Index

Package: Variant

Description

package Glib.Variant is

Glib.Variant.Gvariant is a variant datatype; it stores a value along with information about the type of that value. The range of possible values is determined by the type. The type system used by Glib.Variant.Gvariant is Glib.Variant.Gvariant_Type.

Glib.Variant.Gvariant instances always have a type and a value (which are given at construction time). The type and value of a Glib.Variant.Gvariant instance can never change other than by the Glib.Variant.Gvariant itself being destroyed. A Glib.Variant.Gvariant cannot contain a pointer.

Glib.Variant.Gvariant is reference counted using Glib.Variant.Ref and Glib.Variant.Unref. Glib.Variant.Gvariant also has floating reference counts -- see Glib.Variant.Ref_Sink.

Glib.Variant.Gvariant is completely threadsafe. A Glib.Variant.Gvariant instance can be concurrently accessed in any way from any number of threads without problems.

Glib.Variant.Gvariant is heavily optimised for dealing with data in serialised form. It works particularly well with data located in memory-mapped files. It can perform nearly all deserialisation operations in a small constant time, usually touching only a single memory page.

Serialised Glib.Variant.Gvariant data can also be sent over the network.

Glib.Variant.Gvariant is largely compatible with D-Bus. Almost all types of Glib.Variant.Gvariant instances can be sent over D-Bus. See Glib.Variant.Gvariant_Type for exceptions. (However, Glib.Variant.Gvariant's serialisation format is not the same as the serialisation format of a D-Bus message body: use Gdbus.Message.Gdbus_Message, in the gio library, for those.) For space-efficiency, the Glib.Variant.Gvariant serialisation format does not automatically include the variant's type or endianness, which must either be implied from context (such as knowledge that a particular file format always contains a little-endian G_VARIANT_TYPE_VARIANT) or supplied out-of-band (for instance, a type and/or endianness indicator could be placed at the beginning of a file, network message or network stream).

A Glib.Variant.Gvariant's size is limited mainly by any lower level operating system constraints, such as the number of bits in Gsize. For example, it is reasonable to have a 2GB file mapped into memory with Gmapped.File.Gmapped_File, and call g_variant_new_from_data on it.

For convenience to C programmers, Glib.Variant.Gvariant features powerful varargs-based value construction and destruction. This feature is designed to be embedded in other libraries.

There is a Python-inspired text language for describing Glib.Variant.Gvariant values. Glib.Variant.Gvariant includes a printer for this language and a parser with type inferencing. == Memory Use == Glib.Variant.Gvariant tries to be quite efficient with respect to memory use. This section gives a rough idea of how much memory is used by the current implementation. The information here is subject to change in the future.

The memory allocated by Glib.Variant.Gvariant can be grouped into 4 broad purposes: memory for serialised data, memory for the type information cache, buffer management memory and memory for the Glib.Variant.Gvariant structure itself. == Serialised Data Memory == This is the memory that is used for storing GVariant data in serialised form. This is what would be sent over the network or what would end up on disk.

The amount of memory required to store a boolean is 1 byte. 16, 32 and 64 bit integers and double precision floating point numbers use their "natural" size. Strings (including object path and signature strings) are stored with a nul terminator, and as such use the length of the string plus 1 byte.

Maybe types use no space at all to represent the null value and use the same amount of space (sometimes plus one byte) as the equivalent non-maybe-typed value to represent the non-null case.

Arrays use the amount of space required to store each of their members, concatenated. Additionally, if the items stored in an array are not of a fixed-size (ie: strings, other arrays, etc) then an additional framing offset is stored for each item. The size of this offset is either 1, 2 or 4 bytes depending on the overall size of the container. Additionally, extra padding bytes are added as required for alignment of child values.

Tuples (including dictionary entries) use the amount of space required to store each of their members, concatenated, plus one framing offset (as per arrays) for each non-fixed-sized item in the tuple, except for the last one. Additionally, extra padding bytes are added as required for alignment of child values.

Variants use the same amount of space as the item inside of the variant, plus 1 byte, plus the length of the type string for the item inside the variant.

As an example, consider a dictionary mapping strings to variants. In the case that the dictionary is empty, 0 bytes are required for the serialisation.

If we add an item "width" that maps to the int32 value of 500 then we will use 4 byte to store the int32 (so 6 for the variant containing it) and 6 bytes for the string. The variant must be aligned to 8 after the 6 bytes of the string, so that's 2 extra bytes. 6 (string) + 2 (padding) + 6 (variant) is 14 bytes used for the dictionary entry. An additional 1 byte is added to the array as a framing offset making a total of 15 bytes.

If we add another entry, "title" that maps to a nullable string that happens to have a value of null, then we use 0 bytes for the null value (and 3 bytes for the variant to contain it along with its type string) plus 6 bytes for the string. Again, we need 2 padding bytes. That makes a total of 6 + 2 + 3 = 11 bytes.

We now require extra padding between the two items in the array. After the 14 bytes of the first item, that's 2 bytes required. We now require 2 framing offsets for an extra two bytes. 14 + 2 + 11 + 2 = 29 bytes to encode the entire two-item dictionary. == Type Information Cache == For each GVariant type that currently exists in the program a type information structure is kept in the type information cache. The type information structure is required for rapid deserialisation.

Continuing with the above example, if a Glib.Variant.Gvariant exists with the type "a{sv}" then a type information struct will exist for "a{sv}", "{sv}", "s", and "v". Multiple uses of the same type will share the same type information. Additionally, all single-digit types are stored in read-only static memory and do not contribute to the writable memory footprint of a program using Glib.Variant.Gvariant.

