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 2.1 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 GString *
 113 gstring_copy (GString *src_gstring)
 114 {
 115   return g_string_new_len (src_gstring->str, src_gstring->len);
 116 }
 117
 118 static void
 119 gstring_free (GString *gstring)
 120 {
 121   g_string_free (gstring, TRUE);
 122 }
 123
 124 G_DEFINE_BOXED_TYPE (GClosure, g_closure, g_closure_ref, g_closure_unref)
 125 G_DEFINE_BOXED_TYPE (GValue, g_value, value_copy, value_free)
 126 G_DEFINE_BOXED_TYPE (GValueArray, g_value_array, g_value_array_copy, g_value_array_free)
 127 G_DEFINE_BOXED_TYPE (GDate, g_date, g_date_copy, g_date_free)
 128 /* the naming is a bit odd, but GString is obviously not G_TYPE_STRING */
 129 G_DEFINE_BOXED_TYPE (GString, g_gstring, gstring_copy, gstring_free)
 130 G_DEFINE_BOXED_TYPE (GHashTable, g_hash_table, g_hash_table_ref, g_hash_table_unref)
 131 G_DEFINE_BOXED_TYPE (GArray, g_array, g_array_ref, g_array_unref)
 132 G_DEFINE_BOXED_TYPE (GPtrArray, g_ptr_array,g_ptr_array_ref, g_ptr_array_unref)
 133 G_DEFINE_BOXED_TYPE (GByteArray, g_byte_array, g_byte_array_ref, g_byte_array_unref)
 134 G_DEFINE_BOXED_TYPE (GBytes, g_bytes, g_bytes_ref, g_bytes_unref)
 135
 136 G_DEFINE_BOXED_TYPE (GRegex, g_regex, g_regex_ref, g_regex_unref)
 137 G_DEFINE_BOXED_TYPE (GMatchInfo, g_match_info, g_match_info_ref, g_match_info_unref)
 138
 139 #define g_variant_type_get_type g_variant_type_get_gtype
 140 G_DEFINE_BOXED_TYPE (GVariantType, g_variant_type, g_variant_type_copy, g_variant_type_free)
 141 #undef g_variant_type_get_type
 142
 143 G_DEFINE_BOXED_TYPE (GVariantBuilder, g_variant_builder, g_variant_builder_ref, g_variant_builder_unref)
 144 G_DEFINE_BOXED_TYPE (GVariantDict, g_variant_dict, g_variant_dict_ref, g_variant_dict_unref)
 145
 146 G_DEFINE_BOXED_TYPE (GError, g_error, g_error_copy, g_error_free)
 147
 148 G_DEFINE_BOXED_TYPE (GDateTime, g_date_time, g_date_time_ref, g_date_time_unref)
 149 G_DEFINE_BOXED_TYPE (GTimeZone, g_time_zone, g_time_zone_ref, g_time_zone_unref)
 150 G_DEFINE_BOXED_TYPE (GKeyFile, g_key_file, g_key_file_ref, g_key_file_unref)
 151 G_DEFINE_BOXED_TYPE (GMappedFile, g_mapped_file, g_mapped_file_ref, g_mapped_file_unref)
 152
 153 G_DEFINE_BOXED_TYPE (GMainLoop, g_main_loop, g_main_loop_ref, g_main_loop_unref)
 154 G_DEFINE_BOXED_TYPE (GMainContext, g_main_context, g_main_context_ref, g_main_context_unref)
 155 G_DEFINE_BOXED_TYPE (GSource, g_source, g_source_ref, g_source_unref)
 156 G_DEFINE_BOXED_TYPE (GPollFD, g_pollfd, pollfd_copy, g_free)
 157 G_DEFINE_BOXED_TYPE (GMarkupParseContext, g_markup_parse_context, g_markup_parse_context_ref, g_markup_parse_context_unref)
 158
 159 G_DEFINE_BOXED_TYPE (GThread, g_thread, g_thread_ref, g_thread_unref)
 160 G_DEFINE_BOXED_TYPE (GChecksum, g_checksum, g_checksum_copy, g_checksum_free)
 161
 162 G_DEFINE_BOXED_TYPE (GOptionGroup, g_option_group, g_option_group_ref, g_option_group_unref)
 163
 164 /* This one can't use G_DEFINE_BOXED_TYPE (GStrv, g_strv, g_strdupv, g_strfreev) */
 165 GType
 166 g_strv_get_type (void)
 167 {
 168   static volatile gsize g_define_type_id__volatile = 0;
 169
 170   if (g_once_init_enter (&g_define_type_id__volatile))
 171     {
 172       GType g_define_type_id =
