リポジトリ内で指定した単語が書かれた時期を調べる

commit-dates-for-word-of-repository.rb

require 'shellwords'

class AnnotateLine
  attr_reader :content, :meta
  def initialize
    @meta = {}
    @content = nil
  end

  def add_line line
    line.chomp!
    if line =~ /^\t/
      @content = line.gsub /^\t/, ''
    else
      parsed = line.match /^([^ ]+) (.*)$/
      @meta[parsed[1]] = parsed[2]
    end
  end

  def committer_time
    Time.at @meta['committer-time'].to_i
  end
end

class Finder
  def initialize directory, word
    @directory = directory
    @word = word
  end

  def dates
    annotates.map{|annotate|
      annotate.committer_time
    }.sort
  end

  private

  def annotates
    matched_files = `git --no-pager grep --name-only --cached --word-regexp -I --fixed-strings -e #{ Shellwords.escape(@word)} -- #{Shellwords.escape(@directory)}`
    matched_files.each_line.map{|line|
      path = line.chomp
      annotates_for_file_word File.join(@directory, path), @word
    }.flatten
  end

  def annotates_for_file_word file, word
    annotate = `git annotate --line-porcelain #{file}`
    raw_lines = annotate.split(/\n/)
    lines = []
    annotate = AnnotateLine.new
    while raw_lines.length > 0
      annotate.add_line raw_lines.shift
      if annotate.content
        lines << annotate
        annotate = AnnotateLine.new
      end
    end
    lines.select{|line|
      line.content.include? word
    }
  end
end

word, directory = *ARGV

unless word and directory
  warn "usage: ruby commit-dates-for-word-of-repository.rb WORD REPOSITORY"
  exit 1
end

Dir.chdir directory

finder = Finder.new(directory, word)
finder.dates.each{|date|
  puts date
}