Brings Gerrit docs back to life

After the regression introduced by [1] the Gerrit static
documentation was not available anymore in the standard Jetty embedded
server scenario. This change is the ideal completion of the refactoring
of the Jetty-controlled static resources serving legacy logic into
the new Gerrit-driven ResourceServlet mechanism.

[1] https://gerrit-review.googlesource.com/#/c/72085/

Change-Id: If0a52a34a2e1ae1030541b8a2c0d041eafe32af7

gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/StaticModule.java

@@ -38,6 +38,8 @@ import java.nio.file.FileSystem;
 import java.nio.file.Path;
 
 import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
 
 public class StaticModule extends ServletModule {
   public static final String CACHE = "static_content";
@@ -57,6 +59,7 @@ public class StaticModule extends ServletModule {
         "/projects/*");
 
   private static final String GWT_UI_SERVLET = "GwtUiServlet";
+  private static final String DOC_SERVLET = "DocServlet";
 
   private final GerritOptions options;
   private Paths paths;
@@ -75,6 +78,8 @@ public class StaticModule extends ServletModule {
 
   @Override
   protected void configureServlets() {
+    serveRegex("^/Documentation/(.+)$").with(
+        Key.get(HttpServlet.class, Names.named(DOC_SERVLET)));
     serve("/static/*").with(SiteStaticDirectoryServlet.class);
     install(new CacheModule() {
       @Override
@@ -91,6 +96,26 @@ public class StaticModule extends ServletModule {
     }
   }
 
+  @Provides
+  @Singleton
+  @Named(DOC_SERVLET)
+  HttpServlet getDocServlet(@Named(CACHE) Cache<Path, Resource> cache) {
+    Paths p = getPaths();
+    if (p.warFs != null) {
+      return new WarDocServlet(cache, p.warFs);
+    } else {
+      return new HttpServlet() {
+        private static final long serialVersionUID = 1L;
+
+        @Override
+        protected void service(HttpServletRequest req,
+            HttpServletResponse resp) throws IOException {
+          resp.sendError(HttpServletResponse.SC_NOT_FOUND);
+        }
+      };
+    }
+  }
+
   private class GwtUiModule extends ServletModule {
     @Override
     public void configureServlets() {

gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/WarDocServlet.java

@@ -0,0 +1,36 @@
+// Copyright (C) 2015 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.httpd.raw;
+
+import com.google.common.cache.Cache;
+
+import java.nio.file.FileSystem;
+import java.nio.file.Path;
+
+class WarDocServlet extends ResourceServlet {
+  private static final long serialVersionUID = 1L;
+
+  private final FileSystem warFs;
+
+  WarDocServlet(Cache<Path, Resource> cache, FileSystem warFs) {
+    super(cache, false);
+    this.warFs = warFs;
+  }
+
+  @Override
+  protected Path getResourcePath(String pathInfo) {
+    return warFs.getPath("/Documentation/" + pathInfo);
+  }
+}