VirtualMailManager/common.py
author martin f. krafft <madduck@madduck.net>
Mon, 09 Apr 2012 18:10:56 +0200
branchv0.6.x
changeset 504 f180ead60568
parent 414 ae1a8428298c
child 527 e09139525580
permissions -rw-r--r--
First version of a CatchallAlias class I based the CatchallAlias class in catchall.py heavily on the Alias class, but by copy, not deriving. The two are functionally related, but the implementations are too different because CatchallAliases have no localpart.

# -*- coding: UTF-8 -*-
# Copyright (c) 2010 - 2011, Pascal Volk
# See COPYING for distribution information.
"""
    VirtualMailManager.common
    ~~~~~~~~~~~~~~~~~~~~~~~~~

    Some common functions
"""

import locale
import os
import re
import stat

from VirtualMailManager import ENCODING
from VirtualMailManager.constants import NOT_EXECUTABLE, NO_SUCH_BINARY
from VirtualMailManager.errors import VMMError


VERSION_RE = re.compile(r'^(\d+)\.(\d+)\.(?:(\d+)|(alpha|beta|rc)(\d+))$')

_version_level = dict(alpha=0xA, beta=0xB, rc=0xC)
_version_cache = {}
_ = lambda msg: msg


def expand_path(path):
    """Expands paths, starting with ``.`` or ``~``, to an absolute path."""
    if path.startswith('.'):
        return os.path.abspath(path)
    if path.startswith('~'):
        return os.path.expanduser(path)
    return path


def get_unicode(string):
    """Converts `string` to `unicode`, if necessary."""
    if isinstance(string, unicode):
        return string
    return unicode(string, ENCODING, 'replace')


def lisdir(path):
    """Checks if `path` is a directory.  Doesn't follow symbolic links.
    Returns bool.
    """
    try:
        lstat = os.lstat(path)
    except OSError:
        return False
    return stat.S_ISDIR(lstat.st_mode)


def exec_ok(binary):
    """Checks if the `binary` exists and if it is executable.

    Throws a `VMMError` if the `binary` isn't a file or is not
    executable.
    """
    binary = expand_path(binary)
    if not os.path.isfile(binary):
        raise VMMError(_(u"No such file: '%s'") % get_unicode(binary),
                       NO_SUCH_BINARY)
    if not os.access(binary, os.X_OK):
        raise VMMError(_(u"File is not executable: '%s'") %
                       get_unicode(binary), NOT_EXECUTABLE)
    return binary


def human_size(size):
    """Converts the `size` in bytes in human readable format."""
    if not isinstance(size, (long, int)):
        try:
            size = long(size)
        except ValueError:
            raise TypeError("'size' must be a positive long or int.")
    if size < 0:
        raise ValueError("'size' must be a positive long or int.")
    if size < 1024:
        return str(size)
    prefix_multiply = ((_(u'TiB'), 1 << 40), (_(u'GiB'), 1 << 30),
                       (_(u'MiB'), 1 << 20), (_(u'KiB'), 1 << 10))
    for prefix, multiply in prefix_multiply:
        if size >= multiply:
            # TP: e.g.: '%(size)s %(prefix)s' -> '118.30 MiB'
            return _(u'%(size)s %(prefix)s') % {
                    'size': locale.format('%.2f', float(size) / multiply,
                                          True),
                    'prefix': prefix}


def size_in_bytes(size):
    """Converts the string `size` to a long (size in bytes).

    The string `size` can be suffixed with *b* (bytes), *k* (kilobytes),
    *M* (megabytes) or *G* (gigabytes).
    """
    if not isinstance(size, basestring) or not size:
        raise TypeError('size must be a non empty string.')
    if size[-1].upper() in ('B', 'K', 'M', 'G'):
        try:
            num = int(size[:-1])
        except ValueError:
            raise ValueError('Not a valid integer value: %r' % size[:-1])
        unit = size[-1].upper()
        if unit == 'B':
            return num
        elif unit == 'K':
            return num << 10L
        elif unit == 'M':
            return num << 20L
        else:
            return num << 30L
    else:
        try:
            num = int(size)
        except ValueError:
            raise ValueError('Not a valid size value: %r' % size)
        return num


def version_hex(version_string):
    """Converts a Dovecot version, e.g.: '1.2.3' or '2.0.beta4', to an int.
    Raises a `ValueError` if the *version_string* has the wrong™ format.

    version_hex('1.2.3') -> 270548736
    hex(version_hex('1.2.3')) -> '0x10203f00'
    """
    global _version_cache
    if version_string in _version_cache:
        return _version_cache[version_string]
    version = 0
    version_mo = VERSION_RE.match(version_string)
    if not version_mo:
        raise ValueError('Invalid version string: %r' % version_string)
    major, minor, patch, level, serial = version_mo.groups()
    major = int(major)
    minor = int(minor)
    if patch:
        patch = int(patch)
    if serial:
        serial = int(serial)

    if major > 0xFF or minor > 0xFF or \
      patch and patch > 0xFF or serial and serial > 0xFF:
        raise ValueError('Invalid version string: %r' % version_string)

    version += major << 28
    version += minor << 20
    if patch:
        version += patch << 12
    version += _version_level.get(level, 0xF) << 8
    if serial:
        version += serial

    _version_cache[version_string] = version
    return version


def version_str(version):
    """Converts a Dovecot version previously converted with version_hex back to
    a string.
    Raises a `TypeError` if *version* is not an int/long.
    Raises a `ValueError` if *version* is an incorrect int version.
    """
    global _version_cache
    if version in _version_cache:
        return _version_cache[version]
    if not isinstance(version, (int, long)):
        raise TypeError('Argument is not a int/long: %r', version)
    major = (version >> 28) & 0xFF
    minor = (version >> 20) & 0xFF
    patch = (version >> 12) & 0xFF
    level = (version >> 8) & 0x0F
    serial = version & 0xFF

    levels = dict(zip(_version_level.values(), _version_level.keys()))
    if level == 0xF and not serial:
        version_string = '%u.%u.%u' % (major, minor, patch)
    elif level in levels and not patch:
        version_string = '%u.%u.%s%u' % (major, minor, levels[level], serial)
    else:
        raise ValueError('Invalid version: %r' % hex(version))

    _version_cache[version] = version_string
    return version_string

del _