mudgangster

Tiny, scriptable MUD client
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lstate.h (8743B)


      1 /*
      2 ** $Id: lstate.h,v 2.133.1.1 2017/04/19 17:39:34 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 ** Moreover, there is another set of lists that control gray objects.
     31 ** These lists are linked by fields 'gclist'. (All objects that
     32 ** can become gray have such a field. The field is not the same
     33 ** in all objects, but it always has this name.)  Any gray object
     34 ** must belong to one of these lists, and all objects in these lists
     35 ** must be gray:
     36 **
     37 ** 'gray': regular gray objects, still waiting to be visited.
     38 ** 'grayagain': objects that must be revisited at the atomic phase.
     39 **   That includes
     40 **   - black objects got in a write barrier;
     41 **   - all kinds of weak tables during propagation phase;
     42 **   - all threads.
     43 ** 'weak': tables with weak values to be cleared;
     44 ** 'ephemeron': ephemeron tables with white->white entries;
     45 ** 'allweak': tables with weak keys and/or weak values to be cleared.
     46 ** The last three lists are used only during the atomic phase.
     47 
     48 */
     49 
     50 
     51 struct lua_longjmp;  /* defined in ldo.c */
     52 
     53 
     54 /*
     55 ** Atomic type (relative to signals) to better ensure that 'lua_sethook'
     56 ** is thread safe
     57 */
     58 #if !defined(l_signalT)
     59 #include <signal.h>
     60 #define l_signalT	sig_atomic_t
     61 #endif
     62 
     63 
     64 /* extra stack space to handle TM calls and some other extras */
     65 #define EXTRA_STACK   5
     66 
     67 
     68 #define BASIC_STACK_SIZE        (2*LUA_MINSTACK)
     69 
     70 
     71 /* kinds of Garbage Collection */
     72 #define KGC_NORMAL	0
     73 #define KGC_EMERGENCY	1	/* gc was forced by an allocation failure */
     74 
     75 
     76 typedef struct stringtable {
     77   TString **hash;
     78   int nuse;  /* number of elements */
     79   int size;
     80 } stringtable;
     81 
     82 
     83 /*
     84 ** Information about a call.
     85 ** When a thread yields, 'func' is adjusted to pretend that the
     86 ** top function has only the yielded values in its stack; in that
     87 ** case, the actual 'func' value is saved in field 'extra'.
     88 ** When a function calls another with a continuation, 'extra' keeps
     89 ** the function index so that, in case of errors, the continuation
     90 ** function can be called with the correct top.
     91 */
     92 typedef struct CallInfo {
     93   StkId func;  /* function index in the stack */
     94   StkId	top;  /* top for this function */
     95   struct CallInfo *previous, *next;  /* dynamic call link */
     96   union {
     97     struct {  /* only for Lua functions */
     98       StkId base;  /* base for this function */
     99       const Instruction *savedpc;
    100     } l;
    101     struct {  /* only for C functions */
    102       lua_KFunction k;  /* continuation in case of yields */
    103       ptrdiff_t old_errfunc;
    104       lua_KContext ctx;  /* context info. in case of yields */
    105     } c;
    106   } u;
    107   ptrdiff_t extra;
    108   short nresults;  /* expected number of results from this function */
    109   unsigned short callstatus;
    110 } CallInfo;
    111 
    112 
    113 /*
    114 ** Bits in CallInfo status
    115 */
    116 #define CIST_OAH	(1<<0)	/* original value of 'allowhook' */
    117 #define CIST_LUA	(1<<1)	/* call is running a Lua function */
    118 #define CIST_HOOKED	(1<<2)	/* call is running a debug hook */
    119 #define CIST_FRESH	(1<<3)	/* call is running on a fresh invocation
    120                                    of luaV_execute */
    121 #define CIST_YPCALL	(1<<4)	/* call is a yieldable protected call */
    122 #define CIST_TAIL	(1<<5)	/* call was tail called */
    123 #define CIST_HOOKYIELD	(1<<6)	/* last hook called yielded */
    124 #define CIST_LEQ	(1<<7)  /* using __lt for __le */
    125 #define CIST_FIN	(1<<8)  /* call is running a finalizer */
    126 
    127 #define isLua(ci)	((ci)->callstatus & CIST_LUA)
    128 
    129 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */
    130 #define setoah(st,v)	((st) = ((st) & ~CIST_OAH) | (v))
    131 #define getoah(st)	((st) & CIST_OAH)
    132 
    133 
    134 /*
    135 ** 'global state', shared by all threads of this state
    136 */
    137 typedef struct global_State {
    138   lua_Alloc frealloc;  /* function to reallocate memory */
    139   void *ud;         /* auxiliary data to 'frealloc' */
    140   l_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
    141   l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
    142   lu_mem GCmemtrav;  /* memory traversed by the GC */
    143   lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
