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/*
** $Id: lfunc.c $
** Auxiliary functions to manipulate prototypes and closures
** See Copyright Notice in lua.h
*/
#define lfunc_c
#define LUA_CORE
#include "lprefix.h"
#include <stddef.h>
#include "lua.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
CClosure *luaF_newCclosure (lua_State *L, int n) {
GCObject *o = luaC_newobj(L, LUA_TCCL, sizeCclosure(n));
CClosure *c = gco2ccl(o);
c->nupvalues = cast_byte(n);
return c;
}
LClosure *luaF_newLclosure (lua_State *L, int n) {
GCObject *o = luaC_newobj(L, LUA_TLCL, sizeLclosure(n));
LClosure *c = gco2lcl(o);
c->p = NULL;
c->nupvalues = cast_byte(n);
while (n--) c->upvals[n] = NULL;
return c;
}
/*
** fill a closure with new closed upvalues
*/
void luaF_initupvals (lua_State *L, LClosure *cl) {
int i;
for (i = 0; i < cl->nupvalues; i++) {
GCObject *o = luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal));
UpVal *uv = gco2upv(o);
uv->v = &uv->u.value; /* make it closed */
setnilvalue(uv->v);
cl->upvals[i] = uv;
luaC_objbarrier(L, cl, o);
}
}
UpVal *luaF_findupval (lua_State *L, StkId level) {
UpVal **pp = &L->openupval;
GCObject *o;
UpVal *p;
UpVal *uv;
lua_assert(isintwups(L) || L->openupval == NULL);
while ((p = *pp) != NULL && uplevel(p) >= level) {
if (uplevel(p) == level && !isdead(G(L), p)) /* corresponding upvalue? */
return p; /* return it */
pp = &p->u.open.next;
}
/* not found: create a new upvalue between 'pp' and 'p' */
o = luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal));
uv = gco2upv(o);
uv->u.open.next = p; /* link it to list of open upvalues */
uv->u.open.previous = pp;
if (p)
p->u.open.previous = &uv->u.open.next;
*pp = uv;
uv->v = s2v(level); /* current value lives in the stack */
if (!isintwups(L)) { /* thread not in list of threads with upvalues? */
L->twups = G(L)->twups; /* link it to the list */
G(L)->twups = L;
}
return uv;
}
static void callclose (lua_State *L, void *ud) {
luaD_callnoyield(L, cast(StkId, ud), 0);
}
static int closeupval (lua_State *L, UpVal *uv, StkId level, int status) {
StkId func = level + 1; /* save slot for old error message */
if (status != LUA_OK) /* was there an error? */
luaD_seterrorobj(L, status, level); /* save error message */
else
setnilvalue(s2v(level));
if (ttisfunction(uv->v)) { /* object to-be-closed is a function? */
setobj2s(L, func, uv->v); /* will call it */
setobjs2s(L, func + 1, level); /* error msg. as argument */
}
else { /* try '__close' metamethod */
const TValue *tm = luaT_gettmbyobj(L, uv->v, TM_CLOSE);
if (ttisnil(tm))
return status; /* no metamethod */
setobj2s(L, func, tm); /* will call metamethod */
setobj2s(L, func + 1, uv->v); /* with 'self' as argument */
}
L->top = func + 2; /* add function and argument */
if (status == LUA_OK) /* not in "error mode"? */
callclose(L, func); /* call closing method */
else { /* already inside error handler; cannot raise another error */
int newstatus = luaD_pcall(L, callclose, func, savestack(L, level), 0);
if (newstatus != LUA_OK) /* error when closing? */
status = newstatus; /* this will be the new error */
}
return status;
}
void luaF_unlinkupval (UpVal *uv) {
lua_assert(upisopen(uv));
*uv->u.open.previous = uv->u.open.next;
if (uv->u.open.next)
uv->u.open.next->u.open.previous = uv->u.open.previous;
}
int luaF_close (lua_State *L, StkId level, int status) {
UpVal *uv;
while ((uv = L->openupval) != NULL && uplevel(uv) >= level) {
StkId upl = uplevel(uv);
TValue *slot = &uv->u.value; /* new position for value */
luaF_unlinkupval(uv);
setobj(L, slot, uv->v); /* move value to upvalue slot */
uv->v = slot; /* now current value lives here */
if (!iswhite(uv))
gray2black(uv); /* closed upvalues cannot be gray */
luaC_barrier(L, uv, slot);
if (status >= 0 && uv->tt == LUA_TUPVALTBC) { /* must be closed? */
ptrdiff_t levelrel = savestack(L, level);
status = closeupval(L, uv, upl, status); /* may reallocate the stack */
level = restorestack(L, levelrel);
}
}
return status;
}
Proto *luaF_newproto (lua_State *L) {
GCObject *o = luaC_newobj(L, LUA_TPROTO, sizeof(Proto));
Proto *f = gco2p(o);
f->k = NULL;
f->sizek = 0;
f->p = NULL;
f->sizep = 0;
f->code = NULL;
f->cache = NULL;
f->cachemiss = 0;
f->sizecode = 0;
f->lineinfo = NULL;
f->sizelineinfo = 0;
f->abslineinfo = NULL;
f->sizeabslineinfo = 0;
f->upvalues = NULL;
f->sizeupvalues = 0;
f->numparams = 0;
f->is_vararg = 0;
f->maxstacksize = 0;
f->locvars = NULL;
f->sizelocvars = 0;
f->linedefined = 0;
f->lastlinedefined = 0;
f->source = NULL;
return f;
}
void luaF_freeproto (lua_State *L, Proto *f) {
luaM_freearray(L, f->code, f->sizecode);
luaM_freearray(L, f->p, f->sizep);
luaM_freearray(L, f->k, f->sizek);
luaM_freearray(L, f->lineinfo, f->sizelineinfo);
luaM_freearray(L, f->abslineinfo, f->sizeabslineinfo);
luaM_freearray(L, f->locvars, f->sizelocvars);
luaM_freearray(L, f->upvalues, f->sizeupvalues);
luaM_free(L, f);
}
/*
** Look for n-th local variable at line 'line' in function 'func'.
** Returns NULL if not found.
*/
const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
int i;
for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
if (pc < f->locvars[i].endpc) { /* is variable active? */
local_number--;
if (local_number == 0)
return getstr(f->locvars[i].varname);
}
}
return NULL; /* not found */
}
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