src/main/java/com/google/devtools/build/lib/analysis/Util.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.analysis;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
import com.google.devtools.build.lib.analysis.config.CommonOptions;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.collect.compacthashset.CompactHashSet;
import com.google.devtools.build.lib.packages.AttributeMap;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetAndData;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetKey;
import com.google.devtools.build.lib.skyframe.config.BuildConfigurationKey;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.util.List;
import java.util.Set;

/** Utility methods for use by ConfiguredTarget implementations. */
public abstract class Util {

  private Util() {}

  // ---------- Label and Target related methods

  /**
   * Returns the workspace-relative path of the specified target (file or rule).
   *
   * <p>For example, "//foo/bar:wiz" and "//foo:bar/wiz" both result in "foo/bar/wiz".
   */
  public static PathFragment getWorkspaceRelativePath(Target target) {
    return getWorkspaceRelativePath(target.getLabel());
  }

  /**
   * Returns the workspace-relative path of the specified target (file or rule).
   *
   * <p>For example, "//foo/bar:wiz" and "//foo:bar/wiz" both result in "foo/bar/wiz".
   */
  public static PathFragment getWorkspaceRelativePath(Label label) {
    return label.getPackageFragment().getRelative(label.getName());
  }

  /**
   * Returns the workspace-relative path of the specified target (file or rule), prepending a prefix
   * and appending a suffix.
   *
   * <p>For example, "//foo/bar:wiz" and "//foo:bar/wiz" both result in "foo/bar/wiz".
   */
  public static PathFragment getWorkspaceRelativePath(Target target, String prefix, String suffix) {
    return target.getLabel().getPackageFragment().getRelative(prefix + target.getName() + suffix);
  }

  /** Checks if a PathFragment contains a '-'. */
  public static boolean containsHyphen(PathFragment path) {
    return path.getPathString().indexOf('-') >= 0;
  }

  // ---------- Implicit dependency extractor

  /*
   * Given a RuleContext, find all the implicit attribute deps aka deps that weren't explicitly set
   * in the build file but are attached behind the scenes to some attribute. This means this
   * function does *not* cover deps attached other ways e.g. toolchain-related implicit deps
   * (see {@link PostAnalysisQueryEnvironment#targetifyValues} for more info on further implicit
   * deps filtering).
   * note: nodes that are depended on both implicitly and explicitly are considered explicit.
   */
  public static ImmutableSet<ConfiguredTargetKey> findImplicitDeps(RuleContext ruleContext) {
    Set<ConfiguredTargetKey> maybeImplicitDeps = CompactHashSet.create();
    Set<ConfiguredTargetKey> explicitDeps = CompactHashSet.create();
    // Consider rule attribute dependencies.
    AttributeMap attributes = ruleContext.attributes();
    for (String attrName : attributes.getAttributeNames()) {
      List<ConfiguredTargetAndData> attrValues =
          ruleContext.getPrerequisiteConfiguredTargets(attrName);
      if (attrValues != null && !attrValues.isEmpty()) {
        if (attributes.isAttributeValueExplicitlySpecified(attrName)) {
          addLabelsAndConfigs(explicitDeps, attrValues);
        } else {
          addLabelsAndConfigs(maybeImplicitDeps, attrValues);
        }
      }
    }

    if (ruleContext.getRule().useToolchainResolution()) {
      // Rules that participate in toolchain resolution implicitly depend on the target platform to
      // check whether it matches the constraints in the target_compatible_with attribute.
      if (ruleContext.getConfiguration().hasFragment(PlatformConfiguration.class)) {
        PlatformConfiguration platformConfiguration =
            ruleContext.getConfiguration().getFragment(PlatformConfiguration.class);
        maybeImplicitDeps.add(
            ConfiguredTargetKey.builder()
                .setLabel(platformConfiguration.getTargetPlatform())
                .setConfigurationKey(BuildConfigurationKey.create(CommonOptions.EMPTY_OPTIONS))
                .build());
      }
    }

    ToolchainCollection<ResolvedToolchainContext> toolchainContexts =
        ruleContext.getToolchainContexts();
    if (toolchainContexts != null) {
      for (ResolvedToolchainContext toolchainContext : toolchainContexts.getContextMap().values()) {
        if (toolchainContext != null) {
          // This logic should stay up to date with the dep creation logic in
          // DependencyResolver#partiallyResolveDependencies.
          BuildConfigurationValue targetConfiguration = ruleContext.getConfiguration();
          for (Label toolchain : toolchainContext.resolvedToolchainLabels()) {
            maybeImplicitDeps.add(
                ConfiguredTargetKey.builder()
                    .setLabel(toolchain)
                    .setConfiguration(targetConfiguration)
                    .setExecutionPlatformLabel(toolchainContext.executionPlatform().label())
                    .build());
          }
        }
      }
    }
    return ImmutableSet.copyOf(Sets.difference(maybeImplicitDeps, explicitDeps));
  }

  private static void addLabelsAndConfigs(
      Set<ConfiguredTargetKey> set, List<ConfiguredTargetAndData> deps) {
    for (ConfiguredTargetAndData dep : deps) {
      // Dereference any aliases that might be present.
      set.add(
          ConfiguredTargetKey.builder()
              .setLabel(dep.getConfiguredTarget().getOriginalLabel())
              .setConfiguration(dep.getConfiguration())
              .build());
    }
  }
}