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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "config.h"
  19
  20 #include <string.h>
  21
  22 /* for GValueArray */
  23 #define GLIB_DISABLE_DEPRECATION_WARNINGS
  24
  25 #include "gboxed.h"
  26 #include "gclosure.h"
  27 #include "gtype-private.h"
  28 #include "gvalue.h"
  29 #include "gvaluearray.h"
  30 #include "gvaluecollector.h"
  31
  32
  33 /**
  34  * SECTION:gboxed
  35  * @short_description: A mechanism to wrap opaque C structures registered
  36  *     by the type system
  37  * @see_also: #GParamSpecBoxed, g_param_spec_boxed()
  38  * @title: Boxed Types
  39  *
  40  * GBoxed is a generic wrapper mechanism for arbitrary C structures. The only
  41  * thing the type system needs to know about the structures is how to copy and
  42  * free them, beyond that they are treated as opaque chunks of memory.
  43  *
  44  * Boxed types are useful for simple value-holder structures like rectangles or
  45  * points. They can also be used for wrapping structures defined in non-GObject
  46  * based libraries.
  47  */
  48
  49 static inline void              /* keep this function in sync with gvalue.c */
  50 value_meminit (GValue *value,
  51                GType   value_type)
  52 {
  53   value->g_type = value_type;
  54   memset (value->data, 0, sizeof (value->data));
  55 }
  56
  57 static GValue *
  58 value_copy (GValue *src_value)
  59 {
  60   GValue *dest_value = g_new0 (GValue, 1);
  61
  62   if (G_VALUE_TYPE (src_value))
  63     {
  64       g_value_init (dest_value, G_VALUE_TYPE (src_value));
  65       g_value_copy (src_value, dest_value);
  66     }
  67   return dest_value;
  68 }
  69
  70 static void
  71 value_free (GValue *value)
  72 {
  73   if (G_VALUE_TYPE (value))
  74     g_value_unset (value);
  75   g_free (value);
  76 }
  77
  78 static GPollFD *
  79 pollfd_copy (GPollFD *src)
  80 {
  81   GPollFD *dest = g_new0 (GPollFD, 1);
  82   /* just a couple of integers */
  83   memcpy (dest, src, sizeof (GPollFD));
  84   return dest;
  85 }
  86
  87 void
  88 _g_boxed_type_init (void)
  89 {
  90   const GTypeInfo info = {
  91     0,                          /* class_size */
  92     NULL,                       /* base_init */
  93     NULL,                       /* base_destroy */
  94     NULL,                       /* class_init */
  95     NULL,                       /* class_destroy */
  96     NULL,                       /* class_data */
  97     0,                          /* instance_size */
  98     0,                          /* n_preallocs */
  99     NULL,                       /* instance_init */
 100     NULL,                       /* value_table */
 101   };
 102   const GTypeFundamentalInfo finfo = { G_TYPE_FLAG_DERIVABLE, };
 103   GType type;
 104
 105   /* G_TYPE_BOXED
 106    */
 107   type = g_type_register_fundamental (G_TYPE_BOXED, g_intern_static_string ("GBoxed"), &info, &finfo,
 108                                       G_TYPE_FLAG_ABSTRACT | G_TYPE_FLAG_VALUE_ABSTRACT);
 109   g_assert (type == G_TYPE_BOXED);
 110 }
 111
 112 static GDate *
 113 gdate_copy (GDate *date)
 114 {
 115   return g_date_new_julian (g_date_get_julian (date));
 116 }
 117
 118 static GString *
 119 gstring_copy (GString *src_gstring)
 120 {
 121   return g_string_new_len (src_gstring->str, src_gstring->len);
 122 }
 123
 124 static void
 125 gstring_free (GString *gstring)
 126 {
 127   g_string_free (gstring, TRUE);
 128 }
 129
 130 G_DEFINE_BOXED_TYPE (GClosure, g_closure, g_closure_ref, g_closure_unref)
 131 G_DEFINE_BOXED_TYPE (GValue, g_value, value_copy, value_free)
 132 G_DEFINE_BOXED_TYPE (GValueArray, g_value_array, g_value_array_copy, g_value_array_free)
 133 G_DEFINE_BOXED_TYPE (GDate, g_date, gdate_copy, g_date_free)
