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 #include "common/backtrace.h"
  24
  25 /** Setup the object system at startup.
  26  * \param L The Lua VM state.
  27  */
  28 void
  29 luaA_object_setup(lua_State *L)
  30 {
  31     /* Push identification string */
  32     lua_pushliteral(L, LUAA_OBJECT_REGISTRY_KEY);
  33     /* Create an empty table */
  34     lua_newtable(L);
  35     /* Create an empty metatable */
  36     lua_newtable(L);
  37     /* Set this empty table as the registry metatable.
  38      * It's used to store the number of reference on stored objects. */
  39     lua_setmetatable(L, -2);
  40     /* Register table inside registry */
  41     lua_rawset(L, LUA_REGISTRYINDEX);
  42 }
  43
  44 /** Increment a object reference in its store table.
  45  * \param L The Lua VM state.
  46  * \param tud The table index on the stack.
  47  * \param oud The object index on the stack.
  48  * \return A pointer to the object.
  49  */
  50 void *
  51 luaA_object_incref(lua_State *L, int tud, int oud)
  52 {
  53     /* Get pointer value of the item */
  54     void *pointer = (void *) lua_topointer(L, oud);
  55
  56     /* Not reference able. */
  57     if(!pointer)
  58     {
  59         lua_remove(L, oud);
  60         return NULL;
  61     }
  62
  63     /* Push the pointer (key) */
  64     lua_pushlightuserdata(L, pointer);
  65     /* Push the data (value) */
  66     lua_pushvalue(L, oud < 0 ? oud - 1 : oud);
  67     /* table.lightudata = data */
  68     lua_rawset(L, tud < 0 ? tud - 2 : tud);
  69
  70     /* refcount++ */
  71
  72     /* Get the metatable */
  73     lua_getmetatable(L, tud);
  74     /* Push the pointer (key) */
  75     lua_pushlightuserdata(L, pointer);
  76     /* Get the number of references */
  77     lua_rawget(L, -2);
  78     /* Get the number of references and increment it */
  79     int count = lua_tonumber(L, -1) + 1;
  80     lua_pop(L, 1);
  81     /* Push the pointer (key) */
  82     lua_pushlightuserdata(L, pointer);
  83     /* Push count (value) */
  84     lua_pushinteger(L, count);
  85     /* Set metatable[pointer] = count */
  86     lua_rawset(L, -3);
  87     /* Pop metatable */
  88     lua_pop(L, 1);
  89
  90     /* Remove referenced item */
  91     lua_remove(L, oud);
  92
  93     return pointer;
  94 }
  95
  96 /** Decrement a object reference in its store table.
  97  * \param L The Lua VM state.
  98  * \param tud The table index on the stack.
  99  * \param oud The object index on the stack.
 100  * \return A pointer to the object.
 101  */
 102 void
 103 luaA_object_decref(lua_State *L, int tud, const void *pointer)
 104 {
 105     if(!pointer)
 106         return;
 107
 108     /* First, refcount-- */
 109     /* Get the metatable */
 110     lua_getmetatable(L, tud);
 111     /* Push the pointer (key) */
 112     lua_pushlightuserdata(L, (void *) pointer);
 113     /* Get the number of references */
 114     lua_rawget(L, -2);
 115     /* Get the number of references and decrement it */
 116     int count = lua_tonumber(L, -1) - 1;
 117     /* Did we find the item in our table? (tonumber(nil)-1) is -1 */
 118     if (count < 0)
 119     {
 120         buffer_t buf;
 121         backtrace_get(&buf);
 122         warn("BUG: Reference not found: %d %p\n%s", tud, pointer, buf.s);
 123
 124         /* Pop reference count and metatable */
 125         lua_pop(L, 2);
 126         return;
 127     }
 128     lua_pop(L, 1);
 129     /* Push the pointer (key) */
 130     lua_pushlightuserdata(L, (void *) pointer);
 131     /* Hasn't the ref reached 0? */
 132     if(count)
 133         lua_pushinteger(L, count);
 134     else
 135         /* Yup, delete it, set nil as value */
 136         lua_pushnil(L);
