Exemple #1
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  /**
   * Given a set of SCC nodes make this the lead member of the SCC and reroute all incoming and
   * outgoing links accordingly. This eager rewrite is based on the assumption that there are few
   * cycles so it is better to rewrite once and keep the graph easy to traverse.
   */
  public void makeLeadNodeFor(Set<GraphNode> members) {
    // Accumulate all successors
    Set<GraphNode> newSucc = new HashSet<>();
    Set<GraphNode> newSuccClosed = new HashSet<>();
    for (GraphNode n : members) {
      newSucc.addAll(n.succ);
      newSuccClosed.addAll(n.succClosed);
    }
    newSucc.removeAll(members);
    newSuccClosed.removeAll(members);
    succ = newSucc;
    succClosed = newSuccClosed;

    // Rewrite all direct successors to have us as predecessor
    for (GraphNode n : succ) {
      n.pred.removeAll(members);
      n.pred.add(this);
    }

    // Find all predecessor nodes and relink link them to point to us
    Set<GraphNode> done = new HashSet<>();
    Set<GraphNode> newAliases = new HashSet<>();
    for (GraphNode member : members) {
      addSiblings(newAliases, member);
    }
    becomeLeaderOf(newAliases);
    for (GraphNode n : members) {
      if (n != this) {
        pred.addAll(n.pred);
        n.relocateAllRefTo(this, done);
        n.becomeSubordinateOf(this);
      }
    }
    pred.removeAll(members);
  }
Exemple #2
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 /** Dump a set to a string for debug. */
 private static String dumpSet(Set<GraphNode> s) {
   StringBuffer sb = new StringBuffer();
   sb.append("{");
   boolean started = false;
   for (GraphNode value : s) {
     if (started) {
       sb.append(", ");
     } else {
       started = true;
     }
     sb.append(value.toString());
   }
   sb.append("}");
   return sb.toString();
 }
Exemple #3
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 /** Visit each predecessor of this node applying the given visitor. Breadth first. */
 private <Alpha, Beta> void doVisitPredecessors(
     Visitor<Alpha, Beta> visitor, Alpha arg1, Beta arg2, Set<GraphNode> seen) {
   if (seen.add(this)) {
     Collection<GraphNode> allKill = null;
     for (Iterator<GraphNode> i = pred.iterator(); i.hasNext(); ) {
       GraphNode pred = i.next();
       List<GraphNode> kill = visitor.visit(pred, this, arg1, arg2);
       if (kill != null) {
         if (allKill == null) allKill = new ArrayList<GraphNode>();
         allKill.addAll(kill);
       }
     }
     if (allKill != null) pred.removeAll(allKill);
     for (Iterator<GraphNode> i = pred.iterator(); i.hasNext(); ) {
       GraphNode pred = i.next();
       pred.doVisitPredecessors(visitor, arg1, arg2, seen);
     }
   }
 }
Exemple #4
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 @Override
 GraphNode leadNode(GraphNode unlessSpecified) {
   return leader.leadNode();
 }