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glib/glib/gvarianttype.c
Ryan Lortie 2e53e50244 glib/: fully remove galias hacks
2010-07-07 19:34:35 -04:00

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/*
* Copyright © 2007, 2008 Ryan Lortie
* Copyright © 2009, 2010 Codethink Limited
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the licence, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Ryan Lortie <desrt@desrt.ca>
*/
#include "config.h"
#include "gvarianttype.h"
#include <glib/gtestutils.h>
#include <glib/gstrfuncs.h>
#include <string.h>
/**
* SECTION: gvarianttype
* @title: GVariantType
* @short_description: introduction to the GVariant type system
* @see_also: #GVariantType, #GVariant
*
* This section introduces the GVariant type system. It is based, in
* large part, on the DBus type system, with two major changes and some minor
* lifting of restrictions. The <ulink
* url='http://dbus.freedesktop.org/doc/dbus-specification.html'>DBus
* specification</ulink>, therefore, provides a significant amount of
* information that is useful when working with GVariant.
*
* The first major change with respect to the DBus type system is the
* introduction of maybe (or "nullable") types. Any type in GVariant can be
* converted to a maybe type, in which case, "nothing" (or "null") becomes a
* valid value. Maybe types have been added by introducing the
* character "<literal>m</literal>" to type strings.
*
* The second major change is that the GVariant type system supports the
* concept of "indefinite types" -- types that are less specific than
* the normal types found in DBus. For example, it is possible to speak
* of "an array of any type" in GVariant, where the DBus type system
* would require you to speak of "an array of integers" or "an array of
* strings". Indefinite types have been added by introducing the
* characters "<literal>*</literal>", "<literal>?</literal>" and
* "<literal>r</literal>" to type strings.
*
* Finally, all arbitrary restrictions relating to the complexity of
* types are lifted along with the restriction that dictionary entries
* may only appear nested inside of arrays.
*
* Just as in DBus, GVariant types are described with strings ("type
* strings"). Subject to the differences mentioned above, these strings
* are of the same form as those found in DBus. Note, however: DBus
* always works in terms of messages and therefore individual type
* strings appear nowhere in its interface. Instead, "signatures"
* are a concatenation of the strings of the type of each argument in a
* message. GVariant deals with single values directly so GVariant type
* strings always describe the type of exactly one value. This means
* that a DBus signature string is generally not a valid GVariant type
* string -- except in the case that it is the signature of a message
* containing exactly one argument.
*
* An indefinite type is similar in spirit to what may be called an
* abstract type in other type systems. No value can exist that has an
* indefinite type as its type, but values can exist that have types
* that are subtypes of indefinite types. That is to say,
* g_variant_get_type() will never return an indefinite type, but
* calling g_variant_is_a() with an indefinite type may return %TRUE.
* For example, you can not have a value that represents "an array of no
* particular type", but you can have an "array of integers" which
* certainly matches the type of "an array of no particular type", since
* "array of integers" is a subtype of "array of no particular type".
*
* This is similar to how instances of abstract classes may not
* directly exist in other type systems, but instances of their
* non-abstract subtypes may. For example, in GTK, no object that has
* the type of #GtkBin can exist (since #GtkBin is an abstract class),
* but a #GtkWindow can certainly be instantiated, and you would say
* that the #GtkWindow is a #GtkBin (since #GtkWindow is a subclass of
* #GtkBin).
