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 G_DEFINE_BOXED_TYPE (GDateTime, g_date_time, g_date_time_ref, g_date_time_unref);
 144
 145 /* This one can't use G_DEFINE_BOXED_TYPE (GStrv, g_strv, g_strdupv, g_strfreev) */
 146 GType
 147 g_strv_get_type (void)
 148 {
 149   static volatile gsize g_define_type_id__volatile = 0;
 150
 151   if (g_once_init_enter (&g_define_type_id__volatile))
 152     {
 153       GType g_define_type_id =
 154         g_boxed_type_register_static (g_intern_static_string ("GStrv"),
 155                                       (GBoxedCopyFunc) g_strdupv,
 156                                       (GBoxedFreeFunc) g_strfreev);
 157
 158       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
 159     }
 160
 161   return g_define_type_id__volatile;
 162 }
 163
 164 /**
 165  * g_variant_get_gtype:
 166  *
 167  * Since: 2.24
 168  * Deprecated: 2.26
 169  */
 170 GType
 171 g_variant_get_gtype (void)
 172 {
 173   return G_TYPE_VARIANT;
 174 }
 175
 176 static void
 177 boxed_proxy_value_init (GValue *value)
 178 {
 179   value->data[0].v_pointer = NULL;
 180 }
 181
 182 static void
 183 boxed_proxy_value_free (GValue *value)
 184 {
 185   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 186     _g_type_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 187 }
 188
 189 static void
 190 boxed_proxy_value_copy (const GValue *src_value,
 191                         GValue       *dest_value)
 192 {
 193   if (src_value->data[0].v_pointer)
 194     dest_value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (src_value), src_value->data[0].v_pointer);
 195   else
 196     dest_value->data[0].v_pointer = src_value->data[0].v_pointer;
 197 }
 198
 199 static gpointer
 200 boxed_proxy_value_peek_pointer (const GValue *value)
 201 {
 202   return value->data[0].v_pointer;
 203 }
 204
 205 static gchar*
 206 boxed_proxy_collect_value (GValue      *value,
 207                            guint        n_collect_values,
 208                            GTypeCValue *collect_values,
 209                            guint        collect_flags)
 210 {
 211   if (!collect_values[0].v_pointer)
 212     value->data[0].v_pointer = NULL;
 213   else
 214     {
 215       if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 216         {
 217           value->data[0].v_pointer = collect_values[0].v_pointer;
 218           value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 219         }
 220       else
 221         value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (value), collect_values[0].v_pointer);
 222     }
 223
 224   return NULL;
 225 }
 226
 227 static gchar*
 228 boxed_proxy_lcopy_value (const GValue *value,
 229                          guint         n_collect_values,
 230                          GTypeCValue  *collect_values,
 231                          guint         collect_flags)
 232 {
 233   gpointer *boxed_p = collect_values[0].v_pointer;
 234
 235   if (!boxed_p)
 236     return g_strdup_printf ("value location for `%s' passed as NULL", G_VALUE_TYPE_NAME (value));
 237
 238   if (!value->data[0].v_pointer)
 239     *boxed_p = NULL;
 240   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 241     *boxed_p = value->data[0].v_pointer;
 242   else
 243     *boxed_p = _g_type_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer);
 244
 245   return NULL;
 246 }
 247
 248 /**
 249  * g_boxed_type_register_static:
 250  * @name: Name of the new boxed type.
 251  * @boxed_copy: Boxed structure copy function.
 252  * @boxed_free: Boxed structure free function.
 253  *
 254  * This function creates a new %G_TYPE_BOXED derived type id for a new
 255  * boxed type with name @name. Boxed type handling functions have to be
 256  * provided to copy and free opaque boxed structures of this type.
 257  *
 258  * Returns: New %G_TYPE_BOXED derived type id for @name.
