/**
* g_variant_get_child_value:
* @value: a container #GVariant
* @index_: the index of the child to fetch
*
* Reads a child item out of a container #GVariant instance. This
* includes variants, maybes, arrays, tuples and dictionary
* entries. It is an error to call this function on any other type of
* #GVariant.
*
* It is an error if @index_ is greater than the number of child items
* in the container. See g_variant_n_children().
*
* The returned value is never floating. You should free it with
* g_variant_unref() when you're done with it.
*
* This function is O(1).
*
* Returns: (transfer full): the child at the specified index
*
* Since: 2.24
**/
GVariant *
g_variant_get_child_value (GVariant *value,
gsize index_)
{
g_return_val_if_fail (index_ < g_variant_n_children (value), NULL);
if (~g_atomic_int_get (&value->state) & STATE_SERIALISED)
{
g_variant_lock (value);
if (~value->state & STATE_SERIALISED)
{
GVariant *child;
child = g_variant_ref (value->contents.tree.children[index_]);
g_variant_unlock (value);
return child;
}
g_variant_unlock (value);
}
{
GVariantSerialised serialised = {
value->type_info,
(gpointer) value->contents.serialised.data,
value->size
};
GVariantSerialised s_child;
GVariant *child;
/* get the serialiser to extract the serialised data for the child
* from the serialised data for the container
*/
s_child = g_variant_serialised_get_child (serialised, index_);
/* create a new serialised instance out of it */
child = g_slice_new (GVariant);
#ifdef GSTREAMER_LITE
if (child == NULL) {
return NULL;
}
#endif // GSTREAMER_LITE
child->type_info = s_child.type_info;
child->state = (value->state & STATE_TRUSTED) |
STATE_SERIALISED;
child->size = s_child.size;
child->ref_count = 1;
child->contents.serialised.bytes =
g_bytes_ref (value->contents.serialised.bytes);
child->contents.serialised.data = s_child.data;
return child;
}
}
/**
* g_variant_is_normal_form:
* @value: a #GVariant instance
*
* Checks if @value is in normal form.
*
* The main reason to do this is to detect if a given chunk of
* serialised data is in normal form: load the data into a #GVariant
* using g_variant_new_from_data() and then use this function to
* check.
*
* If @value is found to be in normal form then it will be marked as
* being trusted. If the value was already marked as being trusted then
* this function will immediately return %TRUE.
*
* Returns: %TRUE if @value is in normal form
*
* Since: 2.24
**/
gboolean
g_variant_is_normal_form (GVariant *value)
{
if (value->state & STATE_TRUSTED)
return TRUE;
g_variant_lock (value);
if (value->state & STATE_SERIALISED)
{
GVariantSerialised serialised = {
value->type_info,
(gpointer) value->contents.serialised.data,
value->size
};
if (g_variant_serialised_is_normal (serialised))
value->state |= STATE_TRUSTED;
}
else
{
gboolean normal = TRUE;
gsize i;
for (i = 0; i < value->contents.tree.n_children; i++)
normal &= g_variant_is_normal_form (value->contents.tree.children[i]);
if (normal)
value->state |= STATE_TRUSTED;
}
g_variant_unlock (value);
return (value->state & STATE_TRUSTED) != 0;
}
/**
* g_variant_get_data:
* @value: a #GVariant instance
*
* Returns a pointer to the serialised form of a #GVariant instance.
* The returned data may not be in fully-normalised form if read from an
* untrusted source. The returned data must not be freed; it remains
* valid for as long as @value exists.
*
* If @value is a fixed-sized value that was deserialised from a
* corrupted serialised container then %NULL may be returned. In this
* case, the proper thing to do is typically to use the appropriate
* number of nul bytes in place of @value. If @value is not fixed-sized
* then %NULL is never returned.
*
* In the case that @value is already in serialised form, this function
* is O(1). If the value is not already in serialised form,
* serialisation occurs implicitly and is approximately O(n) in the size
* of the result.
*
* To deserialise the data returned by this function, in addition to the
* serialised data, you must know the type of the #GVariant, and (if the
* machine might be different) the endianness of the machine that stored
* it. As a result, file formats or network messages that incorporate
* serialised #GVariants must include this information either
* implicitly (for instance "the file always contains a
* %G_VARIANT_TYPE_VARIANT and it is always in little-endian order") or
* explicitly (by storing the type and/or endianness in addition to the
* serialised data).
