view hgext/convert/gnuarch.py @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

# gnuarch.py - GNU Arch support for the convert extension
#
#  Copyright 2008, 2009 Aleix Conchillo Flaque <[e-mail]>
#  and others
#
# 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 email.parser as emailparser
import os
import shutil
import stat
import tempfile

from mercurial.i18n import _
from mercurial import (
    encoding,
    error,
    pycompat,
    util,
)
from mercurial.utils import (
    dateutil,
    procutil,
)
from . import common

class gnuarch_source(common.converter_source, common.commandline):

    class gnuarch_rev(object):
        def __init__(self, rev):
            self.rev = rev
            self.summary = ''
            self.date = None
            self.author = ''
            self.continuationof = None
            self.add_files = []
            self.mod_files = []
            self.del_files = []
            self.ren_files = {}
            self.ren_dirs = {}

    def __init__(self, ui, repotype, path, revs=None):
        super(gnuarch_source, self).__init__(ui, repotype, path, revs=revs)

        if not os.path.exists(os.path.join(path, '{arch}')):
            raise common.NoRepo(_("%s does not look like a GNU Arch repository")
                         % path)

        # Could use checktool, but we want to check for baz or tla.
        self.execmd = None
        if procutil.findexe('baz'):
            self.execmd = 'baz'
        else:
            if procutil.findexe('tla'):
                self.execmd = 'tla'
            else:
                raise error.Abort(_('cannot find a GNU Arch tool'))

        common.commandline.__init__(self, ui, self.execmd)

        self.path = os.path.realpath(path)
        self.tmppath = None

        self.treeversion = None
        self.lastrev = None
        self.changes = {}
        self.parents = {}
        self.tags = {}
        self.catlogparser = emailparser.Parser()
        self.encoding = encoding.encoding
        self.archives = []

    def before(self):
        # Get registered archives
        self.archives = [i.rstrip('\n')
                         for i in self.runlines0('archives', '-n')]

        if self.execmd == 'tla':
            output = self.run0('tree-version', self.path)
        else:
            output = self.run0('tree-version', '-d', self.path)
        self.treeversion = output.strip()

        # Get name of temporary directory
        version = self.treeversion.split('/')
        self.tmppath = os.path.join(tempfile.gettempdir(),
                                    'hg-%s' % version[1])

        # Generate parents dictionary
        self.parents[None] = []
        treeversion = self.treeversion
        child = None
        while treeversion:
            self.ui.status(_('analyzing tree version %s...\n') % treeversion)

            archive = treeversion.split('/')[0]
            if archive not in self.archives:
                self.ui.status(_('tree analysis stopped because it points to '
                                 'an unregistered archive %s...\n') % archive)
                break

            # Get the complete list of revisions for that tree version
            output, status = self.runlines('revisions', '-r', '-f', treeversion)
            self.checkexit(status, 'failed retrieving revisions for %s'
                           % treeversion)

            # No new iteration unless a revision has a continuation-of header
            treeversion = None

            for l in output:
                rev = l.strip()
                self.changes[rev] = self.gnuarch_rev(rev)
                self.parents[rev] = []

                # Read author, date and summary
                catlog, status = self.run('cat-log', '-d', self.path, rev)
                if status:
                    catlog  = self.run0('cat-archive-log', rev)
                self._parsecatlog(catlog, rev)

                # Populate the parents map
                self.parents[child].append(rev)

                # Keep track of the current revision as the child of the next
                # revision scanned
                child = rev

                # Check if we have to follow the usual incremental history
                # or if we have to 'jump' to a different treeversion given
                # by the continuation-of header.
                if self.changes[rev].continuationof:
                    treeversion = '--'.join(
                        self.changes[rev].continuationof.split('--')[:-1])
                    break

                # If we reached a base-0 revision w/o any continuation-of
                # header, it means the tree history ends here.
                if rev[-6:] == 'base-0':
                    break

    def after(self):
        self.ui.debug('cleaning up %s\n' % self.tmppath)
        shutil.rmtree(self.tmppath, ignore_errors=True)

    def getheads(self):
        return self.parents[None]

    def getfile(self, name, rev):
        if rev != self.lastrev:
            raise error.Abort(_('internal calling inconsistency'))

        if not os.path.lexists(os.path.join(self.tmppath, name)):
            return None, None

        return self._getfile(name, rev)

    def getchanges(self, rev, full):
        if full:
            raise error.Abort(_("convert from arch does not support --full"))
        self._update(rev)
        changes = []
        copies = {}

        for f in self.changes[rev].add_files:
            changes.append((f, rev))

        for f in self.changes[rev].mod_files:
            changes.append((f, rev))

        for f in self.changes[rev].del_files:
            changes.append((f, rev))

        for src in self.changes[rev].ren_files:
            to = self.changes[rev].ren_files[src]
            changes.append((src, rev))
            changes.append((to, rev))
            copies[to] = src

        for src in self.changes[rev].ren_dirs:
            to = self.changes[rev].ren_dirs[src]
            chgs, cps = self._rendirchanges(src, to)
            changes += [(f, rev) for f in chgs]
            copies.update(cps)

        self.lastrev = rev
        return sorted(set(changes)), copies, set()

    def getcommit(self, rev):
        changes = self.changes[rev]
        return common.commit(author=changes.author, date=changes.date,
                             desc=changes.summary, parents=self.parents[rev],
                             rev=rev)

