mercurial/sparse.py

sparse: move function for resolving sparse matcher into core

As part of the move, the function arguments changed so revs are
passed as a list instead of *args. This allows us to use keyword
arguments properly.

Since the plan is to integrate sparse into core and have it
enabled by default, we need to prepare for a sparse matcher
to always be obtained and operated on. As part of the move,
we inserted code that returns an always matcher if sparse
isn't enabled. Some callers in the sparse extension take this
into account and conditionally perform matching depending on
whether the special always matcher is seen. I /think/ this
may have sped up some operations where the extension is
installed but no sparse config is activated.

One thing I'm ensure of in this code is whether os.path.dirname()
is semantically correct. os.posixpath.dirname() (which is
exported as pathutil.dirname) might be a better choise because
all patterns should be using posix directory separators (/)
instead of Windows (\). There's an inline comment that implies
Windows was tested. So hopefully it won't be a problem. We
can improve this in a follow-up. I've added a TODO to track it.

# sparse.py - functionality for sparse checkouts
#
# Copyright 2014 Facebook, Inc.
#
# 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 hashlib
import os

from .i18n import _
from .node import nullid
from . import (
    error,
    match as matchmod,
    pycompat,
)

# Whether sparse features are enabled. This variable is intended to be
# temporary to facilitate porting sparse to core. It should eventually be
# a per-repo option, possibly a repo requirement.
enabled = False

def parseconfig(ui, raw):
    """Parse sparse config file content.

    Returns a tuple of includes, excludes, and profiles.
    """
    includes = set()
    excludes = set()
    current = includes
    profiles = []
    for line in raw.split('\n'):
        line = line.strip()
        if not line or line.startswith('#'):
            # empty or comment line, skip
            continue
        elif line.startswith('%include '):
            line = line[9:].strip()
            if line:
                profiles.append(line)
        elif line == '[include]':
            if current != includes:
                # TODO pass filename into this API so we can report it.
                raise error.Abort(_('sparse config cannot have includes ' +
                                    'after excludes'))
            continue
        elif line == '[exclude]':
            current = excludes
        elif line:
            if line.strip().startswith('/'):
                ui.warn(_('warning: sparse profile cannot use' +
                          ' paths starting with /, ignoring %s\n') % line)
                continue
            current.add(line)

    return includes, excludes, profiles

# Exists as separate function to facilitate monkeypatching.
def readprofile(repo, profile, changeid):
    """Resolve the raw content of a sparse profile file."""
    # TODO add some kind of cache here because this incurs a manifest
    # resolve and can be slow.
    return repo.filectx(profile, changeid=changeid).data()

def patternsforrev(repo, rev):
    """Obtain sparse checkout patterns for the given rev.

    Returns a tuple of iterables representing includes, excludes, and
    patterns.
    """
    # Feature isn't enabled. No-op.
    if not enabled:
        return set(), set(), []

    raw = repo.vfs.tryread('sparse')
    if not raw:
        return set(), set(), []

    if rev is None:
        raise error.Abort(_('cannot parse sparse patterns from working '
                            'directory'))

    includes, excludes, profiles = parseconfig(repo.ui, raw)
    ctx = repo[rev]

    if profiles:
        visited = set()
        while profiles:
            profile = profiles.pop()
            if profile in visited:
                continue

            visited.add(profile)

            try:
                raw = readprofile(repo, profile, rev)
            except error.ManifestLookupError:
                msg = (
                    "warning: sparse profile '%s' not found "
                    "in rev %s - ignoring it\n" % (profile, ctx))
                # experimental config: sparse.missingwarning
                if repo.ui.configbool(
                        'sparse', 'missingwarning', True):
                    repo.ui.warn(msg)
                else:
                    repo.ui.debug(msg)
                continue

            pincludes, pexcludes, subprofs = parseconfig(repo.ui, raw)
            includes.update(pincludes)
            excludes.update(pexcludes)
            for subprofile in subprofs:
                profiles.append(subprofile)

        profiles = visited

    if includes:
        includes.add('.hg*')

    return includes, excludes, profiles

def activeprofiles(repo):
    revs = [repo.changelog.rev(node) for node in
            repo.dirstate.parents() if node != nullid]

    profiles = set()
    for rev in revs:
        profiles.update(patternsforrev(repo, rev)[2])

    return profiles

def invalidatesignaturecache(repo):
    repo._sparsesignaturecache.clear()

def configsignature(repo, includetemp=True):
    """Obtain the signature string for the current sparse configuration.

