lang-impl/src/com/intellij/psi/impl/source/tree/RecursiveTreeElementWalkingVisitor.java

   1 package com.intellij.psi.impl.source.tree;
   2
   3 import com.intellij.psi.impl.source.parsing.ChameleonTransforming;
   4
   5 public abstract class RecursiveTreeElementWalkingVisitor extends TreeElementVisitor{
   6   private boolean startedWalking;
   7   private boolean isDown;
   8   private final boolean myDoTransform;
   9
  10   protected RecursiveTreeElementWalkingVisitor() {
  11     this(true);
  12   }
  13   protected RecursiveTreeElementWalkingVisitor(boolean doTransform) {
  14     myDoTransform = doTransform;
  15   }
  16
  17   @Override public void visitLeaf(LeafElement leaf) {
  18     visitNode(leaf);
  19   }
  20
  21   @Override public void visitComposite(CompositeElement composite) {
  22     if (myDoTransform) ChameleonTransforming.transformChildren(composite);
  23     isDown = visitNode(composite);
  24     if (!startedWalking) {
  25       startedWalking = true;
  26       walk(composite);
  27       startedWalking = false;
  28     }
  29   }
  30
  31   private void walk(TreeElement root) {
  32     for (TreeElement element = next(root, root); element != null; element = next(element, root)) {
  33       CompositeElement parent = element.getTreeParent();
  34       TreeElement next = element.getTreeNext();
  35       isDown = false; // if client visitor did not call default visitElement it means skip subtree
  36       element.acceptTree(this);
  37       assert element.getTreeNext() == next;
  38       assert element.getTreeParent() == parent;
  39     }
  40   }
  41
  42   private TreeElement next(TreeElement element, TreeElement root) {
  43     if (isDown) {
  44       TreeElement child = element.getFirstChildNode();
  45       if (child != null) return child;
  46     }
  47
  48     // up
  49     while (element != root) {
  50       TreeElement next = element.getTreeNext();
  51       if (next != null) {
  52         assert next.getTreePrev() == element;
  53         return next;
  54       }
  55       element = element.getTreeParent();
  56     }
  57     return null;
  58   }
  59
  60   protected boolean visitNode(TreeElement element){
  61     return true;
  62   }
  63 }