#!/usr/bin/env python

import os
import select
import six
import empty
import dbg

def no_buffering(f):
	if six.PY2:
		return os.fdopen(f.fileno(), 'r', 0)
	return os.fdopen(f.fileno(), 'rb', buffering=0)

readable = lambda f, tmout=0: select.select([f], [], [], tmout)[0] == [f]

def read1(f, tmout=0):
	if readable(f, tmout):
		return f.read(1) # EOF is b'' or ''
	return None # timeout

def reader_new(f, tmout=0, to_str=True, no_buf=False):
	# return '' is EOF
	# return None is timeout

	if no_buf:
		f = no_buffering(f)

	e = empty.new()

	readable_ = lambda : readable(f, tmout)
	e.readable = readable_

	e.type = None

	def read1_():
		b = read1(f, tmout)
		if b == None:
			return None # timeout
		if e.type == None or e.type != type(b):
			e.type = type(b)
		if to_str and  e.type == bytes:
			return b.decode() # EOF is ''
		return b # EOF is '' or b''
	e.read1 = read1_

	def read():
		lst = []
		r1 = None
		while True:
			r1 = read1_()
			if not r1: # None is timeout , '' or b'' is EOF
				break
			lst.append(r1)

		if not lst:
			if r1 == None: # timeout
				return None
			r0 = '' if e.type in (str, None) else b''
			return r0

		r0 = '' if type(lst[0]) == str else b''
		return r0.join(lst)

	def read_to(k): # to_str=True only
		buf = ''
		while True:
			r1 = read1_()
			if not r1: # None is timeout , '' is EOF
				return buf if buf else r1
			buf += r1
			if buf.endswith(k):
				break
		return buf

	e.buf = ''

	def pop_buf():
		(r, e.buf) = (e.buf, '')
		return r

	def readline(): # to_str=True only
		while True:
			c = read1_()
			if c == None: # timeout
				break
			if c == '': # EOF
				return pop_buf()
			e.buf += c
			if c in ('\n', '\r'):
				return pop_buf() # '\n', '\r' contained
		return None # timeout

	e.lines = []

	def pop_lines():
		(r, e.lines) = (e.lines, [])
		return r

	def readlines(): # to_str=True only
		# delim is "\n" line
		# return list of str
		# return [] is EOF
		# return None is timeout

		while True:
			s = readline()
			if s == None: # timeout
				break
			if s == '': # EOF
				return pop_lines()
			e.lines.append(s)
			if s == '\n': # delim
				return pop_lines() # delim contained
		return None # timeout

	return empty.to_attr( e, locals() )


if __name__ == "__main__":
	import cmd_ut
	import yaml

	cmd = 'ls ; echo "" ; ls ; echo ""'
	proc = cmd_ut.proc_new(cmd, stdout=cmd_ut.PIPE)
	f = proc.get_stdout()
	rdr = reader_new(f)

	while True:
		lst = rdr.readlines()
		if lst == []:
			break
		if lst:
			for s in lst:
				dbg.out(s, '')
# EOF