/*******************************************************************************
* Copyright (c) 2018 GK Software SE and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Stephan Herrmann - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;
import static org.eclipse.jdt.internal.compiler.ast.ExpressionContext.ASSIGNMENT_CONTEXT;
import static org.eclipse.jdt.internal.compiler.ast.ExpressionContext.INVOCATION_CONTEXT;
import static org.eclipse.jdt.internal.compiler.ast.ExpressionContext.VANILLA_CONTEXT;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.impl.Constant;
import org.eclipse.jdt.internal.compiler.lookup.Binding;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment;
import org.eclipse.jdt.internal.compiler.lookup.MethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.PolyTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.Scope;
import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities;
public class SwitchExpression extends SwitchStatement implements IPolyExpression {
/* package */ TypeBinding expectedType;
private ExpressionContext expressionContext = VANILLA_CONTEXT;
private boolean isPolyExpression = false;
private TypeBinding[] originalValueResultExpressionTypes;
private TypeBinding[] finalValueResultExpressionTypes;
public List<Expression> resultExpressions;
@Override
public void setExpressionContext(ExpressionContext context) {
this.expressionContext = context;
}
@Override
public void setExpectedType(TypeBinding expectedType) {
this.expectedType = expectedType;
}
@Override
public ExpressionContext getExpressionContext() {
return this.expressionContext;
}
@Override
protected int getFallThroughState(Statement stmt, BlockScope blockScope) {
if (stmt instanceof Expression || stmt instanceof ThrowStatement)
return BREAKING;
if (stmt instanceof Block) {
Block block = (Block) stmt;
if (block.doesNotCompleteNormally()) {
return BREAKING;
}
//JLS 12 15.29.1 Given a switch expression, if the switch block consists of switch labeled rules,
//then it is a compile-time error if any switch labeled block can complete normally.
blockScope.problemReporter().switchExpressionBlockCompletesNormally(block);
}
return FALLTHROUGH;
}
@Override
public Expression[] getPolyExpressions() {
List<Expression> polys = new ArrayList<>();
for (Expression e : this.resultExpressions) {
Expression[] ea = e.getPolyExpressions();
if (ea == null || ea.length ==0) continue;
polys.addAll(Arrays.asList(ea));
}
return polys.toArray(new Expression[0]);
}
@Override
public boolean isPertinentToApplicability(TypeBinding targetType, MethodBinding method) {
for (Expression e : this.resultExpressions) {
if (!e.isPertinentToApplicability(targetType, method))
return false;
}
return true;
}
@Override
public boolean isPotentiallyCompatibleWith(TypeBinding targetType, Scope scope1) {
for (Expression e : this.resultExpressions) {
if (!e.isPotentiallyCompatibleWith(targetType, scope1))
return false;
}
return true;
}
@Override
public boolean isFunctionalType() {
for (Expression e : this.resultExpressions) {
if (e.isFunctionalType())
return true;
}
return false;
}
@Override
public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
// TODO
}
protected boolean computeConversions(BlockScope blockScope, TypeBinding targetType) {
boolean ok = true;
for (int i = 0, l = this.resultExpressions.size(); i < l; ++i) {
ok = computeConversionsResultExpressions(blockScope, targetType, ok, this.originalValueResultExpressionTypes[i],
this.resultExpressions.get(i));
}
return ok;
}
private boolean computeConversionsResultExpressions(BlockScope blockScope, TypeBinding targetType, boolean ok,
TypeBinding resultExpressionType, Expression resultExpression) {
if (resultExpressionType != null && resultExpressionType.isValidBinding()) {
if (resultExpression.isConstantValueOfTypeAssignableToType(resultExpressionType, targetType)
|| resultExpressionType.isCompatibleWith(targetType)) {
resultExpression.computeConversion(blockScope, targetType, resultExpressionType);
if (resultExpressionType.needsUncheckedConversion(targetType)) {
blockScope.problemReporter().unsafeTypeConversion(resultExpression, resultExpressionType, targetType);
}
if (resultExpression instanceof CastExpression
&& (resultExpression.bits & (ASTNode.UnnecessaryCast|ASTNode.DisableUnnecessaryCastCheck)) == 0) {
CastExpression.checkNeedForAssignedCast(blockScope, targetType, (CastExpression) resultExpression);
}
} else if (isBoxingCompatible(resultExpressionType, targetType, resultExpression, blockScope)) {
resultExpression.computeConversion(blockScope, targetType, resultExpressionType);
if (resultExpression instanceof CastExpression
&& (resultExpression.bits & (ASTNode.UnnecessaryCast|ASTNode.DisableUnnecessaryCastCheck)) == 0) {
CastExpression.checkNeedForAssignedCast(blockScope, targetType, (CastExpression) resultExpression);
}
} else {
blockScope.problemReporter().typeMismatchError(resultExpressionType, targetType, resultExpression, null);
ok = false;
}
}
return ok;
}
private void collectResultExpressions() {
if (this.resultExpressions != null)
return; // already calculated.
