view contrib/shrink-revlog.py @ 12536:208fc9ad6a48

alias: only allow global options before a shell alias, pass later ones through

This patch refactors the dispatch code to change how arguments to shell aliases
are handled.

A separate "pass" to determine whether a command is a shell alias has been
added. The rough steps dispatch now performs when a command is given are these:

* Parse all arguments up to the command name.

* If any arguments such as --repository or --cwd are given (which could change
  the config file used, and therefore the definition of aliases), they are
  taken into account.

* We determine whether the command is a shell alias.

    * If so, execute the alias. The --repo and --cwd arguments are still in effect.
      Any arguments *after* the command name are passed unchanged through to the
      shell command (and interpolated as normal.

    * If the command is *not* a shell alias, the dispatching is effectively "reset"
      and reparsed as normal in its entirety.

The net effect of this patch is to make shell alias commands behave as you
would expect.

Any arguments you give to a shell alias *after* the alias name are passed
through unchanged. This lets you do something like the following:

    [alias]
    filereleased = !$HG log -r 'descendants(adds("$1")) and tagged()' -l1 $2 $3 $4 $5

    $ hg filereleased hgext/bookmarks.py --style compact

Previously the `--style compact` part would fail because Mercurial would
interpret those arguments as arguments to the alias command itself (which
doesn't take any arguments).

Also: running something like `hg -R ~/src/hg-crew filereleased
hgext/bookmarks.py` when `filereleased` is only defined in that repo's config
will now work.

These global arguments can *only* be given to a shell alias *before* the alias
name.  For example, this will *not* work in the above situation:

    $ hg filereleased -R ~/src/hg-crew hgext/bookmarks.py

The reason for this is that you may want to pass arguments like --repository to
the alias (or, more likely, their short versions like -R):

    [alias]
    own = !chown $@ `$HG root`

    $ hg own steve
    $ hg own -R steve

#!/usr/bin/env python

"""\
reorder a revlog (the manifest by default) to save space

Specifically, this topologically sorts the revisions in the revlog so that
revisions on the same branch are adjacent as much as possible. This is a
workaround for the fact that Mercurial computes deltas relative to the
previous revision rather than relative to a parent revision.

This is *not* safe to run on a changelog.
"""

# Originally written by Benoit Boissinot <benoit.boissinot at ens-lyon.org>
# as a patch to rewrite-log. Cleaned up, refactored, documented, and
# renamed by Greg Ward <greg at gerg.ca>.

# XXX would be nice to have a way to verify the repository after shrinking,
# e.g. by comparing "before" and "after" states of random changesets
# (maybe: export before, shrink, export after, diff).

import os, tempfile, errno
from mercurial import revlog, transaction, node, util
from mercurial import changegroup
from mercurial.i18n import _


def postorder(start, edges):
    result = []
    visit = list(start)
    finished = set()

    while visit:
        cur = visit[-1]
        for p in edges[cur]:
            if p not in finished:
                visit.append(p)
                break
        else:
            result.append(cur)
            finished.add(cur)
            visit.pop()

    return result

def toposort_reversepostorder(ui, rl):
    # postorder of the reverse directed graph

    # map rev to list of parent revs (p2 first)
    parents = {}
    heads = set()
    ui.status(_('reading revs\n'))
    try:
        for rev in rl:
            ui.progress(_('reading'), rev, total=len(rl))
            (p1, p2) = rl.parentrevs(rev)
            if p1 == p2 == node.nullrev:
                parents[rev] = ()       # root node
            elif p1 == p2 or p2 == node.nullrev:
                parents[rev] = (p1,)    # normal node
            else:
                parents[rev] = (p2, p1) # merge node
            heads.add(rev)
            for p in parents[rev]:
                heads.discard(p)
    finally:
        ui.progress(_('reading'), None)

    heads = list(heads)
    heads.sort(reverse=True)

    ui.status(_('sorting revs\n'))
    return postorder(heads, parents)

def toposort_postorderreverse(ui, rl):
    # reverse-postorder of the reverse directed graph

    children = {}
    roots = set()
    ui.status(_('reading revs\n'))
    try:
        for rev in rl:
            ui.progress(_('reading'), rev, total=len(rl))
            (p1, p2) = rl.parentrevs(rev)
            if p1 == p2 == node.nullrev:
                roots.add(rev)
            children[rev] = []
            if p1 != node.nullrev:
                children[p1].append(rev)
            if p2 != node.nullrev:
                children[p2].append(rev)
    finally:
        ui.progress(_('reading'), None)

    roots = list(roots)
    roots.sort()

    ui.status(_('sorting revs\n'))
    result = postorder(roots, children)
    result.reverse()
    return result

def writerevs(ui, r1, r2, order, tr):

    ui.status(_('writing revs\n'))

    count = [0]
    def progress(*args):
        ui.progress(_('writing'), count[0], total=len(order))
        count[0] += 1

    order = [r1.node(r) for r in order]

    # this is a bit ugly, but it works
    lookup = lambda x: "%020d" % r1.linkrev(r1.rev(x))
    unlookup = lambda x: int(x, 10)

    try:
        group = util.chunkbuffer(r1.group(order, lookup, progress))
        group = changegroup.unbundle10(group, "UN")
        r2.addgroup(group, unlookup, tr)
    finally:
        ui.progress(_('writing'), None)

def report(ui, r1, r2):
    def getsize(r):
        s = 0
        for fn in (r.indexfile, r.datafile):
            try:
                s += os.stat(fn).st_size
            except OSError, inst:
                if inst.errno != errno.ENOENT:
                    raise
        return s

    oldsize = float(getsize(r1))
    newsize = float(getsize(r2))

