com.facebook.buck.apple.xcode.RuleDependencyFinder.java Source code

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Here is the source code for com.facebook.buck.apple.xcode.RuleDependencyFinder.java

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/*
 * Copyright 2012-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.apple.xcode;

import com.facebook.buck.apple.IosTest;
import com.facebook.buck.apple.IosTestDescription;
import com.facebook.buck.graph.AbstractAcyclicDepthFirstPostOrderTraversal;
import com.facebook.buck.model.BuildTarget;
import com.facebook.buck.parser.PartialGraph;
import com.facebook.buck.rules.BuildRule;
import com.facebook.buck.util.HumanReadableException;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.ImmutableSet;

import java.io.IOException;
import java.util.Iterator;

/**
 * Utility class for discovering related rules when generating amalgamated xcode projects.
 */
final class RuleDependencyFinder {

    /**
     * Utility class should not be instantiated.
     */
    private RuleDependencyFinder() {
    }

    /**
     * Retrieve all rules related to the given roots in the given graph.
     *
     * "Related" is defined as:
     * - The rules themselves
     * - Their transitive dependencies
     * - The tests of the above rules
     * - Any additional dependencies of the tests
     */
    public static ImmutableSet<BuildRule> getAllRules(PartialGraph graph, Iterable<BuildTarget> initialTargets) {

        ImmutableList.Builder<BuildRule> initialRulesBuilder = ImmutableList.builder();
        for (BuildTarget target : initialTargets) {
            initialRulesBuilder.add(graph.getDependencyGraph().findBuildRuleByTarget(target));
        }

        ImmutableSet<BuildRule> buildRules = gatherTransitiveDependencies(initialRulesBuilder.build());
        ImmutableMultimap<BuildRule, BuildRule> ruleToTestRules = buildRuleToTestRulesMap(graph);

        // Extract the test rules for the initial rules and their dependencies.
        ImmutableSet.Builder<BuildRule> testRulesBuilder = ImmutableSet.builder();
        for (BuildRule rule : buildRules) {
            testRulesBuilder.addAll(ruleToTestRules.get(rule));
        }
        ImmutableSet<BuildRule> additionalBuildRules = gatherTransitiveDependencies(testRulesBuilder.build());

        return ImmutableSet.<BuildRule>builder().addAll(buildRules).addAll(additionalBuildRules).build();
    }

    private static ImmutableSet<BuildRule> gatherTransitiveDependencies(Iterable<? extends BuildRule> initial) {
        final ImmutableSet.Builder<BuildRule> buildRulesBuilder = ImmutableSet.builder();
        AbstractAcyclicDepthFirstPostOrderTraversal<BuildRule> allDependenciesTraversal = new AbstractAcyclicDepthFirstPostOrderTraversal<BuildRule>() {
            @Override
            protected Iterator<BuildRule> findChildren(BuildRule node) throws IOException {
                return node.getDeps().iterator();
            }

            @Override
            protected void onNodeExplored(BuildRule node) {
            }

            @Override
            protected void onTraversalComplete(Iterable<BuildRule> nodesInExplorationOrder) {
                buildRulesBuilder.addAll(nodesInExplorationOrder);
            }
        };
        try {
            allDependenciesTraversal.traverse(initial);
        } catch (AbstractAcyclicDepthFirstPostOrderTraversal.CycleException e) {
            throw new HumanReadableException(e,
                    "Cycle detected while gathering build rule dependencies for project generation:\n "
                            + e.getMessage());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return buildRulesBuilder.build();
    }

    /**
     * Create a map from targets to the tests that test them by examining
     * {@link com.facebook.buck.apple.IosTest#getSourceUnderTest()}.
     */
    private static ImmutableMultimap<BuildRule, BuildRule> buildRuleToTestRulesMap(PartialGraph graph) {
        ImmutableMultimap.Builder<BuildRule, BuildRule> ruleToTestRulesBuilder = ImmutableMultimap.builder();
        for (BuildTarget target : graph.getTargets()) {
            BuildRule rule = graph.getDependencyGraph().findBuildRuleByTarget(target);
            if (rule.getType().equals(IosTestDescription.TYPE)) {
                IosTest testBuildable = (IosTest) Preconditions.checkNotNull(rule.getBuildable());
                for (BuildRule sourceRule : testBuildable.getSourceUnderTest()) {
                    ruleToTestRulesBuilder.put(sourceRule, rule);
                }
            }
        }
        return ruleToTestRulesBuilder.build();
    }
}