Class: Namelab::ListRef

Inherits:
Object
  • Object
show all
Defined in:
lib/namelab/list_ref.rb

Constant Summary collapse

NORMALIZED_FMT = 
"%1$*2$s"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io_proc) ⇒ ListRef

Returns a new instance of ListRef.



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# File 'lib/namelab/list_ref.rb', line 9

def initialize(io_proc)
  @proc = io_proc
  sync!
end

Instance Attribute Details

#lines_count ⇒ Object (readonly)

Returns the value of attribute lines_count.



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# File 'lib/namelab/list_ref.rb', line 7

def lines_count
  @lines_count
end

#proc ⇒ Object (readonly)

Returns the value of attribute proc.



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# File 'lib/namelab/list_ref.rb', line 7

def proc
  @proc
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 36

def close
  @io&.close
  if defined?(@_tmp)
    File.unlink(@_tmp)
    remove_instance_variable(:@_tmp)
  end
  remove_instance_variable(:@io)
end

#each_line(&block) ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 20

def each_line(&block)
  return to_enum(:each_line) unless block_given?
  io.each_line(chomp: true, &block)
end

#filter(&block) ⇒ Object

:yields:



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# File 'lib/namelab/list_ref.rb', line 53

def filter(&block) # :yields:
  @filter = block.to_proc
  self
end

#filtered_sample ⇒ Object

:yields:



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# File 'lib/namelab/list_ref.rb', line 68

def filtered_sample # :yields:
  result = nil
  while result.nil?
    value = sample(false)
    redo unless yield(value)
    result = value
  end
  result
end

#get(lineno) ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 78

def get(lineno)
  offset = lineno * @sample_size
  begin
    @io.pread(@sample_size, offset)
  rescue EOFError
    offset -= @sample_size
    retry
  end
end

#io ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 25

def io
  @io ||= @proc[]
end

#lines(enum: true, &block) ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 14

def lines(enum: true, &block)
  enum ? each_line(&block) : block.(each_line)
ensure
  rewind
end

#rewind ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 45

def rewind
  @io&.rewind
end

#sample(filter = true) ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 58

def sample(filter = true)
  if filter && defined?(@filter)
    proc = @filter
    remove_instance_variable(:@filter)
    filtered_sample(&proc)
  else
    get(sample_lineno).strip
  end
end

#sample_lineno ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 49

def sample_lineno
  rand(lines_count)
end

#sync! ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 90

def sync!
  remove_instance_variable(:@_tmp) if defined?(@_tmp)
  tempfile = Tempfile.new(File.basename(io.path))
  lines enum: false do |enum|
    @sample_size = enum.max_by(&:length).length
    rewind
    lines_count = 0
    enum.each do |v|
      tempfile.printf(NORMALIZED_FMT, v, -@sample_size)
      lines_count += 1
    end
    @lines_count = lines_count
  end
  tempfile.rewind
  close
  @_tmp = tempfile.path
  @io = tempfile.to_io
  at_exit { close }
end

#with_io ⇒ Object 



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# File 'lib/namelab/list_ref.rb', line 29

def with_io
  io
  yield(self)
ensure
  close
end