From 77ac95b9985f5669d6659bfb54728786d28c2ef0 Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Mon, 20 Jul 2020 09:42:30 +0800
Subject: *misc

---
 src/lua51/lstate.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 6 deletions(-)

(limited to 'src/lua51/lstate.h')

diff --git a/src/lua51/lstate.h b/src/lua51/lstate.h
index 3bc575b..1ec30a8 100644
--- a/src/lua51/lstate.h
+++ b/src/lua51/lstate.h
@@ -35,20 +35,31 @@ struct lua_longjmp;  /* defined in ldo.c */
 
 
 
+//c 散列桶
+//c 全局存放字符串的地方。如果一个字符串在此存在，不用重新生成。
+//c 如果表扩张的太厉害，每个桶的字符串太多，会进行一次rehash，重新分配每个桶的数据量
+//c rehash在lstring.c -> luaS_resize
 typedef struct stringtable {
-  GCObject **hash;
-  lu_int32 nuse;  /* number of elements */
-  int size;
+  GCObject **hash; //c 字符串，因为是散列桶，所以是**
+  lu_int32 nuse;  //c 桶用到的容量，因为不一定size都用到了 /* number of elements */
+  int size; //c 桶的总容量，是常值
+	// nuse和size是用来动态控制桶容量的关键
 } stringtable;
 
 
+//c 当前函数的调用信息，和lua_State的调用部分类似
+//c 都有top, base俩个与栈相关的成员
+//c StkId引用的永远是lua_State栈上的内容
 /*
 ** informations about a call
 */
 typedef struct CallInfo {
+	//c 当前调用的base值，即在栈上操作的开始位置
   StkId base;  /* base for this function */
+	//c 函数原型在lua_State数据栈上的位置
   StkId func;  /* function index in the stack */
   StkId	top;  /* top for this function */
+	//c 当前执行到的指令位置
   const Instruction *savedpc;
   int nresults;  /* expected number of results from this function */
   int tailcalls;  /* number of tail calls lost under this entry */
@@ -61,31 +72,46 @@ typedef struct CallInfo {
 #define f_isLua(ci)	(!ci_func(ci)->c.isC)
 #define isLua(ci)	(ttisfunction((ci)->func) && f_isLua(ci))
 
-
+//c 当前虚拟机所有协程共用的内容
 /*
 ** `global state', shared by all threads of this state
 */
 typedef struct global_State {
+	//c string table,开散列表，存储所有的字符串
   stringtable strt;  /* hash table for strings */
   lua_Alloc frealloc;  /* function to reallocate memory */
   void *ud;         /* auxiliary data to `frealloc' */
-  lu_byte currentwhite;
+  lu_byte currentwhite;//当前白
+	//c 当前的GC状态，有5个，在lgc.h定义
   lu_byte gcstate;  /* state of garbage collector */
+	//c strt中字符串散列桶索引，字符串回收阶段每次回收一个散列桶的字符串，
   int sweepstrgc;  /* position of sweep in `strt' */
+	//c 白色链表。可回收的对象，会在回收阶段被回收
+	//c 所有新建的对象都会暂存在这里，但不会被回收，因为lua有双白色机制
   GCObject *rootgc;  /* list of all collectable objects */
+	//c 保存rootgc中当前回收到的位置，下次从这个位置继续回收
   GCObject **sweepgc;  /* position of sweep in `rootgc' */
+	//c 灰色链表
   GCObject *gray;  /* list of gray objects */
+	//c 不可被打断的对象的灰色链表
   GCObject *grayagain;  /* list of objects to be traversed atomically */
+	//c 弱表
   GCObject *weak;  /* list of weak tables (to be cleared) */
+	//c 有__gc方法的userdata
   GCObject *tmudata;  /* last element of list of userdata to be GC */
   Mbuffer buff;  /* temporary buffer for string concatentation */
   lu_mem GCthreshold;
+	//c 开始进行GC的阈值，当超过这个值时开始GC
   lu_mem totalbytes;  /* number of bytes currently allocated */
+	//c 内存大小的估计值
   lu_mem estimate;  /* an estimate of number of bytes actually in use */
   lu_mem gcdept;  /* how much GC is `behind schedule' */
+	//c 控制下一轮GC开始时机
   int gcpause;  /* size of pause between successive GCs */
+	//c 控制GC回收速度
   int gcstepmul;  /* GC `granularity' */
   lua_CFunction panic;  /* to be called in unprotected errors */
+	//c 注册表
   TValue l_registry;
   struct lua_State *mainthread;
   UpVal uvhead;  /* head of double-linked list of all open upvalues */
@@ -94,20 +120,29 @@ typedef struct global_State {
 } global_State;
 
 
+//c 一个lua_state，可以看做是一个
+//c StkId引用的永远是lua_State栈上的内容
 /*
 ** `per thread' state
 */
 struct lua_State {
   CommonHeader;
   lu_byte status;
+	//c 当前栈的下一个可用位置
   StkId top;  /* first free slot in the stack */
+	//c 当前*函数栈*的基地址，给某个函数用，在luad_precall函数中设置L->base = ci->base = ci->func + 1;
   StkId base;  /* base of current function */
   global_State *l_G;
+	//c 当前函数的调用信息，是base_ci数组中的某个
   CallInfo *ci;  /* call info for current function */
   const Instruction *savedpc;  /* `savedpc' of current function */
+	//c lua_State数据栈的终点
   StkId stack_last;  /* last free slot in the stack */
+	//c 数据栈(栈数组的起始地址)（数据栈的起始点）
   StkId stack;  /* stack base */
+	//c callinfo数组的终点
   CallInfo *end_ci;  /* points after end of ci array*/
+	//c callinfo 数组， 沿着base_ci遍历可以得到完整的lua调用链
   CallInfo *base_ci;  /* array of CallInfo's */
   int stacksize;
   int size_ci;  /* size of array `base_ci' */
@@ -118,6 +153,7 @@ struct lua_State {
   int basehookcount;
   int hookcount;
   lua_Hook hook;
+	//c _G global table
   TValue l_gt;  /* table of globals */
   TValue env;  /* temporary place for environments */
   GCObject *openupval;  /* list of open upvalues in this stack */
@@ -130,6 +166,10 @@ struct lua_State {
 #define G(L)	(L->l_G)
 
 
+//c 需要GC的类型基类，通过GCObject能够引用到GCheader中定义的/
+//c #define CommonHeader	GCObject *next; lu_byte tt; lu_byte marked
+//c 这种写法是一种实现C继承的方式
+//c 每个
 /*
 ** Union of all collectable objects
 */
@@ -144,7 +184,7 @@ union GCObject {
   struct lua_State th;  /* thread */
 };
 
-
+//c TValue\GCObject 获取union中的内容
 /* macros to convert a GCObject into a specific value */
 #define rawgco2ts(o)	check_exp((o)->gch.tt == LUA_TSTRING, &((o)->ts))
 #define gco2ts(o)	(&rawgco2ts(o)->tsv)
-- 
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