*
* A detailed description of GVariant type strings is given here:
*
* <refsect2 id='gvariant-typestrings'>
* <title>GVariant Type Strings</title>
* <para>
* A GVariant type string can be any of the following:
* </para>
* <itemizedlist>
* <listitem>
* <para>
* any basic type string (listed below)
* </para>
* </listitem>
* <listitem>
* <para>
* "<literal>v</literal>", "<literal>r</literal>" or
* "<literal>*</literal>"
* </para>
* </listitem>
* <listitem>
* <para>
* one of the characters '<literal>a</literal>' or
* '<literal>m</literal>', followed by another type string
* </para>
* </listitem>
* <listitem>
* <para>
* the character '<literal>(</literal>', followed by a concatenation
* of zero or more other type strings, followed by the character
* '<literal>)</literal>'
* </para>
* </listitem>
* <listitem>
* <para>
* the character '<literal>{</literal>', followed by a basic type
* string (see below), followed by another type string, followed by
* the character '<literal>}</literal>'
* </para>
* </listitem>
* </itemizedlist>
* <para>
* A basic type string describes a basic type (as per
* g_variant_type_is_basic()) and is always a single
* character in length. The valid basic type strings are
* "<literal>b</literal>", "<literal>y</literal>",
* "<literal>n</literal>", "<literal>q</literal>",
* "<literal>i</literal>", "<literal>u</literal>",
* "<literal>x</literal>", "<literal>t</literal>",
* "<literal>h</literal>", "<literal>d</literal>",
* "<literal>s</literal>", "<literal>o</literal>",
* "<literal>g</literal>" and "<literal>?</literal>".
* </para>
* <para>
* The above definition is recursive to arbitrary depth.
* "<literal>aaaaai</literal>" and "<literal>(ui(nq((y)))s)</literal>"
* are both valid type strings, as is
* "<literal>a(aa(ui)(qna{ya(yd)}))</literal>".
* </para>
* <para>
* The meaning of each of the characters is as follows:
* </para>
* <informaltable>
* <tgroup cols='2'>
* <tbody>
* <row>
* <entry>
* <para>
* <emphasis role='strong'>Character</emphasis>
* </para>
* </entry>
* <entry>
* <para>
* <emphasis role='strong'>Meaning</emphasis>
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>b</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_BOOLEAN; a boolean value.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>y</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_BYTE; a byte.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>n</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_INT16; a signed 16 bit
* integer.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>q</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_UINT16; an unsigned 16 bit
* integer.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>i</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_INT32; a signed 32 bit
* integer.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>u</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_UINT32; an unsigned 32 bit
* integer.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>x</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_INT64; a signed 64 bit
* integer.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>t</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_UINT64; an unsigned 64 bit
* integer.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>h</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_HANDLE; a signed 32 bit
* value that, by convention, is used as an index into an array
* of file descriptors that are sent alongside a DBus message.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>d</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_DOUBLE; a double precision
* floating point value.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>s</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_STRING; a string.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>o</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_OBJECT_PATH; a string in
* the form of a DBus object path.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>g</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_STRING; a string in the
* form of a DBus type signature.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>?</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_BASIC; an indefinite type
* that is a supertype of any of the basic types.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>v</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_VARIANT; a container type
* that contain any other type of value.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>a</literal>
* </para>
* </entry>
* <entry>
* <para>
* used as a prefix on another type string to mean an array of
* that type; the type string "<literal>ai</literal>", for
* example, is the type of an array of 32 bit signed integers.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>m</literal>
* </para>
* </entry>
* <entry>
* <para>
* used as a prefix on another type string to mean a "maybe", or
* "nullable", version of that type; the type string
* "<literal>ms</literal>", for example, is the type of a value
* that maybe contains a string, or maybe contains nothing.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>()</literal>
* </para>
* </entry>
* <entry>
* <para>
* used to enclose zero or more other concatenated type strings
* to create a tuple type; the type string
* "<literal>(is)</literal>", for example, is the type of a pair
* of an integer and a string.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>r</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_TUPLE; an indefinite type
* that is a supertype of any tuple type, regardless of the
* number of items.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>{}</literal>
* </para>
* </entry>
* <entry>
* <para>
* used to enclose a basic type string concatenated with another
* type string to create a dictionary entry type, which usually
* appears inside of an array to form a dictionary; the type
* string "<literal>a{sd}</literal>", for example, is the type of
* a dictionary that maps strings to double precision floating
* point values.