 134 /* the naming is a bit odd, but GString is obviously not G_TYPE_STRING */
 135 G_DEFINE_BOXED_TYPE (GString, g_gstring, gstring_copy, gstring_free)
 136 G_DEFINE_BOXED_TYPE (GHashTable, g_hash_table, g_hash_table_ref, g_hash_table_unref)
 137 G_DEFINE_BOXED_TYPE (GArray, g_array, g_array_ref, g_array_unref)
 138 G_DEFINE_BOXED_TYPE (GPtrArray, g_ptr_array,g_ptr_array_ref, g_ptr_array_unref)
 139 G_DEFINE_BOXED_TYPE (GByteArray, g_byte_array, g_byte_array_ref, g_byte_array_unref)
 140 G_DEFINE_BOXED_TYPE (GBytes, g_bytes, g_bytes_ref, g_bytes_unref);
 141
 142 G_DEFINE_BOXED_TYPE (GRegex, g_regex, g_regex_ref, g_regex_unref)
 143 G_DEFINE_BOXED_TYPE (GMatchInfo, g_match_info, g_match_info_ref, g_match_info_unref)
 144
 145 #define g_variant_type_get_type g_variant_type_get_gtype
 146 G_DEFINE_BOXED_TYPE (GVariantType, g_variant_type, g_variant_type_copy, g_variant_type_free)
 147 #undef g_variant_type_get_type
 148
 149 G_DEFINE_BOXED_TYPE (GVariantBuilder, g_variant_builder, g_variant_builder_ref, g_variant_builder_unref)
 150 G_DEFINE_BOXED_TYPE (GVariantDict, g_variant_dict, g_variant_dict_ref, g_variant_dict_unref)
 151
 152 G_DEFINE_BOXED_TYPE (GError, g_error, g_error_copy, g_error_free)
 153
 154 G_DEFINE_BOXED_TYPE (GDateTime, g_date_time, g_date_time_ref, g_date_time_unref);
 155 G_DEFINE_BOXED_TYPE (GTimeZone, g_time_zone, g_time_zone_ref, g_time_zone_unref);
 156 G_DEFINE_BOXED_TYPE (GKeyFile, g_key_file, g_key_file_ref, g_key_file_unref)
 157 G_DEFINE_BOXED_TYPE (GMappedFile, g_mapped_file, g_mapped_file_ref, g_mapped_file_unref)
 158
 159 G_DEFINE_BOXED_TYPE (GMainLoop, g_main_loop, g_main_loop_ref, g_main_loop_unref)
 160 G_DEFINE_BOXED_TYPE (GMainContext, g_main_context, g_main_context_ref, g_main_context_unref)
 161 G_DEFINE_BOXED_TYPE (GSource, g_source, g_source_ref, g_source_unref)
 162 G_DEFINE_BOXED_TYPE (GPollFD, g_pollfd, pollfd_copy, g_free)
 163 G_DEFINE_BOXED_TYPE (GMarkupParseContext, g_markup_parse_context, g_markup_parse_context_ref, g_markup_parse_context_unref)
 164
 165 G_DEFINE_BOXED_TYPE (GThread, g_thread, g_thread_ref, g_thread_unref)
 166 G_DEFINE_BOXED_TYPE (GChecksum, g_checksum, g_checksum_copy, g_checksum_free)
 167
 168 G_DEFINE_BOXED_TYPE (GOptionGroup, g_option_group, g_option_group_ref, g_option_group_unref)
 169
 170 /* This one can't use G_DEFINE_BOXED_TYPE (GStrv, g_strv, g_strdupv, g_strfreev) */
 171 GType
 172 g_strv_get_type (void)
 173 {
 174   static volatile gsize g_define_type_id__volatile = 0;
 175
 176   if (g_once_init_enter (&g_define_type_id__volatile))
 177     {
 178       GType g_define_type_id =
 179         g_boxed_type_register_static (g_intern_static_string ("GStrv"),
 180                                       (GBoxedCopyFunc) g_strdupv,
 181                                       (GBoxedFreeFunc) g_strfreev);
 182
 183       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
 184     }
 185
 186   return g_define_type_id__volatile;
 187 }
 188
 189 GType
 190 g_variant_get_gtype (void)
 191 {
 192   return G_TYPE_VARIANT;
 193 }
 194
 195 static void
 196 boxed_proxy_value_init (GValue *value)
 197 {
 198   value->data[0].v_pointer = NULL;
 199 }
 200
 201 static void
 202 boxed_proxy_value_free (GValue *value)
 203 {
 204   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 205     _g_type_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 206 }
 207
 208 static void
 209 boxed_proxy_value_copy (const GValue *src_value,
 210                         GValue       *dest_value)
 211 {
 212   if (src_value->data[0].v_pointer)
 213     dest_value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (src_value), src_value->data[0].v_pointer);
 214   else
 215     dest_value->data[0].v_pointer = src_value->data[0].v_pointer;
