annotate mercurial/demandimport.py @ 20172:181108726ea5

http: reuse authentication info after the first failed request (issue3567)

Context: mercurial access to repository server with http access, and this
server is protected by basic auth.

Before patch:

* mercurial try an anonymous access to server, server return 401 response and
  mercurial resend request with login / password information

After patch:

* mercurial try an anonymous access to server, server return 401
  response. For all subsequent requests, mercurial keep in memory this
  information (this server need basic auth information).

This patch reduce the number of http access against mercurial server.

Example, before patch :

10.10.168.170 - - [25/Oct/2013:15:44:51 +0200] "GET /hg/testagt?cmd=capabilities
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:44:52 +0200] "GET /hg/testagt?cmd=capabilities
HTTP/1.1" 200 147 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:00 +0200] "GET /hg/testagt?cmd=capabilities
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:01 +0200] "GET /hg/testagt?cmd=capabilities
HTTP/1.1" 200 147 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:03 +0200] "GET /hg/testagt?cmd=batch
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:04 +0200] "GET /hg/testagt?cmd=batch
HTTP/1.1" 200 42 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:06 +0200] "GET /hg/testagt?cmd=getbundle
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:07 +0200] "GET /hg/testagt?cmd=getbundle
HTTP/1.1" 200 61184 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:09 +0200] "GET /hg/testagt?cmd=listkeys
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:10 +0200] "GET /hg/testagt?cmd=listkeys
HTTP/1.1" 200 15 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:12 +0200] "GET /hg/testagt?cmd=listkeys
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [25/Oct/2013:15:45:12 +0200] "GET /hg/testagt?cmd=listkeys
HTTP/1.1" 200 - "-" "mercurial/proto-1.0"

Example after patch :

10.10.168.170 - - [28/Oct/2013:11:49:14 +0100] "GET /hg/testagt?cmd=capabilities
HTTP/1.1" 401 260 "-" "mercurial/proto-1.0"
10.10.168.170 - - [28/Oct/2013:11:49:15 +0100] "GET /hg/testagt?cmd=capabilities
HTTP/1.1" 200 147 "-" "mercurial/proto-1.0"
10.10.168.170 - - [28/Oct/2013:11:49:17 +0100] "GET /hg/testagt?cmd=batch
HTTP/1.1" 200 42 "-" "mercurial/proto-1.0"
10.10.168.170 - - [28/Oct/2013:11:49:19 +0100] "GET /hg/testagt?cmd=getbundle
HTTP/1.1" 200 61184 "-" "mercurial/proto-1.0"
10.10.168.170 - - [28/Oct/2013:11:49:22 +0100] "GET /hg/testagt?cmd=listkeys
HTTP/1.1" 200 15 "-" "mercurial/proto-1.0"
10.10.168.170 - - [28/Oct/2013:11:49:24 +0100] "GET /hg/testagt?cmd=listkeys
HTTP/1.1" 200 - "-" "mercurial/proto-1.0"

In this last example, you can see only one 401 response.

# demandimport.py - global demand-loading of modules for Mercurial
#
# Copyright 2006, 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.

'''
demandimport - automatic demandloading of modules

To enable this module, do:

  import demandimport; demandimport.enable()

Imports of the following forms will be demand-loaded:

  import a, b.c
  import a.b as c
  from a import b,c # a will be loaded immediately

These imports will not be delayed:

  from a import *
  b = __import__(a)
'''

import __builtin__
_origimport = __import__

nothing = object()

try:
    _origimport(__builtin__.__name__, {}, {}, None, -1)
except TypeError: # no level argument
    def _import(name, globals, locals, fromlist, level):
        "call _origimport with no level argument"
        return _origimport(name, globals, locals, fromlist)
else:
    _import = _origimport

def _hgextimport(importfunc, name, globals, *args):
    try:
        return importfunc(name, globals, *args)
    except ImportError:
        if not globals:
            raise
        # extensions are loaded with "hgext_" prefix
        hgextname = 'hgext_%s' % name
        nameroot = hgextname.split('.', 1)[0]
        contextroot = globals.get('__name__', '').split('.', 1)[0]
        if nameroot != contextroot:
            raise
        # retry to import with "hgext_" prefix
        return importfunc(hgextname, globals, *args)

