view contrib/synthrepo.py @ 43271:99394e6c5d12

rust-dirstate-status: add first Rust implementation of `dirstate.status`

Note: This patch also added the rayon crate as a Cargo dependency. It will
help us immensely in making Rust code parallel and easy to maintain. It is
a stable, well-known, and supported crate maintained by people on the Rust
team.

The current `dirstate.status` method has grown over the years through bug
reports and new features to the point where it got too big and too complex.

This series does not yet improve the logic, but adds a Rust fast-path to speed
up certain cases.

Tested on mozilla-try-2019-02-18 with zstd compression:
    - `hg diff` on an empty working copy:
        - c: 1.64(+-)0.04s
        - rust+c before this change: 2.84(+-)0.1s
        - rust+c: 849(+-)40ms
    - `hg commit` when creating a file:
        - c: 5.960s
        - rust+c before this change: 5.828s
        - rust+c: 4.668s
    - `hg commit` when updating a file:
        - c: 4.866s
        - rust+c before this change: 4.371s
        - rust+c: 3.855s
    - `hg status -mard`
        - c: 1.82(+-)0.04s
        - rust+c before this change: 2.64(+-)0.1s
        - rust+c: 896(+-)30ms

The numbers are clear: the current Rust `dirstatemap` implementation is super
slow, its performance needs to be addressed.
This will be done in a future series, immediately after this one, with the goal
of getting Rust to be at least to the speed of the Python + C implementation
in all cases before the 5.2 freeze. At worse, we gate dirstatemap to only be used
in those cases.

Cases where the fast-path is not executed:
    - for commands that need ignore support (`status`, for example)
    - if subrepos are found (should not be hard to add, but winter is coming)
    - any other matcher than an `alwaysmatcher`, like patterns, etc.
    - with extensions like `sparse` and `fsmonitor`

The next step after this is to rethink the logic to be closer to
Jane Street's Valentin Gatien-Baron's Rust fast-path which does a lot less
work when possible.

Differential Revision: https://phab.mercurial-scm.org/D7058

# synthrepo.py - repo synthesis
#
# Copyright 2012 Facebook
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''synthesize structurally interesting change history

This extension is useful for creating a repository with properties
that are statistically similar to an existing repository. During
analysis, a simple probability table is constructed from the history
of an existing repository.  During synthesis, these properties are
reconstructed.

Properties that are analyzed and synthesized include the following:

- Lines added or removed when an existing file is modified
- Number and sizes of files added
- Number of files removed
- Line lengths
- Topological distance to parent changeset(s)
- Probability of a commit being a merge
- Probability of a newly added file being added to a new directory
- Interarrival time, and time zone, of commits
- Number of files in each directory

A few obvious properties that are not currently handled realistically:

- Merges are treated as regular commits with two parents, which is not
  realistic
- Modifications are not treated as operations on hunks of lines, but
  as insertions and deletions of randomly chosen single lines
- Committer ID (always random)
- Executability of files
- Symlinks and binary files are ignored
'''

from __future__ import absolute_import
import bisect
import collections
import itertools
import json
import os
import random
import sys
import time

from mercurial.i18n import _
from mercurial.node import (
    nullid,
    nullrev,
    short,
)
from mercurial import (
    context,
    diffutil,
    error,
    hg,
    patch,
    pycompat,
    registrar,
    scmutil,
)
from mercurial.utils import dateutil

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

cmdtable = {}
command = registrar.command(cmdtable)

newfile = {'new fi', 'rename', 'copy f', 'copy t'}


def zerodict():
    return collections.defaultdict(lambda: 0)


def roundto(x, k):
    if x > k * 2:
        return int(round(x / float(k)) * k)
    return int(round(x))


def parsegitdiff(lines):
    filename, mar, lineadd, lineremove = None, None, zerodict(), 0
    binary = False
    for line in lines:
        start = line[:6]
        if start == 'diff -':
            if filename:
                yield filename, mar, lineadd, lineremove, binary
            mar, lineadd, lineremove, binary = 'm', zerodict(), 0, False
            filename = patch.gitre.match(line).group(1)
        elif start in newfile:
            mar = 'a'
        elif start == 'GIT bi':
            binary = True
        elif start == 'delete':
            mar = 'r'
        elif start:
            s = start[0]
            if s == '-' and not line.startswith('--- '):
                lineremove += 1
            elif s == '+' and not line.startswith('+++ '):
                lineadd[roundto(len(line) - 1, 5)] += 1
    if filename:
        yield filename, mar, lineadd, lineremove, binary


@command(
    'analyze',
    [
        ('o', 'output', '', _('write output to given file'), _('FILE')),
        ('r', 'rev', [], _('analyze specified revisions'), _('REV')),
    ],
    _('hg analyze'),
    optionalrepo=True,
)
def analyze(ui, repo, *revs, **opts):
    '''create a simple model of a repository to use for later synthesis

    This command examines every changeset in the given range (or all
    of history if none are specified) and creates a simple statistical
    model of the history of the repository. It also measures the directory
    structure of the repository as checked out.

