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Comrad/p2p/kademlia/node.py
2020-08-19 14:01:37 +01:00

128 lines
3.7 KiB
Python

from operator import itemgetter
import heapq
class Node:
"""
Simple object to encapsulate the concept of a Node (minimally an ID, but
also possibly an IP and port if this represents a node on the network).
This class should generally not be instantiated directly, as it is a low
level construct mostly used by the router.
"""
def __init__(self, node_id, ip=None, port=None):
"""
Create a Node instance.
Args:
node_id (int): A value between 0 and 2^160
ip (string): Optional IP address where this Node lives
port (int): Optional port for this Node (set when IP is set)
"""
self.id = node_id # pylint: disable=invalid-name
self.ip = ip # pylint: disable=invalid-name
self.port = port
self.long_id = int(node_id.hex(), 16)
def same_home_as(self, node):
return self.ip == node.ip and self.port == node.port
def distance_to(self, node):
"""
Get the distance between this node and another.
"""
return self.long_id ^ node.long_id
def __iter__(self):
"""
Enables use of Node as a tuple - i.e., tuple(node) works.
"""
return iter([self.id, self.ip, self.port])
def __repr__(self):
return repr([self.long_id, self.ip, self.port])
def __str__(self):
return "%s:%s" % (self.ip, str(self.port))
class NodeHeap:
"""
A heap of nodes ordered by distance to a given node.
"""
def __init__(self, node, maxsize):
"""
Constructor.
@param node: The node to measure all distnaces from.
@param maxsize: The maximum size that this heap can grow to.
"""
self.node = node
self.heap = []
self.contacted = set()
self.maxsize = maxsize
def remove(self, peers):
"""
Remove a list of peer ids from this heap. Note that while this
heap retains a constant visible size (based on the iterator), it's
actual size may be quite a bit larger than what's exposed. Therefore,
removal of nodes may not change the visible size as previously added
nodes suddenly become visible.
"""
peers = set(peers)
if not peers:
return
nheap = []
for distance, node in self.heap:
if node.id not in peers:
heapq.heappush(nheap, (distance, node))
self.heap = nheap
def get_node(self, node_id):
for _, node in self.heap:
if node.id == node_id:
return node
return None
def have_contacted_all(self):
return len(self.get_uncontacted()) == 0
def get_ids(self):
return [n.id for n in self]
def mark_contacted(self, node):
self.contacted.add(node.id)
def popleft(self):
return heapq.heappop(self.heap)[1] if self else None
def push(self, nodes):
"""
Push nodes onto heap.
@param nodes: This can be a single item or a C{list}.
"""
if not isinstance(nodes, list):
nodes = [nodes]
for node in nodes:
if node not in self:
distance = self.node.distance_to(node)
heapq.heappush(self.heap, (distance, node))
def __len__(self):
return min(len(self.heap), self.maxsize)
def __iter__(self):
nodes = heapq.nsmallest(self.maxsize, self.heap)
return iter(map(itemgetter(1), nodes))
def __contains__(self, node):
for _, other in self.heap:
if node.id == other.id:
return True
return False
def get_uncontacted(self):
return [n for n in self if n.id not in self.contacted]