Merge "Add intersection to GroupMembership"

gerrit-server/src/main/java/com/google/gerrit/server/account/GroupMembership.java

@@ -39,6 +39,20 @@ public interface GroupMembership {
    */
   boolean containsAnyOf(Iterable<AccountGroup.UUID> groupIds);
 
+  /**
+   * Returns a set containing an input member of {@code contains(id)} is true.
+   * <p>
+   * This is batch form of contains that returns specific group information.
+   * Implementors may implement the method as:
+   *
+   * <pre>
+   * Set&lt;AccountGroup.UUID&gt; r = Sets.newHashSet();
+   * for (AccountGroup.UUID id : groupIds)
+   *   if (contains(id)) r.add(id);
+   * </pre>
+   */
+  Set<AccountGroup.UUID> intersection(Iterable<AccountGroup.UUID> groupIds);
+
   /**
    * Returns the set of groups that can be determined by the implementation.
    * This may not return all groups the {@link #contains(AccountGroup.UUID)}

gerrit-server/src/main/java/com/google/gerrit/server/account/IncludingGroupMembership.java

@@ -70,6 +70,17 @@ public class IncludingGroupMembership implements GroupMembership {
     return findIncludedGroup(query);
   }
 
+  @Override
+  public Set<AccountGroup.UUID> intersection(Iterable<AccountGroup.UUID> groupIds) {
+    Set<AccountGroup.UUID> r = Sets.newHashSet();
+    for (AccountGroup.UUID id : groupIds) {
+      if (contains(id)) {
+        r.add(id);
+      }
+    }
+    return r;
+  }
+
   private boolean findIncludedGroup(Set<AccountGroup.UUID> query) {
     boolean found = false;
     while (!found && !groupQueue.isEmpty()) {

gerrit-server/src/main/java/com/google/gerrit/server/account/ListGroupMembership.java

@@ -24,7 +24,6 @@ import java.util.Set;
  * GroupMembership over an explicit list.
  */
 public class ListGroupMembership implements GroupMembership {
-
   private final Set<AccountGroup.UUID> groups;
 
   public ListGroupMembership(Iterable<AccountGroup.UUID> groupIds) {
@@ -46,6 +45,11 @@ public class ListGroupMembership implements GroupMembership {
     return false;
   }
 
+  @Override
+  public Set<AccountGroup.UUID> intersection(Iterable<AccountGroup.UUID> groupIds) {
+    return Sets.intersection(ImmutableSet.copyOf(groupIds), groups);
+  }
+
   @Override
   public Set<AccountGroup.UUID> getKnownGroups() {
     return Sets.newHashSet(groups);

gerrit-server/src/main/java/com/google/gerrit/server/account/UniversalGroupBackend.java

@@ -156,6 +156,26 @@ public class UniversalGroupBackend implements GroupBackend {
       return false;
     }
 
+    @Override
+    public Set<AccountGroup.UUID> intersection(Iterable<AccountGroup.UUID> uuids) {
+      Multimap<GroupMembership, AccountGroup.UUID> lookups =
+          ArrayListMultimap.create();
+      for (AccountGroup.UUID uuid : uuids) {
+        GroupMembership m = membership(uuid);
+        if (m == null) {
+          log.warn("Unknown GroupMembership for UUID: " + uuid);
+          continue;
+        }
+        lookups.put(m, uuid);
+      }
+      Set<AccountGroup.UUID> groups = Sets.newHashSet();
+      for (Map.Entry<GroupMembership, Collection<AccountGroup.UUID>> entry
+          : lookups.asMap().entrySet()) {
+        groups.addAll(entry.getKey().intersection(entry.getValue()));
+      }
+      return groups;
+    }
+
     @Override
     public Set<AccountGroup.UUID> getKnownGroups() {
       Set<AccountGroup.UUID> groups = Sets.newHashSet();