Aside from the type information structures stored in read-only memory, there are two forms of type information. One is used for container types where there is a single element type: arrays and maybe types. The other is used for container types where there are multiple element types: tuples and dictionary entries.

Array type info structures are 6 * sizeof (void *), plus the memory required to store the type string itself. This means that on 32bit systems, the cache entry for "a{sv}" would require 30 bytes of memory (plus malloc overhead).

Tuple type info structures are 6 * sizeof (void *), plus 4 * sizeof (void *) for each item in the tuple, plus the memory required to store the type string itself. A 2-item tuple, for example, would have a type information structure that consumed writable memory in the size of 14 * sizeof (void *) (plus type string) This means that on 32bit systems, the cache entry for "{sv}" would require 61 bytes of memory (plus malloc overhead).

This means that in total, for our "a{sv}" example, 91 bytes of type information would be allocated.

The type information cache, additionally, uses a GHash_Table to store and lookup the cached items and stores a pointer to this hash table in static storage. The hash table is freed when there are zero items in the type cache.

Although these sizes may seem large it is important to remember that a program will probably only have a very small number of different types of values in it and that only one type information structure is required for many different values of the same type. == Buffer Management Memory == Glib.Variant.Gvariant uses an internal buffer management structure to deal with the various different possible sources of serialised data that it uses. The buffer is responsible for ensuring that the correct call is made when the data is no longer in use by Glib.Variant.Gvariant. This may involve a g_free or a g_slice_free or even g_mapped_file_unref.

One buffer management structure is used for each chunk of serialised data.

The size of the buffer management structure is 4 * (void *). On 32bit systems, that's 16 bytes. == GVariant structure == The size of a Glib.Variant.Gvariant structure is 6 * (void *). On 32 bit systems, that's 24 bytes.

Glib.Variant.Gvariant structures only exist if they are explicitly created with API calls. For example, if a Glib.Variant.Gvariant is constructed out of serialised data for the example given above (with the dictionary) then although there are 9 individual values that comprise the entire dictionary (two keys, two values, two variants containing the values, two dictionary entries, plus the dictionary itself), only 1 Glib.Variant.Gvariant instance exists -- the one referring to the dictionary.

If calls are made to start accessing the other values then Glib.Variant.Gvariant instances will exist for those values only for as long as they are in use (ie: until you call Glib.Variant.Unref). The type information is shared. The serialised data and the buffer management structure for that serialised data is shared by the child. == Summary == To put the entire example together, for our dictionary mapping strings to variants (with two entries, as given above), we are using 91 bytes of memory for type information, 29 byes of memory for the serialised data, 16 bytes for buffer management and 24 bytes for the Glib.Variant.Gvariant instance, or a total of 160 bytes, plus malloc overhead. If we were to use Glib.Variant.Get_Child_Value to access the two dictionary entries, we would use an additional 48 bytes. If we were to have other dictionaries of the same type, we would use more memory for the serialised data and buffer management for those dictionaries, but the type information would be shared.

Packages

GVariant_Class_Properties (new Glib.Generic_Properties.Generic_Internal_Discrete_Property)

package GVariant_Class_Properties is
      new Generic_Internal_Discrete_Property (GVariant_Class);

Classes

Gvariant

type Gvariant is new Glib.C_Boxed with null record;

Ancestors:

Primitive operations:

Check_Format_String
Dup_Bytestring_Array
From_Object_Free
G_New_Boolean
G_New_Bytestring
G_New_Bytestring_Array
G_New_Dict_Entry
G_New_Double
G_New_Handle
G_New_Object_Path
G_New_Signature
G_New_String
G_New_Uint16
G_New_Uint32
G_New_Uint64
G_New_Variant
Get_Bytestring_Array
Get_Child_Value
Get_Normal_Form
Get_Type_String
Gvariant_New_Boolean
Gvariant_New_Byte
Gvariant_New_Bytestring
Gvariant_New_Bytestring_Array
Gvariant_New_Dict_Entry
Gvariant_New_Double
Gvariant_New_Handle
Gvariant_New_Int16
Gvariant_New_Int32
Gvariant_New_Int64
Gvariant_New_Object_Path
Gvariant_New_Objv
Gvariant_New_Signature
Gvariant_New_String
Gvariant_New_Strv
Gvariant_New_Uint16
Gvariant_New_Uint32
Gvariant_New_Uint64
Gvariant_New_Variant
Is_Container
Is_Normal_Form
Lookup_Value
Print_String

Types

GVariant_Class

type GVariant_Class is (
      Class_Tuple,
      Class_Array,
      Class_Boolean,
      Class_Double,
      Class_Signature,
      Class_Handle,
      Class_Int32,
      Class_Maybe,
      Class_Int16,
      Class_Object_Path,
      Class_Uint16,
      Class_String,
      Class_Uint64,
      Class_Uint32,
      Class_Variant,
      Class_Int64,
      Class_Byte,
      Class_Dict_Entry);

Gvariant_Iter

type Gvariant_Iter is new Glib.C_Proxy;

Gvariant_Type

type Gvariant_Type is new Glib.C_Proxy;

Property_GVariant_Class

type Property_GVariant_Class is new GVariant_Class_Properties.Property;

Constants & Global variables

Subprograms & Entries

From_Object

function From_Object 
(Object: System.Address) return Gvariant;

From_Object_Free

function From_Object_Free 
(B: access Gvariant'Class) return Gvariant;

