rb/support/generated_note.rb

# frozen_string_literal: true

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# to you under the Apache License, Version 2.0 (the
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#
#   http://www.apache.org/licenses/LICENSE-2.0
#
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# Shared generated-file marker text for Ruby generators — see scripts/generated_note_template.txt.
module GeneratedNote
  def self.runfiles
    @runfiles ||= begin
      require 'bazel/runfiles'
      Bazel::Runfiles.create
    end
  end

  # Resolves a Bazel rlocation key to a real path. Fail loud: a generator has no non-Bazel
  # fallback, and rlocation returns nil when not running under a runfiles tree.
  def self.rlocation(key)
    runfiles.rlocation(key) || raise("Could not resolve runfile #{key.inspect}")
  end

  # Renders the standard two-line generated-file marker in the given comment style.
  def self.render(comment_prefix, generator, command)
    template = File.read(rlocation('_main/scripts/generated_note_template.txt'))
    text = template.sub('{generator}', generator).sub('{command}', command)
    text.rstrip.split("\n").map { |line| "#{comment_prefix} #{line}" }.join("\n")
  end
end