class _demandmod(object):
    """module demand-loader and proxy"""
    def __init__(self, name, globals, locals, level=-1):
        if '.' in name:
            head, rest = name.split('.', 1)
            after = [rest]
        else:
            head = name
            after = []
        object.__setattr__(self, "_data",
                           (head, globals, locals, after, level))
        object.__setattr__(self, "_module", None)
    def _extend(self, name):
        """add to the list of submodules to load"""
        self._data[3].append(name)
    def _load(self):
        if not self._module:
            head, globals, locals, after, level = self._data
            mod = _hgextimport(_import, head, globals, locals, None, level)
            # load submodules
            def subload(mod, p):
                h, t = p, None
                if '.' in p:
                    h, t = p.split('.', 1)
                if getattr(mod, h, nothing) is nothing:
                    setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__))
                elif t:
                    subload(getattr(mod, h), t)

            for x in after:
                subload(mod, x)

            # are we in the locals dictionary still?
            if locals and locals.get(head) == self:
                locals[head] = mod
            object.__setattr__(self, "_module", mod)

    def __repr__(self):
        if self._module:
            return "<proxied module '%s'>" % self._data[0]
        return "<unloaded module '%s'>" % self._data[0]
    def __call__(self, *args, **kwargs):
        raise TypeError("%s object is not callable" % repr(self))
    def __getattribute__(self, attr):
        if attr in ('_data', '_extend', '_load', '_module'):
            return object.__getattribute__(self, attr)
        self._load()
        return getattr(self._module, attr)
    def __setattr__(self, attr, val):
        self._load()
        setattr(self._module, attr, val)

def _demandimport(name, globals=None, locals=None, fromlist=None, level=-1):
    if not locals or name in ignore or fromlist == ('*',):
        # these cases we can't really delay
        return _hgextimport(_import, name, globals, locals, fromlist, level)
    elif not fromlist:
        # import a [as b]
        if '.' in name: # a.b
            base, rest = name.split('.', 1)
            # email.__init__ loading email.mime
            if globals and globals.get('__name__', None) == base:
                return _import(name, globals, locals, fromlist, level)
            # if a is already demand-loaded, add b to its submodule list
            if base in locals:
                if isinstance(locals[base], _demandmod):
                    locals[base]._extend(rest)
                return locals[base]
        return _demandmod(name, globals, locals, level)
    else:
        if level != -1:
            # from . import b,c,d or from .a import b,c,d
            return _origimport(name, globals, locals, fromlist, level)
        # from a import b,c,d
        mod = _hgextimport(_origimport, name, globals, locals)
        # recurse down the module chain
        for comp in name.split('.')[1:]:
            if getattr(mod, comp, nothing) is nothing:
                setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__))
            mod = getattr(mod, comp)
        for x in fromlist:
            # set requested submodules for demand load
            if getattr(mod, x, nothing) is nothing:
                setattr(mod, x, _demandmod(x, mod.__dict__, locals))
        return mod

ignore = [
    '_hashlib',
    '_xmlplus',
    'fcntl',
    'win32com.gen_py',
    '_winreg', # 2.7 mimetypes needs immediate ImportError
    'pythoncom',
    # imported by tarfile, not available under Windows
    'pwd',
    'grp',
    # imported by profile, itself imported by hotshot.stats,
    # not available under Windows
    'resource',
    # this trips up many extension authors
    'gtk',
    # setuptools' pkg_resources.py expects "from __main__ import x" to
    # raise ImportError if x not defined
    '__main__',
    '_ssl', # conditional imports in the stdlib, issue1964
    'rfc822',
    'mimetools',
    ]

def enable():
    "enable global demand-loading of modules"
    __builtin__.__import__ = _demandimport

def disable():
    "disable global demand-loading of modules"
    __builtin__.__import__ = _origimport