/*** $Id: ldo.c,v 2.135 2014/11/11 17:13:39 roberto Exp $** 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 */}; static void 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; } 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); 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? */ 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) { unsigned short 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;} /* }====================================================== */ static void correctstack (lua_State *L, TValue *oldstack) { CallInfo *ci; UpVal *up; L->top = (L->top - oldstack) + L->stack; for (up = L->openupval; up != NULL; up = up->u.open.next) up->v = (up->v - oldstack) + L->stack; for (ci = L->ci; ci != NULL; ci = ci->previous) { ci->top = (ci->top - oldstack) + L->stack; ci->func = (ci->func - oldstack) + L->stack; if (isLua(ci)) ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; }} /* some space for error handling */#define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) void luaD_reallocstack (lua_State *L, int newsize) { TValue *oldstack = L->stack; int lim = L->stacksize; lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); for (; lim < newsize; lim++) setnilvalue(L->stack + lim); /* erase new segment */ L->stacksize = newsize; L->stack_last = L->stack + newsize - EXTRA_STACK; correctstack(L, oldstack);} void luaD_growstack (lua_State *L, int n) { int size = L->stacksize; if (size > LUAI_MAXSTACK) /* error after extra size? */ luaD_throw(L, LUA_ERRERR); else { int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; int newsize = 2 * size; if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; if (newsize < needed) newsize = needed; if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ luaD_reallocstack(L, ERRORSTACKSIZE); luaG_runerror(L, "stack overflow"); } else luaD_reallocstack(L, newsize); }} static int stackinuse (lua_State *L) { CallInfo *ci; StkId lim = L->top; for (ci = L->ci; ci != NULL; ci = ci->previous) { lua_assert(ci->top <= L->stack_last); if (lim < ci->top) lim = ci->top; } 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; if (L->stacksize > LUAI_MAXSTACK) /* was handling stack overflow? */ luaE_freeCI(L); /* free all CIs (list grew because of an error) */ else luaE_shrinkCI(L); /* shrink list */ if (inuse > LUAI_MAXSTACK || /* still handling stack overflow? */ goodsize >= L->stacksize) /* would grow instead of shrink? */ condmovestack(L); /* don't change stack (change only for debugging) */ else luaD_reallocstack(L, goodsize); /* shrink it */} void luaD_hook (lua_State *L, int event, int line) { lua_Hook hook = L->hook; if (hook && L->allowhook) { 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; luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); L->allowhook = 0; /* cannot call hooks inside a hook */ ci->callstatus |= CIST_HOOKED; 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 &= ~CIST_HOOKED; }} static void callhook (lua_State *L, CallInfo *ci) { int hook = LUA_HOOKCALL; ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ if (isLua(ci->previous) && GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { ci->callstatus |= CIST_TAIL; hook = LUA_HOOKTAILCALL; } luaD_hook(L, hook, -1); ci->u.l.savedpc--; /* correct 'pc' */} static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { int i; int nfixargs = p->numparams; StkId base, fixed; lua_assert(actual >= nfixargs); /* move fixed parameters to final position */ luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ fixed = L->top - actual; /* first fixed argument */ base = L->top; /* final position of first argument */ for (i=0; i<nfixargs; i++) { setobjs2s(L, L->top++, fixed + i); setnilvalue(fixed + i); } return base;} /*** Check whether __call metafield of 'func' is a function. If so, put** it in stack below original 'func' so that 'luaD_precall' can call** it. Raise an error if __call metafield is not a function.*/static void tryfuncTM (lua_State *L, StkId func) { const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); StkId p; if (!ttisfunction(tm)) luaG_typeerror(L, func, "call"); /* Open a hole inside the stack at 'func' */ for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); L->top++; /* slot ensured by caller */ setobj2s(L, func, tm); /* tag method is the new function to be called */} #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) /*** returns true if function has been executed (C function)*/int luaD_precall (lua_State *L, StkId func, int nresults) { lua_CFunction f; CallInfo *ci; int n; /* number of arguments (Lua) or returns (C) */ ptrdiff_t funcr = savestack(L, func); switch (ttype(func)) { case LUA_TLCF: /* light C function */ f = fvalue(func); goto Cfunc; case LUA_TCCL: { /* C closure */ f = clCvalue(func)->f; Cfunc: luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = restorestack(L, funcr); ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); ci->callstatus = 0; luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) luaD_hook(L, LUA_HOOKCALL, -1); lua_unlock(L); n = (*f)(L); /* do the actual call */ lua_lock(L); api_checknelems(L, n); luaD_poscall(L, L->top - n); return 1; } case LUA_TLCL: { /* Lua function: prepare its call */ StkId base; Proto *p = clLvalue(func)->p; n = cast_int(L->top - func) - 1; /* number of real arguments */ luaD_checkstack(L, p->maxstacksize); for (; n < p->numparams; n++) setnilvalue(L->top++); /* complete missing arguments */ if (!p->is_vararg) { func = restorestack(L, funcr); base = func + 1; } else { base = adjust_varargs(L, p, n); func = restorestack(L, funcr); /* previous