| commit | author | age | ||
| cbdc36 | 1 | ############################################################################## |
| CM | 2 | # |
| 3 | # Copyright (c) 2003 Zope Corporation and Contributors. | |
| 4 | # All Rights Reserved. | |
| 5 | # | |
| 6 | # This software is subject to the provisions of the Zope Public License, | |
| 7 | # Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution. | |
| 8 | # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED | |
| 9 | # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
| 10 | # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS | |
| 11 | # FOR A PARTICULAR PURPOSE. | |
| 12 | # | |
| 13 | ############################################################################## | |
| 14 | ||
| 3e2f12 | 15 | def inside(resource1, resource2): |
| CM | 16 | """Is ``resource1`` 'inside' ``resource2``? Return ``True`` if so, else |
| cbdc36 | 17 | ``False``. |
| CM | 18 | |
| 3e2f12 | 19 | ``resource1`` is 'inside' ``resource2`` if ``resource2`` is a |
| CM | 20 | :term:`lineage` ancestor of ``resource1``. It is a lineage ancestor |
| 8b1f6e | 21 | if its parent (or one of its parent's parents, etc.) is an |
| CM | 22 | ancestor. |
| cbdc36 | 23 | """ |
| 3e2f12 | 24 | while resource1 is not None: |
| CM | 25 | if resource1 is resource2: |
| cbdc36 | 26 | return True |
| 3e2f12 | 27 | resource1 = resource1.__parent__ |
| cbdc36 | 28 | |
| CM | 29 | return False |
| 30 | ||
| 3e2f12 | 31 | def lineage(resource): |
| cbdc36 | 32 | """ |
| 8b1f6e | 33 | Return a generator representing the :term:`lineage` of the |
| 3e2f12 | 34 | :term:`resource` object implied by the ``resource`` argument. The |
| CM | 35 | generator first returns ``resource`` unconditionally. Then, if |
| f4f41f | 36 | ``resource`` supplies a ``__parent__`` attribute, return the resource |
| CM | 37 | represented by ``resource.__parent__``. If *that* resource has a |
| 38 | ``__parent__`` attribute, return that resource's parent, and so on, | |
| 39 | until the resource being inspected either has no ``__parent__`` | |
| 8b1f6e | 40 | attribute or which has a ``__parent__`` attribute of ``None``. |
| f4f41f | 41 | For example, if the resource tree is:: |
| cbdc36 | 42 | |
| CM | 43 | thing1 = Thing() |
| 44 | thing2 = Thing() | |
| 45 | thing2.__parent__ = thing1 | |
| 46 | ||
| 47 | Calling ``lineage(thing2)`` will return a generator. When we turn | |
| 48 | it into a list, we will get:: | |
| 49 | ||
| 50 | list(lineage(thing2)) | |
| 51 | [ <Thing object at thing2>, <Thing object at thing1> ] | |
| 52 | """ | |
| 3e2f12 | 53 | while resource is not None: |
| CM | 54 | yield resource |
| 02e1fe | 55 | # The common case is that the AttributeError exception below |
| CM | 56 | # is exceptional as long as the developer is a "good citizen" |
| 57 | # who has a root object with a __parent__ of None. Using an | |
| 58 | # exception here instead of a getattr with a default is an | |
| 59 | # important micro-optimization, because this function is | |
| 60 | # called in any non-trivial application over and over again to | |
| 61 | # generate URLs and paths. | |
| 62 | try: | |
| 3e2f12 | 63 | resource = resource.__parent__ |
| 02e1fe | 64 | except AttributeError: |
| 3e2f12 | 65 | resource = None |
| cbdc36 | 66 | |
