1 files changed, 93 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/graph/DotOutputVisitor.java b/src/main/java/com/google/devtools/build/lib/graph/DotOutputVisitor.java
new file mode 100644
index 0000000000..2d18ac2d2e
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/graph/DotOutputVisitor.java
@@ -0,0 +1,93 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// All Rights Reserved.
+
+package com.google.devtools.build.lib.graph;
+
+import java.io.PrintWriter;
+
+/**
+ *  <p> An implementation of GraphVisitor for displaying graphs in dot
+ *  format. </p>
+ */
+public class DotOutputVisitor<T> implements GraphVisitor<T> {
+
+  /**
+   *  Constructs a dot output visitor.
+   *
+   *  The visitor writes to writer 'out', and rendering node labels as
+   *  strings using the specified displayer, 'disp'.
+   */
+  public DotOutputVisitor(PrintWriter out, LabelSerializer<T> disp) {
+    // assert disp != null;
+    // assert out != null;
+    this.out = out;
+    this.disp = disp;
+  }
+
+  private final LabelSerializer<T> disp;
+  protected final PrintWriter out;
+  private boolean closeAtEnd = false;
+
+  @Override
+  public void beginVisit() {
+    out.println("digraph mygraph {");
+  }
+
+  @Override
+  public void endVisit() {
+    out.println("}");
+    out.flush();
+    if (closeAtEnd) {
+      out.close();
+    }
+  }
+
+  @Override
+  public void visitEdge(Node<T> lhs, Node<T> rhs) {
+    String s_lhs = disp.serialize(lhs);
+    String s_rhs = disp.serialize(rhs);
+    out.println("\"" + s_lhs + "\" -> \"" + s_rhs + "\"");
+  }
+
+  @Override
+  public void visitNode(Node<T> node) {
+    out.println("\"" + disp.serialize(node) + "\"");
+  }
+
+  /******************************************************************
+   *                                                                *
+   *                           Factories                            *
+   *                                                                *
+   ******************************************************************/
+
+  /**
+   *  Create a DotOutputVisitor for output to a writer; uses default
+   *  LabelSerializer.
+   */
+  public static <U> DotOutputVisitor<U> create(PrintWriter writer) {
+    return new DotOutputVisitor<U>(writer, new DefaultLabelSerializer<U>());
+  }
+
+  /**
+   *  The default implementation of LabelSerializer simply serializes
+   *  each node using its toString method.
+   */
+  private static class DefaultLabelSerializer<T> implements LabelSerializer<T> {
+    @Override
+    public String serialize(Node<T> node) {
+      return node.getLabel().toString();
+    }
+  }
+}