jdk8-mips64-public/langtools: src/share/classes/com/sun/tools/javac/util/GraphUtils.java@93012e2a5d1d (annotated)

src/share/classes/com/sun/tools/javac/util/GraphUtils.java@93012e2a5d1d (annotated)

src/share/classes/com/sun/tools/javac/util/GraphUtils.java

Sat, 07 Nov 2020 10:30:02 +0800

author: aoqi
date: Sat, 07 Nov 2020 10:30:02 +0800
changeset 3938: 93012e2a5d1d
parent 3295: 859dc787b52b
permissions: -rw-r--r--

Added tag mips-jdk8u275-b01 for changeset eb6ee6a5f2fe

 /*
  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package com.sun.tools.javac.util;
 /** <p><b>This is NOT part of any supported API.
  *  If you write code that depends on this, you do so at your own risk.
  *  This code and its internal interfaces are subject to change or
  *  deletion without notice.</b>
  */
 public class GraphUtils {
     /**
      * Basic interface for defining various dependency kinds. All dependency kinds
      * must at least support basic capabilities to tell the DOT engine how to render them.
      */
     public interface DependencyKind {
         /**
          * Returns the DOT representation (to be used in a {@code style} attribute
          * that's most suited for this dependency kind.
          */
         String getDotStyle();
     }
     /**
      * This class is a basic abstract class for representing a node.
      * A node is associated with a given data.
      */
     public static abstract class Node<D> {
         public final D data;
         public Node(D data) {
             this.data = data;
         }
         /**
          * Get an array of the dependency kinds supported by this node.
          */
         public abstract DependencyKind[] getSupportedDependencyKinds();
         /**
          * Get all dependencies, regardless of their kind.
          */
         public abstract Iterable<? extends Node<D>> getAllDependencies();
         /**
          * Get a name for the dependency (of given kind) linking this node to a given node
          */
         public abstract String getDependencyName(Node<D> to, DependencyKind dk);
         @Override
         public String toString() {
             return data.toString();
         }
     }
     /**
      * This class specialized Node, by adding elements that are required in order
      * to perform Tarjan computation of strongly connected components.
      */
     public static abstract class TarjanNode<D> extends Node<D> implements Comparable<TarjanNode<D>> {
         int index = -1;
         int lowlink;
         boolean active;
         public TarjanNode(D data) {
             super(data);
         }
         public abstract Iterable<? extends TarjanNode<D>> getAllDependencies();
         public abstract Iterable<? extends TarjanNode<D>> getDependenciesByKind(DependencyKind dk);
         public int compareTo(TarjanNode<D> o) {
             return (index < o.index) ? -1 : (index == o.index) ? 0 : 1;
         }
     }
     /**
      * Tarjan's algorithm to determine strongly connected components of a
      * directed graph in linear time. Works on TarjanNode.
      */
     public static <D, N extends TarjanNode<D>> List<? extends List<? extends N>> tarjan(Iterable<? extends N> nodes) {
         Tarjan<D, N> tarjan = new Tarjan<>();
         return tarjan.findSCC(nodes);
     }
     //where
     private static class Tarjan<D, N extends TarjanNode<D>> {
         /** Unique node identifier. */
         int index = 0;
         /** List of SCCs found so far. */
         ListBuffer<List<N>> sccs = new ListBuffer<>();
         /** Stack of all reacheable nodes from given root. */
         ListBuffer<N> stack = new ListBuffer<>();
         private List<? extends List<? extends N>> findSCC(Iterable<? extends N> nodes) {
             for (N node : nodes) {
                 if (node.index == -1) {
                     findSCC(node);
                 }
             }
             return sccs.toList();
         }
         private void findSCC(N v) {
             visitNode(v);
             for (TarjanNode<D> tn : v.getAllDependencies()) {
                 @SuppressWarnings("unchecked")
                 N n = (N)tn;
                 if (n.index == -1) {
                     //it's the first time we see this node
                     findSCC(n);
                     v.lowlink = Math.min(v.lowlink, n.lowlink);
                 } else if (stack.contains(n)) {
                     //this node is already reachable from current root
                     v.lowlink = Math.min(v.lowlink, n.index);
                 }
             }
             if (v.lowlink == v.index) {
                 //v is the root of a SCC
                 addSCC(v);
             }
         }
         private void visitNode(N n) {
             n.index = index;
             n.lowlink = index;
             index++;
             stack.prepend(n);
             n.active = true;
         }
         private void addSCC(N v) {
             N n;
             ListBuffer<N> cycle = new ListBuffer<>();
             do {
                 n = stack.remove();
                 n.active = false;
                 cycle.add(n);
             } while (n != v);
             sccs.add(cycle.toList());
         }
     }
     /**
      * Debugging: dot representation of a set of connected nodes. The resulting
      * dot representation will use {@code Node.toString} to display node labels
      * and {@code Node.printDependency} to display edge labels. The resulting
      * representation is also customizable with a graph name and a header.
      */
     public static <D> String toDot(Iterable<? extends TarjanNode<D>> nodes, String name, String header) {
         StringBuilder buf = new StringBuilder();
         buf.append(String.format("digraph %s {\n", name));
         buf.append(String.format("label = \"%s\";\n", header));
         //dump nodes
         for (TarjanNode<D> n : nodes) {
             buf.append(String.format("%s [label = \"%s\"];\n", n.hashCode(), n.toString()));
         }
         //dump arcs
         for (TarjanNode<D> from : nodes) {
             for (DependencyKind dk : from.getSupportedDependencyKinds()) {
                 for (TarjanNode<D> to : from.getDependenciesByKind(dk)) {
                     buf.append(String.format("%s -> %s [label = \" %s \" style = %s ];\n",
                             from.hashCode(), to.hashCode(), from.getDependencyName(to, dk), dk.getDotStyle()));
                 }
             }
         }
         buf.append("}\n");
         return buf.toString();
     }
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/com/sun/tools/javac/util/GraphUtils.java@93012e2a5d1d (annotated)

src/share/classes/com/sun/tools/javac/util/GraphUtils.java