERRERR); /* error inside message handler */
215 else return 0;
216 }
217 else {
218 int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
219 if (newsize > LUAI_MAXSTACK) /* cannot cross the limit */
220 newsize = LUAI_MAXSTACK;
221 if (newsize < needed) /* but must respect what was asked for */
222 newsize = needed;
223 if (unlikely(newsize > LUAI_MAXSTACK)) { /* stack overflow? */
224 /* add extra size to be able to handle the error message */
225 luaD_reallocstack(L, ERRORSTACKSIZE, raiseerror);
226 if (raiseerror)
227 luaG_runerror(L, "stack overflow");
228 else return 0;
229 }
230 } /* else no errors */
231 return luaD_reallocstack(L, newsize, raiseerror);
232}
233
234
235static int stackinuse (lua_State *L) {
236 CallInfo *ci;
237 StkId lim = L->top;
238 for (ci = L->ci; ci != NULL; ci = ci->previous) {
239 if (lim < ci->top) lim = ci->top;
240 }
241 lua_assert(lim <= L->stack_last);
242 return cast_int(lim - L->stack) + 1; /* part of stack in use */
243}
244
245
246void luaD_shrinkstack (lua_State *L) {
247 int inuse = stackinuse(L);
248 int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
249 if (goodsize > LUAI_MAXSTACK)
250 goodsize = LUAI_MAXSTACK; /* respect stack limit */
251 /* if thread is currently not handling a stack overflow and its
252 good size is smaller than current size, shrink its stack */
253 if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) &&
254 goodsize < L->stacksize)
255 luaD_reallocstack(L, goodsize, 0); /* ok if that fails */
256 else /* don't change stack */
257 condmovestack(L,{},{}); /* (change only for debugging) */
258 luaE_shrinkCI(L); /* shrink CI list */
259}
260
261
262void luaD_inctop (lua_State *L) {
263 luaD_checkstack(L, 1);
264 L->top++;
265}
266
267/* }================================================================== */
268
269
270/*
271** Call a hook for the given event. Make sure there is a hook to be
272** called. (Both 'L->hook' and 'L->hookmask', which trigger this
273** function, can be changed asynchronously by signals.)
274*/
275void luaD_hook (lua_State *L, int event, int line,
276 int ftransfer, int ntransfer) {
277 lua_Hook hook = L->hook;
278 if (hook && L->allowhook) { /* make sure there is a hook */
279 int mask = CIST_HOOKED;
280 CallInfo *ci = L->ci;
281 ptrdiff_t top = savestack(L, L->top);
282 ptrdiff_t ci_top = savestack(L, ci->top);
283 lua_Debug ar;
284 ar.event = event;
285 ar.currentline = line;
286 ar.i_ci = ci;
287 if (ntransfer != 0) {
288 mask |= CIST_TRAN; /* 'ci' has transfer information */
289 ci->u2.transferinfo.ftransfer = ftransfer;
290 ci->u2.transferinfo.ntransfer = ntransfer;
291 }
292 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
293 if (L->top + LUA_MINSTACK > ci->top)
294 ci->top = L->top + LUA_MINSTACK;
295 L->allowhook = 0; /* cannot call hooks inside a hook */
296 ci->callstatus |= mask;
297 lua_unlock(L);
298 (*hook)(L, &ar);
299 lua_lock(L);
300 lua_assert(!L->allowhook);
301 L->allowhook = 1;
302 ci->top = restorestack(L, ci_top);
303 L->top = restorestack(L, top);
304 ci->callstatus &= ~mask;
305 }
306}
307
308
309/*
310** Executes a call hook for Lua functions. This function is called
311** whenever 'hookmask' is not zero, so it checks whether call hooks are
312** active.
