/*
* Copyright 2006 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
import java.util.HashSet;
import java.util.Set;
/**
* Removes try catch finally blocks from a parse tree for easier debugging
* (these statements impact both debugging in IE and sometimes even in FF).
*
*/
class RemoveTryCatch implements CompilerPass {
private final AbstractCompiler compiler;
private final Set<Node> tryNodesContainingReturnStatements;
RemoveTryCatch(AbstractCompiler compiler) {
this.compiler = compiler;
this.tryNodesContainingReturnStatements = new HashSet<Node>();
}
/**
* Do all processing on the root node.
*/
@Override
public void process(Node externs, Node root) {
NodeTraversal.traverse(compiler, root, new RemoveTryCatchCode());
}
private class RemoveTryCatchCode extends AbstractPostOrderCallback {
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getType()) {
case Token.TRY:
// Ignore the try statement if it has the @preserveTry annotation
// (for expected exceptions).
JSDocInfo info = n.getJSDocInfo();
if (info != null && info.shouldPreserveTry()) {
return;
}
Node tryBlock = n.getFirstChild();
Node catchBlock = tryBlock.getNext(); // may be null or empty
Node finallyBlock = catchBlock != null ? catchBlock.getNext() : null;
// Ignore the try statement if it has a finally part and the try
// block contains an early return.
if (finallyBlock != null &&
tryNodesContainingReturnStatements.contains(n)) {
return;
}
// Redeclare vars declared in the catch node to be removed.
if (catchBlock.hasOneChild()) {
NodeUtil.redeclareVarsInsideBranch(catchBlock);
}
// Disconnect the try/catch/finally nodes from the parent
// and each other.
n.detachChildren();
// try node
Node block;
if (!NodeUtil.isStatementBlock(parent)) {
block = new Node(Token.BLOCK);
parent.replaceChild(n, block);
block.addChildToFront(tryBlock);
} else {
parent.replaceChild(n, tryBlock);
block = parent;
}
// finally node
if (finallyBlock != null) {
block.addChildAfter(finallyBlock, tryBlock);
}
compiler.reportCodeChange();
break;
case Token.RETURN:
boolean isInTryBlock = false;
for (Node anc = parent;
anc != null && anc.getType() != Token.FUNCTION;
anc = anc.getParent()) {
if (anc.getType() == Token.TRY) {
tryNodesContainingReturnStatements.add(anc);
break;
}
}
break;
}
}
}
}