    The model is written out to a JSON file, and can be used by
    :hg:`synthesize` to create or augment a repository with synthetic
    commits that have a structure that is statistically similar to the
    analyzed repository.
    '''
    root = repo.root
    if not root.endswith(os.path.sep):
        root += os.path.sep

    revs = list(revs)
    revs.extend(opts['rev'])
    if not revs:
        revs = [':']

    output = opts['output']
    if not output:
        output = os.path.basename(root) + '.json'

    if output == '-':
        fp = sys.stdout
    else:
        fp = open(output, 'w')

    # Always obtain file counts of each directory in the given root directory.
    def onerror(e):
        ui.warn(_('error walking directory structure: %s\n') % e)

    dirs = {}
    rootprefixlen = len(root)
    for dirpath, dirnames, filenames in os.walk(root, onerror=onerror):
        dirpathfromroot = dirpath[rootprefixlen:]
        dirs[dirpathfromroot] = len(filenames)
        if '.hg' in dirnames:
            dirnames.remove('.hg')

    lineschanged = zerodict()
    children = zerodict()
    p1distance = zerodict()
    p2distance = zerodict()
    linesinfilesadded = zerodict()
    fileschanged = zerodict()
    filesadded = zerodict()
    filesremoved = zerodict()
    linelengths = zerodict()
    interarrival = zerodict()
    parents = zerodict()
    dirsadded = zerodict()
    tzoffset = zerodict()

    # If a mercurial repo is available, also model the commit history.
    if repo:
        revs = scmutil.revrange(repo, revs)
        revs.sort()

        progress = ui.makeprogress(
            _('analyzing'), unit=_('changesets'), total=len(revs)
        )
        for i, rev in enumerate(revs):
            progress.update(i)
            ctx = repo[rev]
            pl = ctx.parents()
            pctx = pl[0]
            prev = pctx.rev()
            children[prev] += 1
            p1distance[rev - prev] += 1
            parents[len(pl)] += 1
            tzoffset[ctx.date()[1]] += 1
            if len(pl) > 1:
                p2distance[rev - pl[1].rev()] += 1
            if prev == rev - 1:
                lastctx = pctx
            else:
                lastctx = repo[rev - 1]
            if lastctx.rev() != nullrev:
                timedelta = ctx.date()[0] - lastctx.date()[0]
                interarrival[roundto(timedelta, 300)] += 1
            diffopts = diffutil.diffallopts(ui, {'git': True})
            diff = sum(
                (d.splitlines() for d in ctx.diff(pctx, opts=diffopts)), []
            )
            fileadds, diradds, fileremoves, filechanges = 0, 0, 0, 0
            for filename, mar, lineadd, lineremove, isbin in parsegitdiff(diff):
                if isbin:
                    continue
                added = sum(pycompat.itervalues(lineadd), 0)
                if mar == 'm':
                    if added and lineremove:
                        lineschanged[
                            roundto(added, 5), roundto(lineremove, 5)
                        ] += 1
                        filechanges += 1
                elif mar == 'a':
                    fileadds += 1
                    if '/' in filename:
                        filedir = filename.rsplit('/', 1)[0]
                        if filedir not in pctx.dirs():
                            diradds += 1
                    linesinfilesadded[roundto(added, 5)] += 1
                elif mar == 'r':
                    fileremoves += 1
                for length, count in lineadd.iteritems():
                    linelengths[length] += count
            fileschanged[filechanges] += 1
            filesadded[fileadds] += 1
            dirsadded[diradds] += 1
            filesremoved[fileremoves] += 1
        progress.complete()

    invchildren = zerodict()

    for rev, count in children.iteritems():
        invchildren[count] += 1

    if output != '-':
        ui.status(_('writing output to %s\n') % output)

    def pronk(d):
        return sorted(d.iteritems(), key=lambda x: x[1], reverse=True)

    json.dump(
        {
            'revs': len(revs),
            'initdirs': pronk(dirs),
            'lineschanged': pronk(lineschanged),
            'children': pronk(invchildren),
            'fileschanged': pronk(fileschanged),
            'filesadded': pronk(filesadded),
            'linesinfilesadded': pronk(linesinfilesadded),
            'dirsadded': pronk(dirsadded),
            'filesremoved': pronk(filesremoved),
            'linelengths': pronk(linelengths),
            'parents': pronk(parents),
            'p1distance': pronk(p1distance),
            'p2distance': pronk(p2distance),
            'interarrival': pronk(interarrival),
            'tzoffset': pronk(tzoffset),
        },
        fp,
    )
    fp.close()


