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, 58 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTraversalValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTraversalValue.java
new file mode 100644
index 0000000000..8216381994
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTraversalValue.java
@@ -0,0 +1,58 @@
+// 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.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
+import com.google.devtools.build.lib.packages.NoSuchTargetException;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import javax.annotation.Nullable;
+
+/**
+ * A <i>transitive</i> target reference that, when built in skyframe, loads the entire
+ * transitive closure of a target. Contains no information about the targets traversed.
+ */
+@Immutable
+@ThreadSafe
+public class TransitiveTraversalValue implements SkyValue {
+
+  @Nullable
+  private final NoSuchTargetException errorLoadingTarget;
+
+  static final TransitiveTraversalValue SUCCESSFUL_TRANSITIVE_TRAVERSAL_VALUE =
+      new TransitiveTraversalValue(null);
+
+  private TransitiveTraversalValue(@Nullable NoSuchTargetException errorLoadingTarget) {
+    this.errorLoadingTarget = errorLoadingTarget;
+  }
+
+  static TransitiveTraversalValue unsuccessfulTransitiveTraversal(
+      NoSuchTargetException errorLoadingTarget) {
+    return new TransitiveTraversalValue(errorLoadingTarget);
+  }
+
+  /** Returns the error, if any, from loading the target. */
+  @Nullable
+  public NoSuchTargetException getErrorLoadingTarget() {
+    return errorLoadingTarget;
+  }
+
+  @ThreadSafe
+  public static SkyKey key(Label label) {
+    return new SkyKey(SkyFunctions.TRANSITIVE_TRAVERSAL, label);
+  }
+}