Extract base class from TransitiveTargetFunction

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MOS_MIGRATED_REVID=99386094

1 files changed, 376 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveBaseTraversalFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveBaseTraversalFunction.java
new file mode 100644
index 0000000000..36484551e6
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveBaseTraversalFunction.java
@@ -0,0 +1,376 @@
+// Copyright 2015 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.skyframe;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Multimap;
+import com.google.devtools.build.lib.events.Event;
+import com.google.devtools.build.lib.events.EventHandler;
+import com.google.devtools.build.lib.packages.AspectDefinition;
+import com.google.devtools.build.lib.packages.Attribute;
+import com.google.devtools.build.lib.packages.InputFile;
+import com.google.devtools.build.lib.packages.NoSuchPackageException;
+import com.google.devtools.build.lib.packages.NoSuchTargetException;
+import com.google.devtools.build.lib.packages.NoSuchThingException;
+import com.google.devtools.build.lib.packages.OutputFile;
+import com.google.devtools.build.lib.packages.Package;
+import com.google.devtools.build.lib.packages.PackageGroup;
+import com.google.devtools.build.lib.packages.Rule;
+import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.packages.TargetUtils;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+import com.google.devtools.build.skyframe.ValueOrException2;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import javax.annotation.Nullable;
+
+/**
+ * This class can be extended to define {@link SkyFunction}s that traverse a target and its
+ * transitive dependencies and return values based on that traversal.
+ *
+ * <p>The {@code TProcessedTargets} type parameter represents the result of processing a target and
+ * its transitive dependencies.
+ *
+ * <p>{@code TransitiveBaseTraversalFunction} asks for one to be constructed via {@link
+ * #processTarget}, and then asks for it to be updated based on the current target's
+ * attributes' dependencies via {@link #processDeps}, and then asks for it to be updated based
+ * on the current target' aspects' dependencies via {@link #processDeps}. Finally, it calls
+ * {@link #computeSkyValue} with the {#code ProcessedTargets} to get the {@link SkyValue} to
+ * return.
+ */
+abstract class TransitiveBaseTraversalFunction<TProcessedTargets>
+    implements SkyFunction {
+
+  /**
+   * Returns a {@link SkyKey} corresponding to the traversal of a target specified by {@code label}
+   * and its transitive dependencies.
+   *
+   * <p>Extenders of this class should implement this function to return a key with their
+   * specialized {@link SkyFunction}'s name.
+   *
+   * <p>{@link TransitiveBaseTraversalFunction} calls this for each dependency of a target, and
+   * then gets their values from the environment.
+   *
+   * <p>The key's {@link SkyFunction} may throw at most {@link NoSuchPackageException} and
+   * {@link NoSuchTargetException}. Other exception types are not handled by {@link
+   * TransitiveBaseTraversalFunction}.
+   */
+  abstract SkyKey getKey(Label label);
+
+  abstract TProcessedTargets processTarget(Label label,
+      TargetAndErrorIfAny targetAndErrorIfAny);
+
+  abstract void processDeps(TProcessedTargets processedTargets, EventHandler eventHandler,
+      TargetAndErrorIfAny targetAndErrorIfAny,
+      Iterable<Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>>>
+          depEntries);
+
+  /**
+   * Returns a {@link SkyValue} based on the target and any errors it has, and the values
+   * accumulated across it and a traversal of its transitive dependencies.
+   */
+  abstract SkyValue computeSkyValue(TargetAndErrorIfAny targetAndErrorIfAny,
+      TProcessedTargets processedTargets);
+
+  @Override
+  public SkyValue compute(SkyKey key, Environment env)
+      throws TransitiveBaseTraversalFunctionException {
+    Label label = (Label) key.argument();
+    LoadTargetResults loadTargetResults;
+    try {
+      loadTargetResults = loadTarget(env, label);
+    } catch (NoSuchTargetException e) {
+      throw new TransitiveBaseTraversalFunctionException(e);
+    } catch (NoSuchPackageException e) {
+      throw new TransitiveBaseTraversalFunctionException(e);
+    }
+    LoadTargetResultsType loadTargetResultsType = loadTargetResults.getType();
+    if (loadTargetResultsType.equals(LoadTargetResultsType.VALUES_MISSING)) {
+      return null;
+    }
+    Preconditions.checkState(
+        loadTargetResultsType.equals(LoadTargetResultsType.TARGET_AND_ERROR_IF_ANY),
+        loadTargetResultsType);
+    TargetAndErrorIfAny targetAndErrorIfAny = (TargetAndErrorIfAny) loadTargetResults;
+    TProcessedTargets processedTargets = processTarget(label, targetAndErrorIfAny);
+
+    // Process deps from attributes of current target.
+    Iterable<SkyKey> labelDepKeys = getLabelDepKeys(targetAndErrorIfAny.getTarget());
+    Set<Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>>>
+        labelDepEntries = env.getValuesOrThrow(labelDepKeys, NoSuchPackageException.class,
+        NoSuchTargetException.class).entrySet();
+    processDeps(processedTargets, env.getListener(), targetAndErrorIfAny, labelDepEntries);
+    if (env.valuesMissing()) {
+      return null;
+    }
+
+    // Process deps from aspects.