 173         g_boxed_type_register_static (g_intern_static_string ("GStrv"),
 174                                       (GBoxedCopyFunc) g_strdupv,
 175                                       (GBoxedFreeFunc) g_strfreev);
 176
 177       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
 178     }
 179
 180   return g_define_type_id__volatile;
 181 }
 182
 183 GType
 184 g_variant_get_gtype (void)
 185 {
 186   return G_TYPE_VARIANT;
 187 }
 188
 189 static void
 190 boxed_proxy_value_init (GValue *value)
 191 {
 192   value->data[0].v_pointer = NULL;
 193 }
 194
 195 static void
 196 boxed_proxy_value_free (GValue *value)
 197 {
 198   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 199     _g_type_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 200 }
 201
 202 static void
 203 boxed_proxy_value_copy (const GValue *src_value,
 204                         GValue       *dest_value)
 205 {
 206   if (src_value->data[0].v_pointer)
 207     dest_value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (src_value), src_value->data[0].v_pointer);
 208   else
 209     dest_value->data[0].v_pointer = src_value->data[0].v_pointer;
 210 }
 211
 212 static gpointer
 213 boxed_proxy_value_peek_pointer (const GValue *value)
 214 {
 215   return value->data[0].v_pointer;
 216 }
 217
 218 static gchar*
 219 boxed_proxy_collect_value (GValue      *value,
 220                            guint        n_collect_values,
 221                            GTypeCValue *collect_values,
 222                            guint        collect_flags)
 223 {
 224   if (!collect_values[0].v_pointer)
 225     value->data[0].v_pointer = NULL;
 226   else
 227     {
 228       if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 229         {
 230           value->data[0].v_pointer = collect_values[0].v_pointer;
 231           value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 232         }
 233       else
 234         value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (value), collect_values[0].v_pointer);
 235     }
 236
 237   return NULL;
 238 }
 239
 240 static gchar*
 241 boxed_proxy_lcopy_value (const GValue *value,
 242                          guint         n_collect_values,
 243                          GTypeCValue  *collect_values,
 244                          guint         collect_flags)
 245 {
 246   gpointer *boxed_p = collect_values[0].v_pointer;
 247
 248   if (!boxed_p)
 249     return g_strdup_printf ("value location for '%s' passed as NULL", G_VALUE_TYPE_NAME (value));
 250
 251   if (!value->data[0].v_pointer)
 252     *boxed_p = NULL;
 253   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 254     *boxed_p = value->data[0].v_pointer;
 255   else
 256     *boxed_p = _g_type_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer);
 257
 258   return NULL;
 259 }
 260
 261 /**
 262  * g_boxed_type_register_static:
 263  * @name: Name of the new boxed type.
 264  * @boxed_copy: Boxed structure copy function.
 265  * @boxed_free: Boxed structure free function.
 266  *
 267  * This function creates a new %G_TYPE_BOXED derived type id for a new
 268  * boxed type with name @name. Boxed type handling functions have to be
 269  * provided to copy and free opaque boxed structures of this type.
 270  *
 271  * Returns: New %G_TYPE_BOXED derived type id for @name.