G_New_Boolean

procedure G_New_Boolean 
(Self: out Gvariant;
Value: Boolean);
Creates a new boolean Glib.Variant.Gvariant instance -- either True or False. Since: gtk+ 2.24 "value": a Boolean value

Gvariant_New_Boolean

function Gvariant_New_Boolean 
(Value: Boolean) return Gvariant;
Creates a new boolean Glib.Variant.Gvariant instance -- either True or False. Since: gtk+ 2.24 "value": a Boolean value

G_New_Byte

procedure G_New_Byte 
(Self: out Gvariant;
Value: Guchar);
Creates a new byte Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint8 value

Gvariant_New_Byte

function Gvariant_New_Byte 
(Value: Guchar) return Gvariant;
Creates a new byte Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint8 value

G_New_Bytestring

procedure G_New_Bytestring 
(Self: out Gvariant;
String: Gint_Array);
Creates an array-of-bytes Glib.Variant.Gvariant with the contents of String. This function is just like g_variant_new_string except that the string need not be valid utf8. The nul terminator character at the end of the string is stored in the array. Since: gtk+ 2.26 "string": a normal nul-terminated string in no particular encoding

Gvariant_New_Bytestring

function Gvariant_New_Bytestring 
(String: Gint_Array) return Gvariant;
Creates an array-of-bytes Glib.Variant.Gvariant with the contents of String. This function is just like g_variant_new_string except that the string need not be valid utf8. The nul terminator character at the end of the string is stored in the array. Since: gtk+ 2.26 "string": a normal nul-terminated string in no particular encoding

G_New_Bytestring_Array

procedure G_New_Bytestring_Array 
(Self: out Gvariant;
Strv: GNAT.Strings.String_List;
Length: Gssize);
Constructs an array of bytestring Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.26 "strv": an array of strings "length": the length of Strv, or -1

Gvariant_New_Bytestring_Array

function Gvariant_New_Bytestring_Array 
(Strv: GNAT.Strings.String_List;
Length: Gssize) return Gvariant;
Constructs an array of bytestring Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.26 "strv": an array of strings "length": the length of Strv, or -1

G_New_Dict_Entry

procedure G_New_Dict_Entry 
(Self: out Gvariant;
Key: Gvariant;
Value: Gvariant);
Creates a new dictionary entry Glib.Variant.Gvariant. Key and Value must be non-null. Key must be a value of a basic type (ie: not a container). If the Key or Value are floating references (see Glib.Variant.Ref_Sink), the new instance takes ownership of them as if via Glib.Variant.Ref_Sink. Since: gtk+ 2.24 "key": a basic Glib.Variant.Gvariant, the key "value": a Glib.Variant.Gvariant, the value

G_New_Dict_Entry

procedure G_New_Dict_Entry 
(Self: out Gvariant_Type;
Key: Gvariant_Type;
Value: Gvariant_Type);
Constructs the type corresponding to a dictionary entry with a key of type Key and a value of type Value. It is appropriate to call Glib.Variant.Free on the return value. "key": a basic Glib.Variant.Gvariant_Type "value": a Glib.Variant.Gvariant_Type

Gvariant_New_Dict_Entry

function Gvariant_New_Dict_Entry 
(Key: Gvariant;
Value: Gvariant) return Gvariant;
Creates a new dictionary entry Glib.Variant.Gvariant. Key and Value must be non-null. Key must be a value of a basic type (ie: not a container). If the Key or Value are floating references (see Glib.Variant.Ref_Sink), the new instance takes ownership of them as if via Glib.Variant.Ref_Sink. Since: gtk+ 2.24 "key": a basic Glib.Variant.Gvariant, the key "value": a Glib.Variant.Gvariant, the value

G_New_Double

procedure G_New_Double 
(Self: out Gvariant;
Value: Gdouble);
Creates a new double Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gdouble floating point value

Gvariant_New_Double

function Gvariant_New_Double 
(Value: Gdouble) return Gvariant;
Creates a new double Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gdouble floating point value

G_New_Handle

procedure G_New_Handle 
(Self: out Gvariant;
Value: Gint32);
Creates a new handle Glib.Variant.Gvariant instance. By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you're not interacting with D-Bus, you probably don't need them. Since: gtk+ 2.24 "value": a Gint32 value

Gvariant_New_Handle

function Gvariant_New_Handle 
(Value: Gint32) return Gvariant;
Creates a new handle Glib.Variant.Gvariant instance. By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you're not interacting with D-Bus, you probably don't need them. Since: gtk+ 2.24 "value": a Gint32 value

G_New_Int16

procedure G_New_Int16 
(Self: out Gvariant;
Value: Gint16);
Creates a new int16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gint16 value

Gvariant_New_Int16

function Gvariant_New_Int16 
(Value: Gint16) return Gvariant;
Creates a new int16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gint16 value

G_New_Int32

procedure G_New_Int32 
(Self: out Gvariant;
Value: Gint32);
Creates a new int32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gint32 value

Gvariant_New_Int32

function Gvariant_New_Int32 
(Value: Gint32) return Gvariant;
Creates a new int32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gint32 value

G_New_Int64

procedure G_New_Int64 
(Self: out Gvariant;
Value: Gint64);
Creates a new int64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gint64 value

Gvariant_New_Int64

function Gvariant_New_Int64 
(Value: Gint64) return Gvariant;
Creates a new int64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Gint64 value

G_New_Object_Path

procedure G_New_Object_Path 
(Self: out Gvariant;
Object_Path: UTF8_String);
Creates a D-Bus object path Glib.Variant.Gvariant with the contents of String. String must be a valid D-Bus object path. Use Glib.Variant.Is_Object_Path if you're not sure. Since: gtk+ 2.24 "object_path": a normal C nul-terminated string