+    Iterable<SkyKey> labelAspectKeys = getLabelAspectKeys(targetAndErrorIfAny.getTarget(), env);
+    Set<Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>>>
+        labelAspectEntries = env.getValuesOrThrow(labelAspectKeys, NoSuchPackageException.class,
+        NoSuchTargetException.class).entrySet();
+    processDeps(processedTargets, env.getListener(), targetAndErrorIfAny, labelAspectEntries);
+    if (env.valuesMissing()) {
+      return null;
+    }
+
+    return computeSkyValue(targetAndErrorIfAny, processedTargets);
+  }
+
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return Label.print(((Label) skyKey.argument()));
+  }
+
+  private Iterable<SkyKey> getLabelAspectKeys(Target target, Environment env) {
+    List<SkyKey> depKeys = Lists.newArrayList();
+    if (target instanceof Rule) {
+      Multimap<Attribute, Label> transitions =
+          ((Rule) target).getTransitions(Rule.NO_NODEP_ATTRIBUTES);
+      for (Entry<Attribute, Label> entry : transitions.entries()) {
+        SkyKey packageKey = PackageValue.key(entry.getValue().getPackageIdentifier());
+        try {
+          PackageValue pkgValue = (PackageValue) env.getValueOrThrow(packageKey,
+              NoSuchThingException.class);
+          if (pkgValue == null) {
+            continue;
+          }
+          Collection<Label> labels = AspectDefinition.visitAspectsIfRequired(target, entry.getKey(),
+              pkgValue.getPackage().getTarget(entry.getValue().getName())).values();
+          for (Label label : labels) {
+            depKeys.add(getKey(label));
+          }
+        } catch (NoSuchThingException e) {
+          // Do nothing. This error was handled when we computed the corresponding
+          // TransitiveTargetValue.
+        }
+      }
+    }
+    return depKeys;
+  }
+
+  private Iterable<SkyKey> getLabelDepKeys(Target target) {
+    List<SkyKey> depKeys = Lists.newArrayList();
+    for (Label depLabel : getLabelDeps(target)) {
+      depKeys.add(getKey(depLabel));
+    }
+    return depKeys;
+  }
+
+  // TODO(bazel-team): Unify this logic with that in LabelVisitor, and possibly DependencyResolver.
+  private static Iterable<Label> getLabelDeps(Target target) {
+    final Set<Label> labels = new HashSet<>();
+    if (target instanceof OutputFile) {
+      Rule rule = ((OutputFile) target).getGeneratingRule();
+      labels.add(rule.getLabel());
+      visitTargetVisibility(target, labels);
+    } else if (target instanceof InputFile) {
+      visitTargetVisibility(target, labels);
+    } else if (target instanceof Rule) {
+      visitTargetVisibility(target, labels);
+      visitRule(target, labels);
+    } else if (target instanceof PackageGroup) {
+      visitPackageGroup((PackageGroup) target, labels);
+    }
+    return labels;
+  }
+
+  private static void visitRule(Target target, Set<Label> labels) {
+    labels.addAll(((Rule) target).getLabels(Rule.NO_NODEP_ATTRIBUTES));
+  }
+
+  private static void visitTargetVisibility(Target target, Set<Label> labels) {
+    labels.addAll(target.getVisibility().getDependencyLabels());
+  }
+
+  private static void visitPackageGroup(PackageGroup packageGroup, Set<Label> labels) {
+    labels.addAll(packageGroup.getIncludes());
+  }
+
+  protected void maybeReportErrorAboutMissingEdge(Target target, Label depLabel,
+      NoSuchThingException e, EventHandler eventHandler) {
+    if (e instanceof NoSuchTargetException) {
+      NoSuchTargetException nste = (NoSuchTargetException) e;
+      if (depLabel.equals(nste.getLabel())) {
+        eventHandler.handle(Event.error(TargetUtils.getLocationMaybe(target),
+            TargetUtils.formatMissingEdge(target, depLabel, e)));
+      }
+    } else if (e instanceof NoSuchPackageException) {
+      NoSuchPackageException nspe = (NoSuchPackageException) e;
+      if (nspe.getPackageId().equals(depLabel.getPackageIdentifier())) {
+        eventHandler.handle(Event.error(TargetUtils.getLocationMaybe(target),
+            TargetUtils.formatMissingEdge(target, depLabel, e)));
+      }
+    }
+  }
+
+  enum LoadTargetResultsType {
+    VALUES_MISSING,
+    TARGET_AND_ERROR_IF_ANY
+  }
+
+  interface LoadTargetResults {
+    LoadTargetResultsType getType();
+  }
+
+  private static class ValuesMissing implements LoadTargetResults {
+
+    private static final ValuesMissing INSTANCE = new ValuesMissing();
+
+    private ValuesMissing() {}
+
+    @Override
+    public LoadTargetResultsType getType() {
+      return LoadTargetResultsType.VALUES_MISSING;
+    }
+  }