* </para>
* <para>
* The first type (the basic type) is the key type and the second
* type is the value type. The reason that the first type is
* restricted to being a basic type is so that it can easily be
* hashed.
* </para>
* </entry>
* </row>
* <row>
* <entry>
* <para>
* <literal>*</literal>
* </para>
* </entry>
* <entry>
* <para>
* the type string of %G_VARIANT_TYPE_ANY; the indefinite type
* that is a supertype of all types. Note that, as with all type
* strings, this character represents exactly one type. It
* cannot be used inside of tuples to mean "any number of items".
* </para>
* </entry>
* </row>
* </tbody>
* </tgroup>
* </informaltable>
* <para>
* Any type string of a container that contains an indefinite type is,
* itself, an indefinite type. For example, the type string
* "<literal>a*</literal>" (corresponding to %G_VARIANT_TYPE_ARRAY) is
* an indefinite type that is a supertype of every array type.
* "<literal>(*s)</literal>" is a supertype of all tuples that
* contain exactly two items where the second item is a string.
* </para>
* <para>
* "<literal>a{?*}</literal>" is an indefinite type that is a
* supertype of all arrays containing dictionary entries where the key
* is any basic type and the value is any type at all. This is, by
* definition, a dictionary, so this type string corresponds to
* %G_VARIANT_TYPE_DICTIONARY. Note that, due to the restriction that
* the key of a dictionary entry must be a basic type,
* "<literal>{**}</literal>" is not a valid type string.
* </para>
* </refsect2>
*/
static gboolean
g_variant_type_check (const GVariantType *type)
{
const gchar *type_string;
if (type == NULL)
return FALSE;
type_string = (const gchar *) type;
#ifndef G_DISABLE_CHECKS
return g_variant_type_string_scan (type_string, NULL, NULL);
#else
return TRUE;
#endif
}
/**
* g_variant_type_string_scan:
* @string: a pointer to any string
* @limit: the end of @string, or %NULL
* @endptr: location to store the end pointer, or %NULL
* @returns: %TRUE if a valid type string was found
*
* Scan for a single complete and valid GVariant type string in @string.
* The memory pointed to by @limit (or bytes beyond it) is never
* accessed.
*
* If a valid type string is found, @endptr is updated to point to the
* first character past the end of the string that was found and %TRUE
* is returned.
*
* If there is no valid type string starting at @string, or if the type
* string does not end before @limit then %FALSE is returned.
*
* For the simple case of checking if a string is a valid type string,
* see g_variant_type_string_is_valid().
*
* Since: 2.24
**/
gboolean
g_variant_type_string_scan (const gchar *string,
const gchar *limit,
const gchar **endptr)
{
g_return_val_if_fail (string != NULL, FALSE);
if (string == limit || *string == '\0')
return FALSE;
switch (*string++)
{
case '(':
while (string == limit || *string != ')')
if (!g_variant_type_string_scan (string, limit, &string))
return FALSE;
string++;
break;
case '{':
if (string == limit || *string == '\0' || /* { */
!strchr ("bynqihuxtdsog?", *string++) || /* key */
!g_variant_type_string_scan (string, limit, &string) || /* value */
string == limit || *string++ != '}') /* } */
return FALSE;
break;
case 'm': case 'a':
return g_variant_type_string_scan (string, limit, endptr);
case 'b': case 'y': case 'n': case 'q': case 'i': case 'u':
case 'x': case 't': case 'd': case 's': case 'o': case 'g':
case 'v': case 'r': case '*': case '?': case 'h':
break;
default:
return FALSE;
}
if (endptr != NULL)
*endptr = string;
return TRUE;
}
/**
* g_variant_type_string_is_valid:
* @type_string: a pointer to any string
* @returns: %TRUE if @type_string is exactly one valid type string
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_string_is_valid (const gchar *type_string)
{
const gchar *endptr;
g_return_val_if_fail (type_string != NULL, FALSE);
if (!g_variant_type_string_scan (type_string, NULL, &endptr))
return FALSE;
return *endptr == '\0';
}
/**
* g_variant_type_free:
* @type: a #GVariantType, or %NULL
*
* Frees a #GVariantType that was allocated with
* g_variant_type_copy(), g_variant_type_new() or one of the container
* type constructor functions.
