1 #

     2 # Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>

     3 # All Rights Reserved.

     4 #

     5 # This software is subject to the provisions of the Zope Public License,

     6 # Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.

     7 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED

     8 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

     9 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS

    10 # FOR A PARTICULAR PURPOSE.

    11 #

    12 

    13 __docformat__ = 'restructuredtext'

    14 

    15 

    16 # import standard library

    17 

    18 # import interfaces

    19 from zope.container.interfaces import IContainer, IContained

    20 from zope.lifecycleevent.interfaces import IObjectMovedEvent

    21 from zope.location.interfaces import ISublocations

    22 

    23 # import packages

    24 from BTrees.OOBTree import OOBTree

    25 from persistent.list import PersistentList

    26 from pyams_utils.adapter import adapter_config, ContextAdapter

    27 from pyramid.threadlocal import get_current_registry

    28 from zope.container.ordered import OrderedContainer

    29 

    30 

    31 class BTreeOrderedContainer(OrderedContainer):

    32     """BTree based ordered container

    33 

    34     This container maintain a manual order of it's contents

    35     """

    36 

    37     def __init__(self):

    38         self._data = OOBTree()

    39         self._order = PersistentList()

    40 

    41 

    42 class ParentSelector(object):

    43     """Interface based parent selector

    44 

    45     This selector can be used as a subscriber predicate on IObjectAddedEvent to define

    46     an interface that the new parent must support for the event to be applied::

    47 

    48     .. code-block:: python

    49 

    50         from pyams_utils.interfaces.site import ISiteRoot

    51 

    52         @subscriber(IObjectAddedEvent, parent_selector=ISiteRoot)

    53         def siteroot_object_added_event_handler(event):

    54             '''This is an event handler for an ISiteRoot object added event'''

    55     """

    56 

    57     def __init__(self, ifaces, config):

    58         if not isinstance(ifaces, (list, tuple, set)):

    59             ifaces = (ifaces,)

    60         self.interfaces = ifaces

    61 

    62     def text(self):

    63         return 'parent_selector = %s' % str(self.interfaces)

    64 

    65     phash = text

    66 

    67     def __call__(self, event):

    68         if not IObjectMovedEvent.providedBy(event):

    69             return False

    70         for intf in self.interfaces:

    71             try:

    72                 if intf.providedBy(event.newParent):

    73                     return True

    74             except (AttributeError, TypeError):

    75                 if isinstance(event.newParent, intf):

    76                     return True

    77         return False

    78 

    79 

    80 @adapter_config(context=IContained, provides=ISublocations)

    81 class ContainerSublocationsAdapter(ContextAdapter):

    82     """Contained object sub-locations adapter

    83 

    84     This adapter checks for custom ISublocations interface adapters which can

    85     be defined by any component to get access to inner locations, defined for

    86     example via annotations.

    87     """

    88 

    89     def sublocations(self):

    90         """See `zope.location.interfaces.ISublocations` interface"""

    91         context = self.context

    92         # Check for adapted sub-locations first...

    93         registry = get_current_registry()

    94         for name, adapter in registry.getAdapters((context,), ISublocations):

    95             if not name:  # don't reuse default adapter!!

    96                 continue

    97             yield from adapter.sublocations()

    98         # then yield container items

    99         if IContainer.providedBy(context):

   100             yield from context.values()

   101 

   102 

   103 def find_objects_matching(root, condition, ignore_root=False):

   104     """Find all objects in root that match the condition

   105 

   106     The condition is a Python callable object that takes an object as

   107     argument and must return a boolean result.

   108 

   109     All sub-objects of the root will also be searched recursively.

   110 

   111     :param object root: the parent object from which search is started

   112     :param callable condition: a callable object which may return true for a given

   113         object to be selected

   114     :param boolean ignore_root: if *True*, the root object will not be returned, even if it matches

   115         the given condition

   116     :return: an iterator for all root's sub-objects matching condition

   117     """

   118     if (not ignore_root) and condition(root):

   119         yield root

   120     locations = ISublocations(root, None)

   121     if locations is not None:

   122         for location in locations.sublocations():

   123             if condition(location):

   124                 yield location

   125             yield from find_objects_matching(location, condition, ignore_root=True)

   126 

   127 

   128 def find_objects_providing(root, interface):

   129     """Find all objects in root that provide the specified interface

   130 

   131     All sub-objects of the root will also be searched recursively.

   132 

   133     :param object root: object; the parent object from which search is started

   134     :param Interface interface: interface; an interface that sub-objects should provide

   135     :return: an iterator for all root's sub-objects that provide the given interface

   136     """

   137     yield from find_objects_matching(root, interface.providedBy)