src/gr_util.c

   1 /*=========================================================================*\
   2  * LuaGRAPH toolkit
   3  * Graph support for Lua.
   4  * Herbert Leuwer
   5  * 30-7-2006, 01/2017
   6  *
   7  * Utilities
   8  *
   9 \*=========================================================================*/
  10
  11 /*=========================================================================*\
  12  * Includes
  13 \*=========================================================================*/
  14 #include <string.h>
  15 #include <stdlib.h>
  16 #include "lua.h"
  17 #include "lauxlib.h"
  18 #include "gr_graph.h"
  19
  20 /*=========================================================================* \
  21  * Functions
  22 \*=========================================================================*/
  23 static unsigned int localid = 0;
  24
  25 unsigned int newid(void){
  26   localid = localid + 1;
  27   return localid;
  28 }
  29
  30 /*
  31  * Convert numerical kind indication into readable text string.
  32  */
  33 char *agobjkindstr(struct Agobj_s *obj)
  34 {
  35   int kind = agobjkind(obj);
  36   return kind == AGRAPH ? "graph" : kind == AGNODE ? "node" : kind == AGEDGE ? "edge" : "unknown";
  37 }
  38
  39 /*
  40  * Insertion callback: called when an object is inserted by cgraph.
  41  * Used to register proxy object on top of stack in Lua registry using cgraph object as key.
  42  */
  43 void cb_insert(struct Agraph_s *g, struct Agobj_s *obj, void *L)
  44 {
  45   /* register user data on top of stack */
  46   TRACE("   cb_insert(): register object '%s' type: %s\n", agnameof(obj), agobjkindstr(obj));
  47   set_object((lua_State *)L, (void *) obj);
  48 }
  49
  50 /*
  51  * Deletion callback: called when an object is inserted by cgraph.
  52  * De-register proxy object.
  53  */
  54 void cb_delete(Agraph_t *g, Agobj_t *obj, void *L)
  55 {
  56   char *skey;
  57
  58   TRACE("   cb_delete() : unregister object '%s' kind=%s ptr=%p\n", agnameof(obj),
  59         agobjkind(obj) == AGRAPH ? "graph" : agobjkind(obj) == AGNODE ? "node" :
  60         agobjkind(obj) == AGEDGE ? "edge" : "unknown", obj);
  61   skey = agget(obj, "__attrib__");
  62   if (skey && (strlen(skey) != 0)) {
  63     printf("   cb_delete(): nulling attrib\n");
  64     lua_pushstring(L, skey);
  65     lua_pushnil(L);
  66     lua_rawset(L, LUA_REGISTRYINDEX);
  67     agset(obj, "__attrib__", NULL);
  68     agstrfree(agroot(obj), skey);
  69   }
  70   del_object(L, obj);
  71 }
  72
  73 /*
  74  * Modification callback. Not used by LuaGRAPH
  75  */
  76 void cb_modify(Agraph_t *g, Agobj_t *obj, void *L, Agsym_t *sym)
  77 {
  78   TRACE("   cb_modify(): modify object '%s'\n", agnameof(obj));
  79 }
  80
  81 /*
  82  * Query Lua stack for an object
  83  */
  84 gr_object_t *toobject(lua_State *L, int narg, const char *type, int strict)
  85 {
  86   gr_object_t *ud;
  87
  88   if (type != NULL){
  89     ud = luaL_checkudata(L, narg, type);
  90   } else {
  91     ud = lua_touserdata(L, narg);
  92   }
  93   if (!ud){
  94     luaL_error(L, "bad argument %d (valid userdata `%s' expected; null received)",
  95                narg, (type) ? type : "???");
  96     return NULL;
  97   }
  98     if (strict && (ud->p.p == NULL)){
  99       luaL_error(L, "bad argument #%d (valid userdata `%s' %d expected: invalid received)",
 100                narg, (type) ? type : "???", ud->p.status);
 101     lua_error(L);
 102     return NULL;
 103   }
 104   return ud;
 105 }
 106
 107 /*
 108  * Register an object in Lua registry.
