diff options
Diffstat (limited to 'test/external/lua-5.4.0/src/ldo.c')
| -rw-r--r-- | test/external/lua-5.4.0/src/ldo.c | 822 |
1 files changed, 822 insertions, 0 deletions
diff --git a/test/external/lua-5.4.0/src/ldo.c b/test/external/lua-5.4.0/src/ldo.c new file mode 100644 index 0000000..c563b1d --- /dev/null +++ b/test/external/lua-5.4.0/src/ldo.c @@ -0,0 +1,822 @@ +/* +** $Id: ldo.c $ +** Stack and Call structure of Lua +** See Copyright Notice in lua.h +*/ + +#define ldo_c +#define LUA_CORE + +#include "lprefix.h" + + +#include <setjmp.h> +#include <stdlib.h> +#include <string.h> + +#include "lua.h" + +#include "lapi.h" +#include "ldebug.h" +#include "ldo.h" +#include "lfunc.h" +#include "lgc.h" +#include "lmem.h" +#include "lobject.h" +#include "lopcodes.h" +#include "lparser.h" +#include "lstate.h" +#include "lstring.h" +#include "ltable.h" +#include "ltm.h" +#include "lundump.h" +#include "lvm.h" +#include "lzio.h" + + + +#define errorstatus(s) ((s) > LUA_YIELD) + + +/* +** {====================================================== +** Error-recovery functions +** ======================================================= +*/ + +/* +** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By +** default, Lua handles errors with exceptions when compiling as +** C++ code, with _longjmp/_setjmp when asked to use them, and with +** longjmp/setjmp otherwise. +*/ +#if !defined(LUAI_THROW) /* { */ + +#if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) /* { */ + +/* C++ exceptions */ +#define LUAI_THROW(L,c) throw(c) +#define LUAI_TRY(L,c,a) \ + try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; } +#define luai_jmpbuf int /* dummy variable */ + +#elif defined(LUA_USE_POSIX) /* }{ */ + +/* in POSIX, try _longjmp/_setjmp (more efficient) */ +#define LUAI_THROW(L,c) _longjmp((c)->b, 1) +#define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a } +#define luai_jmpbuf jmp_buf + +#else /* }{ */ + +/* ISO C handling with long jumps */ +#define LUAI_THROW(L,c) longjmp((c)->b, 1) +#define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } +#define luai_jmpbuf jmp_buf + +#endif /* } */ + +#endif /* } */ + + + +/* chain list of long jump buffers */ +struct lua_longjmp { + struct lua_longjmp *previous; + luai_jmpbuf b; + volatile int status; /* error code */ +}; + + +void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) { + switch (errcode) { + case LUA_ERRMEM: { /* memory error? */ + setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */ + break; + } + case LUA_ERRERR: { + setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); + break; + } + case CLOSEPROTECT: { + setnilvalue(s2v(oldtop)); /* no error message */ + break; + } + default: { + setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ + break; + } + } + L->top = oldtop + 1; +} + + +l_noret luaD_throw (lua_State *L, int errcode) { + if (L->errorJmp) { /* thread has an error handler? */ + L->errorJmp->status = errcode; /* set status */ + LUAI_THROW(L, L->errorJmp); /* jump to it */ + } + else { /* thread has no error handler */ + global_State *g = G(L); + errcode = luaF_close(L, L->stack, errcode); /* close all upvalues */ + L->status = cast_byte(errcode); /* mark it as dead */ + if (g->mainthread->errorJmp) { /* main thread has a handler? */ + setobjs2s(L, g->mainthread->top++, L->top - 1); /* copy error obj. */ + luaD_throw(g->mainthread, errcode); /* re-throw in main thread */ + } + else { /* no handler at all; abort */ + if (g->panic) { /* panic function? */ + luaD_seterrorobj(L, errcode, L->top); /* assume EXTRA_STACK */ + if (L->ci->top < L->top) + L->ci->top = L->top; /* pushing msg. can break this invariant */ + lua_unlock(L); + g->panic(L); /* call panic function (last chance to jump out) */ + } + abort(); + } + } +} + + +int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { + global_State *g = G(L); + l_uint32 oldnCcalls = g->Cstacklimit - (L->nCcalls + L->nci); + struct lua_longjmp lj; + lj.status = LUA_OK; + lj.previous = L->errorJmp; /* chain new error handler */ + L->errorJmp = &lj; + LUAI_TRY(L, &lj, + (*f)(L, ud); + ); + L->errorJmp = lj.previous; /* restore old error handler */ + L->nCcalls = g->Cstacklimit - oldnCcalls - L->nci; + return lj.status; +} + +/* }====================================================== */ + + +/* +** {================================================================== +** Stack reallocation +** =================================================================== +*/ +static void correctstack (lua_State *L, StkId oldstack, StkId newstack) { + CallInfo *ci; + UpVal *up; + if (oldstack == newstack) + return; /* stack address did not change */ + L->top = (L->top - oldstack) + newstack; + for (up = L->openupval; up != NULL; up = up->u.open.next) + up->v = s2v((uplevel(up) - oldstack) + newstack); + for (ci = L->ci; ci != NULL; ci = ci->previous) { + ci->top = (ci->top - oldstack) + newstack; + ci->func = (ci->func - oldstack) + newstack; + if (isLua(ci)) + ci->u.l.trap = 1; /* signal to update 'trap' in 'luaV_execute' */ + } +} + + +/* some space for error handling */ +#define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) + + +int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) { + int lim = L->stacksize; + StkId newstack = luaM_reallocvector(L, L->stack, lim, newsize, StackValue); + lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); + lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); + if (unlikely(newstack == NULL)) { /* reallocation failed? */ + if (raiseerror) + luaM_error(L); + else return 0; /* do not raise an error */ + } + for (; lim < newsize; lim++) + setnilvalue(s2v(newstack + lim)); /* erase new segment */ + correctstack(L, L->stack, newstack); + L->stack = newstack; + L->stacksize = newsize; + L->stack_last = L->stack + newsize - EXTRA_STACK; + return 1; +} + + +/* +** Try to grow the stack by at least 'n' elements. when 'raiseerror' +** is true, raises any error; otherwise, return 0 in case of errors. +*/ +int luaD_growstack (lua_State *L, int n, int raiseerror) { + int size = L->stacksize; + int newsize = 2 * size; /* tentative new size */ + if (unlikely(size > LUAI_MAXSTACK)) { /* need more space after extra size? */ + if (raiseerror) + luaD_throw(L, LUA_ERRERR); /* error inside message handler */ + else return 0; + } + else { + int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; + if (newsize > LUAI_MAXSTACK) /* cannot cross the limit */ + newsize = LUAI_MAXSTACK; + if (newsize < needed) /* but must respect what was asked for */ + newsize = needed; + if (unlikely(newsize > LUAI_MAXSTACK)) { /* stack overflow? */ + /* add extra size to be able to handle the error message */ + luaD_reallocstack(L, ERRORSTACKSIZE, raiseerror); + if (raiseerror) + luaG_runerror(L, "stack overflow"); + else return 0; + } + } /* else no errors */ + return luaD_reallocstack(L, newsize, raiseerror); +} + + +static int stackinuse (lua_State *L) { + CallInfo *ci; + StkId lim = L->top; + for (ci = L->ci; ci != NULL; ci = ci->previous) { + if (lim < ci->top) lim = ci->top; + } + lua_assert(lim <= L->stack_last); + return cast_int(lim - L->stack) + 1; /* part of stack in use */ +} + + +void luaD_shrinkstack (lua_State *L) { + int inuse = stackinuse(L); + int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; + if (goodsize > LUAI_MAXSTACK) + goodsize = LUAI_MAXSTACK; /* respect stack limit */ + /* if thread is currently not handling a stack overflow