*
* Returns: (transfer none): the serialised form of @value, or %NULL
*
* Since: 2.24
**/
gconstpointer
g_variant_get_data (GVariant *value)
{
g_variant_lock (value);
g_variant_ensure_serialised (value);
g_variant_unlock (value);
return value->contents.serialised.data;
}
/**
* g_variant_get_size:
* @value: a #GVariant instance
*
* Determines the number of bytes that would be required to store @value
* with g_variant_store().
*
* If @value has a fixed-sized type then this function always returned
* that fixed size.
*
* In the case that @value is already in serialised form or the size has
* already been calculated (ie: this function has been called before)
* then this function is O(1). Otherwise, the size is calculated, an
* operation which is approximately O(n) in the number of values
* involved.
*
* Returns: the serialised size of @value
*
* Since: 2.24
**/
gsize
g_variant_get_size (GVariant *value)
{
g_variant_lock (value);
g_variant_ensure_size (value);
g_variant_unlock (value);
return value->size;
}
/**
* g_variant_get_data_as_bytes:
* @value: a #GVariant
*
* Returns a pointer to the serialised form of a #GVariant instance.
* The semantics of this function are exactly the same as
* g_variant_get_data(), except that the returned #GBytes holds
* a reference to the variant data.
*
* Returns: (transfer full): A new #GBytes representing the variant data
*
* Since: 2.36
*/
GBytes *
g_variant_get_data_as_bytes (GVariant *value)
{
g_variant_lock (value);
g_variant_ensure_serialised (value);
g_variant_unlock (value);
return g_bytes_ref (value->contents.serialised.bytes);
}
/**
* g_variant_ref_sink:
* @value: a #GVariant
* @returns: the same @value
*
* #GVariant uses a floating reference count system. All functions with
* names starting with <literal>g_variant_new_</literal> return floating
* references.
*
* Calling g_variant_ref_sink() on a #GVariant with a floating reference
* will convert the floating reference into a full reference. Calling
* g_variant_ref_sink() on a non-floating #GVariant results in an
* additional normal reference being added.
*
* In other words, if the @value is floating, then this call "assumes
* ownership" of the floating reference, converting it to a normal
* reference. If the @value is not floating, then this call adds a
* new normal reference increasing the reference count by one.
*
* All calls that result in a #GVariant instance being inserted into a
* container will call g_variant_ref_sink() on the instance. This means
* that if the value was just created (and has only its floating
* reference) then the container will assume sole ownership of the value
* at that point and the caller will not need to unreference it. This
* makes certain common styles of programming much easier while still
* maintaining normal refcounting semantics in situations where values
* are not floating.
*
* Since: 2.24
**/
GVariant *
g_variant_ref_sink (GVariant *value)
{
g_variant_lock (value);
if (~value->state & STATE_FLOATING)
g_variant_ref (value);
else
value->state &= ~STATE_FLOATING;
g_variant_unlock (value);
return value;
}
/**
* g_variant_ref_sink:
* @value: a #GVariant
*
* #GVariant uses a floating reference count system. All functions with
* names starting with `g_variant_new_` return floating
* references.
*
* Calling g_variant_ref_sink() on a #GVariant with a floating reference
* will convert the floating reference into a full reference. Calling
* g_variant_ref_sink() on a non-floating #GVariant results in an
* additional normal reference being added.
*
* In other words, if the @value is floating, then this call "assumes
* ownership" of the floating reference, converting it to a normal
* reference. If the @value is not floating, then this call adds a
* new normal reference increasing the reference count by one.
*
* All calls that result in a #GVariant instance being inserted into a
* container will call g_variant_ref_sink() on the instance. This means
* that if the value was just created (and has only its floating
* reference) then the container will assume sole ownership of the value
* at that point and the caller will not need to unreference it. This
* makes certain common styles of programming much easier while still
* maintaining normal refcounting semantics in situations where values
* are not floating.