    This is used to construct a cache key for matchers.
    """
    cache = repo._sparsesignaturecache

    signature = cache.get('signature')

    if includetemp:
        tempsignature = cache.get('tempsignature')
    else:
        tempsignature = '0'

    if signature is None or (includetemp and tempsignature is None):
        signature = hashlib.sha1(repo.vfs.tryread('sparse')).hexdigest()
        cache['signature'] = signature

        if includetemp:
            raw = repo.vfs.tryread('tempsparse')
            tempsignature = hashlib.sha1(raw).hexdigest()
            cache['tempsignature'] = tempsignature

    return '%s %s' % (signature, tempsignature)

def writeconfig(repo, includes, excludes, profiles):
    """Write the sparse config file given a sparse configuration."""
    with repo.vfs('sparse', 'wb') as fh:
        for p in sorted(profiles):
            fh.write('%%include %s\n' % p)

        if includes:
            fh.write('[include]\n')
            for i in sorted(includes):
                fh.write(i)
                fh.write('\n')

        if excludes:
            fh.write('[exclude]\n')
            for e in sorted(excludes):
                fh.write(e)
                fh.write('\n')

    invalidatesignaturecache(repo)

def readtemporaryincludes(repo):
    raw = repo.vfs.tryread('tempsparse')
    if not raw:
        return set()

    return set(raw.split('\n'))

def writetemporaryincludes(repo, includes):
    repo.vfs.write('tempsparse', '\n'.join(sorted(includes)))
    invalidatesignaturecache(repo)

def addtemporaryincludes(repo, additional):
    includes = readtemporaryincludes(repo)
    for i in additional:
        includes.add(i)
    writetemporaryincludes(repo, includes)

def matcher(repo, revs=None, includetemp=True):
    """Obtain a matcher for sparse working directories for the given revs.

    If multiple revisions are specified, the matcher is the union of all
    revs.

    ``includetemp`` indicates whether to use the temporary sparse profile.
    """
    # If sparse isn't enabled, sparse matcher matches everything.
    if not enabled:
        return matchmod.always(repo.root, '')

    if not revs or revs == [None]:
        revs = [repo.changelog.rev(node)
                for node in repo.dirstate.parents() if node != nullid]

    signature = configsignature(repo, includetemp=includetemp)

    key = '%s %s' % (signature, ' '.join(map(pycompat.bytestr, revs)))

    result = repo._sparsematchercache.get(key)
    if result:
        return result

    matchers = []
    for rev in revs:
        try:
            includes, excludes, profiles = patternsforrev(repo, rev)

            if includes or excludes:
                # Explicitly include subdirectories of includes so
                # status will walk them down to the actual include.
                subdirs = set()
                for include in includes:
                    # TODO consider using posix path functions here so Windows
                    # \ directory separators don't come into play.
                    dirname = os.path.dirname(include)
                    # basename is used to avoid issues with absolute
                    # paths (which on Windows can include the drive).
                    while os.path.basename(dirname):
                        subdirs.add(dirname)
                        dirname = os.path.dirname(dirname)

                matcher = matchmod.match(repo.root, '', [],
                                         include=includes, exclude=excludes,
                                         default='relpath')
                if subdirs:
                    matcher = matchmod.forceincludematcher(matcher, subdirs)
                matchers.append(matcher)
        except IOError:
            pass

    if not matchers:
        result = matchmod.always(repo.root, '')
    elif len(matchers) == 1:
        result = matchers[0]
    else:
        result = matchmod.unionmatcher(matchers)

    if includetemp:
        tempincludes = readtemporaryincludes(repo)
        result = matchmod.forceincludematcher(result, tempincludes)

    repo._sparsematchercache[key] = result

    return result