 259  */
 260 GType
 261 g_boxed_type_register_static (const gchar   *name,
 262                               GBoxedCopyFunc boxed_copy,
 263                               GBoxedFreeFunc boxed_free)
 264 {
 265   static const GTypeValueTable vtable = {
 266     boxed_proxy_value_init,
 267     boxed_proxy_value_free,
 268     boxed_proxy_value_copy,
 269     boxed_proxy_value_peek_pointer,
 270     "p",
 271     boxed_proxy_collect_value,
 272     "p",
 273     boxed_proxy_lcopy_value,
 274   };
 275   GTypeInfo type_info = {
 276     0,                  /* class_size */
 277     NULL,               /* base_init */
 278     NULL,               /* base_finalize */
 279     NULL,               /* class_init */
 280     NULL,               /* class_finalize */
 281     NULL,               /* class_data */
 282     0,                  /* instance_size */
 283     0,                  /* n_preallocs */
 284     NULL,               /* instance_init */
 285     &vtable,            /* value_table */
 286   };
 287   GType type;
 288
 289   g_return_val_if_fail (name != NULL, 0);
 290   g_return_val_if_fail (boxed_copy != NULL, 0);
 291   g_return_val_if_fail (boxed_free != NULL, 0);
 292   g_return_val_if_fail (g_type_from_name (name) == 0, 0);
 293
 294   type = g_type_register_static (G_TYPE_BOXED, name, &type_info, 0);
 295
 296   /* install proxy functions upon successfull registration */
 297   if (type)
 298     _g_type_boxed_init (type, boxed_copy, boxed_free);
 299
 300   return type;
 301 }
 302
 303 /**
 304  * g_boxed_copy:
 305  * @boxed_type: The type of @src_boxed.
 306  * @src_boxed: The boxed structure to be copied.
 307  *
 308  * Provide a copy of a boxed structure @src_boxed which is of type @boxed_type.
 309  *
 310  * Returns: The newly created copy of the boxed structure.
 311  */
 312 gpointer
 313 g_boxed_copy (GType         boxed_type,
 314               gconstpointer src_boxed)
 315 {
 316   GTypeValueTable *value_table;
 317   gpointer dest_boxed;
 318
 319   g_return_val_if_fail (G_TYPE_IS_BOXED (boxed_type), NULL);
 320   g_return_val_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE, NULL);
 321   g_return_val_if_fail (src_boxed != NULL, NULL);
 322
 323   value_table = g_type_value_table_peek (boxed_type);
 324   if (!value_table)
 325     g_return_val_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type), NULL);
 326
 327   /* check if our proxying implementation is used, we can short-cut here */
 328   if (value_table->value_copy == boxed_proxy_value_copy)
 329     dest_boxed = _g_type_boxed_copy (boxed_type, (gpointer) src_boxed);
 330   else
 331     {
 332       GValue src_value, dest_value;
 333
 334       /* we heavily rely on third-party boxed type value vtable
 335        * implementations to follow normal boxed value storage
 336        * (data[0].v_pointer is the boxed struct, and
 337        * data[1].v_uint holds the G_VALUE_NOCOPY_CONTENTS flag,
 338        * rest zero).
 339        * but then, we can expect that since we layed out the
 340        * g_boxed_*() API.
 341        * data[1].v_uint&G_VALUE_NOCOPY_CONTENTS shouldn't be set
 342        * after a copy.
 343        */
 344       /* equiv. to g_value_set_static_boxed() */
 345       value_meminit (&src_value, boxed_type);
 346       src_value.data[0].v_pointer = (gpointer) src_boxed;
 347       src_value.data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 348
 349       /* call third-party code copy function, fingers-crossed */
 350       value_meminit (&dest_value, boxed_type);
 351       value_table->value_copy (&src_value, &dest_value);
 352
 353       /* double check and grouse if things went wrong */
 354       if (dest_value.data[1].v_ulong)
 355         g_warning ("the copy_value() implementation of type `%s' seems to make use of reserved GValue fields",
 356                    g_type_name (boxed_type));
 357
 358       dest_boxed = dest_value.data[0].v_pointer;
 359     }
 360
 361   return dest_boxed;
 362 }
 363
 364 /**
 365  * g_boxed_free:
 366  * @boxed_type: The type of @boxed.
 367  * @boxed: The boxed structure to be freed.
 368  *
 369  * Free the boxed structure @boxed which is of type @boxed_type.