@command(
    'synthesize',
    [
        ('c', 'count', 0, _('create given number of commits'), _('COUNT')),
        ('', 'dict', '', _('path to a dictionary of words'), _('FILE')),
        ('', 'initfiles', 0, _('initial file count to create'), _('COUNT')),
    ],
    _('hg synthesize [OPTION].. DESCFILE'),
)
def synthesize(ui, repo, descpath, **opts):
    '''synthesize commits based on a model of an existing repository

    The model must have been generated by :hg:`analyze`. Commits will
    be generated randomly according to the probabilities described in
    the model. If --initfiles is set, the repository will be seeded with
    the given number files following the modeled repository's directory
    structure.

    When synthesizing new content, commit descriptions, and user
    names, words will be chosen randomly from a dictionary that is
    presumed to contain one word per line. Use --dict to specify the
    path to an alternate dictionary to use.
    '''
    try:
        fp = hg.openpath(ui, descpath)
    except Exception as err:
        raise error.Abort('%s: %s' % (descpath, err[0].strerror))
    desc = json.load(fp)
    fp.close()

    def cdf(l):
        if not l:
            return [], []
        vals, probs = zip(*sorted(l, key=lambda x: x[1], reverse=True))
        t = float(sum(probs, 0))
        s, cdfs = 0, []
        for v in probs:
            s += v
            cdfs.append(s / t)
        return vals, cdfs

    lineschanged = cdf(desc['lineschanged'])
    fileschanged = cdf(desc['fileschanged'])
    filesadded = cdf(desc['filesadded'])
    dirsadded = cdf(desc['dirsadded'])
    filesremoved = cdf(desc['filesremoved'])
    linelengths = cdf(desc['linelengths'])
    parents = cdf(desc['parents'])
    p1distance = cdf(desc['p1distance'])
    p2distance = cdf(desc['p2distance'])
    interarrival = cdf(desc['interarrival'])
    linesinfilesadded = cdf(desc['linesinfilesadded'])
    tzoffset = cdf(desc['tzoffset'])

    dictfile = opts.get('dict') or '/usr/share/dict/words'
    try:
        fp = open(dictfile, 'rU')
    except IOError as err:
        raise error.Abort('%s: %s' % (dictfile, err.strerror))
    words = fp.read().splitlines()
    fp.close()

    initdirs = {}
    if desc['initdirs']:
        for k, v in desc['initdirs']:
            initdirs[k.encode('utf-8').replace('.hg', '_hg')] = v
        initdirs = renamedirs(initdirs, words)
    initdirscdf = cdf(initdirs)

    def pick(cdf):
        return cdf[0][bisect.bisect_left(cdf[1], random.random())]

    def pickpath():
        return os.path.join(pick(initdirscdf), random.choice(words))

    def makeline(minimum=0):
        total = max(minimum, pick(linelengths))
        c, l = 0, []
        while c < total:
            w = random.choice(words)
            c += len(w) + 1
            l.append(w)
        return ' '.join(l)

    wlock = repo.wlock()
    lock = repo.lock()

    nevertouch = {'.hgsub', '.hgignore', '.hgtags'}

    _synthesizing = _('synthesizing')
    _files = _('initial files')
    _changesets = _('changesets')

    # Synthesize a single initial revision adding files to the repo according
    # to the modeled directory structure.
    initcount = int(opts['initfiles'])
    if initcount and initdirs:
        pctx = repo['.']
        dirs = set(pctx.dirs())
        files = {}

        def validpath(path):
            # Don't pick filenames which are already directory names.
            if path in dirs:
                return False
            # Don't pick directories which were used as file names.
            while path:
                if path in files:
                    return False
                path = os.path.dirname(path)
            return True

        progress = ui.makeprogress(_synthesizing, unit=_files, total=initcount)
        for i in pycompat.xrange(0, initcount):
            progress.update(i)

            path = pickpath()
            while not validpath(path):
                path = pickpath()
            data = '%s contents\n' % path
            files[path] = data
            dir = os.path.dirname(path)
            while dir and dir not in dirs:
                dirs.add(dir)
                dir = os.path.dirname(dir)

        def filectxfn(repo, memctx, path):
            return context.memfilectx(repo, memctx, path, files[path])

        progress.complete()
        message = 'synthesized wide repo with %d files' % (len(files),)
        mc = context.memctx(
            repo,
            [pctx.node(), nullid],
            message,
            files,
            filectxfn,
            ui.username(),
            '%d %d' % dateutil.makedate(),
        )
        initnode = mc.commit()
        if ui.debugflag:
            hexfn = hex
        else:
            hexfn = short
        ui.status(
            _('added commit %s with %d files\n') % (hexfn(initnode), len(files))
        )

