view mercurial/progress.py @ 30308:d500ddae7494

bdiff: don't check border condition in loop

`plast = a + len - 1`. So, this "for" loop iterates from "a" to "plast",
inclusive. So, `p == plast` can only be true on the final iteration
of the loop. So checking for it on every loop iteration is wasteful.

This patch simply decreases the upper bound of the loop by 1 and
adds an explicit check after iteration for the `p == plast` case.
We can't simply add 1 to the initial value for "i" because that
doesn't do the correct thing on empty input strings.

`perfbdiff -m 3041e4d59df2` on the Firefox repo becomes significantly
faster:

! wall 0.072763 comb 0.070000 user 0.070000 sys 0.000000 (best of 100)
! wall 0.053221 comb 0.060000 user 0.060000 sys 0.000000 (best of 100)

For the curious, this code has its origins in 8b067bde6679, which is
the changeset that introduced bdiff.c in 2005.

Also, GNU diffutils is able to perform a similar line-based diff in
under 20ms. So there's likely more perf wins to be found in this code.
One of them is the hashing algorithm. But it looks like mpm spent
some time testing hash collisions in d0c48891dd4a. I'd like to do the
same before switching away from lyhash, just to be on the safe side.

# progress.py progress bars related code
#
# Copyright (C) 2010 Augie Fackler <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import sys
import threading
import time

from .i18n import _
from . import encoding

def spacejoin(*args):
    return ' '.join(s for s in args if s)

def shouldprint(ui):
    return not (ui.quiet or ui.plain('progress')) and (
        ui._isatty(sys.stderr) or ui.configbool('progress', 'assume-tty'))

def fmtremaining(seconds):
    """format a number of remaining seconds in human readable way

    This will properly display seconds, minutes, hours, days if needed"""
    if seconds < 60:
        # i18n: format XX seconds as "XXs"
        return _("%02ds") % (seconds)
    minutes = seconds // 60
    if minutes < 60:
        seconds -= minutes * 60
        # i18n: format X minutes and YY seconds as "XmYYs"
        return _("%dm%02ds") % (minutes, seconds)
    # we're going to ignore seconds in this case
    minutes += 1
    hours = minutes // 60
    minutes -= hours * 60
    if hours < 30:
        # i18n: format X hours and YY minutes as "XhYYm"
        return _("%dh%02dm") % (hours, minutes)
    # we're going to ignore minutes in this case
    hours += 1
    days = hours // 24
    hours -= days * 24
    if days < 15:
        # i18n: format X days and YY hours as "XdYYh"
        return _("%dd%02dh") % (days, hours)
    # we're going to ignore hours in this case
    days += 1
    weeks = days // 7
    days -= weeks * 7
    if weeks < 55:
        # i18n: format X weeks and YY days as "XwYYd"
        return _("%dw%02dd") % (weeks, days)
    # we're going to ignore days and treat a year as 52 weeks
    weeks += 1
    years = weeks // 52
    weeks -= years * 52
    # i18n: format X years and YY weeks as "XyYYw"
    return _("%dy%02dw") % (years, weeks)

class progbar(object):
    def __init__(self, ui):
        self.ui = ui
        self._refreshlock = threading.Lock()
        self.resetstate()

    def resetstate(self):
        self.topics = []
        self.topicstates = {}
        self.starttimes = {}
        self.startvals = {}
        self.printed = False
        self.lastprint = time.time() + float(self.ui.config(
            'progress', 'delay', default=3))
        self.curtopic = None
        self.lasttopic = None
        self.indetcount = 0
        self.refresh = float(self.ui.config(
            'progress', 'refresh', default=0.1))
        self.changedelay = max(3 * self.refresh,
                               float(self.ui.config(
                                   'progress', 'changedelay', default=1)))
        self.order = self.ui.configlist(
            'progress', 'format',
            default=['topic', 'bar', 'number', 'estimate'])