Gvariant_New_Object_Path

function Gvariant_New_Object_Path 
(Object_Path: UTF8_String) return Gvariant;
Creates a D-Bus object path Glib.Variant.Gvariant with the contents of String. String must be a valid D-Bus object path. Use Glib.Variant.Is_Object_Path if you're not sure. Since: gtk+ 2.24 "object_path": a normal C nul-terminated string

G_New_Objv

procedure G_New_Objv 
(Self: out Gvariant;
Strv: GNAT.Strings.String_List;
Length: Gssize);
Constructs an array of object paths Glib.Variant.Gvariant from the given array of strings. Each string must be a valid Glib.Variant.Gvariant object path; see Glib.Variant.Is_Object_Path. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.30 "strv": an array of strings "length": the length of Strv, or -1

Gvariant_New_Objv

function Gvariant_New_Objv 
(Strv: GNAT.Strings.String_List;
Length: Gssize) return Gvariant;
Constructs an array of object paths Glib.Variant.Gvariant from the given array of strings. Each string must be a valid Glib.Variant.Gvariant object path; see Glib.Variant.Is_Object_Path. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.30 "strv": an array of strings "length": the length of Strv, or -1

G_New_Signature

procedure G_New_Signature 
(Self: out Gvariant;
Signature: UTF8_String);
Creates a D-Bus type signature Glib.Variant.Gvariant with the contents of String. String must be a valid D-Bus type signature. Use Glib.Variant.Is_Signature if you're not sure. Since: gtk+ 2.24 "signature": a normal C nul-terminated string

Gvariant_New_Signature

function Gvariant_New_Signature 
(Signature: UTF8_String) return Gvariant;
Creates a D-Bus type signature Glib.Variant.Gvariant with the contents of String. String must be a valid D-Bus type signature. Use Glib.Variant.Is_Signature if you're not sure. Since: gtk+ 2.24 "signature": a normal C nul-terminated string

G_New_String

procedure G_New_String 
(Self: out Gvariant;
String: UTF8_String);
Creates a string Glib.Variant.Gvariant with the contents of String. String must be valid utf8. Since: gtk+ 2.24 "string": a normal utf8 nul-terminated string

Gvariant_New_String

function Gvariant_New_String 
(String: UTF8_String) return Gvariant;
Creates a string Glib.Variant.Gvariant with the contents of String. String must be valid utf8. Since: gtk+ 2.24 "string": a normal utf8 nul-terminated string

G_New_Strv

procedure G_New_Strv 
(Self: out Gvariant;
Strv: GNAT.Strings.String_List;
Length: Gssize);
Constructs an array of strings Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.24 "strv": an array of strings "length": the length of Strv, or -1

Gvariant_New_Strv

function Gvariant_New_Strv 
(Strv: GNAT.Strings.String_List;
Length: Gssize) return Gvariant;
Constructs an array of strings Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.24 "strv": an array of strings "length": the length of Strv, or -1

G_New_Uint16

procedure G_New_Uint16 
(Self: out Gvariant;
Value: Guint16);
Creates a new uint16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint16 value

Gvariant_New_Uint16

function Gvariant_New_Uint16 
(Value: Guint16) return Gvariant;
Creates a new uint16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint16 value

G_New_Uint32

procedure G_New_Uint32 
(Self: out Gvariant;
Value: Guint32);
Creates a new uint32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint32 value

Gvariant_New_Uint32

function Gvariant_New_Uint32 
(Value: Guint32) return Gvariant;
Creates a new uint32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint32 value

G_New_Uint64

procedure G_New_Uint64 
(Self: out Gvariant;
Value: Guint64);
Creates a new uint64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint64 value

Gvariant_New_Uint64

function Gvariant_New_Uint64 
(Value: Guint64) return Gvariant;
Creates a new uint64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24 "value": a Guint64 value

G_New_Variant

procedure G_New_Variant 
(Self: out Gvariant;
Value: Gvariant);
Boxes Value. The result is a Glib.Variant.Gvariant instance representing a variant containing the original value. If Child is a floating reference (see Glib.Variant.Ref_Sink), the new instance takes ownership of Child. Since: gtk+ 2.24 "value": a Glib.Variant.Gvariant instance

Gvariant_New_Variant

function Gvariant_New_Variant 
(Value: Gvariant) return Gvariant;
Boxes Value. The result is a Glib.Variant.Gvariant instance representing a variant containing the original value. If Child is a floating reference (see Glib.Variant.Ref_Sink), the new instance takes ownership of Child. Since: gtk+ 2.24 "value": a Glib.Variant.Gvariant instance

G_New

procedure G_New 
(Self: out Gvariant_Type;
Type_String: UTF8_String);
Creates a new Glib.Variant.Gvariant_Type corresponding to the type string given by Type_String. It is appropriate to call Glib.Variant.Free on the return value. It is a programmer error to call this function with an invalid type string. Use Glib.Variant.String_Is_Valid if you are unsure. Since: gtk+ 2.24 "type_string": a valid GVariant type string

Gvariant_Type_New

function Gvariant_Type_New 
(Type_String: UTF8_String) return Gvariant_Type;
Creates a new Glib.Variant.Gvariant_Type corresponding to the type string given by Type_String. It is appropriate to call Glib.Variant.Free on the return value. It is a programmer error to call this function with an invalid type string. Use Glib.Variant.String_Is_Valid if you are unsure. Since: gtk+ 2.24 "type_string": a valid GVariant type string

