mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-29 07:58:28 +00:00
c33d89cc64
The PDF versions of the GNU manuals used curved single quotes to
represent grave accent and apostrophe, which made it a pain to cut
and paste code examples from them. Fix the PDF versions to use
grave accent and apostrophe for Lisp source code, keystrokes, etc.
This change does not affect the info files, nor does it affect
ordinary uses of curved single quotes in PDF.
* doc/emacs/docstyle.texi: New file, which specifies treatment for
grave accent and apostrophe, as well as the document encoding.
* doc/emacs/emacs-xtra.texi, doc/emacs/emacs.texi:
* doc/lispintro/emacs-lisp-intro.texi:
* doc/lispref/back.texi, doc/lispref/book-spine.texi:
* doc/lispref/elisp.texi, doc/lispref/lay-flat.texi:
* doc/misc/ada-mode.texi, doc/misc/auth.texi:
* doc/misc/autotype.texi, doc/misc/bovine.texi, doc/misc/calc.texi:
* doc/misc/cc-mode.texi, doc/misc/cl.texi, doc/misc/dbus.texi:
* doc/misc/dired-x.texi, doc/misc/ebrowse.texi, doc/misc/ede.texi:
* doc/misc/ediff.texi, doc/misc/edt.texi, doc/misc/efaq-w32.texi:
* doc/misc/efaq.texi, doc/misc/eieio.texi, doc/misc/emacs-gnutls.texi:
* doc/misc/emacs-mime.texi, doc/misc/epa.texi, doc/misc/erc.texi:
* doc/misc/ert.texi, doc/misc/eshell.texi, doc/misc/eudc.texi:
* doc/misc/eww.texi, doc/misc/flymake.texi, doc/misc/forms.texi:
* doc/misc/gnus-coding.texi, doc/misc/gnus-faq.texi:
* doc/misc/gnus.texi, doc/misc/htmlfontify.texi:
* doc/misc/idlwave.texi, doc/misc/ido.texi, doc/misc/info.texi:
* doc/misc/mairix-el.texi, doc/misc/message.texi, doc/misc/mh-e.texi:
* doc/misc/newsticker.texi, doc/misc/nxml-mode.texi:
* doc/misc/octave-mode.texi, doc/misc/org.texi, doc/misc/pcl-cvs.texi:
* doc/misc/pgg.texi, doc/misc/rcirc.texi, doc/misc/reftex.texi:
* doc/misc/remember.texi, doc/misc/sasl.texi, doc/misc/sc.texi:
* doc/misc/semantic.texi, doc/misc/ses.texi, doc/misc/sieve.texi:
* doc/misc/smtpmail.texi, doc/misc/speedbar.texi:
* doc/misc/srecode.texi, doc/misc/todo-mode.texi, doc/misc/tramp.texi:
* doc/misc/url.texi, doc/misc/vhdl-mode.texi, doc/misc/vip.texi:
* doc/misc/viper.texi, doc/misc/widget.texi, doc/misc/wisent.texi:
* doc/misc/woman.texi:
Use it instead of '@documentencoding UTF-8', to lessen the need for
global changes like this in the future.
* doc/emacs/Makefile.in (EMACS_XTRA):
* doc/lispintro/Makefile.in (srcs):
* doc/lispref/Makefile.in (srcs):
Add dependency on docstyle.texi.
* doc/misc/Makefile.in (style): New macro.
(${buildinfodir}/%.info, %.dvi, %.pdf, %.html)
(${buildinfodir}/ccmode.info, ${buildinfodir}/efaq%.info, gnus_deps):
Use it.
2042 lines
71 KiB
Plaintext
2042 lines
71 KiB
Plaintext
\input texinfo @c -*- coding: utf-8 -*-
|
|
@setfilename ../../info/dbus.info
|
|
@c %**start of header
|
|
@settitle Using of D-Bus
|
|
@include docstyle.texi
|
|
@c @setchapternewpage odd
|
|
@c %**end of header
|
|
|
|
@syncodeindex vr cp
|
|
@syncodeindex fn cp
|
|
|
|
@copying
|
|
Copyright @copyright{} 2007--2015 Free Software Foundation, Inc.
|
|
|
|
@quotation
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
|
any later version published by the Free Software Foundation; with no
|
|
Invariant Sections, with the Front-Cover Texts being ``A GNU Manual'',
|
|
and with the Back-Cover Texts as in (a) below. A copy of the license
|
|
is included in the section entitled ``GNU Free Documentation License''.
|
|
|
|
(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
|
|
modify this GNU manual.''
|
|
@end quotation
|
|
@end copying
|
|
|
|
@dircategory Emacs lisp libraries
|
|
@direntry
|
|
* D-Bus: (dbus). Using D-Bus in Emacs.
|
|
@end direntry
|
|
|
|
@titlepage
|
|
@title Using D-Bus in Emacs
|
|
@page
|
|
@vskip 0pt plus 1filll
|
|
@insertcopying
|
|
@end titlepage
|
|
|
|
|
|
@contents
|
|
|
|
|
|
@node Top, Overview, (dir), (dir)
|
|
@top D-Bus integration in Emacs
|
|
|
|
This manual documents an API for usage of D-Bus in Emacs. D-Bus is a
|
|
message bus system, a simple way for applications to talk to one
|
|
another. An overview of D-Bus can be found at
|
|
@uref{http://dbus.freedesktop.org/}.
|
|
|
|
@ifnottex
|
|
@insertcopying
|
|
@end ifnottex
|
|
|
|
@menu
|
|
* Overview:: An overview of D-Bus.
|
|
* Inspection:: Inspection of D-Bus services.
|
|
* Type Conversion:: Mapping Lisp types and D-Bus types.
|
|
* Synchronous Methods:: Calling methods in a blocking way.
|
|
* Asynchronous Methods:: Calling methods non-blocking.
|
|
* Receiving Method Calls:: Offering own methods.
|
|
* Signals:: Sending and receiving signals.
|
|
* Alternative Buses:: Alternative buses and environments.
|
|
* Errors and Events:: Errors and events.
|
|
* Index:: Index including concepts, functions, variables.
|
|
|
|
* GNU Free Documentation License:: The license for this documentation.
|
|
@end menu
|
|
|
|
|
|
@node Overview
|
|
@chapter An overview of D-Bus
|
|
@cindex overview
|
|
|
|
D-Bus is an inter-process communication mechanism for applications
|
|
residing on the same host. The communication is based on
|
|
@dfn{messages}. Data in the messages is carried in a structured way,
|
|
it is not just a byte stream.
|
|
|
|
The communication is connection oriented to two kinds of message
|
|
buses: a so called @dfn{system bus}, and a @dfn{session bus}. On a
|
|
given machine, there is always one single system bus for miscellaneous
|
|
system-wide communication, like changing of hardware configuration.
|
|
On the other hand, the session bus is always related to a single
|
|
user's session.
|
|
|
|
Every client application, which is connected to a bus, registers under
|
|
a @dfn{unique name} at the bus. This name is used for identifying the
|
|
client application. Such a unique name starts always with a colon,
|
|
and looks like @samp{:1.42}.
|
|
|
|
Additionally, a client application can register itself to a so called
|
|
@dfn{known name}, which is a series of identifiers separated by dots,
|
|
as in @samp{org.gnu.Emacs}. If several applications register to the
|
|
same known name, these registrations are queued, and only the first
|
|
application which has registered for the known name is reachable via
|
|
this name. If this application disconnects from the bus, the next
|
|
queued unique name becomes the owner of this known name.
|
|
|
|
An application can install one or several objects under its name.
|
|
Such objects are identified by an @dfn{object path}, which looks
|
|
similar to paths in a filesystem. An example of such an object path
|
|
could be @samp{/org/gnu/Emacs/}.
|
|
|
|
Applications might send a request to an object, that means sending a
|
|
message with some data as input parameters, and receiving a message
|
|
from that object with the result of this message, the output
|
|
parameters. Such a request is called @dfn{method} in D-Bus.
|
|
|
|
The other form of communication are @dfn{signals}. The underlying
|
|
message is emitted from an object and will be received by all other
|
|
applications which have registered for such a signal.
|
|
|
|
All methods and signals an object supports are called @dfn{interface}
|
|
of the object. Interfaces are specified under a hierarchical name in
|
|
D-Bus; an object can support several interfaces. Such an interface
|
|
name could be @samp{org.gnu.Emacs.TextEditor} or
|
|
@samp{org.gnu.Emacs.FileManager}.
|
|
|
|
|
|
@node Inspection
|
|
@chapter Inspection of D-Bus services.
|
|
@cindex inspection
|
|
|
|
@menu
|
|
* Version:: Determining the D-Bus version.
|
|
* Bus names:: Discovering D-Bus names.
|
|
* Introspection:: Knowing the details of D-Bus services.
|
|
* Nodes and Interfaces:: Detecting object paths and interfaces.
|
|
* Methods and Signal:: Applying the functionality.
|
|
* Properties and Annotations:: What else to know about interfaces.
|
|
* Arguments and Signatures:: The final details.
|
|
@end menu
|
|
|
|
|
|
@node Version
|
|
@section D-Bus version.
|
|
|
|
D-Bus has evolved over the years. New features have been added with
|
|
new D-Bus versions. There are two variables, which allow to determine
|
|
the used D-Bus version.
|
|
|
|
@defvar dbus-compiled-version
|
|
This variable, a string, determines the version of D-Bus Emacs is
|
|
compiled against. If it cannot be determined the value is @code{nil}.
|
|
@end defvar
|
|
|
|
@defvar dbus-runtime-version
|
|
The other D-Bus version to be checked is the version of D-Bus Emacs
|
|
runs with. This string can be different from @code{dbus-compiled-version}.
|
|
It is also @code{nil}, if it cannot be determined at runtime.
|
|
@end defvar
|
|
|
|
|
|
@node Bus names
|
|
@section Bus names.
|
|
|
|
There are several basic functions which inspect the buses for
|
|
registered names. Internally they use the basic interface
|
|
@samp{org.freedesktop.DBus}, which is supported by all objects of a bus.
|
|
|
|
@defun dbus-list-activatable-names &optional bus
|
|
This function returns the D-Bus service names, which can be activated
|
|
for @var{bus}. It must be either the symbol @code{:system} (the
|
|
default) or the symbol @code{:session}. An activatable service is
|
|
described in a service registration file. Under GNU/Linux, such files
|
|
are located at @file{/usr/share/dbus-1/system-services/} (for the
|
|
@code{:system} bus) or @file{/usr/share/dbus-1/services/}. An
|
|
activatable service is not necessarily registered at @var{bus} at already.
|
|
|
|
The result is a list of strings, which is @code{nil} when there are no
|
|
activatable service names at all. Example:
|
|
|
|
@lisp
|
|
;; Check, whether the document viewer can be accessed via D-Bus.
