src/main/java/com/google/devtools/build/lib/skyframe/AspectValue.java

// 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.skyframe;

import com.google.common.base.Objects;
import com.google.devtools.build.lib.actions.Action;
import com.google.devtools.build.lib.analysis.ConfiguredAspect;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.packages.Aspect;
import com.google.devtools.build.lib.packages.AspectClass;
import com.google.devtools.build.lib.packages.AspectParameters;
import com.google.devtools.build.lib.packages.Package;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.skyframe.SkyFunctionName;
import com.google.devtools.build.skyframe.SkyKey;

import javax.annotation.Nullable;

/**
 * An aspect in the context of the Skyframe graph.
 */
public final class AspectValue extends ActionLookupValue {

  /**
   * A base class for keys that have AspectValue as a Sky value.
   */
  public abstract static class AspectValueKey extends ActionLookupKey {

    public abstract String getDescription();
  }

  /**
   * A base class for a key representing an aspect applied to a particular target.
   */
  public static final class AspectKey extends AspectValueKey {
    private final Label label;
    private final BuildConfiguration aspectConfiguration;
    private final BuildConfiguration baseConfiguration;
    private final Aspect aspect;

    protected AspectKey(
        Label label,
        BuildConfiguration aspectConfiguration,
        BuildConfiguration baseConfiguration,
        AspectClass aspectClass,
        AspectParameters parameters) {
      this.label = label;
      this.aspectConfiguration = aspectConfiguration;
      this.baseConfiguration = baseConfiguration;
      this.aspect = new Aspect(aspectClass, parameters);
    }

    @Override
    SkyFunctionName getType() {
      return SkyFunctions.ASPECT;
    }


    @Override
    public Label getLabel() {
      return label;
    }

    public AspectClass getAspectClass() {
      return aspect.getAspectClass();
    }

    @Nullable
    public AspectParameters getParameters() {
      return aspect.getParameters();
    }

    public Aspect getAspect() {
      return aspect;
    }

    @Override
    public String getDescription() {
      return String.format("%s of %s", aspect.getAspectClass().getName(), getLabel());
    }

    /**
     * Returns the configuration to be used for the evaluation of the aspect itself.
     *
     * <p>In dynamic configuration mode, the aspect may require more fragments than the target on
     * which it is being evaluated; in addition to configuration fragments required by the target
     * and its dependencies, an aspect has configuration fragment requirements of its own, as well
     * as dependencies of its own with their own configuration fragment requirements.
     *
     * <p>The aspect configuration contains all of these fragments, and is used to create the
     * aspect's RuleContext and to retrieve the dependencies. Note that dependencies will have their
     * configurations trimmed from this one as normal.
     *
     * <p>Because of these properties, this configuration is always a superset of that returned by
     * {@link #getBaseConfiguration()}. In static configuration mode, this configuration will be
     * equivalent to that returned by {@link #getBaseConfiguration()}.
     *
     * @see #getBaseConfiguration()
     */
    public BuildConfiguration getAspectConfiguration() {
      return aspectConfiguration;
    }

    /**
     * Returns the configuration to be used for the base target.
     *
     * <p>In dynamic configuration mode, the configured target this aspect is attached to may have
     * a different configuration than the aspect itself (see the documentation for
     * {@link #getAspectConfiguration()} for an explanation why). The base configuration is the one
     * used to construct a key to look up the base configured target.
     *
     * @see #getAspectConfiguration()
     */
    public BuildConfiguration getBaseConfiguration() {
      return baseConfiguration;
    }

    @Override
    public int hashCode() {
      return Objects.hashCode(label, aspectConfiguration, baseConfiguration, aspect);
    }

    @Override
    public boolean equals(Object other) {
      if (this == other) {
        return true;
      }

      if (!(other instanceof AspectKey)) {
        return false;
      }

      AspectKey that = (AspectKey) other;
      return Objects.equal(label, that.label)
          && Objects.equal(aspectConfiguration, that.aspectConfiguration)
          && Objects.equal(baseConfiguration, that.baseConfiguration)
          && Objects.equal(aspect, that.aspect);
    }

