1 files changed, 126 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/constraints/EnvironmentCollection.java b/src/main/java/com/google/devtools/build/lib/analysis/constraints/EnvironmentCollection.java
new file mode 100644
index 0000000000..1ce5f1cb4a
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+++ b/src/main/java/com/google/devtools/build/lib/analysis/constraints/EnvironmentCollection.java
@@ -0,0 +1,126 @@
+// Copyright 2015 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.constraints;
+
+import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableMultimap;
+import com.google.common.collect.ImmutableSet;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.packages.EnvironmentGroup;
+import com.google.devtools.build.lib.syntax.Label;
+
+import java.util.Map;
+
+/**
+ * Contains a set of {@link Environment} labels and their associated groups.
+ */
+@Immutable
+public class EnvironmentCollection {
+  private final ImmutableMultimap<EnvironmentGroup, Label> map;
+
+  private EnvironmentCollection(ImmutableMultimap<EnvironmentGroup, Label> map) {
+    this.map = map;
+  }
+
+  /**
+   * Stores an environment's build label along with the group it belongs to.
+   */
+  static class EnvironmentWithGroup {
+    private final Label environment;
+    private final EnvironmentGroup group;
+    EnvironmentWithGroup(Label environment, EnvironmentGroup group) {
+      this.environment = environment;
+      this.group = group;
+    }
+    Label environment() { return environment; }
+    EnvironmentGroup group() { return group; }
+  }
+
+  /**
+   * Returns the build labels of each environment in this collection, ordered by
+   * their insertion order in {@link Builder}.
+   */
+  ImmutableCollection<Label> getEnvironments() {
+    return map.values();
+  }
+
+  /**
+   * Returns the set of groups the environments in this collection belong to, ordered by
+   * their insertion order in {@link Builder}
+   */
+  ImmutableSet<EnvironmentGroup> getGroups() {
+    return map.keySet();
+  }
+
+  /**
+   * Returns the build labels of each environment in this collection paired with the
+   * group each environment belongs to, ordered by their insertion order in {@link Builder}.
+   */
+  ImmutableCollection<EnvironmentWithGroup> getGroupedEnvironments() {
+    ImmutableSet.Builder<EnvironmentWithGroup> builder = ImmutableSet.builder();
+    for (Map.Entry<EnvironmentGroup, Label> entry : map.entries()) {
+      builder.add(new EnvironmentWithGroup(entry.getValue(), entry.getKey()));
+    }
+    return builder.build();
+  }
+
+  /**
+   * Returns the environments in this collection that belong to the given group, ordered by
+   * their insertion order in {@link Builder}. If no environments belong to the given group,
+   * returns an empty collection.
+   */
+  ImmutableCollection<Label> getEnvironments(EnvironmentGroup group) {
+    return map.get(group);
+  }
+
+  /**
+   * An empty collection.
+   */
+  static final EnvironmentCollection EMPTY =
+      new EnvironmentCollection(ImmutableMultimap.<EnvironmentGroup, Label>of());
+
+  static class Builder {
+    private final ImmutableMultimap.Builder<EnvironmentGroup, Label> mapBuilder =
+        ImmutableMultimap.builder();
+
+    /**
+     * Inserts the given environment / owning group pair.
+     */
+    Builder put(EnvironmentGroup group, Label environment) {
+      mapBuilder.put(group, environment);
+      return this;
+    }
+
+    /**
+     * Inserts the given set of environments, all belonging to the specified group.
+     */
+    Builder putAll(EnvironmentGroup group, Iterable<Label> environments) {
+      mapBuilder.putAll(group, environments);
+      return this;
+    }
+
+    /**
+     * Inserts the contents of another {@link EnvironmentCollection} into this one.
+     */
+    Builder putAll(EnvironmentCollection other) {
+      mapBuilder.putAll(other.map);
+      return this;
+    }
+
+    EnvironmentCollection build() {
+      return new EnvironmentCollection(mapBuilder.build());
+    }
+  }
+}