private static boolean isLeftShiftOnOne(BinaryExpressionTree tree) {
// 1 << 1 is used for bit masks construction and should be excluded.
if (tree.is(Tree.Kind.LEFT_SHIFT)
&& tree.leftOperand().is(Tree.Kind.INT_LITERAL)
&& tree.rightOperand().is(Tree.Kind.INT_LITERAL)) {
String left = ((LiteralTree) tree.leftOperand()).value();
String right = ((LiteralTree) tree.rightOperand()).value();
if ("1".equals(right) && "1".equals(left)) {
return true;
}
}
return false;
}
public static boolean hasEquivalentOperand(BinaryExpressionTree tree) {
if (isNanTest(tree) || isLeftShiftOnOne(tree)) {
return false;
}
Tree.Kind binaryKind = tree.kind();
return areOperandEquivalent(tree.leftOperand(), tree.rightOperand(), binaryKind);
}
@Override
public void visitBinaryExpression(BinaryExpressionTree tree) {
if (tree.is(Kind.PLUS)) {
checkConcatenation(tree, tree.leftOperand(), tree.rightOperand());
}
super.visitBinaryExpression(tree);
}
private void buildConditionalAnd(
BinaryExpressionTree conditionalAnd, Block trueBlock, Block falseBlock) {
buildCondition(conditionalAnd.rightOperand(), trueBlock, falseBlock);
Block newTrueBlock = currentBlock;
// process LHS
currentBlock = createBranch(conditionalAnd, newTrueBlock, falseBlock);
buildCondition(conditionalAnd.leftOperand(), newTrueBlock, falseBlock);
}
private void buildConditionalOr(
BinaryExpressionTree conditionalOr, Block trueBlock, Block falseBlock) {
// process RHS
buildCondition(conditionalOr.rightOperand(), trueBlock, falseBlock);
Block newFalseBlock = currentBlock;
// process LHS
currentBlock = createBranch(conditionalOr, trueBlock, newFalseBlock);
buildCondition(conditionalOr.leftOperand(), trueBlock, newFalseBlock);
}
private void buildConditionalOr(BinaryExpressionTree tree) {
// process RHS
Block trueBlock = currentBlock;
currentBlock = createBlock(trueBlock);
build(tree.rightOperand());
Block falseBlock = currentBlock;
// process LHS
currentBlock = createBranch(tree, trueBlock, falseBlock);
build(tree.leftOperand());
}
@Override
public void visitNode(Tree tree) {
BinaryExpressionTree bet = (BinaryExpressionTree) tree;
if (bet.leftOperand().is(Tree.Kind.STRING_LITERAL)
|| bet.rightOperand().is(Tree.Kind.STRING_LITERAL)) {
addIssue(
tree,
"Replace \"==\" and \"!=\" by \"equals()\" and \"!equals()\" respectively to compare these strings.");
}
}
@Override
public void visitNode(Tree tree) {
BinaryExpressionTree binaryExpressionTree = (BinaryExpressionTree) tree;
if (hasEquivalentOperand(binaryExpressionTree)) {
addIssue(
binaryExpressionTree.rightOperand(),
"Identical sub-expressions on both sides of operator \""
+ binaryExpressionTree.operatorToken().text()
+ "\"");
}
}
@Override
public void visitNode(Tree tree) {
BinaryExpressionTree binaryExpressionTree = (BinaryExpressionTree) tree;
if (binaryExpressionTree.is(Tree.Kind.CONDITIONAL_AND, Tree.Kind.CONDITIONAL_OR)
&& isIndirectEquality(binaryExpressionTree)) {
binaryExpressionTree = (BinaryExpressionTree) binaryExpressionTree.leftOperand();
}
if ((hasFloatingType(binaryExpressionTree.leftOperand())
|| hasFloatingType(binaryExpressionTree.rightOperand()))
&& !isNanTest(binaryExpressionTree)) {
addIssue(
binaryExpressionTree, "Equality tests should not be made with floating point values.");
}
}
@Override
public void visitBinaryExpression(BinaryExpressionTree tree) {
super.visitBinaryExpression(tree);
if (tree.is(Tree.Kind.EQUAL_TO)) {
Type leftOperandType = ((JavaTree.AbstractExpressionTree) tree.leftOperand()).getType();
Type rightOperandType = ((JavaTree.AbstractExpressionTree) tree.rightOperand()).getType();
if (leftOperandType == null || rightOperandType == null) {
// FIXME null type should not happen.
return;
}
if (!isNullComparison(leftOperandType, rightOperandType)
&& (isClass(leftOperandType) || isClass(rightOperandType))) {
context.addIssue(tree, ruleKey, "Change this comparison to use the equals method.");
}
}
}
@Override
public void visitBinaryExpression(BinaryExpressionTree tree) {
super.visitBinaryExpression(tree);
if (isShifting(tree)) {
shifts.add(tree);
return;
}
if (isSecuringByte(tree)) {
byteContainments.add(tree);
return;
}
if (isIntegerOrLongExpected(tree.symbolType())) {
ExpressionTree leftOperand = ExpressionUtils.skipParentheses(tree.leftOperand());
ExpressionTree rightOperand = ExpressionUtils.skipParentheses(tree.rightOperand());
checkShiftWithoutByteSecuring(leftOperand, rightOperand);
checkShiftWithoutByteSecuring(rightOperand, leftOperand);
}
}
private static boolean isIndirectEquality(
BinaryExpressionTree binaryExpressionTree,
Tree.Kind indirectOperator,
Tree.Kind comparator1,
Tree.Kind comparator2) {
if (binaryExpressionTree.is(indirectOperator)
&& binaryExpressionTree.leftOperand().is(comparator1, comparator2)) {
BinaryExpressionTree leftOp = (BinaryExpressionTree) binaryExpressionTree.leftOperand();
if (binaryExpressionTree.rightOperand().is(comparator1, comparator2)) {
BinaryExpressionTree rightOp = (BinaryExpressionTree) binaryExpressionTree.rightOperand();
if (((JavaTree) leftOp).getKind().equals(((JavaTree) rightOp).getKind())) {
// same operator
return SyntacticEquivalence.areEquivalent(leftOp.leftOperand(), rightOp.rightOperand())
&& SyntacticEquivalence.areEquivalent(leftOp.rightOperand(), rightOp.leftOperand());
} else {
// different operator
return SyntacticEquivalence.areEquivalent(leftOp.leftOperand(), rightOp.leftOperand())
&& SyntacticEquivalence.areEquivalent(leftOp.rightOperand(), rightOp.rightOperand());
}
}
}
return false;
}
private static boolean isNanTest(BinaryExpressionTree binaryExpressionTree) {
return SyntacticEquivalence.areEquivalent(
binaryExpressionTree.leftOperand(), binaryExpressionTree.rightOperand());
}
private void buildBinaryExpression(Tree tree) {
BinaryExpressionTree binaryExpressionTree = (BinaryExpressionTree) tree;
currentBlock.elements.add(tree);
build(binaryExpressionTree.rightOperand());
build(binaryExpressionTree.leftOperand());
}
private static boolean isSecuringByte(BinaryExpressionTree tree) {
return tree.is(Tree.Kind.AND) && (is0xff(tree.rightOperand()) || is0xff(tree.leftOperand()));
}