Method: PathSpec::GitIgnoreSpec#initialize

Defined in:
lib/pathspec/gitignorespec.rb

#initialize(original_pattern) ⇒ GitIgnoreSpec

rubocop:disable Metrics/CyclomaticComplexity



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# File 'lib/pathspec/gitignorespec.rb', line 10

def initialize(original_pattern) # rubocop:disable Metrics/CyclomaticComplexity
  pattern = original_pattern.strip unless original_pattern.nil?

  # A pattern starting with a hash ('#') serves as a comment
  # (neither includes nor excludes files). Escape the hash with a
  # back-slash to match a literal hash (i.e., '\#').
  if pattern.start_with?('#')
    @regex = nil
    @inclusive = nil

    # A blank pattern is a null-operation (neither includes nor
    # excludes files).
  elsif pattern.empty? # rubocop:disable Lint/DuplicateBranch
    @regex = nil
    @inclusive = nil

    # Patterns containing three or more consecutive stars are invalid and
    # will be ignored.
  elsif /\*\*\*+/.match?(pattern) # rubocop:disable Lint/DuplicateBranch
    @regex = nil
    @inclusive = nil

    # EDGE CASE: According to git check-ignore (v2.4.1)), a single '/'
    # does not match any file
  elsif pattern == '/' # rubocop:disable Lint/DuplicateBranch
    @regex = nil
    @inclusive = nil

    # We have a valid pattern!
  else
    # A pattern starting with an exclamation mark ('!') negates the
    # pattern (exclude instead of include). Escape the exclamation
    # mark with a back-slash to match a literal exclamation mark
    # (i.e., '\!').
    if pattern.start_with?('!')
      @inclusive = false
      # Remove leading exclamation mark.
      pattern = pattern[1..]
    else
      @inclusive = true
    end

    # Remove leading back-slash escape for escaped hash ('#') or
    # exclamation mark ('!').
    pattern = pattern[1..] if pattern.start_with?('\\')

    # Split pattern into segments. -1 to allow trailing slashes.
    pattern_segs = pattern.split('/', -1)

    # Normalize pattern to make processing easier.

    # A pattern beginning with a slash ('/') will only match paths
    # directly on the root directory instead of any descendant
    # paths. So, remove empty first segment to make pattern relative
    # to root.
    if pattern_segs[0].empty?
      pattern_segs.shift
    elsif pattern_segs.length == 1 ||
          pattern_segs.length == 2 && pattern_segs[-1].empty?
      # A pattern without a beginning slash ('/') will match any
      # descendant path. This is equivilent to "**/{pattern}". So,
      # prepend with double-asterisks to make pattern relative to
      # root.
      # EDGE CASE: This also holds for a single pattern with a
      # trailing slash (e.g. dir/).
      pattern_segs.insert(0, '**') if pattern_segs[0] != '**'
    end

    # A pattern ending with a slash ('/') will match all descendant
    # paths of if it is a directory but not if it is a regular file.
    # This is equivilent to "{pattern}/**". So, set last segment to
    # double asterisks to include all descendants.
    pattern_segs[-1] = '**' if pattern_segs[-1].empty? && pattern_segs.length > 1

    # Handle platforms with backslash separated paths
    path_sep = if File::SEPARATOR == '\\'
                 '\\\\'
               else
                 '/'
               end

    # Build regular expression from pattern.
    regex = +'^'
    need_slash = false
    regex_end = pattern_segs.size - 1
    pattern_segs.each_index do |i|
      seg = pattern_segs[i]

      case seg
      when '**'
        # A pattern consisting solely of double-asterisks ('**')
        # will match every path.
        if i == 0 && i == regex_end
          regex.concat('.+')

          # A normalized pattern beginning with double-asterisks
          # ('**') will match any leading path segments.
        elsif i == 0
          regex.concat("(?:.+#{path_sep})?")
          need_slash = false

          # A normalized pattern ending with double-asterisks ('**')
          # will match any trailing path segments.
        elsif i == regex_end
          regex.concat("#{path_sep}.*")

          # A pattern with inner double-asterisks ('**') will match
          # multiple (or zero) inner path segments.
        else
          regex.concat("(?:#{path_sep}.+)?")
          need_slash = true
        end

        # Match single path segment.
      when '*'
        regex.concat(path_sep) if need_slash

        regex.concat("[^#{path_sep}]+")
        need_slash = true

      else
        # Match segment glob pattern.
        regex.concat(path_sep) if need_slash

        regex.concat(translate_segment_glob(seg))

        if i == regex_end && @inclusive
          # A pattern ending without a slash ('/') will match a file
          # or a directory (with paths underneath it).
          # e.g. foo matches: foo, foo/bar, foo/bar/baz, etc.
          # EDGE CASE: However, this does not hold for exclusion cases
          # according to `git check-ignore` (v2.4.1).
          regex.concat("(?:#{path_sep}.*)?")
        end

        need_slash = true
      end
    end

    regex.concat('$')
    super(regex)

    # Copy original pattern
    @pattern = original_pattern.dup
  end
end