/*
* Copyright 2017 Google Inc. All Rights Reserved.
*
* 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.errorprone.bugpatterns;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matchers;
import com.sun.source.tree.BlockTree;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
/** Base of checks for explicit and implicit leaks of the 'this' reference. */
abstract class ConstructorLeakChecker extends BugChecker implements ClassTreeMatcher {
/**
* For each class, visits constructors, instance variables, and instance initializers. Delegates
* further scanning of these "constructor-scope" constructs to {@link #traverse}.
*/
@Override
public Description matchClass(ClassTree tree, VisitorState state) {
// TODO(b/36395371): filter here to exclude some classes (e.g. not immutable)
for (Tree member : tree.getMembers()) {
if ((member instanceof MethodTree
&& Matchers.methodIsConstructor().matches((MethodTree) member, state))
|| (member instanceof BlockTree && !((BlockTree) member).isStatic())
|| (member instanceof VariableTree && !Matchers.isStatic().matches(member, state))) {
traverse(member, state);
}
}
return NO_MATCH;
}
/**
* Given a tree that has been determined to be at constructor scope, walks it looking for
* problems. Emits error descriptions as it goes via {@link VisitorState#reportMatch}.
*/
protected abstract void traverse(Tree tree, VisitorState state);
}