Adds TransitiveTraversalFunction that loads transitive deps of a target

Unlike TransitiveTargetFunction, it does not return nested sets of the
traversed targets. Used primarily for its side effects of loading the
transitive targets into the graph.

--
MOS_MIGRATED_REVID=99388411

1 files changed, 91 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTraversalFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTraversalFunction.java
new file mode 100644
index 0000000000..910c8c31b3
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTraversalFunction.java
@@ -0,0 +1,91 @@
+// 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.skyframe;
+
+import com.google.devtools.build.lib.collect.nestedset.NestedSet;
+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 com.google.devtools.build.lib.skyframe.TransitiveTraversalFunction.DummyAccumulator;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+import com.google.devtools.build.skyframe.ValueOrException2;
+
+import java.util.Map.Entry;
+
+/**
+ * This class is like {@link TransitiveTargetFunction}, but the values it returns do not contain
+ * {@link NestedSet}s. It should be used only when the side-effects of {@link
+ * TransitiveTargetFunction} are desired (i.e., loading transitive targets and their packages, and
+ * emitting error events).
+ */
+public class TransitiveTraversalFunction extends TransitiveBaseTraversalFunction<DummyAccumulator> {
+
+  @Override
+  SkyKey getKey(Label label) {
+    return TransitiveTraversalValue.key(label);
+  }
+
+  @Override
+  DummyAccumulator processTarget(Label label, TargetAndErrorIfAny targetAndErrorIfAny) {
+    return DummyAccumulator.INSTANCE;
+  }
+
+  @Override
+  void processDeps(DummyAccumulator processedTargets, EventHandler eventHandler,
+      TargetAndErrorIfAny targetAndErrorIfAny,
+      Iterable<Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>>>
+          depEntries) {
+    Target target = targetAndErrorIfAny.getTarget();
+    for (Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>> entry :
+        depEntries) {
+      Label depLabel = (Label) entry.getKey().argument();
+      TransitiveTraversalValue transitiveTraversalValue;
+      try {
+        transitiveTraversalValue = (TransitiveTraversalValue) entry.getValue().get();
+        if (transitiveTraversalValue == null) {
+          continue;
+        }
+      } catch (NoSuchPackageException | NoSuchTargetException e) {
+        maybeReportErrorAboutMissingEdge(target, depLabel, e, eventHandler);
+        continue;
+      }
+      if (transitiveTraversalValue.getErrorLoadingTarget() != null) {
+        maybeReportErrorAboutMissingEdge(target, depLabel,
+            transitiveTraversalValue.getErrorLoadingTarget(), eventHandler);
+      }
+    }
+  }
+
+  @Override
+  SkyValue computeSkyValue(TargetAndErrorIfAny targetAndErrorIfAny,
+      DummyAccumulator processedTargets) {
+    NoSuchTargetException errorLoadingTarget = targetAndErrorIfAny.getErrorLoadingTarget();
+    return errorLoadingTarget == null
+        ? TransitiveTraversalValue.SUCCESSFUL_TRANSITIVE_TRAVERSAL_VALUE
+        : TransitiveTraversalValue.unsuccessfulTransitiveTraversal(errorLoadingTarget);
+  }
+
+  /**
+   * Because {@link TransitiveTraversalFunction} is invoked only when its side-effects are desired,
+   * this value accumulator has nothing to keep track of.
+   */
+  static class DummyAccumulator {
+    static final DummyAccumulator INSTANCE = new DummyAccumulator();
+
+    private DummyAccumulator() {}
+  }
+}