// Copyright 2018 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.standalone;

import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.actions.Action;
import com.google.devtools.build.lib.actions.ActionContext;
import com.google.devtools.build.lib.actions.ActionExecutionContext;
import com.google.devtools.build.lib.actions.ActionExecutionException;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.ArtifactResolver;
import com.google.devtools.build.lib.actions.ExecException;
import com.google.devtools.build.lib.actions.ExecutionStrategy;
import com.google.devtools.build.lib.exec.ActionContextProvider;
import com.google.devtools.build.lib.rules.cpp.CppCompileAction;
import com.google.devtools.build.lib.rules.cpp.CppIncludeExtractionContext;
import com.google.devtools.build.lib.rules.cpp.CppIncludeScanningContext;
import com.google.devtools.build.lib.rules.cpp.IncludeProcessing;
import com.google.devtools.build.lib.runtime.CommandEnvironment;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import java.io.IOException;
import javax.annotation.Nullable;

/**
 * Provide a standalone, local execution context.
 */
public class DummyIncludeScanningContextProvider extends ActionContextProvider {

  /**
   * An IncludeExtractionContext that does nothing. Since local execution does not need to discover
   * inclusion in advance, we do not need include scanning.
   */
  @ExecutionStrategy(contextType = CppIncludeExtractionContext.class)
  class DummyCppIncludeExtractionContext implements CppIncludeExtractionContext {
    @Override
    public void extractIncludes(
        ActionExecutionContext actionExecutionContext,
        Action resourceOwner,
        Artifact primaryInput,
        Artifact primaryOutput,
        Artifact grepIncludes)
        throws IOException {
      FileSystemUtils.writeContent(
          actionExecutionContext.getInputPath(primaryOutput), new byte[] {});
    }

    @Override
    public ArtifactResolver getArtifactResolver() {
      return env.getSkyframeBuildView().getArtifactFactory();
    }
  }

  /** A CppIncludeScanningContext that does nothing. */
  @ExecutionStrategy(contextType = CppIncludeScanningContext.class)
  static class DummyCppIncludeScanningContext implements CppIncludeScanningContext {
    @Override
    @Nullable
    public Iterable<Artifact> findAdditionalInputs(
        CppCompileAction action,
        ActionExecutionContext actionExecutionContext,
        IncludeProcessing includeProcessing)
        throws ExecException, InterruptedException, ActionExecutionException {
      return null;
    }
  }

  private final CommandEnvironment env;

  public DummyIncludeScanningContextProvider(CommandEnvironment env) {
    this.env = env;
  }

  @Override
  public Iterable<? extends ActionContext> getActionContexts() {
    return ImmutableList.of(
        new DummyCppIncludeExtractionContext(),
        new DummyCppIncludeScanningContext());
  }
}