Java Code Examples for org.eclipse.xtext.parsetree.reconstr.impl.NodeIterator#prune()

/**
 * Helper method that collects all the hidden tokens that follow the given node.
 *
 * @param from
 *          starting point in the node model, must not be {@code null}
 * @param deletedSemanticElements
 *          set of semantic elements that have been deleted from the model, must not be {@code null}
 * @return list of hidden tokens, never {@code null}, can be empty
 */
private List<INode> getFollowingHiddenTokens(final INode from, final Set<EObject> deletedSemanticElements) {
  List<INode> result = Lists.newArrayList();
  NodeIterator nodes = new NodeIterator(from);
  while (nodes.hasNext()) {
    INode next = nodes.next();
    if (next.getTotalOffset() > rootEndOffset || next.equals(lastEmittedNode)) {
      break;
    } else if (tokenUtil.isWhitespaceOrCommentNode(next)) {
      if (!emittedComments.contains(next)) {
        result.add(next);
      }
    } else if (belongsToDeletedElement(next)) {
      handleDeletedElement(result, deletedSemanticElements, next);
      nodes.prune();
    } else {
      break;
    }
  }
  return result;
}
 

/**
 * Helper method that collects all the preceding hidden tokens for the given node.
 *
 * @param to
 *          node model element to get the tokens for, must not be {@code null}
 * @param deletedSemanticElements
 *          set of semantic elements that have been deleted from the model, must not be {@code null}
 * @return list of hidden tokens, never {@code null}, can be empty
 */
private List<INode> getPrecedingHiddenTokens(final INode to, final Set<EObject> deletedSemanticElements) {
  List<INode> result = Lists.newLinkedList();
  NodeIterator nodes = new NodeIterator(to);
  while (nodes.hasPrevious()) {
    INode previous = nodes.previous();
    if (previous.getTotalEndOffset() < rootOffset || previous.equals(lastEmittedNode)) {
      break;
    } else if (tokenUtil.isWhitespaceOrCommentNode(previous)) {
      if (!emittedComments.contains(previous)) {
        result.add(0, previous);
      }
    } else if (belongsToDeletedElement(previous)) {
      handleDeletedElement(result, deletedSemanticElements, previous);
      nodes.prune();
    } else {
      break;
    }
  }
  return result;
}
 

@Test public void testPruneComposite() throws Exception {
	NodeIterator nodeIterator = new NodeIterator(nodes[3]);
	nodeIterator.prune();
	assertEquals(nodes[6], nodeIterator.next());
	assertEquals(nodes[3], nodeIterator.previous());
	assertEquals(nodes[2], nodeIterator.previous());
	assertEquals(nodes[1], nodeIterator.previous());
}
 

@Test public void testPruneLeaf() throws Exception {
	// pruning a leaf should not have any effect
	NodeIterator nodeIterator = new NodeIterator(nodes[8]);
	nodeIterator.prune();
	assertEquals(nodes[9], nodeIterator.next());
	assertEquals(nodes[8], nodeIterator.previous());
	assertEquals(nodes[7], nodeIterator.previous());
	assertEquals(nodes[6], nodeIterator.previous());
}
 

/**
 * Collects all the hidden tokens between two given nodes of the node model.
 *
 * @param from
 *          node that serves as a start point, must not be {@code null}
 * @param to
 *          search end point, must not be {@code null}
 * @param deletedSemanticElements
 *          set of the deleted semantic elements, must not be {@code null}
 * @return list of hidden tokens, never {@code null}, but can be empty
 */
private List<INode> getHiddenTokensBetween(final INode from, final INode to, final Set<EObject> deletedSemanticElements) {
  EObject fromElement = NodeModelUtils.findActualSemanticObjectFor(from);
  if (from.equals(NodeModelUtils.getNode(fromElement))) {
    // If the starting node represents some container, emit the comments that belong to it
    // This is needed to correctly handle some edge cases like ImportList in AvqScript
    // Logic for distinguishing between container's comments and the ones of first element is expected to be implemented in 'isLeadingCommentFor'
    emitContainerComments(from);
  }
  List<INode> result = Lists.newArrayList();
  boolean handleReordering = from.getTotalOffset() > to.getTotalOffset();
  if (!handleReordering) {
    // Elements are not reordered
    // Just going through the interval and collecting comments, unless they have already been emitted
    NodeIterator nodes = new NodeIterator(from);
    while (nodes.hasNext()) {
      INode next = nodes.next();
      if (tokenUtil.isWhitespaceOrCommentNode(next)) {
        if (!emittedComments.contains(next)) {
          result.add(next);
        }
      } else if (next.equals(to)) {
        // We have hit the 'to' node
        // If it is a composite one, we have to iterate through its children
        // and collect whitespaces/comments until we encounter first token (keyword, identifier...)
        if (next instanceof ICompositeNode && (GrammarUtil.isDatatypeRuleCall(next.getGrammarElement())
            || GrammarUtil.isEnumRuleCall(next.getGrammarElement()) || next.getGrammarElement() instanceof CrossReference)) {
          while (nodes.hasNext()) {
            INode lastNodeChild = nodes.next();
            if (tokenUtil.isWhitespaceOrCommentNode(lastNodeChild)) {
              if (!emittedComments.contains(lastNodeChild)) {
                result.add(lastNodeChild);
              }
            } else if (lastNodeChild instanceof ILeafNode) {
              break;
            }
          }
          break;
        } else {
          // 'to' node is not a composite one, nothing to do here, just exit the loop
          break;
        }
      } else if (belongsToDeletedElement(next)) {
        handleDeletedElement(result, deletedSemanticElements, next);
        nodes.prune();
      } else if (tokenUtil.isToken(next)) {
        // We have encountered some token, but not the one we expected
        // Will be handled by invoking 'getLeadingCommentsIncludingWhitespace' method later
        handleReordering = true;
        break;
      }
    }
  }
  if (handleReordering) {
    return getLeadingCommentsIncludingWhitespace(to);
  }
  return result;
}