nanocoat/lib/3rdparty/lua/lfunc.c

   1 /*
   2 ** $Id: lfunc.c $
   3 ** Auxiliary functions to manipulate prototypes and closures
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #define lfunc_c
   8 #define LUA_CORE
   9
  10 #include "lprefix.h"
  11
  12
  13 #include <stddef.h>
  14
  15 #include "lua.h"
  16
  17 #include "ldebug.h"
  18 #include "ldo.h"
  19 #include "lfunc.h"
  20 #include "lgc.h"
  21 #include "lmem.h"
  22 #include "lobject.h"
  23 #include "lstate.h"
  24
  25
  26
  27 CClosure *luaF_newCclosure (lua_State *L, int nupvals) {
  28   GCObject *o = luaC_newobj(L, LUA_VCCL, sizeCclosure(nupvals));
  29   CClosure *c = gco2ccl(o);
  30   c->nupvalues = cast_byte(nupvals);
  31   return c;
  32 }
  33
  34
  35 LClosure *luaF_newLclosure (lua_State *L, int nupvals) {
  36   GCObject *o = luaC_newobj(L, LUA_VLCL, sizeLclosure(nupvals));
  37   LClosure *c = gco2lcl(o);
  38   c->p = NULL;
  39   c->nupvalues = cast_byte(nupvals);
  40   while (nupvals--) c->upvals[nupvals] = NULL;
  41   return c;
  42 }
  43
  44
  45 /*
  46 ** fill a closure with new closed upvalues
  47 */
  48 void luaF_initupvals (lua_State *L, LClosure *cl) {
  49   int i;
  50   for (i = 0; i < cl->nupvalues; i++) {
  51     GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
  52     UpVal *uv = gco2upv(o);
  53     uv->v.p = &uv->u.value;  /* make it closed */
  54     setnilvalue(uv->v.p);
  55     cl->upvals[i] = uv;
  56     luaC_objbarrier(L, cl, uv);
  57   }
  58 }
  59
  60
  61 /*
  62 ** Create a new upvalue at the given level, and link it to the list of
  63 ** open upvalues of 'L' after entry 'prev'.
  64 **/
  65 static UpVal *newupval (lua_State *L, StkId level, UpVal **prev) {
  66   GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
  67   UpVal *uv = gco2upv(o);
  68   UpVal *next = *prev;
  69   uv->v.p = s2v(level);  /* current value lives in the stack */
  70   uv->u.open.next = next;  /* link it to list of open upvalues */
  71   uv->u.open.previous = prev;
  72   if (next)
  73     next->u.open.previous = &uv->u.open.next;
  74   *prev = uv;
  75   if (!isintwups(L)) {  /* thread not in list of threads with upvalues? */
  76     L->twups = G(L)->twups;  /* link it to the list */
  77     G(L)->twups = L;
  78   }
  79   return uv;
  80 }
  81
  82
  83 /*
  84 ** Find and reuse, or create if it does not exist, an upvalue
  85 ** at the given level.
  86 */
  87 UpVal *luaF_findupval (lua_State *L, StkId level) {
  88   UpVal **pp = &L->openupval;
  89   UpVal *p;
  90   lua_assert(isintwups(L) || L->openupval == NULL);
  91   while ((p = *pp) != NULL && uplevel(p) >= level) {  /* search for it */
  92     lua_assert(!isdead(G(L), p));
  93     if (uplevel(p) == level)  /* corresponding upvalue? */
  94       return p;  /* return it */
  95     pp = &p->u.open.next;
  96   }
  97   /* not found: create a new upvalue after 'pp' */
  98   return newupval(L, level, pp);
  99 }
 100
 101
 102 /*
 103 ** Call closing method for object 'obj' with error message 'err'. The
 104 ** boolean 'yy' controls whether the call is yieldable.
 105 ** (This function assumes EXTRA_STACK.)
