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/*
** $Id: lfunc.c,v 2.12.1.2 2007/12/28 14:58:43 roberto Exp $
** Auxiliary functions to manipulate prototypes and closures
** See Copyright Notice in lua.h
*/
#include <stddef.h>
#define lfunc_c
#define LUA_CORE
#include "lua.h"
#include "lfunc.h"
#include "lgc.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e) {
Closure *c = cast(Closure *, luaM_malloc(L, sizeCclosure(nelems)));
luaC_link(L, obj2gco(c), LUA_TFUNCTION);
c->c.isC = 1;
c->c.env = e;
c->c.nupvalues = cast_byte(nelems);
return c;
}
//c 新建lua closure
//c nelems upvalue的个数
//c 这个方法有两个地方调用，一个是f_parser，在代码编译后生成一个闭包；一个是闭包内嵌方法执行到OP_CLOSURE指令时新建闭包
Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {
Closure *c = cast(Closure *, luaM_malloc(L, sizeLclosure(nelems)));
luaC_link(L, obj2gco(c), LUA_TFUNCTION); //c 加入GC链表
c->l.isC = 0; //c not c closure
c->l.env = e; //c 设置这个闭包的环境表
c->l.nupvalues = cast_byte(nelems);
while (nelems--) c->l.upvals[nelems] = NULL;
return c;
}
//c 新建一个upvalue，默认是closed
UpVal *luaF_newupval (lua_State *L) {
UpVal *uv = luaM_new(L, UpVal);
luaC_link(L, obj2gco(uv), LUA_TUPVAL); //c 加入GC链表
uv->v = &uv->u.value; //c closed
setnilvalue(uv->v);
return uv;
}
//c 设置upvalue的数据指针指向stack中某个值level
UpVal *luaF_findupval (lua_State *L, StkId level) {
global_State *g = G(L);
GCObject **pp = &L->openupval;
UpVal *p;
UpVal *uv;
while (*pp != NULL && (p = ngcotouv(*pp))->v >= level) {
lua_assert(p->v != &p->u.value);
if (p->v == level) { /* found a corresponding upvalue? */
if (isdead(g, obj2gco(p))) /* is it dead? */
changewhite(obj2gco(p)); /* ressurect it */
return p;
}
pp = &p->next;
}
uv = luaM_new(L, UpVal); /* not found: create a new one */
uv->tt = LUA_TUPVAL;
uv->marked = luaC_white(g);
uv->v = level; /* current value lives in the stack */
uv->next = *pp; /* chain it in the proper position */
*pp = obj2gco(uv);
uv->u.l.prev = &g->uvhead; /* double link it in `uvhead' list */
uv->u.l.next = g->uvhead.u.l.next;
uv->u.l.next->u.l.prev = uv;
g->uvhead.u.l.next = uv;
lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
return uv;
}
// 把uv从global_state->uvhead或者lua_state->openupval中删除
static void unlinkupval (UpVal *uv) {
lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
uv->u.l.next->u.l.prev = uv->u.l.prev; /* remove from `uvhead' list */
uv->u.l.prev->u.l.next = uv->u.l.next;
}
//c 从global_state->uvhead中删除并释放内存
void luaF_freeupval (lua_State *L, UpVal *uv) {
if (uv->v != &uv->u.value) /* is it open? */
unlinkupval(uv); /* remove from open list */
luaM_free(L, uv); /* free upvalue */
}
//c 设置闭包的upvalue
void luaF_close (lua_State *L, StkId level) {
log("luaF_close()");
UpVal *uv;
global_State *g = G(L);
while (L->openupval != NULL && (uv = ngcotouv(L->openupval))->v >= level) {
GCObject *o = obj2gco(uv);
lua_assert(!isblack(o) && uv->v != &uv->u.value); //必须是 open upvalue
L->openupval = uv->next; /* remove from `open' list */
if (isdead(g, o))
luaF_freeupval(L, uv); /* free upvalue */
else {
unlinkupval(uv); // 从L->openupval中删除
setobj(L, &uv->u.value, uv->v); // 拷贝到upvalue的value字段，upvalue储存值
uv->v = &uv->u.value; /* now current value lives here */
luaC_linkupval(L, uv); /* link upvalue into `gcroot' list */
}
}
}
Proto *luaF_newproto (lua_State *L) {
Proto *f = luaM_new(L, Proto);
luaC_link(L, obj2gco(f), LUA_TPROTO);
f->k = NULL;
f->sizek = 0;
f->p = NULL;
f->sizep = 0;
f->code = NULL;
f->sizecode = 0;
f->sizelineinfo = 0;
f->sizeupvalues = 0;
f->nups = 0;
f->upvalues = NULL;
f->numparams = 0;
f->is_vararg = 0;
f->maxstacksize = 0;
f->lineinfo = NULL;
f->sizelocvars = 0;
f->locvars = NULL;
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, Instruction);
luaM_freearray(L, f->p, f->sizep, Proto *);
luaM_freearray(L, f->k, f->sizek, TValue);
luaM_freearray(L, f->lineinfo, f->sizelineinfo, int);
luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
luaM_free(L, f);
}
void luaF_freeclosure (lua_State *L, Closure *c) {
int size = (c->c.isC) ? sizeCclosure(c->c.nupvalues) :
sizeLclosure(c->l.nupvalues);
luaM_freemem(L, c, size);
}
/*
** 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 */
}
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