*
* In the case that @type is %NULL, this function does nothing.
*
* Since 2.24
**/
void
g_variant_type_free (GVariantType *type)
{
g_return_if_fail (type == NULL || g_variant_type_check (type));
g_free (type);
}
/**
* g_variant_type_copy:
* @type: a #GVariantType
* @returns: a new #GVariantType
*
* Makes a copy of a #GVariantType. It is appropriate to call
* g_variant_type_free() on the return value. @type may not be %NULL.
*
* Since 2.24
**/
GVariantType *
g_variant_type_copy (const GVariantType *type)
{
gsize length;
gchar *new;
g_return_val_if_fail (g_variant_type_check (type), NULL);
length = g_variant_type_get_string_length (type);
new = g_malloc (length + 1);
memcpy (new, type, length);
new[length] = '\0';
return (GVariantType *) new;
}
/**
* g_variant_type_new:
* @type_string: a valid GVariant type string
* @returns: a new #GVariantType
*
* Creates a new #GVariantType corresponding to the type string given
* by @type_string. It is appropriate to call g_variant_type_free() on
* the return value.
*
* It is a programmer error to call this function with an invalid type
* string. Use g_variant_type_string_is_valid() if you are unsure.
*
* Since: 2.24
*/
GVariantType *
g_variant_type_new (const gchar *type_string)
{
g_return_val_if_fail (type_string != NULL, NULL);
return g_variant_type_copy (G_VARIANT_TYPE (type_string));
}
/**
* g_variant_type_get_string_length:
* @type: a #GVariantType
* @returns: the length of the corresponding type string
*
* Returns the length of the type string corresponding to the given
* @type. This function must be used to determine the valid extent of
* the memory region returned by g_variant_type_peek_string().
*
* Since 2.24
**/
gsize
g_variant_type_get_string_length (const GVariantType *type)
{
const gchar *type_string = (const gchar *) type;
gint brackets = 0;
gsize index = 0;
g_return_val_if_fail (g_variant_type_check (type), 0);
do
{
while (type_string[index] == 'a' || type_string[index] == 'm')
index++;
if (type_string[index] == '(' || type_string[index] == '{')
brackets++;
else if (type_string[index] == ')' || type_string[index] == '}')
brackets--;
index++;
}
while (brackets);
return index;
}
/**
* g_variant_type_peek_string:
* @type: a #GVariantType
* @returns: the corresponding type string (not nul-terminated)
*
* Returns the type string corresponding to the given @type. The
* result is not nul-terminated; in order to determine its length you
* must call g_variant_type_get_string_length().
*
* To get a nul-terminated string, see g_variant_type_dup_string().
*
* Since 2.24
**/
const gchar *
g_variant_type_peek_string (const GVariantType *type)
{
g_return_val_if_fail (g_variant_type_check (type), NULL);
return (const gchar *) type;
}
/**
* g_variant_type_dup_string:
* @type: a #GVariantType
* @returns: the corresponding type 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.
