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Code Organization and Cleanup Project


Status: This specification is implemented.

Mixxx has over 400 source files, all of which are stored alone in the 'src' directory. As Mixxx is gaining contributors, it is important for the source tree to be well organized and furthermore that it reflects the organization of Mixxx itself. This will allow new contributors to more easily be able to pick a specific module of Mixxx to contribute to without having to understand the whole system, as well as making it easier on the core developers when adding new features. It will also encourage more thought when adding new code. For example, if you are about to add a class to the widget folder that does a fair amount of 'music logic', it shouldn't feel 'right'.

Another potential idea is to standardize the headers of files across the project. Currently many of the file headers are the same as when they were originally written. They vary in their mention of the GPL, and most all lack a summary of the logic/code contained in the file. We should standardize on a top header that mentions the project, the project website, and a brief summary of what goes on in the file. The original author, start date, and email can stay because it's useful information, but it can contribute to people feeling like they are touching “someone else's code.” How Open Source Projects Survive Poisonous People.

Use Cases

  • DJ Bill got a degree in CS and knows some C++. He loves Mixxx and would like to contribute. After discussing with the folks in #mixxx, he decides to take on a 'weekend project' sized feature of adding a new widget to the UI. He is easily able to find the widget code in the 'widget' folder to see an example of a current Mixxx widget. He can easily ignore the engine, soundsource, MIDI, and visual code because they are stored in their appropriate directories.
  • Developer Dan is a longtime Mixxx contributor, but hasn't been keeping up to date with the changes in the most recent release. He takes a look at the svn changelist from since he last contributed, and can see many additions to the 'input', 'widget', and 'engine' folders. He can easily tell where active development has been taking place by which folders have been changed the most.


This change is planned for post 1.6.0 release


The following are overall groups that the code can be grouped into:

  • Input
  • Engine
  • SoundSource
  • Widget
  • Waveform
  • Util
  • Skin
  • Dialog
  • Config
  • MIDI

Deprecated Classes

  • Player, PlayerProxy, PlayerAsio, PlayerPortAudio, PlayerJack, PlayerAlsa, PlayerRTAudio, need to be removed (or moved to 'old').
  • the old visual stuff can be deleted (it lived in 'old')
  • ReaderExtractHFC, ReaderExtractBeat?
  • Mouse, MouseLinux
  • MIDIObjectAlsa? (replaced by alsaseq)
  • WComboBox (replaced by library updates?)
  • WVinylControlIndicator (unused currently – was someone working on this?)

Deprecated Logic

  • Remove 'ping' mode from EngineBuffer
  • WOverview does tons of HFC detection stuff, and does absolutely nothing with it.


  • All files will be moved with the 'svn move' command so that their histories will be preserved within the SCM.


  • All waveform code was put into waveform/
  • All MixxxScript/QtScript code is currently being developed in script/
  • All BPM code was moved into bpm/
  • All LADSPA code (except engineladspa and ladspaview) was moved into ladspa/
  • All widget code (starts with 'w' and inherits QWidget) is now in widget/
  • All MIDI code is in midi/
  • All engine code is in engine/
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code_organization_and_cleanup.txt · Last modified: 2016/05/05 21:59 by rryan