private void handleContinue(Node node) {
String label = null;
if (node.hasChildren()) {
label = node.getFirstChild().getString();
}
Node cur;
Node lastJump;
// Similar to handBreak's logic with a few minor variation.
Node parent = node.getParent();
for (cur = node, lastJump = node;
!isContinueTarget(cur, parent, label);
cur = parent, parent = parent.getParent()) {
if (cur.getType() == Token.TRY && NodeUtil.hasFinally(cur)) {
if (lastJump == node) {
createEdge(lastJump, Branch.UNCOND, cur.getLastChild());
} else {
finallyMap.put(lastJump, computeFallThrough(cur.getLastChild()));
}
lastJump = cur;
}
Preconditions.checkState(parent != null, "Cannot find continue target.");
}
Node iter = cur;
if (cur.getChildCount() == 4) {
iter = cur.getFirstChild().getNext().getNext();
}
if (lastJump == node) {
createEdge(node, Branch.UNCOND, iter);
} else {
finallyMap.put(lastJump, iter);
}
}
private void handleReturn(Node node) {
Node lastJump = null;
for (Iterator<Node> iter = exceptionHandler.iterator(); iter.hasNext(); ) {
Node curHandler = iter.next();
if (NodeUtil.isFunction(curHandler)) {
break;
}
if (NodeUtil.hasFinally(curHandler)) {
if (lastJump == null) {
createEdge(node, Branch.UNCOND, curHandler.getLastChild());
} else {
finallyMap.put(lastJump, computeFallThrough(curHandler.getLastChild()));
}
lastJump = curHandler;
}
}
if (node.hasChildren()) {
connectToPossibleExceptionHandler(node, node.getFirstChild());
}
if (lastJump == null) {
createEdge(node, Branch.UNCOND, null);
} else {
finallyMap.put(lastJump, null);
}
}
private void handleBreak(Node node) {
String label = null;
// See if it is a break with label.
if (node.hasChildren()) {
label = node.getFirstChild().getString();
}
Node cur;
Node lastJump;
Node parent = node.getParent();
/*
* Continuously look up the ancestor tree for the BREAK target or the target
* with the corresponding label and connect to it. If along the path we
* discover a FINALLY, we will connect the BREAK to that FINALLY. From then
* on, we will just record the control flow changes in the finallyMap. This
* is due to the fact that we need to connect any node that leaves its own
* FINALLY block to the outer FINALLY or the BREAK's target but those nodes
* are not known yet due to the way we traverse the nodes.
*/
for (cur = node, lastJump = node;
!isBreakTarget(cur, parent, label);
cur = parent, parent = parent.getParent()) {
if (cur.getType() == Token.TRY && NodeUtil.hasFinally(cur)) {
if (lastJump == node) {
createEdge(lastJump, Branch.UNCOND, computeFallThrough(cur.getLastChild()));
} else {
finallyMap.put(lastJump, computeFallThrough(cur.getLastChild()));
}
lastJump = cur;
}
Preconditions.checkState(parent != null, "Cannot find break target.");
}
if (lastJump == node) {
createEdge(lastJump, Branch.UNCOND, computeFollowNode(cur));
} else {
finallyMap.put(lastJump, computeFollowNode(cur));
}
}
/**
* Computes the follow() node of a given node and its parent. There is a side effect when calling
* this function. If this function computed an edge that exists a FINALLY, it'll attempt to
* connect the fromNode to the outer FINALLY according to the finallyMap.
*
* @param fromNode The original source node since {@code node} is changed during recursion.
* @param node The node that follow() should compute.
*/
private Node computeFollowNode(Node fromNode, Node node) {
/*
* This is the case where:
*
* 1. Parent is null implies that we are transferring control to the end of
* the script.
*
* 2. Parent is a function implies that we are transferring control back to
* the caller of the function.
*
* 3. If the node is a return statement, we should also transfer control
* back to the caller of the function.
*
* 4. If the node is root then we have reached the end of what we have been
* asked to traverse.
*
* In all cases we should transfer control to a "symbolic return" node.
* This will make life easier for DFAs.
*/
Node parent = node.getParent();
if (parent == null || parent.getType() == Token.FUNCTION || node == root) {
return null;
}
// If we are just before a IF/WHILE/DO/FOR:
switch (parent.getType()) {
// The follow() of any of the path from IF would be what follows IF.
case Token.IF:
return computeFollowNode(fromNode, parent);
case Token.CASE:
case Token.DEFAULT:
// After the body of a CASE, the control goes to the body of the next
// case, without having to go to the case condition.
if (parent.getNext() != null) {
if (parent.getNext().getType() == Token.CASE) {
return parent.getNext().getFirstChild().getNext();
} else if (parent.getNext().getType() == Token.DEFAULT) {
return parent.getNext().getFirstChild();
} else {
Preconditions.checkState(false, "Not reachable");
}
} else {
return computeFollowNode(fromNode, parent);
}
break;
case Token.FOR:
if (NodeUtil.isForIn(parent)) {
return parent;
} else {
return parent.getFirstChild().getNext().getNext();
}
case Token.WHILE:
case Token.DO:
return parent;
case Token.TRY:
// If we are coming out of the TRY block...
if (parent.getFirstChild() == node) {
if (NodeUtil.hasFinally(parent)) { // and have FINALLY block.
return computeFallThrough(parent.getLastChild());
} else { // and have no FINALLY.
return computeFollowNode(fromNode, parent);
}
// CATCH block.
} else if (NodeUtil.getCatchBlock(parent) == node) {
if (NodeUtil.hasFinally(parent)) { // and have FINALLY block.
return computeFallThrough(node.getNext());
} else {
return computeFollowNode(fromNode, parent);
}
// If we are coming out of the FINALLY block...
} else if (parent.getLastChild() == node) {
for (Node finallyNode : finallyMap.get(parent)) {
createEdge(fromNode, Branch.UNCOND, finallyNode);
}
return computeFollowNode(fromNode, parent);
}
}
// Now that we are done with the special cases follow should be its
// immediate sibling, unless its sibling is a function
Node nextSibling = node.getNext();
// Skip function declarations because control doesn't get pass into it.
while (nextSibling != null && nextSibling.getType() == Token.FUNCTION) {
nextSibling = nextSibling.getNext();
}
if (nextSibling != null) {
return computeFallThrough(nextSibling);
} else {
// If there are no more siblings, control is transfered up the AST.
return computeFollowNode(fromNode, parent);
}
}