/*
* Copyright 2013 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.BugPattern.Category.JDK;
import static com.google.errorprone.BugPattern.MaturityLevel.MATURE;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.tree.JCTree;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
/**
* Matches the behaviour of javac's overrides Xlint warning.
*
* @author cushon@google.com (Liam Miller-Cushon)
*/
@BugPattern(name = "Overrides", altNames = "overrides",
summary = "Varargs doesn't agree for overridden method",
explanation = "A varargs method is overridden by a method with an array parameter, or vice "
+ "versa. Please match the signature of the method being overridden.",
category = JDK, severity = ERROR, maturity = MATURE)
public class Overrides extends BugChecker implements MethodTreeMatcher {
@Override
public Description matchMethod(MethodTree methodTree, VisitorState state) {
MethodSymbol methodSymbol = (MethodSymbol) ASTHelpers.getSymbol(methodTree);
boolean isVarargs = (methodSymbol.flags() & Flags.VARARGS) != 0;
Set<MethodSymbol> superMethods = ASTHelpers.findSuperMethods(methodSymbol, state.getTypes());
// If there are no super methods, we're fine:
if (superMethods.isEmpty()) {
return Description.NO_MATCH;
}
Iterator<MethodSymbol> superMethodsIterator = superMethods.iterator();
boolean areSupersVarargs = superMethodsIterator.next().isVarArgs();
while (superMethodsIterator.hasNext()) {
if (areSupersVarargs != superMethodsIterator.next().isVarArgs()) {
// The super methods are inconsistent (some are varargs, some are not varargs). Then the
// current method is inconsistent with some of its supermethods, so report a match.
return describeMatch(methodTree);
}
}
// The current method is consistent with all of its supermethods:
if (isVarargs == areSupersVarargs) {
return Description.NO_MATCH;
}
// The current method is inconsistent with all of its supermethods, so flip the varargs-ness
// of the current method.
List<? extends VariableTree> parameterTree = methodTree.getParameters();
Tree paramType = parameterTree.get(parameterTree.size() - 1).getType();
CharSequence paramTypeSource = state.getSourceForNode((JCTree) paramType);
if (paramTypeSource == null) {
// No fix if we don't have tree end positions.
return describeMatch(methodTree);
}
Description.Builder descriptionBuilder = Description.builder(methodTree, pattern);
if (isVarargs) {
descriptionBuilder.addFix(
SuggestedFix.replace(paramType, "[]", paramTypeSource.length() - 3, 0));
} else {
// There may be a comment that includes a '[' character between the open and closed
// brackets of the array type. If so, we don't return a fix.
int arrayOpenIndex = paramTypeSource.length() - 2;
while (paramTypeSource.charAt(arrayOpenIndex) == ' ') {
arrayOpenIndex--;
}
if (paramTypeSource.charAt(arrayOpenIndex) == '[') {
descriptionBuilder.addFix(
SuggestedFix.replace(paramType, "...", arrayOpenIndex, 0));
}
}
return descriptionBuilder.build();
}
}