lua/lstate.c
Roberto Ierusalimschy e75a6ae9ee `defaultmeta' is always empty, but registry needs some space for
names and numbers (references)
2003-02-13 14:07:57 -02:00

216 lines
5.4 KiB
C

/*
** $Id: lstate.c,v 1.119 2003/02/10 17:32:50 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#define lstate_c
#include "lua.h"
#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "llex.h"
#include "lmem.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
/*
** macro to allow the inclusion of user information in Lua state
*/
#ifndef LUA_USERSTATE
#define EXTRASPACE 0
#else
union UEXTRASPACE {L_Umaxalign a; LUA_USERSTATE b;};
#define EXTRASPACE (sizeof(union UEXTRASPACE))
#endif
/*
** you can change this function through the official API:
** call `lua_setpanicf'
*/
static int default_panic (lua_State *L) {
UNUSED(L);
return 0;
}
static lua_State *mallocstate (lua_State *L) {
lu_byte *block = (lu_byte *)luaM_malloc(L, sizeof(lua_State) + EXTRASPACE);
if (block == NULL) return NULL;
else {
block += EXTRASPACE;
return cast(lua_State *, block);
}
}
static void freestate (lua_State *L, lua_State *L1) {
luaM_free(L, cast(lu_byte *, L1) - EXTRASPACE,
sizeof(lua_State) + EXTRASPACE);
}
static void stack_init (lua_State *L1, lua_State *L) {
L1->stack = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, TObject);
L1->stacksize = BASIC_STACK_SIZE + EXTRA_STACK;
L1->top = L1->stack;
L1->stack_last = L1->stack+(L1->stacksize - EXTRA_STACK)-1;
L1->base_ci = luaM_newvector(L, BASIC_CI_SIZE, CallInfo);
L1->ci = L1->base_ci;
L1->ci->state = CI_C; /* not a Lua function */
setnilvalue(L1->top++); /* `function' entry for this `ci' */
L1->base = L1->ci->base = L1->top;
L1->ci->top = L1->top + LUA_MINSTACK;
L1->size_ci = BASIC_CI_SIZE;
L1->end_ci = L1->base_ci + L1->size_ci;
}
static void freestack (lua_State *L, lua_State *L1) {
luaM_freearray(L, L1->base_ci, L1->size_ci, CallInfo);
luaM_freearray(L, L1->stack, L1->stacksize, TObject);
}
/*
** open parts that may cause memory-allocation errors
*/
static void f_luaopen (lua_State *L, void *ud) {
/* create a new global state */
global_State *g = luaM_new(NULL, global_State);
UNUSED(ud);
if (g == NULL) luaD_throw(L, LUA_ERRMEM);
L->l_G = g;
g->mainthread = L;
g->GCthreshold = 0; /* mark it as unfinished state */
g->strt.size = 0;
g->strt.nuse = 0;
g->strt.hash = NULL;
setnilvalue(defaultmeta(L));
setnilvalue(registry(L));
luaZ_initbuffer(L, &g->buff);
g->panic = &default_panic;
g->rootgc = NULL;
g->rootudata = NULL;
g->tmudata = NULL;
setnilvalue(key(g->dummynode));
setnilvalue(val(g->dummynode));
g->dummynode->next = NULL;
g->nblocks = sizeof(lua_State) + sizeof(global_State);
stack_init(L, L); /* init stack */
/* create default meta table with a dummy table, and then close the loop */
defaultmeta(L)->tt = LUA_TTABLE;
sethvalue(defaultmeta(L), luaH_new(L, 0, 0));
hvalue(defaultmeta(L))->metatable = hvalue(defaultmeta(L));
sethvalue(gt(L), luaH_new(L, 0, 4)); /* table of globals */
sethvalue(registry(L), luaH_new(L, 4, 4)); /* registry */
luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */
luaT_init(L);
luaX_init(L);
luaS_fix(luaS_newliteral(L, MEMERRMSG));
g->GCthreshold = 4*G(L)->nblocks;
}
static void preinit_state (lua_State *L) {
L->stack = NULL;
L->stacksize = 0;
L->errorJmp = NULL;
L->hook = NULL;
L->hookmask = L->hookinit = 0;
L->basehookcount = 0;
L->allowhook = 1;
resethookcount(L);
L->openupval = NULL;
L->size_ci = 0;
L->nCcalls = 0;
L->base_ci = L->ci = NULL;
L->errfunc = 0;
setnilvalue(gt(L));
}
static void close_state (lua_State *L) {
luaF_close(L, L->stack); /* close all upvalues for this thread */
if (G(L)) { /* close global state */
luaC_sweep(L, 1); /* collect all elements */
lua_assert(G(L)->rootgc == NULL);
lua_assert(G(L)->rootudata == NULL);
luaS_freeall(L);
luaZ_freebuffer(L, &G(L)->buff);
}
freestack(L, L);
if (G(L)) {
lua_assert(G(L)->nblocks == sizeof(lua_State) + sizeof(global_State));
luaM_freelem(NULL, G(L));
}
freestate(NULL, L);
}
lua_State *luaE_newthread (lua_State *L) {
lua_State *L1 = mallocstate(L);
luaC_link(L, valtogco(L1), LUA_TTHREAD);
preinit_state(L1);
L1->l_G = L->l_G;
stack_init(L1, L); /* init stack */
setobj2n(gt(L1), gt(L)); /* share table of globals */
return L1;
}
void luaE_freethread (lua_State *L, lua_State *L1) {
luaF_close(L1, L1->stack); /* close all upvalues for this thread */
lua_assert(L1->openupval == NULL);
freestack(L, L1);
freestate(L, L1);
}
LUA_API lua_State *lua_open (void) {
lua_State *L = mallocstate(NULL);
if (L) { /* allocation OK? */
L->tt = LUA_TTHREAD;
L->marked = 0;
L->next = L->gclist = NULL;
preinit_state(L);
L->l_G = NULL;
if (luaD_rawrunprotected(L, f_luaopen, NULL) != 0) {
/* memory allocation error: free partial state */
close_state(L);
L = NULL;
}
}
lua_userstateopen(L);
return L;
}
static void callallgcTM (lua_State *L, void *ud) {
UNUSED(ud);
luaC_callGCTM(L); /* call GC metamethods for all udata */
}
LUA_API void lua_close (lua_State *L) {
lua_lock(L);
L = G(L)->mainthread; /* only the main thread can be closed */
luaC_separateudata(L); /* separate udata that have GC metamethods */
/* repeat until no more errors */
while (luaD_rawrunprotected(L, callallgcTM, NULL) != 0) /* skip */;
lua_assert(G(L)->tmudata == NULL);
close_state(L);
}