gpointer
g_boxed_copy (GType boxed_type,
gconstpointer src_boxed)
{
GTypeValueTable *value_table;
gpointer dest_boxed;
g_return_val_if_fail (G_TYPE_IS_BOXED (boxed_type), NULL);
g_return_val_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE, NULL);
g_return_val_if_fail (src_boxed != NULL, NULL);
value_table = g_type_value_table_peek (boxed_type);
if (!value_table)
g_return_val_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type), NULL);
/* check if our proxying implementation is used, we can short-cut here */
if (value_table->value_copy == boxed_proxy_value_copy)
{
BoxedNode key, *node;
key.type = boxed_type;
node = g_bsearch_array_lookup (boxed_bsa, &boxed_bconfig, &key);
dest_boxed = node->copy ((gpointer) src_boxed);
}
else
{
GValue src_value, dest_value;
/* we heavil rely on third-party boxed type value vtable
* implementations to follow normal boxed value storage
* (data[0].v_pointer is the boxed struct, and
* data[1].v_uint holds the G_VALUE_NOCOPY_CONTENTS flag,
* rest zero).
* but then, we can expect that since we layed out the
* g_boxed_*() API.
* data[1].v_uint&G_VALUE_NOCOPY_CONTENTS shouldn't be set
* after a copy.
*/
/* equiv. to g_value_set_static_boxed() */
value_meminit (&src_value, boxed_type);
src_value.data[0].v_pointer = (gpointer) src_boxed;
src_value.data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
/* call third-party code copy fucntion, fingers-crossed */
value_meminit (&dest_value, boxed_type);
value_table->value_copy (&src_value, &dest_value);
/* double check and grouse if things went wrong */
if (dest_value.data[1].v_ulong ||
dest_value.data[2].v_ulong)
g_warning ("the copy_value() implementation of type `%s' seems to make use of reserved GValue fields",
g_type_name (boxed_type));
dest_boxed = dest_value.data[0].v_pointer;
}
return dest_boxed;
}
/**
* g_value_init_from_instance:
* @value: An uninitialized #GValue structure.
* @instance: (type GObject.TypeInstance): the instance
*
* Initializes and sets @value from an instantiatable type via the
* value_table's collect_value() function.
*
* Note: The @value will be initialised with the exact type of
* @instance. If you wish to set the @value's type to a different GType
* (such as a parent class GType), you need to manually call
* g_value_init() and g_value_set_instance().
*
* Since: 2.42
*/
void
g_value_init_from_instance (GValue *value,
gpointer instance)
{
g_return_if_fail (value != NULL && G_VALUE_TYPE(value) == 0);
if (G_IS_OBJECT (instance))
{
/* Fast-path.
* If G_IS_OBJECT() succeeds we know:
* * that instance is present and valid
* * that it is a GObject, and therefore we can directly
* use the collect implementation (g_object_ref) */
value_meminit (value, G_TYPE_FROM_INSTANCE (instance));
value->data[0].v_pointer = g_object_ref (instance);
}
else
{
GType g_type;
GTypeValueTable *value_table;
GTypeCValue cvalue;
gchar *error_msg;
g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
g_type = G_TYPE_FROM_INSTANCE (instance);
value_table = g_type_value_table_peek (g_type);
g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
memset (&cvalue, 0, sizeof (cvalue));
cvalue.v_pointer = instance;
/* setup and collect */
value_meminit (value, g_type);
value_table->value_init (value);
error_msg = value_table->collect_value (value, 1, &cvalue, 0);
if (error_msg)
{
g_warning ("%s: %s", G_STRLOC, error_msg);
g_free (error_msg);
/* we purposely leak the value here, it might not be
* in a sane state if an error condition occoured
*/
value_meminit (value, g_type);
value_table->value_init (value);
}
}
}
/**
* g_value_transform:
* @src_value: Source value.
* @dest_value: Target value.
*
* Tries to cast the contents of @src_value into a type appropriate
* to store in @dest_value, e.g. to transform a %G_TYPE_INT value
* into a %G_TYPE_FLOAT value. Performing transformations between
* value types might incur precision lossage. Especially
* transformations into strings might reveal seemingly arbitrary
* results and shouldn't be relied upon for production code (such
* as rcfile value or object property serialization).
*
* Returns: Whether a transformation rule was found and could be applied.
* Upon failing transformations, @dest_value is left untouched.
*/
gboolean
g_value_transform (const GValue *src_value,
GValue *dest_value)
{
GType dest_type;
g_return_val_if_fail (G_IS_VALUE (src_value), FALSE);
g_return_val_if_fail (G_IS_VALUE (dest_value), FALSE);
dest_type = G_VALUE_TYPE (dest_value);
if (g_value_type_compatible (G_VALUE_TYPE (src_value), dest_type))
{
g_value_copy (src_value, dest_value);
return TRUE;
}
else
{
GValueTransform transform = transform_func_lookup (G_VALUE_TYPE (src_value), dest_type);
if (transform)
{
g_value_unset (dest_value);
/* setup and transform */
value_meminit (dest_value, dest_type);
transform (src_value, dest_value);
return TRUE;
}
}
return FALSE;
}
/**
* g_value_init:
* @value: A zero-filled (uninitialized) #GValue structure.
* @g_type: Type the #GValue should hold values of.
*
* Initializes @value with the default value of @type.
