/*
* 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.CheckLevel;
import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
/**
* Checks for misplaced semicolons, such as
* <pre>
* if (foo()); act_now();
* </pre>
* and generates warnings.
*
*/
final class CheckAccidentalSemicolon extends AbstractPostOrderCallback {
static final DiagnosticType SUSPICIOUS_SEMICOLON = DiagnosticType.warning(
"JSC_SUSPICIOUS_SEMICOLON",
"If this if/for/while really shouldn't have a body, use {}");
private final CheckLevel level;
CheckAccidentalSemicolon(CheckLevel level) {
this.level = level;
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
Node child;
switch (n.getType()) {
case Token.IF:
child = n.getFirstChild().getNext(); // skip the condition child
break;
case Token.WHILE:
case Token.FOR:
child = NodeUtil.getLoopCodeBlock(n);
break;
default:
return; // don't check other types
}
// semicolons cause VOID children. Empty blocks are allowed because
// that's usually intentional, especially with loops.
for (; child != null; child = child.getNext()) {
if ((child.getType() == Token.BLOCK) && (!child.hasChildren())) {
// Only warn on empty blocks that replaced EMPTY nodes. BLOCKs with no
// children are considered OK.
if (child.wasEmptyNode()) {
t.getCompiler().report(
t.makeError(n, level, SUSPICIOUS_SEMICOLON));
}
}
}
}
}