*
* Since 2.24
**/
gchar *
g_variant_type_dup_string (const GVariantType *type)
{
g_return_val_if_fail (g_variant_type_check (type), NULL);
return g_strndup (g_variant_type_peek_string (type),
g_variant_type_get_string_length (type));
}
/**
* g_variant_type_is_definite:
* @type: a #GVariantType
* @returns: %TRUE if @type is definite
*
* 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 #GVariant instance may not have an indefinite type, so calling
* this function on the result of g_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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_definite (const GVariantType *type)
{
const gchar *type_string;
gsize type_length;
gsize i;
g_return_val_if_fail (g_variant_type_check (type), FALSE);
type_length = g_variant_type_get_string_length (type);
type_string = g_variant_type_peek_string (type);
for (i = 0; i < type_length; i++)
if (type_string[i] == '*' ||
type_string[i] == '?' ||
type_string[i] == 'r')
return FALSE;
return TRUE;
}
/**
* g_variant_type_is_container:
* @type: a #GVariantType
* @returns: %TRUE if @type is a container type
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_container (const GVariantType *type)
{
gchar first_char;
g_return_val_if_fail (g_variant_type_check (type), FALSE);
first_char = g_variant_type_peek_string (type)[0];
switch (first_char)
{
case 'a':
case 'm':
case 'r':
case '(':
case '{':
case 'v':
return TRUE;
default:
return FALSE;
}
}
/**
* g_variant_type_is_basic:
* @type: a #GVariantType
* @returns: %TRUE if @type is a basic type
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_basic (const GVariantType *type)
{
gchar first_char;
g_return_val_if_fail (g_variant_type_check (type), FALSE);
first_char = g_variant_type_peek_string (type)[0];
switch (first_char)
{
case 'b':
case 'y':
case 'n':
case 'q':
case 'i':
case 'h':
case 'u':
case 't':
case 'x':
case 'd':
case 's':
case 'o':
case 'g':
case '?':
return TRUE;
default:
return FALSE;
}
}
/**
* g_variant_type_is_maybe:
* @type: a #GVariantType
* @returns: %TRUE if @type is a maybe type
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_maybe (const GVariantType *type)
{
g_return_val_if_fail (g_variant_type_check (type), FALSE);
return g_variant_type_peek_string (type)[0] == 'm';
}
/**
* g_variant_type_is_array:
* @type: a #GVariantType
* @returns: %TRUE if @type is an array type
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_array (const GVariantType *type)
{
g_return_val_if_fail (g_variant_type_check (type), FALSE);
return g_variant_type_peek_string (type)[0] == 'a';
}
/**
* g_variant_type_is_tuple:
* @type: a #GVariantType
* @returns: %TRUE if @type is a tuple type
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_tuple (const GVariantType *type)
{
gchar type_char;
g_return_val_if_fail (g_variant_type_check (type), FALSE);
type_char = g_variant_type_peek_string (type)[0];
return type_char == 'r' || type_char == '(';
}
/**
* g_variant_type_is_dict_entry:
* @type: a #GVariantType
* @returns: %TRUE if @type is a dictionary entry type
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_dict_entry (const GVariantType *type)
{
g_return_val_if_fail (g_variant_type_check (type), FALSE);
return g_variant_type_peek_string (type)[0] == '{';
}
/**
* g_variant_type_is_variant:
* @type: a #GVariantType
* @returns: %TRUE if @type is the variant type
*
* Determines if the given @type is the variant type.
*
* Since 2.24
**/
gboolean
g_variant_type_is_variant (const GVariantType *type)
{
g_return_val_if_fail (g_variant_type_check (type), FALSE);
return g_variant_type_peek_string (type)[0] == 'v';
}
/**
* g_variant_type_hash:
* @type: a #GVariantType
* @returns: the hash value
*
* Hashes @type.
*
* The argument type of @type is only #gconstpointer to allow use with
* #GHashTable without function pointer casting. A valid
* #GVariantType must be provided.
*
* Since 2.24
**/
guint
g_variant_type_hash (gconstpointer type)
{
const gchar *type_string;
guint value = 0;
gsize length;
gsize i;
g_return_val_if_fail (g_variant_type_check (type), 0);
type_string = g_variant_type_peek_string (type);
length = g_variant_type_get_string_length (type);
for (i = 0; i < length; i++)
value = (value << 5) - value + type_string[i];
return value;
}
/**
* g_variant_type_equal:
* @type1: a #GVariantType
* @type2: a #GVariantType
* @returns: %TRUE if @type1 and @type2 are exactly equal
*
* Compares @type1 and @type2 for equality.