and its + good size is smaller than current size, shrink its stack */ + if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) && + goodsize < L->stacksize) + luaD_reallocstack(L, goodsize, 0); /* ok if that fails */ + else /* don't change stack */ + condmovestack(L,{},{}); /* (change only for debugging) */ + luaE_shrinkCI(L); /* shrink CI list */ +} + + +void luaD_inctop (lua_State *L) { + luaD_checkstack(L, 1); + L->top++; +} + +/* }================================================================== */ + + +/* +** Call a hook for the given event. Make sure there is a hook to be +** called. (Both 'L->hook' and 'L->hookmask', which trigger this +** function, can be changed asynchronously by signals.) +*/ +void luaD_hook (lua_State *L, int event, int line, + int ftransfer, int ntransfer) { + lua_Hook hook = L->hook; + if (hook && L->allowhook) { /* make sure there is a hook */ + int mask = CIST_HOOKED; + CallInfo *ci = L->ci; + ptrdiff_t top = savestack(L, L->top); + ptrdiff_t ci_top = savestack(L, ci->top); + lua_Debug ar; + ar.event = event; + ar.currentline = line; + ar.i_ci = ci; + if (ntransfer != 0) { + mask |= CIST_TRAN; /* 'ci' has transfer information */ + ci->u2.transferinfo.ftransfer = ftransfer; + ci->u2.transferinfo.ntransfer = ntransfer; + } + luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ + if (L->top + LUA_MINSTACK > ci->top) + ci->top = L->top + LUA_MINSTACK; + L->allowhook = 0; /* cannot call hooks inside a hook */ + ci->callstatus |= mask; + lua_unlock(L); + (*hook)(L, &ar); + lua_lock(L); + lua_assert(!L->allowhook); + L->allowhook = 1; + ci->top = restorestack(L, ci_top); + L->top = restorestack(L, top); + ci->callstatus &= ~mask; + } +} + + +/* +** Executes a call hook for Lua functions. This function is called +** whenever 'hookmask' is not zero, so it checks whether call hooks are +** active. +*/ +void luaD_hookcall (lua_State *L, CallInfo *ci) { + int hook = (ci->callstatus & CIST_TAIL) ? LUA_HOOKTAILCALL : LUA_HOOKCALL; + Proto *p; + if (!(L->hookmask & LUA_MASKCALL)) /* some other hook? */ + return; /* don't call hook */ + p = clLvalue(s2v(ci->func))->p; + L->top = ci->top; /* prepare top */ + ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ + luaD_hook(L, hook, -1, 1, p->numparams); + ci->u.l.savedpc--; /* correct 'pc' */ +} + + +static StkId rethook (lua_State *L, CallInfo *ci, StkId firstres, int nres) { + ptrdiff_t oldtop = savestack(L, L->top); /* hook may change top */ + int delta = 0; + if (isLuacode(ci)) { + Proto *p = clLvalue(s2v(ci->func))->p; + if (p->is_vararg) + delta = ci->u.l.nextraargs + p->numparams + 1; + if (L->top < ci->top) + L->top = ci->top; /* correct top to run hook */ + } + if (L->hookmask & LUA_MASKRET) { /* is return hook on? */ + int ftransfer; + ci->func += delta; /* if vararg, back to virtual 'func' */ + ftransfer = cast(unsigned short, firstres - ci->func); + luaD_hook(L, LUA_HOOKRET, -1, ftransfer, nres); /* call it */ + ci->func -= delta; + } + if (isLua(ci->previous)) + L->oldpc = ci->previous->u.l.savedpc; /* update 'oldpc' */ + return restorestack(L, oldtop); +} + + +/* +** Check whether 'func' has a '__call' metafield. If so, put it in the +** stack, below original 'func', so that 'luaD_call' can call it. Raise +** an error if there is no '__call' metafield. +*/ +void luaD_tryfuncTM (lua_State *L, StkId func) { + const TValue *tm = luaT_gettmbyobj(L, s2v(func), TM_CALL); + StkId p; + if (unlikely(ttisnil(tm))) + luaG_typeerror(L, s2v(func), "call"); /* nothing to call */ + for (p = L->top; p > func; p--) /* open space for metamethod */ + setobjs2s(L, p, p-1); + L->top++; /* stack space pre-allocated by the caller */ + setobj2s(L, func, tm); /* metamethod is the