Minecraft-Overviewer/overviewer_core/observer.py

#    This file is part of the Minecraft Overviewer.
#
#    Minecraft Overviewer 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 3 of the License, or (at
#    your option) any later version.
#
#    Minecraft Overviewer 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 the Overviewer.  If not, see <http://www.gnu.org/licenses/>.

import time
import logging
import progressbar
import sys

class Observer(object):
    """Base class that defines the observer interface.
    """

    def __init__(self):
        self._current_value = None
        self._max_value = None
        self.start_time = None
        self.end_time = None

    def start(self, max_value):
        """Signals the start of whatever process. Must be called before update
        """
        self._set_max_value(max_value)
        self.start_time = time.time()
        self.update(0)
        return self

    def is_started(self):
        return self.start_time is not None

    def finish(self):
        """Signals the end of the processes, should be called after the
        process is done.
        """
        self.end_time = time.time()

    def is_finished(self):
        return self.end_time is not None

    def is_running(self):
        return self.is_started() and not self.is_finished()

    def add(self, amount):
        """Shortcut to update by increments instead of absolute values. Zero
        amounts are ignored.
        """
        if amount:
            self.update(self.get_current_value() + amount)

    def update(self, current_value):
        """Set the progress value. Should be between 0 and max_value. Returns
        whether this update is actually displayed.
        """
        self._current_value = current_value
        return False

    def get_percentage(self):
        """Get the current progress percentage. Assumes 100% if max_value is 0
        """
        if self.get_max_value() is 0:
            return 100.0
        else:
            return self.get_current_value() * 100.0 / self.get_max_value()

    def get_current_value(self):
        return self._current_value

    def get_max_value(self):
        return self._max_value

    def _set_max_value(self, max_value):
        self._max_value = max_value

class LoggingObserver(Observer):
    """Simple observer that just outputs status through logging.
    """
    def __init__(self):
        super(Observer, self).__init__()
        #this is an easy way to make the first update() call print a line
        self.last_update = -101

    def finish(self):
        logging.info("Rendered %d of %d.  %d%% complete", self.get_max_value(),
            self.get_max_value(), 100.0)
        super(LoggingObserver, self).finish()

    def update(self, current_value):
        super(LoggingObserver, self).update(current_value)
        if self._need_update():
            logging.info("Rendered %d of %d.  %d%% complete",
                self.get_current_value(), self.get_max_value(),
                self.get_percentage())
            self.last_update = current_value
            return True
        return False

    def _need_update(self):
        cur_val = self.get_current_value()
        if cur_val < 100:
            return cur_val - self.last_update > 10
        elif cur_val < 500:
            return cur_val - self.last_update > 50
        else:
            return cur_val - self.last_update > 100

default_widgets = ['Rendering: ', progressbar.FractionWidget(), ' (',
    progressbar.Percentage(), ') ', progressbar.Bar(left='[', right=']'),
    ' ', progressbar.ETA()]
class ProgressBarObserver(progressbar.ProgressBar, Observer):
    """Display progress through a progressbar.
    """

    #the progress bar is only updated in increments of this for performance
    UPDATE_INTERVAL = 25

    def __init__(self, widgets=default_widgets, term_width=None, fd=sys.stderr):
        super(ProgressBarObserver, self).__init__(widgets=widgets,
            term_width=term_width, fd=fd)
        self.last_update = 0 - (self.UPDATE_INTERVAL + 1)

    def start(self, max_value):
        self._set_max_value(max_value)
        super(ProgressBarObserver, self).start()

    def is_started(self):
        return self.start_time is not None

    def finish(self):
        self._end_time = time.time()
        super(ProgressBarObserver, self).finish()

    def update(self, current_value):
        if super(ProgressBarObserver, self).update(current_value):
            self.last_update = self.get_current_value()

    percentage = Observer.get_percentage

    def get_current_value(self):
        return self.currval

    def get_max_value(self):
        return self.maxval

    def _set_max_value(self, max_value):
        self.maxval = max_value

    def _need_update(self):
        return self.get_current_value() - self.last_update > self.UPDATE_INTERVAL