// 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.pkgcache;

import com.google.common.annotations.VisibleForTesting;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.concurrent.Uninterruptibles;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.packages.NoSuchPackageException;
import com.google.devtools.build.lib.packages.NoSuchTargetException;
import com.google.devtools.build.lib.packages.Target;

import java.util.concurrent.Callable;

/**
 * A bridge class that implements the legacy semantics of {@link #getLoadedTarget} using a normal
 * {@link PackageProvider} instance.
 *
 * <p>DO NOT USE! It will be removed when the transition to Skyframe is complete.
 */
public final class LoadedPackageProvider {
  private final PackageProvider packageProvider;
  private final EventHandler eventHandler;

  public LoadedPackageProvider(PackageProvider packageProvider, EventHandler eventHandler) {
    this.packageProvider = packageProvider;
    this.eventHandler = eventHandler;
  }

  public EventHandler getEventHandler() {
    return eventHandler;
  }

  /**
   * Returns a target if it was recently loaded, i.e., since the most recent cache sync. This
   * throws an exception if the target was not loaded or not validated, even if it exists in the
   * surrounding package. If the surrounding package is in error, still attempts to retrieve the
   * target.
   */
  public Target getLoadedTarget(Label label) throws NoSuchPackageException, NoSuchTargetException {
    return getLoadedTarget(packageProvider, eventHandler, label);
  }

  /**
   * Uninterruptible method to convert a label into a target using a given package provider and
   * event handler.
   */
  @VisibleForTesting
  public static Target getLoadedTarget(
      final PackageProvider packageProvider, final EventHandler eventHandler, final Label label)
          throws NoSuchPackageException, NoSuchTargetException {
    try {
      return Uninterruptibles.callUninterruptibly(new Callable<Target>() {
        @Override
        public Target call()
            throws NoSuchPackageException, NoSuchTargetException, InterruptedException {
          return packageProvider.getTarget(eventHandler, label);
        }
      });
    } catch (NoSuchPackageException | NoSuchTargetException e) {
      throw e;
    } catch (Exception e) {
      throw new IllegalStateException(e);
    }
  }
}