new function to be called */ +} + + +/* +** Given 'nres' results at 'firstResult', move 'wanted' of them to 'res'. +** Handle most typical cases (zero results for commands, one result for +** expressions, multiple results for tail calls/single parameters) +** separated. +*/ +static void moveresults (lua_State *L, StkId res, int nres, int wanted) { + StkId firstresult; + int i; + switch (wanted) { /* handle typical cases separately */ + case 0: /* no values needed */ + L->top = res; + return; + case 1: /* one value needed */ + if (nres == 0) /* no results? */ + setnilvalue(s2v(res)); /* adjust with nil */ + else + setobjs2s(L, res, L->top - nres); /* move it to proper place */ + L->top = res + 1; + return; + case LUA_MULTRET: + wanted = nres; /* we want all results */ + break; + default: /* multiple results (or to-be-closed variables) */ + if (hastocloseCfunc(wanted)) { /* to-be-closed variables? */ + ptrdiff_t savedres = savestack(L, res); + luaF_close(L, res, LUA_OK); /* may change the stack */ + res = restorestack(L, savedres); + wanted = codeNresults(wanted); /* correct value */ + if (wanted == LUA_MULTRET) + wanted = nres; + } + break; + } + firstresult = L->top - nres; /* index of first result */ + /* move all results to correct place */ + for (i = 0; i < nres && i < wanted; i++) + setobjs2s(L, res + i, firstresult + i); + for (; i < wanted; i++) /* complete wanted number of results */ + setnilvalue(s2v(res + i)); + L->top = res + wanted; /* top points after the last result */ +} + + +/* +** Finishes a function call: calls hook if necessary, removes CallInfo, +** moves current number of results to proper place. +*/ +void luaD_poscall (lua_State *L, CallInfo *ci, int nres) { + if (L->hookmask) + L->top = rethook(L, ci, L->top - nres, nres); + L->ci = ci->previous; /* back to caller */ + /* move results to proper place */ + moveresults(L, ci->func, nres, ci->nresults); +} + + + +#define next_ci(L) (L->ci->next ? L->ci->next : luaE_extendCI(L)) + + +/* +** Prepare a function for a tail call, building its call info on top +** of the current call info. 'narg1' is the number of arguments plus 1 +** (so that it includes the function itself). +*/ +void luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, int narg1) { + Proto *p = clLvalue(s2v(func))->p; + int fsize = p->maxstacksize; /* frame size */ + int nfixparams = p->numparams; + int i; + for (i = 0; i < narg1; i++) /* move down function and arguments */ + setobjs2s(L, ci->func + i, func + i); + checkstackGC(L, fsize); + func = ci->func; /* moved-down function */ + for (; narg1 <= nfixparams; narg1++) + setnilvalue(s2v(func + narg1)); /* complete missing arguments */ + ci->top = func + 1 + fsize; /* top for new function */ + lua_assert(ci->top <= L->stack_last); + ci->u.l.savedpc = p->code; /* starting point */ + ci->callstatus |= CIST_TAIL; + L->top = func + narg1; /* set top */ +} + + +/* +** Call a function (C or Lua). The function to be called is at *func. +** The arguments are on the stack, right after the function. +** When returns, all the results are on the stack, starting at the original +** function position. +*/ +void luaD_call (lua_State *L, StkId func, int nresults) { + lua_CFunction f; + retry: + switch (ttypetag(s2v(func))) { + case LUA_VCCL: /* C closure */ + f = clCvalue(s2v(func))->f; + goto Cfunc; + case LUA_VLCF: /* light C function */ + f = fvalue(s2v(func)); + Cfunc: { + int n; /* number of returns */ + CallInfo *ci = next_ci(L); + checkstackp(L, LUA_MINSTACK, func); /* ensure minimum stack size */ + ci->nresults = nresults; + ci->callstatus = CIST_C; + ci->top = L->top + LUA_MINSTACK; + ci->func = func; + L->ci = ci; + lua_assert(ci->top <= L->stack_last); + if (L->hookmask & LUA_MASKCALL) { + int narg = cast_int(L->top - func) - 1; + luaD_hook(L, LUA_HOOKCALL, -1, 1, narg); + } + lua_unlock(L); + n = (*f)(L); /* do the actual call */ + lua_lock(L); + api_checknelems(L, n); + luaD_poscall(L, ci, n); + break; + } + case LUA_VLCL: { /* Lua function */ + CallInfo *ci = next_ci(L); + Proto *p = clLvalue(s2v(func))->p; + int narg = cast_int(L->top - func) - 1; /* number of real arguments */ + int nfixparams = p->numparams; + int fsize = p->maxstacksize; /* frame size */ + checkstackp(L, fsize, func); + ci->nresults = nresults; + ci->u.l.savedpc = p->code; /* starting point */ + ci->callstatus = 0; + ci->top = func + 1 + fsize; + ci->func = func; + L->ci = ci; + for (; narg < nfixparams; narg++) + setnilvalue(s2v(L->top++)); /* complete missing arguments */ + lua_assert(ci->top <= L->stack_last); + luaV_execute(L, ci); /* run the function */ + break; + } + default: { /* not a function */ + checkstackp(L, 1, func); /* space for metamethod */ + luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */ + goto retry; /* try again with metamethod */ + } + } +} + + +/* +** Similar to 'luaD_call', but does not allow yields during the call. +** If there is a stack overflow, freeing all CI structures will +** force the subsequent call to invoke 'luaE_extendCI', which then +** will raise any errors. +*/ +void luaD_callnoyield (lua_State *L, StkId func, int nResults) { + incXCcalls(L); + if (getCcalls(L) <= CSTACKERR) /* possible stack overflow? */ + luaE_freeCI(L); + luaD_call(L, func, nResults); + decXCcalls(L); +} + + +/* +** Completes the execution of an interrupted C function, calling its +** continuation function. +*/ +static void finishCcall (lua_State *L, int status) { + CallInfo *ci = L->ci; + int n; + /* must have a continuation and must be able to call it */ + lua_assert(ci->u.c.k != NULL && yieldable(L)); + /* error status can only happen in a protected call */ + lua_assert((ci->callstatus & CIST_YPCALL) || status == LUA_YIELD); + if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ + ci->callstatus &= ~CIST_YPCALL; /* continuation is also inside it */ + L->errfunc = ci->u.c.old_errfunc; /* with the same error function */ + } + /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already + handled */ + adjustresults(L, ci->nresults); + lua_unlock(L); + n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation function */ + lua_lock(L); + api_checknelems(L, n); + luaD_poscall(L, ci, n); /* finish 'luaD_call' */ +} + + +/* +** Executes "full continuation" (everything in the stack) of a +** previously interrupted coroutine until the stack is empty (or another +** interruption long-jumps out of the loop). If the coroutine is +** recovering from an error, 'ud' points to the error status, which must +** be passed to the first continuation function (otherwise the default +** status is LUA_YIELD). +*/ +static void unroll (lua_State *L, void *ud) { + CallInfo *ci; + if (ud != NULL) /* error status? */ + finishCcall(L, *(int *)ud); /* finish 'lua_pcallk' callee */ + while ((ci = L->ci) != &L->base_ci) { /* something in the stack */ + if (!isLua(ci)) /* C function? */ + finishCcall(L, LUA_YIELD); /* complete its execution */ + else { /* Lua function */ + luaV_finishOp(L); /* finish interrupted instruction */ + luaV_execute(L, ci); /* execute down to higher C 'boundary' */ + } + } +} + + +/* +** Try to find a suspended protected call (a "recover point") for the +** given thread. +*/ +static CallInfo *findpcall (lua_State *L) { + CallInfo *ci; + for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ + if (ci->callstatus & CIST_YPCALL) + return ci; + } + return NULL; /* no pending pcall */ +} + + +/* +** Recovers from