annotate mercurial/pathutil.py @ 27015:341cb90ffd18

util: disable floating point stat times (issue4836)

Alternate fix for this issue which avoids putting extra function calls
and exception handling in the fast path.

For almost all purposes, integer timestamps are preferable to
Mercurial. It stores integer timestamps in the dirstate and would thus
like to avoid doing any float/int comparisons or conversions. We will
continue to have to deal with 1-second granularity on filesystems for
quite some time, so this won't significantly hinder our capabilities.

This has some impact on our file cache validation code in that it
lowers timestamp resolution. But as we still have to deal with
low-resolution filesystems, we're not relying on this anyway.

An alternate approach is to use stat[ST_MTIME], which is guaranteed to
be an integer. But since this support isn't already in our extension,
we can't depend on it being available without adding a hard Python->C
API dependency that's painful for people like yours truly who have
bisect regularly and people without compilers.

from __future__ import absolute_import

import errno
import os
import posixpath
import stat

from .i18n import _
from . import (
    encoding,
    error,
    util,
)

def _lowerclean(s):
    return encoding.hfsignoreclean(s.lower())

class pathauditor(object):
    '''ensure that a filesystem path contains no banned components.
    the following properties of a path are checked:

    - ends with a directory separator
    - under top-level .hg
    - starts at the root of a windows drive
    - contains ".."
    - traverses a symlink (e.g. a/symlink_here/b)
    - inside a nested repository (a callback can be used to approve
      some nested repositories, e.g., subrepositories)
    '''

    def __init__(self, root, callback=None):
        self.audited = set()
        self.auditeddir = set()
        self.root = root
        self.callback = callback
        if os.path.lexists(root) and not util.checkcase(root):
            self.normcase = util.normcase
        else:
            self.normcase = lambda x: x

    def __call__(self, path):
        '''Check the relative path.
        path may contain a pattern (e.g. foodir/**.txt)'''

        path = util.localpath(path)
        normpath = self.normcase(path)
        if normpath in self.audited:
            return
        # AIX ignores "/" at end of path, others raise EISDIR.
        if util.endswithsep(path):
            raise error.Abort(_("path ends in directory separator: %s") % path)
        parts = util.splitpath(path)
        if (os.path.splitdrive(path)[0]
            or _lowerclean(parts[0]) in ('.hg', '.hg.', '')
            or os.pardir in parts):
            raise error.Abort(_("path contains illegal component: %s") % path)
        # Windows shortname aliases
        for p in parts:
            if "~" in p:
                first, last = p.split("~", 1)
                if last.isdigit() and first.upper() in ["HG", "HG8B6C"]:
                    raise error.Abort(_("path contains illegal component: %s")
                                     % path)
        if '.hg' in _lowerclean(path):
            lparts = [_lowerclean(p.lower()) for p in parts]
            for p in '.hg', '.hg.':
                if p in lparts[1:]:
                    pos = lparts.index(p)
                    base = os.path.join(*parts[:pos])
                    raise error.Abort(_("path '%s' is inside nested repo %r")
                                     % (path, base))

        normparts = util.splitpath(normpath)
        assert len(parts) == len(normparts)

        parts.pop()
        normparts.pop()
        prefixes = []
        while parts:
            prefix = os.sep.join(parts)
            normprefix = os.sep.join(normparts)
            if normprefix in self.auditeddir:
                break
            curpath = os.path.join(self.root, prefix)
            try:
                st = os.lstat(curpath)
            except OSError as err:
                # EINVAL can be raised as invalid path syntax under win32.
                # They must be ignored for patterns can be checked too.
                if err.errno not in (errno.ENOENT, errno.ENOTDIR, errno.EINVAL):
                    raise
            else:
                if stat.S_ISLNK(st.st_mode):
                    raise error.Abort(
                        _('path %r traverses symbolic link %r')
                        % (path, prefix))
                elif (stat.S_ISDIR(st.st_mode) and
                      os.path.isdir(os.path.join(curpath, '.hg'))):
                    if not self.callback or not self.callback(curpath):
                        raise error.Abort(_("path '%s' is inside nested "
                                           "repo %r")
                                         % (path, prefix))
            prefixes.append(normprefix)
            parts.pop()
            normparts.pop()

        self.audited.add(normpath)
        # only add prefixes to the cache after checking everything: we don't
        # want to add "foo/bar/baz" before checking if there's a "foo/.hg"
        self.auditeddir.update(prefixes)

    def check(self, path):
        try:
            self(path)
            return True
        except (OSError, error.Abort):
            return False

def canonpath(root, cwd, myname, auditor=None):
    '''return the canonical path of myname, given cwd and root'''
    if util.endswithsep(root):
        rootsep = root
    else:
        rootsep = root + os.sep
    name = myname
    if not os.path.isabs(name):
        name = os.path.join(root, cwd, name)
    name = os.path.normpath(name)
    if auditor is None:
        auditor = pathauditor(root)
    if name != rootsep and name.startswith(rootsep):
        name = name[len(rootsep):]
        auditor(name)
        return util.pconvert(name)
    elif name == root:
        return ''
    else:
        # Determine whether `name' is in the hierarchy at or beneath `root',
        # by iterating name=dirname(name) until that causes no change (can't
        # check name == '/', because that doesn't work on windows). The list
        # `rel' holds the reversed list of components making up the relative
        # file name we want.
        rel = []
        while True:
            try:
                s = util.samefile(name, root)
            except OSError:
                s = False
            if s:
                if not rel:
                    # name was actually the same as root (maybe a symlink)
                    return ''
                rel.reverse()
                name = os.path.join(*rel)
                auditor(name)
                return util.pconvert(name)
            dirname, basename = util.split(name)
            rel.append(basename)
            if dirname == name:
                break
            name = dirname

        # A common mistake is to use -R, but specify a file relative to the repo
        # instead of cwd.  Detect that case, and provide a hint to the user.
        hint = None
        try:
            if cwd != root:
                canonpath(root, root, myname, auditor)
                hint = (_("consider using '--cwd %s'")
                        % os.path.relpath(root, cwd))
        except error.Abort:
            pass

        raise error.Abort(_("%s not under root '%s'") % (myname, root),
                         hint=hint)

def normasprefix(path):
    '''normalize the specified path as path prefix

    Returned value can be used safely for "p.startswith(prefix)",
    "p[len(prefix):]", and so on.

    For efficiency, this expects "path" argument to be already
    normalized by "os.path.normpath", "os.path.realpath", and so on.

    See also issue3033 for detail about need of this function.

    >>> normasprefix('/foo/bar').replace(os.sep, '/')
    '/foo/bar/'
    >>> normasprefix('/').replace(os.sep, '/')
    '/'
    '''
    d, p = os.path.splitdrive(path)
    if len(p) != len(os.sep):
        return path + os.sep
    else:
        return path

# forward two methods from posixpath that do what we need, but we'd
# rather not let our internals know that we're thinking in posix terms
# - instead we'll let them be oblivious.
join = posixpath.join
dirname = posixpath.dirname