Line data    Source code

       1             : // Copyright (C) 2009 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.server.git;
      16             : 
      17             : import com.google.gerrit.server.util.RequestContext;
      18             : import com.google.gerrit.server.util.ThreadLocalRequestContext;
      19             : import com.google.gerrit.server.util.ThreadLocalRequestScopePropagator;
      20             : import com.google.inject.Inject;
      21             : import com.google.inject.Key;
      22             : import com.google.inject.OutOfScopeException;
      23             : import com.google.inject.Provider;
      24             : import com.google.inject.Scope;
      25             : import java.util.HashMap;
      26             : import java.util.Map;
      27             : import java.util.concurrent.Callable;
      28             : 
      29           0 : public class PerThreadRequestScope {
      30             :   public interface Scoper {
      31             :     <T> Callable<T> scope(Callable<T> callable);
      32             :   }
      33             : 
      34             :   private static class Context {
      35             :     private final Map<Key<?>, Object> map;
      36             : 
      37           0 :     private Context() {
      38           0 :       map = new HashMap<>();
      39           0 :     }
      40             : 
      41             :     private <T> T get(Key<T> key, Provider<T> creator) {
      42             :       @SuppressWarnings("unchecked")
      43           0 :       T t = (T) map.get(key);
      44           0 :       if (t == null) {
      45           0 :         t = creator.get();
      46           0 :         map.put(key, t);
      47             :       }
      48           0 :       return t;
      49             :     }
      50             :   }
      51             : 
      52             :   public static class Propagator extends ThreadLocalRequestScopePropagator<Context> {
      53             :     @Inject
      54             :     Propagator(ThreadLocalRequestContext local) {
      55           0 :       super(REQUEST, current, local);
      56           0 :     }
      57             : 
      58             :     @Override
      59             :     protected Context continuingContext(Context ctx) {
      60           0 :       return new Context();
      61             :     }
      62             : 
      63             :     public <T> Callable<T> scope(RequestContext requestContext, Callable<T> callable) {
      64           0 :       Context ctx = new Context();
      65           0 :       Callable<T> wrapped = context(requestContext, cleanup(callable));
      66           0 :       return () -> {
      67           0 :         Context old = current.get();
      68           0 :         current.set(ctx);
      69             :         try {
      70           0 :           return wrapped.call();
      71             :         } finally {
      72           0 :           current.set(old);
      73             :         }
      74             :       };
      75             :     }
      76             :   }
      77             : 
      78          16 :   private static final ThreadLocal<Context> current = new ThreadLocal<>();
      79             : 
      80             :   private static Context requireContext() {
      81           0 :     final Context ctx = current.get();
      82           0 :     if (ctx == null) {
      83           0 :       throw new OutOfScopeException("Not in command/request");
      84             :     }
      85           0 :     return ctx;
      86             :   }
      87             : 
      88          16 :   public static final Scope REQUEST =
      89          16 :       new Scope() {
      90             :         @Override
      91             :         public <T> Provider<T> scope(Key<T> key, Provider<T> creator) {
      92           0 :           return new Provider<>() {
      93             :             @Override
      94             :             public T get() {
      95           0 :               return requireContext().get(key, creator);
      96             :             }
      97             : 
      98             :             @Override
      99             :             public String toString() {
     100           0 :               return String.format("%s[%s]", creator, REQUEST);
     101             :             }
     102             :           };
     103             :         }
     104             : 
     105             :         @Override
     106             :         public String toString() {
     107           0 :           return "PerThreadRequestScope.REQUEST";
     108             :         }
     109             :       };
     110             : }