 106 */
 107 static void callclosemethod (lua_State *L, TValue *obj, TValue *err, int yy) {
 108   StkId top = L->top.p;
 109   const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
 110   setobj2s(L, top, tm);  /* will call metamethod... */
 111   setobj2s(L, top + 1, obj);  /* with 'self' as the 1st argument */
 112   setobj2s(L, top + 2, err);  /* and error msg. as 2nd argument */
 113   L->top.p = top + 3;  /* add function and arguments */
 114   if (yy)
 115     luaD_call(L, top, 0);
 116   else
 117     luaD_callnoyield(L, top, 0);
 118 }
 119
 120
 121 /*
 122 ** Check whether object at given level has a close metamethod and raise
 123 ** an error if not.
 124 */
 125 static void checkclosemth (lua_State *L, StkId level) {
 126   const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
 127   if (ttisnil(tm)) {  /* no metamethod? */
 128     int idx = cast_int(level - L->ci->func.p);  /* variable index */
 129     const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
 130     if (vname == NULL) vname = "?";
 131     luaG_runerror(L, "variable '%s' got a non-closable value", vname);
 132   }
 133 }
 134
 135
 136 /*
 137 ** Prepare and call a closing method.
 138 ** If status is CLOSEKTOP, the call to the closing method will be pushed
 139 ** at the top of the stack. Otherwise, values can be pushed right after
 140 ** the 'level' of the upvalue being closed, as everything after that
 141 ** won't be used again.
 142 */
 143 static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
 144   TValue *uv = s2v(level);  /* value being closed */
 145   TValue *errobj;
 146   if (status == CLOSEKTOP)
 147     errobj = &G(L)->nilvalue;  /* error object is nil */
 148   else {  /* 'luaD_seterrorobj' will set top to level + 2 */
 149     errobj = s2v(level + 1);  /* error object goes after 'uv' */
 150     luaD_seterrorobj(L, status, level + 1);  /* set error object */
 151   }
 152   callclosemethod(L, uv, errobj, yy);
 153 }
 154
 155
 156 /*
 157 ** Maximum value for deltas in 'tbclist', dependent on the type
 158 ** of delta. (This macro assumes that an 'L' is in scope where it
 159 ** is used.)
 160 */
 161 #define MAXDELTA  \
 162         ((256ul << ((sizeof(L->stack.p->tbclist.delta) - 1) * 8)) - 1)
 163
 164
 165 /*
 166 ** Insert a variable in the list of to-be-closed variables.
 167 */
 168 void luaF_newtbcupval (lua_State *L, StkId level) {
 169   lua_assert(level > L->tbclist.p);
 170   if (l_isfalse(s2v(level)))
 171     return;  /* false doesn't need to be closed */
 172   checkclosemth(L, level);  /* value must have a close method */
 173   while (cast_uint(level - L->tbclist.p) > MAXDELTA) {
 174     L->tbclist.p += MAXDELTA;  /* create a dummy node at maximum delta */
 175     L->tbclist.p->tbclist.delta = 0;
 176   }
 177   level->tbclist.delta = cast(unsigned short, level - L->tbclist.p);
 178   L->tbclist.p = level;
 179 }
 180
 181
 182 void luaF_unlinkupval (UpVal *uv) {
 183   lua_assert(upisopen(uv));
 184   *uv->u.open.previous = uv->u.open.next;
 185   if (uv->u.open.next)
 186     uv->u.open.next->u.open.previous = uv->u.open.previous;
 187 }
 188
 189
 190 /*
 191 ** Close all upvalues up to the given stack level.