 137     /* Set meta[pointer] = count/nil */
 138     lua_rawset(L, -3);
 139     /* Pop metatable */
 140     lua_pop(L, 1);
 141
 142     /* Wait, no more ref? */
 143     if(!count)
 144     {
 145         /* Yes? So remove it from table */
 146         lua_pushlightuserdata(L, (void *) pointer);
 147         /* Push nil as value */
 148         lua_pushnil(L);
 149         /* table[pointer] = nil */
 150         lua_rawset(L, tud < 0 ? tud - 2 : tud);
 151     }
 152 }
 153
 154 int
 155 luaA_settype(lua_State *L, lua_class_t *lua_class)
 156 {
 157     lua_pushlightuserdata(L, lua_class);
 158     lua_rawget(L, LUA_REGISTRYINDEX);
 159     lua_setmetatable(L, -2);
 160     return 1;
 161 }
 162
 163 void
 164 luaA_object_connect_signal(lua_State *L, int oud,
 165                            const char *name, lua_CFunction fn)
 166 {
 167     lua_pushcfunction(L, fn);
 168     luaA_object_connect_signal_from_stack(L, oud, name, -1);
 169 }
 170
 171 void
 172 luaA_object_disconnect_signal(lua_State *L, int oud,
 173                               const char *name, lua_CFunction fn)
 174 {
 175     lua_pushcfunction(L, fn);
 176     luaA_object_disconnect_signal_from_stack(L, oud, name, -1);
 177 }
 178
 179 /** Add a signal to an object.
 180  * \param L The Lua VM state.
 181  * \param oud The object index on the stack.
 182  * \param name The name of the signal.
 183  * \param ud The index of function to call when signal is emitted.
 184  */
 185 void
 186 luaA_object_connect_signal_from_stack(lua_State *L, int oud,
 187                                       const char *name, int ud)
 188 {
 189     luaA_checkfunction(L, ud);
 190     lua_object_t *obj = lua_touserdata(L, oud);
 191     signal_connect(&obj->signals, name, luaA_object_ref_item(L, oud, ud));
 192 }
 193
 194 /** Remove a signal to an object.
 195  * \param L The Lua VM state.
 196  * \param oud The object index on the stack.
 197  * \param name The name of the signal.
 198  * \param ud The index of function to call when signal is emitted.
 199  */
 200 void
 201 luaA_object_disconnect_signal_from_stack(lua_State *L, int oud,
 202                                          const char *name, int ud)
 203 {
 204     luaA_checkfunction(L, ud);
 205     lua_object_t *obj = lua_touserdata(L, oud);
 206     void *ref = (void *) lua_topointer(L, ud);
 207     signal_disconnect(&obj->signals, name, ref);
 208     luaA_object_unref_item(L, oud, ref);
 209     lua_remove(L, ud);
 210 }
 211
 212 void
 213 signal_object_emit(lua_State *L, signal_array_t *arr, const char *name, int nargs)
 214 {
 215     signal_t *sigfound = signal_array_getbyid(arr,
 216                                               a_strhash((const unsigned char *) name));
 217
 218     if(sigfound)
 219     {
 220         int nbfunc = sigfound->sigfuncs.len;
 221         luaL_checkstack(L, lua_gettop(L) + nbfunc + nargs + 1, "too much signal");
 222         /* Push all functions and then execute, because this list can change
 223          * while executing funcs. */
 224         foreach(func, sigfound->sigfuncs)
 225             luaA_object_push(L, *func);
 226
 227         for(int i = 0; i < nbfunc; i++)
 228         {
 229             /* push all args */
 230             for(int j = 0; j < nargs; j++)
 231                 lua_pushvalue(L, - nargs - nbfunc + i);
 232             /* push first function */
 233             lua_pushvalue(L, - nargs - nbfunc + i);
 234             /* remove this first function */
 235             lua_remove(L, - nargs - nbfunc - 1 + i);
 236             luaA_dofunction(L, nargs, 0);
 237         }
 238     } else
 239         warn("Trying to emit unknown signal '%s'", name);
 240
 241     /* remove args */
 242     lua_pop(L, nargs);
 243 }
 244
 245 /** Emit a signal to an object.
