*init

1 files changed, 172 insertions, 0 deletions

diff --git a/lfunc.c b/lfunc.c
new file mode 100644
index 0000000..345af0b
--- /dev/null
+++ b/lfunc.c
@@ -0,0 +1,172 @@
+/*
+** $Id: lfunc.c,v 2.30.1.1 2013/04/12 18:48:47 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 n) {
+  Closure *c = &luaC_newobj(L, LUA_TCCL, sizeCclosure(n), NULL, 0)->cl;
+  c->c.nupvalues = cast_byte(n);
+  return c;
+}
+
+
+// saw 创建lua closure
+Closure *luaF_newLclosure (lua_State *L, int n) {
+  Closure *c = &luaC_newobj(L, LUA_TLCL, sizeLclosure(n), NULL, 0)->cl;
+  c->l.p = NULL;
+  c->l.nupvalues = cast_byte(n);
+  while (n--) c->l.upvals[n] = NULL;
+  return c;
+}
+
+
+// saw 创建upvalue结构，不是栈上变量关联的upvalue
+UpVal *luaF_newupval (lua_State *L) {
+  UpVal *uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), NULL, 0)->uv;
+  uv->v = &uv->u.value;
+  setnilvalue(uv->v);
+  return uv;
+}
+
+
+// saw 找到栈上变量对应的upvalue，如果么有的话创建一个并返回UpVal结构
+UpVal *luaF_findupval (lua_State *L, StkId level) {
+  global_State *g = G(L);
+  GCObject **pp = &L->openupval; // 没有退出栈的时候 upvalue链表
+  UpVal *p;
+  UpVal *uv;
+  while (*pp != NULL && (p = gco2uv(*pp))->v >= level) {
+    GCObject *o = obj2gco(p);
+    lua_assert(p->v != &p->u.value);
+    lua_assert(!isold(o) || isold(obj2gco(L)));
+    if (p->v == level) {  /* found a corresponding upvalue? */
+      if (isdead(g, o))  /* is it dead? */
+        changewhite(o);  /* resurrect it */
+      return p;
+    }
+    pp = &p->next;
+  }
+  /* not found: create a new one */
+  uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), pp, 0)->uv;
+  uv->v = level;  /* current value lives in the stack */
+  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;
+}
+
+
+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;
+}
+
+
+// saw 退出栈的时候将关联的upvalue关闭，从
+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 */
+}
+
+
+// saw 如果退出了栈，某些upvalue被闭包引用，需要close这些 upvalue:
+// 如果没有被引用，直接销毁
+// 如果被引用了，先从 L->openupval 中删除，
+void luaF_close (lua_State *L, StkId level) {
+  UpVal *uv;
+  global_State *g = G(L);
+  while (L->openupval != NULL && (uv = gco2uv(L->openupval))->v >= level) {
+    GCObject *o = obj2gco(uv);
+    lua_assert(!isblack(o) && uv->v != &uv->u.value);
+    L->openupval = uv->next;  /* remove from `open' list */
+    if (isdead(g, o))
+      luaF_freeupval(L, uv);  /* free upvalue */ // 没有被引用的话直接释放
+    else {
+			// 先将upvalue从L->openupval中移除，给下面用
+      unlinkupval(uv);  /* remove upvalue from 'uvhead' list */
+			// 移动栈里面保存的值
+      setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
+			// 修改pointer指到自己的值的地址
+      uv->v = &uv->u.value;  /* now current value lives here */
+      gch(o)->next = g->allgc;  /* link upvalue into 'allgc' list */
+      g->allgc = o;
+      luaC_checkupvalcolor(g, uv);
+    }
+  }
+}
+
+
+Proto *luaF_newproto (lua_State *L) {
+  Proto *f = &luaC_newobj(L, LUA_TPROTO, sizeof(Proto), NULL, 0)->p;
+  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;
+}
+
+
+// saw 释放函数原型
+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 */
+}
+