Class: Flog

Inherits:
MethodBasedSexpProcessor
  • Object
show all
Defined in:
lib/flog.rb

Overview

Flog is a SexpProcessor that calculates a ABC (assignments, branches, conditionals) complexity metric with some ruby-aware enhancements and a compounding penalty for increasing depth.

In essence, this calculates the most tortured code. The higher the score, the more pain the code is in and the harder it is to thoroughly test.

Constant Summary collapse

VERSION =

:nodoc:

"4.8.0"
DEFAULT_THRESHOLD =

Cut off point where the report should stop unless –all given.

0.60
THRESHOLD =

:nodoc:

DEFAULT_THRESHOLD
SCORES =

The scoring system hash. Maps node type to score.

Hash.new 1
BRANCHING =

Names of nodes that branch.

[ :and, :case, :else, :if, :or, :rescue, :until, :when, :while ]
OTHER_SCORES =

Various non-call constructs

{
  :alias          => 2,
  :assignment     => 1,
  :block          => 1,
  :block_pass     => 1,
  :block_call     => 1,
  :branch         => 1,
  :magic_number   => 0.25,
  :sclass         => 5,
  :super          => 1,
  :to_proc_icky!  => 10,
  :to_proc_lasgn  => 15,
  :yield          => 1,
}
Rational =

1.8 / 1.9

Integer

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(option = {}) ⇒ Flog

Creates a new Flog instance with options.



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# File 'lib/flog.rb', line 227

def initialize option = {}
  super()
  @option              = option
  @mass                = {}
  @parser              = nil
  @threshold           = option[:threshold] || DEFAULT_THRESHOLD
  self.auto_shift_type = true
  self.reset
end

Instance Attribute Details

#calls ⇒ Object (readonly)

Returns the value of attribute calls.



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# File 'lib/flog.rb', line 92

def calls
  @calls
end

#mass ⇒ Object (readonly)

Returns the value of attribute mass.



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# File 'lib/flog.rb', line 92

def mass
  @mass
end

#method_scores ⇒ Object (readonly)

Returns the value of attribute method_scores.



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# File 'lib/flog.rb', line 93

def method_scores
  @method_scores
end

#multiplier ⇒ Object

:stopdoc:



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# File 'lib/flog.rb', line 91

def multiplier
  @multiplier
end

#option ⇒ Object (readonly)

Returns the value of attribute option.



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# File 'lib/flog.rb', line 92

def option
  @option
end

#scores ⇒ Object (readonly)

Returns the value of attribute scores.



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# File 'lib/flog.rb', line 93

def scores
  @scores
end

#threshold ⇒ Object

Final threshold that is used for report



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# File 'lib/flog.rb', line 293

def threshold
  option[:all] ? nil : total_score * @threshold
end

#total_score ⇒ Object (readonly)

Returns the value of attribute total_score.



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# File 'lib/flog.rb', line 94

def total_score
  @total_score
end

#totals ⇒ Object (readonly)

Returns the value of attribute totals.



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# File 'lib/flog.rb', line 94

def totals
  @totals
end

Instance Method Details

#add_to_score(name, score = ) ⇒ Object

Add a score to the tally. Score can be predetermined or looked up automatically. Uses multiplier for additional spankings. Spankings!



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# File 'lib/flog.rb', line 104

def add_to_score name, score = OTHER_SCORES[name]
  return if option[:methods] and method_stack.empty?
  @calls[signature][name] += score * @multiplier
end

#alias_method ⇒ Object

Various “magic” usually used for “clever code”



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# File 'lib/flog.rb', line 64

SCORES.merge!(:alias_method               => 2,
:extend                     => 2,
:include                    => 2,
:instance_method            => 2,
:instance_methods           => 2,
:method_added               => 2,
:method_defined?            => 2,
:method_removed             => 2,
:method_undefined           => 2,
:private_class_method       => 2,
:private_instance_methods   => 2,
:private_method_defined?    => 2,
:protected_instance_methods => 2,
:protected_method_defined?  => 2,
:public_class_method        => 2,
:public_instance_methods    => 2,
:public_method_defined?     => 2,
:remove_method              => 2,
:send                       => 3,
:undef_method               => 2)

#average ⇒ Object

really?



