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**\nurtSubscriberUnsubscribe()\n

!include ../../functions.iuml

/'### PARAMETERS & START #####################################################'/

start

note

  -- ""**subscriber** : urt_subscriber_t*"" --

  The subscriber to be unsubscribed.

  Must not be ""NULL"".

end note

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

if (Associated to a topic?) then (yes)

  if (Is HRT subscriber?) then (yes)

    :lock topic;

    fork

      :unregister event;

      note: Must be within lock because of HRT counter.

    fork again

      :decrement topic's HRT counter;

    fork again

      :remove self from topic's list of HRT subscribers;

      if (Was most critical subscriber?) then (yes)

        :update QoS rate timer (@topic);

      else (no)

      endif

    fork again

      while (Unfetched messages left?) is (yes)

        :lock message;

        :decrement HRT counter;

        :unlock message;

      endwhile (no)

      if (At least one HRT counter became 0?) then (yes)

        :signal topic's condition variable;

      else (no)

      endif

    endfork

    :unlock topic;

  else (no)

    :unregister event;

  endif

  :reset members;

  :return ""URT_STATUS_OK"";

else (no)

  :return ""URT_STATUS_ERROR"";

endif

/'### STOP & RETURN ##########################################################'/

stop

note

  -- **return** ""urt_status_t"" --

  Returns ""URT_STATUS_ERROR"" if the subscriber was not associated to any topic.

end note

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

@enduml