view mercurial/mail.py @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

# mail.py - mail sending bits for mercurial
#
# Copyright 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import email
import email.charset
import email.header
import os
import quopri
import smtplib
import socket
import time

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

class STARTTLS(smtplib.SMTP):
    '''Derived class to verify the peer certificate for STARTTLS.

    This class allows to pass any keyword arguments to SSL socket creation.
    '''
    def __init__(self, ui, host=None, **kwargs):
        smtplib.SMTP.__init__(self, **kwargs)
        self._ui = ui
        self._host = host

    def starttls(self, keyfile=None, certfile=None):
        if not self.has_extn("starttls"):
            msg = "STARTTLS extension not supported by server"
            raise smtplib.SMTPException(msg)
        (resp, reply) = self.docmd("STARTTLS")
        if resp == 220:
            self.sock = sslutil.wrapsocket(self.sock, keyfile, certfile,
                                           ui=self._ui,
                                           serverhostname=self._host)
            self.file = smtplib.SSLFakeFile(self.sock)
            self.helo_resp = None
            self.ehlo_resp = None
            self.esmtp_features = {}
            self.does_esmtp = 0
        return (resp, reply)

class SMTPS(smtplib.SMTP):
    '''Derived class to verify the peer certificate for SMTPS.

    This class allows to pass any keyword arguments to SSL socket creation.
    '''
    def __init__(self, ui, keyfile=None, certfile=None, host=None,
                 **kwargs):
        self.keyfile = keyfile
        self.certfile = certfile
        smtplib.SMTP.__init__(self, **kwargs)
        self._host = host
        self.default_port = smtplib.SMTP_SSL_PORT
        self._ui = ui

    def _get_socket(self, host, port, timeout):
        if self.debuglevel > 0:
            self._ui.debug('connect: %r\n' % (host, port))
        new_socket = socket.create_connection((host, port), timeout)
        new_socket = sslutil.wrapsocket(new_socket,
                                        self.keyfile, self.certfile,
                                        ui=self._ui,
                                        serverhostname=self._host)
        self.file = smtplib.SSLFakeFile(new_socket)
        return new_socket

def _smtp(ui):
    '''build an smtp connection and return a function to send mail'''
    local_hostname = ui.config('smtp', 'local_hostname')
    tls = ui.config('smtp', 'tls', 'none')
    # backward compatible: when tls = true, we use starttls.
    starttls = tls == 'starttls' or util.parsebool(tls)
    smtps = tls == 'smtps'
    if (starttls or smtps) and not util.safehasattr(socket, 'ssl'):
        raise error.Abort(_("can't use TLS: Python SSL support not installed"))
    mailhost = ui.config('smtp', 'host')
    if not mailhost:
        raise error.Abort(_('smtp.host not configured - cannot send mail'))
    if smtps:
        ui.note(_('(using smtps)\n'))
        s = SMTPS(ui, local_hostname=local_hostname, host=mailhost)
    elif starttls:
        s = STARTTLS(ui, local_hostname=local_hostname, host=mailhost)
    else:
        s = smtplib.SMTP(local_hostname=local_hostname)
    if smtps:
        defaultport = 465
    else:
        defaultport = 25
    mailport = util.getport(ui.config('smtp', 'port', defaultport))
    ui.note(_('sending mail: smtp host %s, port %d\n') %
            (mailhost, mailport))
    s.connect(host=mailhost, port=mailport)
    if starttls:
        ui.note(_('(using starttls)\n'))
        s.ehlo()
        s.starttls()
        s.ehlo()
    if starttls or smtps:
        ui.note(_('(verifying remote certificate)\n'))
        sslutil.validatesocket(s.sock)
    username = ui.config('smtp', 'username')
    password = ui.config('smtp', 'password')
    if username and not password:
        password = ui.getpass()
    if username and password:
        ui.note(_('(authenticating to mail server as %s)\n') %
                  (username))
        try:
            s.login(username, password)
        except smtplib.SMTPException as inst:
            raise error.Abort(inst)

