Java Code Examples for com.google.javascript.rhino.Node#isSyntheticBlock()

/**
 * Try removing unneeded block nodes and their useless children
 */
void tryFoldBlock(NodeTraversal t, Node n, Node parent) {
  // Remove any useless children
  for (Node c = n.getFirstChild(); c != null; ) {
    Node next = c.getNext();  // save c.next, since 'c' may be removed
    if (!NodeUtil.mayHaveSideEffects(c)) {
      n.removeChild(c);  // lazy kids
      t.getCompiler().reportCodeChange();
    }
    c = next;
  }

  if (n.isSyntheticBlock() || parent == null) {
    return;
  }

  // Try to remove the block.
  if (NodeUtil.tryMergeBlock(n)) {
    t.getCompiler().reportCodeChange();
  }
}
 

/**
 * Try removing unneeded block nodes and their useless children
 */
void tryFoldBlock(NodeTraversal t, Node n, Node parent) {
  // Remove any useless children
  for (Node c = n.getFirstChild(); c != null; ) {
    Node next = c.getNext();  // save c.next, since 'c' may be removed
    if (!NodeUtil.mayHaveSideEffects(c)) {
      n.removeChild(c);  // lazy kids
      t.getCompiler().reportCodeChange();
    }
    c = next;
  }

  if (n.isSyntheticBlock() || parent == null) {
    return;
  }

  // Try to remove the block.
  if (NodeUtil.tryMergeBlock(n)) {
    t.getCompiler().reportCodeChange();
  }
}
 

/**
 * Check if the specified node is null or is still in the AST.
 */
@VisibleForTesting
static Node validateResult(Node n) {
  done: {
    if (n != null && !n.isScript()
        && (!n.isBlock() || !n.isSyntheticBlock())) {
      for (Node parent : n.getAncestors()) {
        if (parent.isScript()) {
          break done;
        }
      }
      Preconditions.checkState(false);
    }
  }
  return n;
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.isBlock() && parent != null &&
      parent.isTry() &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.isFunction()) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node, this));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT_CASE:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.isBlock() && node.isSyntheticBlock()) {
          createEdge(node, Branch.SYN_BLOCK, computeFollowNode(node, this));
        }
        break;
    }
  }
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.isBlock() && parent != null &&
      parent.isTry() &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.isFunction()) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node, this));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT_CASE:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.isBlock() && node.isSyntheticBlock()) {
          createEdge(node, Branch.SYN_BLOCK, computeFollowNode(node, this));
        }
        break;
    }
  }
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.isBlock() && parent != null &&
      parent.isTry() &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.isFunction()) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node, this));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT_CASE:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.isBlock() && node.isSyntheticBlock()) {
          createEdge(node, Branch.SYN_BLOCK, computeFollowNode(node, this));
        }
        break;
    }
  }
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.isBlock() && parent != null &&
      parent.isTry() &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.isFunction()) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node, this));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT_CASE:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.isBlock() && node.isSyntheticBlock()) {
          createEdge(node, Branch.SYN_BLOCK, computeFollowNode(node, this));
        }
        break;
    }
  }
}
 

/**
 * Try removing unneeded block nodes and their useless children
 */
Node tryOptimizeBlock(Node n) {
  // Remove any useless children
  for (Node c = n.getFirstChild(); c != null; ) {
    Node next = c.getNext();  // save c.next, since 'c' may be removed
    if (!isUnremovableNode(c) && !mayHaveSideEffects(c)) {
      // TODO(johnlenz): determine what this is actually removing. Candidates
      //    include: EMPTY nodes, control structures without children
      //    (removing infinite loops), empty try blocks.  What else?
      n.removeChild(c);  // lazy kids
      reportCodeChange();
    } else {
      tryOptimizeConditionalAfterAssign(c);
    }
    c = next;
  }

  if (n.isSyntheticBlock() ||  n.getParent() == null) {
    return n;
  }

  // Try to remove the block.
  if (NodeUtil.tryMergeBlock(n)) {
    reportCodeChange();
    return null;
  }

  return n;
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.isBlock() && parent != null &&
      parent.isTry() &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.isFunction()) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node, this));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT_CASE:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.isBlock() && node.isSyntheticBlock()) {
          createEdge(node, Branch.SYN_BLOCK, computeFollowNode(node, this));
        }
        break;
    }
  }
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.getType() == Token.BLOCK && parent != null &&
      parent.getType() == Token.TRY &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.getType() == Token.FUNCTION) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.getType() == Token.BLOCK && node.isSyntheticBlock()) {
          Node next = node.getLastChild();
          if (next != null) {
            createEdge(node, Branch.SYN_BLOCK, computeFallThrough(next));
          }
        }
        break;
    }
  }
}
 

private void handleStmtList(Node node) {
  Node parent = node.getParent();
  // Special case, don't add a block of empty CATCH block to the graph.
  if (node.getType() == Token.BLOCK && parent != null &&
      parent.getType() == Token.TRY &&
      NodeUtil.getCatchBlock(parent) == node &&
      !NodeUtil.hasCatchHandler(node)) {
    return;
  }

  // A block transfer control to its first child if it is not empty.
  Node child = node.getFirstChild();

  // Function declarations are skipped since control doesn't go into that
  // function (unless it is called)
  while (child != null && child.getType() == Token.FUNCTION) {
    child = child.getNext();
  }

  if (child != null) {
    createEdge(node, Branch.UNCOND, computeFallThrough(child));
  } else {
    createEdge(node, Branch.UNCOND, computeFollowNode(node));
  }

  // Synthetic blocks
  if (parent != null) {
    switch (parent.getType()) {
      case Token.DEFAULT:
      case Token.CASE:
      case Token.TRY:
        break;
      default:
        if (node.getType() == Token.BLOCK && node.isSyntheticBlock()) {
          Node next = node.getLastChild();
          if (next != null) {
            createEdge(node, Branch.SYN_BLOCK, computeFallThrough(next));
          }
        }
        break;
    }
  }
}
 

/**
 * Some nodes unremovable node don't have side-effects.
 */
private boolean isUnremovableNode(Node n) {
  return (n.isBlock() && n.isSyntheticBlock()) || n.isScript();
}