Gvariant_Type_New_Dict_Entry

function Gvariant_Type_New_Dict_Entry 
(Key: Gvariant_Type;
Value: Gvariant_Type) return Gvariant_Type;
Constructs the type corresponding to a dictionary entry with a key of type Key and a value of type Value. It is appropriate to call Glib.Variant.Free on the return value. "key": a basic Glib.Variant.Gvariant_Type "value": a Glib.Variant.Gvariant_Type

Get_Type

function Get_Type return Glib.GType;

Byteswap

function Byteswap 
(Self: Gvariant) return Gvariant;
Performs a byteswapping operation on the contents of Value. The result is that all multi-byte numeric data contained in Value is byteswapped. That includes 16, 32, and 64bit signed and unsigned integers as well as file handles and double precision floating point values. This function is an identity mapping on any value that does not contain multi-byte numeric data. That include strings, booleans, bytes and containers containing only these things (recursively). The returned value is always in normal form and is marked as trusted. Since: gtk+ 2.24

Check_Format_String

function Check_Format_String 
(Self: Gvariant;
Format_String: UTF8_String;
Copy_Only: Boolean) return Boolean;
Checks if calling g_variant_get with Format_String on Value would be valid from a type-compatibility standpoint. Format_String is assumed to be a valid format string (from a syntactic standpoint). If Copy_Only is True then this function additionally checks that it would be safe to call Glib.Variant.Unref on Value immediately after the call to g_variant_get without invalidating the result. This is only possible if deep copies are made (ie: there are no pointers to the data inside of the soon-to-be-freed Glib.Variant.Gvariant instance). If this check fails then a g_critical is printed and False is returned. This function is meant to be used by functions that wish to provide varargs accessors to Glib.Variant.Gvariant values of uncertain values (eg: g_variant_lookup or g_menu_model_get_item_attribute). Since: gtk+ 2.34 "format_string": a valid Glib.Variant.Gvariant format string "copy_only": True to ensure the format string makes deep copies

Classify

function Classify 
(Self: Gvariant) return GVariant_Class;
Classifies Value according to its top-level type. Since: gtk+ 2.24

Dup_Bytestring_Array

function Dup_Bytestring_Array 
(Self: Gvariant;
Length: access Gsize) return GNAT.Strings.String_List;
Gets the contents of an array of array of bytes Glib.Variant.Gvariant. This call makes a deep copy; the return result should be released with g_strfreev. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.26 "length": the length of the result, or null

Dup_Objv

function Dup_Objv 
(Self: Gvariant;
Length: access Gsize) return GNAT.Strings.String_List;
Gets the contents of an array of object paths Glib.Variant.Gvariant. This call makes a deep copy; the return result should be released with g_strfreev. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.30 "length": the length of the result, or null

Dup_String

function Dup_String 
(Self: Gvariant;
Length: access Gsize) return UTF8_String;
Similar to Glib.Variant.Get_String except that instead of returning a constant string, the string is duplicated. The string will always be utf8 encoded. The return value must be freed using g_free. Since: gtk+ 2.24 "length": a pointer to a Gsize, to store the length

Dup_String

function Dup_String 
(Self: Gvariant_Type) return UTF8_String;
Returns a newly-allocated copy of the type string corresponding to Type. The returned string is nul-terminated. It is appropriate to call g_free on the return value.

Dup_Strv

function Dup_Strv 
(Self: Gvariant;
Length: access Gsize) return GNAT.Strings.String_List;
Gets the contents of an array of strings Glib.Variant.Gvariant. This call makes a deep copy; the return result should be released with g_strfreev. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.24 "length": the length of the result, or null

Get_Boolean

function Get_Boolean 
(Self: Gvariant) return Boolean;
Returns the boolean value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_BOOLEAN. Since: gtk+ 2.24

Get_Byte

function Get_Byte 
(Self: Gvariant) return Guchar;
Returns the byte value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_BYTE. Since: gtk+ 2.24

Get_Bytestring_Array

function Get_Bytestring_Array 
(Self: Gvariant;
Length: access Gsize) return GNAT.Strings.String_List;
Gets the contents of an array of array of bytes Glib.Variant.Gvariant. This call makes a shallow copy; the return result should be released with g_free, but the individual strings must not be modified. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.26 "length": the length of the result, or null

Get_Child_Value

function Get_Child_Value 
(Self: Gvariant;
Index: Gsize) return Gvariant;
Reads a child item out of a container Glib.Variant.Gvariant instance. This includes variants, maybes, arrays, tuples and dictionary entries. It is an error to call this function on any other type of Glib.Variant.Gvariant. It is an error if Index_ is greater than the number of child items in the container. See Glib.Variant.N_Children. The returned value is never floating. You should free it with Glib.Variant.Unref when you're done with it. This function is O(1). Since: gtk+ 2.24 "index_": the index of the child to fetch

Get_Double

function Get_Double 
(Self: Gvariant) return Gdouble;
Returns the double precision floating point value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_DOUBLE. Since: gtk+ 2.24

Get_Handle

function Get_Handle 
(Self: Gvariant) return Gint32;
Returns the 32-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_HANDLE. By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you're not interacting with D-Bus, you probably don't need them. Since: gtk+ 2.24

Get_Int16

function Get_Int16 
(Self: Gvariant) return Gint16;
Returns the 16-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_INT16. Since: gtk+ 2.24

Get_Int32

function Get_Int32 
(Self: Gvariant) return Gint32;
Returns the 32-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_INT32. Since: gtk+ 2.24

