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Class: RuboCop::Cop::Style::BitwisePredicate

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/bitwise_predicate.rb

Overview

Prefer bitwise predicate methods over direct comparison operations.

Examples:

# bad - checks any set bits
(variable & flags).positive?

# good
variable.anybits?(flags)

# bad - checks all set bits
(variable & flags) == flags

# good
variable.allbits?(flags)

# bad - checks no set bits
(variable & flags).zero?

# good
variable.nobits?(flags)

Cop Safety Information:

  • This cop is unsafe, as it can produce false positives if the receiver is not an Integer object.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::TargetRubyVersion - Extended

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns a url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect,
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?,
#target_gem_version

Returns a gems locked versions (i.e.

#target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#allbits?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/bitwise_predicate.rb', line 52

def_node_matcher :allbits?, <<~PATTERN
  {
    (send (begin (send _ :& _flags)) :== _flags)
    (send (begin (send _flags :& _)) :== _flags)
  }
PATTERN

#anybits?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/bitwise_predicate.rb', line 42

def_node_matcher :anybits?, <<~PATTERN
  {
    (send #bit_operation? :positive?)
    (send #bit_operation? :> (int 0))
    (send #bit_operation? :>= (int 1))
    (send #bit_operation? :!= (int 0))
  }
PATTERN

#bit_operation?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/bitwise_predicate.rb', line 68

def_node_matcher :bit_operation?, <<~PATTERN
  (begin
    (send _ :& _))
PATTERN

#nobits?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/bitwise_predicate.rb', line 60

def_node_matcher :nobits?, <<~PATTERN
  {
    (send #bit_operation? :zero?)
    (send #bit_operation? :== (int 0))
  }
PATTERN

#on_send(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/bitwise_predicate.rb', line 73

def on_send(node)
  return unless node.receiver&.begin_type?
  return unless (preferred_method = preferred_method(node))

  bit_operation = node.receiver.children.first
  lhs, _operator, rhs = *bit_operation
  preferred = "#{lhs.source}.#{preferred_method}(#{rhs.source})"

  add_offense(node, message: format(MSG, preferred: preferred)) do |corrector|
    corrector.replace(node, preferred)
  end
end

#preferred_method(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/bitwise_predicate.rb', line 88

def preferred_method(node)
  if anybits?(node)
    'anybits?'
  elsif allbits?(node)
    'allbits?'
  elsif nobits?(node)
    'nobits?'
  end
end