|
|
(member "org.gnome.evince.Daemon"
|
|
(dbus-list-activatable-names :session))
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-list-names bus
|
|
All service names, which are registered at D-Bus @var{bus}, are
|
|
returned. The result is a list of strings, which is @code{nil} when
|
|
there are no registered service names at all. Well known names are
|
|
strings like @samp{org.freedesktop.DBus}. Names starting with
|
|
@samp{:} are unique names for services.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
@end defun
|
|
|
|
@defun dbus-list-known-names bus
|
|
Retrieves all registered services which correspond to a known name in @var{bus}.
|
|
A service has a known name if it doesn't start with @samp{:}. The
|
|
result is a list of strings, which is @code{nil} when there are no
|
|
known names at all.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
@end defun
|
|
|
|
@defun dbus-list-queued-owners bus service
|
|
For a given service, registered at D-Bus @var{bus} under the name
|
|
@var{service}, all queued unique names are returned. The result is a
|
|
list of strings, or @code{nil} when there are no queued names for
|
|
@var{service} at all.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}. @var{service} must be a known service name as
|
|
string.
|
|
@end defun
|
|
|
|
@defun dbus-get-name-owner bus service
|
|
For a given service, registered at D-Bus @var{bus} under the name
|
|
@var{service}, the unique name of the name owner is returned. The
|
|
result is a string, or @code{nil} when there exist no name owner of
|
|
@var{service}.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}. @var{service} must be a known service name as
|
|
string.
|
|
@end defun
|
|
|
|
@defun dbus-ping bus service &optional timeout
|
|
Check whether the service name @var{service} is registered at D-Bus
|
|
@var{bus}. @var{service} might not have been started yet, it is
|
|
autostarted if possible. The result is either @code{t} or @code{nil}.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}. @var{service} must be a string. @var{timeout}, a
|
|
nonnegative integer, specifies the maximum number of milliseconds
|
|
@code{dbus-ping} must return. The default value is 25,000. Example:
|
|
|
|
@lisp
|
|
(message
|
|
"%s screensaver on board."
|
|
(cond
|
|
((dbus-ping :session "org.gnome.ScreenSaver" 100) "Gnome")
|
|
((dbus-ping :session "org.freedesktop.ScreenSaver" 100) "KDE")
|
|
(t "No")))
|
|
@end lisp
|
|
|
|
If it shall be checked whether @var{service} is already running
|
|
without autostarting it, one shall apply
|
|
|
|
@lisp
|
|
(member service (dbus-list-known-names bus))
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-get-unique-name bus
|
|
The unique name, under which Emacs is registered at D-Bus @var{bus},
|
|
is returned as string.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
@end defun
|
|
|
|
|
|
@node Introspection
|
|
@section Knowing the details of D-Bus services.
|
|
|
|
D-Bus services publish their interfaces. This can be retrieved and
|
|
analyzed during runtime, in order to understand the used
|
|
implementation.
|
|
|
|
The resulting introspection data are in XML format. The root
|
|
introspection element is always a @code{node} element. It might have
|
|
a @code{name} attribute, which denotes the (absolute) object path an
|
|
interface is introspected.
|
|
|
|
The root @code{node} element may have @code{node} and @code{interface}
|
|
children. A child @code{node} element must have a @code{name}
|
|
attribute, this case it is the relative object path to the root
|
|
@code{node} element.
|
|
|
|
An @code{interface} element has just one attribute, @code{name}, which
|
|
is the full name of that interface. The default interface
|
|
@samp{org.freedesktop.DBus.Introspectable} is always present. Example:
|
|
|
|
@example
|
|
<node name="/org/bluez">
|
|
<interface name="org.freedesktop.DBus.Introspectable">
|
|
@dots{}
|
|
</interface>
|
|
<interface name="org.bluez.Manager">
|
|
@dots{}
|
|
</interface>
|
|
<interface name="org.bluez.Database">
|
|
@dots{}
|
|
</interface>
|
|
<interface name="org.bluez.Security">
|
|
@dots{}
|
|
</interface>
|
|
<node name="service_audio"/>
|
|
<node name="service_input"/>
|
|
<node name="service_network"/>
|
|
<node name="service_serial"/>
|
|
</node>
|
|
@end example
|
|
|
|
Children of an @code{interface} element can be @code{method},
|
|
@code{signal} and @code{property} elements. A @code{method} element
|
|
stands for a D-Bus method of the surrounding interface. The element
|
|
itself has a @code{name} attribute, showing the method name. Children
|
|
elements @code{arg} stand for the arguments of a method. Example:
|
|
|
|
@example
|
|
<method name="ResolveHostName">
|
|
<arg name="interface" type="i" direction="in"/>
|
|
<arg name="protocol" type="i" direction="in"/>
|
|
<arg name="name" type="s" direction="in"/>
|
|
<arg name="aprotocol" type="i" direction="in"/>
|
|
<arg name="flags" type="u" direction="in"/>
|
|
<arg name="interface" type="i" direction="out"/>
|
|
<arg name="protocol" type="i" direction="out"/>
|
|
<arg name="name" type="s" direction="out"/>
|
|
<arg name="aprotocol" type="i" direction="out"/>
|
|
<arg name="address" type="s" direction="out"/>
|
|
<arg name="flags" type="u" direction="out"/>
|
|
</method>
|
|
@end example
|
|
|
|
@code{arg} elements can have the attributes @code{name}, @code{type}
|
|
and @code{direction}. The @code{name} attribute is optional. The
|
|
@code{type} attribute stands for the @dfn{signature} of the argument
|
|
in D-Bus. For a discussion of D-Bus types and their Lisp
|
|
representation see @ref{Type Conversion}.@footnote{D-Bus signatures
|
|
are explained in the D-Bus specification
|
|
@uref{http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-signatures}.}
|
|
The @code{direction} attribute of an @code{arg} element can be only
|
|
@samp{in} or @samp{out}; in case it is omitted, it defaults to
|
|
@samp{in}.
|
|
|
|
A @code{signal} element of an @code{interface} has a similar
|
|
structure. The @code{direction} attribute of an @code{arg} child
|
|
element can be only @samp{out} here; which is also the default value.
|
|
Example:
|
|
|
|
@example
|
|
<signal name="StateChanged">
|
|
<arg name="state" type="i"/>
|
|
<arg name="error" type="s"/>
|
|
</signal>
|
|
@end example
|
|
|
|
A @code{property} element has no @code{arg} child
|
|
element. It just has the attributes @code{name}, @code{type} and
|
|
@code{access}, which are all mandatory. The @code{access} attribute
|
|
allows the values @samp{readwrite}, @samp{read}, and @samp{write}.
|
|
Example:
|
|
|
|
@example
|
|
<property name="Status" type="u" direction="read"/>
|
|
@end example
|
|
|
|
@code{annotation} elements can be children of @code{interface},
|
|
@code{method}, @code{signal}, and @code{property} elements. Unlike
|
|
properties, which can change their values during lifetime of a D-Bus
|
|
object, annotations are static. Often they are used for code
|
|
generators of D-Bus language bindings. Example:
|
|
|
|
@example
|
|
<annotation name="de.berlios.Pinot.GetStatistics" value="pinotDBus"/>
|
|
@end example
|
|
|
|
Annotations have just @code{name} and @code{value} attributes, both
|
|
must be strings.
|
|
|
|
@defun dbus-introspect bus service path
|
|
This function returns all interfaces and sub-nodes of @var{service},
|
|
registered at object path @var{path} at bus @var{bus}.
|
|
|
|
@var{bus} must be either the symbol @code{:system} or the symbol
|
|
@code{:session}. @var{service} must be a known service name, and
|
|
@var{path} must be a valid object path. The last two parameters are
|
|
strings. The result, the introspection data, is a string in XML
|
|
format. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect
|
|
:system "org.freedesktop.Hal"
|
|
"/org/freedesktop/Hal/devices/computer")
|
|
|
|
@result{} "<!DOCTYPE node PUBLIC
|
|
"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
|
|
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
|
|
<node>
|
|
<interface name="org.freedesktop.Hal.Device">
|
|
<method name="GetAllProperties">
|
|
<arg name="properties" direction="out" type="a@{sv@}"/>
|
|
</method>
|
|
@dots{}
|
|
<signal name="PropertyModified">
|
|
<arg name="num_updates" type="i"/>
|
|
<arg name="updates" type="a(sbb)"/>
|
|
</signal>
|
|
</interface>
|
|
@dots{}
|
|
</node>"
|
|
@end lisp
|
|
|
|
This example informs us, that the service @samp{org.freedesktop.Hal}
|
|
at object path @samp{/org/freedesktop/Hal/devices/computer} offers the
|
|
interface @samp{org.freedesktop.Hal.Device} (and 2 other interfaces
|
|
not documented here). This interface contains the method
|
|
@samp{GetAllProperties}, which needs no input parameters, but returns
|
|
as output parameter an array of dictionary entries (key-value pairs).
|
|
Every dictionary entry has a string as key, and a variant as value.
|
|
|
|
The interface offers also a signal, which returns 2 parameters: an
|
|
integer, and an array consisting of elements which are a struct of a
|
|
string and 2 boolean values.@footnote{ The interfaces of the service
|
|
@samp{org.freedesktop.Hal} are described in
|
|
@c Previous link is gone. Since HAL is now obsolete, this URL
|
|
@c (unchanged in ~ 4 years) feels like it might go too...
|
|
@uref{http://people.freedesktop.org/~dkukawka/hal-spec-git/hal-spec.html#interfaces,
|
|
the HAL specification}.}
|
|
@end defun
|
|
|
|
@defun dbus-introspect-xml bus service path
|
|
This function has the same intention as function
|
|
@code{dbus-introspect}. The returned value is a parsed XML tree,
|
|
which can be used for further analysis. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-xml
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main")
|
|
|
|
@result{} (node ((name . "/org/freedesktop/xesam/searcher/main"))
|
|
(interface ((name . "org.freedesktop.xesam.Search"))
|
|
(method ((name . "GetHitData"))
|
|
(arg ((name . "search") (type . "s") (direction . "in")))
|
|
(arg ((name . "hit_ids") (type . "au") (direction . "in")))
|
|
(arg ((name . "fields") (type . "as") (direction . "in")))
|
|
(arg ((name . "hit_data") (type . "aav") (direction . "out")))
|
|
)
|
|
@dots{}
|
|
(signal ((name . "HitsAdded"))
|
|
(arg ((name . "search") (type . "s")))
|
|
(arg ((name . "count") (type . "u")))
|
|
)
|
|
)
|
|
@dots{}
|
|
)
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-attribute object attribute
|
|
It returns the @var{attribute} value of a D-Bus introspection
|
|
@var{object}. @var{object} can be every subtree of a parsed XML tree
|
|
as retrieved with @code{dbus-introspect-xml}. @var{attribute} must be
|
|
a string according to the attribute names in the D-Bus specification.
|
|
Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-attribute
|
|
(dbus-introspect-xml :system "org.freedesktop.SystemToolsBackends"
|
|
"/org/freedesktop/SystemToolsBackends/UsersConfig")
|
|
"name")
|
|
|
|
@result{} "/org/freedesktop/SystemToolsBackends/UsersConfig"
|
|
@end lisp
|
|
|
|
If @var{object} has no @var{attribute}, the function returns
|
|
@code{nil}.
|
|
@end defun
|
|
|
|
|
|
@node Nodes and Interfaces
|
|
@section Detecting object paths and interfaces.
|
|
|
|
The first elements, to be introspected for a D-Bus object, are further
|
|
object paths and interfaces.
|
|
|
|
@defun dbus-introspect-get-node-names bus service path
|
|
All node names of @var{service} in D-Bus @var{bus} at object path
|
|
@var{path} are returned as list of strings. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-node-names
|
|
:session "org.gnome.seahorse" "/org/gnome/seahorse")
|
|
|
|
@result{} ("crypto" "keys")
|
|
@end lisp
|
|
|
|
The node names stand for further object paths of the D-Bus
|
|
@var{service}, relative to @var{path}. In the example,
|
|
@samp{/org/gnome/seahorse/crypto} and @samp{/org/gnome/seahorse/keys}
|
|
are also object paths of the D-Bus service @samp{org.gnome.seahorse}.
