Components¶

Contents:

Component Structure¶

elos/src/components/<component name>/
├── CMakeLists.txt
├── interface
│   └── elos
│       └── <component name>
│           ├── defines.h
│           └── types.h
├── private
│   ├── <sub component name>
│   │   └── <sub component name>.c
│   └── <component name>
│       └── <component name>.c
└── public
    └── elos
        └── <component name>
            └── <component name>.h

interface¶

Contain header files only shared inside the elos build.

Header-files C-Source-files

target_addinclude_dir(xyt INTERFACE ./interface/)

private¶

Contain the actual source files.

Header-files are private and only used by the c-files in private. Use include #include “my_private.h”
function in c-files have only public linkage if corresponding protoytpe is defined in a headerifle in public.

public¶

Contain header files that should be packaged and deployed with elos.

means link private-code into target which using public interface, avoid static linking

Header-files C-Source-files : No c-Files shall be in public

define components to be installed¶

Build results¶

elos/build/<build type>/cmake/src/eventprocessor/
├── CMakeFiles
│   └── ...
├── cmake_install.cmake
├── lib<component name>_static.a
└── lib<component name>_static_weak.a

lib<component name>_static.a: * linked into the final binary * target for unit tests
lib<component name>_static_weak.a: * copy of the lib<component name>_static.a but with the functions symbols are marked as weak to enable mocking * target for unit test if mocking of internal functions is required * used for unit test of other components if mocking is required
header files to be deployed

Unit tests¶

Typically each c-Files get compiled as object file and collected in the corresponding lib<component name>_static.a. So for each c-files a corresponding unit test suite shall exists. See [../test/index.rst] for details on how to write and utilise unit test.

Component Interface¶

Elos use a unified set of functions for a component or object. All are optional and shall be only implemented if needed, but if needed use the corresponding prototype below:

/**
 * Allocate memory for `sizeof(elosComponent_t)` and store the address in
 * `component*` pointer.
 * Shall call elosComponentNameInitialize.
 * If the function failed `component*` shall be unchanged.
 *
 * Parameter:
 *     component (elosComponent_t**): point to a elosComponent_t pointer, where
 *                                    to store address of the new allocated
 *                                    object. Shall be unchanged on failure.
 *
 * Returns:
 *     safuResultE_t:
 *         SAFU_RESULT_OK – on success.
 *         SAFU_RESULT_FAILURE – on failure.
 */
safuResultE_t elosComponentNameNew(elosComponent_t **component);

/**
 * Initialize the component with default values to be safely used.
 *
 * Parameter:
 *     component (elosComponent_t*): point to a elosComponent_t, which shall be
 *                                   initialized with defaults.
 *
 * Returns:
 *     safuResultE_t:
 *         SAFU_RESULT_OK – on success.
 *         SAFU_RESULT_FAILURE – on failure.
 */
safuResultE_t elosComponentNameInitialize(elosComponent_t *component);

/**
 * Copy the memory contents to a elosComponent_t from a source elosComponent_t
 * and also make a deep copy each member.
 *
 * Parameter:
 *     to (elosComponent_t*): pointer to the destination component, on failure
 *                            the state of  elosComponent_t shall be unchanged.
 *     from (elosComponent_t*): pointer to the source component
 *
 * Returns:
 *     safuResultE_t:
 *         SAFU_RESULT_OK – on success.
 *         SAFU_RESULT_FAILURE – on failure.
 */
safuResultE_t elosComponentNameDeepCopy(elosComponent_t *to, elosComponent_t const *from);

/**
 * Allocate new memory for a elosComponent_t and make a shallow copy of the
 * memory contents of the source elosComponent_t.
 *
 * Parameter:
 *     to (elosComponent_t*): pointer to the destination component pointer, on
 *                            failure the state of  elosComponent_t shall be
 *                            unchanged.
 *     from (elosComponent_t*): pointer to the source component
 *
 * Returns:
 *     safuResultE_t:
 *         SAFU_RESULT_OK – on success.
 *         SAFU_RESULT_FAILURE – on failure.
 */
safuResultE_t elosComponentNameClone(elosComponent_t **to, elosComponent_t const *from);

/**
 * Shall cleanup and free all members of elosComponent_t.
 *
 * Parameter:
 *     component (elosComponent_t*): pointer to a elosComponent_t, of which all
 *                                   memebers shall be freed.
 *
 * Returns:
 *     safuResultE_t:
 *         SAFU_RESULT_OK – on success.
 *         SAFU_RESULT_FAILURE – on failure.
 */
safuResultE_t elosComponentNameDeleteMembers(elosComponent_t *component);

/**
 * Shall free elosComponent_t itself.
 *
 * Parameter:
 *     component (elosComponent_t*): pointer to a elosComponent_t, which shall
 *                                   be freed.
 *
 * Returns:
 *     safuResultE_t:
 *         SAFU_RESULT_OK – on success.
 *         SAFU_RESULT_FAILURE – on failure.
 */
safuResultE_t elosComponentNameDelete(elosComponent_t *component);

Build process in detail¶

compile all c-files and collect in static component library -> component ==> static library
create weak component library