module/lua/lstate.h

   1 /* BEGIN CSTYLED */
   2 /*
   3 ** $Id: lstate.h,v 2.82.1.1 2013/04/12 18:48:47 roberto Exp $
   4 ** Global State
   5 ** See Copyright Notice in lua.h
   6 */
   7
   8 #ifndef lstate_h
   9 #define lstate_h
  10
  11 #include <sys/lua/lua.h>
  12
  13 #include "lobject.h"
  14 #include "ltm.h"
  15 #include "lzio.h"
  16
  17
  18 /*
  19
  20 ** Some notes about garbage-collected objects:  All objects in Lua must
  21 ** be kept somehow accessible until being freed.
  22 **
  23 ** Lua keeps most objects linked in list g->allgc. The link uses field
  24 ** 'next' of the CommonHeader.
  25 **
  26 ** Strings are kept in several lists headed by the array g->strt.hash.
  27 **
  28 ** Open upvalues are not subject to independent garbage collection. They
  29 ** are collected together with their respective threads. Lua keeps a
  30 ** double-linked list with all open upvalues (g->uvhead) so that it can
  31 ** mark objects referred by them. (They are always gray, so they must
  32 ** be remarked in the atomic step. Usually their contents would be marked
  33 ** when traversing the respective threads, but the thread may already be
  34 ** dead, while the upvalue is still accessible through closures.)
  35 **
  36 ** Objects with finalizers are kept in the list g->finobj.
  37 **
  38 ** The list g->tobefnz links all objects being finalized.
  39
  40 */
  41
  42
  43 struct lua_longjmp;  /* defined in ldo.c */
  44
  45
  46
  47 /* extra stack space to handle TM calls and some other extras */
  48 #define EXTRA_STACK   5
  49
  50
  51 #define BASIC_STACK_SIZE        (2*LUA_MINSTACK)
  52
  53
  54 /* kinds of Garbage Collection */
  55 #define KGC_NORMAL      0
  56 #define KGC_EMERGENCY   1       /* gc was forced by an allocation failure */
  57 #define KGC_GEN         2       /* generational collection */
  58
  59
  60 typedef struct stringtable {
  61   GCObject **hash;
  62   lu_int32 nuse;  /* number of elements */
  63   int size;
  64 } stringtable;
  65
  66
  67 /*
  68 ** information about a call
  69 */
  70 typedef struct CallInfo {
  71   StkId func;  /* function index in the stack */
  72   StkId top;  /* top for this function */
  73   struct CallInfo *previous, *next;  /* dynamic call link */
  74   short nresults;  /* expected number of results from this function */
  75   lu_byte callstatus;
  76   ptrdiff_t extra;
  77   union {
  78     struct {  /* only for Lua functions */
  79       StkId base;  /* base for this function */
  80       const Instruction *savedpc;
  81     } l;
  82     struct {  /* only for C functions */
  83       int ctx;  /* context info. in case of yields */
  84       lua_CFunction k;  /* continuation in case of yields */
  85       ptrdiff_t old_errfunc;
  86       lu_byte old_allowhook;
  87       lu_byte status;
  88     } c;
  89   } u;
  90 } CallInfo;
  91
  92
  93 /*
  94 ** Bits in CallInfo status
  95 */
  96 #define CIST_LUA        (1<<0)  /* call is running a Lua function */
  97 #define CIST_HOOKED     (1<<1)  /* call is running a debug hook */
  98 #define CIST_REENTRY    (1<<2)  /* call is running on same invocation of
  99                                    luaV_execute of previous call */
 100 #define CIST_YIELDED    (1<<3)  /* call reentered after suspension */
 101 #define CIST_YPCALL     (1<<4)  /* call is a yieldable protected call */
 102 #define CIST_STAT       (1<<5)  /* call has an error status (pcall) */
 103 #define CIST_TAIL       (1<<6)  /* call was tail called */
 104 #define CIST_HOOKYIELD  (1<<7)  /* last hook called yielded */
 105
 106
 107 #define isLua(ci)       ((ci)->callstatus & CIST_LUA)
 108
 109
 110 /*
 111 ** `global state', shared by all threads of this state
 112 */
 113 typedef struct global_State {
 114   lua_Alloc frealloc;  /* function to reallocate memory */
 115   void *ud;         /* auxiliary data to `frealloc' */
 116   lu_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
 117   l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
 118   lu_mem GCmemtrav;  /* memory traversed by the GC */
 119   lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
 120   stringtable strt;  /* hash table for strings */
 121   TValue l_registry;
 122   unsigned int seed;  /* randomized seed for hashes */
 123   lu_byte currentwhite;
 124   lu_byte gcstate;  /* state of garbage collector */
 125   lu_byte gckind;  /* kind of GC running */