 109  */
 110 int set_object(lua_State *L, void *key)
 111 {
 112   TRACE("   set_object(): key=%p (%s %d)\n", key, __FILE__, __LINE__);
 113   lua_pushlightuserdata(L, key);       /* ud, key */
 114   lua_pushvalue(L, -2);                /* ud, key, ud */
 115   lua_rawset(L, LUA_REGISTRYINDEX);    /* ud */
 116   return 1;
 117 }
 118
 119 int set_status(lua_State *L, void *key, int status)
 120 {
 121   gr_object_t *ud;
 122
 123   lua_pushlightuserdata(L, key);       /* ?, key */
 124   lua_rawget(L, LUA_REGISTRYINDEX);
 125   ud = lua_touserdata(L, -1);
 126   if (ud)
 127     ud->p.status = status;
 128   return 0;
 129 }
 130 /*
 131  * Delete an object from Lua registry.
 132  */
 133 int del_object(lua_State *L, void *key)
 134 {
 135   TRACE("   del_object(): key=%p '%s' (%s %d)\n", key, agnameof(key), __FILE__, __LINE__);
 136   set_status(L, key, DEAD);
 137   lua_pushlightuserdata(L, key);
 138   lua_pushnil(L);                      /* ?, key, nil */
 139   lua_rawset(L, LUA_REGISTRYINDEX);    /* ? */
 140   return 0;
 141 }
 142
 143 /*-------------------------------------------------------------------------*\
 144  * Property: status [string]
 145  * Returns the string "alive" or "dead" for the given graph.
 146  * Use to test whether a reference to a graph object kept in a lua variable
 147  * is still alive.
 148  * Example:
 149  * b = g.status
 150 \*-------------------------------------------------------------------------*/
 151 int gr_status(lua_State *L)
 152 {
 153   gr_object_t *ud = toobject(L, 1, NULL, NONSTRICT);
 154   if (ud){
 155     if (ud->p.status == ALIVE)
 156       lua_pushstring(L, "alive");
 157     else
 158       lua_pushstring(L, "dead");
 159   } else {
 160     lua_pushstring(L, "???");
 161   }
 162   return 1;
 163 }
 164
 165 int gr_collect(lua_State *L)
 166 {
 167   gr_object_t *ud = lua_touserdata(L, 1);
 168   TRACE("   gr_collect(): %s ud=%p ptr=%p\n", ud->p.name, ud, ud->p.p);
 169   if (ud->p.name)
 170     free(ud->p.name);
 171   ud->p.p = NULL;
 172   return 0;
 173 }
 174
 175 /*
 176  * Get an object from Lua registry.
 177  */
 178 int get_object(lua_State *L, void *key)
 179 {
 180   gr_object_t *ud;
 181   lua_pushlightuserdata(L, key);               /* ?, key */
 182   lua_rawget(L, LUA_REGISTRYINDEX);            /* ?, ud or nil */
 183   ud = lua_touserdata(L, -1);
 184   if (ud == NULL){
 185     TRACE("   get_object(): key = %p not found (%s %d)\n", key, __FILE__, __LINE__);
 186     lua_pushstring(L, "object not found in registry");            /* ?, nil, err */
 187     return 2;
 188   }
 189   TRACE("   get_object(): key=%p ud=%p '%s' (%s %d)\n", key, ud, ud->p.name, __FILE__,__LINE__);
 190   return 1;                                    /* ?, ud */
 191 }
 192
 193 /*
 194  * Get the value of a graphviz object attribute
 195  */
 196 int getval(lua_State *L)
 197 {
 198   gr_object_t *ud = toobject(L, 1, NULL, STRICT);
 199   char *key = (char *) luaL_checkstring(L, 2);
 200   char *value = agget(ud->p.p, key);
 201   if (!value || strlen(value) == 0){
 202     lua_pushnil(L);
 203     return 1;
 204   }
 205   lua_pushstring(L, value);
 206   return 1;
 207 }
 208
 209 /*
 210  * Set a value to a graphviz object attribute
 211  */
 212 static int setval(lua_State *L)
 213 {
 214   gr_object_t *ud = toobject(L, 1, NULL, STRICT);
 215   char *key = (char *) luaL_checkstring(L, 2);
 216   char *value = (char *) luaL_checkstring(L, 3);
 217   //  return agset(ud->p.p, key, value);
 218   return  agsafeset(ud->p.p, key, value, "");
 219 }
 220
 221 /*
 222  * Generic object index metamethod handler
 223  * This closure has 2 upvalues:
 224  * 1. table with read members (this is the metatable)
 225  * 2. metatable.__metatable contains the methods