an error in a coroutine. Finds a recover point (if +** there is one) and completes the execution of the interrupted +** 'luaD_pcall'. If there is no recover point, returns zero. +*/ +static int recover (lua_State *L, int status) { + StkId oldtop; + CallInfo *ci = findpcall(L); + if (ci == NULL) return 0; /* no recovery point */ + /* "finish" luaD_pcall */ + oldtop = restorestack(L, ci->u2.funcidx); + luaF_close(L, oldtop, status); /* may change the stack */ + oldtop = restorestack(L, ci->u2.funcidx); + luaD_seterrorobj(L, status, oldtop); + L->ci = ci; + L->allowhook = getoah(ci->callstatus); /* restore original 'allowhook' */ + luaD_shrinkstack(L); + L->errfunc = ci->u.c.old_errfunc; + return 1; /* continue running the coroutine */ +} + + +/* +** Signal an error in the call to 'lua_resume', not in the execution +** of the coroutine itself. (Such errors should not be handled by any +** coroutine error handler and should not kill the coroutine.) +*/ +static int resume_error (lua_State *L, const char *msg, int narg) { + L->top -= narg; /* remove args from the stack */ + setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ + api_incr_top(L); + lua_unlock(L); + return LUA_ERRRUN; +} + + +/* +** Do the work for 'lua_resume' in protected mode. Most of the work +** depends on the status of the coroutine: initial state, suspended +** inside a hook, or regularly suspended (optionally with a continuation +** function), plus erroneous cases: non-suspended coroutine or dead +** coroutine. +*/ +static void resume (lua_State *L, void *ud) { + int n = *(cast(int*, ud)); /* number of arguments */ + StkId firstArg = L->top - n; /* first argument */ + CallInfo *ci = L->ci; + if (L->status == LUA_OK) { /* starting a coroutine? */ + luaD_call(L, firstArg - 1, LUA_MULTRET); + } + else { /* resuming from previous yield */ + lua_assert(L->status == LUA_YIELD); + L->status = LUA_OK; /* mark that it is running (again) */ + if (isLua(ci)) /* yielded inside a hook? */ + luaV_execute(L, ci); /* just continue running Lua code */ + else { /* 'common' yield */ + if (ci->u.c.k != NULL) { /* does it have a continuation function? */ + lua_unlock(L); + n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */ + lua_lock(L); + api_checknelems(L, n); + } + luaD_poscall(L, ci, n); /* finish 'luaD_call' */ + } + unroll(L, NULL); /* run continuation */ + } +} + +LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs, + int *nresults) { + int status; + lua_lock(L); + if (L->status == LUA_OK) { /* may be starting a coroutine */ + if (L->ci != &L->base_ci) /* not in base level? */ + return resume_error(L, "cannot resume non-suspended coroutine", nargs); + else if (L->top - (L->ci->func + 1) == nargs) /* no function? */ + return resume_error(L, "cannot resume dead coroutine", nargs); + } + else if (L->status != LUA_YIELD) /* ended with errors? */ + return resume_error(L, "cannot resume dead coroutine", nargs); + if (from == NULL) + L->nCcalls = CSTACKTHREAD; + else /* correct 'nCcalls' for this thread */ + L->nCcalls = getCcalls(from) + from->nci - L->nci - CSTACKCF; + if (L->nCcalls <= CSTACKERR) + return resume_error(L, "C stack overflow", nargs); + luai_userstateresume(L, nargs); + api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); + status = luaD_rawrunprotected(L, resume, &nargs); + /* continue running after recoverable errors */ + while (errorstatus(status) && recover(L, status)) { + /* unroll continuation */ + status = luaD_rawrunprotected(L, unroll, &status); + } + if (likely(!errorstatus(status))) + lua_assert(status == L->status); /* normal end or yield */ + else { /* unrecoverable error */ + L->status = cast_byte(status); /* mark thread as 'dead' */ + luaD_seterrorobj(L, status, L->top); /* push error message */ + L->ci->top = L->top; + } + *nresults = (status == LUA_YIELD) ? L->ci->u2.nyield + : cast_int(L->top - (L->ci->func + 1)); + lua_unlock(L); + return status; +} + + +LUA_API int lua_isyieldable (lua_State *L) { + return yieldable(L); +} + + +LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx, + lua_KFunction k) { + CallInfo *ci = L->ci; + luai_userstateyield(L, nresults); + lua_lock(L); + api_checknelems(L, nresults); + if (unlikely(!yieldable(L))) { + if (L != G(L)->mainthread) + luaG_runerror(L, "attempt to yield across a C-call boundary"); + else + luaG_runerror(L, "attempt to yield from outside a coroutine"); + } + L->status = LUA_YIELD; + if (isLua(ci)) { /* inside a hook? */ + lua_assert(!isLuacode(ci)); + api_check(L, k == NULL, "hooks cannot continue after yielding"); + ci->u2.nyield = 0; /* no results */ + } + else { + if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ + ci->u.c.ctx = ctx; /* save context */ + ci->u2.nyield = nresults; /* save number of results */ + luaD_throw(L, LUA_YIELD); + } + lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ + lua_unlock(L); + return 0; /* return to 'luaD_hook' */ +} + + +/* +** Call the C function 'func' in protected mode, restoring basic +** thread information ('allowhook', etc.) and in particular +** its stack level in case of errors. +*/ +int luaD_pcall (lua_State *L, Pfunc func, void *u, + ptrdiff_t old_top, ptrdiff_t ef) { + int status; + CallInfo *old_ci = L->ci; + lu_byte old_allowhooks = L->allowhook; + ptrdiff_t old_errfunc = L->errfunc; + L->errfunc = ef; + status = luaD_rawrunprotected(L, func, u); + if (unlikely(status != LUA_OK)) { /* an error occurred? */ + StkId oldtop = restorestack(L, old_top); + L->ci = old_ci; + L->allowhook = old_allowhooks; + status = luaF_close(L, oldtop, status); + oldtop = restorestack(L, old_top); /* previous call may change stack */ + luaD_seterrorobj(L, status, oldtop); + luaD_shrinkstack(L); + } + L->errfunc = old_errfunc; + return status; +} + + + +/* +** Execute a protected parser. +*/ +struct SParser { /* data to 'f_parser' */ + ZIO *z; + Mbuffer buff; /* dynamic structure used by the scanner */ + Dyndata dyd; /* dynamic structures used by the parser */ + const char *mode; + const char *name; +}; + + +static void checkmode (lua_State *L, const char *mode, const char *x) { + if (mode && strchr(mode, x[0]) == NULL) { + luaO_pushfstring(L, + "attempt to load a %s chunk (mode is '%s')", x, mode); + luaD_throw(L, LUA_ERRSYNTAX); + } +} + + +static void f_parser (lua_State *L, void *ud) { + LClosure *cl; + struct SParser *p = cast(struct SParser *, ud); + int c = zgetc(p->z); /* read first character */ + if (c == LUA_SIGNATURE[0]) { + checkmode(L, p->mode, "binary"); + cl = luaU_undump(L, p->z, p->name); + } + else { + checkmode(L, p->mode, "text"); + cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); + } + lua_assert(cl->nupvalues == cl->p->sizeupvalues); + luaF_initupvals(L, cl); +} + + +int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, + const char *mode) { + struct SParser p; + int status; + incnny(L); /* cannot yield during parsing */ + p.z = z; p.name = name; p.mode = mode; + p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; + p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; + p.dyd.label.arr = NULL; p.dyd.label.size = 0; + luaZ_initbuffer(L, &p.buff); + status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); + luaZ_freebuffer(L, &p.buff); + luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); + luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); + luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); + decnny(L); + return status; +} + + |