 272  */
 273 GType
 274 g_boxed_type_register_static (const gchar   *name,
 275                               GBoxedCopyFunc boxed_copy,
 276                               GBoxedFreeFunc boxed_free)
 277 {
 278   static const GTypeValueTable vtable = {
 279     boxed_proxy_value_init,
 280     boxed_proxy_value_free,
 281     boxed_proxy_value_copy,
 282     boxed_proxy_value_peek_pointer,
 283     "p",
 284     boxed_proxy_collect_value,
 285     "p",
 286     boxed_proxy_lcopy_value,
 287   };
 288   GTypeInfo type_info = {
 289     0,                  /* class_size */
 290     NULL,               /* base_init */
 291     NULL,               /* base_finalize */
 292     NULL,               /* class_init */
 293     NULL,               /* class_finalize */
 294     NULL,               /* class_data */
 295     0,                  /* instance_size */
 296     0,                  /* n_preallocs */
 297     NULL,               /* instance_init */
 298     &vtable,            /* value_table */
 299   };
 300   GType type;
 301
 302   g_return_val_if_fail (name != NULL, 0);
 303   g_return_val_if_fail (boxed_copy != NULL, 0);
 304   g_return_val_if_fail (boxed_free != NULL, 0);
 305   g_return_val_if_fail (g_type_from_name (name) == 0, 0);
 306
 307   type = g_type_register_static (G_TYPE_BOXED, name, &type_info, 0);
 308
 309   /* install proxy functions upon successful registration */
 310   if (type)
 311     _g_type_boxed_init (type, boxed_copy, boxed_free);
 312
 313   return type;
 314 }
 315
 316 /**
 317  * g_boxed_copy:
 318  * @boxed_type: The type of @src_boxed.
 319  * @src_boxed: (not nullable): The boxed structure to be copied.
 320  *
 321  * Provide a copy of a boxed structure @src_boxed which is of type @boxed_type.
 322  *
 323  * Returns: (transfer full) (not nullable): The newly created copy of the boxed
 324  *    structure.
 325  */
 326 gpointer
 327 g_boxed_copy (GType         boxed_type,
 328               gconstpointer src_boxed)
 329 {
 330   GTypeValueTable *value_table;
 331   gpointer dest_boxed;
 332
 333   g_return_val_if_fail (G_TYPE_IS_BOXED (boxed_type), NULL);
 334   g_return_val_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE, NULL);
 335   g_return_val_if_fail (src_boxed != NULL, NULL);
 336
 337   value_table = g_type_value_table_peek (boxed_type);
 338   if (!value_table)
 339     g_return_val_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type), NULL);
 340
 341   /* check if our proxying implementation is used, we can short-cut here */
 342   if (value_table->value_copy == boxed_proxy_value_copy)
 343     dest_boxed = _g_type_boxed_copy (boxed_type, (gpointer) src_boxed);
 344   else
 345     {
 346       GValue src_value, dest_value;
 347
 348       /* we heavily rely on third-party boxed type value vtable
 349        * implementations to follow normal boxed value storage
 350        * (data[0].v_pointer is the boxed struct, and
 351        * data[1].v_uint holds the G_VALUE_NOCOPY_CONTENTS flag,
 352        * rest zero).
 353        * but then, we can expect that since we laid out the
 354        * g_boxed_*() API.
 355        * data[1].v_uint&G_VALUE_NOCOPY_CONTENTS shouldn't be set
 356        * after a copy.
 357        */
 358       /* equiv. to g_value_set_static_boxed() */
 359       value_meminit (&src_value, boxed_type);
 360       src_value.data[0].v_pointer = (gpointer) src_boxed;
 361       src_value.data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 362
 363       /* call third-party code copy function, fingers-crossed */
 364       value_meminit (&dest_value, boxed_type);
 365       value_table->value_copy (&src_value, &dest_value);
 366
 367       /* double check and grouse if things went wrong */
 368       if (dest_value.data[1].v_ulong)
 369         g_warning ("the copy_value() implementation of type '%s' seems to make use of reserved GValue fields",
 370                    g_type_name (boxed_type));
 371
 372       dest_boxed = dest_value.data[0].v_pointer;
 373     }
 374
 375   return dest_boxed;
 376 }
 377
 378 /**
 379  * g_boxed_free:
 380  * @boxed_type: The type of @boxed.
 381  * @boxed: (not nullable): The boxed structure to be freed.
 382  *
 383  * Free the boxed structure @boxed which is of type @boxed_type.