    @Override
    public String toString() {
      return label
          + "#"
          + aspect.getAspectClass().getName()
          + " "
          + (aspectConfiguration == null ? "null" : aspectConfiguration.checksum())
          + " "
          + (baseConfiguration == null ? "null" : baseConfiguration.checksum())
          + " "
          + aspect.getParameters();
    }
  }

  /**
   * The key for a skylark aspect.
   */
  public static class SkylarkAspectLoadingKey extends AspectValueKey {

    private final Label targetLabel;
    private final BuildConfiguration aspectConfiguration;
    private final BuildConfiguration targetConfiguration;
    private final PathFragment extensionFile;
    private final String skylarkValueName;

    private SkylarkAspectLoadingKey(
        Label targetLabel,
        BuildConfiguration aspectConfiguration,
        BuildConfiguration targetConfiguration,
        PathFragment extensionFile,
        String skylarkFunctionName) {
      this.targetLabel = targetLabel;
      this.aspectConfiguration = aspectConfiguration;
      this.targetConfiguration = targetConfiguration;

      this.extensionFile = extensionFile;
      this.skylarkValueName = skylarkFunctionName;
    }

    @Override
    SkyFunctionName getType() {
      return SkyFunctions.LOAD_SKYLARK_ASPECT;
    }

    public PathFragment getExtensionFile() {
      return extensionFile;
    }

    public String getSkylarkValueName() {
      return skylarkValueName;
    }

    public Label getTargetLabel() {
      return targetLabel;
    }

    /**
     * @see AspectKey#getAspectConfiguration()
     */
    public BuildConfiguration getAspectConfiguration() {
      return aspectConfiguration;
    }

    /**
     * @see AspectKey#getBaseConfiguration()
     */
    public BuildConfiguration getTargetConfiguration() {
      return targetConfiguration;
    }

    @Override
    public String getDescription() {
      // Skylark aspects are referred to on command line with <file>%<value ame>
      return String.format("%s%%%s of %s", extensionFile.toString(), skylarkValueName, targetLabel);
    }
  }


  private final Label label;
  private final Location location;
  private final AspectKey key;
  private final ConfiguredAspect configuredAspect;
  private final NestedSet<Package> transitivePackages;

  public AspectValue(
      AspectKey key,
      Label label,
      Location location,
      ConfiguredAspect configuredAspect,
      Iterable<Action> actions,
      NestedSet<Package> transitivePackages) {
    super(actions);
    this.location = location;
    this.label = label;
    this.key = key;
    this.configuredAspect = configuredAspect;
    this.transitivePackages = transitivePackages;
  }

  public ConfiguredAspect getConfiguredAspect() {
    return configuredAspect;
  }

  public Label getLabel() {
    return label;
  }

  public Location getLocation() {
    return location;
  }

  public AspectKey getKey() {
    return key;
  }

  public NestedSet<Package> getTransitivePackages() {
    return transitivePackages;
  }

  /**
   * Constructs a new SkyKey containing an AspectKey.
   */
  public static SkyKey key(
      Label label,
      BuildConfiguration aspectConfiguration,
      BuildConfiguration baseConfiguration,
      AspectClass aspectFactory,
      AspectParameters additionalConfiguration) {
    return SkyKey.create(
        SkyFunctions.ASPECT,
        new AspectKey(
            label, aspectConfiguration, baseConfiguration, aspectFactory, additionalConfiguration));
  }

  public static SkyKey key(AspectValueKey aspectKey) {
    return SkyKey.create(aspectKey.getType(), aspectKey);
  }

  public static AspectKey createAspectKey(
      Label label,
      BuildConfiguration aspectConfiguration,
      BuildConfiguration baseConfiguration,
      AspectClass aspectFactory) {
    return new AspectKey(
        label, aspectConfiguration, baseConfiguration, aspectFactory, AspectParameters.EMPTY);
  }

  public static SkylarkAspectLoadingKey createSkylarkAspectKey(
      Label targetLabel,
      BuildConfiguration aspectConfiguration,
      BuildConfiguration targetConfiguration,
      PathFragment skylarkFile,
      String skylarkExportName) {
    return new SkylarkAspectLoadingKey(
        targetLabel, aspectConfiguration, targetConfiguration, skylarkFile, skylarkExportName);
  }
}