 370  */
 371 void
 372 g_boxed_free (GType    boxed_type,
 373               gpointer boxed)
 374 {
 375   GTypeValueTable *value_table;
 376
 377   g_return_if_fail (G_TYPE_IS_BOXED (boxed_type));
 378   g_return_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE);
 379   g_return_if_fail (boxed != NULL);
 380
 381   value_table = g_type_value_table_peek (boxed_type);
 382   if (!value_table)
 383     g_return_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type));
 384
 385   /* check if our proxying implementation is used, we can short-cut here */
 386   if (value_table->value_free == boxed_proxy_value_free)
 387     _g_type_boxed_free (boxed_type, boxed);
 388   else
 389     {
 390       GValue value;
 391
 392       /* see g_boxed_copy() on why we think we can do this */
 393       value_meminit (&value, boxed_type);
 394       value.data[0].v_pointer = boxed;
 395       value_table->value_free (&value);
 396     }
 397 }
 398
 399 /**
 400  * g_value_get_boxed:
 401  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 402  *
 403  * Get the contents of a %G_TYPE_BOXED derived #GValue.
 404  *
 405  * Returns: (transfer none): boxed contents of @value
 406  */
 407 gpointer
 408 g_value_get_boxed (const GValue *value)
 409 {
 410   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 411   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 412
 413   return value->data[0].v_pointer;
 414 }
 415
 416 /**
 417  * g_value_dup_boxed: (skip)
 418  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 419  *
 420  * Get the contents of a %G_TYPE_BOXED derived #GValue.  Upon getting,
 421  * the boxed value is duplicated and needs to be later freed with
 422  * g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (@value),
 423  * return_value);
 424  *
 425  * Returns: boxed contents of @value
 426  */
 427 gpointer
 428 g_value_dup_boxed (const GValue *value)
 429 {
 430   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 431   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 432
 433   return value->data[0].v_pointer ? g_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer) : NULL;
 434 }
 435
 436 static inline void
 437 value_set_boxed_internal (GValue       *value,
 438                           gconstpointer boxed,
 439                           gboolean      need_copy,
 440                           gboolean      need_free)
 441 {
 442   if (!boxed)
 443     {
 444       /* just resetting to NULL might not be desired, need to
 445        * have value reinitialized also (for values defaulting
 446        * to other default value states than a NULL data pointer),
 447        * g_value_reset() will handle this
 448        */
 449       g_value_reset (value);
 450       return;
 451     }
 452
 453   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 454     g_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 455   value->data[1].v_uint = need_free ? 0 : G_VALUE_NOCOPY_CONTENTS;
 456   value->data[0].v_pointer = need_copy ? g_boxed_copy (G_VALUE_TYPE (value), boxed) : (gpointer) boxed;
 457 }
 458
 459 /**
 460  * g_value_set_boxed:
 461  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 462  * @v_boxed: boxed value to be set
 463  *
 464  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 465  */
 466 void
 467 g_value_set_boxed (GValue       *value,
 468                    gconstpointer boxed)
 469 {
 470   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 471   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 472
 473   value_set_boxed_internal (value, boxed, TRUE, TRUE);
 474 }
 475
 476 /**
 477  * g_value_set_static_boxed:
 478  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 479  * @v_boxed: static boxed value to be set
 480  *
 481  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 482  * The boxed value is assumed to be static, and is thus not duplicated
 483  * when setting the #GValue.
 484  */
 485 void
 486 g_value_set_static_boxed (GValue       *value,
 487                           gconstpointer boxed)
 488 {
 489   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 490   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 491
 492   value_set_boxed_internal (value, boxed, FALSE, FALSE);
 493 }
 494
 495 /**
 496  * g_value_set_boxed_take_ownership:
 497  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 498  * @v_boxed: duplicated unowned boxed value to be set
 499  *
 500  * This is an internal function introduced mainly for C marshallers.
 501  *
 502  * Deprecated: 2.4: Use g_value_take_boxed() instead.
 503  */
 504 void
 505 g_value_set_boxed_take_ownership (GValue       *value,
 506                                   gconstpointer boxed)
 507 {
 508   g_value_take_boxed (value, boxed);
 509 }
 510
 511 /**
 512  * g_value_take_boxed:
 513  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 514  * @v_boxed: duplicated unowned boxed value to be set
 515  *
 516  * Sets the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed
 517  * and takes over the ownership of the callers reference to @v_boxed;
 518  * the caller doesn't have to unref it any more.
 519  *
 520  * Since: 2.4
 521  */
 522 void
 523 g_value_take_boxed (GValue       *value,
 524                     gconstpointer boxed)
 525 {
 526   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 527   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 528
 529   value_set_boxed_internal (value, boxed, FALSE, TRUE);
 530 }