class Geminabox::DiskCache

def cache(key)
  key = Digest::MD5.hexdigest(key)
  read(key) || write(key, yield)
end

def ensure_dir_exists!
  FileUtils.mkdir_p(root_path)
end

def flush
  FileUtils.rm_rf(root_path)
  ensure_dir_exists!
end

def initialize(root_path)
  @root_path = root_path
  ensure_dir_exists!
end

def read(key)
  path = File.join(root_path, key)
  File.read(path) if File.exists?(path)
end

def write(key, value)
  path = File.join(root_path, key)
  File.open(path, 'wb'){|f|
    f << value
  }
  value
end