*
* Returns: (transfer none): the #GValue structure that has been passed in
*/
GValue*
g_value_init (GValue *value,
GType g_type)
{
/* g_return_val_if_fail (G_TYPE_IS_VALUE (g_type), NULL); be more elaborate below */
g_return_val_if_fail (value != NULL, NULL);
/* g_return_val_if_fail (G_VALUE_TYPE (value) == 0, NULL); be more elaborate below */
if (G_TYPE_IS_VALUE (g_type) && G_VALUE_TYPE (value) == 0)
{
GTypeValueTable *value_table = g_type_value_table_peek (g_type);
/* setup and init */
value_meminit (value, g_type);
value_table->value_init (value);
}
else if (G_VALUE_TYPE (value))
g_warning ("%s: cannot initialize GValue with type '%s', the value has already been initialized as '%s'",
G_STRLOC,
g_type_name (g_type),
g_type_name (G_VALUE_TYPE (value)));
else /* !G_TYPE_IS_VALUE (g_type) */
g_warning ("%s: cannot initialize GValue with type '%s', %s",
G_STRLOC,
g_type_name (g_type),
g_type_value_table_peek (g_type) ?
"this type is abstract with regards to GValue use, use a more specific (derived) type" :
"this type has no GTypeValueTable implementation");
return value;
}
/**
* g_boxed_free:
* @boxed_type: The type of @boxed.
* @boxed: The boxed structure to be freed.
*
* Free the boxed structure @boxed which is of type @boxed_type.
*/
void
g_boxed_free (GType boxed_type,
gpointer boxed)
{
GTypeValueTable *value_table;
g_return_if_fail (G_TYPE_IS_BOXED (boxed_type));
g_return_if_fail (G_TYPE_IS_ABSTRACT (boxed_type) == FALSE);
g_return_if_fail (boxed != NULL);
value_table = g_type_value_table_peek (boxed_type);
if (!value_table)
g_return_if_fail (G_TYPE_IS_VALUE_TYPE (boxed_type));
/* check if our proxying implementation is used, we can short-cut here */
if (value_table->value_free == boxed_proxy_value_free)
{
BoxedNode key, *node;
key.type = boxed_type;
node = g_bsearch_array_lookup (boxed_bsa, &boxed_bconfig, &key);
node->free (boxed);
}
else
{
GValue value;
/* see g_boxed_copy() on why we think we can do this */
value_meminit (&value, boxed_type);
value.data[0].v_pointer = boxed;
value_table->value_free (&value);
}
}
/**
* g_value_set_instance:
* @value: An initialized #GValue structure.
* @instance: (allow-none): the instance
*
* Sets @value from an instantiatable type via the
* value_table's collect_value() function.
*/
void
g_value_set_instance (GValue *value,
gpointer instance)
{
GType g_type;
GTypeValueTable *value_table;
GTypeCValue cvalue;
gchar *error_msg;
g_return_if_fail (G_IS_VALUE (value));
if (instance)
{
g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
g_return_if_fail (g_value_type_compatible (G_TYPE_FROM_INSTANCE (instance), G_VALUE_TYPE (value)));
}
g_type = G_VALUE_TYPE (value);
value_table = g_type_value_table_peek (g_type);
g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
memset (&cvalue, 0, sizeof (cvalue));
cvalue.v_pointer = instance;
/* make sure value's value is free()d */
if (value_table->value_free)
value_table->value_free (value);
/* setup and collect */
value_meminit (value, g_type);
error_msg = value_table->collect_value (value, 1, &cvalue, 0);
if (error_msg)
{
g_warning ("%s: %s", G_STRLOC, error_msg);
g_free (error_msg);
/* we purposely leak the value here, it might not be
* in a sane state if an error condition occoured
*/
value_meminit (value, g_type);
value_table->value_init (value);
}
}
/**
* g_value_reset:
* @value: An initialized #GValue structure.
*
* Clears the current value in @value and resets it to the default value
* (as if the value had just been initialized).
*
* Returns: the #GValue structure that has been passed in
*/
GValue*
g_value_reset (GValue *value)
{
GTypeValueTable *value_table;
GType g_type;
g_return_val_if_fail (G_IS_VALUE (value), NULL);
g_type = G_VALUE_TYPE (value);
value_table = g_type_value_table_peek (g_type);
/* make sure value's value is free()d */
if (value_table->value_free)
value_table->value_free (value);
/* setup and init */
value_meminit (value, g_type);
value_table->value_init (value);
return value;
}
/**
* g_value_copy:
* @src_value: An initialized #GValue structure.
* @dest_value: An initialized #GValue structure of the same type as @src_value.
*
* Copies the value of @src_value into @dest_value.
*/
void
g_value_copy (const GValue *src_value,
GValue *dest_value)
{
g_return_if_fail (G_IS_VALUE (src_value));
g_return_if_fail (G_IS_VALUE (dest_value));
g_return_if_fail (g_value_type_compatible (G_VALUE_TYPE (src_value), G_VALUE_TYPE (dest_value)));
if (src_value != dest_value)
{
GType dest_type = G_VALUE_TYPE (dest_value);
GTypeValueTable *value_table = g_type_value_table_peek (dest_type);
/* make sure dest_value's value is free()d */
if (value_table->value_free)
value_table->value_free (dest_value);
/* setup and copy */
value_meminit (dest_value, dest_type);
value_table->value_copy (src_value, dest_value);
}
}
