= churn

A Project to give the churn file, class, and method for a project for a given checkin
Over time the tool adds up the history of chruns to give the number of times a file, class, or method is changing during the life of a project.
Churn for files is immediate, but classes and methods requires buildings up a history using churn between revisions. The history is stored in ./tmp

== Example Output
  **********************************************************************
  * Project Churn 
  **********************************************************************
  files: 
   * {:file_path=>"lib/churn/churn_calculator.rb", :times_changed=>11}
   * {:file_path=>"README.rdoc", :times_changed=>6}
   * {:file_path=>"lib/tasks/churn_tasks.rb", :times_changed=>6}
   * {:file_path=>"Rakefile", :times_changed=>4}
   * {:file_path=>"lib/churn/git_analyzer.rb", :times_changed=>4}
   * {:file_path=>"test/test_helper.rb", :times_changed=>4}
   * {:file_path=>"test/unit/churn_calculator_test.rb", :times_changed=>3}
   * {:file_path=>"test/churn_test.rb", :times_changed=>3}
   * {:file_path=>"VERSION", :times_changed=>3}

  classes: 
   * {"klass"=>{"klass"=>"ChurnCalculator", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>7}
   * {"klass"=>{"klass"=>"LocationMapping", "file"=>"lib/churn/location_mapping.rb"}, "times_changed"=>1}
   * {"klass"=>{"klass"=>"GitAnalyzer", "file"=>"lib/churn/git_analyzer.rb"}, "times_changed"=>1}
   * {"klass"=>{"klass"=>"ChurnTest", "file"=>"test/churn_test.rb"}, "times_changed"=>1}
   * {"klass"=>{"klass"=>"ChurnCalculatorTest", "file"=>"test/unit/churn_calculator_test.rb"}, "times_changed"=>1}

  methods: 
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#to_h", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>3}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#analyze", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>2}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#report", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>2}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#calculate_changes!", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#display_array", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#calculate_revision_changes", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#initialize", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#set_source_control", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#get_changes", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#calculate_revision_data", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#emit", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"GitAnalyzer", "method"=>"GitAnalyzer#date_range", "file"=>"lib/churn/git_analyzer.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"", "method"=>"#report_churn", "file"=>"lib/tasks/churn_tasks.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#get_klass_for", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"GitAnalyzer", "method"=>"GitAnalyzer#get_recent_file", "file"=>"lib/churn/git_analyzer.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"GitAnalyzer", "method"=>"GitAnalyzer#get_updated_files_change_info", "file"=>"lib/churn/git_analyzer.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"GitAnalyzer", "method"=>"GitAnalyzer#get_changed_range", "file"=>"lib/churn/git_analyzer.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"ChurnCalculator", "method"=>"ChurnCalculator#parse_logs_for_updated_files", "file"=>"lib/churn/churn_calculator.rb"}, "times_changed"=>1}
   * {"method"=>{"klass"=>"LocationMapping", "method"=>"LocationMapping#process_class", "file"=>"lib/churn/location_mapping.rb"}, "times_changed"=>1}

TODO:
* SVN only supports file
* make storage directory configurable instead of using tmp
* allow passing in directories to churn, directories to ignore
* todo add a filter that allows for other files besides. *.rb

Executable Usage:
* 'gem install churn'
* go to project root run 'churn'

Rake Usage:
* 'gem install churn'
* on any project you want to use churn, add "require 'churn'" to your rake file
* run 'rake churn' to view the current output, file churn history is immediate, class and method churn builds up a history as it is run on each revision
* temporary files with class / method churn history are stored in /tmp, to clear churn history delete them

== Note on Patches/Pull Requests
 
* Fork the project.
* Make your feature addition or bug fix.
* Add tests for it. This is important so I don't break it in a
  future version unintentionally.
* Commit, do not mess with rakefile, version, or history.
  (if you want to have your own version, that is fine but
   bump version in a commit by itself I can ignore when I pull)
* Send me a pull request. Bonus points for topic branches.

== Copyright

Copyright (c) 2009 Dan Mayer. See LICENSE for details.