gobject/gboxed.c

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 2000-2001 Red Hat, Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General
  15  * Public License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 #include "config.h"
  21
  22 #include <string.h>
  23
  24 #include "gboxed.h"
  25 #include "gtype-private.h"
  26 #include "gvalue.h"
  27 #include "gvaluearray.h"
  28 #include "gclosure.h"
  29 #include "gvaluecollector.h"
  30
  31
  32 /**
  33  * SECTION:gboxed
  34  * @short_description: A mechanism to wrap opaque C structures registered
  35  *     by the type system
  36  * @see_also: #GParamSpecBoxed, g_param_spec_boxed()
  37  * @title: Boxed Types
  38  *
  39  * GBoxed is a generic wrapper mechanism for arbitrary C structures. The only
  40  * thing the type system needs to know about the structures is how to copy and
  41  * free them, beyond that they are treated as opaque chunks of memory.
  42  *
  43  * Boxed types are useful for simple value-holder structures like rectangles or
  44  * points. They can also be used for wrapping structures defined in non-GObject
  45  * based libraries.
  46  */
  47
  48 static inline void              /* keep this function in sync with gvalue.c */
  49 value_meminit (GValue *value,
  50                GType   value_type)
  51 {
  52   value->g_type = value_type;
  53   memset (value->data, 0, sizeof (value->data));
  54 }
  55
  56 static GValue *
  57 value_copy (GValue *src_value)
  58 {
  59   GValue *dest_value = g_new0 (GValue, 1);
  60
  61   if (G_VALUE_TYPE (src_value))
  62     {
  63       g_value_init (dest_value, G_VALUE_TYPE (src_value));
  64       g_value_copy (src_value, dest_value);
  65     }
  66   return dest_value;
  67 }
  68
  69 static void
  70 value_free (GValue *value)
  71 {
  72   if (G_VALUE_TYPE (value))
  73     g_value_unset (value);
  74   g_free (value);
  75 }
  76
  77 void
  78 g_boxed_type_init (void)
  79 {
  80   static const GTypeInfo info = {
  81     0,                          /* class_size */
  82     NULL,                       /* base_init */
  83     NULL,                       /* base_destroy */
  84     NULL,                       /* class_init */
  85     NULL,                       /* class_destroy */
  86     NULL,                       /* class_data */
  87     0,                          /* instance_size */
  88     0,                          /* n_preallocs */
  89     NULL,                       /* instance_init */
  90     NULL,                       /* value_table */
  91   };
  92   const GTypeFundamentalInfo finfo = { G_TYPE_FLAG_DERIVABLE, };
  93   GType type;
  94
  95   /* G_TYPE_BOXED
  96    */
  97   type = g_type_register_fundamental (G_TYPE_BOXED, g_intern_static_string ("GBoxed"), &info, &finfo,
  98                                       G_TYPE_FLAG_ABSTRACT | G_TYPE_FLAG_VALUE_ABSTRACT);
  99   g_assert (type == G_TYPE_BOXED);
 100 }
 101
 102 static GDate *
 103 gdate_copy (GDate *date)
 104 {
 105   return g_date_new_julian (g_date_get_julian (date));
 106 }
 107
 108 static GString *
 109 gstring_copy (GString *src_gstring)
 110 {
 111   return g_string_new_len (src_gstring->str, src_gstring->len);
 112 }
 113
 114 static void
 115 gstring_free (GString *gstring)
 116 {
 117   g_string_free (gstring, TRUE);
 118 }
 119
 120 G_DEFINE_BOXED_TYPE (GClosure, g_closure, g_closure_ref, g_closure_unref)
 121 G_DEFINE_BOXED_TYPE (GValue, g_value, value_copy, value_free)
 122 G_DEFINE_BOXED_TYPE (GValueArray, g_value_array, g_value_array_copy, g_value_array_free)
 123 G_DEFINE_BOXED_TYPE (GDate, g_date, gdate_copy, g_date_free)
 124 /* the naming is a bit odd, but GString is obviously not G_TYPE_STRING */
 125 G_DEFINE_BOXED_TYPE (GString, g_gstring, gstring_copy, gstring_free)
 126 G_DEFINE_BOXED_TYPE (GHashTable, g_hash_table, g_hash_table_ref, g_hash_table_unref)
 127 G_DEFINE_BOXED_TYPE (GArray, g_array, g_array_ref, g_array_unref)
 128 G_DEFINE_BOXED_TYPE (GPtrArray, g_ptr_array,g_ptr_array_ref, g_ptr_array_unref)
 129 G_DEFINE_BOXED_TYPE (GByteArray, g_byte_array, g_byte_array_ref, g_byte_array_unref)
 130
 131 #ifdef ENABLE_REGEX
