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#!/usr/bin/env python
#
# This library is free software, distributed under the terms of
# the GNU Lesser General Public License Version 3, or any later version.
# See the COPYING file included in this archive
#
# The docstrings in this module contain epytext markup; API documentation
# may be created by processing this file with epydoc: http://epydoc.sf.net
import constants
class BucketFull(Exception):
""" Raised when the bucket is full """
class KBucket(object):
""" Description - later
"""
def __init__(self, rangeMin, rangeMax):
"""
@param rangeMin: The lower boundary for the range in the 160-bit ID
space covered by this k-bucket
@param rangeMax: The upper boundary for the range in the ID space
covered by this k-bucket
"""
self.lastAccessed = 0
self.rangeMin = rangeMin
self.rangeMax = rangeMax
self._contacts = list()
def addContact(self, contact):
""" Add contact to _contact list in the right order. This will move the
contact to the end of the k-bucket if it is already present.
@raise kademlia.kbucket.BucketFull: Raised when the bucket is full and
the contact isn't in the bucket
already
@param contact: The contact to add
@type contact: kademlia.contact.Contact
"""
if contact in self._contacts:
# Move the existing contact to the end of the list
# - using the new contact to allow add-on data (e.g. optimization-specific stuff) to pe updated as well
self._contacts.remove(contact)
self._contacts.append(contact)
elif len(self._contacts) < constants.k:
self._contacts.append(contact)
else:
raise BucketFull("No space in bucket to insert contact")
def getContact(self, contactID):
""" Get the contact specified node ID"""
index = self._contacts.index(contactID)
return self._contacts[index]
def getContacts(self, count=-1, excludeContact=None):
""" Returns a list containing up to the first count number of contacts
@param count: The amount of contacts to return (if 0 or less, return
all contacts)
@type count: int
@param excludeContact: A contact to exclude; if this contact is in
the list of returned values, it will be
discarded before returning. If a C{str} is
passed as this argument, it must be the
contact's ID.
@type excludeContact: kademlia.contact.Contact or str
@raise IndexError: If the number of requested contacts is too large
@return: Return up to the first count number of contacts in a list
If no contacts are present an empty is returned
@rtype: list
"""
# Return all contacts in bucket
if count <= 0:
count = len(self._contacts)
# Get current contact number
currentLen = len(self._contacts)
# If count greater than k - return only k contacts
if count > constants.k:
count = constants.k
# Check if count value in range and,
# if count number of contacts are available
if not currentLen:
contactList = list()
# length of list less than requested amount
elif currentLen < count:
contactList = self._contacts[0:currentLen]
# enough contacts in list
else:
contactList = self._contacts[0:count]
if excludeContact in contactList:
contactList.remove(excludeContact)
return contactList
def removeContact(self, contact):
""" Remove given contact from list
@param contact: The contact to remove, or a string containing the
contact's node ID
@type contact: kademlia.contact.Contact or str
@raise ValueError: The specified contact is not in this bucket
"""
self._contacts.remove(contact)
def keyInRange(self, key):
""" Tests whether the specified key (i.e. node ID) is in the range
of the 160-bit ID space covered by this k-bucket (in otherwords, it
returns whether or not the specified key should be placed in this
k-bucket)
@param key: The key to test
@type key: str or int
@return: C{True} if the key is in this k-bucket's range, or C{False}
if not.
@rtype: bool
"""
if isinstance(key, str):
key = long(key.encode('hex'), 16)
return self.rangeMin <= key < self.rangeMax
def __len__(self):
return len(self._contacts)
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