hgext/zeroconf/__init__.py

inno: replace add_path.exe with a Pascal script

While attempting to build the Inno installer, I was unable to
find a copy of add_path.exe from the source site previously
listed in the docs.

Some quick Googling revealed that achieving this functionality
in native Pascal scripts seems to be preferred these days.

This commit vendors "Modify Path" (fetched from
https://www.legroom.net/software/modpath) and plugs it into
our Inno config file per its instructions.

The existing Inno installer appears to only modify PATH for
the current user (as opposed to at the system level). I've
maintained this behavior with Modify Path. Although it would
be trivial to change or add checkboxes to control the behavior.
I'll leave this as a follow-up.

Differential Revision: https://phab.mercurial-scm.org/D6060

# zeroconf.py - zeroconf support for Mercurial
#
# Copyright 2005-2007 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.
'''discover and advertise repositories on the local network

Zeroconf-enabled repositories will be announced in a network without
the need to configure a server or a service. They can be discovered
without knowing their actual IP address.

To allow other people to discover your repository using run
:hg:`serve` in your repository::

  $ cd test
  $ hg serve

You can discover Zeroconf-enabled repositories by running
:hg:`paths`::

  $ hg paths
  zc-test = http://example.com:8000/test
'''
from __future__ import absolute_import

import os
import socket
import time

from . import Zeroconf
from mercurial import (
    dispatch,
    encoding,
    extensions,
    hg,
    ui as uimod,
)
from mercurial.hgweb import (
    server as servermod
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

# publish

server = None
localip = None

def getip():
    # finds external-facing interface without sending any packets (Linux)
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(('1.0.0.1', 0))
        ip = s.getsockname()[0]
        return ip
    except socket.error:
        pass

    # Generic method, sometimes gives useless results
    try:
        dumbip = socket.gethostbyaddr(socket.gethostname())[2][0]
        if ':' in dumbip:
            dumbip = '127.0.0.1'
        if not dumbip.startswith('127.'):
            return dumbip
    except (socket.gaierror, socket.herror):
        dumbip = '127.0.0.1'

    # works elsewhere, but actually sends a packet
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(('1.0.0.1', 1))
        ip = s.getsockname()[0]
        return ip
    except socket.error:
        pass

    return dumbip

def publish(name, desc, path, port):
    global server, localip
    if not server:
        ip = getip()
        if ip.startswith('127.'):
            # if we have no internet connection, this can happen.
            return
        localip = socket.inet_aton(ip)
        server = Zeroconf.Zeroconf(ip)

    hostname = socket.gethostname().split('.')[0]
    host = hostname + ".local"
    name = "%s-%s" % (hostname, name)

    # advertise to browsers
    svc = Zeroconf.ServiceInfo('_http._tcp.local.',
                               name + '._http._tcp.local.',
                               server = host,
                               port = port,
                               properties = {'description': desc,
                                             'path': "/" + path},
                               address = localip, weight = 0, priority = 0)
    server.registerService(svc)

    # advertise to Mercurial clients
    svc = Zeroconf.ServiceInfo('_hg._tcp.local.',
                               name + '._hg._tcp.local.',
                               server = host,
                               port = port,
                               properties = {'description': desc,
                                             'path': "/" + path},
                               address = localip, weight = 0, priority = 0)
    server.registerService(svc)

def zc_create_server(create_server, ui, app):
    httpd = create_server(ui, app)
    port = httpd.port

    try:
        repos = app.repos
    except AttributeError:
        # single repo
        with app._obtainrepo() as repo:
            name = app.reponame or os.path.basename(repo.root)
            path = repo.ui.config("web", "prefix", "").strip('/')
            desc = repo.ui.config("web", "description")
            if not desc:
                desc = name
        publish(name, desc, path, port)
    else:
        # webdir
        prefix = app.ui.config("web", "prefix", "").strip('/') + '/'
        for repo, path in repos:
            u = app.ui.copy()
            u.readconfig(os.path.join(path, '.hg', 'hgrc'))
            name = os.path.basename(repo)
            path = (prefix + repo).strip('/')
            desc = u.config('web', 'description')
            if not desc:
                desc = name
            publish(name, desc, path, port)
    return httpd

# listen

class listener(object):
    def __init__(self):
        self.found = {}
    def removeService(self, server, type, name):
        if repr(name) in self.found:
            del self.found[repr(name)]
    def addService(self, server, type, name):
        self.found[repr(name)] = server.getServiceInfo(type, name)

def getzcpaths():
    ip = getip()
    if ip.startswith('127.'):
        return
    server = Zeroconf.Zeroconf(ip)
    l = listener()
    Zeroconf.ServiceBrowser(server, "_hg._tcp.local.", l)
    time.sleep(1)
    server.close()
    for value in l.found.values():
        name = value.name[:value.name.index('.')]
        url = "http://%s:%s%s" % (socket.inet_ntoa(value.address), value.port,
                                  value.properties.get("path", "/"))
        yield "zc-" + name, url

def config(orig, self, section, key, *args, **kwargs):
    if section == "paths" and key.startswith("zc-"):
        for name, path in getzcpaths():
            if name == key:
                return path
    return orig(self, section, key, *args, **kwargs)

def configitems(orig, self, section, *args, **kwargs):
    repos = orig(self, section, *args, **kwargs)
    if section == "paths":
        repos += getzcpaths()
    return repos

def configsuboptions(orig, self, section, name, *args, **kwargs):
    opt, sub = orig(self, section, name, *args, **kwargs)
    if section == "paths" and name.startswith("zc-"):
        # We have to find the URL in the zeroconf paths.  We can't cons up any
        # suboptions, so we use any that we found in the original config.
        for zcname, zcurl in getzcpaths():
            if zcname == name:
                return zcurl, sub
    return opt, sub

def defaultdest(orig, source):
    for name, path in getzcpaths():
        if path == source:
            return name.encode(encoding.encoding)
    return orig(source)

def cleanupafterdispatch(orig, ui, options, cmd, cmdfunc):
    try:
        return orig(ui, options, cmd, cmdfunc)
    finally:
        # we need to call close() on the server to notify() the various
        # threading Conditions and allow the background threads to exit
        global server
        if server:
            server.close()

extensions.wrapfunction(dispatch, '_runcommand', cleanupafterdispatch)

extensions.wrapfunction(uimod.ui, 'config', config)
extensions.wrapfunction(uimod.ui, 'configitems', configitems)
extensions.wrapfunction(uimod.ui, 'configsuboptions', configsuboptions)
extensions.wrapfunction(hg, 'defaultdest', defaultdest)
extensions.wrapfunction(servermod, 'create_server', zc_create_server)