Support to retrieve a child project via REST

Change-Id: Ic38f1ca10b6731073e5a11ad72c8753adbaff235
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

Documentation/rest-api-projects.txt

@@ -535,6 +535,38 @@ returned that describe the child projects.
   ]
 ----
 
+[[get-child-project]]
+Get Child Project
+~~~~~~~~~~~~~~~~~
+[verse]
+'GET /projects/link:#project-name[\{project-name\}]/children/link:#project-name[\{project-name\}]'
+
+Retrieves a child project.
+
+.Request
+----
+  GET /projects/Public-Plugins/children/plugins%2Freplication HTTP/1.0
+----
+
+As response a link:#project-info[ProjectInfo] entity is returned that
+describes the child project.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json;charset=UTF-8
+
+  )]}'
+  {
+    "kind": "gerritcodereview#project",
+    "id": "plugins%2Freplication",
+    "name": "plugins/replication",
+    "parent": "Public-Plugins",
+    "description": "Copies to other servers using the Git protocol"
+  }
+----
+
 [[dashboard-endpoints]]
 Dashboard Endpoints
 -------------------

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/rest/project/GetChildProjectIT.java

@@ -0,0 +1,109 @@
+// Copyright (C) 2013 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.acceptance.rest.project;
+
+import static com.google.gerrit.acceptance.git.GitUtil.createProject;
+import static com.google.gerrit.acceptance.rest.project.ProjectAssert.assertProjectInfo;
+import static org.junit.Assert.assertEquals;
+
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.AccountCreator;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.acceptance.RestSession;
+import com.google.gerrit.acceptance.SshSession;
+import com.google.gerrit.acceptance.TestAccount;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+import com.google.inject.Inject;
+
+import com.jcraft.jsch.JSchException;
+
+import org.apache.http.HttpStatus;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class GetChildProjectIT extends AbstractDaemonTest {
+
+  @Inject
+  private AccountCreator accounts;
+
+  @Inject
+  private AllProjectsName allProjects;
+
+  @Inject
+  private ProjectCache projectCache;
+
+  private TestAccount admin;
+  private RestSession session;
+
+  @Before
+  public void setUp() throws Exception {
+    admin =
+        accounts.create("admin", "admin@example.com", "Administrator",
+            "Administrators");
+    session = new RestSession(admin);
+  }
+
+  @Test
+  public void getNonExistingChildProject_NotFound() throws IOException {
+    assertEquals(HttpStatus.SC_NOT_FOUND,
+        GET("/projects/" + allProjects.get() + "/children/non-existing").getStatusCode());
+  }
+
+  @Test
+  public void getNonChildProject_NotFound() throws IOException, JSchException {
+    SshSession sshSession = new SshSession(admin);
+    Project.NameKey p1 = new Project.NameKey("p1");
+    createProject(sshSession, p1.get());
+    Project.NameKey p2 = new Project.NameKey("p2");
+    createProject(sshSession, p2.get());
+    assertEquals(HttpStatus.SC_NOT_FOUND,
+        GET("/projects/" + p1.get() + "/children/" + p2.get()).getStatusCode());
+  }
+
+  @Test
+  public void getChildProject() throws IOException, JSchException {
+    SshSession sshSession = new SshSession(admin);
+    Project.NameKey child = new Project.NameKey("p1");
+    createProject(sshSession, child.get());
+    RestResponse r = GET("/projects/" + allProjects.get() + "/children/" + child.get());
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    ProjectInfo childInfo =
+        (new Gson()).fromJson(r.getReader(),
+            new TypeToken<ProjectInfo>() {}.getType());
+    assertProjectInfo(projectCache.get(child).getProject(), childInfo);
+  }
+
+  @Test
+  public void getGrandChildProject_NotFound() throws IOException, JSchException {
+    SshSession sshSession = new SshSession(admin);
+    Project.NameKey child = new Project.NameKey("p1");
+    createProject(sshSession, child.get());
+    Project.NameKey grandChild = new Project.NameKey("p1.1");
+    createProject(sshSession, grandChild.get(), child);
+    assertEquals(HttpStatus.SC_NOT_FOUND,
+        GET("/projects/" + allProjects.get() + "/children/" + grandChild.get())
+            .getStatusCode());
+  }
+
+  private RestResponse GET(String endpoint) throws IOException {
+    return session.get(endpoint);
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/project/ChildProjectsCollection.java

@@ -14,24 +14,29 @@
 
 package com.google.gerrit.server.project;
 
+import com.google.common.collect.Iterables;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
+import com.google.gerrit.extensions.restapi.TopLevelResource;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
 public class ChildProjectsCollection implements
     ChildCollection<ProjectResource, ChildProjectResource> {
   private final Provider<ListChildProjects> list;
+  private final Provider<ProjectsCollection> projectsCollection;
   private final DynamicMap<RestView<ChildProjectResource>> views;
 
   @Inject
   ChildProjectsCollection(Provider<ListChildProjects> list,
+      Provider<ProjectsCollection> projectsCollection,
       DynamicMap<RestView<ChildProjectResource>> views) {
     this.list = list;
+    this.projectsCollection = projectsCollection;
     this.views = views;
   }
 
@@ -44,6 +49,13 @@ public class ChildProjectsCollection implements
   @Override
   public ChildProjectResource parse(ProjectResource parent, IdString id)
       throws ResourceNotFoundException {
+    ProjectResource p =
+        projectsCollection.get().parse(TopLevelResource.INSTANCE, id);
+    ProjectState pp =
+        Iterables.getFirst(p.getControl().getProjectState().parents(), null);
+    if (pp != null && parent.getNameKey().equals(pp.getProject().getNameKey())) {
+      return new ChildProjectResource(parent, p.getControl());
+    }
     throw new ResourceNotFoundException(id);
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/project/GetChildProject.java

@@ -0,0 +1,33 @@
+// Copyright (C) 2013 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.project;
+
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.server.project.ProjectJson.ProjectInfo;
+import com.google.inject.Inject;
+
+public class GetChildProject implements RestReadView<ChildProjectResource> {
+  private final ProjectJson json;
+
+  @Inject
+  GetChildProject(ProjectJson json) {
+    this.json = json;
+  }
+
+  @Override
+  public ProjectInfo apply(ChildProjectResource rsrc) {
+    return json.format(rsrc.getChild().getProject());
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/project/Module.java

@@ -43,6 +43,7 @@ public class Module extends RestApiModule {
     put(PROJECT_KIND, "parent").to(SetParent.class);
 
     child(PROJECT_KIND, "children").to(ChildProjectsCollection.class);
+    get(CHILD_PROJECT_KIND).to(GetChildProject.class);
 
     get(PROJECT_KIND, "HEAD").to(GetHead.class);
     put(PROJECT_KIND, "HEAD").to(SetHead.class);