 132 G_DEFINE_BOXED_TYPE (GRegex, g_regex, g_regex_ref, g_regex_unref)
 133 #else
 134 GType g_regex_get_type (void) { return G_TYPE_INVALID; }
 135 #endif /* ENABLE_REGEX */
 136
 137 #define g_variant_type_get_type g_variant_type_get_gtype
 138 G_DEFINE_BOXED_TYPE (GVariantType, g_variant_type, g_variant_type_copy, g_variant_type_free)
 139 #undef g_variant_type_get_type
 140
 141 G_DEFINE_BOXED_TYPE (GError, g_error, g_error_copy, g_error_free)
 142
 143 /* This one can't use G_DEFINE_BOXED_TYPE (GStrv, g_strv, g_strdupv, g_strfreev) */
 144 GType
 145 g_strv_get_type (void)
 146 {
 147   static volatile gsize g_define_type_id__volatile = 0;
 148
 149   if (g_once_init_enter (&g_define_type_id__volatile))
 150     {
 151       GType g_define_type_id =
 152         g_boxed_type_register_static (g_intern_static_string ("GStrv"),
 153                                       (GBoxedCopyFunc) g_strdupv,
 154                                       (GBoxedFreeFunc) g_strfreev);
 155
 156       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
 157     }
 158
 159   return g_define_type_id__volatile;
 160 }
 161
 162 /**
 163  * g_variant_get_gtype:
 164  *
 165  * Since: 2.24
 166  * Deprecated: 2.26
 167  */
 168 GType
 169 g_variant_get_gtype (void)
 170 {
 171   return G_TYPE_VARIANT;
 172 }
 173
 174 static void
 175 boxed_proxy_value_init (GValue *value)
 176 {
 177   value->data[0].v_pointer = NULL;
 178 }
 179
 180 static void
 181 boxed_proxy_value_free (GValue *value)
 182 {
 183   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 184     _g_type_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 185 }
 186
 187 static void
 188 boxed_proxy_value_copy (const GValue *src_value,
 189                         GValue       *dest_value)
 190 {
 191   if (src_value->data[0].v_pointer)
 192     dest_value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (src_value), src_value->data[0].v_pointer);
 193   else
 194     dest_value->data[0].v_pointer = src_value->data[0].v_pointer;
 195 }
 196
 197 static gpointer
 198 boxed_proxy_value_peek_pointer (const GValue *value)
 199 {
 200   return value->data[0].v_pointer;
 201 }
 202
 203 static gchar*
 204 boxed_proxy_collect_value (GValue      *value,
 205                            guint        n_collect_values,
 206                            GTypeCValue *collect_values,
 207                            guint        collect_flags)
 208 {
 209   if (!collect_values[0].v_pointer)
 210     value->data[0].v_pointer = NULL;
 211   else
 212     {
 213       if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 214         {
 215           value->data[0].v_pointer = collect_values[0].v_pointer;
 216           value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 217         }
 218       else
 219         value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (value), collect_values[0].v_pointer);
 220     }
 221
 222   return NULL;
 223 }
 224
 225 static gchar*
 226 boxed_proxy_lcopy_value (const GValue *value,
 227                          guint         n_collect_values,
 228                          GTypeCValue  *collect_values,
 229                          guint         collect_flags)
 230 {
 231   gpointer *boxed_p = collect_values[0].v_pointer;
 232
 233   if (!boxed_p)
 234     return g_strdup_printf ("value location for `%s' passed as NULL", G_VALUE_TYPE_NAME (value));
 235
 236   if (!value->data[0].v_pointer)
 237     *boxed_p = NULL;
 238   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 239     *boxed_p = value->data[0].v_pointer;
 240   else
 241     *boxed_p = _g_type_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer);
 242
 243   return NULL;
 244 }
 245
 246 /**
 247  * g_boxed_type_register_static:
 248  * @name: Name of the new boxed type.
 249  * @boxed_copy: Boxed structure copy function.
 250  * @boxed_free: Boxed structure free function.
 251  *
 252  * This function creates a new %G_TYPE_BOXED derived type id for a new
 253  * boxed type with name @name. Boxed type handling functions have to be
 254  * provided to copy and free opaque boxed structures of this type.
 255  *
 256  * Returns: New %G_TYPE_BOXED derived type id for @name.
