progress: force a repaint of a printed progress bar after a clear()

This avoids some visual flickering of the progress bar in convert and
probably some other operations. Previously, a line of output would
erase the progress bar, and then it would wait `progress.refresh`
seconds (default of 0.1) before redrawing the progress bar. Now if
we've ever painted a progress bar, we schedule the progress bar for
immediate repainting on the next progress call, which helps lend the
illusion that the progress bar is "always" there. In practice, it's
merely there more of the time, but it ends up being a lot easier to
read during convert.

mercurial/progress.py

@@ -1,253 +1,256
 # 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()) and (
         ui._isatty(sys.stderr) or ui.configbool('progress', 'assume-tty'))
 
 def fmtremaining(seconds):
     """format a number of remaining seconds in humain 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 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()