private Vertex connectStrongly()

in java/io/bazel/rules/closure/Tarjan.java [122:164]

• 35 lines of code
• 9 McCabe index (conditional complexity)

    private Vertex<V> connectStrongly(V vertex) {
      // Set the depth index for v to the smallest unused index.
      Vertex<V> v = new Vertex<>(vertex, index++);
      vertices.put(vertex, v);
      stack.add(v);
      v.onStack = true;

      // Consider successors of v.
      for (V vertex2 : edges.get(v.vertex)) {
        Vertex<V> w = vertices.get(vertex2);
        if (w == null) {
          // Successor w has not yet been visited; recurse on it.
          w = connectStrongly(vertex2);
          v.lowlink = Math.min(v.lowlink, w.lowlink);
        } else if (w.onStack) {
          // Successor w is in stack and hence in the current SCC.
          v.lowlink = Math.min(v.lowlink, w.index);
        }
        if (w.equals(v)) {
          w.selfReferential = true;
        }
      }

      // If v is a root node, pop the stack and generate an SCC.
      if (v.lowlink == v.index) {
        if (!v.selfReferential && v.equals(stack.get(stack.size() - 1))) {
          sorted.add(stack.remove(stack.size() - 1).vertex);
          v.onStack = false;
        } else {
          ImmutableSet.Builder<V> scc = new ImmutableSet.Builder<>();
          Vertex<V> w;
          do {
            w = stack.remove(stack.size() - 1);
            w.onStack = false;
            sorted.add(w.vertex);
            scc.add(w.vertex);
          } while (!w.equals(v));
          result.add(scc.build());
        }
      }

      return v;
    }