ceph/src/lua/src/lstate.h

   1 /*
   2 ** $Id: lstate.h,v 2.128 2015/11/13 12:16:51 roberto Exp $
   3 ** Global State
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #ifndef lstate_h
   8 #define lstate_h
   9
  10 #include "lua.h"
  11
  12 #include "lobject.h"
  13 #include "ltm.h"
  14 #include "lzio.h"
  15
  16
  17 /*
  18
  19 ** Some notes about garbage-collected objects: All objects in Lua must
  20 ** be kept somehow accessible until being freed, so all objects always
  21 ** belong to one (and only one) of these lists, using field 'next' of
  22 ** the 'CommonHeader' for the link:
  23 **
  24 ** 'allgc': all objects not marked for finalization;
  25 ** 'finobj': all objects marked for finalization;
  26 ** 'tobefnz': all objects ready to be finalized;
  27 ** 'fixedgc': all objects that are not to be collected (currently
  28 ** only small strings, such as reserved words).
  29
  30 */
  31
  32
  33 struct lua_longjmp;  /* defined in ldo.c */
  34
  35
  36
  37 /* extra stack space to handle TM calls and some other extras */
  38 #define EXTRA_STACK   5
  39
  40
  41 #define BASIC_STACK_SIZE        (2*LUA_MINSTACK)
  42
  43
  44 /* kinds of Garbage Collection */
  45 #define KGC_NORMAL      0
  46 #define KGC_EMERGENCY   1       /* gc was forced by an allocation failure */
  47
  48
  49 typedef struct stringtable {
  50   TString **hash;
  51   int nuse;  /* number of elements */
  52   int size;
  53 } stringtable;
  54
  55
  56 /*
  57 ** Information about a call.
  58 ** When a thread yields, 'func' is adjusted to pretend that the
  59 ** top function has only the yielded values in its stack; in that
  60 ** case, the actual 'func' value is saved in field 'extra'.
  61 ** When a function calls another with a continuation, 'extra' keeps
  62 ** the function index so that, in case of errors, the continuation
  63 ** function can be called with the correct top.
  64 */
  65 typedef struct CallInfo {
  66   StkId func;  /* function index in the stack */
  67   StkId top;  /* top for this function */
  68   struct CallInfo *previous, *next;  /* dynamic call link */
  69   union {
  70     struct {  /* only for Lua functions */
  71       StkId base;  /* base for this function */
  72       const Instruction *savedpc;
  73     } l;
  74     struct {  /* only for C functions */
  75       lua_KFunction k;  /* continuation in case of yields */
  76       ptrdiff_t old_errfunc;
  77       lua_KContext ctx;  /* context info. in case of yields */
  78     } c;
  79   } u;
  80   ptrdiff_t extra;
  81   short nresults;  /* expected number of results from this function */
  82   lu_byte callstatus;
  83 } CallInfo;
  84
  85
  86 /*
  87 ** Bits in CallInfo status
  88 */
  89 #define CIST_OAH        (1<<0)  /* original value of 'allowhook' */
  90 #define CIST_LUA        (1<<1)  /* call is running a Lua function */
  91 #define CIST_HOOKED     (1<<2)  /* call is running a debug hook */
  92 #define CIST_FRESH      (1<<3)  /* call is running on a fresh invocation
  93                                    of luaV_execute */
  94 #define CIST_YPCALL     (1<<4)  /* call is a yieldable protected call */
  95 #define CIST_TAIL       (1<<5)  /* call was tail called */
  96 #define CIST_HOOKYIELD  (1<<6)  /* last hook called yielded */
  97 #define CIST_LEQ        (1<<7)  /* using __lt for __le */
  98
  99 #define isLua(ci)       ((ci)->callstatus & CIST_LUA)
 100
 101 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */
 102 #define setoah(st,v)    ((st) = ((st) & ~CIST_OAH) | (v))
 103 #define getoah(st)      ((st) & CIST_OAH)
 104
 105
 106 /*
 107 ** 'global state', shared by all threads of this state
 108 */
 109 typedef struct global_State {
 110   lua_Alloc frealloc;  /* function to reallocate memory */
 111   void *ud;         /* auxiliary data to 'frealloc' */
 112   l_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
 113   l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
 114   lu_mem GCmemtrav;  /* memory traversed by the GC */
 115   lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
 116   stringtable strt;  /* hash table for strings */
 117   TValue l_registry;
 118   unsigned int seed;  /* randomized seed for hashes */
 119   lu_byte currentwhite;
 120   lu_byte gcstate;  /* state of garbage collector */
 121   lu_byte gckind;  /* kind of GC running */
