lua5.3.3源码学习日志（1）--lstate.h

中文记录

可能，会很零碎，看到哪，写到哪。顺便学习markdown，不定期，慢慢更新。

1. 一些关于gc对象的话，所有的对象objects在lua里面再被释放前，都应该有方法可以访问到。所以，所有的objects总是属于某个（也是唯一一个）列表，通过next字段来链接。

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关键字

• stringtable

 typedef struct stringtable {        TString **hash;        int nuse;  /* number of elements */        int size;    } stringtable;

• CallInfo

/*** Information about a call.** When a thread yields, 'func' is adjusted to pretend that the** top function has only the yielded values in its stack; in that** case, the actual 'func' value is saved in field 'extra'. ** When a function calls another with a continuation, 'extra' keeps** the function index so that, in case of errors, the continuation** function can be called with the correct top.*/typedef struct CallInfo {  StkId func;  /* function index in the stack */  StkId top;  /* top for this function */  struct CallInfo *previous, *next;  /* dynamic call link */  union {    struct {  /* only for Lua functions */      StkId base;  /* base for this function */      const Instruction *savedpc;    } l;    struct {  /* only for C functions */      lua_KFunction k;  /* continuation in case of yields */      ptrdiff_t old_errfunc;      lua_KContext ctx;  /* context info. in case of yields */    } c;  } u;  ptrdiff_t extra;  short nresults;  /* expected number of results from this function */  lu_byte callstatus;} CallInfo;

• 这里我理解为，当调用在某个thread上的时候（yields），func 会被调整成一个顶层函数，在堆栈里拥有着唯一的值。emmmm，还是要去看实现调用。

• callstatus，类型是 lu_byte（unsigned char），主要用于通过位与确定回调（call）的状态,类型如下：

/*** Bits in CallInfo status*/#define CIST_OAH    (1<<0)  /* original value of 'allowhook' */#define CIST_LUA    (1<<1)  /* call is running a Lua function */#define CIST_HOOKED (1<<2)  /* call is running a debug hook */#define CIST_FRESH  (1<<3)  /* call is running on a fresh invocationof luaV_execute */#define CIST_YPCALL (1<<4)  /* call is a yieldable protected call */#define CIST_TAIL   (1<<5)  /* call was tail called */#define CIST_HOOKYIELD  (1<<6)  /* last hook called yielded */#define CIST_LEQ    (1<<7)  /* using __lt for __le */

• 基础设置函数：设置callstatus

/* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */#define setoah(st,v)    ((st) = ((st) & ~CIST_OAH) | (v))#define getoah(st)  ((st) & CIST_OAH)

• global_State

/*** 'global state', shared by all threads of this state*/typedef struct global_State{···}

• lua_State ，

/*** 'per thread' state*/struct lua_State {CommonHeader;···}

• CommonHeader , 就通用头，所有可回收的objects。

/*** Common Header for all collectable objects (in macro form, to be** included in other objects)*/#define CommonHeader    GCObject *next; lu_byte tt; lu_byte marked