/*
* SonarQube Java
* Copyright (C) 2012-2016 SonarSource SA
* mailto:contact AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.sonar.java.checks;
import com.google.common.collect.ImmutableList;
import org.sonar.check.Rule;
import org.sonar.java.matcher.MethodMatcher;
import org.sonar.java.matcher.NameCriteria;
import org.sonar.plugins.java.api.JavaFileScanner;
import org.sonar.plugins.java.api.JavaFileScannerContext;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.semantic.Type;
import org.sonar.plugins.java.api.tree.AssignmentExpressionTree;
import org.sonar.plugins.java.api.tree.BaseTreeVisitor;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.MemberSelectExpressionTree;
import org.sonar.plugins.java.api.tree.MethodInvocationTree;
import org.sonar.plugins.java.api.tree.MethodTree;
import org.sonar.plugins.java.api.tree.ReturnStatementTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.VariableTree;
import java.util.ArrayList;
import java.util.Deque;
import java.util.LinkedList;
import java.util.List;
@Rule(key = "S2384")
public class MutableMembersUsageCheck extends BaseTreeVisitor implements JavaFileScanner {
private static final List<String> MUTABLE_TYPES = ImmutableList.of(
"java.util.Collection",
"java.util.Date",
"java.util.Hashtable");
private static final List<String> IMMUTABLE_TYPES = ImmutableList.of(
"java.util.Collections.UnmodifiableCollection",
"java.util.Collections.UnmodifiableMap",
"com.google.common.collect.ImmutableCollection");
private static final MethodMatcher UNMODIFIABLE_COLLECTION_CALL = MethodMatcher.create().typeDefinition("java.util.Collections").name(NameCriteria.startsWith("unmodifiable"))
.withAnyParameters();
private JavaFileScannerContext context;
private Deque<List<Symbol>> parametersStack = new LinkedList<>();
@Override
public void scanFile(final JavaFileScannerContext context) {
this.context = context;
scan(context.getTree());
}
@Override
public void visitMethod(MethodTree tree) {
ArrayList<Symbol> parameters = new ArrayList<>();
for (VariableTree variableTree : tree.parameters()) {
parameters.add(variableTree.symbol());
}
parametersStack.push(parameters);
super.visitMethod(tree);
parametersStack.pop();
}
@Override
public void visitAssignmentExpression(AssignmentExpressionTree tree) {
super.visitAssignmentExpression(tree);
if (!isMutableType(tree.expression())) {
return;
}
ExpressionTree variable = tree.variable();
Symbol leftSymbol = null;
if (variable.is(Tree.Kind.IDENTIFIER)) {
IdentifierTree identifierTree = (IdentifierTree) variable;
leftSymbol = identifierTree.symbol();
} else if (variable.is(Tree.Kind.MEMBER_SELECT)) {
MemberSelectExpressionTree mit = (MemberSelectExpressionTree) variable;
leftSymbol = mit.identifier().symbol();
}
if (leftSymbol != null && leftSymbol.isPrivate()) {
checkStore(tree.expression());
}
}
@Override
public void visitVariable(VariableTree tree) {
super.visitVariable(tree);
ExpressionTree initializer = tree.initializer();
if (initializer == null || !isMutableType(initializer)) {
return;
}
checkStore(initializer);
}
private void checkStore(ExpressionTree expression) {
if (expression.is(Tree.Kind.IDENTIFIER)) {
IdentifierTree identifierTree = (IdentifierTree) expression;
if (!parametersStack.isEmpty() && parametersStack.peek().contains(identifierTree.symbol())) {
context.reportIssue(this, identifierTree, "Store a copy of \"" + identifierTree.name() + "\".");
}
}
}
@Override
public void visitReturnStatement(ReturnStatementTree tree) {
super.visitReturnStatement(tree);
ExpressionTree expressionTree = tree.expression();
if (expressionTree == null || !isMutableType(expressionTree)) {
return;
}
if (expressionTree.is(Tree.Kind.IDENTIFIER)) {
IdentifierTree identifierTree = (IdentifierTree) expressionTree;
if (identifierTree.symbol().isPrivate() && !isImmutableConstant((Symbol.VariableSymbol) identifierTree.symbol())) {
context.reportIssue(this, identifierTree, "Return a copy of \"" + identifierTree.name() + "\".");
}
}
}
private static boolean isImmutableConstant(Symbol.VariableSymbol symbol) {
if (symbol.isStatic() && symbol.isFinal()) {
VariableTree declaration = symbol.declaration();
// symbol is private, so declaration can only be null if assignment is done in static block
if (declaration.initializer() != null) {
return !isMutableType(declaration.initializer());
}
return !assignementsOfMutableType(symbol.usages());
}
return false;
}
private static boolean assignementsOfMutableType(List<IdentifierTree> usages) {
for (IdentifierTree usage : usages) {
Tree current = usage;
Tree parent = usage.parent();
do {
if (parent.is(Tree.Kind.ASSIGNMENT)) {
break;
}
current = parent;
parent = current.parent();
} while (parent != null);
if (parent != null) {
AssignmentExpressionTree assignment = (AssignmentExpressionTree) parent;
if (assignment.variable().equals(current) && isMutableType(assignment.expression())) {
return true;
}
}
}
return false;
}
private static boolean isMutableType(ExpressionTree expressionTree) {
if (expressionTree.is(Tree.Kind.METHOD_INVOCATION) && UNMODIFIABLE_COLLECTION_CALL.matches((MethodInvocationTree) expressionTree)) {
return false;
}
return isMutableType(expressionTree.symbolType());
}
private static boolean isMutableType(Type type) {
if (type.isArray()) {
return true;
}
for (String mutableType : MUTABLE_TYPES) {
if (type.isSubtypeOf(mutableType) && isNotImmutable(type)) {
return true;
}
}
return false;
}
private static boolean isNotImmutable(Type type) {
for (String immutableType : IMMUTABLE_TYPES) {
if (type.isSubtypeOf(immutableType)) {
return false;
}
}
return true;
}
}