    144   stringtable strt;  /* hash table for strings */
    145   TValue l_registry;
    146   unsigned int seed;  /* randomized seed for hashes */
    147   lu_byte currentwhite;
    148   lu_byte gcstate;  /* state of garbage collector */
    149   lu_byte gckind;  /* kind of GC running */
    150   lu_byte gcrunning;  /* true if GC is running */
    151   GCObject *allgc;  /* list of all collectable objects */
    152   GCObject **sweepgc;  /* current position of sweep in list */
    153   GCObject *finobj;  /* list of collectable objects with finalizers */
    154   GCObject *gray;  /* list of gray objects */
    155   GCObject *grayagain;  /* list of objects to be traversed atomically */
    156   GCObject *weak;  /* list of tables with weak values */
    157   GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
    158   GCObject *allweak;  /* list of all-weak tables */
    159   GCObject *tobefnz;  /* list of userdata to be GC */
    160   GCObject *fixedgc;  /* list of objects not to be collected */
    161   struct lua_State *twups;  /* list of threads with open upvalues */
    162   unsigned int gcfinnum;  /* number of finalizers to call in each GC step */
    163   int gcpause;  /* size of pause between successive GCs */
    164   int gcstepmul;  /* GC 'granularity' */
    165   lua_CFunction panic;  /* to be called in unprotected errors */
    166   struct lua_State *mainthread;
    167   const lua_Number *version;  /* pointer to version number */
    168   TString *memerrmsg;  /* memory-error message */
    169   TString *tmname[TM_N];  /* array with tag-method names */
    170   struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
    171   TString *strcache[STRCACHE_N][STRCACHE_M];  /* cache for strings in API */
    172 } global_State;
    173 
    174 
    175 /*
    176 ** 'per thread' state
    177 */
    178 struct lua_State {
    179   CommonHeader;
    180   unsigned short nci;  /* number of items in 'ci' list */
    181   lu_byte status;
    182   StkId top;  /* first free slot in the stack */
    183   global_State *l_G;
    184   CallInfo *ci;  /* call info for current function */
    185   const Instruction *oldpc;  /* last pc traced */
    186   StkId stack_last;  /* last free slot in the stack */
    187   StkId stack;  /* stack base */
    188   UpVal *openupval;  /* list of open upvalues in this stack */
    189   GCObject *gclist;
    190   struct lua_State *twups;  /* list of threads with open upvalues */
    191   struct lua_longjmp *errorJmp;  /* current error recover point */
    192   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
    193   volatile lua_Hook hook;
    194   ptrdiff_t errfunc;  /* current error handling function (stack index) */
    195   int stacksize;
    196   int basehookcount;
    197   int hookcount;
    198   unsigned short nny;  /* number of non-yieldable calls in stack */
    199   unsigned short nCcalls;  /* number of nested C calls */
    200   l_signalT hookmask;
    201   lu_byte allowhook;
    202 };
    203 
    204 
    205 #define G(L)	(L->l_G)
    206 
    207 
    208 /*
    209 ** Union of all collectable objects (only for conversions)
    210 */
    211 union GCUnion {
    212   GCObject gc;  /* common header */
    213   struct TString ts;
    214   struct Udata u;
    215   union Closure cl;
    216   struct Table h;
    217   struct Proto p;
    218   struct lua_State th;  /* thread */
    219 };
    220 
    221 
    222 #define cast_u(o)	cast(union GCUnion *, (o))
    223 
    224 /* macros to convert a GCObject into a specific value */
    225 #define gco2ts(o)  \
    226 	check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
    227 #define gco2u(o)  check_exp((o)->tt == LUA_TUSERDATA, &((cast_u(o))->u))
    228 #define gco2lcl(o)  check_exp((o)->tt == LUA_TLCL, &((cast_u(o))->cl.l))
    229 #define gco2ccl(o)  check_exp((o)->tt == LUA_TCCL, &((cast_u(o))->cl.c))
    230 #define gco2cl(o)  \
    231 	check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
    232 #define gco2t(o)  check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))
    233 #define gco2p(o)  check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p))
    234 #define gco2th(o)  check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th))
    235 
    236 
    237 /* macro to convert a Lua object into a GCObject */
    238 #define obj2gco(v) \
    239 	check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc)))
    240 
    241 
    242 /* actual number of total bytes allocated */
    243 #define gettotalbytes(g)	cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
    244 
    245 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
    246 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
    247 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
    248 LUAI_FUNC void luaE_freeCI (lua_State *L);
    249 LUAI_FUNC void luaE_shrinkCI (lua_State *L);
    250 
    251 
    252 #endif
    253