Initial implementation of "Rename Local Variable" refactoring.

editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/changes/TextChangeCompatibility.java

Index: editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/changes/TextChangeCompatibility.java
diff --git a/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/changes/TextChangeCompatibility.java b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/changes/TextChangeCompatibility.java
new file mode 100644
index 0000000000000000000000000000000000000000..fab113b50995aecf0d2abbd19a8b6206c7d1c17d
--- /dev/null
+++ b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/changes/TextChangeCompatibility.java
@@ -0,0 +1,92 @@
+package com.google.dart.tools.internal.corext.refactoring.changes;
+
+import org.eclipse.core.runtime.Assert;
+import org.eclipse.ltk.core.refactoring.CategorizedTextEditGroup;
+import org.eclipse.ltk.core.refactoring.GroupCategorySet;
+import org.eclipse.ltk.core.refactoring.TextChange;
+import org.eclipse.ltk.core.refactoring.TextEditChangeGroup;
+import org.eclipse.text.edits.MalformedTreeException;
+import org.eclipse.text.edits.MultiTextEdit;
+import org.eclipse.text.edits.TextEdit;
+import org.eclipse.text.edits.TextEditGroup;
+
+/**
+ * A utility class to provide compatibility with the old text change API of adding text edits
+ * directly and auto inserting them into the tree.
+ */
+public class TextChangeCompatibility {
+
+  public static void addTextEdit(TextChange change, String name, TextEdit edit)
+      throws MalformedTreeException {
+    Assert.isNotNull(change);
+    Assert.isNotNull(name);
+    Assert.isNotNull(edit);
+    TextEdit root = change.getEdit();
+    if (root == null) {
+      root = new MultiTextEdit();
+      change.setEdit(root);
+    }
+    insert(root, edit);
+    change.addTextEditGroup(new TextEditGroup(name, edit));
+  }
+
+  public static void addTextEdit(TextChange change, String name, TextEdit edit,
+      GroupCategorySet groupCategories) throws MalformedTreeException {
+    Assert.isNotNull(change);
+    Assert.isNotNull(name);
+    Assert.isNotNull(edit);
+    TextEdit root = change.getEdit();
+    if (root == null) {
+      root = new MultiTextEdit();
+      change.setEdit(root);
+    }
+    insert(root, edit);
+    change.addTextEditChangeGroup(new TextEditChangeGroup(change, new CategorizedTextEditGroup(
+        name, edit, groupCategories)));
+  }
+
+  public static void insert(TextEdit parent, TextEdit edit) throws MalformedTreeException {
+    if (!parent.hasChildren()) {
+      parent.addChild(edit);
+      return;
+    }
+    TextEdit[] children = parent.getChildren();
+    // First dive down to find the right parent.
+    for (int i = 0; i < children.length; i++) {
+      TextEdit child = children[i];
+      if (covers(child, edit)) {
+        insert(child, edit);
+        return;
+      }
+    }
+    // We have the right parent. Now check if some of the children have to
+    // be moved under the new edit since it is covering it.
+    int removed = 0;
+    for (int i = 0; i < children.length; i++) {
+      TextEdit child = children[i];
+      if (covers(edit, child)) {
+        parent.removeChild(i - removed++);
+        edit.addChild(child);
+      }
+    }
+    parent.addChild(edit);
+  }
+
+  private static boolean covers(TextEdit thisEdit, TextEdit otherEdit) {
+    if (thisEdit.getLength() == 0) {
+      return false;
+    }
+
+    int thisOffset = thisEdit.getOffset();
+    int thisEnd = thisEdit.getExclusiveEnd();
+    if (otherEdit.getLength() == 0) {
+      int otherOffset = otherEdit.getOffset();
+      return thisOffset < otherOffset && otherOffset < thisEnd;
+    } else {
+      int otherOffset = otherEdit.getOffset();
+      int otherEnd = otherEdit.getExclusiveEnd();
+      return thisOffset <= otherOffset && otherEnd <= thisEnd;
+    }
+  }
+
+}