/*
* 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.se.checks;
import com.google.common.collect.ImmutableList;
import org.sonar.check.Rule;
import org.sonar.java.matcher.MethodMatcher;
import org.sonar.java.se.CheckerContext;
import org.sonar.java.se.ProgramState;
import org.sonar.java.se.constraint.BooleanConstraint;
import org.sonar.java.se.constraint.ConstraintManager;
import org.sonar.java.se.constraint.ObjectConstraint;
import org.sonar.java.se.symbolicvalues.SymbolicValue;
import org.sonar.plugins.java.api.JavaFileScannerContext;
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.Tree;
import java.util.List;
import java.util.Set;
@Rule(key = "S3655")
public class OptionalGetBeforeIsPresentCheck extends SECheck {
private enum Status implements ObjectConstraint.Status {
PRESENT, NOT_PRESENT
}
@Override
public ProgramState checkPreStatement(CheckerContext context, Tree syntaxNode) {
PreStatementVisitor visitor = new PreStatementVisitor(this, context);
syntaxNode.accept(visitor);
return visitor.programState;
}
private static class OptionalSymbolicValue extends SymbolicValue {
private final SymbolicValue optionalSV;
public OptionalSymbolicValue(int id, SymbolicValue sv) {
super(id);
this.optionalSV = sv;
}
/**
* Will be called only after calling optional.isPresent()
*/
@Override
public List<ProgramState> setConstraint(ProgramState programState, BooleanConstraint booleanConstraint) {
ObjectConstraint<Status> optionalConstraint = (ObjectConstraint<Status>) programState.getConstraint(optionalSV);
if(optionalConstraint == null) {
// Constraint on the optional SV might have been disposed. But is is necessarily non null because NPE check is ran before.
optionalConstraint = ObjectConstraint.notNull();
}
if (isImpossibleState(booleanConstraint, optionalConstraint)) {
return ImmutableList.of();
}
if (optionalConstraint.hasStatus(Status.NOT_PRESENT) || optionalConstraint.hasStatus(Status.PRESENT)) {
return ImmutableList.of(programState);
}
ObjectConstraint newConstraint = booleanConstraint.isTrue() ? optionalConstraint.withStatus(Status.PRESENT) : optionalConstraint.withStatus(Status.NOT_PRESENT);
return ImmutableList.of(programState.addConstraint(optionalSV, newConstraint));
}
private static boolean isImpossibleState(BooleanConstraint booleanConstraint, ObjectConstraint optionalConstraint) {
return (optionalConstraint.hasStatus(Status.PRESENT) && booleanConstraint.isFalse())
|| (optionalConstraint.hasStatus(Status.NOT_PRESENT) && booleanConstraint.isTrue());
}
}
private static class PreStatementVisitor extends CheckerTreeNodeVisitor {
private static final String JAVA_UTIL_OPTIONAL = "java.util.Optional";
private static final MethodMatcher OPTIONAL_GET = MethodMatcher.create().typeDefinition(JAVA_UTIL_OPTIONAL).name("get").withoutParameter();
private static final MethodMatcher OPTIONAL_IS_PRESENT = MethodMatcher.create().typeDefinition(JAVA_UTIL_OPTIONAL).name("isPresent").withoutParameter();
private final CheckerContext context;
private final ConstraintManager constraintManager;
private final SECheck check;
private PreStatementVisitor(SECheck check, CheckerContext context) {
super(context.getState());
this.context = context;
this.constraintManager = context.getConstraintManager();
this.check = check;
}
@Override
public void visitMethodInvocation(MethodInvocationTree tree) {
if (OPTIONAL_IS_PRESENT.matches(tree)) {
constraintManager.setValueFactory(id -> new OptionalSymbolicValue(id, programState.peekValue()));
} else if (OPTIONAL_GET.matches(tree) && presenceHasNotBeenChecked(programState.peekValue())) {
String identifier = getIdentifierPart(tree.methodSelect());
String issueMsg;
String flowMsg;
if (identifier.isEmpty()) {
issueMsg = "Optional#";
flowMsg = "";
} else {
issueMsg = identifier + ".";
flowMsg = identifier + " ";
}
Set<List<JavaFileScannerContext.Location>> flow = FlowComputation.singleton("Optional " + flowMsg + "is accessed", tree.methodSelect());
context.reportIssue(tree, check, "Call \""+ issueMsg + "isPresent()\" before accessing the value.", flow);
programState = null;
}
}
private boolean presenceHasNotBeenChecked(SymbolicValue sv) {
return programState.getConstraintWithStatus(sv, Status.PRESENT) == null;
}
private static String getIdentifierPart(ExpressionTree methodSelect) {
if (methodSelect.is(Tree.Kind.MEMBER_SELECT)) {
ExpressionTree expression = ((MemberSelectExpressionTree) methodSelect).expression();
if (expression.is(Tree.Kind.IDENTIFIER)) {
return ((IdentifierTree) expression).name();
}
}
return "";
}
}
}