Added support for dumping AST to console, text file or dot file

compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java

Index: compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java
===================================================================
--- compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java	(revision 0)
+++ compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java	(revision 0)
@@ -0,0 +1,108 @@
+// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.google.dart.compiler.ast.viz;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import com.google.common.io.Closeables;
+import com.google.dart.compiler.ast.DartExpression;
+import com.google.dart.compiler.ast.DartNode;
+import com.google.dart.compiler.ast.DartUnit;
+
+/**
+ * Write the AST in Dot format. Output file is placed next to the JS file in the output directory
+ */
+public class DotWriter extends BaseASTWriter {
+
+  private Map<DartNode, String> nodeMap;
+  private FileWriter out;
+  private StringBuffer edges, nodes;
+  private DartUnit currentUnit;
+  private Set<String> printDataNodes;
+  private static final String[] dataLabels = {
+      "DartIdentifier", "DartVariable", "DartField", "DartParameter", "DartClass",
+      "DartMethodDefinition"};
+
+  public DotWriter(String outputDir) {
+    super(outputDir);
+    printDataNodes = new HashSet<String>(Arrays.asList(dataLabels));
+  }
+
+  @Override
+  protected void startHook(DartUnit unit) {
+    String nodeData = String.format("%s", unit.getSourceName());
+    nodeMap = new HashMap<DartNode, String>();
+    nodeMap.put(unit, nodeData);
+    edges = new StringBuffer();
+    nodes = new StringBuffer();
+    currentUnit = unit;
+    if (!isIgnored(unit)) {
+      String dotFilePath = outputDir + File.separator + unit.getSource().getUri() + ".ast.dot";
+      makeParentDirs(dotFilePath);
+      try {
+        out = new FileWriter(new File(dotFilePath));
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+    }
+
+  }
+
+  @Override
+  protected void endHook(DartUnit unit) {
+    if (!isIgnored(unit)) {
+      String dotGraph = "digraph G{\n" + nodes.toString() + edges.toString() + "}";
+      try {
+        out.append(dotGraph);
+        Closeables.close(out, true);
+      } catch (IOException e) {
+        System.err.println("Error while writing AST to dot file");
+        e.printStackTrace();
+      }
+    }
+  }
+
+  protected void write(String nodeType, DartNode node, String data) {
+    String nodeData = node.getSourceLine() + ":" + node.getSourceStart() + ":"
+        + node.getSourceLength() + "_" + nodeType;
+    nodeMap.put(node, nodeData);
+    DartNode parent = node.getParent();
+    if (parent == null) {
+      parent = currentUnit;
+    }
+    String styleAttr = getStyleAttr(nodeType, node);
+    String label = getLabel(nodeType, node, data);
+    nodes.append(String.format("\t\"%s\" [label=\"%s\"%s];\n", nodeData, label, styleAttr));
+    edges.append(String.format("\t\"%s\" -> \"%s\";\n", nodeMap.get(parent), nodeData));
+  }
+
+  private String getLabel(String nodeType, DartNode node, String data) {
+    StringBuffer label = new StringBuffer(nodeType);
+    if (printDataNodes.contains(nodeType) || node instanceof DartExpression) {
+      label.append(String.format("\\n%s", data.replaceAll("\"", "'")));
+    }
+    return label.toString();
+  }
+
+  private String getStyleAttr(String nodeType, DartNode node) {
+    StringBuffer style = new StringBuffer();
+    if (nodeType.endsWith("Literal") || "DartIdentifier".equals(nodeType)) {
+      style.append(", shape=box"); // OR style=filled, color=yellow
+    } else if ("DartClass".equals(nodeType)) {
+      style.append(", shape=doubleoctagon");
+    } else if ("DartMethodDefinition".equals(nodeType)) {
+      style.append(", color=blue");
+    }
+    return style.toString();
+  }
+
+}