lua/luadebug.c

   1 #include <lua.h>
   2 #include <lauxlib.h>
   3 #include <lualib.h>
   4
   5 #define LEVELS1 12      /* size of the first part of the stack */
   6 #define LEVELS2 10      /* size of the second part of the stack */
   7
   8 /* stolen from ldblib.c as I can't figure out how to import it! */
   9
  10 static lua_State *getthread (lua_State *L, int *arg) {
  11   if (lua_isthread(L, 1)) {
  12     *arg = 1;
  13     return lua_tothread(L, 1);
  14   }
  15   else {
  16     *arg = 0;
  17     return L;
  18   }
  19 }
  20
  21 static int db_errorfb (lua_State *L) {
  22   int level;
  23   int firstpart = 1;  /* still before eventual `...' */
  24   int arg;
  25   lua_State *L1 = getthread(L, &arg);
  26   lua_Debug ar;
  27   if (lua_isnumber(L, arg+2)) {
  28     level = (int)lua_tointeger(L, arg+2);
  29     lua_pop(L, 1);
  30   }
  31   else
  32     level = (L == L1) ? 1 : 0;  /* level 0 may be this own function */
  33   if (lua_gettop(L) == arg)
  34     lua_pushliteral(L, "");
  35   else if (!lua_isstring(L, arg+1)) return 1;  /* message is not a string */
  36   else lua_pushliteral(L, "\n");
  37
  38   lua_pushliteral(L, "stack traceback:");
  39   while (lua_getstack(L1, level++, &ar)) {
  40     if (level > LEVELS1 && firstpart) {
  41       /* no more than `LEVELS2' more levels? */
  42       if (!lua_getstack(L1, level+LEVELS2, &ar))
  43         level--;  /* keep going */
  44       else {
  45         lua_pushliteral(L, "\n\t...");  /* too many levels */
  46         while (lua_getstack(L1, level+LEVELS2, &ar))  /* find last levels */
  47           level++;
  48       }
  49       firstpart = 0;
  50       continue;
  51     }
  52     lua_pushliteral(L, "\n\t");
  53     lua_getinfo(L1, "Snl", &ar);
  54     lua_pushfstring(L, "%s:", ar.short_src);
  55     if (ar.currentline > 0)
  56       lua_pushfstring(L, "%d:", ar.currentline);
  57     if (*ar.namewhat != '\0')  /* is there a name? */
  58         lua_pushfstring(L, " in function " LUA_QS, ar.name);
  59     else {
  60       if (*ar.what == 'm')  /* main? */
  61         lua_pushfstring(L, " in main chunk");
  62       else if (*ar.what == 'C' || *ar.what == 't')
  63         lua_pushliteral(L, " ?");  /* C function or tail call */
  64       else
  65         lua_pushfstring(L, " in function <%s:%d>",
  66                            ar.short_src, ar.linedefined);
  67     }
  68     lua_concat(L, lua_gettop(L) - arg);
  69   }
  70   lua_concat(L, lua_gettop(L) - arg);
  71   return 1;
  72 }
  73
  74 void lua_registerdebug(lua_State *l) {
  75   lua_register(l, "traceback", db_errorfb);
  76 }
  77