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 /* This one can't use G_DEFINE_BOXED_TYPE (GStrv, g_strv, g_strdupv, g_strfreev) */
 169 GType
 170 g_strv_get_type (void)
 171 {
 172   static volatile gsize g_define_type_id__volatile = 0;
 173
 174   if (g_once_init_enter (&g_define_type_id__volatile))
 175     {
 176       GType g_define_type_id =
 177         g_boxed_type_register_static (g_intern_static_string ("GStrv"),
 178                                       (GBoxedCopyFunc) g_strdupv,
 179                                       (GBoxedFreeFunc) g_strfreev);
 180
 181       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
 182     }
 183
 184   return g_define_type_id__volatile;
 185 }
 186
 187 /**
 188  * g_variant_get_gtype:
 189  *
 190  * Since: 2.24
 191  * Deprecated: 2.26
 192  */
 193 GType
 194 g_variant_get_gtype (void)
 195 {
 196   return G_TYPE_VARIANT;
 197 }
 198
 199 static void
 200 boxed_proxy_value_init (GValue *value)
 201 {
 202   value->data[0].v_pointer = NULL;
 203 }
 204
 205 static void
 206 boxed_proxy_value_free (GValue *value)
 207 {
 208   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 209     _g_type_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 210 }
 211
 212 static void
 213 boxed_proxy_value_copy (const GValue *src_value,
 214                         GValue       *dest_value)
 215 {
 216   if (src_value->data[0].v_pointer)
 217     dest_value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (src_value), src_value->data[0].v_pointer);
 218   else
 219     dest_value->data[0].v_pointer = src_value->data[0].v_pointer;
 220 }
 221
 222 static gpointer
 223 boxed_proxy_value_peek_pointer (const GValue *value)
 224 {
 225   return value->data[0].v_pointer;
 226 }
 227
 228 static gchar*
 229 boxed_proxy_collect_value (GValue      *value,
 230                            guint        n_collect_values,
 231                            GTypeCValue *collect_values,
 232                            guint        collect_flags)
 233 {
 234   if (!collect_values[0].v_pointer)
 235     value->data[0].v_pointer = NULL;
 236   else
 237     {
 238       if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 239         {
 240           value->data[0].v_pointer = collect_values[0].v_pointer;
 241           value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 242         }
 243       else
 244         value->data[0].v_pointer = _g_type_boxed_copy (G_VALUE_TYPE (value), collect_values[0].v_pointer);
 245     }
 246
 247   return NULL;
 248 }
 249
 250 static gchar*
 251 boxed_proxy_lcopy_value (const GValue *value,
 252                          guint         n_collect_values,
 253                          GTypeCValue  *collect_values,
 254                          guint         collect_flags)
 255 {
 256   gpointer *boxed_p = collect_values[0].v_pointer;
 257
 258   if (!boxed_p)
 259     return g_strdup_printf ("value location for '%s' passed as NULL", G_VALUE_TYPE_NAME (value));
 260
 261   if (!value->data[0].v_pointer)
 262     *boxed_p = NULL;
 263   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 264     *boxed_p = value->data[0].v_pointer;
 265   else
 266     *boxed_p = _g_type_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer);
 267
 268   return NULL;
 269 }
 270
 271 /**
 272  * g_boxed_type_register_static:
 273  * @name: Name of the new boxed type.
 274  * @boxed_copy: Boxed structure copy function.
 275  * @boxed_free: Boxed structure free function.
 276  *
 277  * This function creates a new %G_TYPE_BOXED derived type id for a new
 278  * boxed type with name @name. Boxed type handling functions have to be
 279  * provided to copy and free opaque boxed structures of this type.
 280  *
 281  * Returns: New %G_TYPE_BOXED derived type id for @name.