 126   lu_byte gcrunning;  /* true if GC is running */
 127   int sweepstrgc;  /* position of sweep in `strt' */
 128   GCObject *allgc;  /* list of all collectable objects */
 129   GCObject *finobj;  /* list of collectable objects with finalizers */
 130   GCObject **sweepgc;  /* current position of sweep in list 'allgc' */
 131   GCObject **sweepfin;  /* current position of sweep in list 'finobj' */
 132   GCObject *gray;  /* list of gray objects */
 133   GCObject *grayagain;  /* list of objects to be traversed atomically */
 134   GCObject *weak;  /* list of tables with weak values */
 135   GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
 136   GCObject *allweak;  /* list of all-weak tables */
 137   GCObject *tobefnz;  /* list of userdata to be GC */
 138   UpVal uvhead;  /* head of double-linked list of all open upvalues */
 139   Mbuffer buff;  /* temporary buffer for string concatenation */
 140   int gcpause;  /* size of pause between successive GCs */
 141   int gcmajorinc;  /* pause between major collections (only in gen. mode) */
 142   int gcstepmul;  /* GC `granularity' */
 143   lua_CFunction panic;  /* to be called in unprotected errors */
 144   struct lua_State *mainthread;
 145   const lua_Number *version;  /* pointer to version number */
 146   TString *memerrmsg;  /* memory-error message */
 147   TString *tmname[TM_N];  /* array with tag-method names */
 148   struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
 149 } global_State;
 150
 151
 152 /*
 153 ** `per thread' state
 154 */
 155 struct lua_State {
 156   CommonHeader;
 157   lu_byte status;
 158   StkId top;  /* first free slot in the stack */
 159   global_State *l_G;
 160   CallInfo *ci;  /* call info for current function */
 161   const Instruction *oldpc;  /* last pc traced */
 162   StkId stack_last;  /* last free slot in the stack */
 163   StkId stack;  /* stack base */
 164   int stacksize;
 165   unsigned short nny;  /* number of non-yieldable calls in stack */
 166   unsigned short nCcalls;  /* number of nested C calls */
 167   lu_byte hookmask;
 168   lu_byte allowhook;
 169   int basehookcount;
 170   int hookcount;
 171   lua_Hook hook;
 172   GCObject *openupval;  /* list of open upvalues in this stack */
 173   GCObject *gclist;
 174   struct lua_longjmp *errorJmp;  /* current error recover point */
 175   ptrdiff_t errfunc;  /* current error handling function (stack index) */
 176   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
 177 };
 178
 179
 180 #define G(L)    (L->l_G)
 181
 182
 183 /*
 184 ** Union of all collectable objects
 185 */
 186 union GCObject {
 187   GCheader gch;  /* common header */
 188   union TString ts;
 189   union Udata u;
 190   union Closure cl;
 191   struct Table h;
 192   struct Proto p;
 193   struct UpVal uv;
 194   struct lua_State th;  /* thread */
 195 };
 196
 197
 198 #define gch(o)          (&(o)->gch)
 199
 200 /* macros to convert a GCObject into a specific value */
 201 #define rawgco2ts(o)  \
 202         check_exp(novariant((o)->gch.tt) == LUA_TSTRING, &((o)->ts))
 203 #define gco2ts(o)       (&rawgco2ts(o)->tsv)
 204 #define rawgco2u(o)     check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u))
 205 #define gco2u(o)        (&rawgco2u(o)->uv)
 206 #define gco2lcl(o)      check_exp((o)->gch.tt == LUA_TLCL, &((o)->cl.l))
 207 #define gco2ccl(o)      check_exp((o)->gch.tt == LUA_TCCL, &((o)->cl.c))
 208 #define gco2cl(o)  \
 209         check_exp(novariant((o)->gch.tt) == LUA_TFUNCTION, &((o)->cl))
 210 #define gco2t(o)        check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h))
 211 #define gco2p(o)        check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p))
 212 #define gco2uv(o)       check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv))
 213 #define gco2th(o)       check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th))
 214
 215 /* macro to convert any Lua object into a GCObject */
 216 #define obj2gco(v)      (cast(GCObject *, (v)))
 217
 218
 219 /* actual number of total bytes allocated */
 220 #define gettotalbytes(g)        ((g)->totalbytes + (g)->GCdebt)
 221
 222 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
 223 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
 224 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
 225 LUAI_FUNC void luaE_freeCI (lua_State *L);
 226
 227
 228 #endif
 229 /* END CSTYLED */