AMiRo-OS

/'

µRtWare is a lightweight publish/subscribe middleware for real-time

applications. It was developed as part of the software habitat for the

Autonomous Mini Robot [1] (AMiRo) but can be used for other purposes as well.

Copyright (C) 2018..2020  Thomas Schöpping et al.

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 3 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, see <http://www.gnu.org/licenses/>.

'/

/'### INTRO ##################################################################'/

@startuml

title **µRtWare**\nurtPublisherPublish()\n

/'### PARAMETERS & RETURN ####################################################'/

note

  -- **publisher** : urt_publisher_t* --

  Pointer to the publisher to use.

  Must not be ""NULL"".

  -- **payload** : void* --

  Pointer to the data to be published.

  May be ""NULL"" for messages without payload.

  -- **bytes** : size_t --

  Size of the payload in bytes.

  -- **t** : urt_osTime_t --

  Timestamp to be set for the message.

  -- **timeout** : urt_delay_t --

  Timeout delay in case the message cannot be published.

  This parameter is only available if ""URT_PUBSUB_PUBLISHER_PUBLISH_TIMEOUT"" is ""true"".

  ====

  -- **return** : urt_status_t --

  Returns ""URT_STATUS_OK"" on success.

  Returns ""URT_STATUS_PUBLISH_TIMEOUT"" on timeout.

endnote

/'### PROCEDURE ##############################################################'/

start

:lock topic;

fork

  :access topic's next message;

fork again

  #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..\nincrement counter of publish attempts;

endfork

while (HRT consumers left for the message?) is (yes)

  :wait for topic's condition variable (using topic's mutex) to be signaled or timeout;

  if (Timeout occurred?) then (yes)

    #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..\nincrement counter of publish fails;

    :unlock topic;

    stop

    note

      Returns ""URT_STATUS_PUBLISH_TIMEOUT"".

    endnote

  else (no)

    if (Message timestamp was modified?) then (yes)

      repeat

        :proceed to next message;

      repeat while (Timestamp is younger than of previous message?) is (yes)

      ->no;

    else (no)

    endif

  endif

endwhile (no)

partition "//URT_CFG_PUBSUB_PROFILING == true//" #EEEEEE {

  if (Consumers left for this message?) then (yes)

    #EEEEEE:increment counter of discarded messages (@topic);

  else (no)

  endif

}

fork

  partition "setup message" {

    fork

      :iterate topic's pointer to this message;

    fork again

      :copy payload to message;

    fork again

      :set origin time of message;

    fork again

      :set number of HRT consumers (from topic);

    fork again

      #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..

       set numer of consumers (from topic);

    endfork

  }

fork again

  #EEEEEE:..//URT_CFG_PUBSUB_QOS_RATECHECKS == true//..\nset QoS rate timer (@topic) wrt. most critical HRT subscriber;

fork again

  partition "//URT_CFG_PUBSUB_QOS_DEADLINECHECKS == true//" #EEEEEE {

    #EEEEEE:access first HRT subscriber of topic;

    while (HRT subscriber is not ""NULL""?) is (yes)

      if (QoS deadline timer (@subscriber) is not armed?) then (yes)

        #EEEEEE:set QoS deadline timer (@subscriber) wrt. origin time of the message;

        note

          No lock required.

          This timer is only accessed while topic is locked.

        endnote

      else (no)

      endif

      #EEEEEE:proceed to next HRT subscriber;

    endwhile (no)

  }

fork again

  #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..\nincrement counter of published messages (@topic);

endfork

:fire event;

note: Msut be within topic lock because of HRT counter.

:unlock topic;

stop

note

 Returns ""URT_STATUS_OK"".

endnote

/'### OUTRO ##################################################################'/

@enduml