regtest/Printer.py

# Printer.py
#
# Copyright (C) 2012 Carlos Garcia Campos <carlosgc@gnome.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
from __future__ import absolute_import, division, print_function

import sys
from Config import Config

from threading import RLock


_instance = None


class Printer:
    def __init__(self):
        global _instance
        if _instance is not None:
            raise RuntimeError('Printer must not be instantiated more than '
                               'once. Use the get_printer() function instead.')

        self._verbose = Config().verbose
        self._stream = sys.stdout
        self._rewrite = self._stream.isatty() and not self._verbose
        self._current_line_len = 0
        self._blocked = 0

        self._lock = RLock()

        _instance = self

    def _erase_current_line(self):
        if not self._current_line_len:
            return

        line_len = self._current_line_len
        self._stream.write('\b' * line_len + ' ' * line_len + '\b' * line_len)
        self._current_line_len = 0

    def _ensure_new_line(self, msg):
        if not msg.endswith('\n'):
            msg += '\n'
        return msg

    def _print(self, msg):
        self._stream.write(msg)
        self._stream.flush()

    def printout(self, msg):
        if not self._rewrite:
            self.printout_ln(msg)

        with self._lock:
            if self._blocked > 0:
                return
            self._erase_current_line()
            self._print(msg)
            self._current_line_len = len(msg[msg.rfind('\n') + 1:])

    def printout_ln(self, msg=''):
        with self._lock:
            if self._blocked > 0:
                return
            self._erase_current_line()
            self._print(self._ensure_new_line(msg))

    def printerr(self, msg):
        with self._lock:
            if self._blocked > 0:
                return
            sys.stderr.write(self._ensure_new_line(msg))
            sys.stderr.flush()

    def print_test_result(self, doc_path, backend_name, n_test, total_tests, msg):
        self.printout("[%d/%d] %s (%s): %s" % (n_test, total_tests, doc_path, backend_name, msg))

    def print_test_result_ln(self, doc_path, backend_name, n_test, total_tests, msg):
        self.printout_ln("[%d/%d] %s (%s): %s" % (n_test, total_tests, doc_path, backend_name, msg))

    def print_default(self, msg):
        if self._verbose:
            self.printout_ln(msg)

    def block(self):
        with self._lock:
            self._blocked += 1

    def unblock(self):
        with self._lock:
            self._blocked -= 1


def get_printer():
    if _instance is None:
        Printer()
    return _instance