// 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.analysis;

import static com.google.devtools.build.lib.packages.Attribute.attr;
import static com.google.devtools.build.lib.packages.BuildType.LABEL_LIST;

import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.packages.RuleClass;

/** Helper class to manage rules' use of platforms. */
public class PlatformSemantics {

  public static final String TOOLCHAINS_ATTR = "$toolchains";

  public static RuleClass.Builder platformAttributes(RuleClass.Builder builder) {
    return builder
        .add(
            attr(TOOLCHAINS_ATTR, LABEL_LIST)
                .nonconfigurable("Used in toolchain resolution")
                .value(ImmutableList.of()));
  }
}