# D_Bus/Ada

The D_Bus/Ada library provides an Ada binding to the D-Bus message bus used for inter-process communication on most modern Linux desktop systems.

## Licence

    Copyright (C) 2011-2024 Reto Buerki <reet@codelabs.ch>. Free use of this
    software is granted under the terms of the GNAT Modified General Public License
    (GMGPL).

## Download

### Release version

The current release version of D_Bus/Ada is available at https://www.codelabs.ch/download/.

### Verify a Release

To verify the integrity and authenticity of the distribution tarball type the following commands:

    $ wget -q https://www.codelabs.ch/keys/DBF6D7E1095FD0D9.asc -O - | gpg --import
    $ gpg --verify libdbusada-{version}.tar.bz2.sig

The key fingerprint of the public key (0xDBF6D7E1095FD0D9) is:

    Key fingerprint = 298F 4B32 C3C4 1D88 5949  86F3 DBF6 D7E1 095F D0D9

### Development version

The current development version of D_Bus/Ada is available through its git repository:

    $ git clone https://git.codelabs.ch/dbus-ada.git

A browsable version of the repository is available here: https://git.codelabs.ch/?p=dbus-ada.git.

## Build

To compile D_Bus/Ada on your system, you need to have the following software installed:

- GNAT compiler: https://www.gnu.org/software/gnat

- Ahven (Test-Framework): http://ahven.stronglytyped.org

- D-Bus development files and libraries https://www.freedesktop.org/wiki/Software/dbus

- Glib with D-Bus support

## Testing

Before you install D_Bus/Ada on your system, you might want to test the library and verify that everything works as expected. D_Bus/Ada contains an unit test suite which can be run by entering the following command:

    $ make tests

## Installation

To install D_Bus/Ada on your system, type the following:

    $ make PREFIX=/usr/local install

If no `PREFIX` is specified, `$(HOME)/libraries` is used as install destination.

## Examples

D_Bus/Ada provides example code to demonstrate the usage of the D_Bus/Ada API. To build all examples type the following:

    $ make examples

You can start an example application like so: `obj/examples/list_names`.

The following code connects to the D-Bus session bus, calls the remote `org.freedesktop.DBus.ListNames` method and prints all the results:

    --
    --  D_Bus/Ada - An Ada binding to D-Bus
    --
    --  Copyright (C) 2011, 2012  Reto Buerki <reet@codelabs.ch>
    --
    --  This program is free software; you can redistribute it and/or
    --  modify it under the terms of the GNU General Public License
    --  as published by the Free Software Foundation; either version 2
    --  of the License, or (at your option) any later version.
    --
    --  This program 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 General Public License for more details.
    --
    --  You should have received a copy of the GNU General Public License
    --  along with this program; if not, write to the Free Software
    --  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
    --  USA.
    --
    --  As a special exception, if other files instantiate generics from this
    --  unit,  or  you  link  this  unit  with  other  files  to  produce  an
    --  executable   this  unit  does  not  by  itself  cause  the  resulting
    --  executable to  be  covered by the  GNU General  Public License.  This
    --  exception does  not  however  invalidate  any  other reasons why  the
    --  executable file might be covered by the GNU Public License.
    --

    with Ada.Text_IO;

    with D_Bus.Types;
    with D_Bus.Arguments.Basic;
    with D_Bus.Arguments.Containers;
    with D_Bus.Connection;

    pragma Unreferenced (D_Bus.Arguments.Basic);
    pragma Unreferenced (D_Bus.Arguments.Containers);

    procedure List_Names
    is
       use D_Bus;
       use type D_Bus.Types.Obj_Path;

       --  Connect to the D-Bus session bus

       Conn   : constant Connection.Connection_Type := Connection.Connect;
       Result : Arguments.Argument_List_Type;

       procedure Print (Argument : Arguments.Argument_Type'Class);
       --  Print out an argument.

       procedure Print (Argument : Arguments.Argument_Type'Class)
       is
       begin
          Ada.Text_IO.Set_Col (To => 1);
          Ada.Text_IO.Put ("(" & Argument.Get_Code'Img & " )");
          Ada.Text_IO.Set_Col (To => 10);
          Ada.Text_IO.Put_Line (Argument.To_String);
       end Print;

    begin

       --  Request a name on the bus

       Connection.Request_Name
         (Connection => Conn,
          Name       => "dbus.ada.caller");

       --  Call a method on a remote object

       Result := Connection.Call_Blocking
         (Connection  => Conn,
          Destination => "org.freedesktop.DBus",
          Path        => +"/",
          Iface       => "org.freedesktop.DBus",
          Method      => "ListNames");
       Ada.Text_IO.Put_Line ("Method called successfully:");

       Arguments.Iterate (List    => Result,
                          Process => Print'Access);
    end List_Names;