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-all-nodes bus service path
|
|
This function returns all node names of @var{service} in D-Bus
|
|
@var{bus} at object path @var{path}. It returns a list of strings
|
|
with all object paths of @var{service}, starting at @var{path}.
|
|
Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-all-nodes :session "org.gnome.seahorse" "/")
|
|
|
|
@result{} ("/" "/org" "/org/gnome" "/org/gnome/seahorse"
|
|
"/org/gnome/seahorse/crypto"
|
|
"/org/gnome/seahorse/keys"
|
|
"/org/gnome/seahorse/keys/openpgp"
|
|
"/org/gnome/seahorse/keys/openpgp/local"
|
|
"/org/gnome/seahorse/keys/openssh"
|
|
"/org/gnome/seahorse/keys/openssh/local")
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-interface-names bus service path
|
|
There will be returned a list strings of all interface names of
|
|
@var{service} in D-Bus @var{bus} at object path @var{path}. This list
|
|
will contain the default interface @samp{org.freedesktop.DBus.Introspectable}.
|
|
|
|
Another default interface is @samp{org.freedesktop.DBus.Properties}.
|
|
If present, @code{interface} elements can also have @code{property}
|
|
children. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-interface-names
|
|
:system "org.freedesktop.Hal"
|
|
"/org/freedesktop/Hal/devices/computer")
|
|
|
|
@result{} ("org.freedesktop.DBus.Introspectable"
|
|
"org.freedesktop.Hal.Device"
|
|
"org.freedesktop.Hal.Device.SystemPowerManagement"
|
|
"org.freedesktop.Hal.Device.CPUFreq")
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-interface bus service path interface
|
|
Return @var{interface} of @var{service} in D-Bus @var{bus} at object
|
|
path @var{path}. The return value is an XML element. @var{interface}
|
|
must be a string, element of the list returned by
|
|
@code{dbus-introspect-get-interface-names}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-interface
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search")
|
|
|
|
@result{} (interface ((name . "org.freedesktop.xesam.Search"))
|
|
(method ((name . "GetHitData"))
|
|
(arg ((name . "search") (type . "s") (direction . "in")))
|
|
(arg ((name . "hit_ids") (type . "au") (direction . "in")))
|
|
(arg ((name . "fields") (type . "as") (direction . "in")))
|
|
(arg ((name . "hit_data") (type . "aav") (direction . "out")))
|
|
)
|
|
@dots{}
|
|
(signal ((name . "HitsAdded"))
|
|
(arg ((name . "search") (type . "s")))
|
|
(arg ((name . "count") (type . "u")))
|
|
)
|
|
)
|
|
@end lisp
|
|
@end defun
|
|
|
|
@noindent
|
|
With these functions, it is possible to retrieve all introspection
|
|
data from a running system:
|
|
|
|
@lisp
|
|
(with-current-buffer (switch-to-buffer "*introspect*")
|
|
(erase-buffer)
|
|
(dolist (service (dbus-list-known-names :session))
|
|
(dolist (path (dbus-introspect-get-all-nodes :session service "/"))
|
|
;; We want to introspect only elements, which have more than
|
|
;; the default interface "org.freedesktop.DBus.Introspectable".
|
|
(when (delete
|
|
"org.freedesktop.DBus.Introspectable"
|
|
(dbus-introspect-get-interface-names :session service path))
|
|
(insert (message "\nservice: \"%s\" path: \"%s\"\n" service path)
|
|
(dbus-introspect :session service path))
|
|
(redisplay t)))))
|
|
@end lisp
|
|
|
|
|
|
@node Methods and Signal
|
|
@section Applying the functionality.
|
|
|
|
Methods and signals are the communication means to D-Bus. The
|
|
following functions return their specifications.
|
|
|
|
@defun dbus-introspect-get-method-names bus service path interface
|
|
Return a list of strings of all method names of @var{interface} of
|
|
@var{service} in D-Bus @var{bus} at object path @var{path}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-method-names
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search")
|
|
|
|
@result{} ("GetState" "StartSearch" "GetHitCount" "GetHits" "NewSession"
|
|
"CloseSession" "GetHitData" "SetProperty" "NewSearch"
|
|
"GetProperty" "CloseSearch")
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-method bus service path interface method
|
|
This function returns @var{method} of @var{interface} as XML element.
|
|
It must be located at @var{service} in D-Bus @var{bus} at object path
|
|
@var{path}. @var{method} must be a string, element of the list
|
|
returned by @code{dbus-introspect-get-method-names}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-method
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search" "GetHitData")
|
|
|
|
@result{} (method ((name . "GetHitData"))
|
|
(arg ((name . "search") (type . "s") (direction . "in")))
|
|
(arg ((name . "hit_ids") (type . "au") (direction . "in")))
|
|
(arg ((name . "fields") (type . "as") (direction . "in")))
|
|
(arg ((name . "hit_data") (type . "aav") (direction . "out")))
|
|
)
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-signal-names bus service path interface
|
|
Return a list of strings of all signal names of @var{interface} of
|
|
@var{service} in D-Bus @var{bus} at object path @var{path}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-signal-names
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search")
|
|
|
|
@result{} ("StateChanged" "SearchDone" "HitsModified"
|
|
"HitsRemoved" "HitsAdded")
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-signal bus service path interface signal
|
|
This function returns @var{signal} of @var{interface} as XML element.
|
|
It must be located at @var{service} in D-Bus @var{bus} at object path
|
|
@var{path}. @var{signal} must be a string, element of the list
|
|
returned by @code{dbus-introspect-get-signal-names}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-signal
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search" "HitsAdded")
|
|
|
|
@result{} (signal ((name . "HitsAdded"))
|
|
(arg ((name . "search") (type . "s")))
|
|
(arg ((name . "count") (type . "u")))
|
|
)
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Properties and Annotations
|
|
@section What else to know about interfaces.
|
|
|
|
Interfaces can have properties. These can be exposed via the
|
|
@samp{org.freedesktop.DBus.Properties} interface@footnote{See
|
|
@uref{http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-properties}}.
|
|
That is, properties can be retrieved and changed during lifetime of an
|
|
element.
|
|
|
|
A generalized interface is
|
|
@samp{org.freedesktop.DBus.Objectmanager}@footnote{See
|
|
@uref{http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-objectmanager}},
|
|
which returns objects, their interfaces and properties for a given
|
|
service in just one call.
|
|
|
|
Annotations, on the other hand, are static values for an element.
|
|
Often, they are used to instruct generators, how to generate code from
|
|
the interface for a given language binding.
|
|
|
|
@defun dbus-introspect-get-property-names bus service path interface
|
|
Return a list of strings with all property names of @var{interface} of
|
|
@var{service} in D-Bus @var{bus} at object path @var{path}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-property-names
|
|
:session "org.kde.kded" "/modules/networkstatus"
|
|
"org.kde.Solid.Networking.Client")
|
|
|
|
@result{} ("Status")
|
|
@end lisp
|
|
|
|
If an interface declares properties, the corresponding element supports
|
|
also the @samp{org.freedesktop.DBus.Properties} interface.
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-property bus service path interface property
|
|
This function returns @var{property} of @var{interface} as XML element.
|
|
It must be located at @var{service} in D-Bus @var{bus} at object path
|
|
@var{path}. @var{property} must be a string, element of the list
|
|
returned by @code{dbus-introspect-get-property-names}.
|
|
|
|
A @var{property} value can be retrieved by the function
|
|
@code{dbus-introspect-get-attribute}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-property
|
|
:session "org.kde.kded" "/modules/networkstatus"
|
|
"org.kde.Solid.Networking.Client" "Status")
|
|
|
|
@result{} (property ((access . "read") (type . "u") (name . "Status")))
|
|
|
|
(dbus-introspect-get-attribute
|
|
(dbus-introspect-get-property
|
|
:session "org.kde.kded" "/modules/networkstatus"
|
|
"org.kde.Solid.Networking.Client" "Status")
|
|
"access")
|
|
|
|
@result{} "read"
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-get-property bus service path interface property
|
|
This function returns the value of @var{property} of @var{interface}.
|
|
It will be checked at @var{bus}, @var{service}, @var{path}. The
|
|
result can be any valid D-Bus value, or @code{nil} if there is no
|
|
@var{property}. Example:
|
|
|
|
@lisp
|
|
(dbus-get-property
|
|
:session "org.kde.kded" "/modules/networkstatus"
|
|
"org.kde.Solid.Networking.Client" "Status")
|
|
|
|
@result{} 4
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-set-property bus service path interface property value
|
|
Set value of @var{property} of @var{interface} to @var{value}. It
|
|
will be checked at @var{bus}, @var{service}, @var{path}. When the
|
|
value has been set successful, the result is @var{value}. Otherwise,
|
|
@code{nil} is returned. Example:
|
|
|
|
@lisp
|
|
(dbus-set-property
|
|
:session "org.kde.kaccess" "/MainApplication"
|
|
"com.trolltech.Qt.QApplication" "doubleClickInterval" 500)
|
|
|
|
@result{} 500
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-get-all-properties bus service path interface
|
|
This function returns all properties of @var{interface}. It will be
|
|
checked at @var{bus}, @var{service}, @var{path}. The result is a list
|
|
of cons. Every cons contains the name of the property, and its value.