 226  * Lua stack: ud, key
 227  */
 228 int object_index_handler(lua_State *L)
 229 {
 230   gr_object_t *ud;
 231   char *skey;
 232
 233   /* Read member lookup in first upvalue */
 234   lua_pushvalue(L, 2);                      /* ud, key, key */
 235   lua_rawget(L, lua_upvalueindex(1));       /* ud, key, getfunc (member) or nil (method) */
 236   if (!lua_isfunction(L, -1)){
 237     /* Member not found - try methods */
 238     lua_pop(L, 1);                          /* ud, key */
 239     lua_pushvalue(L, 2);                    /* ud, key, key */
 240     lua_gettable(L, lua_upvalueindex(2));   /* ud, key, method */
 241     if (lua_isnil(L, -1)){
 242       /* Try generic get method */
 243       if (lua_isstring(L, 2)){
 244         lua_settop(L, 2);                     /* ud, key */
 245         lua_pushcfunction(L, getval);         /* ud, key, gr_get */
 246         lua_pushvalue(L, 1);                  /* ud, key, gr_get, ud */
 247         lua_pushvalue(L, 2);                  /* ud, key, gr_get, ud, key */
 248         lua_call(L, 2, 1);                    /* ud, key, value or nil */
 249       }
 250       if (lua_isnil(L, -1)){
 251         /* Try generic storage */
 252         lua_settop(L, 2);                      /* ud, key */
 253         ud = toobject(L, 1, NULL, STRICT);
 254         skey = agget(ud->p.p, "__attrib__");
 255         if (skey && strlen(skey) > 0){
 256           lua_pushstring(L, skey);            /* ud, key, skey */
 257           lua_rawget(L, LUA_REGISTRYINDEX);   /* ud, key, stab */
 258           lua_pushvalue(L, 2);                /* ud, key, stab, key */
 259           lua_rawget(L, -2);                  /* ud, key, stab, value */
 260           lua_remove(L, -2);                  /* ud, key, value */
 261         } else
 262           lua_pushnil(L);                     /* ud, key, nil */
 263       }
 264     }
 265     return 1;
 266   }
 267   /* Call the member's access function */
 268   lua_pushvalue(L, 1);                      /* ud, key, getfunc, ud */
 269   lua_pushvalue(L, 2);                      /* ud, key, getfunc, ud, key */
 270   lua_call(L, 2, 1);                        /* ud, key, value */
 271   return 1;
 272 }
 273
 274 /*
 275  * Generic object newindex metamethod handler.
 276  * Lua Stack: ud, key, value
 277  */
 278 int object_newindex_handler(lua_State *L)
 279 {
 280   char sskey[16], *skey;
 281   TRACE("   newindex(): key='%s' value='%s'\n", lua_tostring(L, 2), lua_tostring(L, 3));
 282   if ((!lua_isstring(L, 2)) || (!lua_isstring(L, 3))){
 283     gr_object_t *ud = toobject(L, 1, NULL, STRICT);
 284     skey = agget(ud->p.p, "__attrib__");
 285     if (!skey || (strlen(skey) == 0)){
 286       /* Let's create an attrib table on the fly if none exists */
 287       sprintf(sskey, "%p", ud->p.p);
 288       skey = agstrdup(agroot(ud->p.p), sskey);
 289       agset(ud->p.p, "__attrib__", skey);
 290       lua_pushstring(L, skey);             /* ud, key, value, skey */
 291       lua_newtable(L);                     /* ud, key, value, skey, stab */
 292       lua_rawset(L, LUA_REGISTRYINDEX);    /* ud, key, value, */
 293     }
 294     lua_pushstring(L, skey);          /* ud, key, value, skey */
 295     lua_rawget(L, LUA_REGISTRYINDEX); /* ud, key, value, stab */
 296     lua_pushvalue(L, 2);              /* ud, key, value, stab, key */
 297     lua_pushvalue(L, 3);              /* ud, key, value, stab, key, value */
 298     lua_rawset(L, -3);                /* ud, key, value, stab */
 299     lua_pop(L, -1);                   /* ud, key, value */
 300     return 0;
 301   }
 302   return setval(L);
 303 }
 304
 305 /*
 306  * Create the graph object with member and method access.
