russell@unturf.com
0a580b313d
Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com Patches, unit tests, benchmarks, whitepaper, and outreach briefs. Public domain — no copyright claimed. Use freely.
53 lines
2.5 KiB
Java
53 lines
2.5 KiB
Java
package net.minecraft.util;
|
|
|
|
import com.google.common.collect.HashMultimap;
|
|
import com.google.common.collect.Multimap;
|
|
import java.util.Collection;
|
|
import java.util.HashMap;
|
|
import java.util.HashSet;
|
|
import java.util.Map;
|
|
import java.util.Set;
|
|
import java.util.function.BiConsumer;
|
|
import java.util.function.Consumer;
|
|
|
|
/** AFTER — fixed: isCyclic passes visited set — O(E) per call, O(E²) total */
|
|
public class DependencySorter<K, V extends DependencySorter.Entry<K>> {
|
|
private final Map<K, V> contents = new HashMap<>();
|
|
|
|
public DependencySorter<K, V> addEntry(K id, V value) {
|
|
this.contents.put(id, value);
|
|
return this;
|
|
}
|
|
|
|
private void visitDependenciesAndElement(Multimap<K, K> dependencies, Set<K> alreadyVisited, K id, BiConsumer<K, V> output) {
|
|
if (!alreadyVisited.add(id)) return;
|
|
dependencies.get(id).forEach(dep -> visitDependenciesAndElement(dependencies, alreadyVisited, dep, output));
|
|
V current = this.contents.get(id);
|
|
if (current != null) output.accept(id, current);
|
|
}
|
|
|
|
// FIX: visited set prevents exponential revisiting of diamond nodes
|
|
private static <K> boolean isCyclic(Multimap<K, K> directDependencies, K from, K to, Set<K> visited) {
|
|
if (!visited.add(to)) return false; // already explored — no cycle via here
|
|
Collection<K> dependencies = directDependencies.get(to);
|
|
if (dependencies.contains(from)) return true;
|
|
return dependencies.stream().anyMatch(dep -> isCyclic(directDependencies, from, dep, visited));
|
|
}
|
|
|
|
private static <K> void addDependencyIfNotCyclic(Multimap<K, K> directDependencies, K from, K to) {
|
|
if (!isCyclic(directDependencies, from, to, new HashSet<>())) directDependencies.put(from, to);
|
|
}
|
|
|
|
public void orderByDependencies(BiConsumer<K, V> output) {
|
|
HashMultimap<K, K> directDependencies = HashMultimap.create();
|
|
this.contents.forEach((id, value) -> value.visitRequiredDependencies(dep -> addDependencyIfNotCyclic(directDependencies, id, dep)));
|
|
this.contents.forEach((id, value) -> value.visitOptionalDependencies(dep -> addDependencyIfNotCyclic(directDependencies, id, dep)));
|
|
Set<K> alreadyVisited = new HashSet<>();
|
|
this.contents.keySet().forEach(id -> visitDependenciesAndElement(directDependencies, alreadyVisited, id, output));
|
|
}
|
|
|
|
public interface Entry<K> {
|
|
void visitRequiredDependencies(Consumer<K> consumer);
|
|
void visitOptionalDependencies(Consumer<K> consumer);
|
|
}
|
|
}
|