class ResultExpressionsCollector extends ASTVisitor {
SwitchExpression targetSwitchExpression;
public ResultExpressionsCollector(SwitchExpression se) {
this.targetSwitchExpression = se;
}
@Override
public boolean visit(SwitchExpression switchExpression, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(BreakStatement breakStatement, BlockScope blockScope) {
if (breakStatement.expression != null) {
this.targetSwitchExpression.resultExpressions.add(breakStatement.expression);
breakStatement.switchExpression = this.targetSwitchExpression;
}
return false;
}
@Override
public boolean visit(DoStatement stmt, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(ForStatement stmt, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(ForeachStatement stmt, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(SwitchStatement stmt, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(TypeDeclaration stmt, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(WhileStatement stmt, BlockScope blockScope) {
return false;
}
@Override
public boolean visit(CaseStatement caseStatement, BlockScope blockScope) {
return true; // do nothing by default, keep traversing
}
}
this.resultExpressions = new ArrayList<>(0); // indicates processed
for (int i = 0, l = this.statements.length; i < l; ++i) {
Statement stmt = this.statements[i];
if (stmt instanceof CaseStatement) {
CaseStatement caseStatement = (CaseStatement) stmt;
if (!caseStatement.isExpr) continue;
stmt = this.statements[++i];
if (stmt instanceof Expression) {
this.resultExpressions.add((Expression) stmt);
continue;
} else if (stmt instanceof ThrowStatement) {
// TODO: Throw Expression Processing. Anything to be done here for resolve?
continue;
}
}
// break statement and block statement of SwitchLabelRule or block statement of ':'
ResultExpressionsCollector reCollector = new ResultExpressionsCollector(this);
stmt.traverse(reCollector, this.scope);
/*TODO: Do the following error check in analyseCode() rather than here - JLS 12 15.29
* Given a switch expression, if the switch block consists of switch labeled rules, then
* it is a compile-time error if any switch labeled block can complete normally. If, on the
* other hand, the switch block consists of switch labeled statement groups, then it is a
* compile-time error if either the last statement in the switch block can complete
* normally, or the switch block includes one or more switch labels at the end.
*/
}
}
@Override
public TypeBinding resolveType(BlockScope upperScope) {
try {
// JLS12 15.29.1
CompilerOptions compilerOptions = upperScope.compilerOptions();
this.scope = new BlockScope(upperScope);
LookupEnvironment env = this.scope.environment();
resolve(upperScope);
if (this.statements == null || this.statements.length == 0) {
// Report Error JLS 12 15.29.1 The switch block must not be empty.
upperScope.problemReporter().switchExpressionEmptySwitchBlock(this);
return null;
}
if (this.defaultCase == null) {
if (compilerOptions.getSeverity(CompilerOptions.MissingDefaultCase) == ProblemSeverities.Ignore) {
TypeBinding expressionType = this.expression.resolvedType;
if (!expressionType.isEnum()) {
// cannot ignore in SwitchExpressions - this is a compile-time error
// it was not reported earlier in super.resolve() since it was ignored.
upperScope.problemReporter().missingDefaultCase(this, false /* isEnumSwitch*/, expressionType);
}
}
}
// now we are done with case constants, let us collect the result expressions
collectResultExpressions();
int resultExpressionsCount = this.resultExpressions != null ? this.resultExpressions.size() : 0;
if (resultExpressionsCount == 0) {
// Report Error JLS 12 15.29.1
// It is a compile-time error if a switch expression has no result expressions.
upperScope.problemReporter().switchExpressionNoResultExpressions(this);
return null;
}
//A switch expression is a poly expression if it appears in an assignment context or an invocation context (5.2, 5.3).