 216 }
 217
 218 static gpointer
 219 boxed_proxy_value_peek_pointer (const GValue *value)
 220 {
 221   return value->data[0].v_pointer;
 222 }
 223
 224 static gchar*
 225 boxed_proxy_collect_value (GValue      *value,
 226                            guint        n_collect_values,
 227                            GTypeCValue *collect_values,
 228                            guint        collect_flags)
 229 {
 230   if (!collect_values[0].v_pointer)
 231     value->data[0].v_pointer = NULL;
 232   else
 233     {
 234       if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 235         {
 236           value->data[0].v_pointer = collect_values[0].v_pointer;
 237           value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 238         }
 239       else
 240         value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (value), collect_values[0].v_pointer);
 241     }
 242
 243   return NULL;
 244 }
 245
 246 static gchar*
 247 boxed_proxy_lcopy_value (const GValue *value,
 248                          guint         n_collect_values,
 249                          GTypeCValue  *collect_values,
 250                          guint         collect_flags)
 251 {
 252   gpointer *boxed_p = collect_values[0].v_pointer;
 253
 254   if (!boxed_p)
 255     return g_strdup_printf ("value location for '%s' passed as NULL", G_VALUE_TYPE_NAME (value));
 256
 257   if (!value->data[0].v_pointer)
 258     *boxed_p = NULL;
 259   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 260     *boxed_p = value->data[0].v_pointer;
 261   else
 262     *boxed_p = _g_type_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer);
 263
 264   return NULL;
 265 }
 266
 267 /**
 268  * g_boxed_type_register_static:
 269  * @name: Name of the new boxed type.
 270  * @boxed_copy: Boxed structure copy function.
 271  * @boxed_free: Boxed structure free function.
 272  *
 273  * This function creates a new %G_TYPE_BOXED derived type id for a new
 274  * boxed type with name @name. Boxed type handling functions have to be
 275  * provided to copy and free opaque boxed structures of this type.
 276  *
 277  * Returns: New %G_TYPE_BOXED derived type id for @name.
 278  */
 279 GType
 280 g_boxed_type_register_static (const gchar   *name,
 281                               GBoxedCopyFunc boxed_copy,
 282                               GBoxedFreeFunc boxed_free)
 283 {
 284   static const GTypeValueTable vtable = {
 285     boxed_proxy_value_init,
 286     boxed_proxy_value_free,
 287     boxed_proxy_value_copy,
 288     boxed_proxy_value_peek_pointer,
 289     "p",
 290     boxed_proxy_collect_value,
 291     "p",
 292     boxed_proxy_lcopy_value,
 293   };
 294   GTypeInfo type_info = {
 295     0,                  /* class_size */
 296     NULL,               /* base_init */
 297     NULL,               /* base_finalize */
 298     NULL,               /* class_init */
 299     NULL,               /* class_finalize */
 300     NULL,               /* class_data */
 301     0,                  /* instance_size */
 302     0,                  /* n_preallocs */
 303     NULL,               /* instance_init */
 304     &vtable,            /* value_table */
 305   };
 306   GType type;
 307
 308   g_return_val_if_fail (name != NULL, 0);
 309   g_return_val_if_fail (boxed_copy != NULL, 0);
 310   g_return_val_if_fail (boxed_free != NULL, 0);
 311   g_return_val_if_fail (g_type_from_name (name) == 0, 0);
 312
 313   type = g_type_register_static (G_TYPE_BOXED, name, &type_info, 0);
 314
 315   /* install proxy functions upon successful registration */
 316   if (type)
 317     _g_type_boxed_init (type, boxed_copy, boxed_free);
 318
 319   return type;
 320 }
 321
 322 /**
 323  * g_boxed_copy:
 324  * @boxed_type: The type of @src_boxed.