 307  * Lua entry stack: ud
 308  * Lua exit stack:  ud
 309  */
 310 int new_object(lua_State *L, const char *kind, const luaL_Reg *reg_rmembers,
 311                const luaL_Reg *reg_methods, const luaL_Reg *reg_metamethods,
 312                index_handler_t *index_handler)
 313 {
 314   int methods, metatable;
 315   /* Put methods in a table */
 316   lua_newtable(L);                         /* ud, mtab */
 317
 318   register_metainfo(L, reg_methods);
 319   methods = lua_gettop(L);
 320
 321   /* Put metamethods in a new metatable */
 322   luaL_newmetatable(L, kind);             /* ud, mtab, mt */
 323
 324   register_metainfo(L, reg_metamethods);
 325   metatable = lua_gettop(L);
 326
 327   /* Keep a reference to methods in the new metatable */
 328   lua_pushstring(L, "__metatable");        /* ud, mtab, mt, "__metatable" */
 329   lua_pushvalue(L, methods);               /* ud, mtab, mt, "__metatable", mtab */
 330   lua_rawset(L, -3);                       /* ud, mtab, mt */
 331
 332   lua_pushstring(L, "__index");            /* ud, mtab, mt, "__index" */
 333
 334   /* First upvalue: metatable => members access */
 335   lua_pushvalue(L, metatable);             /* ud, mtab, mt, "__index", mt(upv 1) */
 336
 337   /* Put members into the metatable */
 338   register_metainfo(L, reg_rmembers);
 339
 340   /* Second upvalue, methods => methods access */
 341   lua_pushvalue(L, methods);              /* ud, mtab, mt, "__index", mt(upv 1), mtab(upv 2) */
 342
 343   /* Set index_handler with 2 upvalues as __index metamethod */
 344   lua_pushcclosure(L, index_handler, 2);  /* ud, mtab, mt, "__index", func */
 345   lua_rawset(L, metatable);               /* ud, mtab, mt */
 346
 347   lua_setmetatable(L, -3);           /* ud, mtab */
 348   lua_pop(L,1);                           /* ud */
 349
 350   return 1;
 351 }
 352
 353 /*
 354  * Check an object type.
 355  */
 356 void *chk_object(lua_State *L, void *obj)
 357 {
 358   gr_object_t *ud = (gr_object_t *) obj;
 359   if (ud->p.p == NULL){
 360     lua_pushfstring(L, "invalid userdata of type `%s' detected",
 361                     ud->p.type == AGRAPH ? "graph" :
 362                     ud->p.type == AGNODE ? "node" :
 363                     ud->p.type == AGEDGE ? "edge" : "unknown");
 364     lua_error(L);
 365     return NULL;
 366   }
 367   return obj;
 368 }
 369
 370 /*-------------------------------------------------------------------------*\
 371  * Generic method: type = obj.type(self)
 372  * Returns type of a graph object.
 373  * Returns the type as string: 'graph', 'node' or 'edge'.
 374  * Example:
 375  * type = n:type()
 376 \*-------------------------------------------------------------------------*/
 377 int get_object_type(lua_State *L)
 378 {
 379   gr_object_t *ud = toobject(L, 1, NULL, STRICT);
 380   lua_pushstring(L, AGTYPE(ud->p.p) == AGRAPH ? "graph" :
 381                  AGTYPE(ud->p.p) == AGNODE ? "node" :
 382                  AGTYPE(ud->p.p) == AGEDGE ? "edge" : "unkown");
 383   return 1;
 384 }
 385
 386
 387