FuseFSのサンプルプログラム あらかじめ $sudo apt-get install fuse-devel libfuse-dev しといてください(Ubuntuの場合)

fusefstest.rb

#試すときは
#sudo ruby fusefstest.rb <mountpoint>
#ls, mkdir, rmdir, cat, mv, vi, nanoとかは多分使える
#終わったら sudo umount <mountpoint>

#エラーのときにどうすればいいかわからない
#raise Errno::E*** は意味無さそう

#タイムスタンプやパーミッションの扱い方はわからない
#今のところtouchやchmod, chownなどのコマンドは使えない

require 'fusefs'

class Entry
  @child
  attr_reader :is_dir
  attr_reader :is_file
  attr_reader :name
  attr_accessor :data

  def initialize(name, is_file)
    @child = []
    @name = name
    if is_file
      @is_file = true
      @is_dir = false
    else
      @is_file = false
      @is_dir = true
    end
  end

  def find_child(name)
    return nil if @is_file
    for c in @child do
      if c.name == name
        return c
      end
    end
    return nil
  end

  def mkdir(name)
    return nil if @is_file
    c = Entry.new(name, false)
    @child << c
    return c
  end

  def create_file(name)
    return nil if @is_file
    c =  Entry.new(name, true)
    @child << c
    return c
  end

  def contents
    @child.map{|c| c.name}
  end

  def rename(name)
    @name = name
  end

  def delete(name)
    @child.delete_if{|c| c.name == name && c.is_file}
  end

  def rmdir(name)
    @child.delete_if{|c| c.name == name && c.is_dir}
  end
end

#http://rubydoc.info/github/lwoggardner/rfusefs/FuseFS/API 参照

class HelloDir
  @root

  def initialize
    @root = Entry.new(nil, false)
    @root.mkdir('dir')
    @root.create_file('hello.txt').data = "Hello, world!\n"
  end

  def get_entry(path)
    if path == '/'
      return @root
    end
    e = @root
    while e
      i = path.index('/', 1)
      if i == nil
        e = e.find_child(path[1..-1])
        break
      end
      e = e.find_child(path[1..(i-1)])
      path = path[i..-1]
    end
    return e
  end

  def contents(path)
    e = get_entry(path)
    return e.contents if e
  end

  def directory?(path)
    e = get_entry(path)
    return e.is_dir if e
  end

  def file?(path)
    e = get_entry(path)
    return e.is_file if e
  end

  def read_file(path)
    e = get_entry(path)
    return e.data if e && e.is_file
  end

  def size(path)
    read_file(path).size
  end

  def can_write?(path)
    e = get_entry(File.dirname(path))
    return e ? e.is_dir : false
  end

#ファイルが存在しないときは新しく作成して書き込む
  def write_to(path, str)
    e = get_entry(path)
    p = get_entry(File.dirname(path))
    e = p.create_file(File.basename(path)) if e == nil
    e.data = str if e && e.is_file
  end

  def can_mkdir?(path)
    e = get_entry(File.dirname(path))
    return e ? e.is_dir : false
  end

  def mkdir(path)
    e = get_entry(File.dirname(path))
    e.mkdir(File.basename(path)) if e
  end

#定義しても呼び出されていないっぽい
#  def touch(path, modtime)
#    p modtime
#  end
#
#  def times(path)
#    puts "times(#{path})"
#    return [1,2,3]
#  end

  def rename(from_path, to_path)
    return false if File.dirname(from_path) != File.dirname(to_path)
    e = get_entry(from_path)
    e.rename(File.basename(to_path)) if e
    return e
  end

  def can_delete?(path)
    e = get_entry(path)
    return e && e.is_file
  end

  def delete(path)
    e = get_entry(File.dirname(path))
    e.delete(File.basename(path)) if e
  end

  def can_rmdir?(path)
    e = get_entry(path)
    return e && e.is_dir
  end

  def rmdir(path)
    e = get_entry(File.dirname(path))
    e.rmdir(File.basename(path)) if e
  end
end

hellodir = HelloDir.new
FuseFS.set_root( hellodir )

FuseFS.mount_under ARGV.shift
FuseFS.run