313*/
314void luaD_hookcall (lua_State *L, CallInfo *ci) {
315 int hook = (ci->callstatus & CIST_TAIL) ? LUA_HOOKTAILCALL : LUA_HOOKCALL;
316 Proto *p;
317 if (!(L->hookmask & LUA_MASKCALL)) /* some other hook? */
318 return; /* don't call hook */
319 p = clLvalue(s2v(ci->func))->p;
320 L->top = ci->top; /* prepare top */
321 ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */
322 luaD_hook(L, hook, -1, 1, p->numparams);
323 ci->u.l.savedpc--; /* correct 'pc' */
324}
325
326
327static StkId rethook (lua_State *L, CallInfo *ci, StkId firstres, int nres) {
328 ptrdiff_t oldtop = savestack(L, L->top); /* hook may change top */
329 int delta = 0;
330 if (isLuacode(ci)) {
331 Proto *p = clLvalue(s2v(ci->func))->p;
332 if (p->is_vararg)
333 delta = ci->u.l.nextraargs + p->numparams + 1;
334 if (L->top < ci->top)
335 L->top = ci->top; /* correct top to run hook */
336 }
337 if (L->hookmask & LUA_MASKRET) { /* is return hook on? */
338 int ftransfer;
339 ci->func += delta; /* if vararg, back to virtual 'func' */
340 ftransfer = cast(unsigned short, firstres - ci->func);
341 luaD_hook(L, LUA_HOOKRET, -1, ftransfer, nres); /* call it */
342 ci->func -= delta;
343 }
344 if (isLua(ci->previous))
345 L->oldpc = ci->previous->u.l.savedpc; /* update 'oldpc' */
346 return restorestack(L, oldtop);
347}
348
349
350/*
351** Check whether 'func' has a '__call' metafield. If so, put it in the
352** stack, below original 'func', so that 'luaD_call' can call it. Raise
353** an error if there is no '__call' metafield.
354*/
355void luaD_tryfuncTM (lua_State *L, StkId func) {
356 const TValue *tm = luaT_gettmbyobj(L, s2v(func), TM_CALL);
357 StkId p;
358 if (unlikely(ttisnil(tm)))
359 luaG_typeerror(L, s2v(func), "call"); /* nothing to call */
360 for (p = L->top; p > func; p--) /* open space for metamethod */
361 setobjs2s(L, p, p-1);
362 L->top++; /* stack space pre-allocated by the caller */
363 setobj2s(L, func, tm); /* metamethod is the new function to be called */
364}
365
366
367/*
368** Given 'nres' results at 'firstResult', move 'wanted' of them to 'res'.
369** Handle most typical cases (zero results for commands, one result for
370** expressions, multiple results for tail calls/single parameters)
371** separated.
372*/
373static void moveresults (lua_State *L, StkId res, int nres, int wanted) {
374 StkId firstresult;
375 int i;
376 switch (wanted) { /* handle typical cases separately */
377 case 0: /* no values needed */
378 L->top = res;
379 return;
380 case 1: /* one value needed */
381 if (nres == 0) /* no results? */
382 setnilvalue(s2v(res)); /* adjust with nil */
383 else
384 setobjs2s(L, res, L->top - nres); /* move it to proper place */
385 L->top = res + 1;
386 return;
387 case LUA_MULTRET:
388 wanted = nres; /* we want all results */
389 break;
390 default: /* multiple results (or to-be-closed variables) */
391 if (hastocloseCfunc(wanted)) { /* to-be-closed variables? */
392 ptrdiff_t savedres = savestack(L, res);
393 luaF_close(L, res, LUA_OK); /* may change the stack */
394 res = restorestack(L, savedres);
395 wanted = codeNresults(wanted); /* correct value */
396 if (wanted == LUA_MULTRET)
397 wanted = nres;
398 }
399 break;
400 }
401 firstresult = L->top - nres; /* index of first result */
402 /* move all results to correct place */
403 for (i = 0; i < nres && i < wanted; i++)
404 setobjs2s(L, res + i, firstresult + i);
405 for (; i < wanted; i++) /* complete wanted number of results */
406 setnilvalue(s2v(res + i));
407 L->top = res + wanted; /* top points after the last result */
408}
409
410
411/*
412** Finishes a function call: calls hook if necessary, removes CallInfo,
413** moves current number of results to proper place.
