/*
* Copyright 2015 the original author or authors.
*
* 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.gradle.api.internal.artifacts.ivyservice.resolveengine.graph;
import org.gradle.api.artifacts.component.ComponentIdentifier;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class DependencyGraphPathResolver {
public static Collection<List<ComponentIdentifier>> calculatePaths(List<DependencyGraphNode> fromNodes, DependencyGraphNode toNode) {
// Include the shortest path from each version that has a direct dependency on the broken dependency, back to the root
Map<ComponentResult, List<ComponentIdentifier>> shortestPaths = new LinkedHashMap<ComponentResult, List<ComponentIdentifier>>();
List<ComponentIdentifier> rootPath = new ArrayList<ComponentIdentifier>();
rootPath.add(toNode.getOwner().getComponentId());
shortestPaths.put(toNode.getOwner(), rootPath);
Set<DependencyGraphComponent> directDependees = new LinkedHashSet<DependencyGraphComponent>();
for (DependencyGraphNode node : fromNodes) {
directDependees.add(node.getOwner());
}
Set<DependencyGraphComponent> seen = new HashSet<DependencyGraphComponent>();
LinkedList<DependencyGraphComponent> queue = new LinkedList<DependencyGraphComponent>();
queue.addAll(directDependees);
while (!queue.isEmpty()) {
DependencyGraphComponent version = queue.getFirst();
if (version == toNode.getOwner()) {
queue.removeFirst();
} else if (seen.add(version)) {
for (DependencyGraphComponent incomingVersion : version.getDependents()) {
queue.add(0, incomingVersion);
}
} else {
queue.remove();
List<ComponentIdentifier> shortest = null;
for (DependencyGraphComponent incomingVersion : version.getDependents()) {
List<ComponentIdentifier> candidate = shortestPaths.get(incomingVersion);
if (candidate == null) {
continue;
}
if (shortest == null) {
shortest = candidate;
} else if (shortest.size() > candidate.size()) {
shortest = candidate;
}
}
if (shortest == null) {
continue;
}
List<ComponentIdentifier> path = new ArrayList<ComponentIdentifier>();
path.addAll(shortest);
path.add(version.getComponentId());
shortestPaths.put(version, path);
}
}
List<List<ComponentIdentifier>> paths = new ArrayList<List<ComponentIdentifier>>();
for (DependencyGraphComponent version : directDependees) {
List<ComponentIdentifier> path = shortestPaths.get(version);
paths.add(path);
}
return paths;
}
}