def _layout(self):
self._initialize()
# order the nodes
ordered_nodes = CFGUtils.quasi_topological_sort_nodes(self.graph)
# conver the graph to an acylic graph
acyclic_graph = self._to_acyclic_graph(self.graph, ordered_nodes=ordered_nodes)
# assign row and column to each node
self._assign_grid_locations(self.graph, acyclic_graph, ordered_nodes=ordered_nodes)
# edge routing
edge_router = EdgeRouter(self.graph, self._cols, self._rows, self._locations, self._max_col, self._max_row)
self.edges = edge_router.edges
self._vertical_edges = edge_router.vertical_edges
self._horizontal_edges = edge_router.horizontal_edges
# determine the maximum index for each grid
self._set_max_grid_edge_id()
# determine row and column sizes
self._make_grids()
# calculate coordinates of nodes
self._calculate_coordinates()
def _to_acyclic_graph(self, graph, ordered_nodes=None):
"""
Convert a given DiGraph into an acyclic graph.
:param networkx.DiGraph graph: The graph to convert.
:param list ordered_nodes: A list of nodes sorted in a topological order.
:return: The converted acyclic graph.
"""
if ordered_nodes is None:
# take the quasi-topological order of the graph
ordered_nodes = CFGUtils.quasi_topological_sort_nodes(graph)
acyclic_graph = networkx.DiGraph()
# add each node and its edge into the graph
visited = set()
for node in ordered_nodes:
visited.add(node)
acyclic_graph.add_node(node)
for successor in graph.successors(node):
if successor not in visited:
acyclic_graph.add_edge(node, successor)
return acyclic_graph
def sort_nodes(self, nodes=None):
sorted_nodes = CFGUtils.quasi_topological_sort_nodes(self.cfg.graph)
if nodes is not None:
sorted_nodes = [n for n in sorted_nodes if n in set(nodes)]
return sorted_nodes
def _assign_grid_locations(self, graph, acyclic_graph, ordered_nodes=None):
"""
Assign locations to each node in the graph in a bottom-up manner.
:param networkx.DiGraph graph: The original graph.
:param networkx.DiGraph acyclic_graph: The acyclic graph to work on.
:param list ordered_nodes: A list of nodes sorted in a topological order.
:return: None
"""
if ordered_nodes is None:
# take the quasi-topological order of the graph
ordered_nodes = CFGUtils.quasi_topological_sort_nodes(acyclic_graph)
self._assign_rows(graph, acyclic_graph, ordered_nodes)
self._assign_columns(acyclic_graph)