lfunc.c
(5.4.6)
/*
** $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 "ldebug.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 nupvals) {
GCObject *o = luaC_newobj(L, LUA_VCCL, sizeCclosure(nupvals));
CClosure *c = gco2ccl(o);
c->nupvalues = cast_byte(nupvals);
return c;
}
LClosure *luaF_newLclosure (lua_State *L, int nupvals) {
GCObject *o = luaC_newobj(L, LUA_VLCL, sizeLclosure(nupvals));
LClosure *c = gco2lcl(o);
c->p = NULL;
c->nupvalues = cast_byte(nupvals);
while (nupvals--) c->upvals[nupvals] = 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_VUPVAL, sizeof(UpVal));
UpVal *uv = gco2upv(o);
uv->v.p = &uv->u.value; /* make it closed */
setnilvalue(uv->v.p);
cl->upvals[i] = uv;
luaC_objbarrier(L, cl, uv);
}
}
/*
** Create a new upvalue at the given level, and link it to the list of
** open upvalues of 'L' after entry 'prev'.
**/
static UpVal *newupval (lua_State *L, StkId level, UpVal **prev) {
GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
UpVal *uv = gco2upv(o);
UpVal *next = *prev;
uv->v.p = s2v(level); /* current value lives in the stack */
uv->u.open.next = next; /* link it to list of open upvalues */
uv->u.open.previous = prev;
if (next)
next->u.open.previous = &uv->u.open.next;
*prev = uv;
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;
}
/*
** Find and reuse, or create if it does not exist, an upvalue
** at the given level.
*/
UpVal *luaF_findupval (lua_State *L, StkId level) {
UpVal **pp = &L->openupval;
UpVal *p;
lua_assert(isintwups(L) || L->openupval == NULL);
while ((p = *pp) != NULL && uplevel(p) >= level) { /* search for it */
lua_assert(!isdead(G(L), p));
if (uplevel(p) == level) /* corresponding upvalue? */
return p; /* return it */
pp = &p->u.open.next;
}
/* not found: create a new upvalue after 'pp' */
return newupval(L, level, pp);
}
/*
** Call closing method for object 'obj' with error message 'err'. The
** boolean 'yy' controls whether the call is yieldable.
** (This function assumes EXTRA_STACK.)
*/
static void callclosemethod (lua_State *L, TValue *obj, TValue *err, int yy) {
StkId top = L->top.p;
const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
setobj2s(L, top, tm); /* will call metamethod... */
setobj2s(L, top + 1, obj); /* with 'self' as the 1st argument */
setobj2s(L, top + 2, err); /* and error msg. as 2nd argument */
L->top.p = top + 3; /* add function and arguments */
if (yy)
luaD_call(L, top, 0);
else
luaD_callnoyield(L, top, 0);
}
/*
** Check whether object at given level has a close metamethod and raise
** an error if not.
*/
static void checkclosemth (lua_State *L, StkId level) {
const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
if (ttisnil(tm)) { /* no metamethod? */
int idx = cast_int(level - L->ci->func.p); /* variable index */
const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
if (vname == NULL) vname = "?";
luaG_runerror(L, "variable '%s' got a non-closable value", vname);
}
}
/*
** Prepare and call a closing method.
** If status is CLOSEKTOP, the call to the closing method will be pushed
** at the top of the stack. Otherwise, values can be pushed right after
** the 'level' of the upvalue being closed, as everything after that
** won't be used again.
*/
static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
TValue *uv = s2v(level); /* value being closed */
TValue *errobj;
if (status == CLOSEKTOP)
errobj = &G(L)->nilvalue; /* error object is nil */
else { /* 'luaD_seterrorobj' will set top to level + 2 */
errobj = s2v(level + 1); /* error object goes after 'uv' */
luaD_seterrorobj(L, status, level + 1); /* set error object */
}
callclosemethod(L, uv, errobj, yy);
}
/*
** Maximum value for deltas in 'tbclist', dependent on the type
** of delta. (This macro assumes that an 'L' is in scope where it
** is used.)
*/
#define MAXDELTA \
((256ul << ((sizeof(L->stack.p->tbclist.delta) - 1) * 8)) - 1)
/*
** Insert a variable in the list of to-be-closed variables.
*/
void luaF_newtbcupval (lua_State *L, StkId level) {
lua_assert(level > L->tbclist.p);
if (l_isfalse(s2v(level)))
return; /* false doesn't need to be closed */
checkclosemth(L, level); /* value must have a close method */
while (cast_uint(level - L->tbclist.p) > MAXDELTA) {
L->tbclist.p += MAXDELTA; /* create a dummy node at maximum delta */
L->tbclist.p->tbclist.delta = 0;
}
level->tbclist.delta = cast(unsigned short, level - L->tbclist.p);
L->tbclist.p = level;
}
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;
}
/*
** Close all upvalues up to the given stack level.
*/
void luaF_closeupval (lua_State *L, StkId level) {
UpVal *uv;
StkId upl; /* stack index pointed by 'uv' */
while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
TValue *slot = &uv->u.value; /* new position for value */
lua_assert(uplevel(uv) < L->top.p);
luaF_unlinkupval(uv); /* remove upvalue from 'openupval' list */
setobj(L, slot, uv->v.p); /* move value to upvalue slot */
uv->v.p = slot; /* now current value lives here */
if (!iswhite(uv)) { /* neither white nor dead? */
nw2black(uv); /* closed upvalues cannot be gray */
luaC_barrier(L, uv, slot);
}
}
}
/*
** Remove first element from the tbclist plus its dummy nodes.
*/
static void poptbclist (lua_State *L) {
StkId tbc = L->tbclist.p;
lua_assert(tbc->tbclist.delta > 0); /* first element cannot be dummy */
tbc -= tbc->tbclist.delta;
while (tbc > L->stack.p && tbc->tbclist.delta == 0)
tbc -= MAXDELTA; /* remove dummy nodes */
L->tbclist.p = tbc;
}
/*
** Close all upvalues and to-be-closed variables up to the given stack
** level. Return restored 'level'.
*/
StkId luaF_close (lua_State *L, StkId level, int status, int yy) {
ptrdiff_t levelrel = savestack(L, level);
luaF_closeupval(L, level); /* first, close the upvalues */
while (L->tbclist.p >= level) { /* traverse tbc's down to that level */
StkId tbc = L->tbclist.p; /* get variable index */
poptbclist(L); /* remove it from list */
prepcallclosemth(L, tbc, status, yy); /* close variable */
level = restorestack(L, levelrel);
}
return level;
}
Proto *luaF_newproto (lua_State *L) {
GCObject *o = luaC_newobj(L, LUA_VPROTO, sizeof(Proto));
Proto *f = gco2p(o);
f->k = NULL;
f->sizek = 0;
f->p = NULL;
f->sizep = 0;
f->code = NULL;
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 */
}