    def send(sender, recipients, msg):
        try:
            return s.sendmail(sender, recipients, msg)
        except smtplib.SMTPRecipientsRefused as inst:
            recipients = [r[1] for r in inst.recipients.values()]
            raise error.Abort('\n' + '\n'.join(recipients))
        except smtplib.SMTPException as inst:
            raise error.Abort(inst)

    return send

def _sendmail(ui, sender, recipients, msg):
    '''send mail using sendmail.'''
    program = ui.config('email', 'method', 'smtp')
    cmdline = '%s -f %s %s' % (program, util.email(sender),
                               ' '.join(map(util.email, recipients)))
    ui.note(_('sending mail: %s\n') % cmdline)
    fp = util.popen(cmdline, 'w')
    fp.write(msg)
    ret = fp.close()
    if ret:
        raise error.Abort('%s %s' % (
            os.path.basename(program.split(None, 1)[0]),
            util.explainexit(ret)[0]))

def _mbox(mbox, sender, recipients, msg):
    '''write mails to mbox'''
    fp = open(mbox, 'ab+')
    # Should be time.asctime(), but Windows prints 2-characters day
    # of month instead of one. Make them print the same thing.
    date = time.strftime('%a %b %d %H:%M:%S %Y', time.localtime())
    fp.write('From %s %s\n' % (sender, date))
    fp.write(msg)
    fp.write('\n\n')
    fp.close()

def connect(ui, mbox=None):
    '''make a mail connection. return a function to send mail.
    call as sendmail(sender, list-of-recipients, msg).'''
    if mbox:
        open(mbox, 'wb').close()
        return lambda s, r, m: _mbox(mbox, s, r, m)
    if ui.config('email', 'method', 'smtp') == 'smtp':
        return _smtp(ui)
    return lambda s, r, m: _sendmail(ui, s, r, m)

def sendmail(ui, sender, recipients, msg, mbox=None):
    send = connect(ui, mbox=mbox)
    return send(sender, recipients, msg)

def validateconfig(ui):
    '''determine if we have enough config data to try sending email.'''
    method = ui.config('email', 'method', 'smtp')
    if method == 'smtp':
        if not ui.config('smtp', 'host'):
            raise error.Abort(_('smtp specified as email transport, '
                               'but no smtp host configured'))
    else:
        if not util.findexe(method):
            raise error.Abort(_('%r specified as email transport, '
                               'but not in PATH') % method)

def codec2iana(cs):
    ''''''
    cs = email.charset.Charset(cs).input_charset.lower()

    # "latin1" normalizes to "iso8859-1", standard calls for "iso-8859-1"
    if cs.startswith("iso") and not cs.startswith("iso-"):
        return "iso-" + cs[3:]
    return cs

def mimetextpatch(s, subtype='plain', display=False):
    '''Return MIME message suitable for a patch.
    Charset will be detected by first trying to decode as us-ascii, then utf-8,
    and finally the global encodings. If all those fail, fall back to
    ISO-8859-1, an encoding with that allows all byte sequences.
    Transfer encodings will be used if necessary.'''

    cs = ['us-ascii', 'utf-8', encoding.encoding, encoding.fallbackencoding]
    if display:
        return mimetextqp(s, subtype, 'us-ascii')
    for charset in cs:
        try:
            s.decode(charset)
            return mimetextqp(s, subtype, codec2iana(charset))
        except UnicodeDecodeError:
            pass

    return mimetextqp(s, subtype, "iso-8859-1")

def mimetextqp(body, subtype, charset):
    '''Return MIME message.
    Quoted-printable transfer encoding will be used if necessary.
    '''
    enc = None
    for line in body.splitlines():
        if len(line) > 950:
            body = quopri.encodestring(body)
            enc = "quoted-printable"
            break

