# File lib/cache.rb, line 29
  def initialize(repository=REPOSITORY, max_size=MAX_SIZE)
    @repository = Pathname.new(repository)
    @max_size = check_max_size(max_size)
    create
  end

# File lib/cache.rb, line 134
  def [](index)
    @atime[index]
  end

# File lib/cache.rb, line 54
  def clear
    @repository.each_entry do |p|
      (@repository + p).delete unless p.to_s =~ /^\./
    end
    @size = 0
    @atime.clear
  end

# File lib/cache.rb, line 38
  def create
    @size = 0
    @atime = []
    if @repository.directory?
      @repository.each_entry do |p|
        next if p.to_s =~ /^\./
        full_p = @repository + p
        @atime << full_p
        @size += full_p.size
      end
      @atime.sort! { |a, b| a.atime <=> b.atime }
    else
      @repository.mkdir
    end
  end

# File lib/cache.rb, line 130
  def each
    @atime.each { |p| yield(p) }
  end

# File lib/cache.rb, line 118
  def export(md5sum, dst_filename)
    p = @repository + md5sum.to_s
    FileUtils.copy_entry(p, dst_filename)
    update_entry(p)
    p
  end

# File lib/cache.rb, line 109
  def import(filename)
    p = nil
    pathname = filename.to_path
    pathname.open do |f|
      p = write(pathname.stat.mode) { f.eof? ? nil : f.read(BLOCK_SIZE) }
    end
    p
  end

# File lib/cache.rb, line 138
  def max_size=(max_size)
    @max_size = check_max_size(max_size)
    adjust_size
  end

# File lib/cache.rb, line 143
  def nb_files
    @atime.size
  end

# File lib/cache.rb, line 67
  def open(md5sum=nil, mode='r', perm=0644, &block)
    case mode
    when 'r': read(md5sum, &block)
    when 'w': write(perm, &block)
    else
      raise(ArgumentError, "`#{mode}' - bad mode")
    end
  end

# File lib/cache.rb, line 125
  def present?(md5sum)
    p = @repository + md5sum.to_s
    p.exist? ? p : nil;
  end

# File lib/cache.rb, line 76
  def read(md5sum, &block)
    p = @repository + md5sum.to_s
    p.open('r', &block)
    @atime.delete(p)
    @atime << p
    p
  end

# File lib/cache.rb, line 62
  def recreate
    clear
    create
  end

# File lib/cache.rb, line 84
  def write(perm=0644, &block)
    TempPath.new('cache_file') do |tmp|
      md5 = Digest::MD5.new
      new_size = 0
      tmp.open('w') do |out|
        while (str = block[])
          out.write(str)
          md5 << str
          new_size += str.size
        end
      end
      p = @repository + md5.to_s
      if p.exist?
        @atime.delete(p)
      else
        @size += new_size
      end
      FileUtils.move(tmp.to_s, p.to_s)
      p.chmod(perm)
      @atime << p
      adjust_size
      p
    end
  end

# File lib/cache.rb, line 148
  def adjust_size
    while @size > @max_size
      p = @atime.shift
      @size -= p.size
      p.delete
    end
    @size
  end

# File lib/cache.rb, line 158
  def check_max_size(max_size)
    unless max_size > 0
      raise(ArgumentError, "`#{max_size}' - bad cache maximum size")
    end
    max_size
  end