//Otherwise, it is a standalone expression.
if (this.expressionContext == ASSIGNMENT_CONTEXT || this.expressionContext == INVOCATION_CONTEXT) {
for (Expression e : this.resultExpressions) {
//Where a poly switch expression appears in a context of a particular kind with target type T,
//its result expressions similarly appear in a context of the same kind with target type T.
e.setExpressionContext(this.expressionContext);
e.setExpectedType(this.expectedType);
}
}
if (this.constant != Constant.NotAConstant) {
this.constant = Constant.NotAConstant;
this.originalValueResultExpressionTypes = new TypeBinding[resultExpressionsCount];
for (int i = 0; i < resultExpressionsCount; ++i) {
this.originalValueResultExpressionTypes[i] = this.resultExpressions.get(i).resolveType(this.scope);
}
// TODO: should we return if one of the types is null? to check
} else {
for (int i = 0; i < resultExpressionsCount; ++i) {
if (this.originalValueResultExpressionTypes[i].kind() == Binding.POLY_TYPE)
this.originalValueResultExpressionTypes[i] = this.resultExpressions.get(i).resolveType(this.scope);
}
// TODO: should we return if one of the types is null? to check
}
this.finalValueResultExpressionTypes = new TypeBinding[resultExpressionsCount];
for (int i = 0; i < resultExpressionsCount; ++i)
this.finalValueResultExpressionTypes[i] = this.originalValueResultExpressionTypes[i];
if (isPolyExpression()) { //The type of a poly switch expression is the same as its target type.
if (this.expectedType == null || !this.expectedType.isProperType(true)) {
return new PolyTypeBinding(this);
}
return this.resolvedType = computeConversions(this.scope, this.expectedType) ? this.expectedType : null;
}
if (resultExpressionsCount == 1)
return this.originalValueResultExpressionTypes[0];
boolean typeUniformAcrossAllArms = true;
TypeBinding tmp = this.originalValueResultExpressionTypes[0];
for (int i = 1, l = this.originalValueResultExpressionTypes.length; i < l; ++i) {
if (TypeBinding.notEquals(tmp, this.originalValueResultExpressionTypes[i])) {
typeUniformAcrossAllArms = false;
break;
}
}
// If the result expressions all have the same type (which may be the null type),
// then that is the type of the switch expression.
if (typeUniformAcrossAllArms) {
tmp = this.originalValueResultExpressionTypes[0];
for (int i = 0; i < resultExpressionsCount; ++i) {
tmp = NullAnnotationMatching.moreDangerousType(tmp, this.originalValueResultExpressionTypes[i]);
}
return this.resolvedType = tmp;
}
boolean typeBbolean = true;
for (TypeBinding t : this.originalValueResultExpressionTypes) {
typeBbolean &= t.id == T_boolean || t.id == T_JavaLangBoolean;
}
/*
* Otherwise, if the type of each result expression is boolean or Boolean,
* an unboxing conversion (5.1.8) is applied to each result expression of type Boolean,
* and the switch expression has type boolean.
*/
if (typeBbolean) {
for (int i = 0; i < resultExpressionsCount; ++i) {
if (this.originalValueResultExpressionTypes[i].id == T_boolean) continue;
this.finalValueResultExpressionTypes[i] = env.computeBoxingType(this.originalValueResultExpressionTypes[i]);
this.resultExpressions.get(i).computeConversion(this.scope, this.finalValueResultExpressionTypes[i], this.originalValueResultExpressionTypes[i]);
}
return this.resolvedType = TypeBinding.BOOLEAN;
}
/*
* Otherwise, if the type of each result expression is convertible to a numeric type (5.1.8),
* the type of the switch expression is given by numeric promotion (5.6.3) applied to the result expressions.
