def topological_iter()

in core/maxframe/core/graph/core.pyx [0:0]

• 32 lines of code
• 15 McCabe index (conditional complexity)

    def topological_iter(self, succ_checker=None, reverse=False):
        cdef:
            dict preds, succs
            set visited = set()
            list stack

        if len(self) == 0:
            return

        if reverse:
            preds, succs = self._successors, self._predecessors
        else:
            preds, succs = self._predecessors, self._successors

        # copy predecessors and successors
        succs = dict((k, set(v)) for k, v in succs.items())
        preds = dict((k, set(v)) for k, v in preds.items())

        def _default_succ_checker(_, predecessors):
            return len(predecessors) == 0

        succ_checker = succ_checker or _default_succ_checker

        stack = list((p for p, l in preds.items() if len(l) == 0))
        if not stack:
            raise GraphContainsCycleError
        while stack:
            node = stack.pop()
            yield node
            visited.add(node)
            for succ in succs.get(node, {}):
                if succ in visited:
                    raise GraphContainsCycleError
                succ_preds = preds[succ]
                succ_preds.remove(node)
                if succ_checker(succ, succ_preds):
                    stack.append(succ)
        if len(visited) != len(self):
            raise GraphContainsCycleError