ref: 8b4a3db418e246dc07abd839776df99dfc38498d
dir: /lfunc.c/
/*
** $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 = &uv->u.value; /* make it closed */
setnilvalue(uv->v);
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, int tbc, StkId level, UpVal **prev) {
GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
UpVal *uv = gco2upv(o);
UpVal *next = *prev;
uv->v = s2v(level); /* current value lives in the stack */
uv->tbc = tbc;
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, 0, level, pp);
}
static void callclose (lua_State *L, void *ud) {
UNUSED(ud);
luaD_callnoyield(L, L->top - 3, 0);
}
/*
** Prepare closing method plus its arguments for object 'obj' with
** error message 'err'. (This function assumes EXTRA_STACK.)
*/
static int prepclosingmethod (lua_State *L, TValue *obj, TValue *err) {
StkId top = L->top;
const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
if (ttisnil(tm)) /* no metamethod? */
return 0; /* nothing to call */
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 = top + 3; /* add function and arguments */
return 1;
}
/*
** Raise an error with message 'msg', inserting the name of the
** local variable at position 'level' in the stack.
*/
static void varerror (lua_State *L, StkId level, const char *msg) {
int idx = cast_int(level - L->ci->func);
const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
if (vname == NULL) vname = "?";
luaG_runerror(L, msg, vname);
}
/*
** Prepare and call a closing method. If status is OK, code is still
** inside the original protected call, and so any error will be handled
** there. Otherwise, a previous error already activated the original
** protected call, and so the call to the closing method must be
** protected here. (A status == CLOSEPROTECT behaves like a previous
** error, to also run the closing method in protected mode).
** If status is OK, the call to the closing method will be pushed
** at the top of the stack. Otherwise, values are pushed after
** the 'level' of the upvalue being closed, as everything after
** that won't be used again.
*/
static int callclosemth (lua_State *L, StkId level, int status) {
TValue *uv = s2v(level); /* value being closed */
if (likely(status == LUA_OK)) {
if (prepclosingmethod(L, uv, &G(L)->nilvalue)) /* something to call? */
callclose(L, NULL); /* call closing method */
else if (!l_isfalse(uv)) /* non-closable non-false value? */
varerror(L, level, "attempt to close non-closable variable '%s'");
}
else { /* must close the object in protected mode */
ptrdiff_t oldtop;
level++; /* space for error message */
oldtop = savestack(L, level + 1); /* top will be after that */
luaD_seterrorobj(L, status, level); /* set error message */
if (prepclosingmethod(L, uv, s2v(level))) { /* something to call? */
int newstatus = luaD_pcall(L, callclose, NULL, oldtop, 0);
if (newstatus != LUA_OK && status == CLOSEPROTECT) /* first error? */
status = newstatus; /* this will be the new error */
else {
if (newstatus != LUA_OK) /* suppressed error? */
luaE_warnerror(L, "__close metamethod");
/* leave original error (or nil) on top */
L->top = restorestack(L, oldtop);
}
}
/* else no metamethod; ignore this case and keep original error */
}
return status;
}
/*
** Try to create a to-be-closed upvalue
** (can raise a memory-allocation error)
*/
static void trynewtbcupval (lua_State *L, void *ud) {
newupval(L, 1, cast(StkId, ud), &L->openupval);
}
/*
** Create a to-be-closed upvalue. If there is a memory error
** when creating the upvalue, the closing method must be called here,
** as there is no upvalue to call it later.
*/
void luaF_newtbcupval (lua_State *L, StkId level) {
TValue *obj = s2v(level);
lua_assert(L->openupval == NULL || uplevel(L->openupval) < level);
if (!l_isfalse(obj)) { /* false doesn't need to be closed */
int status;
const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
if (ttisnil(tm)) /* no metamethod? */
varerror(L, level, "variable '%s' got a non-closable value");
status = luaD_rawrunprotected(L, trynewtbcupval, level);
if (unlikely(status != LUA_OK)) { /* memory error creating upvalue? */
lua_assert(status == LUA_ERRMEM);
luaD_seterrorobj(L, LUA_ERRMEM, level + 1); /* save error message */
/* next call must succeed, as object is closable */
prepclosingmethod(L, s2v(level), s2v(level + 1));
callclose(L, NULL); /* call closing method */
luaD_throw(L, LUA_ERRMEM); /* throw memory error */
}
}
}
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) {
TValue *slot = &uv->u.value; /* new position for value */
lua_assert(uplevel(uv) < L->top);
if (uv->tbc && status != NOCLOSINGMETH) {
/* must run closing method, which may change the stack */
ptrdiff_t levelrel = savestack(L, level);
status = callclosemth(L, uplevel(uv), status);
level = restorestack(L, levelrel);
}
luaF_unlinkupval(uv);
setobj(L, slot, uv->v); /* move value to upvalue slot */
uv->v = 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);
}
}
return status;
}
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 */
}