# Copyright The IETF Trust 2010-2020, All Rights Reserved
# -*- coding: utf-8 -*-


# Simplified interface to os.popen3()

def pipe(cmd, str=None):
    from subprocess import Popen, PIPE
    bufsize = 4096
    MAX = 65536*16

    if str and len(str) > 4096:                 # XXX: Hardcoded Linux 2.4, 2.6 pipe buffer size
        bufsize = len(str)

    with Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, bufsize=bufsize, shell=True) as pipe:
        if not str is None:
            pipe.stdin.write(str)
            pipe.stdin.close()

        out = b""
        err = b""
        while True:
            str = pipe.stdout.read()
            if str:
                out += str
            code = pipe.poll()
            if code != None:
                err = pipe.stderr.read()
                break
            if len(out) >= MAX:
                err = "Output exceeds %s bytes and has been truncated" % MAX
                break

    return (code, out, err)