/*
* Copyright 2010-2015 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 org.jetbrains.kotlin.types;
import com.google.common.collect.LinkedHashMultimap;
import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor;
import java.util.List;
import java.util.Map;
public class SubstitutionUtils {
private SubstitutionUtils() {
}
/**
* Builds a context with all the supertypes' parameters substituted
*/
@NotNull
public static TypeSubstitutor buildDeepSubstitutor(@NotNull KotlinType type) {
Map<TypeConstructor, TypeProjection> substitution = Maps.newHashMap();
TypeSubstitutor typeSubstitutor = TypeSubstitutor.create(substitution);
// we use the mutability of the map here
fillInDeepSubstitutor(type, typeSubstitutor, substitution, null);
return typeSubstitutor;
}
/**
For each supertype of a given type, we map type parameters to type arguments.
For instance, we have the following class hierarchy:
trait Iterable<out T>
trait Collection<out E>: Iterable<E>
trait MyFooCollection<F>: Collection<Foo<F>>
For MyFooCollection<out CharSequence>, the following multimap will be returned:
T declared in Iterable -> Foo<out CharSequence>
E declared in Collection -> Foo<out CharSequence>
F declared in MyFooCollection -> out CharSequence
*/
@NotNull
public static Multimap<TypeParameterDescriptor, TypeProjection> buildDeepSubstitutionMultimap(@NotNull KotlinType type) {
Multimap<TypeParameterDescriptor, TypeProjection> fullSubstitution = LinkedHashMultimap.create();
Map<TypeConstructor, TypeProjection> substitution = Maps.newHashMap();
TypeSubstitutor typeSubstitutor = TypeSubstitutor.create(substitution);
// we use the mutability of the map here
fillInDeepSubstitutor(type, typeSubstitutor, substitution, fullSubstitution);
return fullSubstitution;
}
// we use the mutability of the substitution map here
private static void fillInDeepSubstitutor(
@NotNull KotlinType context,
@NotNull TypeSubstitutor substitutor,
@NotNull Map<TypeConstructor, TypeProjection> substitution,
@Nullable Multimap<TypeParameterDescriptor, TypeProjection> typeParameterMapping
) {
List<TypeParameterDescriptor> parameters = context.getConstructor().getParameters();
List<TypeProjection> arguments = context.getArguments();
if (parameters.size() != arguments.size()) {
throw new IllegalStateException();
}
for (int i = 0; i < arguments.size(); i++) {
TypeProjection argument = arguments.get(i);
TypeParameterDescriptor parameter = parameters.get(i);
TypeProjection substitute = substitutor.substitute(argument);
assert substitute != null;
substitution.put(parameter.getTypeConstructor(), substitute);
if (typeParameterMapping != null) {
typeParameterMapping.put(parameter, substitute);
}
}
if (KotlinBuiltIns.isNothingOrNullableNothing(context)) return;
for (KotlinType supertype : context.getConstructor().getSupertypes()) {
fillInDeepSubstitutor(supertype, substitutor, substitution, typeParameterMapping);
}
}
}