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/*
* Copyright 2000-2013 JetBrains s.r.o.
*
* 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.intellij.psi.impl.source.resolve.graphInference;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.psi.*;
import com.intellij.psi.impl.source.resolve.graphInference.constraints.TypeEqualityConstraint;
import com.intellij.psi.util.TypeConversionUtil;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.Nullable;
import java.util.HashSet;
public class FunctionalInterfaceParameterizationUtil {
private static final Logger LOG = Logger.getInstance("#" + FunctionalInterfaceParameterizationUtil.class.getName());
public static boolean isWildcardParameterized(@Nullable PsiType classType) {
if (classType == null) return false;
if (classType instanceof PsiIntersectionType) {
for (PsiType type : ((PsiIntersectionType)classType).getConjuncts()) {
if (!isWildcardParameterized(type)) return false;
}
}
if (classType instanceof PsiClassType) {
for (PsiType type : ((PsiClassType)classType).getParameters()) {
if (type instanceof PsiWildcardType || type instanceof PsiCapturedWildcardType) {
return true;
}
}
return false;
}
return false;
}
@Nullable
public static PsiType getGroundTargetType(@Nullable PsiType psiClassType) {
return getGroundTargetType(psiClassType, null);
}
@Nullable
public static PsiType getGroundTargetType(@Nullable PsiType psiClassType, @Nullable PsiLambdaExpression expr) {
if (!isWildcardParameterized(psiClassType)) {
return psiClassType;
}
if (expr != null && expr.hasFormalParameterTypes()) return getFunctionalTypeExplicit(psiClassType, expr);
return psiClassType instanceof PsiClassType ? getNonWildcardParameterization((PsiClassType)psiClassType) : null;
}
private static PsiType getFunctionalTypeExplicit(PsiType psiClassType, PsiLambdaExpression expr) {
final PsiParameter[] lambdaParams = expr.getParameterList().getParameters();
if (psiClassType instanceof PsiIntersectionType) {
for (PsiType psiType : ((PsiIntersectionType)psiClassType).getConjuncts()) {
final PsiType functionalType = getFunctionalTypeExplicit(psiType, expr);
if (functionalType != null) return functionalType;
}
return null;
}
LOG.assertTrue(psiClassType instanceof PsiClassType, "Unexpected type: " + psiClassType);
final PsiType[] parameters = ((PsiClassType)psiClassType).getParameters();
final PsiClassType.ClassResolveResult resolveResult = ((PsiClassType)psiClassType).resolveGenerics();
PsiClass psiClass = resolveResult.getElement();
if (psiClass != null) {
final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(resolveResult);
if (interfaceMethod == null) return null;
PsiTypeParameter[] typeParameters = psiClass.getTypeParameters();
if (typeParameters.length != parameters.length) {
return null;
}
final PsiElementFactory elementFactory = JavaPsiFacade.getElementFactory(psiClass.getProject());
final PsiParameter[] targetMethodParams = interfaceMethod.getParameterList().getParameters();
if (targetMethodParams.length != lambdaParams.length) {
return null;
}
final InferenceSession session = new InferenceSession(typeParameters, PsiSubstitutor.EMPTY, expr.getManager(), expr);
for (int i = 0; i < targetMethodParams.length; i++) {
session.addConstraint(new TypeEqualityConstraint(lambdaParams[i].getType(), targetMethodParams[i].getType()));
}
if (!session.repeatInferencePhases(false)) {
return null;
}
final PsiSubstitutor substitutor = session.retrieveNonPrimitiveEqualsBounds(session.getInferenceVariables());
final PsiType[] newTypeParameters = new PsiType[parameters.length];
for (int i = 0; i < typeParameters.length; i++) {
PsiTypeParameter typeParameter = typeParameters[i];
if (substitutor.getSubstitutionMap().containsKey(typeParameter)) {
newTypeParameters[i] = substitutor.substitute(typeParameter);
} else {
newTypeParameters[i] = parameters[i];
}
}
final PsiClassType parameterization = elementFactory.createType(psiClass, newTypeParameters);
if (!isWellFormed(psiClass, typeParameters, newTypeParameters)) {
return null;
}
if (!TypeConversionUtil.containsWildcards(parameterization) && psiClassType.isAssignableFrom(parameterization)) {
return parameterization;
}
return getNonWildcardParameterization((PsiClassType)psiClassType);
}
return null;
}
private static boolean isWellFormed(PsiClass psiClass, PsiTypeParameter[] typeParameters, PsiType[] newTypeParameters) {
final PsiSubstitutor substitutor = PsiSubstitutor.EMPTY.putAll(psiClass, newTypeParameters);
for (int i = 0; i < typeParameters.length; i++) {
for (PsiClassType bound : typeParameters[i].getExtendsListTypes()) {
if (GenericsUtil.checkNotInBounds(newTypeParameters[i], substitutor.substitute(bound), false)) {
return false;
}
}
}
return true;
}
/**
The function type of a parameterized functional interface, F<A1...An>, where one or more of A1...An is a wildcard, is the function type of the non-wildcard parameterization of F, F<T1...Tn> determined as follows.
Let P1, ..., Pn be the type parameters of F and B1, ..., Bn be the corresponding bounds. For all i, 1 ≤ i ≤ n, Ti is derived according to the form of Ai:
If Ai is a type, then Ti = Ai.
If Ai is a wildcard, and the corresponding type parameter bound, Bi, mentions one of P1...Pn, then Ti is undefined and there is no function type.
Otherwise:
If Ai is an unbound wildcard ?, then Ti = Bi.
If Ai is a upper-bounded wildcard ? extends Ui, then Ti = glb(Ui, Bi).
If Ai is a lower-bounded wildcard ? super Li, then Ti = Li.
*/
@Nullable
public static PsiType getNonWildcardParameterization(PsiClassType psiClassType) {
final PsiClass psiClass = psiClassType.resolve();
if (psiClass != null) {
final PsiTypeParameter[] typeParameters = psiClass.getTypeParameters();
final PsiType[] parameters = psiClassType.getParameters();
final PsiType[] newParameters = new PsiType[parameters.length];
if (parameters.length != typeParameters.length) return null;
final HashSet<PsiTypeParameter> typeParametersSet = ContainerUtil.newHashSet(typeParameters);
for (int i = 0; i < parameters.length; i++) {
PsiType paramType = parameters[i];
if (paramType instanceof PsiWildcardType) {
final PsiType bound = GenericsUtil.eliminateWildcards(((PsiWildcardType)paramType).getBound(), false);
if (((PsiWildcardType)paramType).isSuper()) {
newParameters[i] = bound;
}
else {
newParameters[i] = bound != null ? bound : PsiType.getJavaLangObject(psiClass.getManager(), psiClassType.getResolveScope());
for (PsiClassType paramBound : typeParameters[i].getExtendsListTypes()) {
if (!PsiPolyExpressionUtil.mentionsTypeParameters(paramBound, typeParametersSet)) {
newParameters[i] = GenericsUtil.getGreatestLowerBound(paramBound, newParameters[i]);
}
}
}
} else {
newParameters[i] = paramType;
}
}
if (!isWellFormed(psiClass, typeParameters, newParameters)) {
return null;
}
final PsiClassType parameterization = JavaPsiFacade.getElementFactory(psiClass.getProject()).createType(psiClass, newParameters);
if (!psiClassType.isAssignableFrom(parameterization)) {
return null;
}
return parameterization;
}
return null;
}
}
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