common/lualib.h

   1 /*
   2  * lualib.h - useful functions and type for Lua
   3  *
   4  * Copyright © 2009 Julien Danjou <julien@danjou.info>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  */
  21
  22 #ifndef AWESOME_COMMON_LUALIB
  23 #define AWESOME_COMMON_LUALIB
  24
  25 #include <lauxlib.h>
  26 #include "common/util.h"
  27
  28 #define luaA_checkfunction(L, n) \
  29     do { \
  30         if(!lua_isfunction(L, n)) \
  31             luaL_typerror(L, n, "function"); \
  32     } while(0)
  33
  34 /** Dump the Lua stack. Useful for debugging.
  35  * \param L The Lua VM state.
  36  */
  37 static inline void
  38 luaA_dumpstack(lua_State *L)
  39 {
  40     fprintf(stderr, "-------- Lua stack dump ---------\n");
  41     for(int i = lua_gettop(L); i; i--)
  42     {
  43         int t = lua_type(L, i);
  44         switch (t)
  45         {
  46           case LUA_TSTRING:
  47             fprintf(stderr, "%d: string: `%s'\n", i, lua_tostring(L, i));
  48             break;
  49           case LUA_TBOOLEAN:
  50             fprintf(stderr, "%d: bool:   %s\n", i, lua_toboolean(L, i) ? "true" : "false");
  51             break;
  52           case LUA_TNUMBER:
  53             fprintf(stderr, "%d: number: %g\n", i, lua_tonumber(L, i));
  54             break;
  55           case LUA_TNIL:
  56             fprintf(stderr, "%d: nil\n", i);
  57             break;
  58           default:
  59             fprintf(stderr, "%d: %s\t#%d\t%p\n", i, lua_typename(L, t),
  60                     (int) lua_objlen(L, i),
  61                     lua_topointer(L, i));
  62             break;
  63         }
  64     }
  65     fprintf(stderr, "------- Lua stack dump end ------\n");
  66 }
  67
  68 /** Convert s stack index to positive.
  69  * \param L The Lua VM state.
  70  * \param ud The index.
  71  * \return A positive index.
  72  */
  73 static inline int
  74 luaA_absindex(lua_State *L, int ud)
  75 {
  76     return (ud > 0 || ud <= LUA_REGISTRYINDEX) ? ud : lua_gettop(L) + ud + 1;
  77 }
  78
  79 /** Execute an Lua function on top of the stack.
  80  * \param L The Lua stack.
  81  * \param nargs The number of arguments for the Lua function.
  82  * \param nret The number of returned value from the Lua function.
  83  * \return True on no error, false otherwise.
  84  */
  85 static inline bool
  86 luaA_dofunction(lua_State *L, int nargs, int nret)
  87 {
  88     if(nargs)
  89         lua_insert(L, - (nargs + 1));
  90     if(lua_pcall(L, nargs, nret, 0))
  91     {
  92         warn("error running function: %s",
  93              lua_tostring(L, -1));
  94         lua_pop(L, 1);
  95         return false;
  96     }
  97     return true;
  98 }
  99
 100 /** Convert a object to a udata if possible.
 101  * \param L The Lua VM state.
 102  * \param ud The index.
 103  * \param tname The type name.
 104  * \return A pointer to the object, NULL otherwise.
 105  */
 106 static inline void *
 107 luaA_toudata(lua_State *L, int ud, const char *tname)
 108 {
 109     void *p = lua_touserdata(L, ud);
 110     if(p) /* value is a userdata? */
 111         if(lua_getmetatable(L, ud)) /* does it have a metatable? */
 112         {
 113             lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
 114             if(!lua_rawequal(L, -1, -2)) /* does it have the correct mt? */
 115                 p = NULL;
 116             lua_pop(L, 2); /* remove both metatables */
 117         }
 118     return p;
 119 }
 120
 121 #endif
 122
 123 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80