=====
Usage
=====

SimpleDBus should work on any Linux environment supporting DBus.
Please follow the instructions below to build and run SimpleDBus in your specific environment.

System Requirements
===================

When building SimpleDBus from source, you will need some dependencies based on your
current operating system.

General Requirements
--------------------

   - `CMake`_ (Version 3.21 or higher)

Linux
-----

APT-based Distros
~~~~~~~~~~~~~~~~~

   - `libdbus-1-dev` (install via ``sudo apt install libdbus-1-dev``)

RPM-based Distros
~~~~~~~~~~~~~~~~~

   - `dbus-devel`
      - On Fedora, install via ``sudo dnf install dbus-devel``
      - On CentOS, install via ``sudo yum install dbus-devel``


Building and Installing the Library (Source)
============================================

Compiling the library is done using `CMake`_ and relies heavily on plenty of CMake
functionality. It is strongly suggested that you get familiarized with CMake before
blindly following the instructions below.


Building SimpleDBus
-------------------

You can use the following commands to build SimpleDBus: ::

   cmake -H <path-to-simpledbus> -B build_simpledbus
   cmake --build build_simpledbus -j7

Note that if you want to modify the build configuration, you can do so by passing
additional arguments to the ``cmake`` command. For example, to build a shared library
set the ``BUILD_SHARED_LIBS`` CMake variable to ``TRUE`` ::

   cmake -H <path-to-simpledbus> -B build_simpledbus -DBUILD_SHARED_LIBS=TRUE

To modify the log level, set the ``SIMPLEDBUS_LOG_LEVEL`` CMake variable to one of the
following values: ``VERBOSE``, ``DEBUG``, ``INFO``, ``WARN``, ``ERROR``, ``FATAL`` ::

   cmake -H <path-to-simpledbus> -B build_simpledbus -DSIMPLEDBUS_LOG_LEVEL=DEBUG

To force the usage of the DBus session bus, enable the ``SIMPLEDBUS_USE_SESSION_DBUS`` flag ::

   cmake -H <path-to-simpledbus> -B build_simpledbus -DSIMPLEDBUS_USE_SESSION_DBUS=TRUE

Installing SimpleDBus
----------------------

To install SimpleDBus, you can use the following commands: ::

   cmake --install build_simpledbus

Note that if you want to modify the installation configuration, you can do so by passing
additional arguments to the ``cmake`` command. For example, to install the library to
a specific location, set the ``CMAKE_INSTALL_PREFIX`` CMake variable to the desired
location ::

   cmake --install build_simpledbus --prefix /usr/local

Note that on Linux and MacOS, you will need to run the ``cmake --install`` command
with ``sudo`` privileges. ::

   sudo cmake --install build_simpledbus


Usage with CMake (Installed)
============================

Once SimpleDBus has been installed, it can be consumed from within CMake::

   find_package(simpledbus REQUIRED CONFIG)
   target_link_libraries(<your-target> simpledbus::simpledbus)


Usage with CMake (Local)
=============================

You can add the ``simpledbus`` library directory into your project and include it in
your ``CMakeLists.txt`` file ::

   add_subdirectory(<path-to-simpledbus> ${CMAKE_BINARY_DIR}/simpledbus)
   target_link_libraries(<your-target> simpledbus::simpledbus)


Usage with CMake (Vendorized)
=============================

If you want to use a vendorized copy of SimpleDBus, you can do so by using FetchContent
and specifying the location from where SimpleDBus should be consumed from. ::

   include(FetchContent)
   FetchContent_Declare(
       simpledbus
       GIT_REPOSITORY <simpledbus-git-repository>
       GIT_TAG <simpledbus-git-tag>
       GIT_SHALLOW YES
   )

   # Note that here we manually do what FetchContent_MakeAvailable() would do,
   # except to ensure that the dependency can also get what it needs, we add
   # custom logic between the FetchContent_Populate() and add_subdirectory()
   # calls.
   FetchContent_GetProperties(simpledbus)
   if(NOT simpledbus_POPULATED)
       FetchContent_Populate(simpledbus)
       list(APPEND CMAKE_MODULE_PATH "${simpledbus_SOURCE_DIR}/cmake/find")
       add_subdirectory("${simpledbus_SOURCE_DIR}/simpledbus" "${simpledbus_BINARY_DIR}")
   endif()

   set(simpledbus_FOUND 1)

You can put this code inside ``Findsimpledbus.cmake`` and add it to your CMake
module path, as depicted in `cmake-init-fetchcontent`_.

Once vendorized using the above approach, you can consume SimpleDBus from
within CMake as you'd normally do ::

   find_package(simpledbus REQUIRED)
   target_link_libraries(<your-target> simpledbus::simpledbus)

One key security feature of SimpleDBus is that it allows the user to specify
the URLs and tags of all internal dependencies, thus allowing compilation
from internal or secure sources without the risk of those getting compromised.

Currently, the following libraries are included as part of SimpleDBus, with
the following CMake options available:

- `fmtlib`_

  - ``LIBFMT_VENDORIZE``: Enable vendorization of fmtlib. *(Default: True)*

  - ``LIBFMT_GIT_REPOSITORY``: The git repository to use for fmtlib.

  - ``LIBFMT_GIT_TAG``: The git tag to use for fmtlib. *(Default: v8.1.1)*

  - ``LIBFMT_LOCAL_PATH``: The local path to use for fmtlib. *(Default: None)*


Build Examples
==============

Use the following instructions to build the provided SimpleDBus examples: ::

   cmake -H <path-to-simpledbus>/examples/simpledbus -B build_simpledbus_examples -DSIMPLEDBUS_LOCAL=ON
   cmake --build build_simpledbus_examples -j7


Testing
=======

To build and run unit and integration tests, the following packages are
required: ::

   sudo apt install libgtest-dev libgmock-dev python3-dev
   pip3 install -r <path-to-simpledbus>/test/requirements.txt


Unit Tests
----------

To run the unit tests, run the following command: ::

   cmake -H <path-to-simpledbus> -B build_simpledbus_test -DSIMPLEDBUS_TEST=ON
   cmake --build build_simpledbus_test -j7
   ./build_simpledbus_test/bin/simpledbus_test


Address Sanitizer Tests
-----------------------

To run the address sanitizer tests, run the following command: ::

   cmake -H <path-to-simpledbus> -B build_simpledbus_test -DSIMPLEDBUS_SANITIZE=Address -DSIMPLEDBUS_TEST=ON
   cmake --build build_simpledbus_test -j7
   PYTHONMALLOC=malloc ./build_simpledbus_test/bin/simpledbus_test

It's important for ``PYTHONMALLOC`` to be set to ``malloc``, otherwise the tests will
fail due to Python's memory allocator from triggering false positives.


Thread Sanitizer Tests
----------------------

To run the thread sanitizer tests, run the following command: ::

   cmake -H <path-to-simpledbus> -B build_simpledbus_test -DSIMPLEDBUS_SANITIZE=Thread -DSIMPLEDBUS_TEST=ON
   cmake --build build_simpledbus_test -j7
   ./build_simpledbus_test/bin/simpledbus_test


.. Links

.. _cmake-init-fetchcontent: https://github.com/friendlyanon/cmake-init-fetchcontent

.. _fmtlib: https://github.com/fmtlib/fmt