 282  */
 283 GType
 284 g_boxed_type_register_static (const gchar   *name,
 285                               GBoxedCopyFunc boxed_copy,
 286                               GBoxedFreeFunc boxed_free)
 287 {
 288   static const GTypeValueTable vtable = {
 289     boxed_proxy_value_init,
 290     boxed_proxy_value_free,
 291     boxed_proxy_value_copy,
 292     boxed_proxy_value_peek_pointer,
 293     "p",
 294     boxed_proxy_collect_value,
 295     "p",
 296     boxed_proxy_lcopy_value,
 297   };
 298   GTypeInfo type_info = {
 299     0,                  /* class_size */
 300     NULL,               /* base_init */
 301     NULL,               /* base_finalize */
 302     NULL,               /* class_init */
 303     NULL,               /* class_finalize */
 304     NULL,               /* class_data */
 305     0,                  /* instance_size */
 306     0,                  /* n_preallocs */
 307     NULL,               /* instance_init */
 308     &vtable,            /* value_table */
 309   };
 310   GType type;
 311
 312   g_return_val_if_fail (name != NULL, 0);
 313   g_return_val_if_fail (boxed_copy != NULL, 0);
 314   g_return_val_if_fail (boxed_free != NULL, 0);
 315   g_return_val_if_fail (g_type_from_name (name) == 0, 0);
 316
 317   type = g_type_register_static (G_TYPE_BOXED, name, &type_info, 0);
 318
 319   /* install proxy functions upon successful registration */
 320   if (type)
 321     _g_type_boxed_init (type, boxed_copy, boxed_free);
 322
 323   return type;
 324 }
 325
 326 /**
 327  * g_boxed_copy:
 328  * @boxed_type: The type of @src_boxed.
 329  * @src_boxed: The boxed structure to be copied.
 330  *
 331  * Provide a copy of a boxed structure @src_boxed which is of type @boxed_type.
 332  *
 333  * Returns: (transfer full): The newly created copy of the boxed structure.
 334  */
 335 gpointer
 336 g_boxed_copy (GType         boxed_type,
 337               gconstpointer src_boxed)
 338 {
 339   GTypeValueTable *value_table;
 340   gpointer dest_boxed;
 341
 342   g_return_val_if_fail (G_TYPE_IS_BOXED (boxed_type), NULL);
 343   g_return_val_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE, NULL);
 344   g_return_val_if_fail (src_boxed != NULL, NULL);
 345
 346   value_table = g_type_value_table_peek (boxed_type);
 347   if (!value_table)
 348     g_return_val_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type), NULL);
 349
 350   /* check if our proxying implementation is used, we can short-cut here */
 351   if (value_table->value_copy == boxed_proxy_value_copy)
 352     dest_boxed = _g_type_boxed_copy (boxed_type, (gpointer) src_boxed);
 353   else
 354     {
 355       GValue src_value, dest_value;
 356
 357       /* we heavily rely on third-party boxed type value vtable
 358        * implementations to follow normal boxed value storage
 359        * (data[0].v_pointer is the boxed struct, and
 360        * data[1].v_uint holds the G_VALUE_NOCOPY_CONTENTS flag,
 361        * rest zero).
 362        * but then, we can expect that since we laid out the
 363        * g_boxed_*() API.
 364        * data[1].v_uint&G_VALUE_NOCOPY_CONTENTS shouldn't be set
 365        * after a copy.
 366        */
 367       /* equiv. to g_value_set_static_boxed() */
 368       value_meminit (&src_value, boxed_type);
 369       src_value.data[0].v_pointer = (gpointer) src_boxed;
 370       src_value.data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 371
 372       /* call third-party code copy function, fingers-crossed */
 373       value_meminit (&dest_value, boxed_type);
 374       value_table->value_copy (&src_value, &dest_value);
 375
 376       /* double check and grouse if things went wrong */
 377       if (dest_value.data[1].v_ulong)
 378         g_warning ("the copy_value() implementation of type '%s' seems to make use of reserved GValue fields",
 379                    g_type_name (boxed_type));
 380
 381       dest_boxed = dest_value.data[0].v_pointer;
 382     }
 383
 384   return dest_boxed;
 385 }
 386
 387 /**
 388  * g_boxed_free:
 389  * @boxed_type: The type of @boxed.
 390  * @boxed: The boxed structure to be freed.
 391  *
 392  * Free the boxed structure @boxed which is of type @boxed_type.
 393  */
 394 void
 395 g_boxed_free (GType    boxed_type,
 396               gpointer boxed)
 397 {
 398   GTypeValueTable *value_table;
 399
 400   g_return_if_fail (G_TYPE_IS_BOXED (boxed_type));
 401   g_return_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE);
 402   g_return_if_fail (boxed != NULL);
 403
 404   value_table = g_type_value_table_peek (boxed_type);
 405   if (!value_table)
 406     g_return_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type));
 407
 408   /* check if our proxying implementation is used, we can short-cut here */
 409   if (value_table->value_free == boxed_proxy_value_free)
 410     _g_type_boxed_free (boxed_type, boxed);
 411   else
 412     {
 413       GValue value;
 414
 415       /* see g_boxed_copy() on why we think we can do this */
 416       value_meminit (&value, boxed_type);
 417       value.data[0].v_pointer = boxed;
 418       value_table->value_free (&value);
 419     }
 420 }
 421
 422 /**
 423  * g_value_get_boxed:
 424  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 425  *
 426  * Get the contents of a %G_TYPE_BOXED derived #GValue.