*
* Returns: the same @value
*
* Since: 2.24
**/
GVariant *
g_variant_ref_sink (GVariant *value)
{
g_return_val_if_fail (value != NULL, NULL);
g_return_val_if_fail (value->ref_count > 0, NULL);
g_variant_lock (value);
if (~value->state & STATE_FLOATING)
g_variant_ref (value);
else
value->state &= ~STATE_FLOATING;
g_variant_unlock (value);
return value;
}
/**
* g_variant_store:
* @value: the #GVariant to store
* @data: the location to store the serialised data at
*
* Stores the serialised form of @value at @data. @data should be
* large enough. See g_variant_get_size().
*
* The stored data is in machine native byte order but may not be in
* fully-normalised form if read from an untrusted source. See
* g_variant_get_normal_form() for a solution.
*
* As with g_variant_get_data(), to be able to deserialise the
* serialised variant successfully, its type and (if the destination
* machine might be different) its endianness must also be available.
*
* This function is approximately O(n) in the size of @data.
*
* Since: 2.24
**/
void
g_variant_store (GVariant *value,
gpointer data)
{
g_variant_lock (value);
if (value->state & STATE_SERIALISED)
{
if (value->contents.serialised.data != NULL)
memcpy (data, value->contents.serialised.data, value->size);
else
memset (data, 0, value->size);
}
else
g_variant_serialise (value, data);
g_variant_unlock (value);
}
/**
* g_variant_get_data_as_bytes:
* @value: a #GVariant
*
* Returns a pointer to the serialised form of a #GVariant instance.
* The semantics of this function are exactly the same as
* g_variant_get_data(), except that the returned #GBytes holds
* a reference to the variant data.
*
* Returns: (transfer full): A new #GBytes representing the variant data
*
* Since: 2.36
*/
GBytes *
g_variant_get_data_as_bytes (GVariant *value)
{
const gchar *bytes_data;
const gchar *data;
gsize bytes_size;
gsize size;
g_variant_lock (value);
g_variant_ensure_serialised (value);
g_variant_unlock (value);
bytes_data = g_bytes_get_data (value->contents.serialised.bytes, &bytes_size);
data = value->contents.serialised.data;
size = value->size;
if (data == bytes_data && size == bytes_size)
return g_bytes_ref (value->contents.serialised.bytes);
else
return g_bytes_new_from_bytes (value->contents.serialised.bytes,
data - bytes_data, size);
}
/**
* g_variant_n_children:
* @value: a container #GVariant
*
* Determines the number of children in a container #GVariant instance.
* This includes variants, maybes, arrays, tuples and dictionary
* entries. It is an error to call this function on any other type of
* #GVariant.
*
* For variants, the return value is always 1. For values with maybe
* types, it is always zero or one. For arrays, it is the length of the
* array. For tuples it is the number of tuple items (which depends
* only on the type). For dictionary entries, it is always 2
*
* This function is O(1).
*
* Returns: the number of children in the container
*
* Since: 2.24
**/
gsize
g_variant_n_children (GVariant *value)
{
gsize n_children;
g_variant_lock (value);
if (value->state & STATE_SERIALISED)
{
GVariantSerialised serialised = {
value->type_info,
(gpointer) value->contents.serialised.data,
value->size
};
n_children = g_variant_serialised_n_children (serialised);
}
else
n_children = value->contents.tree.n_children;
g_variant_unlock (value);
return n_children;
}
/* < private >
* g_variant_fill_gvs:
* @serialised: a pointer to a #GVariantSerialised
* @data: a #GVariant instance
*
* This is the callback that is passed by a tree-form container instance
* to the serialiser. This callback gets called on each child of the
* container. Each child is responsible for performing the following
* actions:
*
* - reporting its type
*
* - reporting its serialised size (requires knowing the size first)
*
* - possibly storing its serialised form into the provided buffer
*/
static void
g_variant_fill_gvs (GVariantSerialised *serialised,
gpointer data)
{
GVariant *value = data;
g_variant_lock (value);
g_variant_ensure_size (value);
g_variant_unlock (value);
if (serialised->type_info == NULL)
serialised->type_info = value->type_info;
g_assert (serialised->type_info == value->type_info);
if (serialised->size == 0)
serialised->size = value->size;
g_assert (serialised->size == value->size);
if (serialised->data)
/* g_variant_store() is a public API, so it
* it will reacquire the lock if it needs to.
*/
g_variant_store (value, serialised->data);
}
