diff options
Diffstat (limited to 'source/luametatex/source/luacore/lua54/src/ldo.c')
| -rw-r--r-- | source/luametatex/source/luacore/lua54/src/ldo.c | 1005 |
1 files changed, 1005 insertions, 0 deletions
diff --git a/source/luametatex/source/luacore/lua54/src/ldo.c b/source/luametatex/source/luacore/lua54/src/ldo.c new file mode 100644 index 000000000..419b3db93 --- /dev/null +++ b/source/luametatex/source/luacore/lua54/src/ldo.c @@ -0,0 +1,1005 @@ +/* +** $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 LUA_OK: { /* special case only for closing upvalues */ + setnilvalue(s2v(oldtop)); /* no error message */ + break; + } + default: { + lua_assert(errorstatus(errcode)); /* real error */ + 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 = luaE_resetthread(L, errcode); /* close all upvalues */ + 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? */ + 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) { + l_uint32 oldnCcalls = L->nCcalls; + 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 = oldnCcalls; + return lj.status; +} + +/* }====================================================== */ + + +/* +** {================================================================== +** Stack reallocation +** =================================================================== +*/ +static void correctstack (lua_State *L, StkId oldstack, StkId newstack) { + CallInfo *ci; + UpVal *up; + L->top = (L->top - oldstack) + newstack; + L->tbclist = (L->tbclist - 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) + + +/* +** Reallocate the stack to a new size, correcting all pointers into +** it. (There are pointers to a stack from its upvalues, from its list +** of call infos, plus a few individual pointers.) The reallocation is +** done in two steps (allocation + free) because the correction must be +** done while both addresses (the old stack and the new one) are valid. +** (In ISO C, any pointer use after the pointer has been deallocated is +** undefined behavior.) +** In case of allocation error, raise an error or return false according +** to 'raiseerror'. +*/ +int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) { + int oldsize = stacksize(L); + int i; + StkId newstack = luaM_reallocvector(L, NULL, 0, + newsize + EXTRA_STACK, StackValue); + lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); + if (l_unlikely(newstack == NULL)) { /* reallocation failed? */ + if (raiseerror) + luaM_error(L); + else return 0; /* do not raise an error */ + } + /* number of elements to be copied to the new stack */ + i = ((oldsize <= newsize) ? oldsize : newsize) + EXTRA_STACK; + memcpy(newstack, L->stack, i * sizeof(StackValue)); + for (; i < newsize + EXTRA_STACK; i++) + setnilvalue(s2v(newstack + i)); /* erase new segment */ + correctstack(L, L->stack, newstack); + luaM_freearray(L, L->stack, oldsize + EXTRA_STACK); + L->stack = newstack; + L->stack_last = L->stack + newsize; + 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 = stacksize(L); + if (l_unlikely(size > LUAI_MAXSTACK)) { + /* if stack is larger than maximum, thread is already using the + extra space reserved for errors, that is, thread is handling + a stack error; cannot grow further than that. */ + lua_assert(stacksize(L) == ERRORSTACKSIZE); + if (raiseerror) + luaD_throw(L, LUA_ERRERR); /* error inside message handler */ + return 0; /* if not 'raiseerror', just signal it */ + } + else if (n < LUAI_MAXSTACK) { /* avoids arithmetic overflows */ + int newsize = 2 * size; /* tentative new size */ + int needed = cast_int(L->top - L->stack) + n; + if (newsize > LUAI_MAXSTACK) /* cannot cross the limit */ + newsize = LUAI_MAXSTACK; + if (newsize < needed) /* but must respect what was asked for */ + newsize = needed; + if (l_likely(newsize <= LUAI_MAXSTACK)) + return luaD_reallocstack(L, newsize, raiseerror); + } + /* else 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"); + return 0; +} + + +/* +** Compute how much of the stack is being used, by computing the +** maximum top of all call frames in the stack and the current top. +*/ +static int stackinuse (lua_State *L) { + CallInfo *ci; + int