# scmutil.py - Mercurial core utility functions

#

#  Copyright Matt Mackall <mpm@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from i18n import _

import util, error

import os, errno, stat

def checkportable(ui, f):

    '''Check if filename f is portable and warn or abort depending on config'''

    val = ui.config('ui', 'portablefilenames', 'warn')

    lval = val.lower()

    abort = os.name == 'nt' or lval == 'abort'

    bval = util.parsebool(val)

    if abort or lval == 'warn' or bval:

        msg = util.checkwinfilename(f)

        if msg:

            if abort:

                raise util.Abort("%s: %r" % (msg, f))

            ui.warn(_("warning: %s: %r\n") % (msg, f))

    elif bval is None and lval != 'ignore':

        raise error.ConfigError(

            _("ui.portablefilenames value is invalid ('%s')") % val)

class path_auditor(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

    def __call__(self, path):

        '''Check the relative path.

        path may contain a pattern (e.g. foodir/**.txt)'''

        if path in self.audited:

            return

        # AIX ignores "/" at end of path, others raise EISDIR.

        if util.endswithsep(path):

            raise util.Abort(_("path ends in directory separator: %s") % path)

        normpath = os.path.normcase(path)

        parts = util.splitpath(normpath)

        if (os.path.splitdrive(path)[0]

            or parts[0].lower() in ('.hg', '.hg.', '')

            or os.pardir in parts):

            raise util.Abort(_("path contains illegal component: %s") % path)

        if '.hg' in path.lower():

            lparts = [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 util.Abort(_('path %r is inside nested repo %r')

                                     % (path, base))

        parts.pop()

        prefixes = []

        while parts:

            prefix = os.sep.join(parts)

            if prefix in self.auditeddir:

                break

            curpath = os.path.join(self.root, prefix)

            try:

                st = os.lstat(curpath)

            except OSError, 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 util.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 util.Abort(_('path %r is inside nested repo %r') %

                                         (path, prefix))

            prefixes.append(prefix)

            parts.pop()

        self.audited.add(path)

        # 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)

class opener(object):

    '''Open files relative to a base directory

    This class is used to hide the details of COW semantics and

    remote file access from higher level code.

    '''

    def __init__(self, base, audit=True):

        self.base = base

        if audit:

            self.auditor = path_auditor(base)

        else:

            self.auditor = util.always

        self.createmode = None

        self._trustnlink = None

    @util.propertycache

    def _can_symlink(self):

        return util.checklink(self.base)

    def _fixfilemode(self, name):

        if self.createmode is None:

            return

        os.chmod(name, self.createmode & 0666)

    def __call__(self, path, mode="r", text=False, atomictemp=False):

        r = util.checkosfilename(path)

        if r:

            raise util.Abort("%s: %r" % (r, path))

        self.auditor(path)

        f = os.path.join(self.base, path)

        if not text and "b" not in mode:

            mode += "b" # for that other OS

        nlink = -1

        dirname, basename = os.path.split(f)

        # If basename is empty, then the path is malformed because it points

        # to a directory. Let the posixfile() call below raise IOError.

        if basename and mode not in ('r', 'rb'):

            if atomictemp:

                if not os.path.isdir(dirname):

                    util.makedirs(dirname, self.createmode)

                return util.atomictempfile(f, mode, self.createmode)

            try:

                if 'w' in mode:

                    util.unlink(f)

                    nlink = 0

                else:

                    # nlinks() may behave differently for files on Windows

                    # shares if the file is open.

                    fd = util.posixfile(f)

                    nlink = util.nlinks(f)

                    if nlink < 1:

                        nlink = 2 # force mktempcopy (issue1922)

                    fd.close()

            except (OSError, IOError), e:

                if e.errno != errno.ENOENT:

                    raise

                nlink = 0

                if not os.path.isdir(dirname):

                    util.makedirs(dirname, self.createmode)

            if nlink > 0:

                if self._trustnlink is None:

                    self._trustnlink = nlink > 1 or util.checknlink(f)

                if nlink > 1 or not self._trustnlink:

                    util.rename(util.mktempcopy(f), f)

        fp = util.posixfile(f, mode)

        if nlink == 0:

            self._fixfilemode(f)

        return fp

    def symlink(self, src, dst):

        self.auditor(dst)

        linkname = os.path.join(self.base, dst)

        try:

            os.unlink(linkname)

        except OSError:

            pass

        dirname = os.path.dirname(linkname)

        if not os.path.exists(dirname):

            util.makedirs(dirname, self.createmode)

        if self._can_symlink:

            try:

                os.symlink(src, linkname)

            except OSError, err:

                raise OSError(err.errno, _('could not symlink to %r: %s') %

                              (src, err.strerror), linkname)

        else:

            f = self(dst, "w")

            f.write(src)

            f.close()

            self._fixfilemode(dst)

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 = path_auditor(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).  For each

        # `name', compare dev/inode numbers.  If they match, the list `rel'

        # holds the reversed list of components making up the relative file

        # name we want.

        root_st = os.stat(root)

        rel = []

        while True:

            try:

                name_st = os.stat(name)

            except OSError:

                break

            if util.samestat(name_st, root_st):

                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 = os.path.split(name)

            rel.append(basename)

            if dirname == name:

                break

            name = dirname

        raise util.Abort('%s not under root' % myname)