 122   lu_byte gcrunning;  /* true if GC is running */
 123   GCObject *allgc;  /* list of all collectable objects */
 124   GCObject **sweepgc;  /* current position of sweep in list */
 125   GCObject *finobj;  /* list of collectable objects with finalizers */
 126   GCObject *gray;  /* list of gray objects */
 127   GCObject *grayagain;  /* list of objects to be traversed atomically */
 128   GCObject *weak;  /* list of tables with weak values */
 129   GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
 130   GCObject *allweak;  /* list of all-weak tables */
 131   GCObject *tobefnz;  /* list of userdata to be GC */
 132   GCObject *fixedgc;  /* list of objects not to be collected */
 133   struct lua_State *twups;  /* list of threads with open upvalues */
 134   unsigned int gcfinnum;  /* number of finalizers to call in each GC step */
 135   int gcpause;  /* size of pause between successive GCs */
 136   int gcstepmul;  /* GC 'granularity' */
 137   lua_CFunction panic;  /* to be called in unprotected errors */
 138   struct lua_State *mainthread;
 139   const lua_Number *version;  /* pointer to version number */
 140   TString *memerrmsg;  /* memory-error message */
 141   TString *tmname[TM_N];  /* array with tag-method names */
 142   struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
 143   TString *strcache[STRCACHE_N][STRCACHE_M];  /* cache for strings in API */
 144 } global_State;
 145
 146
 147 /*
 148 ** 'per thread' state
 149 */
 150 struct lua_State {
 151   CommonHeader;
 152   unsigned short nci;  /* number of items in 'ci' list */
 153   lu_byte status;
 154   StkId top;  /* first free slot in the stack */
 155   global_State *l_G;
 156   CallInfo *ci;  /* call info for current function */
 157   const Instruction *oldpc;  /* last pc traced */
 158   StkId stack_last;  /* last free slot in the stack */
 159   StkId stack;  /* stack base */
 160   UpVal *openupval;  /* list of open upvalues in this stack */
 161   GCObject *gclist;
 162   struct lua_State *twups;  /* list of threads with open upvalues */
 163   struct lua_longjmp *errorJmp;  /* current error recover point */
 164   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
 165   lua_Hook hook;
 166   ptrdiff_t errfunc;  /* current error handling function (stack index) */
 167   int stacksize;
 168   int basehookcount;
 169   int hookcount;
 170   unsigned short nny;  /* number of non-yieldable calls in stack */
 171   unsigned short nCcalls;  /* number of nested C calls */
 172   lu_byte hookmask;
 173   lu_byte allowhook;
 174 };
 175
 176
 177 #define G(L)    (L->l_G)
 178
 179
 180 /*
 181 ** Union of all collectable objects (only for conversions)
 182 */
 183 union GCUnion {
 184   GCObject gc;  /* common header */
 185   struct TString ts;
 186   struct Udata u;
 187   union Closure cl;
 188   struct Table h;
 189   struct Proto p;
 190   struct lua_State th;  /* thread */
 191 };
 192
 193
 194 #define cast_u(o)       cast(union GCUnion *, (o))
 195
 196 /* macros to convert a GCObject into a specific value */
 197 #define gco2ts(o)  \
 198         check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
 199 #define gco2u(o)  check_exp((o)->tt == LUA_TUSERDATA, &((cast_u(o))->u))
 200 #define gco2lcl(o)  check_exp((o)->tt == LUA_TLCL, &((cast_u(o))->cl.l))
 201 #define gco2ccl(o)  check_exp((o)->tt == LUA_TCCL, &((cast_u(o))->cl.c))
 202 #define gco2cl(o)  \
 203         check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
 204 #define gco2t(o)  check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))
 205 #define gco2p(o)  check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p))
 206 #define gco2th(o)  check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th))
 207
 208
 209 /* macro to convert a Lua object into a GCObject */
 210 #define obj2gco(v) \
 211         check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc)))
 212
 213
 214 /* actual number of total bytes allocated */
 215 #define gettotalbytes(g)        cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
 216
 217 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
 218 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
 219 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
 220 LUAI_FUNC void luaE_freeCI (lua_State *L);
 221 LUAI_FUNC void luaE_shrinkCI (lua_State *L);
 222
 223
 224 #endif
 225