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# File 'lib/flog.rb', line 112

def average
  return 0 if calls.size == 0
  total_score / calls.size
end

#calculate ⇒ Object

Calculates classes and methods scores.



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# File 'lib/flog.rb', line 120

def calculate
  each_by_score threshold do |class_method, score, call_list|
    klass = class_method.scan(/.+(?=#|::)/).first

    method_scores[klass] << [class_method, score]
    scores[klass] += score
  end
end

#calculate_total_scores ⇒ Object

Calculates the total score and populates @totals.



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# File 'lib/flog.rb', line 300

def calculate_total_scores
  return if @totals

  @total_score = 0
  @totals = Hash.new(0)

  calls.each do |meth, tally|
    score = score_method(tally)

    @totals[meth] = score
    @total_score += score
  end
end

#define_method ⇒ Object

Eval forms



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# File 'lib/flog.rb', line 55

SCORES.merge!(:define_method => 5,
:eval          => 5,
:module_eval   => 5,
:class_eval    => 5,
:instance_eval => 5)

#dsl_name?(args) ⇒ Boolean

Returns true if the form looks like a “DSL” construct.

task :blah do ... end
=> s(:iter, s(:call, nil, :task, s(:lit, :blah)), ...)

Returns:

  • (Boolean) 


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# File 'lib/flog.rb', line 135

def dsl_name? args
  return false unless args and not args.empty?

  first_arg, = args
  first_arg = first_arg[1] if first_arg.sexp_type == :hash

  type, value, * = first_arg

  value if [:lit, :str].include? type
end

#each_by_score(max = nil) ⇒ Object

Iterate over the calls sorted (descending) by score.



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# File 'lib/flog.rb', line 149

def each_by_score max = nil
  current = 0

  calls.sort_by { |k,v| -totals[k] }.each do |class_method, call_list|
    score = totals[class_method]

    yield class_method, score, call_list

    current += score
    break if max and current >= max
  end
end

#flog(*files) ⇒ Object

Flog the given files. Deals with “-”, and syntax errors.

Not as smart as FlogCLI’s #flog method as it doesn’t traverse dirs. Use PathExpander to expand dirs into files.



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# File 'lib/flog.rb', line 168

def flog(*files)
  files.each do |file|
    next unless file == "-" or File.readable? file

    ruby = file == "-" ? $stdin.read : File.binread(file)

    flog_ruby ruby, file
  end

  calculate_total_scores
end

#flog_ruby(ruby, file = "-", timeout = 10) ⇒ Object

Flog the given ruby source, optionally using file to provide paths for methods. Smart. Handles syntax errors and timeouts so you don’t have to.



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# File 'lib/flog.rb', line 185

def flog_ruby ruby, file="-", timeout = 10
  flog_ruby! ruby, file, timeout
rescue Timeout::Error
  warn "TIMEOUT parsing #{file}. Skipping."
rescue RubyParser::SyntaxError, Racc::ParseError => e
  q = option[:quiet]
  if e.inspect =~ /<\%|%\>/ or ruby =~ /<\%|%\>/ then
    return if q
    warn "#{e.inspect} at #{e.backtrace.first(5).join(", ")}"
    warn "\n...stupid lemmings and their bad erb templates... skipping"
  else
    warn "ERROR: parsing ruby file #{file}" unless q
    unless option[:continue] then
      warn "ERROR! Aborting. You may want to run with --continue."
      raise e
    end
    return if q
    warn "%s: %s at:\n  %s" % [e.class, e.message.strip,
                               e.backtrace.first(5).join("\n  ")]
  end
end

#flog_ruby!(ruby, file = "-", timeout = 10) ⇒ Object

Flog the given ruby source, optionally using file to provide paths for methods. Does not handle timeouts or syntax errors. See #flog_ruby.



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# File 'lib/flog.rb', line 211

def flog_ruby! ruby, file="-", timeout = 10
  @parser = (option[:parser] || RubyParser).new

  warn "** flogging #{file}" if option[:verbose]

  ast = @parser.process ruby, file, timeout

  return unless ast

  mass[file] = ast.mass
  process ast
end

#inject ⇒ Object

Calls that are ALMOST ALWAYS ABUSED!



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# File 'lib/flog.rb', line 88

SCORES.merge!(:inject => 2)

#max_method ⇒ Object

Returns the method/score pair of the maximum score.