|
|
If there are no properties, @code{nil} is returned. Example:
|
|
|
|
@lisp
|
|
(dbus-get-all-properties
|
|
:session "org.kde.kaccess" "/MainApplication"
|
|
"com.trolltech.Qt.QApplication")
|
|
|
|
@result{} (("cursorFlashTime" . 1000) ("doubleClickInterval" . 500)
|
|
("keyboardInputInterval" . 400) ("wheelScrollLines" . 3)
|
|
("globalStrut" 0 0) ("startDragTime" . 500)
|
|
("startDragDistance" . 4) ("quitOnLastWindowClosed" . t)
|
|
("styleSheet" . ""))
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-get-all-managed-objects bus service path
|
|
This function returns all objects at @var{bus}, @var{service},
|
|
@var{path}, and the children of @var{path}. The result is a list of
|
|
objects. Every object is a cons of an existing path name, and the
|
|
list of available interface objects. An interface object is another
|
|
cons, which car is the interface name, and the cdr is the list of
|
|
properties as returned by @code{dbus-get-all-properties} for that path
|
|
and interface. Example:
|
|
|
|
@lisp
|
|
(dbus-get-all-managed-objects
|
|
:session "org.gnome.SettingsDaemon" "/")
|
|
|
|
@result{} (("/org/gnome/SettingsDaemon/MediaKeys"
|
|
("org.gnome.SettingsDaemon.MediaKeys")
|
|
("org.freedesktop.DBus.Peer")
|
|
("org.freedesktop.DBus.Introspectable")
|
|
("org.freedesktop.DBus.Properties")
|
|
("org.freedesktop.DBus.ObjectManager"))
|
|
("/org/gnome/SettingsDaemon/Power"
|
|
("org.gnome.SettingsDaemon.Power.Keyboard")
|
|
("org.gnome.SettingsDaemon.Power.Screen")
|
|
("org.gnome.SettingsDaemon.Power"
|
|
("Icon" . ". GThemedIcon battery-full-charged-symbolic ")
|
|
("Tooltip" . "Laptop battery is charged"))
|
|
("org.freedesktop.DBus.Peer")
|
|
("org.freedesktop.DBus.Introspectable")
|
|
("org.freedesktop.DBus.Properties")
|
|
("org.freedesktop.DBus.ObjectManager"))
|
|
@dots{})
|
|
@end lisp
|
|
|
|
If possible, @samp{org.freedesktop.DBus.ObjectManager.GetManagedObjects}
|
|
is used for retrieving the information. Otherwise, the information
|
|
is collected via @samp{org.freedesktop.DBus.Introspectable.Introspect}
|
|
and @samp{org.freedesktop.DBus.Properties.GetAll}, which is slow.
|
|
|
|
An overview of all existing object paths, their interfaces and
|
|
properties could be retrieved by the following code:
|
|
|
|
@lisp
|
|
(with-current-buffer (switch-to-buffer "*objectmanager*")
|
|
(erase-buffer)
|
|
(let (result)
|
|
(dolist (service (dbus-list-known-names :session) result)
|
|
(message "%s" service)
|
|
(add-to-list
|
|
'result
|
|
(cons service
|
|
(dbus-get-all-managed-objects :session service "/"))))
|
|
(insert (message "%s" (pp result)))
|
|
(redisplay t)))
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-annotation-names bus service path interface &optional name
|
|
Return a list of all annotation names as list of strings. If
|
|
@var{name} is @code{nil}, the annotations are children of
|
|
@var{interface}, otherwise @var{name} must be a @code{method},
|
|
@code{signal}, or @code{property} XML element, where the annotations
|
|
belong to. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-annotation-names
|
|
:session "de.berlios.Pinot" "/de/berlios/Pinot"
|
|
"de.berlios.Pinot" "GetStatistics")
|
|
|
|
@result{} ("de.berlios.Pinot.GetStatistics")
|
|
@end lisp
|
|
|
|
Default annotation names@footnote{See
|
|
@uref{http://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format}}
|
|
are
|
|
|
|
@table @samp
|
|
@item org.freedesktop.DBus.Deprecated
|
|
Whether or not the entity is deprecated; defaults to @code{nil}
|
|
|
|
@item org.freedesktop.DBus.GLib.CSymbol
|
|
The C symbol; may be used for @code{methods} and @code{interfaces}
|
|
|
|
@item org.freedesktop.DBus.Method.NoReply
|
|
If set, don't expect a reply to the @code{method} call; defaults to @code{nil}
|
|
@end table
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-annotation bus service path interface name annotation
|
|
Return annotation @var{ANNOTATION} as XML object. If @var{name} is
|
|
@code{nil}, @var{ANNOTATION} is a child of @var{interface}, otherwise
|
|
@var{name} must be the name of a @code{method}, @code{signal}, or
|
|
@code{property} XML element, where the @var{ANNOTATION} belongs to.
|
|
|
|
An attribute value can be retrieved by
|
|
@code{dbus-introspect-get-attribute}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-annotation
|
|
:session "de.berlios.Pinot" "/de/berlios/Pinot"
|
|
"de.berlios.Pinot" "GetStatistics"
|
|
"de.berlios.Pinot.GetStatistics")
|
|
|
|
@result{} (annotation ((name . "de.berlios.Pinot.GetStatistics")
|
|
(value . "pinotDBus")))
|
|
|
|
(dbus-introspect-get-attribute
|
|
(dbus-introspect-get-annotation
|
|
:session "de.berlios.Pinot" "/de/berlios/Pinot"
|
|
"de.berlios.Pinot" "GetStatistics"
|
|
"de.berlios.Pinot.GetStatistics")
|
|
"value")
|
|
|
|
@result{} "pinotDBus"
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Arguments and Signatures
|
|
@section The final details.
|
|
|
|
Methods and signals have arguments. They are described in the
|
|
@code{arg} XML elements.
|
|
|
|
@defun dbus-introspect-get-argument-names bus service path interface name
|
|
Return a list of all argument names as list of strings. @var{name}
|
|
must be a @code{method} or @code{signal} XML element. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-argument-names
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search" "GetHitData")
|
|
|
|
@result{} ("search" "hit_ids" "fields" "hit_data")
|
|
@end lisp
|
|
|
|
Argument names are optional; the function can return @code{nil}
|
|
therefore, even if the method or signal has arguments.
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-argument bus service path interface name arg
|
|
Return argument @var{ARG} as XML object. @var{name}
|
|
must be a @code{method} or @code{signal} XML element. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-argument
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search" "GetHitData" "search")
|
|
|
|
@result{} (arg ((name . "search") (type . "s") (direction . "in")))
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-introspect-get-signature bus service path interface name &optional direction
|
|
Return signature of a @code{method} or @code{signal}, represented by
|
|
@var{name}, as string.
|
|
|
|
If @var{name} is a @code{method}, @var{direction} can be either
|
|
@samp{in} or @samp{out}. If @var{direction} is @code{nil}, @samp{in}
|
|
is assumed.
|
|
|
|
If @var{name} is a @code{signal}, and @var{direction} is
|
|
non-@code{nil}, @var{direction} must be @samp{out}. Example:
|
|
|
|
@lisp
|
|
(dbus-introspect-get-signature
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search" "GetHitData" "in")
|
|
|
|
@result{} "sauas"
|
|
|
|
(dbus-introspect-get-signature
|
|
:session "org.freedesktop.xesam.searcher"
|
|
"/org/freedesktop/xesam/searcher/main"
|
|
"org.freedesktop.xesam.Search" "HitsAdded")
|
|
|
|
@result{} "su"
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Type Conversion
|
|
@chapter Mapping Lisp types and D-Bus types.
|
|
@cindex type conversion
|
|
|
|
D-Bus method calls and signals accept usually several arguments as
|
|
parameters, either as input parameter, or as output parameter. Every
|
|
argument belongs to a D-Bus type.
|
|
|
|
Such arguments must be mapped between the value encoded as a D-Bus
|
|
type, and the corresponding type of Lisp objects. The mapping is
|
|
applied Lisp object @expansion{} D-Bus type for input parameters, and
|
|
D-Bus type @expansion{} Lisp object for output parameters.
|
|
|
|
|
|
@section Input parameters.
|
|
|
|
Input parameters for D-Bus methods and signals occur as arguments of a
|
|
Lisp function call. The following mapping to D-Bus types is
|
|
applied, when the corresponding D-Bus message is created:
|
|
|
|
@example
|
|
@multitable {negative integer} {@expansion{}} {DBUS_TYPE_BOOLEAN}
|
|
@item Lisp type @tab @tab D-Bus type
|
|
@item
|
|
@item @code{t} and @code{nil} @tab @expansion{} @tab DBUS_TYPE_BOOLEAN
|
|
@item natural number @tab @expansion{} @tab DBUS_TYPE_UINT32
|
|
@item negative integer @tab @expansion{} @tab DBUS_TYPE_INT32
|
|
@item float @tab @expansion{} @tab DBUS_TYPE_DOUBLE
|
|
@item string @tab @expansion{} @tab DBUS_TYPE_STRING
|
|
@item list @tab @expansion{} @tab DBUS_TYPE_ARRAY
|
|
@end multitable
|
|
@end example
|
|
|
|
Other Lisp objects, like symbols or hash tables, are not accepted as
|
|
input parameters.
|
|
|
|
If it is necessary to use another D-Bus type, a corresponding type
|
|
symbol can be prepended to the corresponding Lisp object. Basic D-Bus
|
|
types are represented by the type symbols @code{:byte},
|
|
@code{:boolean}, @code{:int16}, @code{:uint16}, @code{:int32},
|
|
@code{:uint32}, @code{:int64}, @code{:uint64}, @code{:double},
|
|
@code{:string}, @code{:object-path}, @code{:signature} and
|
|
@code{:unix-fd}.
|
|
|
|
@noindent
|
|
Example:
|
|
|
|
@lisp
|
|
(dbus-call-method @dots{} @var{NAT-NUMBER} @var{STRING})
|
|
@end lisp
|
|
|
|
is equivalent to
|
|
|
|
@lisp
|
|
(dbus-call-method @dots{} :uint32 @var{NAT-NUMBER} :string @var{STRING})
|
|
@end lisp
|
|
|
|
but different to
|
|
|
|
@lisp
|
|
(dbus-call-method @dots{} :int32 @var{NAT-NUMBER} :signature @var{STRING})
|
|
@end lisp
|
|
|
|
The value for a byte D-Bus type can be any integer in the range 0
|
|
through 255. If a character is used as argument, modifiers
|
|
represented outside this range are stripped of. For example,
|
|
@code{:byte ?x} is equal to @code{:byte ?\M-x}, but it is not equal to
|
|
@code{:byte ?\C-x} or @code{:byte ?\M-\C-x}.
|
|
|
|
Signed and unsigned integer D-Bus types expect a corresponding integer
|
|
value. If the value does not fit Emacs's integer range, it is also
|
|
possible to use an equivalent floating point number.