 427  *
 428  * Returns: (transfer none): boxed contents of @value
 429  */
 430 gpointer
 431 g_value_get_boxed (const GValue *value)
 432 {
 433   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 434   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 435
 436   return value->data[0].v_pointer;
 437 }
 438
 439 /**
 440  * g_value_dup_boxed: (skip)
 441  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 442  *
 443  * Get the contents of a %G_TYPE_BOXED derived #GValue.  Upon getting,
 444  * the boxed value is duplicated and needs to be later freed with
 445  * g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (@value),
 446  * return_value);
 447  *
 448  * Returns: boxed contents of @value
 449  */
 450 gpointer
 451 g_value_dup_boxed (const GValue *value)
 452 {
 453   g_return_val_if_fail (G_VALUE_HOLDS_BOXED (value), NULL);
 454   g_return_val_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)), NULL);
 455
 456   return value->data[0].v_pointer ? g_boxed_copy (G_VALUE_TYPE (value), value->data[0].v_pointer) : NULL;
 457 }
 458
 459 static inline void
 460 value_set_boxed_internal (GValue       *value,
 461                           gconstpointer boxed,
 462                           gboolean      need_copy,
 463                           gboolean      need_free)
 464 {
 465   if (!boxed)
 466     {
 467       /* just resetting to NULL might not be desired, need to
 468        * have value reinitialized also (for values defaulting
 469        * to other default value states than a NULL data pointer),
 470        * g_value_reset() will handle this
 471        */
 472       g_value_reset (value);
 473       return;
 474     }
 475
 476   if (value->data[0].v_pointer && !(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 477     g_boxed_free (G_VALUE_TYPE (value), value->data[0].v_pointer);
 478   value->data[1].v_uint = need_free ? 0 : G_VALUE_NOCOPY_CONTENTS;
 479   value->data[0].v_pointer = need_copy ? g_boxed_copy (G_VALUE_TYPE (value), boxed) : (gpointer) boxed;
 480 }
 481
 482 /**
 483  * g_value_set_boxed:
 484  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 485  * @v_boxed: (allow-none): boxed value to be set
 486  *
 487  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 488  */
 489 void
 490 g_value_set_boxed (GValue       *value,
 491                    gconstpointer boxed)
 492 {
 493   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 494   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 495
 496   value_set_boxed_internal (value, boxed, TRUE, TRUE);
 497 }
 498
 499 /**
 500  * g_value_set_static_boxed:
 501  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 502  * @v_boxed: (allow-none): static boxed value to be set
 503  *
 504  * Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.
 505  * The boxed value is assumed to be static, and is thus not duplicated
 506  * when setting the #GValue.
 507  */
 508 void
 509 g_value_set_static_boxed (GValue       *value,
 510                           gconstpointer boxed)
 511 {
 512   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 513   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 514
 515   value_set_boxed_internal (value, boxed, FALSE, FALSE);
 516 }
 517
 518 /**
 519  * g_value_set_boxed_take_ownership:
 520  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 521  * @v_boxed: (allow-none): duplicated unowned boxed value to be set
 522  *
 523  * This is an internal function introduced mainly for C marshallers.
 524  *
 525  * Deprecated: 2.4: Use g_value_take_boxed() instead.
 526  */
 527 void
 528 g_value_set_boxed_take_ownership (GValue       *value,
 529                                   gconstpointer boxed)
 530 {
 531   g_value_take_boxed (value, boxed);
 532 }
 533
 534 /**
 535  * g_value_take_boxed:
 536  * @value: a valid #GValue of %G_TYPE_BOXED derived type
 537  * @v_boxed: (allow-none): duplicated unowned boxed value to be set
 538  *
 539  * Sets the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed
 540  * and takes over the ownership of the callers reference to @v_boxed;
 541  * the caller doesn't have to unref it any more.
 542  *
 543  * Since: 2.4
 544  */
 545 void
 546 g_value_take_boxed (GValue       *value,
 547                     gconstpointer boxed)
 548 {
 549   g_return_if_fail (G_VALUE_HOLDS_BOXED (value));
 550   g_return_if_fail (G_TYPE_IS_VALUE (G_VALUE_TYPE (value)));
 551
 552   value_set_boxed_internal (value, boxed, FALSE, TRUE);
 553 }