com.facebook.buck.rules.AbstractDependencyVisitors.java Source code

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Here is the source code for com.facebook.buck.rules.AbstractDependencyVisitors.java

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/*
 * Copyright 2013-present Facebook, Inc.
 *
 * 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.facebook.buck.rules;

import com.facebook.buck.graph.DefaultImmutableDirectedAcyclicGraph;
import com.facebook.buck.graph.ImmutableDirectedAcyclicGraph;
import com.facebook.buck.graph.MutableDirectedGraph;
import com.google.common.collect.ImmutableSet;

public class AbstractDependencyVisitors {
    private AbstractDependencyVisitors() {
    }

    /**
     * Given dependencies in inputs builds graph of transitive dependencies filtering them by
     * instanceOf T.
     *
     * @param inputs      initial dependencies from which to build transitive closure
     * @param typeFilter  class to filter with on instanceOf, we need this because of
     *                    the type erasure
     * @param <T>         class to fitler on
     * @return            filtered BuildRule DAG of transitive dependencies
     *
     * @see com.facebook.buck.rules.BuildRule
     */
    public static <T> ImmutableDirectedAcyclicGraph<BuildRule> getBuildRuleDirectedGraphFilteredBy(
            final Iterable<? extends BuildRule> inputs, final Class<T> typeFilter) {
        // Build up a graph of the inputs and their transitive dependencies, we'll use the graph
        // to topologically sort the dependencies.
        final MutableDirectedGraph<BuildRule> graph = new MutableDirectedGraph<>();
        AbstractDependencyVisitor visitor = new AbstractDependencyVisitor(inputs) {
            @Override
            public ImmutableSet<BuildRule> visit(BuildRule rule) {
                if (typeFilter.isAssignableFrom(rule.getClass())) {
                    graph.addNode(rule);
                    for (BuildRule dep : rule.getDeps()) {
                        if (typeFilter.isAssignableFrom(dep.getClass())) {
                            graph.addEdge(rule, dep);
                        }
                    }
                    return rule.getDeps();
                } else {
                    return ImmutableSet.of();
                }
            }
        };
        visitor.start();
        return new DefaultImmutableDirectedAcyclicGraph<BuildRule>(graph);
    }
}