urtware / doc / activitydiagrams / subscriber / urtHrtSubscriberFetchLatestMessage.uml @ ee83a495
History | View | Annotate | Download (2.45 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**\nurtHrtSubscriberFetchLatestMessage()\n |
27 |
|
28 |
/'### PARAMETERS & RETURN ####################################################'/ |
29 |
|
30 |
note |
31 |
-- **subscriber** : urt_hrtsubscriber_t* -- |
32 |
The HRT subscriber that shall fetch the message. |
33 |
Must not be ""NULL"". |
34 |
-- **payload** : void* -- |
35 |
Pointer where to copy the payload to. |
36 |
May be ""NULL"" for messages without payload. |
37 |
-- **bytes** : size_t -- |
38 |
Payload size in bytes. |
39 |
-- **latency** : urt_delay_t* -- |
40 |
The latency can be returned by reference. |
41 |
May be ""NULL"". |
42 |
==== |
43 |
-- **return** : urt_status_t -- |
44 |
Returns ""URT_STATUS_OK"" on success. |
45 |
Returns ""URT_STATUS_ERROR"" if the subscriber is not associated to a topic. |
46 |
endnote |
47 |
|
48 |
/'### PROCEDURE ##############################################################'/ |
49 |
|
50 |
start |
51 |
if (Associated to a topic?) then (yes) |
52 |
:lock topic; |
53 |
:access last read message; |
54 |
while (Timestamp of next message is younger?) is (yes) |
55 |
fork |
56 |
:proceed to next message; |
57 |
fork again |
58 |
:decrement next message's HRT counter; |
59 |
endfork |
60 |
endwhile (no) |
61 |
fork |
62 |
!include fetchmessage.iuml |
63 |
fork again |
64 |
if (The HRT counter of any message became 0?) then (yes) |
65 |
:signal topic's condition variable; |
66 |
else (no) |
67 |
endif |
68 |
fork again |
69 |
:reset QoS delay timer; |
70 |
endfork |
71 |
:unlock topic; |
72 |
stop |
73 |
note |
74 |
Returns ""URT_STATUS_OK"". |
75 |
endnote |
76 |
else (no) |
77 |
stop |
78 |
note |
79 |
Returns ""URT_STATUS_ERROR"". |
80 |
endnote |
81 |
endif |
82 |
|
83 |
/'### OUTRO ##################################################################'/ |
84 |
|
85 |
@enduml |