text_log.py

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#!/usr/bin/env python
# -*- Python -*-
# -*- coding: utf-8 -*-

'''rtshell

Copyright (C) 2009-2014
    Geoffrey Biggs
    RT-Synthesis Research Group
    Intelligent Systems Research Institute,
    National Institute of Advanced Industrial Science and Technology (AIST),
    Japan
    All rights reserved.
Licensed under the Eclipse Public License -v 1.0 (EPL)
http://www.opensource.org/licenses/eclipse-1.0.txt

Text-based log.

'''


import copy
import os

import ilog


###############################################################################
## Text-based log object. It only supports writing log files. It relies on
## the data types having suitable __repr__ methods.

class TextLog(ilog.Log):
    def __init__(self, filename='', *args, **kwargs):
        self._is_open = False
        self._fn = filename
        super(TextLog, self).__init__(*args, **kwargs)

    def __str__(self):
        if self._is_open:
            return 'TextLog({0}, {1}) at position {2}.'.format(self._fn,
                    self._mode, self._file.tell())
        else:
            return 'TextLog({0}, {1}).'.format(self._fn, self._mode)

    def write(self, timestamp, data):
        pos = self._file.tell()
        self._file.write('{0}\t{1}\n'.format(timestamp, data))
        self._vb_print('Wrote entry at {0}.'.format(pos))

    def _close(self):
        if not self._is_open:
            return
        self._file.close()
        self._is_open = False
        self._vb_print('Closed file.')

    def _get_cur_pos(self):
        if self._is_open:
            self._vb_print('Current position: {0}'.format(self._file.tell()))
            return self._file.tell()
        else:
            self._vb_print('Current position: file closed.')
            return 0

    def _open(self):
        if self._is_open:
            return
        if self._mode == 'w':
            flags = 'w'
        else:
            raise NotImplementedError
        self._file = open(self._fn, flags)
        self._is_open = True
        self._vb_print('Opened file {0} in mode {1}.'.format(self._fn,
            self._mode))