com.google.devtools.build.lib.rules.config.ConfigFeatureFlag.java Source code

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Here is the source code for com.google.devtools.build.lib.rules.config.ConfigFeatureFlag.java

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// Copyright 2017 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.rules.config;

import static com.google.devtools.build.lib.collect.nestedset.Order.STABLE_ORDER;
import static com.google.devtools.build.lib.syntax.Type.STRING;
import static com.google.devtools.build.lib.syntax.Type.STRING_LIST;

import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMultiset;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Multiset;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.RunfilesProvider;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.packages.RuleClass.ConfiguredTargetFactory.RuleErrorException;
import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
import com.google.devtools.build.lib.syntax.Printer;
import java.util.List;

/**
 * The implementation of the config_feature_flag rule for defining custom flags for Android rules.
 */
public class ConfigFeatureFlag implements RuleConfiguredTargetFactory {

    @Override
    public ConfiguredTarget create(RuleContext ruleContext) throws InterruptedException, RuleErrorException {
        List<String> specifiedValues = ruleContext.attributes().get("allowed_values", STRING_LIST);
        ImmutableSet<String> values = ImmutableSet.copyOf(specifiedValues);
        Predicate<String> isValidValue = Predicates.in(values);
        if (values.size() != specifiedValues.size()) {
            ImmutableMultiset<String> groupedValues = ImmutableMultiset.copyOf(specifiedValues);
            ImmutableList.Builder<String> duplicates = new ImmutableList.Builder<String>();
            for (Multiset.Entry<String> value : groupedValues.entrySet()) {
                if (value.getCount() > 1) {
                    duplicates.add(value.getElement());
                }
            }
            ruleContext.attributeError("allowed_values", "cannot contain duplicates, but contained multiple of "
                    + Printer.repr(duplicates.build(), '\''));
        }

        String defaultValue = ruleContext.attributes().get("default_value", STRING);
        if (!isValidValue.apply(defaultValue)) {
            ruleContext.attributeError("default_value", "must be one of " + Printer.repr(values.asList(), '\'')
                    + ", but was " + Printer.repr(defaultValue, '\''));
        }

        if (ruleContext.hasErrors()) {
            // Don't bother validating the value if the flag was already incorrectly specified without
            // looking at the value.
            return null;
        }

        String value = ruleContext.getFragment(ConfigFeatureFlagConfiguration.class)
                .getFeatureFlagValue(ruleContext.getOwner()).or(defaultValue);

        if (!isValidValue.apply(value)) {
            // TODO(mstaib): When configurationError is available, use that instead.
            ruleContext.ruleError("value must be one of " + Printer.repr(values.asList(), '\'') + ", but was "
                    + Printer.repr(value, '\''));
            return null;
        }

        ConfigFeatureFlagProvider provider = ConfigFeatureFlagProvider.create(value, isValidValue);

        return new RuleConfiguredTargetBuilder(ruleContext)
                .setFilesToBuild(NestedSetBuilder.<Artifact>emptySet(STABLE_ORDER))
                .addProvider(RunfilesProvider.class, RunfilesProvider.EMPTY)
                .addProvider(ConfigFeatureFlagProvider.class, provider).addNativeDeclaredProvider(provider).build();
    }
}