libalarm Documentation

Author:

Simo Piiroinen <simo.piiroinen@nokia.com>

Copyright

Alarm daemon and libalarm are:
Copyright (C) 2008 Nokia. All rights reserved.

Introduction

Alarm service is a subsysten that consists of two parts:

• alarmd - daemon process that keeps track of current alarms
• libalarm - client library for accessing the alarm data

Architecture

Simplified view to system utilizing alarm service:

• Alarm daemon supports any number of clients
• Application code includes libalarm.h
• Application binary is linked against libalarm.so
• Libalarm utilizes D-Bus to communicate with the server
• Alarm daemon accepts request on dbus
• Alarm data is stored to a file
• HW RTC can be used to boot up the device
• Triggered alarms are send to system ui dialog service
• System ui sends user response back to alarmd
• Snooze / Execute / D-Bus action is performed by alarm daemon

ASCII art diagram of the above:

   +----------+  +-------+  +-------+
   |          |  |       |  |       |
   | calendar |  | clock |  | app X |
   |          |  |       |  |       |
 ======================================  libalarm.h
               |          |
               | libalarm |
               |          |
               +----------+
                    ^
                    |
                  ==z=== D-Bus
                    |
                    v
               +---------+
               |         |            +---------+
               |         |<-----------| snooze  |
               |         |            +---------+
               | alarmd  |                  ^
               |         |                  |
  +-------+    |         |            +------------------+
  | alarm |<-->|         |----------->|  alarm action    |
  | queue |    +---------+            +------------------+
  | file  |     ^     | ^                   |          |
  +-------+     |     | |            exec ==z==      ==z== D-Bus
                |     | |                   |          |
                |     | |                   v          v
       ioctl ===z== ==z=z=== D-Bus    +---------+ +-------------+
                |     | |             |         | | dbus signal |
                v     v |             | command | | or method   |
      +----------+  +----------+      |         | | call        |
      |          |  | systemui |      +---------+ +-------------+
      | /dev/rtc |  | dialog   |
      |          |  | service  |
      +----------+  +----------+
                        ^
                        |
                      ==z=== Touchscreen
                        |
                        v
                    +----------+
                    | response |
                    | from the |
                    | user     |
                    +----------+

SVN

All source code is stored in subversion repository dms, subdirectory alarmd.

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