|
|
|
|
A D-Bus compound type is always represented as a list. The @sc{car}
|
|
of this list can be the type symbol @code{:array}, @code{:variant},
|
|
@code{:struct} or @code{:dict-entry}, which would result in a
|
|
corresponding D-Bus container. @code{:array} is optional, because
|
|
this is the default compound D-Bus type for a list.
|
|
|
|
The objects being elements of the list are checked according to the
|
|
D-Bus compound type rules.
|
|
|
|
@itemize
|
|
@item An array must contain only elements of the same D-Bus type. It
|
|
can be empty.
|
|
|
|
@item A variant must contain only one single element.
|
|
|
|
@item A dictionary entry must be element of an array, and it must
|
|
contain only a key-value pair of two elements, with a basic D-Bus type
|
|
key.
|
|
|
|
@item There is no restriction for structs.
|
|
@end itemize
|
|
|
|
If an empty array needs an element D-Bus type other than string, it
|
|
can contain exactly one element of D-Bus type @code{:signature}. The
|
|
value of this element (a string) is used as the signature of the
|
|
elements of this array. Example:
|
|
|
|
@lisp
|
|
(dbus-call-method
|
|
:session "org.freedesktop.Notifications"
|
|
"/org/freedesktop/Notifications"
|
|
"org.freedesktop.Notifications" "Notify"
|
|
"GNU Emacs" ;; Application name.
|
|
0 ;; No replacement of other notifications.
|
|
"" ;; No icon.
|
|
"Notification summary" ;; Summary.
|
|
(format ;; Body.
|
|
"This is a test notification, raised from\n%S" (emacs-version))
|
|
'(:array) ;; No actions (empty array of strings).
|
|
'(:array :signature "@{sv@}") ;; No hints
|
|
;; (empty array of dictionary entries).
|
|
:int32 -1) ;; Default timeout.
|
|
|
|
@result{} 3
|
|
@end lisp
|
|
|
|
@defun dbus-string-to-byte-array string
|
|
Sometimes, D-Bus methods require as input parameter an array of bytes,
|
|
instead of a string. If it is guaranteed, that @var{string} is an
|
|
UTF8 string, this function performs the conversion. Example:
|
|
|
|
@lisp
|
|
(dbus-string-to-byte-array "/etc/hosts")
|
|
|
|
@result{} (:array :byte 47 :byte 101 :byte 116 :byte 99 :byte 47
|
|
:byte 104 :byte 111 :byte 115 :byte 116 :byte 115)
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-escape-as-identifier string
|
|
Escape an arbitrary @var{string} so it follows the rules for a C
|
|
identifier. The escaped string can be used as object path component,
|
|
interface element component, bus name component or member name in
|
|
D-Bus.
|
|
|
|
The escaping consists of replacing all non-alphanumerics, and the
|
|
first character if it's a digit, with an underscore and two
|
|
lower-case hex digits. As a special case, "" is escaped to
|
|
"_". Example:
|
|
|
|
@lisp
|
|
(dbus-escape-as-identifier "0123abc_xyz\x01\xff")
|
|
|
|
@result{} "_30123abc_5fxyz_01_ff"
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@section Output parameters.
|
|
|
|
Output parameters of D-Bus methods and signals are mapped to Lisp
|
|
objects.
|
|
|
|
@example
|
|
@multitable {DBUS_TYPE_OBJECT_PATH} {@expansion{}} {natural number or float}
|
|
@item D-Bus type @tab @tab Lisp type
|
|
@item
|
|
@item DBUS_TYPE_BOOLEAN @tab @expansion{} @tab @code{t} or @code{nil}
|
|
@item DBUS_TYPE_BYTE @tab @expansion{} @tab natural number
|
|
@item DBUS_TYPE_UINT16 @tab @expansion{} @tab natural number
|
|
@item DBUS_TYPE_INT16 @tab @expansion{} @tab integer
|
|
@item DBUS_TYPE_UINT32 @tab @expansion{} @tab natural number or float
|
|
@item DBUS_TYPE_UNIX_FD @tab @expansion{} @tab natural number or float
|
|
@item DBUS_TYPE_INT32 @tab @expansion{} @tab integer or float
|
|
@item DBUS_TYPE_UINT64 @tab @expansion{} @tab natural number or float
|
|
@item DBUS_TYPE_INT64 @tab @expansion{} @tab integer or float
|
|
@item DBUS_TYPE_DOUBLE @tab @expansion{} @tab float
|
|
@item DBUS_TYPE_STRING @tab @expansion{} @tab string
|
|
@item DBUS_TYPE_OBJECT_PATH @tab @expansion{} @tab string
|
|
@item DBUS_TYPE_SIGNATURE @tab @expansion{} @tab string
|
|
@item DBUS_TYPE_ARRAY @tab @expansion{} @tab list
|
|
@item DBUS_TYPE_VARIANT @tab @expansion{} @tab list
|
|
@item DBUS_TYPE_STRUCT @tab @expansion{} @tab list
|
|
@item DBUS_TYPE_DICT_ENTRY @tab @expansion{} @tab list
|
|
@end multitable
|
|
@end example
|
|
|
|
A float object in case of @code{DBUS_TYPE_UINT32},
|
|
@code{DBUS_TYPE_INT32}, @code{DBUS_TYPE_UINT64},
|
|
@code{DBUS_TYPE_INT64} and @code{DBUS_TYPE_UNIX_FD} is returned, when
|
|
the C value exceeds the Emacs number size range.
|
|
|
|
The resulting list of the last 4 D-Bus compound types contains as
|
|
elements the elements of the D-Bus container, mapped according to the
|
|
same rules.
|
|
|
|
The signal @code{PropertyModified}, discussed as example in
|
|
@ref{Inspection}, would offer as Lisp data the following object
|
|
(@var{BOOL} stands here for either @code{nil} or @code{t}):
|
|
|
|
@lisp
|
|
(@var{INTEGER} ((@var{STRING} @var{BOOL} @var{BOOL}) (@var{STRING} @var{BOOL} @var{BOOL}) @dots{}))
|
|
@end lisp
|
|
|
|
@defun dbus-byte-array-to-string byte-array &optional multibyte
|
|
If a D-Bus method or signal returns an array of bytes, which are known
|
|
to represent an UTF8 string, this function converts @var{byte-array}
|
|
to the corresponding string. The string is unibyte encoded, unless
|
|
@var{multibyte} is non-@code{nil}. Example:
|
|
|
|
@lisp
|
|
(dbus-byte-array-to-string '(47 101 116 99 47 104 111 115 116 115))
|
|
|
|
@result{} "/etc/hosts"
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-unescape-from-identifier string
|
|
Retrieve the original string from the encoded @var{string} as unibyte
|
|
string. @var{string} must have been encoded with
|
|
@code{dbus-escape-as-identifier}. Example:
|
|
|
|
@lisp
|
|
(dbus-unescape-from-identifier "_30123abc_5fxyz_01_ff")
|
|
|
|
@result{} "0123abc_xyz\x01\xff"
|
|
@end lisp
|
|
|
|
If the original string used in @code{dbus-escape-as-identifier} is a
|
|
multibyte string, it cannot be expected that this function returns
|
|
that string:
|
|
|
|
@lisp
|
|
(string-equal
|
|
(dbus-unescape-from-identifier
|
|
(dbus-escape-as-identifier "Grüß Göttin"))
|
|
"Grüß Göttin")
|
|
|
|
@result{} nil
|
|
@end lisp
|
|
|
|
|
|
@end defun
|
|
|
|
|
|
@node Synchronous Methods
|
|
@chapter Calling methods in a blocking way.
|
|
@cindex method calls, synchronous
|
|
@cindex synchronous method calls
|
|
|
|
Methods can be called synchronously (@dfn{blocking}) or asynchronously
|
|
(@dfn{non-blocking}).
|
|
|
|
At D-Bus level, a method call consist of two messages: one message
|
|
which carries the input parameters to the object owning the method to
|
|
be called, and a reply message returning the resulting output
|
|
parameters from the object.
|
|
|
|
@defun dbus-call-method bus service path interface method &optional :timeout timeout &rest args
|
|
This function calls @var{method} on the D-Bus @var{bus}. @var{bus} is
|
|
either the symbol @code{:system} or the symbol @code{:session}.
|
|
|
|
@var{service} is the D-Bus service name to be used. @var{path} is the
|
|
D-Bus object path, @var{service} is registered at. @var{interface} is
|
|
an interface offered by @var{service}. It must provide @var{method}.
|
|
|
|
If the parameter @code{:timeout} is given, the following integer
|
|
@var{timeout} specifies the maximum number of milliseconds the method
|
|
call must return. The default value is 25,000. If the method call
|
|
doesn't return in time, a D-Bus error is raised (@pxref{Errors and
|
|
Events}).
|
|
|
|
All other arguments args are passed to @var{method} as arguments.
|
|
They are converted into D-Bus types as described in @ref{Type
|
|
Conversion}.
|
|
|
|
The function returns the resulting values of @var{method} as a list of
|
|
Lisp objects, according to the type conversion rules described in
|
|
@ref{Type Conversion}. Example:
|
|
|
|
@lisp
|
|
(dbus-call-method
|
|
:session "org.gnome.seahorse" "/org/gnome/seahorse/keys/openpgp"
|
|
"org.gnome.seahorse.Keys" "GetKeyField"
|
|
"openpgp:657984B8C7A966DD" "simple-name")
|
|
|
|
@result{} (t ("Philip R. Zimmermann"))
|
|
@end lisp
|
|
|
|
If the result of the method call is just one value, the converted Lisp
|
|
object is returned instead of a list containing this single Lisp
|
|
object. Example:
|
|
|
|
@lisp
|
|
(dbus-call-method
|
|
:system "org.freedesktop.Hal"
|
|
"/org/freedesktop/Hal/devices/computer"
|
|
"org.freedesktop.Hal.Device" "GetPropertyString"
|
|
"system.kernel.machine")
|
|
|
|
@result{} "i686"
|
|
@end lisp
|
|
|
|
With the @code{dbus-introspect} function it is possible to explore the
|
|
interfaces of @samp{org.freedesktop.Hal} service. It offers the
|
|
interfaces @samp{org.freedesktop.Hal.Manager} for the object at the
|
|
path @samp{/org/freedesktop/Hal/Manager} as well as the interface
|
|
@samp{org.freedesktop.Hal.Device} for all objects prefixed with the
|
|
path @samp{/org/freedesktop/Hal/devices}. With the methods
|
|
@samp{GetAllDevices} and @samp{GetAllProperties}, it is simple to
|
|
emulate the @code{lshal} command on GNU/Linux systems:
|
|
|
|
@lisp
|
|
(dolist (device
|
|
(dbus-call-method
|
|
:system "org.freedesktop.Hal"
|
|
"/org/freedesktop/Hal/Manager"
|
|
"org.freedesktop.Hal.Manager" "GetAllDevices"))
|
|
(message "\nudi = %s" device)
|
|
(dolist (properties
|
|
(dbus-call-method
|
|
:system "org.freedesktop.Hal" device
|
|
"org.freedesktop.Hal.Device" "GetAllProperties"))
|
|
(message " %s = %S"
|
|
(car properties) (or (caar (cdr properties)) ""))))
|
|
|
|
@print{} "udi = /org/freedesktop/Hal/devices/computer
|
|
info.addons = (\"hald-addon-acpi\")
|
|
info.bus = \"unknown\"
|
|
info.product = \"Computer\"
|
|
info.subsystem = \"unknown\"
|
|
info.udi = \"/org/freedesktop/Hal/devices/computer\"
|
|
linux.sysfs_path_device = \"(none)\"
|
|
power_management.acpi.linux.version = \"20051216\"
|
|
power_management.can_suspend_to_disk = t
|
|
power_management.can_suspend_to_ram = \"\"
|
|
power_management.type = \"acpi\"
|
|
smbios.bios.release_date = \"11/07/2001\"
|
|
system.chassis.manufacturer = \"COMPAL\"
|
|
system.chassis.type = \"Notebook\"
|
|
system.firmware.release_date = \"03/19/2005\"
|
|
@dots{}"
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Asynchronous Methods
|
|
@chapter Calling methods non-blocking.