res; + 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 + EXTRA_STACK); + res = cast_int(lim - L->stack) + 1; /* part of stack in use */ + if (res < LUA_MINSTACK) + res = LUA_MINSTACK; /* ensure a minimum size */ + return res; +} + + +/* +** If stack size is more than 3 times the current use, reduce that size +** to twice the current use. (So, the final stack size is at most 2/3 the +** previous size, and half of its entries are empty.) +** As a particular case, if stack was handling a stack overflow and now +** it is not, 'max' (limited by LUAI_MAXSTACK) will be smaller than +** stacksize (equal to ERRORSTACKSIZE in this case), and so the stack +** will be reduced to a "regular" size. +*/ +void luaD_shrinkstack (lua_State *L) { + int inuse = stackinuse(L); + int nsize = inuse * 2; /* proposed new size */ + int max = inuse * 3; /* maximum "reasonable" size */ + if (max > LUAI_MAXSTACK) { + max = LUAI_MAXSTACK; /* respect stack limit */ + if (nsize > LUAI_MAXSTACK) + nsize = LUAI_MAXSTACK; + } + /* if thread is currently not handling a stack overflow and its + size is larger than maximum "reasonable" size, shrink it */ + if (inuse <= LUAI_MAXSTACK && stacksize(L) > max) + luaD_reallocstack(L, nsize, 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); /* preserve original 'top' */ + ptrdiff_t ci_top = savestack(L, ci->top); /* idem for '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; + } + if (isLua(ci) && L->top < ci->top) + L->top = ci->top; /* protect entire activation register */ + luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ + if (ci->top < L->top + LUA_MINSTACK) + 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) { + L->oldpc = 0; /* set 'oldpc' for new function */ + if (L->hookmask & LUA_MASKCALL) { /* is call hook on? */ + int event = (ci->callstatus & CIST_TAIL) ? LUA_HOOKTAILCALL + : LUA_HOOKCALL; + Proto *p = ci_func(ci)->p; + ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ + luaD_hook(L, event, -1, 1, p->numparams); + ci->u.l.savedpc--; /* correct 'pc' */ + } +} + + +/* +** Executes a return hook for Lua and C functions and sets/corrects +** 'oldpc'. (Note that this correction is needed by the line hook, so it +** is done even when return hooks are off.) +*/ +static void rethook (lua_State *L, CallInfo *ci, int nres) { + if (L->hookmask & LUA_MASKRET) { /* is return hook on? */ + StkId firstres = L->top - nres; /* index of first result */ + int delta = 0; /* correction for vararg functions */ + int ftransfer; + if (isLua(ci)) { + Proto *p = ci_func(ci)->p; + if (p->is_vararg) + delta = ci->u.l.nextraargs + p->numparams + 1; + } + 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 = ci->previous)) + L->oldpc = pcRel(ci->u.l.savedpc, ci_func(ci)->p); /* set 'oldpc' */ +} + + +/* +** Check whether 'func' has a '__call' metafield. If so, put it in the +** stack, below original 'func', so that 'luaD_precall' can call it. Raise +** an error if there is no '__call' metafield. +*/ +StkId luaD_tryfuncTM (lua_State *L, StkId func) { + const TValue *tm; + StkId p; + checkstackGCp(L, 1, func); /* space for metamethod */ + tm = luaT_gettmbyobj(L, s2v(func), TM_CALL); /* (after previous GC) */ + if (l_unlikely(ttisnil(tm))) + luaG_callerror(L, s2v(func)); /* 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 */ + return func; +} + + +/* +** 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. +*/ +l_sinline 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 /* at least one result */ + 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: /* two/more results and/or to-be-closed variables */ + if (hastocloseCfunc(wanted)) { /* to-be-closed variables? */ + L->ci->callstatus |= CIST_CLSRET; /* in case of yields */ + L->ci->u2.nres = nres; + res = luaF_close(L, res, CLOSEKTOP, 1); + L->ci->callstatus &= ~CIST_CLSRET; + if (L->hookmask) { /* if needed, call hook after '__close's */ + ptrdiff_t savedres = savestack(L, res); + rethook(L, L->ci, nres); + res = restorestack(L, savedres); /* hook can move stack */ + } + wanted = decodeNresults(wanted); + if (wanted == LUA_MULTRET) + wanted = nres; /* we want all