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# File 'lib/flog.rb', line 240

def max_method
  totals.max_by { |_, score| score }
end

#max_score ⇒ Object

Returns the maximum score for a single method. Used for FlogTask.



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# File 'lib/flog.rb', line 247

def max_score
  max_method.last
end

#no_method ⇒ Object

:nodoc:



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# File 'lib/flog.rb', line 314

def no_method # :nodoc:
  @@no_method
end

#penalize_by(bonus) ⇒ Object

For the duration of the block the complexity factor is increased by #bonus This allows the complexity of sub-expressions to be influenced by the expressions in which they are found. Yields 42 to the supplied block.



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# File 'lib/flog.rb', line 257

def penalize_by bonus
  @multiplier += bonus
  yield
  @multiplier -= bonus
end

#process_alias(exp) ⇒ Object

:stopdoc:



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# File 'lib/flog.rb', line 322

def process_alias(exp)
  process exp.shift
  process exp.shift
  add_to_score :alias
  s()
end

#process_and(exp) ⇒ Object Also known as: process_or 



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# File 'lib/flog.rb', line 329

def process_and(exp)
  add_to_score :branch
  penalize_by 0.1 do
    process exp.shift # lhs
    process exp.shift # rhs
  end
  s()
end

#process_attrasgn(exp) ⇒ Object 



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# File 'lib/flog.rb', line 339

def process_attrasgn(exp)
  add_to_score :assignment
  process exp.shift # lhs
  exp.shift # name
  process_until_empty exp # rhs
  s()
end

#process_block(exp) ⇒ Object 



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# File 'lib/flog.rb', line 347

def process_block(exp)
  penalize_by 0.1 do
    process_until_empty exp
  end
  s()
end

#process_block_pass(exp) ⇒ Object 



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# File 'lib/flog.rb', line 354

def process_block_pass(exp)
  arg = exp.shift

  add_to_score :block_pass

  return s() unless arg

  case arg.sexp_type
  when :lvar, :dvar, :ivar, :cvar, :self, :const, :colon2, :nil then # f(&b)
    # do nothing
  when :lit then                                                     # f(&:b)
    # do nothing -- this now costs about the same as a block
  when :call then                                                    # f(&x.b)
    # do nothing -- I don't like the indirection, but that's already scored
  when :lasgn then                                                   # f(&l=b)
    add_to_score :to_proc_lasgn
  when :iter, :dsym, :dstr, :hash, *BRANCHING then                   # below
    # f(&proc { ... })
    # f(&"#{...}")
    # f(&:"#{...}")
    # f(&if ... then ... end") and all other branching forms
    # f(&{ a: 42 })  WHY?!?
    add_to_score :to_proc_icky!
  else
    raise({:block_pass_even_ickier! => arg}.inspect)
  end

  process arg

  s()
end

#process_call(exp) ⇒ Object 



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# File 'lib/flog.rb', line 386

def process_call(exp)
  penalize_by 0.2 do
    process exp.shift # recv
  end

  name = exp.shift

  penalize_by 0.2 do
    process_until_empty exp
  end

  add_to_score name, SCORES[name]

  s()
end

#process_case(exp) ⇒ Object 



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# File 'lib/flog.rb', line 418

def process_case(exp)
  add_to_score :branch
  process exp.shift # recv
  penalize_by 0.1 do
    process_until_empty exp
  end
  s()
end

#process_class(exp) ⇒ Object 



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# File 'lib/flog.rb', line 427

def process_class(exp)
  super do
    penalize_by 1.0 do
      process exp.shift # superclass expression
    end
    process_until_empty exp
  end
end

#process_dasgn_curr(exp) ⇒ Object Also known as: process_iasgn, process_lasgn

FIX: remove



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# File 'lib/flog.rb', line 436

def process_dasgn_curr(exp) # FIX: remove
  add_to_score :assignment
  exp.shift # name
  process exp.shift # assigment, if any
  s()
end

#process_else(exp) ⇒ Object Also known as: process_rescue, process_when

TODO: it’s not clear to me whether this can be generated at all.



