Use persistent cache provided by libModule for offline reindex

Gerrit offline reindexing ignores persistent cache implementation
provided as libModule and always generates caches using H2
implementation. This fix allows to use a different persistent cache
backend.

Using different cache implementation during the offline reindexing
and at runtime causes situation when Gerrit starts without any
precomputed caches which significantly impacts overall performance.
On the other hand offline reindexing cannot reuse existing caches
which impacts reindexing performance.

Bug: Issue 13464
Change-Id: I36305282e8ea583dfb37f629e41d219762c3b4a3

java/com/google/gerrit/pgm/Reindex.java

@@ -29,6 +29,10 @@ import com.google.gerrit.lifecycle.LifecycleManager;
 import com.google.gerrit.lucene.LuceneIndexModule;
 import com.google.gerrit.pgm.util.BatchProgramModule;
 import com.google.gerrit.pgm.util.SiteProgram;
+import com.google.gerrit.server.LibModuleLoader;
+import com.google.gerrit.server.LibModuleType;
+import com.google.gerrit.server.ModuleOverloader;
+import com.google.gerrit.server.cache.h2.H2CacheModule;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.index.IndexModule;
@@ -159,6 +163,7 @@ public class Reindex extends SiteProgram {
     }
     modules.add(indexModule);
     modules.add(new BatchProgramModule());
+    modules.add(new H2CacheModule());
     modules.add(
         new FactoryModule() {
           @Override
@@ -167,7 +172,9 @@ public class Reindex extends SiteProgram {
           }
         });
 
-    return dbInjector.createChildInjector(modules);
+    return dbInjector.createChildInjector(
+        ModuleOverloader.override(
+            modules, LibModuleLoader.loadModules(dbInjector, LibModuleType.SYS_MODULE)));
   }
 
   private void overrideConfig() {

java/com/google/gerrit/pgm/util/BatchProgramModule.java

@@ -38,7 +38,6 @@ import com.google.gerrit.server.account.Realm;
 import com.google.gerrit.server.account.ServiceUserClassifierImpl;
 import com.google.gerrit.server.account.externalids.ExternalIdModule;
 import com.google.gerrit.server.cache.CacheRemovalListener;
-import com.google.gerrit.server.cache.h2.H2CacheModule;
 import com.google.gerrit.server.cache.mem.DefaultMemoryCacheModule;
 import com.google.gerrit.server.change.ChangeAttributeFactory;
 import com.google.gerrit.server.change.ChangeJson;
@@ -153,7 +152,7 @@ public class BatchProgramModule extends FactoryModule {
     install(new BatchGitModule());
     install(new DefaultPermissionBackendModule());
     install(new DefaultMemoryCacheModule());
-    install(new H2CacheModule());
+
     install(new ExternalIdModule());
     install(new GroupModule());
     install(new NoteDbModule());