1 files changed, 113 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/git/PerThreadRequestScope.java b/java/com/google/gerrit/server/git/PerThreadRequestScope.java
new file mode 100644
index 0000000000..a4719a911e
--- /dev/null
+++ b/java/com/google/gerrit/server/git/PerThreadRequestScope.java
@@ -0,0 +1,113 @@
+// 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.config.RequestScopedReviewDbProvider;
+import com.google.gerrit.server.util.RequestContext;
+import com.google.gerrit.server.util.ThreadLocalRequestContext;
+import com.google.gerrit.server.util.ThreadLocalRequestScopePropagator;
+import com.google.inject.Inject;
+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;
+import java.util.concurrent.Callable;
+
+public class PerThreadRequestScope {
+  public interface Scoper {
+    <T> Callable<T> scope(Callable<T> callable);
+  }
+
+  private static class Context {
+    private final Map<Key<?>, Object> map;
+
+    private Context() {
+      map = new HashMap<>();
+    }
+
+    private <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;
+    }
+  }
+
+  public static class Propagator extends ThreadLocalRequestScopePropagator<Context> {
+    @Inject
+    Propagator(
+        ThreadLocalRequestContext local,
+        Provider<RequestScopedReviewDbProvider> dbProviderProvider) {
+      super(REQUEST, current, local, dbProviderProvider);
+    }
+
+    @Override
+    protected Context continuingContext(Context ctx) {
+      return new Context();
+    }
+
+    public <T> Callable<T> scope(RequestContext requestContext, Callable<T> callable) {
+      Context ctx = new Context();
+      Callable<T> wrapped = context(requestContext, cleanup(callable));
+      return () -> {
+        Context old = current.get();
+        current.set(ctx);
+        try {
+          return wrapped.call();
+        } finally {
+          current.set(old);
+        }
+      };
+    }
+  }
+
+  private static final ThreadLocal<Context> current = new ThreadLocal<>();
+
+  private static Context requireContext() {
+    final Context ctx = current.get();
+    if (ctx == null) {
+      throw new OutOfScopeException("Not in command/request");
+    }
+    return ctx;
+  }
+
+  public static final Scope REQUEST =
+      new Scope() {
+        @Override
+        public <T> Provider<T> scope(Key<T> key, Provider<T> creator) {
+          return new Provider<T>() {
+            @Override
+            public T get() {
+              return requireContext().get(key, creator);
+            }
+
+            @Override
+            public String toString() {
+              return String.format("%s[%s]", creator, REQUEST);
+            }
+          };
+        }
+
+        @Override
+        public String toString() {
+          return "PerThreadRequestScope.REQUEST";
+        }
+      };
+}