/*

** $Id: lstate.c,v 1.123 2003/04/03 13:35:34 roberto Exp $

** 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(gkey(g->dummynode));

  setnilvalue(gval(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 */

  luaF_close(L, L->stack);  /* close all upvalues for this thread */

  luaC_separateudata(L);  /* separate udata that have GC metamethods */

  L->errfunc = 0;  /* no error function during GC metamethods */

  do {  /* repeat until no more errors */

    L->ci = L->base_ci;

    L->base = L->top = L->ci->base;

    L->nCcalls = 0;

  } while (luaD_rawrunprotected(L, callallgcTM, NULL) != 0);

  lua_assert(G(L)->tmudata == NULL);

  close_state(L);

}



