lstate.c

   1 /*
   2 ** $Id: lstate.c,v 2.36.1.2 2008/01/03 15:20:39 roberto Exp $
   3 ** Global State
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <stddef.h>
   9
  10 #define lstate_c
  11 #define LUA_CORE
  12
  13 #include "lua.h"
  14
  15 #include "ldebug.h"
  16 #include "ldo.h"
  17 #include "lfunc.h"
  18 #include "lgc.h"
  19 #include "llex.h"
  20 #include "lmem.h"
  21 #include "lstate.h"
  22 #include "lstring.h"
  23 #include "ltable.h"
  24 #include "ltm.h"
  25
  26
  27 #define state_size(x)   (sizeof(x) + LUAI_EXTRASPACE)
  28 #define fromstate(l)    (cast(lu_byte *, (l)) - LUAI_EXTRASPACE)
  29 #define tostate(l)   (cast(lua_State *, cast(lu_byte *, l) + LUAI_EXTRASPACE))
  30
  31
  32 /*
  33 ** Main thread combines a thread state and the global state
  34 */
  35 typedef struct LG {
  36   lua_State l;
  37   global_State g;
  38 } LG;
  39
  40
  41
  42 static void stack_init (lua_State *L1, lua_State *L) {
  43   /* initialize CallInfo array */
  44   L1->base_ci = luaM_newvector(L, BASIC_CI_SIZE, CallInfo);
  45   L1->ci = L1->base_ci;
  46   L1->size_ci = BASIC_CI_SIZE;
  47   L1->end_ci = L1->base_ci + L1->size_ci - 1;
  48   /* initialize stack array */
  49   L1->stack = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, TValue);
  50   L1->stacksize = BASIC_STACK_SIZE + EXTRA_STACK;
  51   L1->top = L1->stack;
  52   L1->stack_last = L1->stack+(L1->stacksize - EXTRA_STACK)-1;
  53   /* initialize first ci */
  54   L1->ci->func = L1->top;
  55   setnilvalue(L1->top++);  /* `function' entry for this `ci' */
  56   L1->base = L1->ci->base = L1->top;
  57   L1->ci->top = L1->top + LUA_MINSTACK;
  58 }
  59
  60
  61 static void freestack (lua_State *L, lua_State *L1) {
  62   luaM_freearray(L, L1->base_ci, L1->size_ci, CallInfo);
  63   luaM_freearray(L, L1->stack, L1->stacksize, TValue);
  64 }
  65
  66
  67 /*
  68 ** open parts that may cause memory-allocation errors
  69 */
  70 static void f_luaopen (lua_State *L, void *ud) {
  71   global_State *g = G(L);
  72   UNUSED(ud);
  73   stack_init(L, L);  /* init stack */
  74   sethvalue(L, gt(L), luaH_new(L, 0, 2));  /* table of globals */
  75   sethvalue(L, registry(L), luaH_new(L, 0, 2));  /* registry */
  76   luaS_resize(L, MINSTRTABSIZE);  /* initial size of string table */
  77   luaT_init(L);
  78   luaX_init(L);
  79   luaS_fix(luaS_newliteral(L, MEMERRMSG));
  80   g->GCthreshold = 4*g->totalbytes;
  81 }
  82
  83
  84 static void preinit_state (lua_State *L, global_State *g) {
  85   G(L) = g;
  86   L->stack = NULL;
  87   L->stacksize = 0;
  88   L->errorJmp = NULL;
  89   L->hook = NULL;
  90   L->hookmask = 0;
  91   L->basehookcount = 0;
  92   L->allowhook = 1;
  93   resethookcount(L);
  94   L->openupval = NULL;
  95   L->size_ci = 0;
  96   L->nCcalls = L->baseCcalls = 0;
  97   L->status = 0;
  98   L->base_ci = L->ci = NULL;
  99   L->savedpc = NULL;
 100   L->errfunc = 0;
 101   setnilvalue(gt(L));
 102 }
 103
 104
 105 static void close_state (lua_State *L) {
 106   global_State *g = G(L);
 107   luaF_close(L, L->stack);  /* close all upvalues for this thread */
 108   luaC_freeall(L);  /* collect all objects */
 109   lua_assert(g->rootgc == obj2gco(L));
 110   lua_assert(g->strt.nuse == 0);
 111   luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