 257  */
 258 GType
 259 g_boxed_type_register_static (const gchar   *name,
 260                               GBoxedCopyFunc boxed_copy,
 261                               GBoxedFreeFunc boxed_free)
 262 {
 263   static const GTypeValueTable vtable = {
 264     boxed_proxy_value_init,
 265     boxed_proxy_value_free,
 266     boxed_proxy_value_copy,
 267     boxed_proxy_value_peek_pointer,
 268     "p",
 269     boxed_proxy_collect_value,
 270     "p",
 271     boxed_proxy_lcopy_value,
 272   };
 273   GTypeInfo type_info = {
 274     0,                  /* class_size */
 275     NULL,               /* base_init */
 276     NULL,               /* base_finalize */
 277     NULL,               /* class_init */
 278     NULL,               /* class_finalize */
 279     NULL,               /* class_data */
 280     0,                  /* instance_size */
 281     0,                  /* n_preallocs */
 282     NULL,               /* instance_init */
 283     &vtable,            /* value_table */
 284   };
 285   GType type;
 286
 287   g_return_val_if_fail (name != NULL, 0);
 288   g_return_val_if_fail (boxed_copy != NULL, 0);
 289   g_return_val_if_fail (boxed_free != NULL, 0);
 290   g_return_val_if_fail (g_type_from_name (name) == 0, 0);
 291
 292   type = g_type_register_static (G_TYPE_BOXED, name, &type_info, 0);
 293
 294   /* install proxy functions upon successfull registration */
 295   if (type)
 296     _g_type_boxed_init (type, boxed_copy, boxed_free);
 297
 298   return type;
 299 }
 300
 301 /**
 302  * g_boxed_copy:
 303  * @boxed_type: The type of @src_boxed.
 304  * @src_boxed: The boxed structure to be copied.
 305  *
 306  * Provide a copy of a boxed structure @src_boxed which is of type @boxed_type.
 307  *
 308  * Returns: The newly created copy of the boxed structure.
 309  */
 310 gpointer
 311 g_boxed_copy (GType         boxed_type,
 312               gconstpointer src_boxed)
 313 {
 314   GTypeValueTable *value_table;
 315   gpointer dest_boxed;
 316
 317   g_return_val_if_fail (G_TYPE_IS_BOXED (boxed_type), NULL);
 318   g_return_val_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE, NULL);
 319   g_return_val_if_fail (src_boxed != NULL, NULL);
 320
 321   value_table = g_type_value_table_peek (boxed_type);
 322   if (!value_table)
 323     g_return_val_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type), NULL);
 324
 325   /* check if our proxying implementation is used, we can short-cut here */
 326   if (value_table->value_copy == boxed_proxy_value_copy)
 327     dest_boxed = _g_type_boxed_copy (boxed_type, (gpointer) src_boxed);
 328   else
 329     {
 330       GValue src_value, dest_value;
 331
 332       /* we heavily rely on third-party boxed type value vtable
 333        * implementations to follow normal boxed value storage
 334        * (data[0].v_pointer is the boxed struct, and
 335        * data[1].v_uint holds the G_VALUE_NOCOPY_CONTENTS flag,
 336        * rest zero).
 337        * but then, we can expect that since we layed out the
 338        * g_boxed_*() API.
 339        * data[1].v_uint&G_VALUE_NOCOPY_CONTENTS shouldn't be set
 340        * after a copy.
 341        */
 342       /* equiv. to g_value_set_static_boxed() */
 343       value_meminit (&src_value, boxed_type);
 344       src_value.data[0].v_pointer = (gpointer) src_boxed;
 345       src_value.data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 346
 347       /* call third-party code copy function, fingers-crossed */
 348       value_meminit (&dest_value, boxed_type);
 349       value_table->value_copy (&src_value, &dest_value);
 350
 351       /* double check and grouse if things went wrong */
 352       if (dest_value.data[1].v_ulong)
 353         g_warning ("the copy_value() implementation of type `%s' seems to make use of reserved GValue fields",
 354                    g_type_name (boxed_type));
 355
 356       dest_boxed = dest_value.data[0].v_pointer;
 357     }
 358
 359   return dest_boxed;
 360 }
 361
 362 /**
 363  * g_boxed_free:
 364  * @boxed_type: The type of @boxed.
 365  * @boxed: The boxed structure to be freed.
 366  *
 367  * Free the boxed structure @boxed which is of type @boxed_type.