|
|
@cindex method calls, asynchronous
|
|
@cindex asynchronous method calls
|
|
|
|
@defun dbus-call-method-asynchronously bus service path interface method handler &optional :timeout timeout &rest args
|
|
This function calls @var{method} on the D-Bus @var{bus}
|
|
asynchronously. @var{bus} is either the symbol @code{:system} or the
|
|
symbol @code{:session}.
|
|
|
|
@var{service} is the D-Bus service name to be used. @var{path} is the
|
|
D-Bus object path, @var{service} is registered at. @var{interface} is
|
|
an interface offered by @var{service}. It must provide @var{method}.
|
|
|
|
@var{handler} is a Lisp function, which is called when the
|
|
corresponding return message has arrived. If @var{handler} is
|
|
@code{nil}, no return message will be expected.
|
|
|
|
If the parameter @code{:timeout} is given, the following integer
|
|
@var{timeout} specifies the maximum number of milliseconds a reply
|
|
message must arrive. The default value is 25,000. If there is no
|
|
reply message in time, a D-Bus error is raised (@pxref{Errors and
|
|
Events}).
|
|
|
|
All other arguments args are passed to @var{method} as arguments.
|
|
They are converted into D-Bus types as described in @ref{Type
|
|
Conversion}.
|
|
|
|
If @var{handler} is a Lisp function, the function returns a key into
|
|
the hash table @code{dbus-registered-objects-table}. The
|
|
corresponding entry in the hash table is removed, when the return
|
|
message has been arrived, and @var{handler} is called. Example:
|
|
|
|
@lisp
|
|
(dbus-call-method-asynchronously
|
|
:system "org.freedesktop.Hal"
|
|
"/org/freedesktop/Hal/devices/computer"
|
|
"org.freedesktop.Hal.Device" "GetPropertyString" 'message
|
|
"system.kernel.machine")
|
|
|
|
@result{} (:serial :system 2)
|
|
|
|
@print{} i686
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Receiving Method Calls
|
|
@chapter Offering own methods.
|
|
@cindex method calls, returning
|
|
@cindex returning method calls
|
|
|
|
In order to register methods on the D-Bus, Emacs has to request a well
|
|
known name on the D-Bus under which it will be available for other
|
|
clients. Names on the D-Bus can be registered and unregistered using
|
|
the following functions:
|
|
|
|
@defun dbus-register-service bus service &rest flags
|
|
Register the known name @var{service} on D-Bus @var{bus}.
|
|
|
|
@var{bus} is either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
|
|
@var{service} is the service name to be registered on the D-Bus. It
|
|
must be a known name.
|
|
|
|
@var{flags} is a subset of the following keywords:
|
|
|
|
@itemize
|
|
@item @code{:allow-replacement}: Allow another service to become the primary
|
|
owner if requested.
|
|
|
|
@item @code{:replace-existing}: Request to replace the current primary owner.
|
|
|
|
@item @code{:do-not-queue}: If we can not become the primary owner do not
|
|
place us in the queue.
|
|
@end itemize
|
|
|
|
One of the following keywords is returned:
|
|
|
|
@itemize
|
|
|
|
@item @code{:primary-owner}: We have become the primary owner of the name
|
|
@var{service}.
|
|
|
|
@item @code{:in-queue}: We could not become the primary owner and
|
|
have been placed in the queue.
|
|
|
|
@item @code{:exists}: We already are in the queue.
|
|
|
|
@item @code{:already-owner}: We already are the primary
|
|
owner.
|
|
@end itemize
|
|
@end defun
|
|
|
|
@defun dbus-unregister-service bus service
|
|
Unregister all objects from D-Bus @var{bus}, registered by Emacs for
|
|
@var{service}.
|
|
|
|
@var{bus} is either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
|
|
@var{service} is the D-Bus service name of the D-Bus. It must be a
|
|
known name. Emacs releases its association to @var{service} from
|
|
D-Bus.
|
|
|
|
One of the following keywords is returned:
|
|
|
|
@itemize
|
|
@item @code{:released}: We successfully released the name @var{service}.
|
|
@item @code{:non-existent}: The name @var{service} does not exist on the bus.
|
|
@item @code{:not-owner}: We are not an owner of the name @var{service}.
|
|
@end itemize
|
|
@end defun
|
|
|
|
When a name has been chosen, Emacs can offer own methods, which can be
|
|
called by other applications. These methods could be an
|
|
implementation of an interface of a well known service, like
|
|
@samp{org.freedesktop.TextEditor}.
|
|
|
|
It could be also an implementation of an own interface. In this case,
|
|
the service name must be @samp{org.gnu.Emacs}. The object path shall
|
|
begin with @samp{/org/gnu/Emacs/@strong{Application}}, and the
|
|
interface name shall be @code{org.gnu.Emacs.@strong{Application}}.
|
|
@samp{@strong{Application}} is the name of the application which
|
|
provides the interface.
|
|
|
|
@deffn Constant dbus-service-emacs
|
|
The well known service name @samp{org.gnu.Emacs} of Emacs.
|
|
@end deffn
|
|
|
|
@deffn Constant dbus-path-emacs
|
|
The object path namespace @samp{/org/gnu/Emacs} used by Emacs.
|
|
@end deffn
|
|
|
|
@deffn Constant dbus-interface-emacs
|
|
The interface namespace @code{org.gnu.Emacs} used by Emacs.
|
|
@end deffn
|
|
|
|
@defun dbus-register-method bus service path interface method handler dont-register-service
|
|
With this function, an application registers @var{method} on the D-Bus
|
|
@var{bus}.
|
|
|
|
@var{bus} is either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
|
|
@var{service} is the D-Bus service name of the D-Bus object
|
|
@var{method} is registered for. It must be a known name (See
|
|
discussion of @var{dont-register-service} below).
|
|
|
|
@var{path} is the D-Bus object path @var{service} is registered (See
|
|
discussion of @var{dont-register-service} below).
|
|
|
|
@var{interface} is the interface offered by @var{service}. It must
|
|
provide @var{method}.
|
|
|
|
@var{handler} is a Lisp function to be called when a @var{method} call
|
|
is received. It must accept as arguments the input arguments of
|
|
@var{method}. @var{handler} should return a list, whose elements are
|
|
to be used as arguments for the reply message of @var{method}. This
|
|
list can be composed like the input parameters in @ref{Type
|
|
Conversion}.
|
|
|
|
If @var{handler} wants to return just one Lisp object and it is not a
|
|
cons cell, @var{handler} can return this object directly, instead of
|
|
returning a list containing the object.
|
|
|
|
In case @var{handler} shall return a reply message with an empty
|
|
argument list, @var{handler} must return the symbol @code{:ignore}.
|
|
|
|
When @var{dont-register-service} is non-@code{nil}, the known name
|
|
@var{service} is not registered. This means that other D-Bus clients
|
|
have no way of noticing the newly registered method. When interfaces
|
|
are constructed incrementally by adding single methods or properties
|
|
at a time, @var{dont-register-service} can be used to prevent other
|
|
clients from discovering the still incomplete interface.
|
|
|
|
The default D-Bus timeout when waiting for a message reply is 25
|
|
seconds. This value could be even smaller, depending on the calling
|
|
client. Therefore, @var{handler} shall not last longer than
|
|
absolutely necessary.
|
|
|
|
@code{dbus-register-method} returns a Lisp object, which can be used
|
|
as argument in @code{dbus-unregister-object} for removing the
|
|
registration for @var{method}. Example:
|
|
|
|
@lisp
|
|
(defun my-dbus-method-handler (filename)
|
|
(let (result)
|
|
(if (find-file filename)
|
|
(setq result '(:boolean t))
|
|
(setq result '(:boolean nil)))
|
|
result))
|
|
|
|
@result{} my-dbus-method-handler
|
|
|
|
(dbus-register-method
|
|
:session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"
|
|
"org.freedesktop.TextEditor" "OpenFile"
|
|
'my-dbus-method-handler)
|
|
|
|
@result{} ((:method :session "org.freedesktop.TextEditor" "OpenFile")
|
|
("org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"
|
|
my-dbus-method-handler))
|
|
@end lisp
|
|
|
|
If you invoke the method @samp{org.freedesktop.TextEditor.OpenFile}
|
|
from another D-Bus application with a filename as parameter, the file
|
|
is opened in Emacs, and the method returns either @var{true} or
|
|
@var{false}, indicating the success of the method. As test tool one
|
|
could use the command line tool @code{dbus-send} in a shell:
|
|
|
|
@example
|
|
# dbus-send --session --print-reply \
|
|
--dest="org.freedesktop.TextEditor" \
|
|
"/org/freedesktop/TextEditor" \
|
|
"org.freedesktop.TextEditor.OpenFile" string:"/etc/hosts"
|
|
|
|
@print{} method return sender=:1.22 -> dest=:1.23 reply_serial=2
|
|
boolean true
|
|
@end example
|
|
|
|
You can indicate an error by raising the Emacs signal
|
|
@code{dbus-error}. The handler above could be changed like this:
|
|
|
|
@lisp
|
|
(defun my-dbus-method-handler (&rest args)
|
|
(unless (and (= (length args) 1) (stringp (car args)))
|
|
(signal 'dbus-error (list (format "Wrong argument list: %S" args))))
|
|
(condition-case err
|
|
(find-file (car args))
|
|
(error (signal 'dbus-error (cdr err))))
|
|
t)
|
|
|
|
@result{} my-dbus-method-handler
|
|
@end lisp
|
|
|
|
The test runs then
|
|
|
|
@example
|
|
# dbus-send --session --print-reply \
|
|
--dest="org.freedesktop.TextEditor" \
|
|
"/org/freedesktop/TextEditor" \
|
|
"org.freedesktop.TextEditor.OpenFile" \
|
|
string:"/etc/hosts" string:"/etc/passwd"
|
|
|
|
@print{} Error org.freedesktop.DBus.Error.Failed:
|
|
Wrong argument list: ("/etc/hosts" "/etc/passwd")
|
|
@end example
|
|
@end defun
|
|
|
|
@defun dbus-register-property bus service path interface property access value &optional emits-signal dont-register-service
|
|
With this function, an application declares a @var{property} on the D-Bus
|
|
@var{bus}.
