clean up observer code

overviewer_core/observer.py

@@ -0,0 +1,147 @@
+#    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):
+        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):
+        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):
+        if amount:
+            self.update(self.get_current_value() + amount)
+
+    def update(self, current_value):
+        """
+        """
+        self._current_value = current_value
+        return False
+
+    def get_percentage(self):
+        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.
+    """
+
+    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 = -101
+
+    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