Lua 5.3.4 里的 lfunc.c

#ifndef lfunc_h
#define lfunc_h


#include "lobject.h"


#define sizeCclosure(n) (cast(int, sizeof(CClosure)) + \
                         cast(int, sizeof(TValue)*((n)-1)))

#define sizeLclosure(n) (cast(int, sizeof(LClosure)) + \
                         cast(int, sizeof(TValue *)*((n)-1)))


/* test whether thread is in 'twups' list */
#define isintwups(L)  (L->twups != L)


/*
** maximum number of upvalues in a closure (both C and Lua). (Value
** must fit in a VM register.)
*/
#define MAXUPVAL  255


/*
** Upvalues for Lua closures
*/
struct UpVal {
  TValue *v;  /* points to stack or to its own value */
  lu_mem refcount;  /* reference counter */
  union {
    struct {  /* (when open) */
      UpVal *next;  /* linked list */
      int touched;  /* mark to avoid cycles with dead threads */
    } open;
    TValue value;  /* the value (when closed) */
  } u;
};

#define upisopen(up)  ((up)->v != &(up)->u.value)


LUAI_FUNC Proto *luaF_newproto (lua_State *L);
LUAI_FUNC CClosure *luaF_newCclosure (lua_State *L, int nelems);
LUAI_FUNC LClosure *luaF_newLclosure (lua_State *L, int nelems);
LUAI_FUNC void luaF_initupvals (lua_State *L, LClosure *cl);
LUAI_FUNC UpVal *luaF_findupval (lua_State *L, StkId level);
LUAI_FUNC void luaF_close (lua_State *L, StkId level);
LUAI_FUNC void luaF_freeproto (lua_State *L, Proto *f);
LUAI_FUNC const char *luaF_getlocalname (const Proto *func, int local_number,
                                         int pc);


#endif

#define lfunc_c
#define LUA_CORE

#include "lprefix.h"


#include <stddef.h>

#include "lua.h"

#include "lfunc.h"
#include "lgc.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"



CClosure *luaF_newCclosure (lua_State *L, int n) {
  GCObject *o = luaC_newobj(L, LUA_TCCL, sizeCclosure(n));
  CClosure *c = gco2ccl(o);
  c->nupvalues = cast_byte(n);
  return c;
}


LClosure *luaF_newLclosure (lua_State *L, int n) {
  GCObject *o = luaC_newobj(L, LUA_TLCL, sizeLclosure(n));
  LClosure *c = gco2lcl(o);
  c->p = NULL;
  c->nupvalues = cast_byte(n);
  while (n--) c->upvals[n] = NULL;
  return c;
}

/*
** fill a closure with new closed upvalues
*/
void luaF_initupvals (lua_State *L, LClosure *cl) {
  int i;
  for (i = 0; i < cl->nupvalues; i++) {
    UpVal *uv = luaM_new(L, UpVal);
    uv->refcount = 1;
    uv->v = &uv->u.value;  /* make it closed */
    setnilvalue(uv->v);
    cl->upvals[i] = uv;
  }
}


UpVal *luaF_findupval (lua_State *L, StkId level) {
  UpVal **pp = &L->openupval;
  UpVal *p;
  UpVal *uv;
  lua_assert(isintwups(L) || L->openupval == NULL);
  while (*pp != NULL && (p = *pp)->v >= level) {
    lua_assert(upisopen(p));
    if (p->v == level)  /* found a corresponding upvalue? */
      return p;  /* return it */
    pp = &p->u.open.next;
  }
  /* not found: create a new upvalue */
  uv = luaM_new(L, UpVal);
  uv->refcount = 0;
  uv->u.open.next = *pp;  /* link it to list of open upvalues */
  uv->u.open.touched = 1;
  *pp = uv;
  uv->v = level;  /* current value lives in the stack */
  if (!isintwups(L)) {  /* thread not in list of threads with upvalues? */
    L->twups = G(L)->twups;  /* link it to the list */
    G(L)->twups = L;
  }
  return uv;
}


void luaF_close (lua_State *L, StkId level) {
  UpVal *uv;
  while (L->openupval != NULL && (uv = L->openupval)->v >= level) {
    lua_assert(upisopen(uv));
    L->openupval = uv->u.open.next;  /* remove from 'open' list */
    if (uv->refcount == 0)  /* no references? */
      luaM_free(L, uv);  /* free upvalue */
    else {
      setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
      uv->v = &uv->u.value;  /* now current value lives here */
      luaC_upvalbarrier(L, uv);
    }
  }
}


Proto *luaF_newproto (lua_State *L) {
  GCObject *o = luaC_newobj(L, LUA_TPROTO, sizeof(Proto));
  Proto *f = gco2p(o);
  f->k = NULL;
  f->sizek = 0;
  f->p = NULL;
  f->sizep = 0;
  f->code = NULL;
  f->cache = NULL;
  f->sizecode = 0;
  f->lineinfo = NULL;
  f->sizelineinfo = 0;
  f->upvalues = NULL;
  f->sizeupvalues = 0;
  f->numparams = 0;
  f->is_vararg = 0;
  f->maxstacksize = 0;
  f->locvars = NULL;
  f->sizelocvars = 0;
  f->linedefined = 0;
  f->lastlinedefined = 0;
  f->source = NULL;
  return f;
}


void luaF_freeproto (lua_State *L, Proto *f) {
  luaM_freearray(L, f->code, f->sizecode);
  luaM_freearray(L, f->p, f->sizep);
  luaM_freearray(L, f->k, f->sizek);
  luaM_freearray(L, f->lineinfo, f->sizelineinfo);
  luaM_freearray(L, f->locvars, f->sizelocvars);
  luaM_freearray(L, f->upvalues, f->sizeupvalues);
  luaM_free(L, f);
}


/*
** Look for n-th local variable at line 'line' in function 'func'.
** Returns NULL if not found.
*/
const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
  int i;
  for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
    if (pc < f->locvars[i].endpc) {  /* is variable active? */
      local_number--;
      if (local_number == 0)
        return getstr(f->locvars[i].varname);
    }
  }
  return NULL;  /* not found */
}