|
|
|
|
@var{bus} is either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
|
|
@var{service} is the D-Bus service name of the D-Bus. It must be a
|
|
known name.
|
|
|
|
@var{path} is the D-Bus object path @var{service} is registered (See
|
|
discussion of @var{dont-register-service} below).
|
|
|
|
@var{interface} is the name of the interface used at @var{path},
|
|
@var{property} is the name of the property of @var{interface}.
|
|
|
|
@var{access} indicates, whether the property can be changed by other
|
|
services via D-Bus. It must be either the symbol @code{:read} or
|
|
@code{:readwrite}. @var{value} is the initial value of the property,
|
|
it can be of any valid type (see @code{dbus-call-method} for details).
|
|
|
|
If @var{property} already exists on @var{path}, it will be
|
|
overwritten. For properties with access type @code{:read} this is the
|
|
only way to change their values. Properties with access type
|
|
@code{:readwrite} can be changed by @code{dbus-set-property}.
|
|
|
|
The interface @samp{org.freedesktop.DBus.Properties} is added to
|
|
@var{path}, including a default handler for the @samp{Get},
|
|
@samp{GetAll} and @samp{Set} methods of this interface. When
|
|
@var{emits-signal} is non-@code{nil}, the signal
|
|
@samp{PropertiesChanged} is sent when the property is changed by
|
|
@code{dbus-set-property}.
|
|
|
|
When @var{dont-register-service} is non-@code{nil}, the known name
|
|
@var{service} is not registered. This means that other D-Bus clients
|
|
have no way of noticing the newly registered method. When interfaces
|
|
are constructed incrementally by adding single methods or properties
|
|
at a time, @var{dont-register-service} can be used to prevent other
|
|
clients from discovering the still incomplete interface.
|
|
|
|
@noindent Example:
|
|
|
|
@lisp
|
|
(dbus-register-property
|
|
:session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"
|
|
"org.freedesktop.TextEditor" "name" :read "GNU Emacs")
|
|
|
|
@result{} ((:property :session "org.freedesktop.TextEditor" "name")
|
|
("org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"))
|
|
|
|
(dbus-register-property
|
|
:session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"
|
|
"org.freedesktop.TextEditor" "version" :readwrite emacs-version t)
|
|
|
|
@result{} ((:property :session "org.freedesktop.TextEditor" "version")
|
|
("org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"))
|
|
@end lisp
|
|
|
|
Other D-Bus applications can read the property via the default methods
|
|
@samp{org.freedesktop.DBus.Properties.Get} and
|
|
@samp{org.freedesktop.DBus.Properties.GetAll}. Testing is also
|
|
possible via the command line tool @code{dbus-send} in a shell:
|
|
|
|
@example
|
|
# dbus-send --session --print-reply \
|
|
--dest="org.freedesktop.TextEditor" \
|
|
"/org/freedesktop/TextEditor" \
|
|
"org.freedesktop.DBus.Properties.GetAll" \
|
|
string:"org.freedesktop.TextEditor"
|
|
|
|
@print{} method return sender=:1.22 -> dest=:1.23 reply_serial=3
|
|
array [
|
|
dict entry(
|
|
string "name"
|
|
variant string "GNU Emacs"
|
|
)
|
|
dict entry(
|
|
string "version"
|
|
variant string "23.1.50.5"
|
|
)
|
|
]
|
|
@end example
|
|
|
|
It is also possible, to apply the @code{dbus-get-property},
|
|
@code{dbus-get-all-properties} and @code{dbus-set-property} functions
|
|
(@pxref{Properties and Annotations}).
|
|
|
|
@lisp
|
|
(dbus-set-property
|
|
:session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"
|
|
"org.freedesktop.TextEditor" "version" "23.1.50")
|
|
|
|
@result{} "23.1.50"
|
|
|
|
(dbus-get-property
|
|
:session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor"
|
|
"org.freedesktop.TextEditor" "version")
|
|
|
|
@result{} "23.1.50"
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-unregister-object object
|
|
Unregister @var{object} from the D-Bus. @var{object} must be the
|
|
result of a preceding @code{dbus-register-method},
|
|
@code{dbus-register-property} or @code{dbus-register-signal} call
|
|
(@pxref{Signals}). It returns @code{t} if @var{object} has been
|
|
unregistered, @code{nil} otherwise.
|
|
|
|
When @var{object} identifies the last method or property, which is
|
|
registered for the respective service, Emacs releases its association
|
|
to the service from D-Bus.
|
|
@end defun
|
|
|
|
|
|
@node Signals
|
|
@chapter Sending and receiving signals.
|
|
@cindex signals
|
|
|
|
Signals are one way messages. They carry input parameters, which are
|
|
received by all objects which have registered for such a signal.
|
|
|
|
@defun dbus-send-signal bus service path interface signal &rest args
|
|
This function is similar to @code{dbus-call-method}. The difference
|
|
is, that there are no returning output parameters.
|
|
|
|
The function emits @var{signal} on the D-Bus @var{bus}. @var{bus} is
|
|
either the symbol @code{:system} or the symbol @code{:session}. It
|
|
doesn't matter whether another object has registered for @var{signal}.
|
|
|
|
Signals can be unicast or broadcast messages. For broadcast messages,
|
|
@var{service} must be @code{nil}. Otherwise, @var{service} is the
|
|
D-Bus service name the signal is sent to as unicast
|
|
message.@footnote{For backward compatibility, a broadcast message is
|
|
also emitted if @var{service} is the known or unique name Emacs is
|
|
registered at D-Bus @var{bus}.} @var{path} is the D-Bus object path
|
|
@var{signal} is sent from. @var{interface} is an interface available
|
|
at @var{path}. It must provide @var{signal}.
|
|
|
|
All other arguments args are passed to @var{signal} as arguments.
|
|
They are converted into D-Bus types as described in @ref{Type
|
|
Conversion}. Example:
|
|
|
|
@lisp
|
|
(dbus-send-signal
|
|
:session nil dbus-path-emacs
|
|
(concat dbus-interface-emacs ".FileManager") "FileModified"
|
|
"/home/albinus/.emacs")
|
|
@end lisp
|
|
@end defun
|
|
|
|
@defun dbus-register-signal bus service path interface signal handler &rest args
|
|
With this function, an application registers for a signal on the D-Bus
|
|
@var{bus}.
|
|
|
|
@var{bus} is either the symbol @code{:system} or the symbol
|
|
@code{:session}.
|
|
|
|
@var{service} is the D-Bus service name used by the sending D-Bus
|
|
object. It can be either a known name or the unique name of the D-Bus
|
|
object sending the signal. A known name will be mapped onto the
|
|
unique name of the object, owning @var{service} at registration time.
|
|
When the corresponding D-Bus object disappears, signals won't be
|
|
received any longer.
|
|
|
|
@var{path} is the corresponding D-Bus object path, @var{service} is
|
|
registered at. @var{interface} is an interface offered by
|
|
@var{service}. It must provide @var{signal}.
|
|
|
|
@var{service}, @var{path}, @var{interface} and @var{signal} can be
|
|
@code{nil}. This is interpreted as a wildcard for the respective
|
|
argument.
|
|
|
|
@var{handler} is a Lisp function to be called when the @var{signal} is
|
|
received. It must accept as arguments the output parameters
|
|
@var{signal} is sending.
|
|
|
|
The remaining arguments @var{args} can be keywords or keyword string
|
|
pairs.@footnote{For backward compatibility, the arguments @var{args}
|
|
can also be just strings. They stand for the respective arguments of
|
|
@var{signal} in their order, and are used for filtering as well. A
|
|
@code{nil} argument might be used to preserve the order.} The meaning
|
|
is as follows:
|
|
|
|
@itemize
|
|
@item @code{:argN} @var{string}:@*
|
|
@code{:pathN} @var{string}:@*
|
|
This stands for the Nth argument of the signal. @code{:pathN}
|
|
arguments can be used for object path wildcard matches as specified by
|
|
D-Bus, while an @code{:argN} argument requires an exact match.
|
|
|
|
@item @code{:arg-namespace} @var{string}:@*
|
|
Register for the signals, which first argument defines the service or
|
|
interface namespace @var{string}.
|
|
|
|
@item @code{:path-namespace} @var{string}:@*
|
|
Register for the object path namespace @var{string}. All signals sent
|
|
from an object path, which has @var{string} as the preceding string,
|
|
are matched. This requires @var{path} to be @code{nil}.
|
|
|
|
@item @code{:eavesdrop}:@*
|
|
Register for unicast signals which are not directed to the D-Bus
|
|
object Emacs is registered at D-Bus BUS, if the security policy of BUS
|
|
allows this. Otherwise, this argument is ignored.
|
|
@end itemize
|
|
|
|
@code{dbus-register-signal} returns a Lisp object, which can be used
|
|
as argument in @code{dbus-unregister-object} for removing the
|
|
registration for @var{signal}. Example:
|
|
|
|
@lisp
|
|
(defun my-dbus-signal-handler (device)
|
|
(message "Device %s added" device))
|
|
|
|
@result{} my-dbus-signal-handler
|
|
|
|
(dbus-register-signal
|
|
:system "org.freedesktop.Hal" "/org/freedesktop/Hal/Manager"
|
|
"org.freedesktop.Hal.Manager" "DeviceAdded"
|
|
'my-dbus-signal-handler)
|
|
|
|
@result{} ((:signal :system "org.freedesktop.Hal.Manager" "DeviceAdded")
|
|
("org.freedesktop.Hal" "/org/freedesktop/Hal/Manager"
|
|
my-signal-handler))
|
|
@end lisp
|
|
|
|
As we know from the introspection data of interface
|
|
@samp{org.freedesktop.Hal.Manager}, the signal @samp{DeviceAdded}
|
|
provides one single parameter, which is mapped into a Lisp string.
|
|
The callback function @code{my-dbus-signal-handler} must define one
|
|
single string argument therefore. Plugging an USB device to your
|
|
machine, when registered for signal @samp{DeviceAdded}, will show you
|
|
which objects the GNU/Linux @code{hal} daemon adds.
|
|
|
|
Some of the match rules have been added to a later version of D-Bus.
