001    /*
002     * Copyright 2010-2015 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.kotlin.types;
018    
019    import org.jetbrains.annotations.NotNull;
020    import org.jetbrains.annotations.Nullable;
021    import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
022    import org.jetbrains.kotlin.descriptors.ClassDescriptor;
023    import org.jetbrains.kotlin.descriptors.ClassifierDescriptor;
024    import org.jetbrains.kotlin.name.FqNameUnsafe;
025    import org.jetbrains.kotlin.resolve.DescriptorUtils;
026    import org.jetbrains.kotlin.resolve.descriptorUtil.DescriptorUtilsKt;
027    
028    public abstract class AbstractClassTypeConstructor implements TypeConstructor {
029        private boolean hashCodeComputed;
030        private int hashCode;
031    
032        @Override
033        public final int hashCode() {
034            if (!hashCodeComputed) {
035                hashCodeComputed = true;
036                hashCode = hashCode(this);
037            }
038            return hashCode;
039        }
040    
041        @NotNull
042        @Override
043        public abstract ClassifierDescriptor getDeclarationDescriptor();
044    
045        @NotNull
046        @Override
047        public KotlinBuiltIns getBuiltIns() {
048            return DescriptorUtilsKt.getBuiltIns(getDeclarationDescriptor());
049        }
050    
051        @Override
052        @SuppressWarnings("EqualsWhichDoesntCheckParameterClass")
053        public boolean equals(Object obj) {
054            return equals(this, obj);
055        }
056    
057        public static boolean equals(@NotNull TypeConstructor me, Object other) {
058            if (!(other instanceof TypeConstructor)) return false;
059    
060            // performance optimization: getFqName is slow method
061            if (other.hashCode() != me.hashCode()) return false;
062    
063            ClassifierDescriptor myDescriptor = me.getDeclarationDescriptor();
064            ClassifierDescriptor otherDescriptor = ((TypeConstructor) other).getDeclarationDescriptor();
065    
066            // descriptor for type is created once per module
067            if (myDescriptor == otherDescriptor) return true;
068    
069            // All error types have the same descriptor
070            if (myDescriptor != null && !hasMeaningfulFqName(myDescriptor) ||
071                otherDescriptor != null && !hasMeaningfulFqName(otherDescriptor)) {
072                return me == other;
073            }
074    
075            if (myDescriptor instanceof ClassDescriptor && otherDescriptor instanceof ClassDescriptor) {
076                FqNameUnsafe otherFqName = DescriptorUtils.getFqName(otherDescriptor);
077                FqNameUnsafe myFqName = DescriptorUtils.getFqName(myDescriptor);
078                return myFqName.equals(otherFqName);
079            }
080    
081            return false;
082        }
083    
084        public static int hashCode(@NotNull TypeConstructor me) {
085            ClassifierDescriptor descriptor = me.getDeclarationDescriptor();
086            if (descriptor instanceof ClassDescriptor && hasMeaningfulFqName(descriptor)) {
087                return DescriptorUtils.getFqName(descriptor).hashCode();
088            }
089            return System.identityHashCode(me);
090        }
091    
092        private static boolean hasMeaningfulFqName(@NotNull ClassifierDescriptor descriptor) {
093            return !ErrorUtils.isError(descriptor) &&
094                   !DescriptorUtils.isLocal(descriptor);
095        }
096    }