414*/
415void luaD_poscall (lua_State *L, CallInfo *ci, int nres) {
416 if (L->hookmask)
417 L->top = rethook(L, ci, L->top - nres, nres);
418 L->ci = ci->previous; /* back to caller */
419 /* move results to proper place */
420 moveresults(L, ci->func, nres, ci->nresults);
421}
422
423
424
425#define next_ci(L) (L->ci->next ? L->ci->next : luaE_extendCI(L))
426
427
428/*
429** Prepare a function for a tail call, building its call info on top
430** of the current call info. 'narg1' is the number of arguments plus 1
431** (so that it includes the function itself).
432*/
433void luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, int narg1) {
434 Proto *p = clLvalue(s2v(func))->p;
435 int fsize = p->maxstacksize; /* frame size */
436 int nfixparams = p->numparams;
437 int i;
438 for (i = 0; i < narg1; i++) /* move down function and arguments */
439 setobjs2s(L, ci->func + i, func + i);
440 checkstackGC(L, fsize);
441 func = ci->func; /* moved-down function */
442 for (; narg1 <= nfixparams; narg1++)
443 setnilvalue(s2v(func + narg1)); /* complete missing arguments */
444 ci->top = func + 1 + fsize; /* top for new function */
445 lua_assert(ci->top <= L->stack_last);
446 ci->u.l.savedpc = p->code; /* starting point */
447 ci->callstatus |= CIST_TAIL;
448 L->top = func + narg1; /* set top */
449}
450
451
452/*
453** Call a function (C or Lua). The function to be called is at *func.
454** The arguments are on the stack, right after the function.
455** When returns, all the results are on the stack, starting at the original
456** function position.
457*/
458void luaD_call (lua_State *L, StkId func, int nresults) {
459 lua_CFunction f;
460 retry:
461 switch (ttypetag(s2v(func))) {
462 case LUA_VCCL: /* C closure */
463 f = clCvalue(s2v(func))->f;
464 goto Cfunc;
465 case LUA_VLCF: /* light C function */
466 f = fvalue(s2v(func));
467 Cfunc: {
468 int n; /* number of returns */
469 CallInfo *ci = next_ci(L);
470 checkstackp(L, LUA_MINSTACK, func); /* ensure minimum stack size */
471 ci->nresults = nresults;
472 ci->callstatus = CIST_C;
473 ci->top = L->top + LUA_MINSTACK;
474 ci->func = func;
475 L->ci = ci;
476 lua_assert(ci->top <= L->stack_last);
477 if (L->hookmask & LUA_MASKCALL) {
478 int narg = cast_int(L->top - func) - 1;
479 luaD_hook(L, LUA_HOOKCALL, -1, 1, narg);
480 }
481 lua_unlock(L);
482 n = (*f)(L); /* do the actual call */
483 lua_lock(L);
484 api_checknelems(L, n);
485 luaD_poscall(L, ci, n);
486 break;
487 }
488 case LUA_VLCL: { /* Lua function */
489 CallInfo *ci = next_ci(L);
490 Proto *p = clLvalue(s2v(func))->p;
491 int narg = cast_int(L->top - func) - 1; /* number of real arguments */
492 int nfixparams = p->numparams;
493 int fsize = p->maxstacksize; /* frame size */
494 checkstackp(L, fsize, func);
495 ci->nresults = nresults;
496 ci->u.l.savedpc = p->code; /* starting point */
497 ci->callstatus = 0;
498 ci->top = func + 1 + fsize;
499 ci->func = func;
500 L->ci = ci;
501 for (; narg < nfixparams; narg++)
502 setnilvalue(s2v(L->top++)); /* complete missing arguments */
503 lua_assert(ci->top <= L->stack_last);
504 luaV_execute(L, ci); /* run the function */
505 break;
506 }
507 default: { /* not a function */
508 checkstackp(L, 1, func); /* space for metamethod */
509 luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */
510 goto retry; /* try again with metamethod */
511 }
512 }
513}
514
515
516/*
517** Similar to 'luaD_call', but does not allow yields during the call.
