[RFC] A better dbus gps interface

[Sascha Wessel]

Hi list,


the current frameworkd gps interface is based on Gypsy.
Gypsy was designed for simple server site implementation using c and
based on NMEA sentences. In my opinion a good api should be more
client/user oriented.

Hence, my suggestions for a better dbus gps interface:

* Remove Gypsy server interface -> frameworkd.conf
* Remove Start/Stop methods -> ousaged's RequestResource
* Remove connection status -> ousaged's GetResourceState
* Merge Position, Accuracy and Course (or is it possible that the
  course changes while the position doesn't change and so on?)
* Remove all bitfields and replace by a{sd}
* Replace enum like integers by strings
* Replace this log alike timestamp/bitfield functionality by a more
  powerful log (records configurable in frameworkd.conf)
* Add accuracy for time values (for leap seconds etc.)
* Improve functionality for scripts which just want a position once

*** Methods ***

GetFixStatus() -> s
* Description:
  - Get current fix status.
* Returns:
  - s: status
    - "NO"
    - "2D"
    - "3D"

GetSatellites() -> a{uiuub}
* Description:
  - Get current satellite list.
* Returns:
  - a: array of satellites
    - u: prn
    - i: elevation
    - u: azimuth
    - u: snr
    - b: used


GetData(da{s}) -> dda{sd}
* Description:
  - Get the GPS data near the given time.
  - E.g. get last known 2D position with GetData(INF, ("latitude", "longitude"))
* Parameters:
  - d: time in seconds since epoch
  - a: required tuples (see below)
* Returns:
  - d: time in seconds since epoch
  - d: time accuracy in seconds
  - a: array of tuples
    - ("latitude", double)      # 3D and 2D
    - ("longitude", double)     # 3D and 2D
    - ("altitude", double)      # 3D
    - ("pdop", double)          # 3D
    - ("hdop", double)          # 3D and 2D
    - ("vdop", double)          # 3D
    - ("speed", double)         # 3D and 2D
    - ("heading", double)       # 3D and 2D
    - ("climb", double)         # 3D

RequestDataInterval(d)
* Description:
  - Frequency of occurence of Data signals.
  - Defaults to 1 second
  - Keeps a list of clients like RequestResource (ousaged)
* Parameters:
  - d: seconds between signals (use always the smallest registered value)

RequestSatellitesInterval(d)
* Description:
  - Frequency of occurence of Satellites signals.
* Parameters:
  -d: seconds between signals

UpdateData(u)
* Description:
  - Power on and wait for a fix, emit a Data signal, then power off again.
* Parameters:
  - u: timeout in seconds

*** Signals ***

FixStatus(s)
* Description:
  - Sent, when the fix status changes.
* Parameters:
  - s: status (see GetFixStatus)

Satellites(a{uiuub})
* Description:
  - Sent, when the satellite list changes.
* Parameters:
  - array of satellites (see GetSatellites)

Data(dda{sd})
* Description:
  - Sent, when the GPS data changes.
* Parameters:
  - d: time in seconds since epoch
  - d: time accuracy in seconds
  - a: array of tuples (see GetData)


What do yout think about this?


Greetings,
Sascha