 112   luaZ_freebuffer(L, &g->buff);
 113   freestack(L, L);
 114   lua_assert(g->totalbytes == sizeof(LG));
 115   (*g->frealloc)(g->ud, fromstate(L), state_size(LG), 0);
 116 }
 117
 118
 119 lua_State *luaE_newthread (lua_State *L) {
 120   lua_State *L1 = tostate(luaM_malloc(L, state_size(lua_State)));
 121   luaC_link(L, obj2gco(L1), LUA_TTHREAD);
 122   preinit_state(L1, G(L));
 123   stack_init(L1, L);  /* init stack */
 124   setobj2n(L, gt(L1), gt(L));  /* share table of globals */
 125   L1->hookmask = L->hookmask;
 126   L1->basehookcount = L->basehookcount;
 127   L1->hook = L->hook;
 128   resethookcount(L1);
 129   lua_assert(iswhite(obj2gco(L1)));
 130   return L1;
 131 }
 132
 133
 134 void luaE_freethread (lua_State *L, lua_State *L1) {
 135   luaF_close(L1, L1->stack);  /* close all upvalues for this thread */
 136   lua_assert(L1->openupval == NULL);
 137   luai_userstatefree(L1);
 138   freestack(L, L1);
 139   luaM_freemem(L, fromstate(L1), state_size(lua_State));
 140 }
 141
 142
 143 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
 144   int i;
 145   lua_State *L;
 146   global_State *g;
 147   void *l = (*f)(ud, NULL, 0, state_size(LG));
 148   if (l == NULL) return NULL;
 149   L = tostate(l);
 150   g = &((LG *)L)->g;
 151   L->next = NULL;
 152   L->tt = LUA_TTHREAD;
 153   g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
 154   L->marked = luaC_white(g);
 155   set2bits(L->marked, FIXEDBIT, SFIXEDBIT);
 156   preinit_state(L, g);
 157   g->frealloc = f;
 158   g->ud = ud;
 159   g->mainthread = L;
 160   g->uvhead.u.l.prev = &g->uvhead;
 161   g->uvhead.u.l.next = &g->uvhead;
 162   g->GCthreshold = 0;  /* mark it as unfinished state */
 163   g->strt.size = 0;
 164   g->strt.nuse = 0;
 165   g->strt.hash = NULL;
 166   setnilvalue(registry(L));
 167   luaZ_initbuffer(L, &g->buff);
 168   g->panic = NULL;
 169   g->gcstate = GCSpause;
 170   g->rootgc = obj2gco(L);
 171   g->sweepstrgc = 0;
 172   g->sweepgc = &g->rootgc;
 173   g->gray = NULL;
 174   g->grayagain = NULL;
 175   g->weak = NULL;
 176   g->tmudata = NULL;
 177   g->totalbytes = sizeof(LG);
 178   g->gcpause = LUAI_GCPAUSE;
 179   g->gcstepmul = LUAI_GCMUL;
 180   g->gcdept = 0;
 181   for (i=0; i<NUM_TAGS; i++) g->mt[i] = NULL;
 182   if (luaD_rawrunprotected(L, f_luaopen, NULL) != 0) {
 183     /* memory allocation error: free partial state */
 184     close_state(L);
 185     L = NULL;
 186   }
 187   else
 188     luai_userstateopen(L);
 189   return L;
 190 }
 191
 192
 193 static void callallgcTM (lua_State *L, void *ud) {
 194   UNUSED(ud);
 195   luaC_callGCTM(L);  /* call GC metamethods for all udata */
 196 }
 197
 198
 199 LUA_API void lua_close (lua_State *L) {
 200   L = G(L)->mainthread;  /* only the main thread can be closed */
 201   lua_lock(L);
 202   luaF_close(L, L->stack);  /* close all upvalues for this thread */
 203   luaC_separateudata(L, 1);  /* separate udata that have GC metamethods */
 204   L->errfunc = 0;  /* no error function during GC metamethods */
 205   do {  /* repeat until no more errors */
 206     L->ci = L->base_ci;
 207     L->base = L->top = L->ci->base;
 208     L->nCcalls = L->baseCcalls = 0;
 209   } while (luaD_rawrunprotected(L, callallgcTM, NULL) != 0);
 210   lua_assert(G(L)->tmudata == NULL);
 211   luai_userstateclose(L);
 212   close_state(L);
 213 }