518** If there is a stack overflow, freeing all CI structures will
519** force the subsequent call to invoke 'luaE_extendCI', which then
520** will raise any errors.
521*/
522void luaD_callnoyield (lua_State *L, StkId func, int nResults) {
523 incXCcalls(L);
524 if (getCcalls(L) <= CSTACKERR) /* possible stack overflow? */
525 luaE_freeCI(L);
526 luaD_call(L, func, nResults);
527 decXCcalls(L);
528}
529
530
531/*
532** Completes the execution of an interrupted C function, calling its
533** continuation function.
534*/
535static void finishCcall (lua_State *L, int status) {
536 CallInfo *ci = L->ci;
537 int n;
538 /* must have a continuation and must be able to call it */
539 lua_assert(ci->u.c.k != NULL && yieldable(L));
540 /* error status can only happen in a protected call */
541 lua_assert((ci->callstatus & CIST_YPCALL) || status == LUA_YIELD);
542 if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */
543 ci->callstatus &= ~CIST_YPCALL; /* continuation is also inside it */
544 L->errfunc = ci->u.c.old_errfunc; /* with the same error function */
545 }
546 /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already
547 handled */
548 adjustresults(L, ci->nresults);
549 lua_unlock(L);
550 n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation function */
551 lua_lock(L);
552 api_checknelems(L, n);
553 luaD_poscall(L, ci, n); /* finish 'luaD_call' */
554}
555
556
557/*
558** Executes "full continuation" (everything in the stack) of a
559** previously interrupted coroutine until the stack is empty (or another
560** interruption long-jumps out of the loop). If the coroutine is
561** recovering from an error, 'ud' points to the error status, which must
562** be passed to the first continuation function (otherwise the default
563** status is LUA_YIELD).
564*/
565static void unroll (lua_State *L, void *ud) {
566 CallInfo *ci;
567 if (ud != NULL) /* error status? */
568 finishCcall(L, *(int *)ud); /* finish 'lua_pcallk' callee */
569 while ((ci = L->ci) != &L->base_ci) { /* something in the stack */
570 if (!isLua(ci)) /* C function? */
571 finishCcall(L, LUA_YIELD); /* complete its execution */
572 else { /* Lua function */
573 luaV_finishOp(L); /* finish interrupted instruction */
574 luaV_execute(L, ci); /* execute down to higher C 'boundary' */
575 }
576 }
577}
578
579
580/*
581** Try to find a suspended protected call (a "recover point") for the
582** given thread.
583*/
584static CallInfo *findpcall (lua_State *L) {
585 CallInfo *ci;
586 for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */
587 if (ci->callstatus & CIST_YPCALL)
588 return ci;
589 }
590 return NULL; /* no pending pcall */
591}
592
593
594/*
595** Recovers from an error in a coroutine. Finds a recover point (if
596** there is one) and completes the execution of the interrupted
597** 'luaD_pcall'. If there is no recover point, returns zero.
598*/
599static int recover (lua_State *L, int status) {
600 StkId oldtop;
601 CallInfo *ci = findpcall(L);
602 if (ci == NULL) return 0; /* no recovery point */
603 /* "finish" luaD_pcall */
604 oldtop = restorestack(L, ci->u2.funcidx);
605 luaF_close(L, oldtop, status); /* may change the stack */
606 oldtop = restorestack(L, ci->u2.funcidx);
607 luaD_seterrorobj(L, status, oldtop);
608 L->ci = ci;
609 L->allowhook = getoah(ci->callstatus); /* restore original 'allowhook' */
610 luaD_shrinkstack(L);
611 L->errfunc = ci->u.c.old_errfunc;
612 return 1; /* continue running the coroutine */
613}
614
615
616/*
617** Signal an error in the call to 'lua_resume', not in the execution
618** of the coroutine itself. (Such errors should not be handled by any
619** coroutine error handler and should not kill the coroutine.)
