view mercurial/progress.py @ 45390:7d24201b6447

worker: don't expose readinto() on _blockingreader since pickle is picky

The `pickle` module expects the input to be buffered and a whole
object to be available when `pickle.load()` is called, which is not
necessarily true when we send data from workers back to the parent
process (i.e., it seems like a bad assumption for the `pickle` module
to make). We added a workaround for that in
https://phab.mercurial-scm.org/D8076, which made `read()` continue
until all the requested bytes have been read.

As we found out at work after a lot of investigation (I've spent the
last two days on this), the native version of `pickle.load()` has
started calling `readinto()` on the input since Python 3.8. That
started being called in
https://github.com/python/cpython/commit/91f4380cedbae32b49adbea2518014a5624c6523
(and only by the C version of `pickle.load()`)). Before that, it was
only `read()` and `readline()` that were called. The problem with that
was that `readinto()` on our `_blockingreader` was simply delegating
to the underlying, *unbuffered* object. The symptom we saw was that
`hg fix` started failing sometimes on Python 3.8 on Mac. It failed
very relyable in some cases. I still haven't figured out under what
circumstances it fails and I've been unable to reproduce it in test
cases (I've tried writing larger amounts of data, using different
numbers of workers, and making the formatters sleep). I have, however,
been able to reproduce it 3-4 times on Linux, but then it stopped
reproducing on the following few hundred attempts.

To fix the problem, we can simply remove the implementation of
`readinto()`, since the unpickler will then fall back to calling
`read()`. The fallback was added a bit later, in
https://github.com/python/cpython/commit/b19f7ecfa3adc6ba1544225317b9473649815b38. However,
that commit also added checking that what `read()` returns is a
`bytes`, so we also need to convert the `bytearray` we use into
that. I was able to add a test for that failure at least.

Differential Revision: https://phab.mercurial-scm.org/D8928

# 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 errno
import threading
import time

from .i18n import _
from . import encoding


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


def shouldprint(ui):
    return not (ui.quiet or ui.plain(b'progress')) and (
        ui._isatty(ui.ferr) or ui.configbool(b'progress', b'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 _(b"%02ds") % seconds
    minutes = seconds // 60
    if minutes < 60:
        seconds -= minutes * 60
        # i18n: format X minutes and YY seconds as "XmYYs"
        return _(b"%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 _(b"%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 _(b"%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 _(b"%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 _(b"%dy%02dw") % (years, weeks)


# file_write() and file_flush() of Python 2 do not restart on EINTR if
# the file is attached to a "slow" device (e.g. a terminal) and raise
# IOError. We cannot know how many bytes would be written by file_write(),
# but a progress text is known to be short enough to be written by a
# single write() syscall, so we can just retry file_write() with the whole
# text. (issue5532)
#
# This should be a short-term workaround. We'll need to fix every occurrence
# of write() to a terminal or pipe.
def _eintrretry(func, *args):
    while True:
        try:
            return func(*args)
        except IOError as err:
            if err.errno == errno.EINTR:
                continue
            raise


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(b'progress', b'delay')
        )
        self.curtopic = None
        self.lasttopic = None
        self.indetcount = 0
        self.refresh = float(self.ui.config(b'progress', b'refresh'))
        self.changedelay = max(
            3 * self.refresh, float(self.ui.config(b'progress', b'changedelay'))
        )
        self.order = self.ui.configlist(b'progress', b'format')
        self.estimateinterval = self.ui.configwith(
            float, b'progress', b'estimateinterval'
        )

    def show(self, now, topic, pos, item, unit, total):
        if not shouldprint(self.ui):
            return
        termwidth = self.width()
        self.printed = True
        head = b''
        needprogress = False
        tail = b''
        for indicator in self.order:
            add = b''
            if indicator == b'topic':
                add = topic
            elif indicator == b'number':
                if total:
                    add = b'%*d/%d' % (len(str(total)), pos, total)
                else:
                    add = b'%d' % pos
            elif indicator.startswith(b'item') and item:
                slice = b'end'
                if b'-' in indicator:
                    wid = int(indicator.split(b'-')[1])
                elif b'+' in indicator:
                    slice = b'beginning'
                    wid = int(indicator.split(b'+')[1])
                else:
                    wid = 20
                if slice == b'end':
                    add = encoding.trim(item, wid, leftside=True)
                else:
                    add = encoding.trim(item, wid)
                add += (wid - encoding.colwidth(add)) * b' '
            elif indicator == b'bar':
                add = b''
                needprogress = True
            elif indicator == b'unit' and unit:
                add = unit
            elif indicator == b'estimate':
                add = self.estimate(topic, pos, total, now)
            elif indicator == b'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 = b'=' * (amt - 1)
                if amt > 0:
                    bar += b'>'
                bar += b' ' * (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 = (
                    b' ' * int(progwidth - abs(amt))
                    + b'<=>'
                    + b' ' * int(abs(amt))
                )
            prog = b''.join((b'[', bar, b']'))
            out = spacejoin(head, prog, tail)
        else:
            out = spacejoin(head, tail)
        self._writeerr(b'\r' + encoding.trim(out, termwidth))
        self.lasttopic = topic
        self._flusherr()

    def clear(self):
        if not self.printed or not self.lastprint or not shouldprint(self.ui):
            return
        self._writeerr(b'\r%s\r' % (b' ' * self.width()))
        self._flusherr()
        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(b'progress', b'clear-complete'):
            self.clear()
        else:
            self._writeerr(b'\n')
        self._flusherr()

    def _flusherr(self):
        _eintrretry(self.ui.ferr.flush)

    def _writeerr(self, msg):
        _eintrretry(self.ui.ferr.write, msg)

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

    def estimate(self, topic, pos, total, now):
        if total is None:
            return b''
        initialpos = self.startvals[topic]
        target = total - initialpos
        delta = pos - initialpos
        if delta > 0:
            elapsed = now - self.starttimes[topic]
            seconds = (elapsed * (target - delta)) // delta + 1
            return fmtremaining(seconds)
        return b''

    def speed(self, topic, pos, unit, now):
        initialpos = self.startvals[topic]
        delta = pos - initialpos
        elapsed = now - self.starttimes[topic]
        if elapsed > 0:
            return _(b'%d %s/sec') % (delta / elapsed, unit)
        return b''

    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 _calibrateestimate(self, topic, now, pos):
        '''Adjust starttimes and startvals for topic so ETA works better

        If progress is non-linear (ex. get much slower in the last minute),
        it's more friendly to only use a recent time span for ETA and speed
        calculation.

            [======================================>       ]
                                             ^^^^^^^
                           estimateinterval, only use this for estimation
        '''
        interval = self.estimateinterval
        if interval <= 0:
            return
        elapsed = now - self.starttimes[topic]
        if elapsed > interval:
            delta = pos - self.startvals[topic]
            newdelta = delta * interval / elapsed
            # If a stall happens temporarily, ETA could change dramatically
            # frequently. This is to avoid such dramatical change and make ETA
            # smoother.
            if newdelta < 0.1:
                return
            self.startvals[topic] = pos - newdelta
            self.starttimes[topic] = now - interval

    def progress(self, topic, pos, item=b'', unit=b'', total=None):
        if pos is None:
            self.closetopic(topic)
            return
        now = time.time()
        with self._refreshlock:
            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
            self._calibrateestimate(topic, now, pos)
            if now - self.lastprint >= self.refresh and self.topics:
                if self._oktoprint(now):
                    self.lastprint = now
                    self.show(now, topic, *self.topicstates[topic])

    def closetopic(self, topic):
        with self._refreshlock:
            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