Get_Int64

function Get_Int64 
(Self: Gvariant) return Gint64;
Returns the 64-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_INT64. Since: gtk+ 2.24

Get_Maybe

function Get_Maybe 
(Self: Gvariant) return Gvariant;
Given a maybe-typed Glib.Variant.Gvariant instance, extract its value. If the value is Nothing, then this function returns null. Since: gtk+ 2.24

Get_Normal_Form

function Get_Normal_Form 
(Self: Gvariant) return Gvariant;
Gets a Glib.Variant.Gvariant instance that has the same value as Value and is trusted to be in normal form. If Value is already trusted to be in normal form then a new reference to Value is returned. If Value is not already trusted, then it is scanned to check if it is in normal form. If it is found to be in normal form then it is marked as trusted and a new reference to it is returned. If Value is found not to be in normal form then a new trusted Glib.Variant.Gvariant is created with the same value as Value. It makes sense to call this function if you've received Glib.Variant.Gvariant data from untrusted sources and you want to ensure your serialised output is definitely in normal form. Since: gtk+ 2.24

Get_Objv

function Get_Objv 
(Self: Gvariant;
Length: access Gsize) return GNAT.Strings.String_List;
Gets the contents of an array of object paths Glib.Variant.Gvariant. This call makes a shallow copy; the return result should be released with g_free, but the individual strings must not be modified. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.30 "length": the length of the result, or null

Get_Size

function Get_Size 
(Self: Gvariant) return Gsize;
Determines the number of bytes that would be required to store Value with Glib.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. Since: gtk+ 2.24

Get_String

function Get_String 
(Self: Gvariant;
Length: access Gsize) return UTF8_String;
Returns the string value of a Glib.Variant.Gvariant instance with a string type. This includes the types G_VARIANT_TYPE_STRING, G_VARIANT_TYPE_OBJECT_PATH and G_VARIANT_TYPE_SIGNATURE. The string will always be utf8 encoded. If Length is non-null then the length of the string (in bytes) is returned there. For trusted values, this information is already known. For untrusted values, a strlen will be performed. It is an error to call this function with a Value of any type other than those three. The return value remains valid as long as Value exists. Since: gtk+ 2.24 "length": a pointer to a Gsize, to store the length

Get_Strv

function Get_Strv 
(Self: Gvariant;
Length: access Gsize) return GNAT.Strings.String_List;
Gets the contents of an array of strings Glib.Variant.Gvariant. This call makes a shallow copy; the return result should be released with g_free, but the individual strings must not be modified. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.24 "length": the length of the result, or null

Get_Type

function Get_Type 
(Self: Gvariant) return Gvariant_Type;
Determines the type of Value. The return value is valid for the lifetime of Value and must not be freed. Since: gtk+ 2.24

Get_Type_String

function Get_Type_String 
(Self: Gvariant) return UTF8_String;
Returns the type string of Value. Unlike the result of calling Glib.Variant.Peek_String, this string is nul-terminated. This string belongs to Glib.Variant.Gvariant and must not be freed. Since: gtk+ 2.24

Get_Uint16

function Get_Uint16 
(Self: Gvariant) return Guint16;
Returns the 16-bit unsigned integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_UINT16. Since: gtk+ 2.24

Get_Uint32

function Get_Uint32 
(Self: Gvariant) return Guint32;
Returns the 32-bit unsigned integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_UINT32. Since: gtk+ 2.24

Get_Uint64

function Get_Uint64 
(Self: Gvariant) return Guint64;
Returns the 64-bit unsigned integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_UINT64. Since: gtk+ 2.24

Get_Variant

function Get_Variant 
(Self: Gvariant) return Gvariant;
Unboxes Value. The result is the Glib.Variant.Gvariant instance that was contained in Value. Since: gtk+ 2.24

Hash

function Hash 
(Self: Gvariant) return Guint;
Generates a hash value for a Glib.Variant.Gvariant instance. The output of this function is guaranteed to be the same for a given value only per-process. It may change between different processor architectures or even different versions of GLib. Do not use this function as a basis for building protocols or file formats. The type of Value is gconstpointer only to allow use of this function with GHash_Table. Value must be a Glib.Variant.Gvariant. Since: gtk+ 2.24

Is_Container

function Is_Container 
(Self: Gvariant) return Boolean;
Checks if Value is a container. Since: gtk+ 2.24

Is_Container

function Is_Container 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is a container type. Container types are any array, maybe, tuple, or dictionary entry types plus the variant type. This function returns True for any indefinite type for which every definite subtype is a container -- G_VARIANT_TYPE_ARRAY, for example.

Is_Floating

function Is_Floating 
(Self: Gvariant) return Boolean;
Checks whether Value has a floating reference count. This function should only ever be used to assert that a given variant is or is not floating, or for debug purposes. To acquire a reference to a variant that might be floating, always use Glib.Variant.Ref_Sink or Glib.Variant.Take_Ref. See Glib.Variant.Ref_Sink for more information about floating reference counts. Since: gtk+ 2.26

Is_Normal_Form

function Is_Normal_Form 
(Self: Gvariant) return Boolean;
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 Glib.Variant.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. Since: gtk+ 2.24

Is_Of_Type

function Is_Of_Type 
(Self: Gvariant;
The_Type: Gvariant_Type) return Boolean;
Checks if a value has a type matching the provided type. Since: gtk+ 2.24 "type": a Glib.Variant.Gvariant_Type