+
+  interface TargetAndErrorIfAny {
+
+    boolean isPackageLoadedSuccessfully();
+
+    @Nullable NoSuchTargetException getErrorLoadingTarget();
+
+    Target getTarget();
+  }
+
+  private static class TargetAndErrorIfAnyImpl implements TargetAndErrorIfAny, LoadTargetResults {
+
+    private final boolean packageLoadedSuccessfully;
+    @Nullable private final NoSuchTargetException errorLoadingTarget;
+    private final Target target;
+
+    private TargetAndErrorIfAnyImpl(boolean packageLoadedSuccessfully,
+        @Nullable NoSuchTargetException errorLoadingTarget, Target target) {
+      this.packageLoadedSuccessfully = packageLoadedSuccessfully;
+      this.errorLoadingTarget = errorLoadingTarget;
+      this.target = target;
+    }
+
+    @Override
+    public LoadTargetResultsType getType() {
+      return LoadTargetResultsType.TARGET_AND_ERROR_IF_ANY;
+    }
+
+    @Override
+    public boolean isPackageLoadedSuccessfully() {
+      return packageLoadedSuccessfully;
+    }
+
+    @Override
+    @Nullable
+    public NoSuchTargetException getErrorLoadingTarget() {
+      return errorLoadingTarget;
+    }
+
+    @Override
+    public Target getTarget() {
+      return target;
+    }
+  }
+
+  private static LoadTargetResults loadTarget(Environment env, Label label)
+      throws NoSuchTargetException, NoSuchPackageException {
+    SkyKey packageKey = PackageValue.key(label.getPackageIdentifier());
+    SkyKey targetKey = TargetMarkerValue.key(label);
+
+    boolean packageLoadedSuccessfully;
+    Target target;
+    NoSuchTargetException errorLoadingTarget = null;
+    try {
+      TargetMarkerValue targetValue = (TargetMarkerValue) env.getValueOrThrow(targetKey,
+          NoSuchTargetException.class, NoSuchPackageException.class);
+      if (targetValue == null) {
+        return ValuesMissing.INSTANCE;
+      }
+      PackageValue packageValue = (PackageValue) env.getValueOrThrow(packageKey,
+          NoSuchPackageException.class);
+      if (packageValue == null) {
+        return ValuesMissing.INSTANCE;
+      }
+
+      packageLoadedSuccessfully = true;
+      try {
+        target = packageValue.getPackage().getTarget(label.getName());
+      } catch (NoSuchTargetException unexpected) {
+        // Not expected since the TargetMarkerFunction would have failed earlier if the Target
+        // was not present.
+        throw new IllegalStateException(unexpected);
+      }
+    } catch (NoSuchTargetException e) {
+      if (!e.hasTarget()) {
+        throw e;
+      }
+
+      // We know that a Target may be extracted, but we need to get it out of the Package
+      // (which is known to be in error).
+      Package pkg;
+      try {
+        PackageValue packageValue = (PackageValue) env.getValueOrThrow(packageKey,
+            NoSuchPackageException.class);
+        if (packageValue == null) {
+          return ValuesMissing.INSTANCE;
+        }
+        throw new IllegalStateException(
+            "Expected bad package: " + label.getPackageIdentifier());
+      } catch (NoSuchPackageException nsp) {
+        pkg = Preconditions.checkNotNull(nsp.getPackage(), label.getPackageIdentifier());
+      }
+      try {
+        target = pkg.getTarget(label.getName());
+      } catch (NoSuchTargetException nste) {
+        throw new IllegalStateException("Expected target to exist", nste);
+      }
+
+      errorLoadingTarget = e;
+      packageLoadedSuccessfully = false;
+    }
+    return new TargetAndErrorIfAnyImpl(packageLoadedSuccessfully, errorLoadingTarget, target);
+  }
+
+  /**
+   * Used to declare all the exception types that can be wrapped in the exception thrown by
+   * {@link TransitiveTraversalFunction#compute}.
+   */
+  static class TransitiveBaseTraversalFunctionException extends SkyFunctionException {
+    /**
+     * Used to propagate an error from a direct target dependency to the target that depended on
+     * it.
+     */
+    public TransitiveBaseTraversalFunctionException(NoSuchPackageException e) {
+      super(e, Transience.PERSISTENT);
+    }
+
+    /**
+     * In nokeep_going mode, used to propagate an error from a direct target dependency to the
+     * target that depended on it.
+     *
+     * <p>In keep_going mode, used the same way, but only for targets that could not be loaded at
+     * all (we proceed with transitive loading on targets that contain errors).</p>
+     */
+    public TransitiveBaseTraversalFunctionException(NoSuchTargetException e) {
+      super(e, Transience.PERSISTENT);
+    }
+  }
+}