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// Copyright 2018 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.analysis.config;
import static com.google.common.base.Predicates.not;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Interner;
import com.google.common.collect.Sets;
import com.google.devtools.build.lib.concurrent.BlazeInterners;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.SerializationConstant;
import com.google.devtools.build.lib.util.ClassName;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import javax.annotation.concurrent.Immutable;
/**
* A wrapper class for an {@code ImmutableSortedSet<Class<? extends Fragment>>}. Interning these
* objects allows us to do cheap reference equality checks when these sets are in frequently used
* keys.
*/
@Immutable
public final class FragmentClassSet extends AbstractSet<Class<? extends Fragment>> {
/**
* Sorts fragments by class name. This produces a stable order which, e.g., facilitates consistent
* output from buildMnemonic.
*/
@SerializationConstant
public static final Comparator<Class<? extends Fragment>> LEXICAL_FRAGMENT_SORTER =
Comparator.comparing(Class::getName);
private static final Interner<FragmentClassSet> interner = BlazeInterners.newWeakInterner();
public static FragmentClassSet of(Collection<Class<? extends Fragment>> fragments) {
ImmutableSortedSet<Class<? extends Fragment>> sortedFragments =
ImmutableSortedSet.copyOf(LEXICAL_FRAGMENT_SORTER, fragments);
return interner.intern(new FragmentClassSet(sortedFragments, sortedFragments.hashCode()));
}
private final ImmutableSortedSet<Class<? extends Fragment>> fragments;
private final int hashCode;
private FragmentClassSet(ImmutableSortedSet<Class<? extends Fragment>> fragments, int hashCode) {
this.fragments = fragments;
this.hashCode = hashCode;
}
@Override
public int size() {
return fragments.size();
}
@Override
public boolean contains(Object o) {
return fragments.contains(o);
}
/** Returns a set of fragment classes identical to this one but without the given fragment. */
public FragmentClassSet trim(Class<? extends Fragment> fragment) {
if (!contains(fragment)) {
return this;
}
return of(Sets.filter(fragments, not(fragment::equals)));
}
@Override
public Iterator<Class<? extends Fragment>> iterator() {
return fragments.iterator();
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof FragmentClassSet)) {
return false;
}
FragmentClassSet that = (FragmentClassSet) other;
return hashCode == that.hashCode && fragments.equals(that.fragments);
}
@Override
public int hashCode() {
return hashCode;
}
@Override
public String toString() {
return Collections2.transform(fragments, ClassName::getSimpleNameWithOuter).toString();
}
}