 325  * @src_boxed: (not nullable): The boxed structure to be copied.
 326  *
 327  * Provide a copy of a boxed structure @src_boxed which is of type @boxed_type.
 328  *
 329  * Returns: (transfer full) (not nullable): The newly created copy of the boxed
 330  *    structure.
 331  */
 332 gpointer
 333 g_boxed_copy (GType         boxed_type,
 334               gconstpointer src_boxed)
 335 {
 336   GTypeValueTable *value_table;
 337   gpointer dest_boxed;
 338
 339   g_return_val_if_fail (G_TYPE_IS_BOXED (boxed_type), NULL);
 340   g_return_val_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE, NULL);
 341   g_return_val_if_fail (src_boxed != NULL, NULL);
 342
 343   value_table = g_type_value_table_peek (boxed_type);
 344   if (!value_table)
 345     g_return_val_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type), NULL);
 346
 347   /* check if our proxying implementation is used, we can short-cut here */
 348   if (value_table->value_copy == boxed_proxy_value_copy)
 349     dest_boxed = _g_type_boxed_copy (boxed_type, (gpointer) src_boxed);
 350   else
 351     {
 352       GValue src_value, dest_value;
 353
 354       /* we heavily rely on third-party boxed type value vtable
 355        * implementations to follow normal boxed value storage
 356        * (data[0].v_pointer is the boxed struct, and
 357        * data[1].v_uint holds the G_VALUE_NOCOPY_CONTENTS flag,
 358        * rest zero).
 359        * but then, we can expect that since we laid out the
 360        * g_boxed_*() API.
 361        * data[1].v_uint&G_VALUE_NOCOPY_CONTENTS shouldn't be set
 362        * after a copy.
 363        */
 364       /* equiv. to g_value_set_static_boxed() */
 365       value_meminit (&src_value, boxed_type);
 366       src_value.data[0].v_pointer = (gpointer) src_boxed;
 367       src_value.data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 368
 369       /* call third-party code copy function, fingers-crossed */
 370       value_meminit (&dest_value, boxed_type);
 371       value_table->value_copy (&src_value, &dest_value);
 372
 373       /* double check and grouse if things went wrong */
 374       if (dest_value.data[1].v_ulong)
 375         g_warning ("the copy_value() implementation of type '%s' seems to make use of reserved GValue fields",
 376                    g_type_name (boxed_type));
 377
 378       dest_boxed = dest_value.data[0].v_pointer;
 379     }
 380
 381   return dest_boxed;
 382 }
 383
 384 /**
 385  * g_boxed_free:
 386  * @boxed_type: The type of @boxed.
 387  * @boxed: (not nullable): The boxed structure to be freed.
 388  *
 389  * Free the boxed structure @boxed which is of type @boxed_type.
 390  */
 391 void
 392 g_boxed_free (GType    boxed_type,
 393               gpointer boxed)
 394 {
 395   GTypeValueTable *value_table;
 396
 397   g_return_if_fail (G_TYPE_IS_BOXED (boxed_type));
 398   g_return_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE);
 399   g_return_if_fail (boxed != NULL);
 400
 401   value_table = g_type_value_table_peek (boxed_type);
 402   if (!value_table)
 403     g_return_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type));
 404
 405   /* check if our proxying implementation is used, we can short-cut here */
 406   if (value_table->value_free == boxed_proxy_value_free)
 407     _g_type_boxed_free (boxed_type, boxed);
 408   else
 409     {
 410       GValue value;
 411
 412       /* see g_boxed_copy() on why we think we can do this */
 413       value_meminit (&value, boxed_type);
 414       value.data[0].v_pointer = boxed;
 415       value_table->value_free (&value);
 416     }
 417 }
 418
 419 /**
 420  * g_value_get_boxed:
 421  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 422  *
 423  * Get the contents of a %G_TYPE_BOXED derived #GValue.
