# 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

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