Statistics
| Branch: | Revision:

urtware / doc / activitydiagrams / subscriber / hrtsubscriber / urtHrtSubscriberFetchNextMessage.uml @ dd31cb03

History | View | Annotate | Download (5.74 KB)

1
/'
2
µRtWare is a lightweight publish/subscribe middleware for real-time
3
applications. It was developed as part of the software habitat for the
4
Autonomous Mini Robot [1] (AMiRo) but can be used for other purposes as well.
5

    
6
Copyright (C) 2018..2020  Thomas Schöpping et al.
7

    
8
This program is free software: you can redistribute it and/or modify
9
it under the terms of the GNU General Public License as published by
10
the Free Software Foundation, either version 3 of the License, or
11
(at your option) any later version.
12

    
13
This program is distributed in the hope that it will be useful,
14
but WITHOUT ANY WARRANTY; without even the implied warranty of
15
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16
GNU General Public License for more details.
17

    
18
You should have received a copy of the GNU General Public License
19
along with this program.  If not, see <http://www.gnu.org/licenses/>.
20
'/
21

    
22
/'### INTRO ##################################################################'/
23

    
24
@startuml
25

    
26
title **µRtWare**\nurtHrtSubscriberFetchNextMessage()\n
27

    
28
!include ../functions.iuml
29

    
30
/'### PARAMETERS & RETURN ####################################################'/
31

    
32
note
33
  -- **subscriber** : urt_hrtsubscriber_t* --
34
  The HRT subscriber that shall fetch the message.
35
  Must not be ""NULL"".
36
  -- **payload** : void* --
37
  Pointer where to copy the payload to.
38
  May be ""NULL"" for messages without payload.
39
  -- **bytes** : size_t --
40
  Payload size in bytes.
41
  -- **latency** : urt_delay_t* --
42
  The latency can be returned by reference.
43
  May be ""NULL"".
44
  ====
45
  -- **return** : urt_status_t --
46
  Returns ""URT_STATUS_OK"" on success.
47
  Returns ""URT_STATUS_FETCH_NOTOPIC"" if the subscriber is not associated to a topic.
48
  Retruns ""URT_STATUS_FETCH_NOMESSAGE"" if there is no new message to fetch.
49
  Returns ""URT_STATUS_JITTERVIOLATION"" if the message's latency violated the maximum expected jitter.
50
endnote
51

    
52
/'### PROCEDURE ##############################################################'/
53

    
54
start
55
if (Associated to a topic?) then (yes)
56
  :lock topic;
57
  if (Next message is younger?) then (yes)
58
    :proceed to next message;
59
  else (no)
60
    :unlock topic;
61
    stop
62
    note
63
      Returns ""URT_STATUS_FETCH_NOMESSAGE"".
64
    endnote
65
  endif
66
  fork
67
    :calculate message latency;
68
    fork
69
      #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..\naccumulate ""sumLatencies"" value;
70
    fork again
71
      if (Optional ""latency"" output argument given?) then (yes)
72
        :set ""latency"" value;
73
      else (no)
74
      endif
75
    endfork
76
  fork again
77
    :decrement message's HRT counter;
78
    if (HRT counter became 0?) then (yes)
79
    else (no)
80
      :signal topic's condition variable;
81
    endif
82
  fork again
83
    partition "//URT_CFG_PUBSUB_PROFILING == true//" #EEEEEE {
84
      fork
85
        #EEEEEE:decrement counter of consumers left (@message);
86
      fork again
87
        #EEEEEE:increment counter of received messages;
88
      endfork
89
    }
90
  endfork
91
  partition "//URT_CFG_PUBSUB_QOS_JITTERCHECKS == true || URT_CFG_PUBSUB_PROFILING == true//" #EEEEEE {
92
    if (Latency is within allowed jitter range?) then (yes)
93
      if (Latency is lower than ""minLatency""?) then (yes)
94
        #EEEEEE:update ""minLatency"" value;
95
      elseif (Latency is greater than ""maxLatency""?) then (yes)
96
        #EEEEEE:update ""maxLatency"" value;
97
      else (no)
98
      endif
99
    else (no)
100
      partition "//URT_CFG_PUBSUB_QOS_JITTERCHECKS == true//" #EEEEEE {
101
        #EEEEEE:unlock topic;
102
        #EEEEEE:call ""urtCoreStopNodes(URT_STATUS_JITTERVIOLATION)"";
103
        stop
104
        note
105
          Returns ""URT_STATUS_JITTERVIOLATION"".
106
        endnote
107
      }
108
    endif
109
  }
110
  fork
111
    $fetch_message()
112
  fork again
113
    partition "//URT_CFG_PUBSUB_QOS_DEADLINECHECKS == true//" #EEEEEE {
114
      if (Timestamp of next message is younger?) then (yes)
115
        #EEEEEE:update QoS deadline timer wrt. next message;
116
      else (no)
117
        #EEEEEE:reset QoS deadline timer;
118
      endif
119
    }
120
  endfork
121

    
122
/'
123
  fork
124
    $fetch_message()
125
  fork again
126
    :calculate message latency;
127
    fork
128
      #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..\naccumulate ""sumLatencies"" value;
129
    fork again
130
      if (Optional ""latency"" output argument given?) then (yes)
131
        :set ""latency"" value;
132
      else (no)
133
      endif
134
    endfork
135
    partition "//URT_CFG_PUBSUB_QOS_JITTERCHECKS == true || URT_CFG_PUBSUB_PROFILING == true//" #EEEEEE {
136
      if (Latency is within allowed jitter range?) then (yes)
137
        if (Latency is lower than ""minLatency""?) then (yes)
138
          #EEEEEE:update ""minLatency"" value;
139
        elseif (Latency is greater than ""maxLatency""?) then (yes)
140
          #EEEEEE:update ""maxLatency"" value;
141
        else (no)
142
        endif
143
      else (no)
144
        :unlock topic;
145
        :call ""urtCoreStopNodes(URT_STATUS_JITTERVIOLATION)"";
146
        stop
147
        note
148
          Returns ""URT_STATUS_JITTERVIOLATION"".
149
        endnote
150
      endif
151
    }
152
  fork again
153
    :decrement message's HRT counter;
154
    if (HRT counter became 0?) then (yes)
155
    else (no)
156
      :signal topic's condition variable;
157
    endif
158
  fork again
159
    partition "//URT_CFG_PUBSUB_QOS_DEADLINECHECKS == true//" #EEEEEE {
160
      if (Timestamp of next message is younger?) then (yes)
161
        #EEEEEE:update QoS deadline timer wrt. next message;
162
      else (no)
163
        #EEEEEE:reset QoS deadline timer;
164
      endif
165
    }
166
  fork again
167
    partition "//URT_CFG_PUBSUB_PROFILING == true//" #EEEEEE {
168
      fork
169
        #EEEEEE:decrement counter of consumers left (@message);
170
      fork again
171
        #EEEEEE:increment counter of received messages;
172
      endfork
173
    }
174
  endfork
175
'/
176

    
177
  :unlock topic;
178
  stop
179
  note
180
    Returns ""URT_STATUS_OK"".
181
  endnote
182
else (no)
183
  stop
184
  note
185
    Returns ""URT_STATUS_FETCH_NOTOPIC"".
186
  endnote
187
endif
188

    
189
/'### OUTRO ##################################################################'/
190

    
191
@enduml