Dissolve gerrit-server top-level directory

Change-Id: I538512dfe0f1bea774c01fdd45fa410a45634011

java/com/google/gerrit/server/git/receive/AllRefsWatcher.java

@@ -0,0 +1,50 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// 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.gerrit.server.git.receive;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.gerrit.server.git.HookUtil;
+import java.util.Map;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.transport.AdvertiseRefsHook;
+import org.eclipse.jgit.transport.BaseReceivePack;
+import org.eclipse.jgit.transport.ServiceMayNotContinueException;
+import org.eclipse.jgit.transport.UploadPack;
+
+/**
+ * Hook that scans all refs and holds onto the results reference.
+ *
+ * <p>This allows a caller who has an {@code AllRefsWatcher} instance to get the full map of refs in
+ * the repo, even if refs are filtered by a later hook or filter.
+ */
+class AllRefsWatcher implements AdvertiseRefsHook {
+  private Map<String, Ref> allRefs;
+
+  @Override
+  public void advertiseRefs(BaseReceivePack rp) throws ServiceMayNotContinueException {
+    allRefs = HookUtil.ensureAllRefsAdvertised(rp);
+  }
+
+  @Override
+  public void advertiseRefs(UploadPack uploadPack) {
+    throw new UnsupportedOperationException();
+  }
+
+  Map<String, Ref> getAllRefs() {
+    checkState(allRefs != null, "getAllRefs() only valid after refs were advertised");
+    return allRefs;
+  }
+}