Module: PPipe::Reader

Includes:
Log, Timeout
Included in:
PPipe, Methods
Defined in:
lib/parallelpipes.rb

Overview

PPipe requires a method of reading pipes that will not block even if the pipe is empty, is at eof, or has not been written to yet. configure_reader dynamically defines this method, which is called read_pipe

Reader is included in PPipe. It can also be included independently in any class

Instance Attribute Summary

Attributes included from Log

#verbosity

Instance Method Summary collapse

Methods included from Log

clean_up, io=, #log, log_file, log_file=

Instance Method Details

#configure_reader ⇒ Object

The best way of defining Reader#read_pipe is operating system dependent. Work out which is the best way and then define the method read_pipe to be this method.



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# File 'lib/parallelpipes.rb', line 967

def configure_reader
	@verbosity ||= 0  # for logging purposes
	pipes = [nil, IO.pipe]

	pipe = IO.pipe
	
	pipes[1][1].sync = true
	pipe[1].sync = true

	my_pipes = []

	pid = Kernel.fork
	
	if pid
		pipe[1].close
		my_pipes.push pipe[0]
		pipes[1][0].close
		pipes[1] = pipes[1][1]
	# 			pipes[1].puts
	# 			sleep 0.002
		log 'v8', 'sending pears'
		pipes[1].sync = true
		pipes[1].print('pears' + "\n")
	# 			cmd = [2].pack("S")
	# 			pipes[1].ioctl(5, cmd)
	# 			sleep 1
		log 'v8',  'waiting for apples...'
		method = determine_read(my_pipes[0], "apples\nare\nnice\n")
		log 'v8', method
		self.class.send(:alias_method, :read_pipe, method)
		self.class.send(:alias_method, :get_line, method + :_get_line)
		my_pipes[0].close
		pipes[1].close
		return method
	else
		pipes[1][1].close
		my_pipes.push pipes[1][0]
		pipes[1] = nil
		pipe[0].close
		pipes[0] = pipe[1]
		pipes[0].sync = true
		log 'v8', pipes.inspect
	# 			sleep 0.5
		log 'v8', 'waiting for pears'
		log 'v8', determine_read(my_pipes[0], "pears\n")
		
			
		log 'v8', 'sending apples'
		pipes[0].print("apples\nare\nnice" + "\n")
		pipes[0].flush
		exit
	end
end

#get_line(pipe, sep = $/) ⇒ Object

Get the next line from the pipe. Return nil if the pipe is empty or at eof. Blocks if the pipe is not empty but does not contain a complete line.



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# File 'lib/parallelpipes.rb', line 828

def get_line(pipe, sep = $/)
end

#read_pipe(pipe) ⇒ Object

Read all the contents of the pipe. Return nil if the pipe is empty. Never, ever, ever, ever block!



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# File 'lib/parallelpipes.rb', line 823

def read_pipe(pipe)
end