repo.rb

def commits(&block)
  queue = self.sha_list
  self.thread_count.times.map {
    Thread.new do
      while sha = mutex.synchronize { queue.shift }
        hash = fetch_sha(sha)
        commit = Commit.new(hash, repo_name, username)
        mutex.synchronize { block.call commit }
      end
    end
  }.each(&:join)
end

def sha_list
    queue = self.generate_sha_windows
    result = []
    self.thread_count.times.map {
      Thread.new do
        while window = mutex.synchronize { queue.shift }
          since_time, until_time = window
          list = commits_window(since_time, until_time)
          mutex.synchronize { result.concat list }
        end
      end
    }.each(&:join)
  end
  result
end