~bzr-pqm/bzr/bzr.dev

2550.2.2 by Robert Collins
Add helpers to get api versions from objects.
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# Copyright (C) 2007 Canonical Ltd
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
4183.7.1 by Sabin Iacob
update FSF mailing address
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
2550.2.2 by Robert Collins
Add helpers to get api versions from objects.
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2550.2.3 by Robert Collins
Add require_api API.
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"""Library API versioning support.
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Added in bzrlib 0.18 this allows export of compatibility information about
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bzrlib. Please see doc/developers/api-versioning.txt for design details and
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examples.
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"""
2550.2.2 by Robert Collins
Add helpers to get api versions from objects.
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import bzrlib
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from bzrlib.lazy_import import lazy_import
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lazy_import(globals(), """
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from bzrlib.errors import IncompatibleAPI
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""")
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def get_current_api_version(object_with_api):
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    """Return the API version tuple for object_with_api.
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    :param object_with_api: An object to look for an API version on. If the
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        object has a api_current_version attribute, that is used. Otherwise if
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        there is a version_info attribute, its first three elements are used.
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        Finally if there was no version_info attribute, the current api version
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        of bzrlib itself is used.
2550.2.3 by Robert Collins
Add require_api API.
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    Added in bzrlib 0.18.
2550.2.2 by Robert Collins
Add helpers to get api versions from objects.
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    """
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    try:
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        return object_with_api.api_current_version
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    except AttributeError:
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        try:
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            return object_with_api.version_info[0:3]
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        except AttributeError:
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            return get_current_api_version(bzrlib)
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def get_minimum_api_version(object_with_api):
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    """Return the minimum API version supported by object_with_api.
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    :param object_with_api: An object to look for an API version on. If the
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        object has a api_minimum_version attribute, that is used. Otherwise the
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        minimum api version of bzrlib itself is used.
2550.2.3 by Robert Collins
Add require_api API.
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    Added in bzrlib 0.18.
2550.2.2 by Robert Collins
Add helpers to get api versions from objects.
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    """
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    try:
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        return object_with_api.api_minimum_version
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    except AttributeError:
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        return get_minimum_api_version(bzrlib)
2550.2.3 by Robert Collins
Add require_api API.
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def require_api(object_with_api, wanted_api):
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    """Check if object_with_api supports the api version wanted_api.
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    :param object_with_api: An object which exports an API minimum and current
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        version. See get_minimum_api_version and get_current_api_version for
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        details.
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    :param wanted_api: The API version for which support is required.
3766.3.3 by Robert Collins
Review tweaks.
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    :return: None
2550.2.3 by Robert Collins
Add require_api API.
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    :raises IncompatibleAPI: When the wanted_api is not supported by
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        object_with_api.
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    Added in bzrlib 0.18.
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    """
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    current = get_current_api_version(object_with_api)
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    minimum = get_minimum_api_version(object_with_api)
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    if wanted_api < minimum or wanted_api > current:
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        raise IncompatibleAPI(object_with_api, wanted_api, minimum, current)
3766.3.1 by Robert Collins
Add bzrlib.api.require_any_api, fixing bug 279447.
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3766.3.3 by Robert Collins
Review tweaks.
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3766.3.1 by Robert Collins
Add bzrlib.api.require_any_api, fixing bug 279447.
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def require_any_api(object_with_api, wanted_api_list):
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    """Check if object_with_api supports the api version wanted_api.
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    :param object_with_api: An object which exports an API minimum and current
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        version. See get_minimum_api_version and get_current_api_version for
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        details.
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    :param wanted_api: A list of API versions, any of which being available is
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        sufficent.
3766.3.3 by Robert Collins
Review tweaks.
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    :return: None
3766.3.1 by Robert Collins
Add bzrlib.api.require_any_api, fixing bug 279447.
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    :raises IncompatibleAPI: When the wanted_api is not supported by
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        object_with_api.
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    Added in bzrlib 1.9.
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    """
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    for api in wanted_api_list[:-1]:
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        try:
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            return require_api(object_with_api, api)
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        except IncompatibleAPI:
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            pass
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    require_api(object_with_api, wanted_api_list[-1])