    def show(self, now, topic, pos, item, unit, total):
        if not shouldprint(self.ui):
            return
        termwidth = self.width()
        self.printed = True
        head = ''
        needprogress = False
        tail = ''
        for indicator in self.order:
            add = ''
            if indicator == 'topic':
                add = topic
            elif indicator == 'number':
                if total:
                    add = ('% ' + str(len(str(total))) +
                           's/%s') % (pos, total)
                else:
                    add = str(pos)
            elif indicator.startswith('item') and item:
                slice = 'end'
                if '-' in indicator:
                    wid = int(indicator.split('-')[1])
                elif '+' in indicator:
                    slice = 'beginning'
                    wid = int(indicator.split('+')[1])
                else:
                    wid = 20
                if slice == 'end':
                    add = encoding.trim(item, wid, leftside=True)
                else:
                    add = encoding.trim(item, wid)
                add += (wid - encoding.colwidth(add)) * ' '
            elif indicator == 'bar':
                add = ''
                needprogress = True
            elif indicator == 'unit' and unit:
                add = unit
            elif indicator == 'estimate':
                add = self.estimate(topic, pos, total, now)
            elif indicator == 'speed':
                add = self.speed(topic, pos, unit, now)
            if not needprogress:
                head = spacejoin(head, add)
            else:
                tail = spacejoin(tail, add)
        if needprogress:
            used = 0
            if head:
                used += encoding.colwidth(head) + 1
            if tail:
                used += encoding.colwidth(tail) + 1
            progwidth = termwidth - used - 3
            if total and pos <= total:
                amt = pos * progwidth // total
                bar = '=' * (amt - 1)
                if amt > 0:
                    bar += '>'
                bar += ' ' * (progwidth - amt)
            else:
                progwidth -= 3
                self.indetcount += 1
                # mod the count by twice the width so we can make the
                # cursor bounce between the right and left sides
                amt = self.indetcount % (2 * progwidth)
                amt -= progwidth
                bar = (' ' * int(progwidth - abs(amt)) + '<=>' +
                       ' ' * int(abs(amt)))
            prog = ''.join(('[', bar , ']'))
            out = spacejoin(head, prog, tail)
        else:
            out = spacejoin(head, tail)
        sys.stderr.write('\r' + encoding.trim(out, termwidth))
        self.lasttopic = topic
        sys.stderr.flush()

    def clear(self):
        if not self.printed or not self.lastprint or not shouldprint(self.ui):
            return
        sys.stderr.write('\r%s\r' % (' ' * self.width()))
        if self.printed:
            # force immediate re-paint of progress bar
            self.lastprint = 0

    def complete(self):
        if not shouldprint(self.ui):
            return
        if self.ui.configbool('progress', 'clear-complete', default=True):
            self.clear()
        else:
            sys.stderr.write('\n')
        sys.stderr.flush()

    def width(self):
        tw = self.ui.termwidth()
        return min(int(self.ui.config('progress', 'width', default=tw)), tw)

    def estimate(self, topic, pos, total, now):
        if total is None:
            return ''
        initialpos = self.startvals[topic]
        target = total - initialpos
        delta = pos - initialpos
        if delta > 0:
            elapsed = now - self.starttimes[topic]
            # experimental config: progress.estimate
            if elapsed > float(
                self.ui.config('progress', 'estimate', default=2)):
                seconds = (elapsed * (target - delta)) // delta + 1
                return fmtremaining(seconds)
        return ''

    def speed(self, topic, pos, unit, now):
        initialpos = self.startvals[topic]
        delta = pos - initialpos
        elapsed = now - self.starttimes[topic]
        if elapsed > float(
            self.ui.config('progress', 'estimate', default=2)):
            return _('%d %s/sec') % (delta / elapsed, unit)
        return ''

    def _oktoprint(self, now):
        '''Check if conditions are met to print - e.g. changedelay elapsed'''
        if (self.lasttopic is None # first time we printed
            # not a topic change
            or self.curtopic == self.lasttopic
            # it's been long enough we should print anyway
            or now - self.lastprint >= self.changedelay):
            return True
        else:
            return False

    def progress(self, topic, pos, item='', unit='', total=None):
        now = time.time()
        self._refreshlock.acquire()
        try:
            if pos is None:
                self.starttimes.pop(topic, None)
                self.startvals.pop(topic, None)
                self.topicstates.pop(topic, None)
                # reset the progress bar if this is the outermost topic
                if self.topics and self.topics[0] == topic and self.printed:
                    self.complete()
                    self.resetstate()
                # truncate the list of topics assuming all topics within
                # this one are also closed
                if topic in self.topics:
                    self.topics = self.topics[:self.topics.index(topic)]
                    # reset the last topic to the one we just unwound to,
                    # so that higher-level topics will be stickier than
                    # lower-level topics
                    if self.topics:
                        self.lasttopic = self.topics[-1]
                    else:
                        self.lasttopic = None
            else:
                if topic not in self.topics:
                    self.starttimes[topic] = now
                    self.startvals[topic] = pos
                    self.topics.append(topic)
                self.topicstates[topic] = pos, item, unit, total
                self.curtopic = topic
                if now - self.lastprint >= self.refresh and self.topics:
                    if self._oktoprint(now):
                        self.lastprint = now
                        self.show(now, topic, *self.topicstates[topic])
        finally:
            self._refreshlock.release()