results */ + } + break; + } + /* generic case */ + firstresult = L->top - nres; /* index of first result */ + if (nres > wanted) /* extra results? */ + nres = wanted; /* don't need them */ + for (i = 0; i < nres; i++) /* move all results to correct place */ + 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, moves current +** number of results to proper place, and returns to previous call +** info. If function has to close variables, hook must be called after +** that. +*/ +void luaD_poscall (lua_State *L, CallInfo *ci, int nres) { + int wanted = ci->nresults; + if (l_unlikely(L->hookmask && !hastocloseCfunc(wanted))) + rethook(L, ci, nres); + /* move results to proper place */ + moveresults(L, ci->func, nres, wanted); + /* function cannot be in any of these cases when returning */ + lua_assert(!(ci->callstatus & + (CIST_HOOKED | CIST_YPCALL | CIST_FIN | CIST_TRAN | CIST_CLSRET))); + L->ci = ci->previous; /* back to caller (after closing variables) */ +} + + + +#define next_ci(L) (L->ci->next ? L->ci->next : luaE_extendCI(L)) + + +l_sinline CallInfo *prepCallInfo (lua_State *L, StkId func, int nret, + int mask, StkId top) { + CallInfo *ci = L->ci = next_ci(L); /* new frame */ + ci->func = func; + ci->nresults = nret; + ci->callstatus = mask; + ci->top = top; + return ci; +} + + +/* +** precall for C functions +*/ +l_sinline int precallC (lua_State *L, StkId func, int nresults, + lua_CFunction f) { + int n; /* number of returns */ + CallInfo *ci; + checkstackGCp(L, LUA_MINSTACK, func); /* ensure minimum stack size */ + L->ci = ci = prepCallInfo(L, func, nresults, CIST_C, + L->top + LUA_MINSTACK); + lua_assert(ci->top <= L->stack_last); + if (l_unlikely(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); + return n; +} + + +/* +** 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). Return the number of +** results, if it was a C function, or -1 for a Lua function. +*/ +int luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, + int narg1, int delta) { + retry: + switch (ttypetag(s2v(func))) { + case LUA_VCCL: /* C closure */ + return precallC(L, func, LUA_MULTRET, clCvalue(s2v(func))->f); + case LUA_VLCF: /* light C function */ + return precallC(L, func, LUA_MULTRET, fvalue(s2v(func))); + case LUA_VLCL: { /* Lua function */ + Proto *p = clLvalue(s2v(func))->p; + int fsize = p->maxstacksize; /* frame size */ + int nfixparams = p->numparams; + int i; + checkstackGCp(L, fsize - delta, func); + ci->func -= delta; /* restore 'func' (if vararg) */ + for (i = 0; i < narg1; i++) /* move down function and arguments */ + setobjs2s(L, ci->func + i, func + i); + 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 */ + return -1; + } + default: { /* not a function */ + func = luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */ + /* return luaD_pretailcall(L, ci, func, narg1 + 1, delta); */ + narg1++; + goto retry; /* try again */ + } + } +} + + +/* +** Prepares the call to a function (C or Lua). For C functions, also do +** the call. The function to be called is at '*func'. The arguments +** are on the stack, right after the function. Returns the CallInfo +** to be executed, if it was a Lua function. Otherwise (a C function) +** returns NULL, with all the results on the stack, starting at the +** original function position. +*/ +CallInfo *luaD_precall (lua_State *L, StkId func, int nresults) { + retry: + switch (ttypetag(s2v(func))) { + case LUA_VCCL: /* C closure */ + precallC(L, func, nresults, clCvalue(s2v(func))->f); + return NULL; + case LUA_VLCF: /* light C function */ + precallC(L, func, nresults, fvalue(s2v(func))); + return NULL; + case LUA_VLCL: { /* Lua function */ + CallInfo *ci; + 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 */ + checkstackGCp(L, fsize, func); + L->ci = ci = prepCallInfo(L, func, nresults, 0, func + 1 + fsize); + ci->u.l.savedpc = p->code; /* starting point */ + for (; narg < nfixparams; narg++) + setnilvalue(s2v(L->top++)); /* complete missing arguments */ + lua_assert(ci->top <= L->stack_last); + return ci; + } + default: { /* not a function */ + func = luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */ + /* return luaD_precall(L, func, nresults); */ + goto retry; /* try again with metamethod */ + } + } +} + + +/* +** Call a function (C or Lua) through C. 