| // 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 java.util.ArrayList; |
| import java.util.List; |
| import javax.annotation.Nullable; |
| |
| /** |
| * A provider that wraps a transitive info provider map. |
| * |
| * <p>Useful for wrapping providers in aspects in a general way where there would otherwise be a |
| * conflict. |
| */ |
| public interface WrappingProvider extends TransitiveInfoProvider { |
| TransitiveInfoProviderMap getTransitiveInfoProviderMap(); |
| |
| /** |
| * Helper methods for {@link WrappingProvider}. |
| * |
| * <p>This class can be removed once Java 8 is supported and we can put static methods on |
| * interfaces. |
| */ |
| class Helper { |
| |
| /** Gets the actual providers from a list of wrappers. */ |
| public static <T extends TransitiveInfoProvider> List<T> unwrapProviders( |
| Iterable<? extends WrappingProvider> wrappingProviders, Class<T> providerClass) { |
| List<T> result = new ArrayList<>(); |
| for (WrappingProvider wrappingProvider : wrappingProviders) { |
| T provider = wrappingProvider.getTransitiveInfoProviderMap().getProvider(providerClass); |
| if (provider != null) { |
| result.add(provider); |
| } |
| } |
| return result; |
| } |
| |
| /** Reads a provider via a wrapping provider. Returns null if not wrapped. */ |
| @Nullable |
| public static <T extends TransitiveInfoProvider, U extends WrappingProvider> |
| T getWrappedProvider( |
| TransitiveInfoCollection collection, |
| Class<U> wrappingProviderClass, |
| Class<T> providerClass) { |
| WrappingProvider wrappingProvider = collection.getProvider(wrappingProviderClass); |
| if (wrappingProvider != null) { |
| return wrappingProvider.getTransitiveInfoProviderMap().getProvider(providerClass); |
| } |
| return null; |
| } |
| } |
| } |