// 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.actions;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue.RunfileSymlinksMode;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.collect.nestedset.Order;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.SerializationConstant;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.util.Map;
import javax.annotation.Nullable;

/** Empty implementation of RunfilesSupplier */
public final class EmptyRunfilesSupplier implements RunfilesSupplier {

  @SerializationConstant
  public static final EmptyRunfilesSupplier INSTANCE = new EmptyRunfilesSupplier();

  private EmptyRunfilesSupplier() {}

  @Override
  public NestedSet<Artifact> getArtifacts() {
    return NestedSetBuilder.emptySet(Order.STABLE_ORDER);
  }

  @Override
  public ImmutableSet<PathFragment> getRunfilesDirs() {
    return ImmutableSet.of();
  }

  @Override
  public ImmutableMap<PathFragment, Map<PathFragment, Artifact>> getMappings() {
    return ImmutableMap.of();
  }

  @Override
  @Nullable
  public RunfileSymlinksMode getRunfileSymlinksMode(PathFragment runfilesDir) {
    return null;
  }

  @Override
  public boolean isBuildRunfileLinks(PathFragment runfilesDir) {
    return false;
  }

  @Override
  public RunfilesSupplier withOverriddenRunfilesDir(PathFragment newRunfilesDir) {
    throw new UnsupportedOperationException();
  }
}