call can change stack */ } ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = func; ci->u.l.base = base; ci->top = base + p->maxstacksize; lua_assert(ci->top <= L->stack_last); ci->u.l.savedpc = p->code; /* starting point */ ci->callstatus = CIST_LUA; L->top = ci->top; luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) callhook(L, ci); return 0; } default: { /* not a function */ luaD_checkstack(L, 1); /* ensure space for metamethod */ func = restorestack(L, funcr); /* previous call may change stack */ tryfuncTM(L, func); /* try to get '__call' metamethod */ return luaD_precall(L, func, nresults); /* now it must be a function */ } }} int luaD_poscall (lua_State *L, StkId firstResult) { StkId res; int wanted, i; CallInfo *ci = L->ci; if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { if (L->hookmask & LUA_MASKRET) { ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ luaD_hook(L, LUA_HOOKRET, -1); firstResult = restorestack(L, fr); } L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ } res = ci->func; /* res == final position of 1st result */ wanted = ci->nresults; L->ci = ci = ci->previous; /* back to caller */ /* move results to correct place */ for (i = wanted; i != 0 && firstResult < L->top; i--) setobjs2s(L, res++, firstResult++); while (i-- > 0) setnilvalue(res++); L->top = res; return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */} /*** 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, int allowyield) { if (++L->nCcalls >= LUAI_MAXCCALLS) { if (L->nCcalls == LUAI_MAXCCALLS) luaG_runerror(L, "C stack overflow"); else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ } if (!allowyield) L->nny++; if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ luaV_execute(L); /* call it */ if (!allowyield) L->nny--; L->nCcalls--;} /*** 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 && L->nny == 0); /* 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; /* finish 'lua_pcall' */ L->errfunc = ci->u.c.old_errfunc; } /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already handled */ adjustresults(L, ci->nresults); /* call continuation function */ lua_unlock(L); n = (*ci->u.c.k)(L, status, ci->u.c.ctx); lua_lock(L); api_checknelems(L, n); /* finish 'luaD_precall' */ luaD_poscall(L, L->top - n);} /*** 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) { if (ud != NULL) /* error status? */ finishCcall(L, *(int *)ud); /* finish 'lua_pcallk' callee */ while (L->ci != &L->base_ci) { /* something in the stack */ if (!isLua(L->ci)) /* C function? */ finishCcall(L, LUA_YIELD); /* complete its execution */ else { /* Lua function */ luaV_finishOp(L); /* finish interrupted instruction */ luaV_execute(L); /* 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 */Lines 1–500 of 717. Load more
/* ** $Id: ldo.c,v 2.135 2014/11/11 17:13:39 roberto Exp $ ** 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 */ }; static void 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; } 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); 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? */ 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) { unsigned short 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; } /* }====================================================== */ static void correctstack (lua_State *L, TValue *oldstack) { CallInfo *ci; UpVal *up; L->top = (L->top - oldstack) + L->stack; for (up = L->openupval; up != NULL; up = up->u.open.next) up->v = (up->v - oldstack) + L->stack; for (ci = L->ci; ci != NULL; ci = ci->previous) { ci->top = (ci->top - oldstack) + L->stack; ci->func = (ci->func - oldstack) + L->stack; if (isLua(ci)) ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; } } /* some space for error handling */ #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) void luaD_reallocstack (lua_State *L, int newsize) { TValue *oldstack = L->stack; int lim = L->stacksize; lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); for (; lim < newsize; lim++) setnilvalue(L->stack + lim); /* erase new segment */ L->stacksize = newsize; L->stack_last = L->stack + newsize - EXTRA_STACK; correctstack(L, oldstack); } void luaD_growstack (lua_State *L, int n) { int size = L->stacksize; if (size > LUAI_MAXSTACK) /* error after extra size? */ luaD_throw(L, LUA_ERRERR); else { int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; int newsize = 2 * size; if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; if (newsize < needed) newsize = needed; if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ luaD_reallocstack(L, ERRORSTACKSIZE); luaG_runerror(L, "stack overflow"); } else luaD_reallocstack(L, newsize); } } static int stackinuse (lua_State *L) { CallInfo *ci; StkId lim = L->top; for (ci = L->ci; ci != NULL; ci = ci->previous) { lua_assert(ci->top <= L->stack_last); if (lim < ci->top) lim = ci->top; } 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; if (L->stacksize > LUAI_MAXSTACK) /* was handling stack overflow? */ luaE_freeCI(L); /* free all CIs (list grew because of an error) */ else luaE_shrinkCI(L); /* shrink list */ if (inuse > LUAI_MAXSTACK || /* still handling stack overflow? */ goodsize >= L->stacksize) /* would grow instead of shrink? */ condmovestack(L); /* don't change stack (change only for debugging) */ else luaD_reallocstack(L, goodsize); /* shrink it */ } void luaD_hook (lua_State *L, int event, int line) { lua_Hook hook = L->hook; if (hook && L->allowhook) { 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; luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); L->allowhook = 0; /* cannot call hooks inside a hook */ ci->callstatus |= CIST_HOOKED; 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 &= ~CIST_HOOKED; } } static void callhook (lua_State *L, CallInfo *ci) { int hook = LUA_HOOKCALL; ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ if (isLua(ci->previous) && GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { ci->callstatus |= CIST_TAIL; hook = LUA_HOOKTAILCALL; } luaD_hook(L, hook, -1); ci->u.l.savedpc--; /* correct 'pc' */ } static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { int i; int nfixargs = p->numparams; StkId base, fixed; lua_assert(actual >= nfixargs); /* move fixed parameters to final position */ luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ fixed = L->top - actual; /* first fixed argument */ base = L->top; /* final position of first argument */ for (i=0; i<nfixargs; i++) { setobjs2s(L, L->top++, fixed + i); setnilvalue(fixed + i); } return base; } /* ** Check whether __call metafield of 'func' is a function. If so, put ** it in stack below original 'func' so that 'luaD_precall' can call ** it. Raise an error if __call metafield is not a function. */ static void tryfuncTM (lua_State *L, StkId func) { const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); StkId p; if (!ttisfunction(tm)) luaG_typeerror(L, func, "call"); /* Open a hole inside the stack at 'func' */ for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); L->top++; /* slot ensured by caller */ setobj2s(L, func, tm); /* tag method is the new function to be called */ } #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) /* ** returns true if function has been executed (C function) */ int luaD_precall (lua_State *L, StkId func, int nresults) { lua_CFunction f; CallInfo *ci; int n; /* number of arguments (Lua) or returns (C) */ ptrdiff_t funcr = savestack(L, func); switch (ttype(func)) { case LUA_TLCF: /* light C function */ f = fvalue(func); goto Cfunc; case LUA_TCCL: { /* C closure */ f = clCvalue(func)->f; Cfunc: luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = restorestack(L, funcr); ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); ci->callstatus = 0; luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) luaD_hook(L, LUA_HOOKCALL, -1); lua_unlock(L); n = (*f)(L); /* do the actual call */ lua_lock(L); api_checknelems(L, n); luaD_poscall(L, L->top - n); return 1; } case LUA_TLCL: { /* Lua function: prepare its call */ StkId base; Proto *p = clLvalue(func)->p; n = cast_int(L->top - func) - 1; /* number of real arguments */ luaD_checkstack(L, p->maxstacksize); for (; n < p->numparams; n++) setnilvalue(L->top++); /* complete missing arguments */ if (!p->is_vararg) { func = restorestack(L, funcr); base = func + 1; } else { base = adjust_varargs(L, p, n); func = restorestack(L, funcr); /* previous call can change stack */ } ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = func; ci->u.l.base = base; ci->top = base + p->maxstacksize; lua_assert(ci->top <= L->stack_last); ci->u.l.savedpc = p->code; /* starting point */ ci->callstatus = CIST_LUA; L->top = ci->top; luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) callhook(L, ci); return 0; } default: { /* not a function */ luaD_checkstack(L, 1); /* ensure space for metamethod */ func = restorestack(L, funcr); /* previous call may change stack */ tryfuncTM(L, func); /* try to get '__call' metamethod */ return luaD_precall(L, func, nresults); /* now it must be a function */ } } } int luaD_poscall (lua_State *L, StkId firstResult) { StkId res; int wanted, i; CallInfo *ci = L->ci; if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { if (L->hookmask & LUA_MASKRET) { ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ luaD_hook(L, LUA_HOOKRET, -1); firstResult = restorestack(L, fr); } L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ } res = ci->func; /* res == final position of 1st result */ wanted = ci->nresults; L->ci = ci = ci->previous; /* back to caller */ /* move results to correct place */ for (i = wanted; i != 0 && firstResult < L->top; i--) setobjs2s(L, res++, firstResult++); while (i-- > 0) setnilvalue(res++); L->top = res; return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ } /* ** 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, int allowyield) { if (++L->nCcalls >= LUAI_MAXCCALLS) { if (L->nCcalls == LUAI_MAXCCALLS) luaG_runerror(L, "C stack overflow"); else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ } if (!allowyield) L->nny++; if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ luaV_execute(L); /* call it */ if (!allowyield) L->nny--; L->nCcalls--; } /* ** 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 && L->nny == 0); /* 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; /* finish 'lua_pcall' */ L->errfunc = ci->u.c.old_errfunc; } /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already handled */ adjustresults(L, ci->nresults); /* call continuation function */ lua_unlock(L); n = (*ci->u.c.k)(L, status, ci->u.c.ctx); lua_lock(L); api_checknelems(L, n); /* finish 'luaD_precall' */ luaD_poscall(L, L->top - n); } /* ** 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) { if (ud != NULL) /* error status? */ finishCcall(L, *(int *)ud); /* finish 'lua_pcallk' callee */ while (L->ci != &L->base_ci) { /* something in the stack */ if (!isLua(L->ci)) /* C function? */ finishCcall(L, LUA_YIELD); /* complete its execution */ else { /* Lua function */ luaV_finishOp(L); /* finish interrupted instruction */ luaV_execute(L); /* 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 */