Use Guice injection to pass GerritServer to HttpServlets

If an HttpServlet requires the GerritServer instance to do its work
(and most do) we can pass it through the constructor by way of Guice
rather than trying to obtain it during the init method.

Signed-off-by: Shawn O. Pearce <sop@google.com>

src/main/java/com/google/gerrit/server/BecomeAnyAccountLoginServlet.java

@@ -18,16 +18,14 @@ import com.google.gerrit.client.Gerrit;
 import com.google.gerrit.client.reviewdb.Account;
 import com.google.gerrit.client.reviewdb.ReviewDb;
 import com.google.gerrit.client.rpc.Common;
-import com.google.gwtjsonrpc.server.XsrfException;
 import com.google.gwtorm.client.OrmException;
+import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
-import javax.servlet.ServletConfig;
-import javax.servlet.ServletException;
 import javax.servlet.ServletOutputStream;
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServlet;
@@ -45,21 +43,13 @@ public class BecomeAnyAccountLoginServlet extends HttpServlet {
     }
   }
 
-  private boolean allowed;
-  private GerritServer server;
+  private final boolean allowed;
+  private final GerritServer server;
 
-  @Override
-  public void init(final ServletConfig config) throws ServletException {
-    super.init(config);
+  @Inject
+  BecomeAnyAccountLoginServlet(final GerritServer gs) {
+    server = gs;
     allowed = isAllowed();
-
-    try {
-      server = GerritServer.getInstance();
-    } catch (OrmException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    } catch (XsrfException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    }
   }
 
   @Override

src/main/java/com/google/gerrit/server/CatServlet.java

@@ -24,8 +24,8 @@ import com.google.gerrit.client.reviewdb.PatchSet;
 import com.google.gerrit.client.reviewdb.Project;
 import com.google.gerrit.client.reviewdb.ReviewDb;
 import com.google.gerrit.client.rpc.Common;
-import com.google.gwtjsonrpc.server.XsrfException;
 import com.google.gwtorm.client.OrmException;
+import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
 import eu.medsea.mimeutil.MimeType;
@@ -66,21 +66,19 @@ import javax.servlet.http.HttpServletResponse;
 @Singleton
 public class CatServlet extends HttpServlet {
   private static final MimeType ZIP = new MimeType("application/zip");
-  private GerritServer server;
-  private SecureRandom rng;
+  private final GerritServer server;
+  private final SecureRandom rng;
   private FileTypeRegistry registry;
 
+  @Inject
+  CatServlet(final GerritServer gs) {
+    server = gs;
+    rng = new SecureRandom();
+  }
+
   @Override
   public void init(final ServletConfig config) throws ServletException {
     super.init(config);
-    try {
-      server = GerritServer.getInstance();
-    } catch (OrmException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    } catch (XsrfException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    }
-    rng = new SecureRandom();
     registry = FileTypeRegistry.getInstance();
   }
 

src/main/java/com/google/gerrit/server/GerritServer.java

@@ -48,6 +48,7 @@ import com.google.gwtorm.client.OrmException;
 import com.google.gwtorm.client.Transaction;
 import com.google.gwtorm.jdbc.Database;
 import com.google.gwtorm.jdbc.SimpleDataSource;
+import com.google.inject.Singleton;
 
 import net.sf.ehcache.Cache;
 import net.sf.ehcache.CacheManager;
@@ -95,6 +96,7 @@ import javax.servlet.http.HttpServletRequest;
 import javax.sql.DataSource;
 
 /** Global server-side state for Gerrit. */
+@Singleton
 public class GerritServer {
   private static final Logger log = LoggerFactory.getLogger(GerritServer.class);
   private static DataSource datasource;

src/main/java/com/google/gerrit/server/GerritServletConfig.java

@@ -15,16 +15,25 @@
 package com.google.gerrit.server;
 
 import com.google.gerrit.server.ssh.SshServlet;
+import com.google.gwtjsonrpc.server.XsrfException;
+import com.google.gwtorm.client.OrmException;
+import com.google.inject.AbstractModule;
+import com.google.inject.ConfigurationException;
 import com.google.inject.Guice;
 import com.google.inject.Injector;
+import com.google.inject.Key;
+import com.google.inject.Module;
 import com.google.inject.servlet.GuiceServletContextListener;
 import com.google.inject.servlet.ServletModule;
 