|
|
In order to test the availability of such features, you could register
|
|
for a dummy signal, and check the result:
|
|
|
|
@lisp
|
|
(dbus-ignore-errors
|
|
(dbus-register-signal
|
|
:system nil nil nil nil 'ignore :path-namespace "/invalid/path"))
|
|
|
|
@result{} nil
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Alternative Buses
|
|
@chapter Alternative buses and environments.
|
|
@cindex bus names
|
|
@cindex UNIX domain socket
|
|
@cindex TCP/IP socket
|
|
|
|
Until now, we have spoken about the system and the session buses,
|
|
which are the default buses to be connected to. However, it is
|
|
possible to connect to any bus, from which the address is known. This
|
|
is a UNIX domain or TCP/IP socket. Everywhere, where a @var{bus} is
|
|
mentioned as argument of a function (the symbol @code{:system} or the
|
|
symbol @code{:session}), this address can be used instead. The
|
|
connection to this bus must be initialized first.
|
|
|
|
@defun dbus-init-bus bus &optional private
|
|
Establish the connection to D-Bus @var{bus}.
|
|
|
|
@var{bus} can be either the symbol @code{:system} or the symbol
|
|
@code{:session}, or it can be a string denoting the address of the
|
|
corresponding bus. For the system and session buses, this function
|
|
is called when loading @file{dbus.el}, there is no need to call it
|
|
again.
|
|
|
|
The function returns a number, which counts the connections this Emacs
|
|
session has established to the @var{bus} under the same unique name
|
|
(see @code{dbus-get-unique-name}). It depends on the libraries Emacs
|
|
is linked with, and on the environment Emacs is running. For example,
|
|
if Emacs is linked with the gtk toolkit, and it runs in a GTK-aware
|
|
environment like Gnome, another connection might already be
|
|
established.
|
|
|
|
When @var{private} is non-@code{nil}, a new connection is established
|
|
instead of reusing an existing one. It results in a new unique name
|
|
at the bus. This can be used, if it is necessary to distinguish from
|
|
another connection used in the same Emacs process, like the one
|
|
established by GTK+. It should be used with care for at least the
|
|
@code{:system} and @code{:session} buses, because other Emacs Lisp
|
|
packages might already use this connection to those buses.
|
|
|
|
Example: You initialize a connection to the AT-SPI bus on your host:
|
|
|
|
@lisp
|
|
(setq my-bus
|
|
(dbus-call-method
|
|
:session "org.a11y.Bus" "/org/a11y/bus"
|
|
"org.a11y.Bus" "GetAddress"))
|
|
|
|
@result{} "unix:abstract=/tmp/dbus-2yzWHOCdSD,guid=a490dd26625870ca1298b6e10000fd7f"
|
|
|
|
;; If Emacs is built with gtk support, and you run in a GTK enabled
|
|
;; environment (like a GNOME session), the initialization reuses the
|
|
;; connection established by GTK's atk bindings.
|
|
(dbus-init-bus my-bus)
|
|
|
|
@result{} 2
|
|
|
|
(dbus-get-unique-name my-bus)
|
|
|
|
@result{} ":1.19"
|
|
|
|
;; Open a new connection to the same bus. This obsoletes the
|
|
;; previous one.
|
|
(dbus-init-bus my-bus 'private)
|
|
|
|
@result{} 1
|
|
|
|
(dbus-get-unique-name my-bus)
|
|
|
|
@result{} ":1.20"
|
|
@end lisp
|
|
|
|
D-Bus addresses can specify different transport. A possible address
|
|
could be based on TCP/IP sockets, see next example. However, it
|
|
depends on the bus daemon configuration, which transport is supported.
|
|
@end defun
|
|
|
|
@defun dbus-setenv bus variable value
|
|
Set the value of the @var{bus} environment variable @var{variable} to
|
|
@var{value}.
|
|
|
|
@var{bus} is either a Lisp symbol, @code{:system} or @code{:session},
|
|
or a string denoting the bus address. Both @var{variable} and
|
|
@var{value} should be strings.
|
|
|
|
Normally, services inherit the environment of the bus daemon. This
|
|
function adds to or modifies that environment when activating services.
|
|
|
|
Some bus instances, such as @code{:system}, may disable setting the
|
|
environment. In such cases, or if this feature is not available in
|
|
older D-Bus versions, a @code{dbus-error} error is raised.
|
|
|
|
As an example, it might be desirable to start X11 enabled services on
|
|
a remote host's bus on the same X11 server the local Emacs is
|
|
running. This could be achieved by
|
|
|
|
@lisp
|
|
(setq my-bus "unix:host=example.gnu.org,port=4711")
|
|
|
|
@result{} "unix:host=example.gnu.org,port=4711"
|
|
|
|
(dbus-init-bus my-bus)
|
|
|
|
@result{} 1
|
|
|
|
(dbus-setenv my-bus "DISPLAY" (getenv "DISPLAY"))
|
|
|
|
@result{} nil
|
|
@end lisp
|
|
@end defun
|
|
|
|
|
|
@node Errors and Events
|
|
@chapter Errors and events.
|
|
@cindex debugging
|
|
@cindex errors
|
|
@cindex events
|
|
|
|
The internal actions can be traced by running in a debug mode.
|
|
|
|
@defvar dbus-debug
|
|
If this variable is non-@code{nil}, D-Bus specific debug messages are raised.
|
|
@end defvar
|
|
|
|
Input parameters of @code{dbus-call-method},
|
|
@code{dbus-call-method-asynchronously}, @code{dbus-send-signal},
|
|
@code{dbus-register-method}, @code{dbus-register-property} and
|
|
@code{dbus-register-signal} are checked for correct D-Bus types. If
|
|
there is a type mismatch, the Lisp error @code{wrong-type-argument}
|
|
@code{D-Bus ARG} is raised.
|
|
|
|
All errors raised by D-Bus are signaled with the error symbol
|
|
@code{dbus-error}. If possible, error messages from D-Bus are
|
|
appended to the @code{dbus-error}.
|
|
|
|
@defspec dbus-ignore-errors forms@dots{}
|
|
This executes @var{forms} exactly like a @code{progn}, except that
|
|
@code{dbus-error} errors are ignored during the @var{forms}. These
|
|
errors can be made visible when @code{dbus-debug} is set to @code{t}.
|
|
@end defspec
|
|
|
|
Incoming D-Bus messages are handled as Emacs events, see @pxref{Misc
|
|
Events, , , elisp}. They are retrieved only, when Emacs runs in
|
|
interactive mode. The generated event has this form:
|
|
|
|
@lisp
|
|
(dbus-event @var{bus} @var{type} @var{serial} @var{service} @var{path} @var{interface} @var{member} @var{handler}
|
|
&rest @var{args})
|
|
@end lisp
|
|
|
|
@var{bus} identifies the D-Bus the message is coming from. It is
|
|
either the symbol @code{:system} or the symbol @code{:session}.
|
|
|
|
@var{type} is the D-Bus message type which has caused the event. It
|
|
can be @code{dbus-message-type-invalid},
|
|
@code{dbus-message-type-method-call},
|
|
@code{dbus-message-type-method-return},
|
|
@code{dbus-message-type-error}, or @code{dbus-message-type-signal}.
|
|
@var{serial} is the serial number of the received D-Bus message.
|
|
|
|
@var{service} and @var{path} are the unique name and the object path
|
|
of the D-Bus object emitting the message. @var{interface} and
|
|
@var{member} denote the message which has been sent.
|
|
|
|
@var{handler} is the callback function which has been registered for
|
|
this message (see @pxref{Signals}). When a @code{dbus-event} event
|
|
arrives, @var{handler} is called with @var{args} as arguments.
|
|
|
|
In order to inspect the @code{dbus-event} data, you could extend the
|
|
definition of the callback function in @ref{Signals}:
|
|
|
|
@lisp
|
|
(defun my-dbus-signal-handler (&rest args)
|
|
(message "my-dbus-signal-handler: %S" last-input-event))
|
|
@end lisp
|
|
|
|
There exist convenience functions which could be called inside a
|
|
callback function in order to retrieve the information from the event.
|
|
|
|
@defun dbus-event-bus-name event
|
|
Returns the bus name @var{event} is coming from.
|
|
The result is either the symbol @code{:system} or the symbol @code{:session}.
|
|
@end defun
|
|
|
|
@defun dbus-event-message-type event
|
|
Returns the message type of the corresponding D-Bus message. The
|
|
result is a natural number.
|
|
@end defun
|
|
|
|
@defun dbus-event-serial-number event
|
|
Returns the serial number of the corresponding D-Bus message.
|
|
The result is a natural number.
|
|
@end defun
|
|
|
|
@defun dbus-event-service-name event
|
|
Returns the unique name of the D-Bus object @var{event} is coming from.
|
|
@end defun
|
|
|
|
@defun dbus-event-path-name event
|
|
Returns the object path of the D-Bus object @var{event} is coming from.
|
|
@end defun
|
|
|
|
@defun dbus-event-interface-name event
|
|
Returns the interface name of the D-Bus object @var{event} is coming from.
|
|
@end defun
|
|
|
|
@defun dbus-event-member-name event
|
|
Returns the member name of the D-Bus object @var{event} is coming
|
|
from. It is either a signal name or a method name.
|
|
@end defun
|
|
|
|
D-Bus errors are not propagated during event handling, because it is
|
|
usually not desired. D-Bus errors in events can be made visible by
|
|
setting the variable @code{dbus-debug} to @code{t}. They can also be
|
|
handled by a hook function.
|
|
|
|
@defvar dbus-event-error-functions
|
|
This hook variable keeps a list of functions, which are called when a
|
|
D-Bus error happens in the event handler. Every function must accept
|
|
two arguments, the event and the error variable caught in
|
|
@code{condition-case} by @code{dbus-error}.
|
|
|
|
Such functions can be used the adapt the error signal to be raised.
|
|
Example:
|
|
|
|
@lisp
|
|
(defun my-dbus-event-error-handler (event error)
|
|
(when (string-equal (concat dbus-interface-emacs ".FileManager")
|
|
(dbus-event-interface-name event))
|
|
(message "my-dbus-event-error-handler: %S %S" event error)
|
|
(signal 'file-error (cdr error))))
|
|
|
|
(add-hook 'dbus-event-error-functions 'my-dbus-event-error-handler)
|
|
@end lisp
|
|
@end defvar
|
|
|
|
Hook functions shall take into account, that there might be other
|
|
D-Bus applications running. Therefore, they shall check carefully,
|
|
whether a given D-Bus error is related to them.
|
|
|
|
|
|
@node Index
|
|
@unnumbered Index
|
|
|
|
@printindex cp
|
|
|
|
|
|
@node GNU Free Documentation License
|
|
@appendix GNU Free Documentation License
|
|
@include doclicense.texi
|
|
|
|
@bye
|