 424  *
 425  * Returns: (transfer none): boxed contents of @value
 426  */
 427 gpointer
 428 g_value_get_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;
 434 }
 435
 436 /**
 437  * g_value_dup_boxed: (skip)
 438  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 439  *
 440  * Get the contents of a %G_TYPE_BOXED derived #GValue.  Upon getting,
 441  * the boxed value is duplicated and needs to be later freed with
 442  * g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (@value),
 443  * return_value);
 444  *
 445  * Returns: boxed contents of @value
 446  */
 447 gpointer
 448 g_value_dup_boxed (const GValue *value)
 449 {
 450   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 451   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 452
 453   return value->data[0].v_pointer ? g_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer) : NULL;
 454 }
 455
 456 static inline void
 457 value_set_boxed_internal (GValue       *value,
 458                           gconstpointer boxed,
 459                           gboolean      need_copy,
 460                           gboolean      need_free)
 461 {
 462   if (!boxed)
 463     {
 464       /* just resetting to NULL might not be desired, need to
 465        * have value reinitialized also (for values defaulting
 466        * to other default value states than a NULL data pointer),
 467        * g_value_reset() will handle this
 468        */
 469       g_value_reset (value);
 470       return;
 471     }
 472
 473   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 474     g_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 475   value->data[1].v_uint = need_free ? 0 : G_VALUE_NOCOPY_CONTENTS;
 476   value->data[0].v_pointer = need_copy ? g_boxed_copy (G_VALUE_TYPE (value), boxed) : (gpointer) boxed;
 477 }
 478
 479 /**
 480  * g_value_set_boxed:
 481  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 482  * @v_boxed: (nullable): boxed value to be set
 483  *
 484  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 485  */
 486 void
 487 g_value_set_boxed (GValue       *value,
 488                    gconstpointer boxed)
 489 {
 490   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 491   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 492
 493   value_set_boxed_internal (value, boxed, TRUE, TRUE);
 494 }
 495
 496 /**
 497  * g_value_set_static_boxed:
 498  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 499  * @v_boxed: (nullable): static boxed value to be set
 500  *
 501  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 502  * The boxed value is assumed to be static, and is thus not duplicated
 503  * when setting the #GValue.
 504  */
 505 void
 506 g_value_set_static_boxed (GValue       *value,
 507                           gconstpointer boxed)
 508 {
 509   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 510   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 511
 512   value_set_boxed_internal (value, boxed, FALSE, FALSE);
 513 }
 514
 515 /**
 516  * g_value_set_boxed_take_ownership:
 517  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 518  * @v_boxed: (nullable): duplicated unowned boxed value to be set
 519  *
 520  * This is an internal function introduced mainly for C marshallers.
 521  *
 522  * Deprecated: 2.4: Use g_value_take_boxed() instead.
 523  */
 524 void
 525 g_value_set_boxed_take_ownership (GValue       *value,
 526                                   gconstpointer boxed)
 527 {
 528   g_value_take_boxed (value, boxed);
 529 }
 530
 531 /**
 532  * g_value_take_boxed:
 533  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 534  * @v_boxed: (nullable): duplicated unowned boxed value to be set
 535  *
 536  * Sets the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed
 537  * and takes over the ownership of the callers reference to @v_boxed;
 538  * the caller doesn't have to unref it any more.
 539  *
 540  * Since: 2.4
 541  */
 542 void
 543 g_value_take_boxed (GValue       *value,
 544                     gconstpointer boxed)
 545 {
 546   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 547   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 548
 549   value_set_boxed_internal (value, boxed, FALSE, TRUE);
 550 }