    def gettags(self):
        return self.tags

    def _execute(self, cmd, *args, **kwargs):
        cmdline = [self.execmd, cmd]
        cmdline += args
        cmdline = [procutil.shellquote(arg) for arg in cmdline]
        cmdline += ['>', os.devnull, '2>', os.devnull]
        cmdline = procutil.quotecommand(' '.join(cmdline))
        self.ui.debug(cmdline, '\n')
        return os.system(pycompat.rapply(procutil.tonativestr, cmdline))

    def _update(self, rev):
        self.ui.debug('applying revision %s...\n' % rev)
        changeset, status = self.runlines('replay', '-d', self.tmppath,
                                              rev)
        if status:
            # Something went wrong while merging (baz or tla
            # issue?), get latest revision and try from there
            shutil.rmtree(self.tmppath, ignore_errors=True)
            self._obtainrevision(rev)
        else:
            old_rev = self.parents[rev][0]
            self.ui.debug('computing changeset between %s and %s...\n'
                          % (old_rev, rev))
            self._parsechangeset(changeset, rev)

    def _getfile(self, name, rev):
        mode = os.lstat(os.path.join(self.tmppath, name)).st_mode
        if stat.S_ISLNK(mode):
            data = util.readlink(os.path.join(self.tmppath, name))
            if mode:
                mode = 'l'
            else:
                mode = ''
        else:
            data = util.readfile(os.path.join(self.tmppath, name))
            mode = (mode & 0o111) and 'x' or ''
        return data, mode

    def _exclude(self, name):
        exclude = ['{arch}', '.arch-ids', '.arch-inventory']
        for exc in exclude:
            if name.find(exc) != -1:
                return True
        return False

    def _readcontents(self, path):
        files = []
        contents = os.listdir(path)
        while len(contents) > 0:
            c = contents.pop()
            p = os.path.join(path, c)
            # os.walk could be used, but here we avoid internal GNU
            # Arch files and directories, thus saving a lot time.
            if not self._exclude(p):
                if os.path.isdir(p):
                    contents += [os.path.join(c, f) for f in os.listdir(p)]
                else:
                    files.append(c)
        return files

    def _rendirchanges(self, src, dest):
        changes = []
        copies = {}
        files = self._readcontents(os.path.join(self.tmppath, dest))
        for f in files:
            s = os.path.join(src, f)
            d = os.path.join(dest, f)
            changes.append(s)
            changes.append(d)
            copies[d] = s
        return changes, copies

    def _obtainrevision(self, rev):
        self.ui.debug('obtaining revision %s...\n' % rev)
        output = self._execute('get', rev, self.tmppath)
        self.checkexit(output)
        self.ui.debug('analyzing revision %s...\n' % rev)
        files = self._readcontents(self.tmppath)
        self.changes[rev].add_files += files

    def _stripbasepath(self, path):
        if path.startswith('./'):
            return path[2:]
        return path

    def _parsecatlog(self, data, rev):
        try:
            catlog = self.catlogparser.parsestr(data)

            # Commit date
            self.changes[rev].date = dateutil.datestr(
                dateutil.strdate(catlog['Standard-date'],
                             '%Y-%m-%d %H:%M:%S'))

            # Commit author
            self.changes[rev].author = self.recode(catlog['Creator'])

            # Commit description
            self.changes[rev].summary = '\n\n'.join((catlog['Summary'],
                                                    catlog.get_payload()))
            self.changes[rev].summary = self.recode(self.changes[rev].summary)

            # Commit revision origin when dealing with a branch or tag
            if 'Continuation-of' in catlog:
                self.changes[rev].continuationof = self.recode(
                    catlog['Continuation-of'])
        except Exception:
            raise error.Abort(_('could not parse cat-log of %s') % rev)

    def _parsechangeset(self, data, rev):
        for l in data:
            l = l.strip()
            # Added file (ignore added directory)
            if l.startswith('A') and not l.startswith('A/'):
                file = self._stripbasepath(l[1:].strip())
                if not self._exclude(file):
                    self.changes[rev].add_files.append(file)
            # Deleted file (ignore deleted directory)
            elif l.startswith('D') and not l.startswith('D/'):
                file = self._stripbasepath(l[1:].strip())
                if not self._exclude(file):
                    self.changes[rev].del_files.append(file)
            # Modified binary file
            elif l.startswith('Mb'):
                file = self._stripbasepath(l[2:].strip())
                if not self._exclude(file):
                    self.changes[rev].mod_files.append(file)
            # Modified link
            elif l.startswith('M->'):
                file = self._stripbasepath(l[3:].strip())
                if not self._exclude(file):
                    self.changes[rev].mod_files.append(file)
            # Modified file
            elif l.startswith('M'):
                file = self._stripbasepath(l[1:].strip())
                if not self._exclude(file):
                    self.changes[rev].mod_files.append(file)
            # Renamed file (or link)
            elif l.startswith('=>'):
                files = l[2:].strip().split(' ')
                if len(files) == 1:
                    files = l[2:].strip().split('\t')
                src = self._stripbasepath(files[0])
                dst = self._stripbasepath(files[1])
                if not self._exclude(src) and not self._exclude(dst):
                    self.changes[rev].ren_files[src] = dst
            # Conversion from file to link or from link to file (modified)
            elif l.startswith('ch'):
                file = self._stripbasepath(l[2:].strip())
                if not self._exclude(file):
                    self.changes[rev].mod_files.append(file)
            # Renamed directory
            elif l.startswith('/>'):
                dirs = l[2:].strip().split(' ')
                if len(dirs) == 1:
                    dirs = l[2:].strip().split('\t')
                src = self._stripbasepath(dirs[0])
                dst = self._stripbasepath(dirs[1])
                if not self._exclude(src) and not self._exclude(dst):
                    self.changes[rev].ren_dirs[src] = dst