shard-ameba/src/ameba/inline_comments.cr

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Crystal
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module Ameba
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# A module that utilizes inline comments parsing and processing logic.
module InlineComments
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COMMENT_DIRECTIVE_REGEX =
/# ameba:(?<action>\w+) (?<rules>\w+(?:\/\w+)?(?:,? \w+(?:\/\w+)?)*)/
# Available actions in the inline comments
enum Action
Disable
Enable
end
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# Returns `true` if current location is disabled for a particular rule,
# `false` otherwise.
#
# Location is disabled in two cases:
# 1. The line of the location ends with a comment directive.
# 2. The line above the location is a comment directive.
#
# For example, here are two examples of disabled location:
#
# ```
# # ameba:disable Style/LargeNumbers
# Time.epoch(1483859302)
#
# Time.epoch(1483859302) # ameba:disable Style/LargeNumbers
# ```
#
# But here are examples which are not considered as disabled location:
#
# ```
# # ameba:disable Style/LargeNumbers
# #
# Time.epoch(1483859302)
#
# if use_epoch? # ameba:disable Style/LargeNumbers
# Time.epoch(1483859302)
# end
# ```
def location_disabled?(location : Crystal::Location?, rule)
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return false if rule.name.in?(Rule::SPECIAL)
return false unless line_number = location.try &.line_number.try &.- 1
return false unless line = lines[line_number]?
line_disabled?(line, rule) ||
(line_number > 0 &&
(prev_line = lines[line_number - 1]) &&
comment?(prev_line) &&
line_disabled?(prev_line, rule))
end
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# Parses inline comment directive. Returns a tuple that consists of
# an action and parsed rules if directive found, nil otherwise.
#
# ```
# line = "# ameba:disable Rule1, Rule2"
# directive = parse_inline_directive(line)
# directive[:action] # => "disable"
# directive[:rules] # => ["Rule1", "Rule2"]
# ```
#
# It ignores the directive if it is commented out.
#
# ```
# line = "# # ameba:disable Rule1, Rule2"
# parse_inline_directive(line) # => nil
# ```
def parse_inline_directive(line)
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return unless directive = COMMENT_DIRECTIVE_REGEX.match(line)
return if commented_out?(line.gsub(directive[0], ""))
{
action: directive["action"],
rules: directive["rules"].split(/[\s,]/, remove_empty: true),
}
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end
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# Returns `true` if the line at the given `line_number` is a comment.
def comment?(line_number : Int32)
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return unless line = lines[line_number]?
comment?(line)
end
private def comment?(line : String)
line.lstrip.starts_with? '#'
end
private def line_disabled?(line, rule)
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return false unless directive = parse_inline_directive(line)
return false unless Action.parse?(directive[:action]).try(&.disable?)
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rules = directive[:rules]
rules.includes?(rule.name) || rules.includes?(rule.group)
end
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private def commented_out?(line)
commented = false
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lexer = Crystal::Lexer.new(line).tap(&.comments_enabled = true)
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Tokenizer.new(lexer).run do |token|
commented = true if token.type.comment?
end
commented
end
end
end