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