Iter_New

function Iter_New 
(Self: Gvariant) return Gvariant_Iter;
Creates a heap-allocated Glib.Variant.Gvariant_Iter for iterating over the items in Value. Use g_variant_iter_free to free the return value when you no longer need it. A reference is taken to Value and will be released only when g_variant_iter_free is called. Since: gtk+ 2.24

Lookup_Value

function Lookup_Value 
(Self: Gvariant;
Key: UTF8_String;
Expected_Type: Gvariant_Type) return Gvariant;
Looks up a value in a dictionary Glib.Variant.Gvariant. This function works with dictionaries of the type 'a{s*}' (and equally well with type 'a{o*}', but we only further discuss the string case for sake of clarity). In the event that Dictionary has the type 'a{sv}', the Expected_Type string specifies what type of value is expected to be inside of the variant. If the value inside the variant has a different type then null is returned. In the event that Dictionary has a value type other than 'v' then Expected_Type must directly match the key type and it is used to unpack the value directly or an error occurs. In either case, if Key is not found in Dictionary, null is returned. If the key is found and the value has the correct type, it is returned. If Expected_Type was specified then any non-null return value will have this type. Since: gtk+ 2.28 "key": the key to lookup in the dictionary "expected_type": a Glib.Variant.Gvariant_Type, or null

N_Children

function N_Children 
(Self: Gvariant) return Gsize;
Determines the number of children in a container Glib.Variant.Gvariant instance. This includes variants, maybes, arrays, tuples and dictionary entries. It is an error to call this function on any other type of Glib.Variant.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). Since: gtk+ 2.24

Print

function Print 
(Self: Gvariant;
Type_Annotate: Boolean) return UTF8_String;
Pretty-prints Value in the format understood by Glib.Variant.Parse. The format is described <link linkend='gvariant-text'>here</link>. If Type_Annotate is True, then type information is included in the output. Since: gtk+ 2.24 "type_annotate": True if type information should be included in the output

Print_String

function Print_String 
(Self: Gvariant;
String: Glib.String.Gstring;
Type_Annotate: Boolean) return Glib.String.Gstring;
Behaves as Glib.Variant.Print, but operates on a Glib.String.Gstring. If String is non-null then it is appended to and returned. Else, a new empty Glib.String.Gstring is allocated and it is returned. Since: gtk+ 2.24 "string": a Glib.String.Gstring, or null "type_annotate": True if type information should be included in the output

Ref

function Ref 
(Self: Gvariant) return Gvariant;
Increases the reference count of Value. Since: gtk+ 2.24

Ref_Sink

function Ref_Sink 
(Self: Gvariant) return Gvariant;
Glib.Variant.Gvariant uses a floating reference count system. All functions with names starting with 'g_variant_new_' return floating references. Calling Glib.Variant.Ref_Sink on a Glib.Variant.Gvariant with a floating reference will convert the floating reference into a full reference. Calling Glib.Variant.Ref_Sink on a non-floating Glib.Variant.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 Glib.Variant.Gvariant instance being inserted into a container will call Glib.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: gtk+ 2.24

Store

procedure Store 
(Self: Gvariant;
Data: System.Address);
Stores the serialised form of Value at Data. Data should be large enough. See Glib.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 Glib.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: gtk+ 2.24 "data": the location to store the serialised data at

Take_Ref

function Take_Ref 
(Self: Gvariant) return Gvariant;
If Value is floating, sink it. Otherwise, do nothing. Typically you want to use Glib.Variant.Ref_Sink in order to automatically do the correct thing with respect to floating or non-floating references, but there is one specific scenario where this function is helpful. The situation where this function is helpful is when creating an API that allows the user to provide a callback function that returns a Glib.Variant.Gvariant. We certainly want to allow the user the flexibility to return a non-floating reference from this callback (for the case where the value that is being returned already exists). At the same time, the style of the Glib.Variant.Gvariant API makes it likely that for newly-created Glib.Variant.Gvariant instances, the user can be saved some typing if they are allowed to return a Glib.Variant.Gvariant with a floating reference. Using this function on the return value of the user's callback allows the user to do whichever is more convenient for them. The caller will alway receives exactly one full reference to the value: either the one that was returned in the first place, or a floating reference that has been converted to a full reference. This function has an odd interaction when combined with Glib.Variant.Ref_Sink running at the same time in another thread on the same Glib.Variant.Gvariant instance. If Glib.Variant.Ref_Sink runs first then the result will be that the floating reference is converted to a hard reference. If Glib.Variant.Take_Ref runs first then the result will be that the floating reference is converted to a hard reference and an additional reference on top of that one is added. It is best to avoid this situation.

Unref

procedure Unref 
(Self: Gvariant);
Decreases the reference count of Value. When its reference count drops to 0, the memory used by the variant is freed. Since: gtk+ 2.24

Init

function Init 
(Self: Gvariant_Iter;
Value: Gvariant) return Gsize;
Initialises (without allocating) a Glib.Variant.Gvariant_Iter. Iter may be completely uninitialised prior to this call; its old value is ignored. The iterator remains valid for as long as Value exists, and need not be freed in any way. Since: gtk+ 2.24 "value": a container Glib.Variant.Gvariant

Next_Value

function Next_Value 
(Self: Gvariant_Iter) return Gvariant;
Gets the next item in the container. If no more items remain then null is returned. Use Glib.Variant.Unref to drop your reference on the return value when you no longer need it. == Iterating with Glib.Variant.Next_Value == /<!-- -->* recursively iterate a container *<!-- -->/ void iterate_container_recursive (GVariant *container) { GVariantIter iter; GVariant *child; g_variant_iter_init (&iter, container); while ((child = g_variant_iter_next_value (&iter))) { g_print ("type '%s'\n", g_variant_get_type_string (child)); if (g_variant_is_container (child)) iterate_container_recursive (child); g_variant_unref (child); } } Since: gtk+ 2.24

Element

function Element 
(Self: Gvariant_Type) return Gvariant_Type;

Get_String_Length

function Get_String_Length 
(Self: Gvariant_Type) return Gsize;

Is_Array

function Is_Array 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is an array type. This is true if the type string for Type starts with an 'a'. This function returns True for any indefinite type for which every definite subtype is an array type -- G_VARIANT_TYPE_ARRAY, for example.

