def get_next_edge_offset(self):
"""Returns the offset into the database file where the
*next* edge with the same source node can be found.
IMPORTANT: You should always read the offset using this getter
rather than using the objects __dict__ or going around the name
mangling. The value is updated on each read in case the node's
underlying data has been changed since object instantiation.
Parameters
----------
None
Returns
-------
Integer"""
st = structs.unpack_edge(self.__graph._edge_map.read(self.id))
self.__next_edge = st[6]
return self.__next_edge
def get_next_edge_offset(self):
"""Returns the offset into the database file where the
*next* edge with the same source node can be found.
IMPORTANT: You should always read the offset using this getter
rather than using the objects __dict__ or going around the name
mangling. The value is updated on each read in case the node's
underlying data has been changed since object instantiation.
Parameters
----------
None
Returns
-------
Integer"""
st = structs.unpack_edge(self.__graph._edge_map.read(self.id))
self.__next_edge = st[6]
return self.__next_edge
def _from_struct(self, graphref, id_num, bin_str):
"""Reconstructs an Edge object from a struct of binary data.
IMPORTANT: Edge deletion in vgraph is lazy. When a node is
deleted, incoming edges are only deleted when a caller attempts
to access them. This method has the potential to return an edge
other than the one requested if the requested edge is discovered
to be "dangling" during object creation.
Parameters
----------
graphref: a reference to a vgraph Graph object
id_num: the integer ID for this Edge
bin_str: a string of binary data
Returns
-------
A vgraph Edge object"""
edge_tuple = structs.unpack_edge(bin_str)
node_1 = graphref.node(edge_tuple[1])
node_2 = graphref.node(edge_tuple[2])
e = Edge(
graphref,
node_1,
node_2,
label=re.sub(r'\x00', '', edge_tuple[3]),
direction=edge_tuple[4],
cost = edge_tuple[0]
)
e.id = id_num
e._set_previous_edge_offset(edge_tuple[5])
e._set_next_edge_offset(edge_tuple[6])
if node_2 is None:
graphref.delete_edge(e)
if edge_tuple[6] == edge_tuple[5]:
return []
return graphref.edge(edge_tuple[6])
return e
def _from_struct(self, graphref, id_num, bin_str):
"""Reconstructs an Edge object from a struct of binary data.
IMPORTANT: Edge deletion in vgraph is lazy. When a node is
deleted, incoming edges are only deleted when a caller attempts
to access them. This method has the potential to return an edge
other than the one requested if the requested edge is discovered
to be "dangling" during object creation.
Parameters
----------
graphref: a reference to a vgraph Graph object
id_num: the integer ID for this Edge
bin_str: a string of binary data
Returns
-------
A vgraph Edge object"""
edge_tuple = structs.unpack_edge(bin_str)
node_1 = graphref.node(edge_tuple[1])
node_2 = graphref.node(edge_tuple[2])
e = Edge(graphref,
node_1,
node_2,
label=re.sub(r'\x00', '', edge_tuple[3]),
direction=edge_tuple[4],
cost=edge_tuple[0])
e.id = id_num
e._set_previous_edge_offset(edge_tuple[5])
e._set_next_edge_offset(edge_tuple[6])
if node_2 is None:
graphref.delete_edge(e)
if edge_tuple[6] == edge_tuple[5]:
return []
return graphref.edge(edge_tuple[6])
return e