 246  * \param L The Lua VM state.
 247  * \param oud The object index on the stack.
 248  * \param name The name of the signal.
 249  * \param nargs The number of arguments to pass to the called functions.
 250  */
 251 void
 252 luaA_object_emit_signal(lua_State *L, int oud,
 253                         const char *name, int nargs)
 254 {
 255     int oud_abs = luaA_absindex(L, oud);
 256     lua_object_t *obj = lua_touserdata(L, oud);
 257     if(!obj) {
 258         warn("Trying to emit signal '%s' on non-object", name);
 259         return;
 260     }
 261     signal_t *sigfound = signal_array_getbyid(&obj->signals,
 262                                               a_strhash((const unsigned char *) name));
 263     if(sigfound)
 264     {
 265         int nbfunc = sigfound->sigfuncs.len;
 266         luaL_checkstack(L, lua_gettop(L) + nbfunc + nargs + 2, "too much signal");
 267         /* Push all functions and then execute, because this list can change
 268          * while executing funcs. */
 269         foreach(func, sigfound->sigfuncs)
 270             luaA_object_push_item(L, oud_abs, *func);
 271
 272         for(int i = 0; i < nbfunc; i++)
 273         {
 274             /* push object */
 275             lua_pushvalue(L, oud_abs);
 276             /* push all args */
 277             for(int j = 0; j < nargs; j++)
 278                 lua_pushvalue(L, - nargs - nbfunc - 1 + i);
 279             /* push first function */
 280             lua_pushvalue(L, - nargs - nbfunc - 1 + i);
 281             /* remove this first function */
 282             lua_remove(L, - nargs - nbfunc - 2 + i);
 283             luaA_dofunction(L, nargs + 1, 0);
 284         }
 285     } else
 286         warn("Trying to emit unknown signal '%s'", name);
 287
 288     /* Then emit signal on the class */
 289     lua_pushvalue(L, oud);
 290     lua_insert(L, - nargs - 1);
 291     luaA_class_emit_signal(L, luaA_class_get(L, - nargs - 1), name, nargs + 1);
 292 }
 293
 294 int
 295 luaA_object_connect_signal_simple(lua_State *L)
 296 {
 297     luaA_object_connect_signal_from_stack(L, 1, luaL_checkstring(L, 2), 3);
 298     return 0;
 299 }
 300
 301 int
 302 luaA_object_disconnect_signal_simple(lua_State *L)
 303 {
 304     luaA_object_disconnect_signal_from_stack(L, 1, luaL_checkstring(L, 2), 3);
 305     return 0;
 306 }
 307
 308 int
 309 luaA_object_emit_signal_simple(lua_State *L)
 310 {
 311     luaA_object_emit_signal(L, 1, luaL_checkstring(L, 2), lua_gettop(L) - 2);
 312     return 0;
 313 }
 314
 315 int
 316 luaA_object_tostring(lua_State *L)
 317 {
 318     lua_class_t *lua_class = luaA_class_get(L, 1);
 319     lua_object_t *object = luaA_checkudata(L, 1, lua_class);
 320
 321     int i = 0;
 322     for(; lua_class; lua_class = lua_class->parent, i++)
 323     {
 324         if(i)
 325         {
 326             lua_pushliteral(L, "/");
 327             lua_insert(L, - (i * 2));
 328         }
 329         lua_pushstring(L, NONULL(lua_class->name));
 330         lua_insert(L, - (i * 2) - 1);
 331     }
 332
 333     lua_pushfstring(L, ": %p", object);
 334
 335     lua_concat(L, i * 2);
 336
 337     return 1;
 338 }
 339
 340 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80