lua学习笔记（2）——内核入口

lua.c:595 main()

luaL_newstate();                    //create new stack L
lua_pushcfunction(L, &pmain);       //push pmin into L
lua_pushinteger(L, argc);           //push argc into L
lua_pushlightuserdata(L, argv);     //push argv into L
status = lua_pcall(L, 2, 1, 0);     //call top function from L
result = lua_toboolean(L, -1);      //get function result form L
report(L, status);                  //print error from L when result not ok
lua_close(L);                       //clear all in L

lua.c:553 pmain()

int argc = (int)lua_tointeger(L, 1);            //get argc from L
char **argv = (char **)lua_touserdata(L, 2);    //get argv from L
int args = collectargs(argv, &script);          //decode argv to args(mask with [error,-i,-v,-e,-E]) 
args == has_error                               //when argv has error
args & has_v                                    //-v to show lua version
args & has_E                                    //-E to ignore env vars(use std lib)                 
runargs(L, argv, script)                        //check -e and -l
handle_script(L, argv + script)                 //run script from L
args & has_i                                    //-i to do read-eval-print loop
lua_stdin_is_tty()                              //run from shell
dofile(L, NULL)                                 //run from file
lua_pushboolean(L, 1)                           //write ok/error to L

lua.c:436 handle_script()

const char *fname = argv[0];            //script file name
status = luaL_loadfile(L, fname);       //read file and push into L
int n = pushargs(L);                    //push arguments to script in L
status = docall(L, n, LUA_MULTRET);     //run code from L

lua.c:404 doREPL()

const char *oldprogname = progname;         //backup progname
progname = NULL;                            //no progname in interactive mode
while ((status = loadline(L)) != -1) {      //read input while not EOF
    if (status == LUA_OK)
        status = docall(L, 0, LUA_MULTRET); //run code from L
    if (status == LUA_OK) l_print(L);       //print result 
    else report(L, status);                 //print error info 
}       
lua_settop(L, 0);                           //clear L
lua_writeline();                            //print '\n'
progname = oldprogname;                     //recover progname

lua.c:245 dofile()

luaL_loadfile(L,name)->luaL_loadfilexj(L,name,NULL)     //read from file and push into L.(simple and skip)
dochunk(L, luaL_loadfile(L, name)->docall(L,0,0)    //run code from L

lua.c:198 docall()

docall(L,narg,nres)->lua_pcall(L,narg,nres,base)->lua_pcallk(L,narg,nres,base,0,NULL)

lapi.c:919 lua_pcallk()

struct CallS c;
int status;
ptrdiff_t func;
lua_lock(L);                                //multi-thread api to acquire lock for L
api_check(k == NULL || !isLua(L->ci),       //defined as assert(e && msg), when e = false, interrupt
        "cannot use continuations inside hooks");
api_checknelems(L, nargs+1);
api_check(L->status == LUA_OK, "cannot do calls on non-normal thread");
checkresults(L, nargs, nresults);
if (errfunc == 0)
    func = 0;
    else {
        StkId o = index2addr(L, errfunc);   //convert index to address in L
        api_checkstackindex(errfunc, o);    //check stkid
        func = savestack(L, o);             //error function

    }
c.func = L->top - (nargs+1);                //the function need to call in stack
if (k == NULL || L->nny > 0) {              //status is not protected
    c.nresults = nresults;
    status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);     //call c.func in protected
}
else {                                      //status is protected by 'resume'
    CallInfo *ci = L->ci;
    ci->u.c.k = k;                          //save details to ci,start.
    ci->u.c.ctx = ctx;
    ci->extra = savestack(L, c.func);
    ci->u.c.old_errfunc = L->errfunc;       //backup error function
    L->errfunc = func;
    setoah(ci->callstatus, L->allowhook);
    ci->callstatus |= CIST_YPCALL;          //save details to ci,end.
    luaD_call(L, c.func, nresults, 1);      //call c.call
    ci->callstatus &= ~CIST_YPCALL;
    L->errfunc = ci->u.c.old_errfunc;       //recovery error function
    status = LUA_OK;
}
adjustresults(L, nresults);
lua_unlock(L);                              //multi-thread api to release lock for L
return status;

---

call structure

Created with Raphaël 2.1.2 main main pmain pmain docall docall lua_pcallk lua_pcallk luaD_call luaD_call luaD_pcall luaD_pcall handle_script doREPL dofile lua_pcall

main->pmain
pmain->handle_script->luaL_loadfile->luaL_loadfilex->docall
pmain->doREPL->loop(docall)
pmain->dofile->luaL_loadfilexj->docall
docall->lua_pcall->lua_pcallk
lua_pcallk->luaD_pcall
lua_pcallk->luaD_call