620*/
621static int resume_error (lua_State *L, const char *msg, int narg) {
622 L->top -= narg; /* remove args from the stack */
623 setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */
624 api_incr_top(L);
625 lua_unlock(L);
626 return LUA_ERRRUN;
627}
628
629
630/*
631** Do the work for 'lua_resume' in protected mode. Most of the work
632** depends on the status of the coroutine: initial state, suspended
633** inside a hook, or regularly suspended (optionally with a continuation
634** function), plus erroneous cases: non-suspended coroutine or dead
635** coroutine.
636*/
637static void resume (lua_State *L, void *ud) {
638 int n = *(cast(int*, ud)); /* number of arguments */
639 StkId firstArg = L->top - n; /* first argument */
640 CallInfo *ci = L->ci;
641 if (L->status == LUA_OK) { /* starting a coroutine? */
642 luaD_call(L, firstArg - 1, LUA_MULTRET);
643 }
644 else { /* resuming from previous yield */
645 lua_assert(L->status == LUA_YIELD);
646 L->status = LUA_OK; /* mark that it is running (again) */
647 if (isLua(ci)) /* yielded inside a hook? */
648 luaV_execute(L, ci); /* just continue running Lua code */
649 else { /* 'common' yield */
650 if (ci->u.c.k != NULL) { /* does it have a continuation function? */
651 lua_unlock(L);
652 n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */
653 lua_lock(L);
654 api_checknelems(L, n);
655 }
656 luaD_poscall(L, ci, n); /* finish 'luaD_call' */
657 }
658 unroll(L, NULL); /* run continuation */
659 }
660}
661
662LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs,
663 int *nresults) {
664 int status;
665 lua_lock(L);
666 if (L->status == LUA_OK) { /* may be starting a coroutine */
667 if (L->ci != &L->base_ci) /* not in base level? */
668 return resume_error(L, "cannot resume non-suspended coroutine", nargs);
669 else if (L->top - (L->ci->func + 1) == nargs) /* no function? */
670 return resume_error(L, "cannot resume dead coroutine", nargs);
671 }
672 else if (L->status != LUA_YIELD) /* ended with errors? */
673 return resume_error(L, "cannot resume dead coroutine", nargs);
674 if (from == NULL)
675 L->nCcalls = CSTACKTHREAD;
676 else /* correct 'nCcalls' for this thread */
677 L->nCcalls = getCcalls(from) + from->nci - L->nci - CSTACKCF;
678 if (L->nCcalls <= CSTACKERR)
679 return resume_error(L, "C stack overflow", nargs);
680 luai_userstateresume(L, nargs);
681 api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
682 status = luaD_rawrunprotected(L, resume, &nargs);
683 /* continue running after recoverable errors */
684 while (errorstatus(status) && recover(L, status)) {
685 /* unroll continuation */
686 status = luaD_rawrunprotected(L, unroll, &status);
687 }
688 if (likely(!errorstatus(status)))
689 lua_assert(status == L->status); /* normal end or yield */
690 else { /* unrecoverable error */
691 L->status = cast_byte(status); /* mark thread as 'dead' */
692 luaD_seterrorobj(L, status, L->top); /* push error message */
693 L->ci->top = L->top;
694 }
695 *nresults = (status == LUA_YIELD) ? L->ci->u2.nyield
696 : cast_int(L->top - (L->ci->func + 1));
697 lua_unlock(L);
698 return status;
699}
700
701
702LUA_API int lua_isyieldable (lua_State *L) {
703 return yieldable(L);
704}
705
706
707LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx,
708 lua_KFunction k) {
709 CallInfo *ci = L->ci;
710 luai_userstateyield(L, nresults);
711 lua_lock(L);
712 api_checknelems(L, nresults);
713 if (unlikely(!yieldable(L))) {
714 if (L != G(L)->mainthread)
715 luaG_runerror(L, "attempt to yield across a C-call boundary");
716 else
717 luaG_runerror(L, "attempt to yield from outside a coroutine");
718 }
719 L->status = LUA_YIELD;
720 if (isLua(ci)) { /* inside a hook? */
721 lua_assert(!isLuacode(ci));
722 api_check(L, k == NULL, "hooks cannot continue after yielding");
723 ci->u2.nyield = 0; /* no results */
724 }
725 else {
726 if ((ci->u.c.k = k) != NULL) /* is there a continuation? */
727 ci->u.c.ctx = ctx; /* save context */
728 ci->u2.nyield = nresults; /* save number of results */
729 luaD_throw(L, LUA_YIELD);
730 }
731 lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */
732 lua_unlock(L);
733 return 0; /* return to 'luaD_hook' */
734}
735
736
737/*
738** Call the C function 'func' in protected mode, restoring basic
739** thread information ('allowhook', etc.) and in particular
740** its stack level in case of errors.