*
* Only returns %TRUE if the types are exactly equal. Even if one type
* is an indefinite type and the other is a subtype of it, %FALSE will
* be returned if they are not exactly equal. If you want to check for
* subtypes, use g_variant_type_is_subtype_of().
*
* The argument types of @type1 and @type2 are only #gconstpointer to
* allow use with #GHashTable without function pointer casting. For
* both arguments, a valid #GVariantType must be provided.
*
* Since 2.24
**/
gboolean
g_variant_type_equal (gconstpointer type1,
gconstpointer type2)
{
const gchar *string1, *string2;
gsize size1, size2;
g_return_val_if_fail (g_variant_type_check (type1), FALSE);
g_return_val_if_fail (g_variant_type_check (type2), FALSE);
if (type1 == type2)
return TRUE;
size1 = g_variant_type_get_string_length (type1);
size2 = g_variant_type_get_string_length (type2);
if (size1 != size2)
return FALSE;
string1 = g_variant_type_peek_string (type1);
string2 = g_variant_type_peek_string (type2);
return memcmp (string1, string2, size1) == 0;
}
/**
* g_variant_type_is_subtype_of:
* @type: a #GVariantType
* @supertype: a #GVariantType
* @returns: %TRUE if @type is a subtype of @supertype
*
* 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.
*
* Since 2.24
**/
gboolean
g_variant_type_is_subtype_of (const GVariantType *type,
const GVariantType *supertype)
{
const gchar *supertype_string;
const gchar *supertype_end;
const gchar *type_string;
g_return_val_if_fail (g_variant_type_check (type), FALSE);
g_return_val_if_fail (g_variant_type_check (supertype), FALSE);
supertype_string = g_variant_type_peek_string (supertype);
type_string = g_variant_type_peek_string (type);
supertype_end = supertype_string +
g_variant_type_get_string_length (supertype);
/* we know that type and supertype are both well-formed, so it's
* safe to treat this merely as a text processing problem.
*/
while (supertype_string < supertype_end)
{
char supertype_char = *supertype_string++;
if (supertype_char == *type_string)
type_string++;
else if (*type_string == ')')
return FALSE;
else
{
const GVariantType *target_type = (GVariantType *) type_string;
switch (supertype_char)
{
case 'r':
if (!g_variant_type_is_tuple (target_type))
return FALSE;
break;
case '*':
break;
case '?':
if (!g_variant_type_is_basic (target_type))
return FALSE;
break;
default:
return FALSE;
}
type_string += g_variant_type_get_string_length (target_type);
}
}
return TRUE;
}
/**
* g_variant_type_element:
* @type: an array or maybe #GVariantType
* @returns: the element type of @type
*
* Determines the element type of an array or maybe type.
*
* This function may only be used with array or maybe types.
*
* Since 2.24
**/
const GVariantType *
g_variant_type_element (const GVariantType *type)
{
const gchar *type_string;
g_return_val_if_fail (g_variant_type_check (type), NULL);
type_string = g_variant_type_peek_string (type);
g_assert (type_string[0] == 'a' || type_string[0] == 'm');
return (const GVariantType *) &type_string[1];
}
/**
* g_variant_type_first:
* @type: a tuple or dictionary entry #GVariantType
* @returns: the first item type of @type, or %NULL
*
* Determines the first item type of a tuple or dictionary entry
* type.
*
* This function may only be used with tuple or dictionary entry types,
* but must not be used with the generic tuple type
* %G_VARIANT_TYPE_TUPLE.
*
* In the case of a dictionary entry type, this returns the type of
* the key.
*
* %NULL is returned in case of @type being %G_VARIANT_TYPE_UNIT.