*/
boolean typeNumeric = true;
TypeBinding resultNumeric = this.originalValueResultExpressionTypes[0];
HashSet<TypeBinding> typeSet = new HashSet<>(); // for inconclusive in first attempt
for (int i = 0; i < resultExpressionsCount; ++i) {
tmp = this.originalValueResultExpressionTypes[i].isNumericType() ?
this.originalValueResultExpressionTypes[i] :
env.computeBoxingType(this.originalValueResultExpressionTypes[i]);
if (!tmp.isNumericType()) {
typeNumeric = false;
break;
}
resultNumeric = getFirstResults(tmp, this.resultExpressions.get(i), resultNumeric);
typeSet.add(TypeBinding.wellKnownType(this.scope, tmp.id));
}
if (typeNumeric) {
resultNumeric = resultNumeric != null ? resultNumeric :
getResultNumeric(typeSet, this.originalValueResultExpressionTypes);
typeSet = null; // hey gc!
for (int i = 0; i < resultExpressionsCount; ++i) {
// auto-unboxing and/or widening/narrrowing JLS 12 5.6.3
this.resultExpressions.get(i).computeConversion(this.scope,
resultNumeric, this.originalValueResultExpressionTypes[i]);
this.finalValueResultExpressionTypes[i] = resultNumeric;
}
// After the conversion(s), if any, value set conversion (5.1.13) is then applied to each result expression.
// TODO: check whether 5.6.3 automatically done - check CE.resolveType() as well.
return this.resolvedType = resultNumeric;
}
/* Otherwise, boxing conversion (5.1.7) is applied to each result expression that has a primitive type,
* after which the type of the switch expression is the result of applying capture conversion (5.1.10)
* to the least upper bound (4.10.4) of the types of the result expressions.
*/
for (int i = 0; i < resultExpressionsCount; ++i) {
if (this.finalValueResultExpressionTypes[i].isBaseType())
this.finalValueResultExpressionTypes[i] = env.computeBoxingType(this.finalValueResultExpressionTypes[i]);
}
TypeBinding commonType = this.scope.lowerUpperBound(this.finalValueResultExpressionTypes);
if (commonType != null) {
for (int i = 0, l = this.resultExpressions.size(); i < l; ++i) {
this.resultExpressions.get(i).computeConversion(this.scope, commonType, this.originalValueResultExpressionTypes[i]);
this.finalValueResultExpressionTypes[i] = commonType;
}
return this.resolvedType = commonType.capture(this.scope, this.sourceStart, this.sourceEnd);
}
this.scope.problemReporter().switchExpressionIncompatibleResultExpressions(this);
return null;
} finally {
if (this.scope != null) this.scope.enclosingCase = null; // no longer inside switch case block
}
}
/*
* pre-req: type.isNumeric() true
*/
private TypeBinding getFirstResults(TypeBinding type, Expression expr, TypeBinding resultNumeric) {
if (resultNumeric == null || TypeBinding.equalsEquals(type, resultNumeric))
return resultNumeric;
int[] typeId = new int[]{T_double, T_float, T_long};
for (int id : typeId) {
if (resultNumeric.id == id || type.id == id)
return TypeBinding.wellKnownType(this.scope, id);
}
if (type.id == T_int && expr.constant != Constant.NotAConstant)
return TypeBinding.INT;
return null;
}
private boolean isIntegerConvertible(TypeBinding targetType) {
if (TypeBinding.equalsEquals(targetType, TypeBinding.INT))
return true;
for (int i = 0, l = this.resultExpressions.size(); i < l; ++i) {
Expression e = this.resultExpressions.get(i);
TypeBinding t = this.originalValueResultExpressionTypes[i];
if (!TypeBinding.equalsEquals(t, TypeBinding.INT)) continue;
if (!e.isConstantValueOfTypeAssignableToType(t, targetType))
return false;
}
return true;
}
private TypeBinding getResultNumeric(HashSet<TypeBinding> typeSet, TypeBinding[] armTypes) {
if (typeSet.contains(TypeBinding.CHAR) && typeSet.contains(TypeBinding.SHORT)) {
return TypeBinding.INT;
}
TypeBinding[] types = new TypeBinding[] { TypeBinding.CHAR, TypeBinding.SHORT, TypeBinding.BYTE };
for (TypeBinding t : types) {
if (typeSet.contains(t) && isIntegerConvertible(t))
return t;
}
return TypeBinding.INT;
}
@Override
public boolean isPolyExpression() throws UnsupportedOperationException {
if (this.isPolyExpression)
return true;
return this.isPolyExpression = this.expressionContext == ASSIGNMENT_CONTEXT ||
this.expressionContext == INVOCATION_CONTEXT;
}
}
