# 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 checkfilename(f):
    '''Check that the filename f is an acceptable filename for a tracked file'''
    if '\r' in f or '\n' in f:
        raise util.Abort(_("'\\n' and '\\r' disallowed in filenames: %r") % f)

def checkportable(ui, f):
    '''Check if filename f is portable and warn or abort depending on config'''
    checkfilename(f)
    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)

def walkrepos(path, followsym=False, seen_dirs=None, recurse=False):
    '''yield every hg repository under path, recursively.'''
    def errhandler(err):
        if err.filename == path:
            raise err
    if followsym and hasattr(os.path, 'samestat'):
        def _add_dir_if_not_there(dirlst, dirname):
            match = False
            samestat = os.path.samestat
            dirstat = os.stat(dirname)
            for lstdirstat in dirlst:
                if samestat(dirstat, lstdirstat):
                    match = True
                    break
            if not match:
                dirlst.append(dirstat)
            return not match
    else:
        followsym = False

    if (seen_dirs is None) and followsym:
        seen_dirs = []
        _add_dir_if_not_there(seen_dirs, path)
    for root, dirs, files in os.walk(path, topdown=True, onerror=errhandler):
        dirs.sort()
        if '.hg' in dirs:
            yield root # found a repository
            qroot = os.path.join(root, '.hg', 'patches')
            if os.path.isdir(os.path.join(qroot, '.hg')):
                yield qroot # we have a patch queue repo here
            if recurse:
                # avoid recursing inside the .hg directory
                dirs.remove('.hg')
            else:
                dirs[:] = [] # don't descend further
        elif followsym:
            newdirs = []
            for d in dirs:
                fname = os.path.join(root, d)
                if _add_dir_if_not_there(seen_dirs, fname):
                    if os.path.islink(fname):
                        for hgname in walkrepos(fname, True, seen_dirs):
                            yield hgname
                    else:
                        newdirs.append(d)
            dirs[:] = newdirs