741*/
742int luaD_pcall (lua_State *L, Pfunc func, void *u,
743 ptrdiff_t old_top, ptrdiff_t ef) {
744 int status;
745 CallInfo *old_ci = L->ci;
746 lu_byte old_allowhooks = L->allowhook;
747 ptrdiff_t old_errfunc = L->errfunc;
748 L->errfunc = ef;
749 status = luaD_rawrunprotected(L, func, u);
750 if (unlikely(status != LUA_OK)) { /* an error occurred? */
751 StkId oldtop = restorestack(L, old_top);
752 L->ci = old_ci;
753 L->allowhook = old_allowhooks;
754 status = luaF_close(L, oldtop, status);
755 oldtop = restorestack(L, old_top); /* previous call may change stack */
756 luaD_seterrorobj(L, status, oldtop);
757 luaD_shrinkstack(L);
758 }
759 L->errfunc = old_errfunc;
760 return status;
761}
762
763
764
765/*
766** Execute a protected parser.
767*/
768struct SParser { /* data to 'f_parser' */
769 ZIO *z;
770 Mbuffer buff; /* dynamic structure used by the scanner */
771 Dyndata dyd; /* dynamic structures used by the parser */
772 const char *mode;
773 const char *name;
774};
775
776
777static void checkmode (lua_State *L, const char *mode, const char *x) {
778 if (mode && strchr(mode, x[0]) == NULL) {
779 luaO_pushfstring(L,
780 "attempt to load a %s chunk (mode is '%s')", x, mode);
781 luaD_throw(L, LUA_ERRSYNTAX);
782 }
783}
784
785
786static void f_parser (lua_State *L, void *ud) {
787 LClosure *cl;
788 struct SParser *p = cast(struct SParser *, ud);
789 int c = zgetc(p->z); /* read first character */
790 if (c == LUA_SIGNATURE[0]) {
791 checkmode(L, p->mode, "binary");
792 cl = luaU_undump(L, p->z, p->name);
793 }
794 else {
795 checkmode(L, p->mode, "text");
796 cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
797 }
798 lua_assert(cl->nupvalues == cl->p->sizeupvalues);
799 luaF_initupvals(L, cl);
800}
801
802
803int luaD_protectedparser (lua_State *L, ZIO *z, const char *name,
804 const char *mode) {
805 struct SParser p;
806 int status;
807 incnny(L); /* cannot yield during parsing */
808 p.z = z; p.name = name; p.mode = mode;
809 p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0;
810 p.dyd.gt.arr = NULL; p.dyd.gt.size = 0;
811 p.dyd.label.arr = NULL; p.dyd.label.size = 0;
812 luaZ_initbuffer(L, &p.buff);
813 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
814 luaZ_freebuffer(L, &p.buff);
815 luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size);
816 luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size);
817 luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size);
818 decnny(L);
819 return status;
820}
821
822