    # argh: have to pass an int to %d, because a float >= 2^32
    # blows up under Python 2.5 or earlier
    ui.write(_('old file size: %12d bytes (%6.1f MiB)\n')
             % (int(oldsize), oldsize / 1024 / 1024))
    ui.write(_('new file size: %12d bytes (%6.1f MiB)\n')
             % (int(newsize), newsize / 1024 / 1024))

    shrink_percent = (oldsize - newsize) / oldsize * 100
    shrink_factor = oldsize / newsize
    ui.write(_('shrinkage: %.1f%% (%.1fx)\n')
             % (shrink_percent, shrink_factor))

def shrink(ui, repo, **opts):
    """shrink a revlog by reordering revisions

    Rewrites all the entries in some revlog of the current repository
    (by default, the manifest log) to save space.

    Different sort algorithms have different performance
    characteristics.  Use ``--sort`` to select a sort algorithm so you
    can determine which works best for your data.
    """

    if not repo.local():
        raise util.Abort(_('not a local repository: %s') % repo.root)

    fn = opts.get('revlog')
    if not fn:
        indexfn = repo.sjoin('00manifest.i')
    else:
        if not fn.endswith('.i'):
            raise util.Abort(_('--revlog option must specify the revlog index '
                               'file (*.i), not %s') % opts.get('revlog'))

        indexfn = os.path.realpath(fn)
        store = repo.sjoin('')
        if not indexfn.startswith(store):
            raise util.Abort(_('--revlog option must specify a revlog in %s, '
                               'not %s') % (store, indexfn))

    sortname = opts['sort']
    try:
        toposort = globals()['toposort_' + sortname]
    except KeyError:
        raise util.Abort(_('no such toposort algorithm: %s') % sortname)

    if not os.path.exists(indexfn):
        raise util.Abort(_('no such file: %s') % indexfn)
    if '00changelog' in indexfn:
        raise util.Abort(_('shrinking the changelog '
                           'will corrupt your repository'))

    ui.write(_('shrinking %s\n') % indexfn)
    prefix = os.path.basename(indexfn)[:-1]
    tmpindexfn = util.mktempcopy(indexfn, emptyok=True)

    r1 = revlog.revlog(util.opener(os.getcwd(), audit=False), indexfn)
    r2 = revlog.revlog(util.opener(os.getcwd(), audit=False), tmpindexfn)

    datafn, tmpdatafn = r1.datafile, r2.datafile

    oldindexfn = indexfn + '.old'
    olddatafn = datafn + '.old'
    if os.path.exists(oldindexfn) or os.path.exists(olddatafn):
        raise util.Abort(_('one or both of\n'
                           '  %s\n'
                           '  %s\n'
                           'exists from a previous run; please clean up '
                           'before running again') % (oldindexfn, olddatafn))

    # Don't use repo.transaction(), because then things get hairy with
    # paths: some need to be relative to .hg, and some need to be
    # absolute. Doing it this way keeps things simple: everything is an
    # absolute path.
    lock = repo.lock(wait=False)
    tr = transaction.transaction(ui.warn,
                                 open,
                                 repo.sjoin('journal'))

    def ignoremissing(func):
        def f(*args, **kw):
            try:
                return func(*args, **kw)
            except OSError, inst:
                if inst.errno != errno.ENOENT:
                    raise
        return f

    try:
        try:
            order = toposort(ui, r1)

            suboptimal = 0
            for i in xrange(1, len(order)):
                parents = [p for p in r1.parentrevs(order[i])
                           if p != node.nullrev]
                if parents and order[i - 1] not in parents:
                    suboptimal += 1
            ui.note(_('%d suboptimal nodes\n') % suboptimal)

            writerevs(ui, r1, r2, order, tr)
            report(ui, r1, r2)
            tr.close()
        except:
            # Abort transaction first, so we truncate the files before
            # deleting them.
            tr.abort()
            for fn in (tmpindexfn, tmpdatafn):
                ignoremissing(os.unlink)(fn)
            raise
        if not opts.get('dry_run'):
            # racy, both files cannot be renamed atomically
            # copy files
            util.os_link(indexfn, oldindexfn)
            ignoremissing(util.os_link)(datafn, olddatafn)

            # rename
            util.rename(tmpindexfn, indexfn)
            try:
                os.chmod(tmpdatafn, os.stat(datafn).st_mode)
                util.rename(tmpdatafn, datafn)
            except OSError, inst:
                if inst.errno != errno.ENOENT:
                    raise
                ignoremissing(os.unlink)(datafn)
        else:
            for fn in (tmpindexfn, tmpdatafn):
                ignoremissing(os.unlink)(fn)
    finally:
        lock.release()

    if not opts.get('dry_run'):
        ui.write(_('note: old revlog saved in:\n'
                   '  %s\n'
                   '  %s\n'
                   '(You can delete those files when you are satisfied that your\n'
                   'repository is still sane.  '
                   'Running \'hg verify\' is strongly recommended.)\n')
                 % (oldindexfn, olddatafn))

cmdtable = {
    'shrink': (shrink,
               [('', 'revlog', '', _('index (.i) file of the revlog to shrink')),
                ('n', 'dry-run', None, _('do not shrink, simulate only')),
                ('', 'sort', 'reversepostorder', 'name of sort algorithm to use'),
                ],
               _('hg shrink [--revlog PATH]'))
}

if __name__ == "__main__":
    print "shrink-revlog.py is now an extension (see hg help extensions)"