com.google.devtools.build.lib.syntax.SelectorValue.java Source code

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Here is the source code for com.google.devtools.build.lib.syntax.SelectorValue.java

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// Copyright 2014 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.syntax;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
import com.google.devtools.build.lib.syntax.SkylarkList.Tuple;

import java.util.Map;
import java.util.TreeMap;

/**
 * The value passed to a select({...}) statement, e.g.:
 *
 * <pre>
 *   rule(
 *       name = 'myrule',
 *       deps = select({
 *           'a': [':adep'],
 *           'b': [':bdep'],
 *       })
 * </pre>
 */
@SkylarkModule(name = "selector", doc = "A selector between configuration-dependent entities.", documented = false)
public final class SelectorValue implements SkylarkValue {
    // TODO(bazel-team): Selectors are currently split between .packages and .syntax . They should
    // really all be in .packages, but then we'd need to figure out a way how to extend binary
    // operators, which is a non-trivial problem.
    private final ImmutableMap<?, ?> dictionary;
    private final Class<?> type;
    private final String noMatchError;

    public SelectorValue(Map<?, ?> dictionary, String noMatchError) {
        // Put the dict through a sorting to avoid depending on insertion order.
        this.dictionary = ImmutableMap.copyOf(new TreeMap<>(dictionary));
        this.type = dictionary.isEmpty() ? Object.class : Iterables.get(dictionary.values(), 0).getClass();
        this.noMatchError = noMatchError;
    }

    /**
     * Returns an {@link ImmutableMap} containing the entries in the map provided to {@link
     * #SelectorValue} in sorted order.
     */
    public ImmutableMap<?, ?> getDictionary() {
        return dictionary;
    }

    Class<?> getType() {
        return type;
    }

    /**
     * Returns a custom error message for this select when no condition matches, or an empty
     * string if no such message is declared.
     */
    public String getNoMatchError() {
        return noMatchError;
    }

    @Override
    public String toString() {
        return Printer.repr(this);
    }

    @Override
    public void write(Appendable buffer, char quotationMark) {
        Printer.formatTo(buffer, "selector(%r)", Tuple.of(dictionary));
    }

    @Override
    public boolean isImmutable() {
        return false;
    }
}