Is_Basic

function Is_Basic 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is a basic type. Basic types are booleans, bytes, integers, doubles, strings, object paths and signatures. Only a basic type may be used as the key of a dictionary entry. This function returns False for all indefinite types except G_VARIANT_TYPE_BASIC.

Is_Definite

function Is_Definite 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is definite (ie: not indefinite). A type is definite if its type string does not contain any indefinite type characters ('*', '?', or 'r'). A Glib.Variant.Gvariant instance may not have an indefinite type, so calling this function on the result of Glib.Variant.Get_Type will always result in True being returned. Calling this function on an indefinite type like G_VARIANT_TYPE_ARRAY, however, will result in False being returned.

Is_Dict_Entry

function Is_Dict_Entry 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is a dictionary entry type. This is true if the type string for Type starts with a '{'. This function returns True for any indefinite type for which every definite subtype is a dictionary entry type -- G_VARIANT_TYPE_DICT_ENTRY, for example.

Is_Maybe

function Is_Maybe 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is a maybe type. This is true if the type string for Type starts with an 'm'. This function returns True for any indefinite type for which every definite subtype is a maybe type -- G_VARIANT_TYPE_MAYBE, for example.

Is_Subtype_Of

function Is_Subtype_Of 
(Self: Gvariant_Type;
Supertype: Gvariant_Type) return Boolean;
Checks if Type is a subtype of Supertype. This function returns True if Type is a subtype of Supertype. All types are considered to be subtypes of themselves. Aside from that, only indefinite types can have subtypes. "supertype": a Glib.Variant.Gvariant_Type

Is_Tuple

function Is_Tuple 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is a tuple type. This is true if the type string for Type starts with a '(' or if Type is G_VARIANT_TYPE_TUPLE. This function returns True for any indefinite type for which every definite subtype is a tuple type -- G_VARIANT_TYPE_TUPLE, for example.

Is_Variant

function Is_Variant 
(Self: Gvariant_Type) return Boolean;
Determines if the given Type is the variant type.

N_Items

function N_Items 
(Self: Gvariant_Type) return Gsize;

Peek_String

function Peek_String 
(Self: Gvariant_Type) return UTF8_String;
Returns the type string corresponding to the given Type. The result is not nul-terminated; in order to determine its length you must call Glib.Variant.Get_String_Length. To get a nul-terminated string, see Glib.Variant.Dup_String.

Is_Object_Path

function Is_Object_Path 
(String: UTF8_String) return Boolean;
Determines if a given string is a valid D-Bus object path. You should ensure that a string is a valid D-Bus object path before passing it to g_variant_new_object_path. A valid object path starts with '/' followed by zero or more sequences of characters separated by '/' characters. Each sequence must contain only the characters "[A-Z][a-z][0-9]_". No sequence (including the one following the final '/' character) may be empty. Since: gtk+ 2.24 "string": a normal C nul-terminated string

Is_Signature

function Is_Signature 
(String: UTF8_String) return Boolean;
Determines if a given string is a valid D-Bus type signature. You should ensure that a string is a valid D-Bus type signature before passing it to g_variant_new_signature. D-Bus type signatures consist of zero or more definite Glib.Variant.Gvariant_Type strings in sequence. Since: gtk+ 2.24 "string": a normal C nul-terminated string

Parse

function Parse 
(The_Type: Gvariant_Type;
Text: UTF8_String;
Limit: UTF8_String := "";
Endptr: GNAT.Strings.String_List) return Gvariant;
Parses a Glib.Variant.Gvariant from a text representation. A single Glib.Variant.Gvariant is parsed from the content of Text. The format is described <link linkend='gvariant-text'>here</link>. The memory at Limit will never be accessed and the parser behaves as if the character at Limit is the nul terminator. This has the effect of bounding Text. If Endptr is non-null then Text is permitted to contain data following the value that this function parses and Endptr will be updated to point to the first character past the end of the text parsed by this function. If Endptr is null and there is extra data then an error is returned. If Type is non-null then the value will be parsed to have that type. This may result in additional parse errors (in the case that the parsed value doesn't fit the type) but may also result in fewer errors (in the case that the type would have been ambiguous, such as with empty arrays). In the event that the parsing is successful, the resulting Glib.Variant.Gvariant is returned. In case of any error, null will be returned. If Error is non-null then it will be set to reflect the error that occurred. Officially, the language understood by the parser is "any string produced by Glib.Variant.Print". "type": a Glib.Variant.Gvariant_Type, or null "text": a string containing a GVariant in text form "limit": a pointer to the end of Text, or null "endptr": a location to store the end pointer, or null

Parser_Get_Error_Quark

function Parser_Get_Error_Quark return Glib.GQuark;

String_Is_Valid

function String_Is_Valid 
(Type_String: UTF8_String) return Boolean;
Checks if Type_String is a valid GVariant type string. This call is equivalent to calling g_variant_type_string_scan and confirming that the following character is a nul terminator. "type_string": a pointer to any string