common/luaobject.c

   1 /*
   2  * luaobject.c - useful functions for handling Lua objects
   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 #include "common/luaobject.h"
  23
  24 /** Setup the object system at startup.
  25  * \param L The Lua VM state.
  26  */
  27 void
  28 luaA_object_setup(lua_State *L)
  29 {
  30     /* Push identification string */
  31     lua_pushliteral(L, LUAA_OBJECT_REGISTRY_KEY);
  32     /* Create an empty table */
  33     lua_newtable(L);
  34     /* Create an empty metatable */
  35     lua_newtable(L);
  36     /* Set this empty table as the registry metatable.
  37      * It's used to store the number of reference on stored objects. */
  38     lua_setmetatable(L, -2);
  39     /* Register table inside registry */
  40     lua_rawset(L, LUA_REGISTRYINDEX);
  41 }
  42
  43 /** Increment a object reference in its store table.
  44  * \param L The Lua VM state.
  45  * \param tud The table index on the stack.
  46  * \param oud The object index on the stack.
  47  * \return A pointer to the object.
  48  */
  49 void *
  50 luaA_object_incref(lua_State *L, int tud, int oud)
  51 {
  52     /* Get pointer value of the item */
  53     void *pointer = (void *) lua_topointer(L, oud);
  54
  55     /* Not reference able. */
  56     if(!pointer)
  57     {
  58         lua_remove(L, oud);
  59         return NULL;
  60     }
  61
  62     /* Push the pointer (key) */
  63     lua_pushlightuserdata(L, pointer);
  64     /* Push the data (value) */
  65     lua_pushvalue(L, oud < 0 ? oud - 1 : oud);
  66     /* table.lightudata = data */
  67     lua_rawset(L, tud < 0 ? tud - 2 : tud);
  68
  69     /* refcount++ */
  70
  71     /* Get the metatable */
  72     lua_getmetatable(L, tud);
  73     /* Push the pointer (key) */
  74     lua_pushlightuserdata(L, pointer);
  75     /* Get the number of references */
  76     lua_rawget(L, -2);
  77     /* Get the number of references and increment it */
  78     int count = lua_tonumber(L, -1) + 1;
  79     lua_pop(L, 1);
  80     /* Push the pointer (key) */
  81     lua_pushlightuserdata(L, pointer);
  82     /* Push count (value) */
  83     lua_pushinteger(L, count);
  84     /* Set metatable[pointer] = count */
  85     lua_rawset(L, -3);
  86     /* Pop metatable */
  87     lua_pop(L, 1);
  88
  89     /* Remove referenced item */
  90     lua_remove(L, oud);
  91
  92     return pointer;
  93 }
  94
  95 /** Decrement a object reference in its store table.
  96  * \param L The Lua VM state.
  97  * \param tud The table index on the stack.
  98  * \param oud The object index on the stack.
  99  * \return A pointer to the object.
 100  */
 101 void
 102 luaA_object_decref(lua_State *L, int tud, void *pointer)
 103 {
 104     if(!pointer)
 105         return;
 106
 107     /* First, refcount-- */
 108     /* Get the metatable */
 109     lua_getmetatable(L, tud);
 110     /* Push the pointer (key) */
 111     lua_pushlightuserdata(L, pointer);
 112     /* Get the number of references */
 113     lua_rawget(L, -2);
 114     /* Get the number of references and decrement it */
 115     int count = lua_tonumber(L, -1) - 1;
 116     lua_pop(L, 1);
 117     /* Push the pointer (key) */
 118     lua_pushlightuserdata(L, pointer);
 119     /* Hasn't the ref reached 0? */
 120     if(count)
 121         lua_pushinteger(L, count);
 122     else
 123         /* Yup, delete it, set nil as value */
 124         lua_pushnil(L);
 125     /* Set meta[pointer] = count/nil */
 126     lua_rawset(L, -3);
 127     /* Pop metatable */
 128     lua_pop(L, 1);
 129
 130     /* Wait, no more ref? */
 131     if(!count)
 132     {
 133         /* Yes? So remove it from table */
 134         lua_pushlightuserdata(L, pointer);
 135         /* Push nil as value */
 136         lua_pushnil(L);
 137         /* table[pointer] = nil */
 138         lua_rawset(L, tud < 0 ? tud - 2 : tud);
 139     }
 140 }
 141
 142 int
 143 luaA_settype(lua_State *L, lua_class_t *lua_class)
 144 {
 145     lua_pushlightuserdata(L, lua_class);
 146     lua_rawget(L, LUA_REGISTRYINDEX);
 147     lua_setmetatable(L, -2);
 148     return 1;
 149 }
 150
 151 void
 152 luaA_object_connect_signal(lua_State *L, int oud,
 153                            const char *name, lua_CFunction fn)
 154 {
 155     lua_pushcfunction(L, fn);
 156     luaA_object_connect_signal_from_stack(L, oud, name, -1);
 157 }
 158
 159 void
 160 luaA_object_disconnect_signal(lua_State *L, int oud,
 161                               const char *name, lua_CFunction fn)
 162 {
 163     lua_pushcfunction(L, fn);
 164     luaA_object_disconnect_signal_from_stack(L, oud, name, -1);
 165 }
 166
 167 /** Add a signal to an object.
 168  * \param L The Lua VM state.
 169  * \param oud The object index on the stack.
 170  * \param name The name of the signal.
 171  * \param ud The index of function to call when signal is emitted.
 172  */
 173 void
 174 luaA_object_connect_signal_from_stack(lua_State *L, int oud,
 175                                       const char *name, int ud)
 176 {
 177     luaA_checkfunction(L, ud);
 178     lua_object_t *obj = lua_touserdata(L, oud);
 179     signal_connect(&obj->signals, name, luaA_object_ref_item(L, oud, ud));
 180 }
 181
 182 /** Remove a signal to an object.
