openthread/tools/spinel-cli/spinel/stream.py

#!/usr/bin/python
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"""
Module providing a generic stream interface.
Also includes adapter implementations for serial, socket, and pipes.
"""

import sys
import logging
import traceback

import subprocess
import socket
import serial

import spinel.util
import spinel.config as CONFIG


class IStream(object):
    """ Abstract base class for a generic Stream Interface. """

    def read(self, size):
        """ Read an array of byte integers of the given size from the stream. """
        pass

    def write(self, data):
        """ Write the given packed data to the stream. """
        pass

    def close(self):
        """ Close the stream cleanly as needed. """
        pass


class StreamSerial(IStream):
    """ An IStream interface implementation for serial devices. """

    def __init__(self, dev, baudrate=115200):
        try:
            self.serial = serial.Serial(dev, baudrate)
        except:
            logging.error("Couldn't open " + dev)
            print traceback.format_exc()

    def write(self, data):
        self.serial.write(data)
        if CONFIG.DEBUG_STREAM_TX:
            logging.debug("TX Raw: " + str(map(spinel.util.hexify_chr, data)))

    def read(self, size=1):
        pkt = self.serial.read(size)
        if CONFIG.DEBUG_STREAM_RX:
            logging.debug("RX Raw: " + str(map(spinel.util.hexify_chr, pkt)))
        return map(ord, pkt)[0]


class StreamSocket(IStream):
    """ An IStream interface implementation over an internet socket. """

    def __init__(self, hostname, port):
        # Open socket
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect((hostname, port))

    def write(self, data):
        self.sock.send(data)
        if CONFIG.DEBUG_STREAM_TX:
            logging.debug("TX Raw: " + str(map(spinel.util.hexify_chr, data)))

    def read(self, size=1):
        pkt = self.sock.recv(size)
        if CONFIG.DEBUG_STREAM_RX:
            logging.debug("RX Raw: " + str(map(spinel.util.hexify_chr, pkt)))
        return map(ord, pkt)[0]


class StreamPipe(IStream):
    """ An IStream interface implementation to stdin/out of a piped process. """

    def __init__(self, filename):
        """ Create a stream object from a piped system call """
        try:
            self.pipe = subprocess.Popen(filename, shell=True,
                                         stdin=subprocess.PIPE,
                                         stdout=subprocess.PIPE,
                                         stderr=sys.stdout.fileno())
        except:
            logging.error("Couldn't open " + filename)
            print traceback.format_exc()

    def write(self, data):
        if CONFIG.DEBUG_STREAM_TX:
            logging.debug("TX Raw: (%d) %s",
                          len(data), spinel.util.hexify_bytes(data))
        self.pipe.stdin.write(data)

    def read(self, size=1):
        """ Blocking read on stream object """
        pkt = self.pipe.stdout.read(size)
        if CONFIG.DEBUG_STREAM_RX:
            logging.debug("RX Raw: " + str(map(spinel.util.hexify_chr, pkt)))
        return map(ord, pkt)[0]

    def close(self):
        if self.pipe:
            self.pipe.kill()
            self.pipe = None


def StreamOpen(stream_type, descriptor, verbose=True):
    """
    Factory function that creates and opens a stream connection.

    stream_type:
        'u' = uart (/dev/tty#)
        's' = socket (port #)
        'p' = pipe (stdin/stdout)

    descriptor:
        uart - filename of device (/dev/tty#)
        socket - port to open connection to on localhost
        pipe - filename of command to execute and bind via stdin/stdout
    """

    if stream_type == 'p':
        if verbose:
            print "Opening pipe to " + str(descriptor)
        return StreamPipe(descriptor)

    elif stream_type == 's':
        port = int(descriptor)
        hostname = "localhost"
        if verbose:
            print "Opening socket to " + hostname + ":" + str(port)
        return StreamSocket(hostname, port)

    elif stream_type == 'u':
        dev = str(descriptor)
        baudrate = 115200
        if verbose:
            print "Opening serial to " + dev + " @ " + str(baudrate)
        return StreamSerial(dev, baudrate)

    else:
        return None