Fix server startup when replication.config exists

The addition of the per-request RefControl cache broke push
replication as the PushOp "request" could not locate a Guice
binding for the cache.

Use the same trick we do with MergeOp to setup a per-operation
"request" scope for Guice.

Change-Id: I0cecbad4809493f43cb2fec3624b1a53e38fb48f

gerrit-server/src/main/java/com/google/gerrit/server/git/PerThreadRequestScope.java

@@ -0,0 +1,85 @@
+// Copyright (C) 2009 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;
+
+import com.google.gerrit.server.RequestCleanup;
+import com.google.inject.Key;
+import com.google.inject.OutOfScopeException;
+import com.google.inject.Provider;
+import com.google.inject.Scope;
+
+import java.util.HashMap;
+import java.util.Map;
+
+class PerThreadRequestScope {
+  private static final ThreadLocal<PerThreadRequestScope> current =
+      new ThreadLocal<PerThreadRequestScope>();
+
+  private static PerThreadRequestScope getContext() {
+    final PerThreadRequestScope ctx = current.get();
+    if (ctx == null) {
+      throw new OutOfScopeException("Not in command/request");
+    }
+    return ctx;
+  }
+
+  static PerThreadRequestScope set(PerThreadRequestScope ctx) {
+    PerThreadRequestScope old = current.get();
+    current.set(ctx);
+    return old;
+  }
+
+  static final Scope REQUEST = new Scope() {
+    public <T> Provider<T> scope(final Key<T> key, final Provider<T> creator) {
+      return new Provider<T>() {
+        public T get() {
+          return getContext().get(key, creator);
+        }
+
+        @Override
+        public String toString() {
+          return String.format("%s[%s]", creator, REQUEST);
+        }
+      };
+    }
+
+    @Override
+    public String toString() {
+      return "PerThreadRequestScope.REQUEST";
+    }
+  };
+
+  private static final Key<RequestCleanup> RC_KEY =
+      Key.get(RequestCleanup.class);
+
+  final RequestCleanup cleanup;
+  private final Map<Key<?>, Object> map;
+
+  PerThreadRequestScope() {
+    cleanup = new RequestCleanup();
+    map = new HashMap<Key<?>, Object>();
+    map.put(RC_KEY, cleanup);
+  }
+
+  synchronized <T> T get(Key<T> key, Provider<T> creator) {
+    @SuppressWarnings("unchecked")
+    T t = (T) map.get(key);
+    if (t == null) {
+      t = creator.get();
+      map.put(key, t);
+    }
+    return t;
+  }
+}