com.google.devtools.build.lib.skyframe.PrepareDepsOfPatternsFunction.java Source code

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Here is the source code for com.google.devtools.build.lib.skyframe.PrepareDepsOfPatternsFunction.java

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// Copyright 2015 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.skyframe;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.cmdline.TargetParsingException;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.pkgcache.ParseFailureListener;
import com.google.devtools.build.lib.skyframe.PrepareDepsOfPatternValue.PrepareDepsOfPatternSkyKeyOrException;
import com.google.devtools.build.lib.skyframe.PrepareDepsOfPatternsValue.TargetPatternSequence;
import com.google.devtools.build.lib.skyframe.TargetPatternValue.TargetPatternKey;
import com.google.devtools.build.lib.util.Preconditions;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyKey;
import com.google.devtools.build.skyframe.SkyValue;
import com.google.devtools.build.skyframe.ValueOrException;

import java.util.Map;

import javax.annotation.Nullable;

/**
 * PrepareDepsOfPatternsFunction ensures the graph loads targets matching the pattern sequence and
 * their transitive dependencies.
 */
public class PrepareDepsOfPatternsFunction implements SkyFunction {

    public static ImmutableList<SkyKey> getSkyKeys(SkyKey skyKey, EventHandler eventHandler) {
        TargetPatternSequence targetPatternSequence = (TargetPatternSequence) skyKey.argument();
        Iterable<PrepareDepsOfPatternSkyKeyOrException> keysMaybe = PrepareDepsOfPatternValue
                .keys(targetPatternSequence.getPatterns(), targetPatternSequence.getOffset());

        ImmutableList.Builder<SkyKey> skyKeyBuilder = ImmutableList.builder();
        boolean handlerIsParseFailureListener = eventHandler instanceof ParseFailureListener;
        for (PrepareDepsOfPatternSkyKeyOrException skyKeyOrException : keysMaybe) {
            try {
                skyKeyBuilder.add(skyKeyOrException.getSkyKey());
            } catch (TargetParsingException e) {
                handleTargetParsingException(eventHandler, handlerIsParseFailureListener,
                        skyKeyOrException.getOriginalPattern(), e);
            }
        }

        return skyKeyBuilder.build();
    }

    private static final Function<SkyKey, TargetPatternKey> SKY_TO_TARGET_PATTERN = new Function<SkyKey, TargetPatternKey>() {
        @Nullable
        @Override
        public TargetPatternKey apply(SkyKey skyKey) {
            return (TargetPatternKey) skyKey.argument();
        }
    };

    public static ImmutableList<TargetPatternKey> getTargetPatternKeys(ImmutableList<SkyKey> skyKeys) {
        return ImmutableList.copyOf(Iterables.transform(skyKeys, SKY_TO_TARGET_PATTERN));
    }

    /**
     * Given a {@link SkyKey} that contains a sequence of target patterns, when this function returns
     * {@link PrepareDepsOfPatternsValue}, then all targets matching that sequence, and those targets'
     * transitive dependencies, have been loaded.
     */
    @Nullable
    @Override
    public SkyValue compute(SkyKey skyKey, Environment env) throws InterruptedException {
        EventHandler eventHandler = env.getListener();
        ImmutableList<SkyKey> skyKeys = getSkyKeys(skyKey, eventHandler);

        Map<SkyKey, ValueOrException<TargetParsingException>> tokensByKey = env.getValuesOrThrow(skyKeys,
                TargetParsingException.class);
        if (env.valuesMissing()) {
            return null;
        }

        boolean handlerIsParseFailureListener = eventHandler instanceof ParseFailureListener;
        for (SkyKey key : skyKeys) {
            try {
                // The only exception type throwable by PrepareDepsOfPatternFunction is
                // TargetParsingException. Therefore all ValueOrException values in the map will either
                // be non-null or throw TargetParsingException when get is called.
                Preconditions.checkNotNull(tokensByKey.get(key).get());
            } catch (TargetParsingException e) {
                // If a target pattern can't be evaluated, notify the user of the problem and keep going.
                handleTargetParsingException(eventHandler, handlerIsParseFailureListener, key, e);
            }
        }

        return new PrepareDepsOfPatternsValue(getTargetPatternKeys(skyKeys));
    }

    private static void handleTargetParsingException(EventHandler eventHandler,
            boolean handlerIsParseFailureListener, SkyKey key, TargetParsingException e) {
        TargetPatternKey patternKey = (TargetPatternKey) key.argument();
        String rawPattern = patternKey.getPattern();
        handleTargetParsingException(eventHandler, handlerIsParseFailureListener, rawPattern, e);
    }

    private static void handleTargetParsingException(EventHandler eventHandler,
            boolean handlerIsParseFailureListener, String rawPattern, TargetParsingException e) {
        String errorMessage = e.getMessage();
        eventHandler.handle(Event.error("Skipping '" + rawPattern + "': " + errorMessage));
        if (handlerIsParseFailureListener) {
            ParseFailureListener parseListener = (ParseFailureListener) eventHandler;
            parseListener.parsingError(rawPattern, errorMessage);
        }
    }

    @Nullable
    @Override
    public String extractTag(SkyKey skyKey) {
        return null;
    }

}