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# Copyright (C) 2010 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Record counting support for showing progress of revision fetch."""
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class RecordCounter(object):
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"""Container for maintains estimates of work requires for fetch.
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Instance of this class is used along with a progress bar to provide
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the user an estimate of the amount of work pending for a fetch (push,
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pull, branch, checkout) operation.
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self.initialized = False
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# Users of RecordCounter instance update progress bar every
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# _STEP_ records. We choose are reasonably high number to keep
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# display updates from being too frequent. This is an odd number
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# to ensure that the last digit of the records fetched in
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# fetches vs estimate ratio changes periodically.
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def is_initialized(self):
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return self.initialized
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def _estimate_max(self, key_count):
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"""Estimate the maximum amount of 'inserting stream' work.
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This is just an estimate.
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# Note: The magic number below is based of empirical data
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# based on 3 seperate projects. Estimatation can probably
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# be improved but this should work well for most cases.
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# The project used for the estimate (with approx. numbers) were:
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# lp:bzr with records_fetched = 7 * revs_required
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# lp:emacs with records_fetched = 8 * revs_required
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# bzr-svn checkout of lp:parrot = 10.63 * revs_required
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# Hence, 10.3 was chosen as for a realistic progress bar as:
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# 1. If records fetched is is lower than 10.3x then we simply complete
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# with 10.3x. Under promise, over deliver.
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# 2. In case of remote fetch, when we start the count fetch vs estimate
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# display with revs_required/estimate, having a multiplier with a
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# decimal point produces a realistic looking _estimate_ number rather
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# than using something like 3125/31250 (for 10x)
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# 3. Based on the above data, the possibility of overshooting this
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# factor is minimal, and in case of an overshoot the estimate value
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# should not need to be corrected too many times.
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return int(key_count * 10.3)
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def setup(self, key_count, current=0):
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"""Setup RecordCounter with basic estimate of work pending.
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Setup self.max and self.current to reflect the amount of work
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self.current = current
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self.key_count = key_count
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self.max = self._estimate_max(key_count)
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self.initialized = True
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def increment(self, count):
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"""Increment self.current by count.
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Apart from incrementing self.current by count, also ensure
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that self.max > self.current.
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if self.current > self.max:
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self.max += self.key_count
added
removed
bzrlib/recordcounter.py