*
* This call, together with g_variant_type_next() provides an iterator
* interface over tuple and dictionary entry types.
*
* Since 2.24
**/
const GVariantType *
g_variant_type_first (const GVariantType *type)
{
const gchar *type_string;
g_return_val_if_fail (g_variant_type_check (type), NULL);
type_string = g_variant_type_peek_string (type);
g_assert (type_string[0] == '(' || type_string[0] == '{');
if (type_string[1] == ')')
return NULL;
return (const GVariantType *) &type_string[1];
}
/**
* g_variant_type_next:
* @type: a #GVariantType from a previous call
* @returns: the next #GVariantType after @type, or %NULL
*
* Determines the next item type of a tuple or dictionary entry
* type.
*
* @type must be the result of a previous call to
* g_variant_type_first() or g_variant_type_next().
*
* If called on the key type of a dictionary entry then this call
* returns the value type. If called on the value type of a dictionary
* entry then this call returns %NULL.
*
* For tuples, %NULL is returned when @type is the last item in a tuple.
*
* Since 2.24
**/
const GVariantType *
g_variant_type_next (const GVariantType *type)
{
const gchar *type_string;
g_return_val_if_fail (g_variant_type_check (type), NULL);
type_string = g_variant_type_peek_string (type);
type_string += g_variant_type_get_string_length (type);
if (*type_string == ')' || *type_string == '}')
return NULL;
return (const GVariantType *) type_string;
}
/**
* g_variant_type_n_items:
* @type: a tuple or dictionary entry #GVariantType
* @returns: the number of items in @type
*
* Determines the number of items contained in a tuple or
* dictionary entry type.
*
* This function may only be used with tuple or dictionary entry types,
* but must not be used with the generic tuple type
* %G_VARIANT_TYPE_TUPLE.
*
* In the case of a dictionary entry type, this function will always
* return 2.
*
* Since 2.24
**/
gsize
g_variant_type_n_items (const GVariantType *type)
{
gsize count = 0;
g_return_val_if_fail (g_variant_type_check (type), 0);
for (type = g_variant_type_first (type);
type;
type = g_variant_type_next (type))
count++;
return count;
}
/**
* g_variant_type_key:
* @type: a dictionary entry #GVariantType
* @returns: the key type of the dictionary entry
*
* Determines the key type of a dictionary entry type.
*
* This function may only be used with a dictionary entry type. Other
* than the additional restriction, this call is equivalent to
* g_variant_type_first().
*
* Since 2.24
**/
const GVariantType *
g_variant_type_key (const GVariantType *type)
{
const gchar *type_string;
g_return_val_if_fail (g_variant_type_check (type), NULL);
type_string = g_variant_type_peek_string (type);
g_assert (type_string[0] == '{');
return (const GVariantType *) &type_string[1];
}
/**
* g_variant_type_value:
* @type: a dictionary entry #GVariantType
* @returns: the value type of the dictionary entry
*
* Determines the value type of a dictionary entry type.
*
* This function may only be used with a dictionary entry type.
*
* Since 2.24
**/
const GVariantType *
g_variant_type_value (const GVariantType *type)
{
const gchar *type_string;
g_return_val_if_fail (g_variant_type_check (type), NULL);
type_string = g_variant_type_peek_string (type);
g_assert (type_string[0] == '{');
return g_variant_type_next (g_variant_type_key (type));
}
/**
* g_variant_type_new_tuple:
* @items: an array of #GVariantTypes, one for each item
* @length: the length of @items, or -1
* @returns: a new tuple #GVariantType
*
* Constructs a new tuple type, from @items.
*
* @length is the number of items in @items, or -1 to indicate that
* @items is %NULL-terminated.
*
* It is appropriate to call g_variant_type_free() on the return value.
*
* Since 2.24
**/
static GVariantType *
g_variant_type_new_tuple_slow (const GVariantType * const *items,
gint length)
{
/* the "slow" version is needed in case the static buffer of 1024
* bytes is exceeded when running the normal version. this will
* happen only in truly insane code, so it can be slow.
