Introduce CompoundEvaluationProgressReceiver for combining multiple EvaluationProgressReceivers.

RELNOTES: None
PiperOrigin-RevId: 155542146

src/main/java/com/google/devtools/build/skyframe/CompoundEvaluationProgressReceiver.java

diff --git a/src/main/java/com/google/devtools/build/skyframe/CompoundEvaluationProgressReceiver.java b/src/main/java/com/google/devtools/build/skyframe/CompoundEvaluationProgressReceiver.java
new file mode 100644
index 0000000..32bdf4f
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/skyframe/CompoundEvaluationProgressReceiver.java
@@ -0,0 +1,62 @@
+// Copyright 2017 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.skyframe;
+
+import com.google.common.base.Supplier;
+import com.google.common.collect.ImmutableList;
+
+/**
+ * An {@link EvaluationProgressReceiver} that delegates to a bunch of other
+ * {@link EvaluationProgressReceiver}s.
+ */
+public class CompoundEvaluationProgressReceiver implements EvaluationProgressReceiver {
+  protected final ImmutableList<? extends EvaluationProgressReceiver> receivers;
+
+  protected CompoundEvaluationProgressReceiver(
+      ImmutableList<? extends EvaluationProgressReceiver> receivers) {
+    this.receivers = receivers;
+  }
+
+  public static EvaluationProgressReceiver of(EvaluationProgressReceiver... receivers) {
+    return new CompoundEvaluationProgressReceiver(ImmutableList.copyOf(receivers));
+  }
+
+  @Override
+  public void invalidated(SkyKey skyKey, InvalidationState state) {
+    for (EvaluationProgressReceiver receiver : receivers) {
+      receiver.invalidated(skyKey, state);
+    }
+  }
+
+  @Override
+  public void enqueueing(SkyKey skyKey) {
+    for (EvaluationProgressReceiver receiver : receivers) {
+      receiver.enqueueing(skyKey);
+    }
+  }
+
+  @Override
+  public void computed(SkyKey skyKey, long elapsedTimeNanos) {
+    for (EvaluationProgressReceiver receiver : receivers) {
+      receiver.computed(skyKey, elapsedTimeNanos);
+    }
+  }
+
+  @Override
+  public void evaluated(SkyKey skyKey, Supplier<SkyValue> valueSupplier, EvaluationState state) {
+    for (EvaluationProgressReceiver receiver : receivers) {
+      receiver.evaluated(skyKey, valueSupplier, state);
+    }
+  }
+}