/*

** $Id: lstate.c,v 2.36.1.2 2008/01/03 15:20:39 roberto Exp $

** Global State

** See Copyright Notice in lua.h

*/

#include <stddef.h>

#define lstate_c

#define LUA_CORE

#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"

#define state_size(x)   (sizeof(x) + LUAI_EXTRASPACE)

#define fromstate(l)    (cast(lu_byte *, (l)) - LUAI_EXTRASPACE)

#define tostate(l)   (cast(lua_State *, cast(lu_byte *, l) + LUAI_EXTRASPACE))

/*

** Main thread combines a thread state and the global state

*/

typedef struct LG {

  lua_State l;

  global_State g;

} LG;

static void stack_init (lua_State *L1, lua_State *L) {

  /* initialize CallInfo array */

  L1->base_ci = luaM_newvector(L, BASIC_CI_SIZE, CallInfo);

  L1->ci = L1->base_ci;

  L1->size_ci = BASIC_CI_SIZE;

  L1->end_ci = L1->base_ci + L1->size_ci - 1;

  /* initialize stack array */

  L1->stack = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, TValue);

  L1->stacksize = BASIC_STACK_SIZE + EXTRA_STACK;

  L1->top = L1->stack;

  L1->stack_last = L1->stack+(L1->stacksize - EXTRA_STACK)-1;

  /* initialize first ci */

  L1->ci->func = L1->top;

  setnilvalue(L1->top++);  /* `function' entry for this `ci' */

  L1->base = L1->ci->base = L1->top;

  L1->ci->top = L1->top + LUA_MINSTACK;

}

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, TValue);

}

/*

** open parts that may cause memory-allocation errors

*/

static void f_luaopen (lua_State *L, void *ud) {

  global_State *g = G(L);

  UNUSED(ud);

  stack_init(L, L);  /* init stack */

  sethvalue(L, gt(L), luaH_new(L, 0, 2));  /* table of globals */

  sethvalue(L, registry(L), luaH_new(L, 0, 2));  /* 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->totalbytes;

}

static void preinit_state (lua_State *L, global_State *g) {

  G(L) = g;

  L->stack = NULL;

  L->stacksize = 0;

  L->errorJmp = NULL;

  L->hook = NULL;

  L->hookmask = 0;

  L->basehookcount = 0;

  L->allowhook = 1;

  resethookcount(L);

  L->openupval = NULL;

  L->size_ci = 0;

  L->nCcalls = L->baseCcalls = 0;

  L->status = 0;

  L->base_ci = L->ci = NULL;

  L->savedpc = NULL;

  L->errfunc = 0;

  setnilvalue(gt(L));

}

static void close_state (lua_State *L) {

  global_State *g = G(L);

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

  luaC_freeall(L);  /* collect all objects */

  lua_assert(g->rootgc == obj2gco(L));

  lua_assert(g->strt.nuse == 0);

  luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);

  luaZ_freebuffer(L, &g->buff);

  freestack(L, L);

  lua_assert(g->totalbytes == sizeof(LG));

  (*g->frealloc)(g->ud, fromstate(L), state_size(LG), 0);

}

lua_State *luaE_newthread (lua_State *L) {

  lua_State *L1 = tostate(luaM_malloc(L, state_size(lua_State)));

  luaC_link(L, obj2gco(L1), LUA_TTHREAD);

  preinit_state(L1, G(L));

  stack_init(L1, L);  /* init stack */

  setobj2n(L, gt(L1), gt(L));  /* share table of globals */

  L1->hookmask = L->hookmask;

  L1->basehookcount = L->basehookcount;

  L1->hook = L->hook;

  resethookcount(L1);

  lua_assert(iswhite(obj2gco(L1)));

  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);

  luai_userstatefree(L1);

  freestack(L, L1);

  luaM_freemem(L, fromstate(L1), state_size(lua_State));

}

LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {

  int i;

  lua_State *L;

  global_State *g;

  void *l = (*f)(ud, NULL, 0, state_size(LG));

  if (l == NULL) return NULL;

  L = tostate(l);

  g = &((LG *)L)->g;

  L->next = NULL;

  L->tt = LUA_TTHREAD;

  g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);

  L->marked = luaC_white(g);

  set2bits(L->marked, FIXEDBIT, SFIXEDBIT);

  preinit_state(L, g);

  g->frealloc = f;

  g->ud = ud;

  g->mainthread = L;

  g->uvhead.u.l.prev = &g->uvhead;

  g->uvhead.u.l.next = &g->uvhead;

  g->GCthreshold = 0;  /* mark it as unfinished state */

  g->strt.size = 0;

  g->strt.nuse = 0;

  g->strt.hash = NULL;

  setnilvalue(registry(L));

  luaZ_initbuffer(L, &g->buff);

  g->panic = NULL;

  g->gcstate = GCSpause;

  g->rootgc = obj2gco(L);

  g->sweepstrgc = 0;

  g->sweepgc = &g->rootgc;

  g->gray = NULL;

  g->grayagain = NULL;

  g->weak = NULL;

  g->tmudata = NULL;

  g->totalbytes = sizeof(LG);

  g->gcpause = LUAI_GCPAUSE;

  g->gcstepmul = LUAI_GCMUL;

  g->gcdept = 0;

  for (i=0; i<NUM_TAGS; i++) g->mt[i] = NULL;

  if (luaD_rawrunprotected(L, f_luaopen, NULL) != 0) {

    /* memory allocation error: free partial state */

    close_state(L);

    L = NULL;

  }

  else

    luai_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) {

  L = G(L)->mainthread;  /* only the main thread can be closed */

  lua_lock(L);

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

  luaC_separateudata(L, 1);  /* 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 = L->baseCcalls = 0;

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

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

  luai_userstateclose(L);

  close_state(L);

}