    msg = email.MIMEText.MIMEText(body, subtype, charset)
    if enc:
        del msg['Content-Transfer-Encoding']
        msg['Content-Transfer-Encoding'] = enc
    return msg

def _charsets(ui):
    '''Obtains charsets to send mail parts not containing patches.'''
    charsets = [cs.lower() for cs in ui.configlist('email', 'charsets')]
    fallbacks = [encoding.fallbackencoding.lower(),
                 encoding.encoding.lower(), 'utf-8']
    for cs in fallbacks: # find unique charsets while keeping order
        if cs not in charsets:
            charsets.append(cs)
    return [cs for cs in charsets if not cs.endswith('ascii')]

def _encode(ui, s, charsets):
    '''Returns (converted) string, charset tuple.
    Finds out best charset by cycling through sendcharsets in descending
    order. Tries both encoding and fallbackencoding for input. Only as
    last resort send as is in fake ascii.
    Caveat: Do not use for mail parts containing patches!'''
    try:
        s.decode('ascii')
    except UnicodeDecodeError:
        sendcharsets = charsets or _charsets(ui)
        for ics in (encoding.encoding, encoding.fallbackencoding):
            try:
                u = s.decode(ics)
            except UnicodeDecodeError:
                continue
            for ocs in sendcharsets:
                try:
                    return u.encode(ocs), ocs
                except UnicodeEncodeError:
                    pass
                except LookupError:
                    ui.warn(_('ignoring invalid sendcharset: %s\n') % ocs)
    # if ascii, or all conversion attempts fail, send (broken) ascii
    return s, 'us-ascii'

def headencode(ui, s, charsets=None, display=False):
    '''Returns RFC-2047 compliant header from given string.'''
    if not display:
        # split into words?
        s, cs = _encode(ui, s, charsets)
        return str(email.header.Header(s, cs))
    return s

def _addressencode(ui, name, addr, charsets=None):
    name = headencode(ui, name, charsets)
    try:
        acc, dom = addr.split('@')
        acc = acc.encode('ascii')
        dom = dom.decode(encoding.encoding).encode('idna')
        addr = '%s@%s' % (acc, dom)
    except UnicodeDecodeError:
        raise error.Abort(_('invalid email address: %s') % addr)
    except ValueError:
        try:
            # too strict?
            addr = addr.encode('ascii')
        except UnicodeDecodeError:
            raise error.Abort(_('invalid local address: %s') % addr)
    return email.Utils.formataddr((name, addr))

def addressencode(ui, address, charsets=None, display=False):
    '''Turns address into RFC-2047 compliant header.'''
    if display or not address:
        return address or ''
    name, addr = email.Utils.parseaddr(address)
    return _addressencode(ui, name, addr, charsets)

def addrlistencode(ui, addrs, charsets=None, display=False):
    '''Turns a list of addresses into a list of RFC-2047 compliant headers.
    A single element of input list may contain multiple addresses, but output
    always has one address per item'''
    if display:
        return [a.strip() for a in addrs if a.strip()]

    result = []
    for name, addr in email.Utils.getaddresses(addrs):
        if name or addr:
            result.append(_addressencode(ui, name, addr, charsets))
    return result

def mimeencode(ui, s, charsets=None, display=False):
    '''creates mime text object, encodes it if needed, and sets
    charset and transfer-encoding accordingly.'''
    cs = 'us-ascii'
    if not display:
        s, cs = _encode(ui, s, charsets)
    return mimetextqp(s, 'plain', cs)

def headdecode(s):
    '''Decodes RFC-2047 header'''
    uparts = []
    for part, charset in email.header.decode_header(s):
        if charset is not None:
            try:
                uparts.append(part.decode(charset))
                continue
            except UnicodeDecodeError:
                pass
        try:
            uparts.append(part.decode('UTF-8'))
            continue
        except UnicodeDecodeError:
            pass
        uparts.append(part.decode('ISO-8859-1'))
    return encoding.unitolocal(u' '.join(uparts))