 183  * \param L The Lua VM state.
 184  * \param oud The object index on the stack.
 185  * \param name The name of the signal.
 186  * \param ud The index of function to call when signal is emitted.
 187  */
 188 void
 189 luaA_object_disconnect_signal_from_stack(lua_State *L, int oud,
 190                                          const char *name, int ud)
 191 {
 192     luaA_checkfunction(L, ud);
 193     lua_object_t *obj = lua_touserdata(L, oud);
 194     void *ref = (void *) lua_topointer(L, ud);
 195     signal_disconnect(&obj->signals, name, ref);
 196     luaA_object_unref_item(L, oud, ref);
 197     lua_remove(L, ud);
 198 }
 199
 200 void
 201 signal_object_emit(lua_State *L, signal_array_t *arr, const char *name, int nargs)
 202 {
 203     signal_t *sigfound = signal_array_getbyid(arr,
 204                                               a_strhash((const unsigned char *) name));
 205
 206     if(sigfound)
 207     {
 208         int nbfunc = sigfound->sigfuncs.len;
 209         luaL_checkstack(L, lua_gettop(L) + nbfunc + nargs + 1, "too much signal");
 210         /* Push all functions and then execute, because this list can change
 211          * while executing funcs. */
 212         foreach(func, sigfound->sigfuncs)
 213             luaA_object_push(L, (void *) *func);
 214
 215         for(int i = 0; i < nbfunc; i++)
 216         {
 217             /* push all args */
 218             for(int j = 0; j < nargs; j++)
 219                 lua_pushvalue(L, - nargs - nbfunc + i);
 220             /* push first function */
 221             lua_pushvalue(L, - nargs - nbfunc + i);
 222             /* remove this first function */
 223             lua_remove(L, - nargs - nbfunc - 1 + i);
 224             luaA_dofunction(L, nargs, 0);
 225         }
 226     } else
 227         warn("Trying to emit unknown signal '%s'", name);
 228
 229     /* remove args */
 230     lua_pop(L, nargs);
 231 }
 232
 233 /** Emit a signal to an object.
 234  * \param L The Lua VM state.
 235  * \param oud The object index on the stack.
 236  * \param name The name of the signal.
 237  * \param nargs The number of arguments to pass to the called functions.
 238  */
 239 void
 240 luaA_object_emit_signal(lua_State *L, int oud,
 241                         const char *name, int nargs)
 242 {
 243     int oud_abs = luaA_absindex(L, oud);
 244     lua_object_t *obj = lua_touserdata(L, oud);
 245     if(!obj)
 246         luaL_error(L, "trying to emit signal on non-object");
 247     signal_t *sigfound = signal_array_getbyid(&obj->signals,
 248                                               a_strhash((const unsigned char *) name));
 249     if(sigfound)
 250     {
 251         int nbfunc = sigfound->sigfuncs.len;
 252         luaL_checkstack(L, lua_gettop(L) + nbfunc + nargs + 2, "too much signal");
 253         /* Push all functions and then execute, because this list can change
 254          * while executing funcs. */
 255         foreach(func, sigfound->sigfuncs)
 256             luaA_object_push_item(L, oud_abs, (void *) *func);
 257
 258         for(int i = 0; i < nbfunc; i++)
 259         {
 260             /* push object */
 261             lua_pushvalue(L, oud_abs);
 262             /* push all args */
 263             for(int j = 0; j < nargs; j++)
 264                 lua_pushvalue(L, - nargs - nbfunc - 1 + i);
 265             /* push first function */
 266             lua_pushvalue(L, - nargs - nbfunc - 1 + i);
 267             /* remove this first function */
 268             lua_remove(L, - nargs - nbfunc - 2 + i);
 269             luaA_dofunction(L, nargs + 1, 0);
 270         }
 271     } else
 272         warn("Trying to emit unknown signal '%s'", name);
 273
 274     /* Then emit signal on the class */
 275     lua_pushvalue(L, oud);
 276     lua_insert(L, - nargs - 1);
 277     luaA_class_emit_signal(L, luaA_class_get(L, - nargs - 1), name, nargs + 1);
 278 }
 279
 280 int
 281 luaA_object_connect_signal_simple(lua_State *L)
 282 {
 283     luaA_object_connect_signal_from_stack(L, 1, luaL_checkstring(L, 2), 3);
 284     return 0;
 285 }
 286
 287 int
 288 luaA_object_disconnect_signal_simple(lua_State *L)
 289 {
 290     luaA_object_disconnect_signal_from_stack(L, 1, luaL_checkstring(L, 2), 3);
 291     return 0;
 292 }
 293
 294 int
 295 luaA_object_emit_signal_simple(lua_State *L)
 296 {
 297     luaA_object_emit_signal(L, 1, luaL_checkstring(L, 2), lua_gettop(L) - 2);
 298     return 0;
 299 }
 300
 301 int
 302 luaA_object_tostring(lua_State *L)
 303 {
 304     lua_class_t *lua_class = luaA_class_get(L, 1);
 305     lua_object_t *object = luaA_checkudata(L, 1, lua_class);
 306
 307     int i = 0;
 308     for(; lua_class; lua_class = lua_class->parent, i++)
 309     {
 310         if(i)
 311         {
 312             lua_pushliteral(L, "/");
 313             lua_insert(L, - (i * 2));
 314         }
 315         lua_pushstring(L, NONULL(lua_class->name));
 316         lua_insert(L, - (i * 2) - 1);
 317     }
 318
 319     lua_pushfstring(L, ": %p", object);
 320
 321     lua_concat(L, i * 2);
 322
 323     return 1;
 324 }
 325
 326 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80