 192 */
 193 void luaF_closeupval (lua_State *L, StkId level) {
 194   UpVal *uv;
 195   StkId upl;  /* stack index pointed by 'uv' */
 196   while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
 197     TValue *slot = &uv->u.value;  /* new position for value */
 198     lua_assert(uplevel(uv) < L->top.p);
 199     luaF_unlinkupval(uv);  /* remove upvalue from 'openupval' list */
 200     setobj(L, slot, uv->v.p);  /* move value to upvalue slot */
 201     uv->v.p = slot;  /* now current value lives here */
 202     if (!iswhite(uv)) {  /* neither white nor dead? */
 203       nw2black(uv);  /* closed upvalues cannot be gray */
 204       luaC_barrier(L, uv, slot);
 205     }
 206   }
 207 }
 208
 209
 210 /*
 211 ** Remove first element from the tbclist plus its dummy nodes.
 212 */
 213 static void poptbclist (lua_State *L) {
 214   StkId tbc = L->tbclist.p;
 215   lua_assert(tbc->tbclist.delta > 0);  /* first element cannot be dummy */
 216   tbc -= tbc->tbclist.delta;
 217   while (tbc > L->stack.p && tbc->tbclist.delta == 0)
 218     tbc -= MAXDELTA;  /* remove dummy nodes */
 219   L->tbclist.p = tbc;
 220 }
 221
 222
 223 /*
 224 ** Close all upvalues and to-be-closed variables up to the given stack
 225 ** level. Return restored 'level'.
 226 */
 227 StkId luaF_close (lua_State *L, StkId level, int status, int yy) {
 228   ptrdiff_t levelrel = savestack(L, level);
 229   luaF_closeupval(L, level);  /* first, close the upvalues */
 230   while (L->tbclist.p >= level) {  /* traverse tbc's down to that level */
 231     StkId tbc = L->tbclist.p;  /* get variable index */
 232     poptbclist(L);  /* remove it from list */
 233     prepcallclosemth(L, tbc, status, yy);  /* close variable */
 234     level = restorestack(L, levelrel);
 235   }
 236   return level;
 237 }
 238
 239
 240 Proto *luaF_newproto (lua_State *L) {
 241   GCObject *o = luaC_newobj(L, LUA_VPROTO, sizeof(Proto));
 242   Proto *f = gco2p(o);
 243   f->k = NULL;
 244   f->sizek = 0;
 245   f->p = NULL;
 246   f->sizep = 0;
 247   f->code = NULL;
 248   f->sizecode = 0;
 249   f->lineinfo = NULL;
 250   f->sizelineinfo = 0;
 251   f->abslineinfo = NULL;
 252   f->sizeabslineinfo = 0;
 253   f->upvalues = NULL;
 254   f->sizeupvalues = 0;
 255   f->numparams = 0;
 256   f->is_vararg = 0;
 257   f->maxstacksize = 0;
 258   f->locvars = NULL;
 259   f->sizelocvars = 0;
 260   f->linedefined = 0;
 261   f->lastlinedefined = 0;
 262   f->source = NULL;
 263   return f;
 264 }
 265
 266
 267 void luaF_freeproto (lua_State *L, Proto *f) {
 268   luaM_freearray(L, f->code, f->sizecode);
 269   luaM_freearray(L, f->p, f->sizep);
 270   luaM_freearray(L, f->k, f->sizek);
 271   luaM_freearray(L, f->lineinfo, f->sizelineinfo);
 272   luaM_freearray(L, f->abslineinfo, f->sizeabslineinfo);
 273   luaM_freearray(L, f->locvars, f->sizelocvars);
 274   luaM_freearray(L, f->upvalues, f->sizeupvalues);
 275   luaM_free(L, f);
 276 }
 277
 278
 279 /*
 280 ** Look for n-th local variable at line 'line' in function 'func'.
 281 ** Returns NULL if not found.
 282 */
 283 const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
 284   int i;
 285   for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
 286     if (pc < f->locvars[i].endpc) {  /* is variable active? */
 287       local_number--;
 288       if (local_number == 0)
 289         return getstr(f->locvars[i].varname);
 290     }
 291   }
 292   return NULL;  /* not found */
 293 }
 294