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# File 'lib/flog.rb', line 446

def process_else(exp)
  add_to_score :branch
  penalize_by 0.1 do
    process_until_empty exp
  end
  s()
end

#process_if(exp) ⇒ Object 



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# File 'lib/flog.rb', line 456

def process_if(exp)
  add_to_score :branch
  process exp.shift # cond
  penalize_by 0.1 do
    process exp.shift # true
    process exp.shift # false
  end
  s()
end

#process_iter(exp) ⇒ Object 



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# File 'lib/flog.rb', line 466

def process_iter(exp)
  context = (self.context - [:class, :module, :scope])
  context = context.uniq.sort_by { |s| s.to_s }

  exp.delete 0 # { || ... } has 0 in arg slot

  if context == [:block, :iter] or context == [:iter] then
    recv, = exp

    # DSL w/ names. eg task :name do ... end
    #   looks like s(:call, nil, :task, s(:lit, :name))
    #           or s(:call, nil, :task, s(:str, "name"))
    #           or s(:call, nil, :task, s(:hash, s(:lit, :name) ...))

    t, r, m, *a = recv

    if t == :call and r == nil and submsg = dsl_name?(a) then
      m = "#{m}(#{submsg})" if m and [String, Symbol].include?(submsg.class)
      in_klass m do                             # :task/namespace
        in_method submsg, exp.file, exp.line, exp.line_max do # :name
          process_until_empty exp
        end
      end
      return s()
    end
  end

  add_to_score :block_call

  process exp.shift # no penalty for LHS

  penalize_by 0.1 do
    process_until_empty exp
  end

  s()
end

#process_lit(exp) ⇒ Object 



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# File 'lib/flog.rb', line 506

def process_lit(exp)
  value = exp.shift
  case value
  when 0, -1 then
    # ignore those because they're used as array indicies instead of
    # first/last
  when Integer, Float, Rational, Complex then
    add_to_score :magic_number unless context[1] == :cdecl
  when Symbol, Regexp, Range then
    # do nothing
  else
    raise "Unhandled lit: #{value.inspect}:#{value.class}"
  end
  s()
end

#process_masgn(exp) ⇒ Object 



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# File 'lib/flog.rb', line 522

def process_masgn(exp)
  add_to_score :assignment

  exp.map! { |s| Sexp === s ? s : s(:lasgn, s) }

  process_until_empty exp
  s()
end

#process_safe_call(exp) ⇒ Object 



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# File 'lib/flog.rb', line 402

def process_safe_call(exp)
  penalize_by 0.3 do
    process exp.shift # recv
  end

  name = exp.shift

  penalize_by 0.2 do
    process_until_empty exp
  end

  add_to_score name, SCORES[name]

  s()
end

#process_sclass(exp) ⇒ Object 



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# File 'lib/flog.rb', line 531

def process_sclass(exp)
  super do
    penalize_by 0.5 do
      process exp.shift # recv
      process_until_empty exp
    end
  end

  add_to_score :sclass
  s()
end

#process_super(exp) ⇒ Object 



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# File 'lib/flog.rb', line 543

def process_super(exp)
  add_to_score :super
  process_until_empty exp
  s()
end

#process_while(exp) ⇒ Object Also known as: process_until 



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# File 'lib/flog.rb', line 549

def process_while(exp)
  add_to_score :branch
  penalize_by 0.1 do
    process exp.shift # cond
    process exp.shift # body
  end
  exp.shift # pre/post
  s()
end

#process_yield(exp) ⇒ Object 



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# File 'lib/flog.rb', line 560

def process_yield(exp)
  add_to_score :yield
  process_until_empty exp
  s()
end

#reset ⇒ Object

Reset score data



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# File 'lib/flog.rb', line 266

def reset
  @totals           = @total_score = nil
  @multiplier       = 1.0
  @calls            = Hash.new { |h,k| h[k] = Hash.new 0 }
  @method_scores    = Hash.new { |h,k| h[k] = [] }
  @scores           = Hash.new 0
  method_locations.clear
end

#score_method(tally) ⇒ Object

Compute the distance formula for a given tally



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# File 'lib/flog.rb', line 278

def score_method(tally)
  a, b, c = 0, 0, 0
  tally.each do |cat, score|
    case cat
    when :assignment then a += score
    when :branch, :block_call then b += score
    else                  c += score
    end
  end
  Math.sqrt(a*a + b*b + c*c)
end