+import java.security.ProviderException;
+
+import javax.servlet.ServletContextEvent;
+
 /** Configures the web application environment for Gerrit Code Review. */
 public class GerritServletConfig extends GuiceServletContextListener {
-  @Override
-  protected Injector getInjector() {
-    return Guice.createInjector(new ServletModule() {
+  private static Module createServletModule() {
+    return new ServletModule() {
       @Override
       protected void configureServlets() {
         filter("/*").through(UrlRewriteFilter.class);
@@ -65,6 +74,48 @@ public class GerritServletConfig extends GuiceServletContextListener {
       private void rpc(String name, Class<? extends GerritJsonServlet> clazz) {
         serve("/gerrit/rpc/" + name).with(clazz);
       }
-    });
+    };
+  }
+
+  private static Module createDatabaseModule() {
+    return new AbstractModule() {
+      @Override
+      protected void configure() {
+        try {
+          bind(GerritServer.class).toInstance(GerritServer.getInstance(true));
+        } catch (OrmException e) {
+          addError(e);
+        } catch (XsrfException e) {
+          addError(e);
+        }
+      }
+    };
+  }
+
+  private final Injector injector =
+      Guice.createInjector(createDatabaseModule(), createServletModule());
+
+  @Override
+  protected Injector getInjector() {
+    return injector;
+  }
+
+  @Override
+  public void contextInitialized(final ServletContextEvent event) {
+    super.contextInitialized(event);
+  }
+
+  @Override
+  public void contextDestroyed(final ServletContextEvent event) {
+    try {
+      final GerritServer gs = injector.getInstance(Key.get(GerritServer.class));
+      gs.closeDataSource();
+    } catch (ConfigurationException ce) {
+      // Assume it never started.
+    } catch (ProviderException ce) {
+      // Assume it never started.
+    }
+
+    super.contextDestroyed(event);
   }
 }

src/main/java/com/google/gerrit/server/HostPageServlet.java

@@ -18,8 +18,7 @@ import com.google.gerrit.client.data.GerritConfig;
 import com.google.gerrit.client.reviewdb.Account;
 import com.google.gerrit.client.rpc.Common;
 import com.google.gwt.user.server.rpc.RPCServletUtils;
-import com.google.gwtjsonrpc.server.XsrfException;
-import com.google.gwtorm.client.OrmException;
+import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
 import org.spearce.jgit.lib.Constants;
@@ -44,23 +43,20 @@ import javax.servlet.http.HttpServletResponse;
 @SuppressWarnings("serial")
 @Singleton
 public class HostPageServlet extends HttpServlet {
-  private GerritServer server;
+  private final GerritServer server;
   private String canonicalUrl;
   private boolean wantSSL;
   private Document hostDoc;
 
+  @Inject
+  HostPageServlet(final GerritServer gs) {
+    server = gs;
+  }
+
   @Override
   public void init(ServletConfig config) throws ServletException {
     super.init(config);
 
-    try {
-      server = GerritServer.getInstance();
-    } catch (OrmException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    } catch (XsrfException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    }
-
     final File sitePath = server.getSitePath();
     canonicalUrl = server.getCanonicalURL();
     wantSSL = canonicalUrl != null && canonicalUrl.startsWith("https:");

src/main/java/com/google/gerrit/server/StaticServlet.java

@@ -15,8 +15,7 @@
 package com.google.gerrit.server;
 
 import com.google.gwt.user.server.rpc.RPCServletUtils;
-import com.google.gwtjsonrpc.server.XsrfException;
-import com.google.gwtorm.client.OrmException;
+import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
 import org.spearce.jgit.util.NB;
@@ -29,8 +28,6 @@ import java.io.OutputStream;
 import java.util.HashMap;
 import java.util.zip.GZIPOutputStream;
 
-import javax.servlet.ServletConfig;
-import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -90,22 +87,11 @@ public class StaticServlet extends HttpServlet {
     return out.toByteArray();
   }
 
-  private File staticBase;
+  private final File staticBase;
   
-  @Override
-  public void init(final ServletConfig config) throws ServletException {
-    super.init(config);
-
-    final GerritServer srv;
-    try {
-      srv = GerritServer.getInstance();
-    } catch (OrmException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    } catch (XsrfException e) {
-      throw new ServletException("Cannot load GerritServer", e);
-    }
-
-    final File p = srv.getSitePath();
+  @Inject
+  StaticServlet(final GerritServer gs) {
+    final File p = gs.getSitePath();
     staticBase = p != null ? new File(p, "static") : null;
   }
 

src/main/java/com/google/gerrit/server/UrlRewriteFilter.java

@@ -20,7 +20,6 @@ import com.google.gerrit.client.reviewdb.Change;
 import com.google.gerrit.client.reviewdb.RevId;
 import com.google.gerrit.client.reviewdb.ReviewDb;
 import com.google.gerrit.client.rpc.Common;
-import com.google.gwtjsonrpc.server.XsrfException;
 import com.google.gwtorm.client.OrmException;
 import com.google.inject.Singleton;
 
@@ -72,15 +71,8 @@ public class UrlRewriteFilter implements Filter {
 
   private FilterConfig config;
 
-  public void init(final FilterConfig config) throws ServletException {
+  public void init(final FilterConfig config) {
     this.config = config;
-    try {
-      GerritServer.getInstance();
-    } catch (OrmException e) {
-      throw new ServletException("Cannot initialize GerritServer", e);
-    } catch (XsrfException e) {
-      throw new ServletException("Cannot initialize GerritServer", e);
-    }
   }
 
   public void destroy() {