'inc' can be 1 (increment +** number of recursive invocations in the C stack) or nyci (the same +** plus increment number of non-yieldable calls). +** This function can be called with some use of EXTRA_STACK, so it should +** check the stack before doing anything else. 'luaD_precall' already +** does that. +*/ +l_sinline void ccall (lua_State *L, StkId func, int nResults, int inc) { + CallInfo *ci; + L->nCcalls += inc; + if (l_unlikely(getCcalls(L) >= LUAI_MAXCCALLS)) { + checkstackp(L, 0, func); /* free any use of EXTRA_STACK */ + luaE_checkcstack(L); + } + if ((ci = luaD_precall(L, func, nResults)) != NULL) { /* Lua function? */ + ci->callstatus = CIST_FRESH; /* mark that it is a "fresh" execute */ + luaV_execute(L, ci); /* call it */ + } + L->nCcalls -= inc; +} + + +/* +** External interface for 'ccall' +*/ +void luaD_call (lua_State *L, StkId func, int nResults) { + ccall(L, func, nResults, 1); +} + + +/* +** Similar to 'luaD_call', but does not allow yields during the call. +*/ +void luaD_callnoyield (lua_State *L, StkId func, int nResults) { + ccall(L, func, nResults, nyci); +} + + +/* +** Finish the job of 'lua_pcallk' after it was interrupted by an yield. +** (The caller, 'finishCcall', does the final call to 'adjustresults'.) +** The main job is to complete the 'luaD_pcall' called by 'lua_pcallk'. +** If a '__close' method yields here, eventually control will be back +** to 'finishCcall' (when that '__close' method finally returns) and +** 'finishpcallk' will run again and close any still pending '__close' +** methods. Similarly, if a '__close' method errs, 'precover' calls +** 'unroll' which calls ''finishCcall' and we are back here again, to +** close any pending '__close' methods. +** Note that, up to the call to 'luaF_close', the corresponding +** 'CallInfo' is not modified, so that this repeated run works like the +** first one (except that it has at least one less '__close' to do). In +** particular, field CIST_RECST preserves the error status across these +** multiple runs, changing only if there is a new error. +*/ +static int finishpcallk (lua_State *L, CallInfo *ci) { + int status = getcistrecst(ci); /* get original status */ + if (l_likely(status == LUA_OK)) /* no error? */ + status = LUA_YIELD; /* was interrupted by an yield */ + else { /* error */ + StkId func = restorestack(L, ci->u2.funcidx); + L->allowhook = getoah(ci->callstatus); /* restore 'allowhook' */ + func = luaF_close(L, func, status, 1); /* can yield or raise an error */ + luaD_seterrorobj(L, status, func); + luaD_shrinkstack(L); /* restore stack size in case of overflow */ + setcistrecst(ci, LUA_OK); /* clear original status */ + } + ci->callstatus &= ~CIST_YPCALL; + L->errfunc = ci->u.c.old_errfunc; + /* if it is here, there were errors or yields; unlike 'lua_pcallk', + do not change status */ + return status; +} + + +/* +** Completes the execution of a C function interrupted by an yield. +** The interruption must have happened while the function was either +** closing its tbc variables in 'moveresults' or executing +** 'lua_callk'/'lua_pcallk'. In the first case, it just redoes +** 'luaD_poscall'. In the second case, the call to 'finishpcallk' +** finishes the interrupted execution of 'lua_pcallk'. After that, it +** calls the continuation of the interrupted function and finally it +** completes the job of the 'luaD_call' that called the function. In +** the call to 'adjustresults', we do not know the number of results +** of the function called by 'lua_callk'/'lua_pcallk', so we are +** conservative and use LUA_MULTRET (always adjust). +*/ +static void finishCcall (lua_State *L, CallInfo *ci) { + int n; /* actual number of results from C function */ + if (ci->callstatus & CIST_CLSRET) { /* was returning? */ + lua_assert(hastocloseCfunc(ci->nresults)); + n = ci->u2.nres; /* just redo 'luaD_poscall' */ + /* don't need to reset CIST_CLSRET, as it will be set again anyway */ + } + else { + int status = LUA_YIELD; /* default if there were no errors */ + /* must have a continuation and must be able to call it */ + lua_assert(ci->u.c.k != NULL && yieldable(L)); + if (ci->callstatus & CIST_YPCALL) /* was inside a 'lua_pcallk'? */ + status = finishpcallk(L, ci); /* finish it */ + adjustresults(L, LUA_MULTRET); /* finish 'lua_callk' */ + lua_unlock(L); + n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation */ + 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). +*/ +static void unroll (lua_State *L, void *ud) { + CallInfo *ci; + UNUSED(ud); + while ((ci = L->ci) != &L->base_ci) { /* something in the stack */ + if (!isLua(ci)) /* C function? */ + finishCcall(L, ci); /* 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 */ +} + + +/* +** 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? */ + ccall(L, firstArg - 1, LUA_MULTRET, 0); /* just call its body */ + 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? */ + L->top = firstArg; /* discard arguments */ + 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 */ + } +} + + +/* +** Unrolls a coroutine in protected mode while there are recoverable +** errors, that is, errors inside a protected call. (Any error +** interrupts 'unroll', and this loop protects it again so it can +** continue.) Stops with a normal end (status == LUA_OK), an yield +** (status == LUA_YIELD), or an unprotected error ('findpcall' doesn't +** find a recover point). +*/ +static int precover (lua_State *L, int status) { + CallInfo *ci; + while (errorstatus(status) && (ci = findpcall(L)) != NULL) { + L->ci = ci; /* go down to recovery functions */ + setcistrecst(ci, status); /* status to finish 'pcall' */ + status = luaD_rawrunprotected(L, unroll, NULL); + } + return status; +} + + +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); + L->nCcalls = (from) ? getCcalls(from) : 0; + if (getCcalls(L) >= LUAI_MAXCCALLS) + return resume_error(L, "C stack overflow", nargs); + L->nCcalls++; + 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 */ + status = precover(L, status); + if (l_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; + luai_userstateyield(L, nresults); + lua_lock(L); + ci = L->ci; + api_checknelems(L, nresults); + if (l_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; + ci->u2.nyield = nresults; /* save number of results */ + if (isLua(ci)) { /* inside a hook? */ + lua_assert(!isLuacode(ci)); + api_check(L, nresults == 0, "hooks cannot yield values"); + api_check(L, k == NULL, "hooks cannot continue after yielding"); + } + else { + if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ + ci->u.c.ctx = ctx; /* save context */ + 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' */ +} + + +/* +** Auxiliary structure to call 'luaF_close' in protected mode. +*/ +struct CloseP { + StkId level; + int status; +}; + + +/* +** Auxiliary function to call 'luaF_close' in protected mode. +*/ +static void closepaux (lua_State *L, void *ud) { + struct CloseP *pcl = cast(struct CloseP *, ud); + luaF_close(L, pcl->level, pcl->status, 0); +} + + +/* +** Calls 'luaF_close' in protected mode. Return the original status +** or, in case of errors, the new status. +*/ +int luaD_closeprotected (lua_State *L, ptrdiff_t level, int status) { + CallInfo *old_ci = L->ci; + lu_byte old_allowhooks = L->allowhook; + for (;;) { /* keep closing upvalues until no more errors */ + struct CloseP pcl; + pcl.level = restorestack(L, level); pcl.status = status; + status = luaD_rawrunprotected(L, &closepaux, &pcl); + if (l_likely(status == LUA_OK)) /* no more errors? */ + return pcl.status; + else { /* an error occurred; restore saved state and repeat */ + L->ci = old_ci; + L->allowhook = old_allowhooks; + } + } +} + + +/* +** 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 (l_unlikely(status != LUA_OK)) { /* an error occurred? */ + L->ci = old_ci; + L->allowhook = old_allowhooks; + status = luaD_closeprotected(L, old_top, status); + luaD_seterrorobj(L, status, restorestack(L, old_top)); + luaD_shrinkstack(L); /* restore stack size in case of overflow */ + } + 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; +} + + |