src/main/java/com/google/devtools/build/lib/pkgcache/PackageCacheOptions.java

// Copyright 2014 Google Inc. 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.devtools.build.lib.Constants;
import com.google.devtools.build.lib.packages.ConstantRuleVisibility;
import com.google.devtools.build.lib.packages.RuleVisibility;
import com.google.devtools.build.lib.syntax.CommaSeparatedPackageNameListConverter;
import com.google.devtools.common.options.Converter;
import com.google.devtools.common.options.Converters;
import com.google.devtools.common.options.Option;
import com.google.devtools.common.options.OptionsBase;
import com.google.devtools.common.options.OptionsParsingException;

import java.util.List;

/**
 * Options for configuring the PackageCache.
 */
public class PackageCacheOptions extends OptionsBase {
  /**
   * A converter for package path that defaults to {@code Constants.DEFAULT_PACKAGE_PATH} if the
   * option is not given.
   *
   * <p>Required because you cannot specify a non-constant value in annotation attributes.
   */
  public static class PackagePathConverter implements Converter<List<String>> {
    @Override
    public List<String> convert(String input) throws OptionsParsingException {
      return input.isEmpty()
          ? Constants.DEFAULT_PACKAGE_PATH
          : new Converters.ColonSeparatedOptionListConverter().convert(input);
    }

    @Override
    public String getTypeDescription() {
      return "a string";
    }
  }

  /**
   * Converter for the {@code --default_visibility} option.
   */
  public static class DefaultVisibilityConverter implements Converter<RuleVisibility> {
    @Override
    public RuleVisibility convert(String input) throws OptionsParsingException {
      if (input.equals("public")) {
        return ConstantRuleVisibility.PUBLIC;
      } else if (input.equals("private")) {
        return ConstantRuleVisibility.PRIVATE;
      } else {
        throw new OptionsParsingException("Not a valid default visibility: '" + input
            + "' (should be 'public' or 'private'");
      }
    }

    @Override
    public String getTypeDescription() {
      return "default visibility";
    }
  }

  @Option(name = "package_path",
          defaultValue = "",
          category = "package loading",
          converter = PackagePathConverter.class,
          help = "A colon-separated list of where to look for packages. "
          +  "Elements beginning with '%workspace%' are relative to the enclosing "
          +  "workspace. If omitted or empty, the default is the output of "
          +  "'blaze info default-package-path'.")
  public List<String> packagePath;

  @Option(name = "show_package_location",
          defaultValue = "false",
          category = "verbosity",
          deprecationWarning = "This flag is no longer supported and will go away soon.",
          help = "If enabled, causes Blaze to print the location on the --package_path "
          + "from which each package was loaded.")
  public boolean showPackageLocation;

  @Option(name = "show_loading_progress",
          defaultValue = "true",
          category = "verbosity",
          help = "If enabled, causes Blaze to print \"Loading package:\" messages.")
  public boolean showLoadingProgress;

  @Option(name = "deleted_packages",
          defaultValue = "",
          category = "package loading",
          converter = CommaSeparatedPackageNameListConverter.class,
          help = "A comma-separated list of names of packages which the "
          + "build system will consider non-existent, even if they are "
          + "visible somewhere on the package path."
          + "\n"
          + "Use this option when deleting a subpackage 'x/y' of an "
          + "existing package 'x'.  For example, after deleting x/y/BUILD "
          + "in your client, the build system may complain if it "
          + "encounters a label '//x:y/z' if that is still provided by another "
          + "package_path entry.  Specifying --deleted_packages x/y avoids this "
          + "problem.")
  public List<String> deletedPackages;

  @Option(name = "default_visibility",
      defaultValue = "private",
      category = "undocumented",
      converter = DefaultVisibilityConverter.class,
      help = "Default visibility for packages that don't set it explicitly ('public' or "
          + "'private').")
  public RuleVisibility defaultVisibility;

  @Option(name = "min_pkg_count_for_ct_node_eviction",
      defaultValue = "3700",
      // Why is the default value 3700? As of December 2013, a medium target loads about this many
      // packages, uses ~310MB RAM to only load [1] or ~990MB to load and analyze [2,3]. So we
      // can likely load and analyze this many packages without worrying about Blaze OOM'ing.
      //
      // If the total number of unique packages so far [4] is higher than the value of this flag,
      // then we evict CT nodes [5] from the Skyframe graph.
      //
      // [1] blaze -x build --nobuild --noanalyze //medium:target
      // [2] blaze -x build --nobuild //medium:target
      // [3] according to "blaze info used-heap-size"
      // [4] this means the number of unique packages loaded by builds, including the current one,
      //     since the last CT node eviction [5]
      // [5] "CT node eviction" means clearing those nodes from the Skyframe graph that correspond
      //     to ConfiguredTargets; this is done using SkyframeExecutor.resetConfiguredTargets
      category = "undocumented",
      help = "Threshold for number of loaded packages before skyframe-m1 cache eviction kicks in")
  public int minLoadedPkgCountForCtNodeEviction;
}