Class: Chitin::Pipe

Inherits:
Object show all
Includes:
Runnable
Defined in:
lib/chitin/commands/pipe.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Runnable

#>, #[]

Constructor Details

#initialize(*parts) ⇒ Pipe

Returns a new instance of Pipe.



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# File 'lib/chitin/commands/pipe.rb', line 8

def initialize(*parts)
  @parts = parts
  
  link_all
end

Instance Attribute Details

#parts ⇒ Object

Returns the value of attribute parts.



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# File 'lib/chitin/commands/pipe.rb', line 5

def parts
  @parts
end

#pids ⇒ Object

Returns the value of attribute pids.



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# File 'lib/chitin/commands/pipe.rb', line 6

def pids
  @pids
end

Instance Method Details

#err ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 93

def err
  @parts.last[:err]
end

#err=(other) ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 96

def err=(other); @parts.last[:set_err, other]; end

#in ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 83

def in
  @parts.first[:in]
end

#in=(other) ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 86

def in=(other); @parts.first[:set_in, other]; end

#link(left, right) ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 25

def link(left, right)
  # The pipe that we use to connect the dots
  r, w = IO.pipe
  
  # since left will want to write to STDOUT, we have to give it
  # something else it can write to.
  left > w

  # same thing for right, but with reading
  r > right
  
  # right will try to read from r until w is closed.
  # when w is closed, right will finish processing.
  # if we don't close this, right will never return
  w.close
  r.close # and we close r so that we don't have any open useless handles
end

#link_all ⇒ Object

link everything together



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# File 'lib/chitin/commands/pipe.rb', line 15

def link_all
  # move from left to right through the list
  # link the left one to the right one
  parts[1..-1].inject parts.first do |left, right|
    link left, right
    # return this, and shift the whole process one to the right
    right
  end
end

#out ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 88

def out
  @parts.last[:out]
end

#out=(other) ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 91

def out=(other); @parts.last[:set_out, other]; end

#raw_run ⇒ Object

Run them all but let the last run return its value



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# File 'lib/chitin/commands/pipe.rb', line 52

def raw_run
  parts[0..-2].each {|part| part[:run] }
  result = parts.last[:raw_run]
  reset
  
  result
end

#reset ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 66

def reset
  parts.map {|part| part[:reset] }
  link_all # we have to refresh the pipes connecting everything
  
  self
end

#returning ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 102

def returning
  if [StringMethod, Proc].include?(@parts.last[:class])
    :ruby
  else
    :io
  end
end

#run ⇒ Object

Like raw_run, but meant to be used in chaining.



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# File 'lib/chitin/commands/pipe.rb', line 44

def run
  parts.each {|part| part[:run] }
  reset
  
  self
end

#to_s ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 98

def to_s
  "#{self.in} > #{parts.map {|p| p[:to_s] }.join ' | '} > #{self.out}"
end

#wait ⇒ Object 



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# File 'lib/chitin/commands/pipe.rb', line 60

def wait
  parts.each {|part| part[:wait] }
  
  self
end

#|(other) ⇒ Object Also known as: <=> 



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# File 'lib/chitin/commands/pipe.rb', line 73

def |(other)
  raise "#{other.class} needs to include Runnable" unless Runnable === other
  
  link parts.last, other
  parts << other
  
  self
end