1 files changed, 83 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/actions/CompositeRunfilesSupplier.java b/src/main/java/com/google/devtools/build/lib/actions/CompositeRunfilesSupplier.java
new file mode 100644
index 0000000000..da119ab009
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+++ b/src/main/java/com/google/devtools/build/lib/actions/CompositeRunfilesSupplier.java
@@ -0,0 +1,83 @@
+// Copyright 2015 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.actions;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Maps;
+import com.google.devtools.build.lib.vfs.PathFragment;
+import java.io.IOException;
+import java.util.Map;
+
+/** A {@link RunfilesSupplier} implementation for composing multiple instances. */
+// TODO(michajlo): Move creation to factory constructor and optimize structure of the returned
+// supplier, ie: [] -> EmptyRunfilesSupplier, [singleSupplier] -> supplier,
+// [Empty, single] -> single, and so on.
+public class CompositeRunfilesSupplier implements RunfilesSupplier {
+
+  private final ImmutableList<RunfilesSupplier> suppliers;
+
+  /** Create an instance with {@code first} taking precedence over {@code second}. */
+  public CompositeRunfilesSupplier(RunfilesSupplier first, RunfilesSupplier second) {
+    this(ImmutableList.of(first, second));
+  }
+
+  /**
+   * Create an instance combining all of {@code suppliers}, with earlier elements taking precedence.
+   */
+  public CompositeRunfilesSupplier(Iterable<RunfilesSupplier> suppliers) {
+    this.suppliers = ImmutableList.copyOf(suppliers);
+  }
+
+  @Override
+  public Iterable<Artifact> getArtifacts() {
+    ImmutableSet.Builder<Artifact> result = ImmutableSet.builder();
+    for (RunfilesSupplier supplier : suppliers) {
+      result.addAll(supplier.getArtifacts());
+    }
+    return result.build();
+  }
+
+  @Override
+  public ImmutableSet<PathFragment> getRunfilesDirs() {
+    ImmutableSet.Builder<PathFragment> result = ImmutableSet.builder();
+    for (RunfilesSupplier supplier : suppliers) {
+      result.addAll(supplier.getRunfilesDirs());
+    }
+    return result.build();
+  }
+
+  @Override
+  public ImmutableMap<PathFragment, Map<PathFragment, Artifact>> getMappings() throws IOException {
+    Map<PathFragment, Map<PathFragment, Artifact>> result = Maps.newHashMap();
+    for (RunfilesSupplier supplier : suppliers) {
+      Map<PathFragment, Map<PathFragment, Artifact>> mappings = supplier.getMappings();
+      for (Map.Entry<PathFragment, Map<PathFragment, Artifact>> entry : mappings.entrySet()) {
+        result.putIfAbsent(entry.getKey(), entry.getValue());
+      }
+    }
+    return ImmutableMap.copyOf(result);
+  }
+
+  @Override
+  public ImmutableList<Artifact> getManifests() {
+    ImmutableList.Builder<Artifact> result = ImmutableList.builder();
+    for (RunfilesSupplier supplier : suppliers) {
+      result.addAll(supplier.getManifests());
+    }
+    return result.build();
+  }
+}