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  1. Qt
  2. QTBUG-25883

Implement a Reading FIFO (source-incompatible)

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    Details

    • Type: User Story
    • Status: Withdrawn
    • Priority: P3: Somewhat important
    • Resolution: Out of scope
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: Sensors
    • Labels:
      None

      Description

      Overview

      There will be a FIFO inside each sensor.

      The backend supplies readings to the FIFO. The application pulls items out of the FIFO.

      void MyClass::onNewSensorData()
      {
          while (sensor->readingsAvailable())
              do_something(sensor->takeReading());
      }
      

      Implementation Plan

      Remove the reading() method. Add a takeReading() and a readingsAvailable() method.

      The readingChanged() signal will be replaced with a newSensorDataAvailable() signal.

      The actual FIFO should be a class that's visible to QSensor and to the backend.

      Notes

      A source-compatible implementation could possibly be done if we use some policy. This would enable the feature to be rolled out to existing users without requiring them to port to a new library. The existing reading method would point to the front of the queue, the queue would replace old with new values and would default to a depth of 1.

      Research Questions

      Maybe some better method/signal names can be found?

      What does example app code look like?

      How can we unit test this (should be easy if it's a self-contained class)?

      How can we document this (should be mostly private, just document the methods that are exposed in QSensor)?

      Does this hold pointers (for polymorphism) or a concrete class (in which case how to we expose per-sensor data)? Should the API be in the sub-classes of QSensor?

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            People

            Assignee:
            lpotter Lorn Potter
            Reporter:
            lramsay Lincoln Ramsay (closed Nokia identity) (Inactive)
            PM Owner:
            Veli-Pekka Heinonen Veli-Pekka Heinonen
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              Dates

              Created:
              Updated:
              Resolved:

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