*/
GString *string;
gsize i;
string = g_string_new ("(");
for (i = 0; i < length; i++)
{
const GVariantType *type;
gsize size;
g_return_val_if_fail (g_variant_type_check (items[i]), NULL);
type = items[i];
size = g_variant_type_get_string_length (type);
g_string_append_len (string, (const gchar *) type, size);
}
g_string_append_c (string, ')');
return (GVariantType *) g_string_free (string, FALSE);
}
GVariantType *
g_variant_type_new_tuple (const GVariantType * const *items,
gint length)
{
char buffer[1024];
gsize offset;
gsize i;
g_return_val_if_fail (length == 0 || items != NULL, NULL);
if (length < 0)
for (length = 0; items[length] != NULL; length++);
offset = 0;
buffer[offset++] = '(';
for (i = 0; i < length; i++)
{
const GVariantType *type;
gsize size;
g_return_val_if_fail (g_variant_type_check (items[i]), NULL);
type = items[i];
size = g_variant_type_get_string_length (type);
if (offset + size >= sizeof buffer) /* leave room for ')' */
return g_variant_type_new_tuple_slow (items, length);
memcpy (&buffer[offset], type, size);
offset += size;
}
g_assert (offset < sizeof buffer);
buffer[offset++] = ')';
return (GVariantType *) g_memdup (buffer, offset);
}
/**
* g_variant_type_new_array:
* @element: a #GVariantType
* @returns: a new array #GVariantType
*
* Constructs the type corresponding to an array of elements of the
* type @type.
*
* It is appropriate to call g_variant_type_free() on the return value.
*
* Since 2.24
**/
GVariantType *
g_variant_type_new_array (const GVariantType *element)
{
gsize size;
gchar *new;
g_return_val_if_fail (g_variant_type_check (element), NULL);
size = g_variant_type_get_string_length (element);
new = g_malloc (size + 1);
new[0] = 'a';
memcpy (new + 1, element, size);
return (GVariantType *) new;
}
/**
* g_variant_type_new_maybe:
* @element: a #GVariantType
* @returns: a new maybe #GVariantType
*
* Constructs the type corresponding to a maybe instance containing
* type @type or Nothing.
*
* It is appropriate to call g_variant_type_free() on the return value.
*
* Since 2.24
**/
GVariantType *
g_variant_type_new_maybe (const GVariantType *element)
{
gsize size;
gchar *new;
g_return_val_if_fail (g_variant_type_check (element), NULL);
size = g_variant_type_get_string_length (element);
new = g_malloc (size + 1);
new[0] = 'm';
memcpy (new + 1, element, size);
return (GVariantType *) new;
}
/**
* g_variant_type_new_dict_entry:
* @key: a basic #GVariantType
* @value: a #GVariantType
* @returns: a new dictionary entry #GVariantType
*
* 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 g_variant_type_free() on the return value.
*
* Since 2.24
**/
GVariantType *
g_variant_type_new_dict_entry (const GVariantType *key,
const GVariantType *value)
{
gsize keysize, valsize;
gchar *new;
g_return_val_if_fail (g_variant_type_check (key), NULL);
g_return_val_if_fail (g_variant_type_check (value), NULL);
keysize = g_variant_type_get_string_length (key);
valsize = g_variant_type_get_string_length (value);
new = g_malloc (1 + keysize + valsize + 1);
new[0] = '{';
memcpy (new + 1, key, keysize);
memcpy (new + 1 + keysize, value, valsize);
new[1 + keysize + valsize] = '}';
return (GVariantType *) new;
}
/* private */
const GVariantType *
g_variant_type_checked_ (const gchar *type_string)
{
g_return_val_if_fail (g_variant_type_string_is_valid (type_string), NULL);
return (const GVariantType *) type_string;
}
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