Class: Magritte::Pipe

Inherits:
Object
  • Object
show all
Defined in:
lib/magritte/pipe.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input, output = nil) ⇒ Pipe

Returns a new instance of Pipe.



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# File 'lib/magritte/pipe.rb', line 11

def initialize(input, output=nil)
  @input  = input
  @output = output
  @line_by_line = false
end

Class Method Details

.from_input_file(infile) ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 17

def self.from_input_file(infile)
  self.from_input_stream(File.open(infile))
end

.from_input_stream(io) ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 21

def self.from_input_stream(io)
  new(BlockStream.new(io))
end

.from_input_string(str) ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 25

def self.from_input_string(str)
  self.from_input_stream((StringIO.new(str)))
end

Instance Method Details

#filtering_with(command) ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 54

def filtering_with(command)
  raise "No output IO is set! Invoke out_to first!" unless @output

  Open3.popen2e(command) do |subproc_input, subproc_output, wait_thr|
    @subproc_output = BlockStream.new(subproc_output)
    @subproc_input  = BlockStream.new(subproc_input)

    clear_buffers

    while true do
      read_ready, write_ready, = select

      read_from_input

      if write_ready
        write_to_subproc
      end

      if read_ready
        read_from_subproc
        write_output
      end

      # We close the input to signal to the sub-process that we are
      # done sending data. It will close its output when processsing
      # is completed. That signals us to stop piping data.
      if ready_to_close?
        @subproc_input.flush
        @subproc_input.close
      end

      break if @subproc_output.closed?
    end

    raise Errno::EPIPE.new("sub-process dirty exit!") unless wait_thr.value == 0
  end
end

#line_by_line ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 49

def line_by_line
  @line_by_line = true
  self
end

#out_to(io = nil, &block) ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 29

def out_to(io=nil, &block)
  unless block_given?
    @output = BlockStream.new(io)
    return self
  end

  proc = Proc.new(&block)
  if @line_by_line
    @output = LineBufferOutputStream.new(proc, @record_separator || "\n")
  else
    @output = ProcOutputStream.new(proc)
  end

  self
end

#separated_by(record_separator) ⇒ Object 



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# File 'lib/magritte/pipe.rb', line 45

def separated_by(record_separator)
  @record_separator = record_separator
end