1 files changed, 82 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/Aspect.java b/src/main/java/com/google/devtools/build/lib/analysis/Aspect.java
new file mode 100644
index 0000000000..3f4a06e274
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+++ b/src/main/java/com/google/devtools/build/lib/analysis/Aspect.java
@@ -0,0 +1,82 @@
+// 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.analysis;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.UnmodifiableIterator;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * Extra information about a configured target computed on request of a dependent.
+ *
+ * <p>Analogous to {@link ConfiguredTarget}: contains a bunch of transitive info providers, which
+ * are merged with the providers of the associated configured target before they are passed to
+ * the configured target factories that depend on the configured target to which this aspect is
+ * added.
+ *
+ * <p>Aspects are created alongside configured targets on request from dependents.
+ */
+@Immutable
+public final class Aspect implements Iterable<TransitiveInfoProvider> {
+  private final
+      ImmutableMap<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider> providers;
+
+  private Aspect(
+      ImmutableMap<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider> providers) {
+    this.providers = providers;
+  }
+
+  /**
+   * Returns the providers created by the aspect.
+   */
+  public ImmutableMap<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider>
+      getProviders() {
+    return providers;
+  }
+
+  @Override
+  public UnmodifiableIterator<TransitiveInfoProvider> iterator() {
+    return providers.values().iterator();
+  }
+
+  /**
+   * Builder for {@link Aspect}.
+   */
+  public static class Builder {
+    private final Map<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider>
+        providers = new LinkedHashMap<>();
+
+    /**
+     * Adds a provider to the aspect.
+     */
+    public Builder addProvider(
+        Class<? extends TransitiveInfoProvider> key, TransitiveInfoProvider value) {
+      Preconditions.checkNotNull(key);
+      Preconditions.checkNotNull(value);
+      AnalysisUtils.checkProvider(key);
+      Preconditions.checkState(!providers.containsKey(key));
+      providers.put(key, value);
+      return this;
+    }
+
+    public Aspect build() {
+      return new Aspect(ImmutableMap.copyOf(providers));
+    }
+  }
+}
+\ No newline at end of file