    # Synthesize incremental revisions to the repository, adding repo depth.
    count = int(opts['count'])
    heads = set(map(repo.changelog.rev, repo.heads()))
    progress = ui.makeprogress(_synthesizing, unit=_changesets, total=count)
    for i in pycompat.xrange(count):
        progress.update(i)

        node = repo.changelog.node
        revs = len(repo)

        def pickhead(heads, distance):
            if heads:
                lheads = sorted(heads)
                rev = revs - min(pick(distance), revs)
                if rev < lheads[-1]:
                    rev = lheads[bisect.bisect_left(lheads, rev)]
                else:
                    rev = lheads[-1]
                return rev, node(rev)
            return nullrev, nullid

        r1 = revs - min(pick(p1distance), revs)
        p1 = node(r1)

        # the number of heads will grow without bound if we use a pure
        # model, so artificially constrain their proliferation
        toomanyheads = len(heads) > random.randint(1, 20)
        if p2distance[0] and (pick(parents) == 2 or toomanyheads):
            r2, p2 = pickhead(heads.difference([r1]), p2distance)
        else:
            r2, p2 = nullrev, nullid

        pl = [p1, p2]
        pctx = repo[r1]
        mf = pctx.manifest()
        mfk = mf.keys()
        changes = {}
        if mfk:
            for __ in pycompat.xrange(pick(fileschanged)):
                for __ in pycompat.xrange(10):
                    fctx = pctx.filectx(random.choice(mfk))
                    path = fctx.path()
                    if not (
                        path in nevertouch
                        or fctx.isbinary()
                        or 'l' in fctx.flags()
                    ):
                        break
                lines = fctx.data().splitlines()
                add, remove = pick(lineschanged)
                for __ in pycompat.xrange(remove):
                    if not lines:
                        break
                    del lines[random.randrange(0, len(lines))]
                for __ in pycompat.xrange(add):
                    lines.insert(random.randint(0, len(lines)), makeline())
                path = fctx.path()
                changes[path] = '\n'.join(lines) + '\n'
            for __ in pycompat.xrange(pick(filesremoved)):
                for __ in pycompat.xrange(10):
                    path = random.choice(mfk)
                    if path not in changes:
                        break
        if filesadded:
            dirs = list(pctx.dirs())
            dirs.insert(0, '')
        for __ in pycompat.xrange(pick(filesadded)):
            pathstr = ''
            while pathstr in dirs:
                path = [random.choice(dirs)]
                if pick(dirsadded):
                    path.append(random.choice(words))
                path.append(random.choice(words))
                pathstr = '/'.join(filter(None, path))
            data = (
                '\n'.join(
                    makeline()
                    for __ in pycompat.xrange(pick(linesinfilesadded))
                )
                + '\n'
            )
            changes[pathstr] = data

        def filectxfn(repo, memctx, path):
            if path not in changes:
                return None
            return context.memfilectx(repo, memctx, path, changes[path])

        if not changes:
            continue
        if revs:
            date = repo['tip'].date()[0] + pick(interarrival)
        else:
            date = time.time() - (86400 * count)
        # dates in mercurial must be positive, fit in 32-bit signed integers.
        date = min(0x7FFFFFFF, max(0, date))
        user = random.choice(words) + '@' + random.choice(words)
        mc = context.memctx(
            repo,
            pl,
            makeline(minimum=2),
            sorted(changes),
            filectxfn,
            user,
            '%d %d' % (date, pick(tzoffset)),
        )
        newnode = mc.commit()
        heads.add(repo.changelog.rev(newnode))
        heads.discard(r1)
        heads.discard(r2)
    progress.complete()

    lock.release()
    wlock.release()


def renamedirs(dirs, words):
    '''Randomly rename the directory names in the per-dir file count dict.'''
    wordgen = itertools.cycle(words)
    replacements = {'': ''}

    def rename(dirpath):
        '''Recursively rename the directory and all path prefixes.

        The mapping from path to renamed path is stored for all path prefixes
        as in dynamic programming, ensuring linear runtime and consistent
        renaming regardless of iteration order through the model.
        '''
        if dirpath in replacements:
            return replacements[dirpath]
        head, _ = os.path.split(dirpath)
        if head:
            head = rename(head)
        else:
            head = ''
        renamed = os.path.join(head, next(wordgen))
        replacements[dirpath] = renamed
        return renamed

    result = []
    for dirpath, count in dirs.iteritems():
        result.append([rename(dirpath.lstrip(os.sep)), count])
    return result