 384  */
 385 void
 386 g_boxed_free (GType    boxed_type,
 387               gpointer boxed)
 388 {
 389   GTypeValueTable *value_table;
 390
 391   g_return_if_fail (G_TYPE_IS_BOXED (boxed_type));
 392   g_return_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE);
 393   g_return_if_fail (boxed != NULL);
 394
 395   value_table = g_type_value_table_peek (boxed_type);
 396   if (!value_table)
 397     g_return_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type));
 398
 399   /* check if our proxying implementation is used, we can short-cut here */
 400   if (value_table->value_free == boxed_proxy_value_free)
 401     _g_type_boxed_free (boxed_type, boxed);
 402   else
 403     {
 404       GValue value;
 405
 406       /* see g_boxed_copy() on why we think we can do this */
 407       value_meminit (&value, boxed_type);
 408       value.data[0].v_pointer = boxed;
 409       value_table->value_free (&value);
 410     }
 411 }
 412
 413 /**
 414  * g_value_get_boxed:
 415  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 416  *
 417  * Get the contents of a %G_TYPE_BOXED derived #GValue.
 418  *
 419  * Returns: (transfer none): boxed contents of @value
 420  */
 421 gpointer
 422 g_value_get_boxed (const GValue *value)
 423 {
 424   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 425   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 426
 427   return value->data[0].v_pointer;
 428 }
 429
 430 /**
 431  * g_value_dup_boxed: (skip)
 432  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 433  *
 434  * Get the contents of a %G_TYPE_BOXED derived #GValue.  Upon getting,
 435  * the boxed value is duplicated and needs to be later freed with
 436  * g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (@value),
 437  * return_value);
 438  *
 439  * Returns: boxed contents of @value
 440  */
 441 gpointer
 442 g_value_dup_boxed (const GValue *value)
 443 {
 444   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 445   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 446
 447   return value->data[0].v_pointer ? g_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer) : NULL;
 448 }
 449
 450 static inline void
 451 value_set_boxed_internal (GValue       *value,
 452                           gconstpointer boxed,
 453                           gboolean      need_copy,
 454                           gboolean      need_free)
 455 {
 456   if (!boxed)
 457     {
 458       /* just resetting to NULL might not be desired, need to
 459        * have value reinitialized also (for values defaulting
 460        * to other default value states than a NULL data pointer),
 461        * g_value_reset() will handle this
 462        */
 463       g_value_reset (value);
 464       return;
 465     }
 466
 467   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 468     g_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 469   value->data[1].v_uint = need_free ? 0 : G_VALUE_NOCOPY_CONTENTS;
 470   value->data[0].v_pointer = need_copy ? g_boxed_copy (G_VALUE_TYPE (value), boxed) : (gpointer) boxed;
 471 }
 472
 473 /**
 474  * g_value_set_boxed:
 475  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 476  * @v_boxed: (nullable): boxed value to be set
 477  *
 478  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 479  */
 480 void
 481 g_value_set_boxed (GValue       *value,
 482                    gconstpointer boxed)
 483 {
 484   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 485   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 486
 487   value_set_boxed_internal (value, boxed, TRUE, TRUE);
 488 }
 489
 490 /**
 491  * g_value_set_static_boxed:
 492  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 493  * @v_boxed: (nullable): static boxed value to be set
 494  *
 495  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 496  * The boxed value is assumed to be static, and is thus not duplicated
 497  * when setting the #GValue.
 498  */
 499 void
 500 g_value_set_static_boxed (GValue       *value,
 501                           gconstpointer boxed)
 502 {
 503   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 504   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 505
 506   value_set_boxed_internal (value, boxed, FALSE, FALSE);
 507 }
 508
 509 /**
 510  * g_value_set_boxed_take_ownership:
 511  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 512  * @v_boxed: (nullable): duplicated unowned boxed value to be set
 513  *
 514  * This is an internal function introduced mainly for C marshallers.
 515  *
 516  * Deprecated: 2.4: Use g_value_take_boxed() instead.
 517  */
 518 void
 519 g_value_set_boxed_take_ownership (GValue       *value,
 520                                   gconstpointer boxed)
 521 {
 522   g_value_take_boxed (value, boxed);
 523 }
 524
 525 /**
 526  * g_value_take_boxed:
 527  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 528  * @v_boxed: (nullable): duplicated unowned boxed value to be set
 529  *
 530  * Sets the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed
 531  * and takes over the ownership of the callers reference to @v_boxed;
 532  * the caller doesn't have to unref it any more.
 533  *
 534  * Since: 2.4
 535  */
 536 void
 537 g_value_take_boxed (GValue       *value,
 538                     gconstpointer boxed)
 539 {
 540   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 541   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 542
 543   value_set_boxed_internal (value, boxed, FALSE, TRUE);
 544 }