view mercurial/hgweb/__init__.py @ 29375:fcaf20175b1b

demandimport: delay loading for "from a import b" with absolute_import

Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.

For example:

  - it is assumed that extension X has "from P import M" for module M
    under package P with absolute_import feature

  - if importing module M is already delayed before loading extension
    X, loading module M in extension X is delayed until actually
    referring

    util, cmdutil, scmutil or so of Mercurial itself should be
    imported by "from . import M" style before loading extension X

  - otherwise, module M is loaded immediately at loading extension X,
    even if extension X itself isn't used at that "hg" command invocation

    Some minor modules (e.g. filemerge or so) of Mercurial itself
    aren't imported by "from . import M" style before loading
    extension X. And of course, external libraries aren't, too.

This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.

To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:

  1. import root module of "name" by system built-in __import__
     (referred as _origimport)

  2. recurse down the module chain for hierarchical "name"

     This logic can be shared with non absolute_import
     case. Therefore, this patch also centralizes it into chainmodules().

  3. and fall through to process elements in "fromlist" for the leaf
     module of "name"

     Processing elements in "fromlist" is executed in the code path
     after "if _pypy: .... else: ..." clause. Therefore, this patch
     replaces "if _pypy:" with "elif _pypy:" to share it.

At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.

IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.

This is reason why this patch removes "errors for unknown reasons"
comment.

# hgweb/__init__.py - web interface to a mercurial repository
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005 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 os

from ..i18n import _

from .. import (
    error,
    util,
)

from . import (
    hgweb_mod,
    hgwebdir_mod,
    server,
)

def hgweb(config, name=None, baseui=None):
    '''create an hgweb wsgi object

    config can be one of:
    - repo object (single repo view)
    - path to repo (single repo view)
    - path to config file (multi-repo view)
    - dict of virtual:real pairs (multi-repo view)
    - list of virtual:real tuples (multi-repo view)
    '''

    if ((isinstance(config, str) and not os.path.isdir(config)) or
        isinstance(config, dict) or isinstance(config, list)):
        # create a multi-dir interface
        return hgwebdir_mod.hgwebdir(config, baseui=baseui)
    return hgweb_mod.hgweb(config, name=name, baseui=baseui)

def hgwebdir(config, baseui=None):
    return hgwebdir_mod.hgwebdir(config, baseui=baseui)

class httpservice(object):
    def __init__(self, ui, app, opts):
        self.ui = ui
        self.app = app
        self.opts = opts

    def init(self):
        util.setsignalhandler()
        self.httpd = server.create_server(self.ui, self.app)

        if self.opts['port'] and not self.ui.verbose:
            return

        if self.httpd.prefix:
            prefix = self.httpd.prefix.strip('/') + '/'
        else:
            prefix = ''

        port = ':%d' % self.httpd.port
        if port == ':80':
            port = ''

        bindaddr = self.httpd.addr
        if bindaddr == '0.0.0.0':
            bindaddr = '*'
        elif ':' in bindaddr: # IPv6
            bindaddr = '[%s]' % bindaddr

        fqaddr = self.httpd.fqaddr
        if ':' in fqaddr:
            fqaddr = '[%s]' % fqaddr
        if self.opts['port']:
            write = self.ui.status
        else:
            write = self.ui.write
        write(_('listening at http://%s%s/%s (bound to %s:%d)\n') %
              (fqaddr, port, prefix, bindaddr, self.httpd.port))
        self.ui.flush()  # avoid buffering of status message

    def run(self):
        self.httpd.serve_forever()

def createservice(ui, repo, opts):
    # this way we can check if something was given in the command-line
    if opts.get('port'):
        opts['port'] = util.getport(opts.get('port'))

    alluis = set([ui])
    if repo:
        baseui = repo.baseui
        alluis.update([repo.baseui, repo.ui])
    else:
        baseui = ui
    webconf = opts.get('web_conf') or opts.get('webdir_conf')
    if webconf:
        # load server settings (e.g. web.port) to "copied" ui, which allows
        # hgwebdir to reload webconf cleanly
        servui = ui.copy()
        servui.readconfig(webconf, sections=['web'])
        alluis.add(servui)
    else:
        servui = ui

    optlist = ("name templates style address port prefix ipv6"
               " accesslog errorlog certificate encoding")
    for o in optlist.split():
        val = opts.get(o, '')
        if val in (None, ''): # should check against default options instead
            continue
        for u in alluis:
            u.setconfig("web", o, val, 'serve')

    if webconf:
        app = hgwebdir_mod.hgwebdir(webconf, baseui=baseui)
    else:
        if not repo:
            raise error.RepoError(_("there is no Mercurial repository"
                                    " here (.hg not found)"))
        app = hgweb_mod.hgweb(repo, baseui=baseui)
    return httpservice(servui, app, opts)