 368  */
 369 void
 370 g_boxed_free (GType    boxed_type,
 371               gpointer boxed)
 372 {
 373   GTypeValueTable *value_table;
 374
 375   g_return_if_fail (G_TYPE_IS_BOXED (boxed_type));
 376   g_return_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE);
 377   g_return_if_fail (boxed != NULL);
 378
 379   value_table = g_type_value_table_peek (boxed_type);
 380   if (!value_table)
 381     g_return_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type));
 382
 383   /* check if our proxying implementation is used, we can short-cut here */
 384   if (value_table->value_free == boxed_proxy_value_free)
 385     _g_type_boxed_free (boxed_type, boxed);
 386   else
 387     {
 388       GValue value;
 389
 390       /* see g_boxed_copy() on why we think we can do this */
 391       value_meminit (&value, boxed_type);
 392       value.data[0].v_pointer = boxed;
 393       value_table->value_free (&value);
 394     }
 395 }
 396
 397 /**
 398  * g_value_get_boxed:
 399  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 400  *
 401  * Get the contents of a %G_TYPE_BOXED derived #GValue.
 402  *
 403  * Returns: boxed contents of @value
 404  */
 405 gpointer
 406 g_value_get_boxed (const GValue *value)
 407 {
 408   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 409   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 410
 411   return value->data[0].v_pointer;
 412 }
 413
 414 /**
 415  * g_value_dup_boxed:
 416  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 417  *
 418  * Get the contents of a %G_TYPE_BOXED derived #GValue.  Upon getting,
 419  * the boxed value is duplicated and needs to be later freed with
 420  * g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (@value),
 421  * return_value);
 422  *
 423  * Returns: boxed contents of @value
 424  */
 425 gpointer
 426 g_value_dup_boxed (const GValue *value)
 427 {
 428   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 429   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 430
 431   return value->data[0].v_pointer ? g_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer) : NULL;
 432 }
 433
 434 static inline void
 435 value_set_boxed_internal (GValue       *value,
 436                           gconstpointer boxed,
 437                           gboolean      need_copy,
 438                           gboolean      need_free)
 439 {
 440   if (!boxed)
 441     {
 442       /* just resetting to NULL might not be desired, need to
 443        * have value reinitialized also (for values defaulting
 444        * to other default value states than a NULL data pointer),
 445        * g_value_reset() will handle this
 446        */
 447       g_value_reset (value);
 448       return;
 449     }
 450
 451   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 452     g_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 453   value->data[1].v_uint = need_free ? 0 : G_VALUE_NOCOPY_CONTENTS;
 454   value->data[0].v_pointer = need_copy ? g_boxed_copy (G_VALUE_TYPE (value), boxed) : (gpointer) boxed;
 455 }
 456
 457 /**
 458  * g_value_set_boxed:
 459  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 460  * @v_boxed: boxed value to be set
 461  *
 462  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 463  */
 464 void
 465 g_value_set_boxed (GValue       *value,
 466                    gconstpointer boxed)
 467 {
 468   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 469   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 470
 471   value_set_boxed_internal (value, boxed, TRUE, TRUE);
 472 }
 473
 474 /**
 475  * g_value_set_static_boxed:
 476  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 477  * @v_boxed: static boxed value to be set
 478  *
 479  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 480  * The boxed value is assumed to be static, and is thus not duplicated
 481  * when setting the #GValue.
 482  */
 483 void
 484 g_value_set_static_boxed (GValue       *value,
 485                           gconstpointer boxed)
 486 {
 487   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 488   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 489
 490   value_set_boxed_internal (value, boxed, FALSE, FALSE);
 491 }
 492
 493 /**
 494  * g_value_set_boxed_take_ownership:
 495  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 496  * @v_boxed: duplicated unowned boxed value to be set
 497  *
 498  * This is an internal function introduced mainly for C marshallers.
 499  *
 500  * Deprecated: 2.4: Use g_value_take_boxed() instead.
 501  */
 502 void
 503 g_value_set_boxed_take_ownership (GValue       *value,
 504                                   gconstpointer boxed)
 505 {
 506   g_value_take_boxed (value, boxed);
 507 }
 508
 509 /**
 510  * g_value_take_boxed:
 511  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 512  * @v_boxed: duplicated unowned boxed value to be set
 513  *
 514  * Sets the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed
 515  * and takes over the ownership of the callers reference to @v_boxed;
 516  * the caller doesn't have to unref it any more.
 517  *
 518  * Since: 2.4
 519  */
 520 void
 521 g_value_take_boxed (GValue       *value,
 522                     gconstpointer boxed)
 523 {
 524   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 525   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 526
 527   value_set_boxed_internal (value, boxed, FALSE, TRUE);
 528 }