systemd/man/sd_bus_path_encode.xml
Zbigniew Jędrzejewski-Szmek 3a54a15760 man: use same header for all files
The "include" files had type "book" for some raeason. I don't think this
is meaningful. Let's just use the same everywhere.

$ perl -i -0pe 's^..DOCTYPE (book|refentry) PUBLIC "-//OASIS//DTD DocBook XML V4.[25]//EN"\s+"http^<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"\n  "http^gms' man/*.xml
2019-03-14 14:42:05 +01:00

154 lines
6.7 KiB
XML
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="sd_bus_path_encode" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_path_encode</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_path_encode</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_path_encode</refname>
<refname>sd_bus_path_encode_many</refname>
<refname>sd_bus_path_decode</refname>
<refname>sd_bus_path_decode_many</refname>
<refpurpose>Convert an external identifier into an object path and back</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_path_encode</function></funcdef>
<paramdef>const char *<parameter>prefix</parameter></paramdef>
<paramdef>const char *<parameter>external_id</parameter></paramdef>
<paramdef>char **<parameter>ret_path</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_path_encode_many</function></funcdef>
<paramdef>char **<parameter>out</parameter></paramdef>
<paramdef>const char *<parameter>path_template</parameter></paramdef>
<paramdef></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_path_decode</function></funcdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
<paramdef>const char *<parameter>prefix</parameter></paramdef>
<paramdef>char **<parameter>ret_external_id</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_path_decode_many</function></funcdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
<paramdef>const char *<parameter>path_template</parameter></paramdef>
<paramdef></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_bus_path_encode()</function> and
<function>sd_bus_path_decode()</function> convert external
identifier strings into object paths and back. These functions are
useful to map application-specific string identifiers of any kind
into bus object paths in a simple, reversible and safe way.</para>
<para><function>sd_bus_path_encode()</function> takes a bus path
prefix and an external identifier string as arguments, plus a
place to store the returned bus path string. The bus path prefix
must be a valid bus path, starting with a slash
<literal>/</literal>, and not ending in one. The external
identifier string may be in any format, may be the empty string,
and has no restrictions on the charset — however, it must
always be <constant>NUL</constant>-terminated. The returned string
will be the concatenation of the bus path prefix plus an escaped
version of the external identifier string. This operation may be
reversed with <function>sd_bus_path_decode()</function>. It is
recommended to only use external identifiers that generally
require little escaping to be turned into valid bus path
identifiers (for example, by sticking to a 7-bit ASCII character
set), in order to ensure the resulting bus path is still short and
easily processed.</para>
<para><function>sd_bus_path_decode()</function> reverses the
operation of <function>sd_bus_path_encode()</function> and thus
regenerates an external identifier string from a bus path. It
takes a bus path and a prefix string, plus a place to store the
returned external identifier string. If the bus path does not
start with the specified prefix, 0 is returned and the returned
string is set to <constant>NULL</constant>. Otherwise, the
string following the prefix is unescaped and returned in the
external identifier string.</para>
<para>The escaping used will replace all characters which are
invalid in a bus object path by <literal>_</literal>, followed by a
hexadecimal value. As a special case, the empty string will be
replaced by a lone <literal>_</literal>.</para>
<para><function>sd_bus_path_encode_many()</function> works like
its counterpart <function>sd_bus_path_encode()</function>, but
takes a path template as argument and encodes multiple labels
according to its embedded directives. For each
<literal>%</literal> character found in the template, the caller
must provide a string via varargs, which will be encoded and
embedded at the position of the <literal>%</literal> character.
Any other character in the template is copied verbatim into the
encoded path.</para>
<para><function>sd_bus_path_decode_many()</function> does the
reverse of <function>sd_bus_path_encode_many()</function>. It
decodes the passed object path according to the given
path template. For each <literal>%</literal> character in the
template, the caller must provide an output storage
(<literal>char **</literal>) via varargs. The decoded label
will be stored there. Each <literal>%</literal> character will
only match the current label. It will never match across labels.
Furthermore, only a single directive is allowed per label.
If <literal>NULL</literal> is passed as output storage, the
label is verified but not returned to the caller.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, <function>sd_bus_path_encode()</function>
returns positive or 0, and a valid bus path in the return
argument. On success, <function>sd_bus_path_decode()</function>
returns a positive value if the prefixed matched, or 0 if it
did not. If the prefix matched, the external identifier is returned
in the return parameter. If it did not match, NULL is returned in
the return parameter. On failure, a negative errno-style error
number is returned by either function. The returned strings must
be
<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>'d
by the caller.</para>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>