Support listing child projects via REST

It is now possible to list the direct child projects of a project via
REST by GET on /projects/*/children/.

Change-Id: If57b44118c6742f7d0bef751f2be0b8abebfc0a2
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

Documentation/rest-api-projects.txt

@@ -483,6 +483,58 @@ The response is the streamed output of the garbage collection.
   done.
 ----
 
+[[child-project-endpoints]]
+Child Project Endpoints
+-----------------------
+
+[[list-child-projects]]
+List Child Projects
+~~~~~~~~~~~~~~~~~~~
+[verse]
+'GET /projects/link:#project-name[\{project-name\}]/children/'
+
+List the direct child projects of a project.
+
+.Request
+----
+  GET /projects/Public-Plugins/children/ HTTP/1.0
+----
+
+As result a list of link:#project-info[ProjectInfo] entries is
+returned that describe the child projects.
+
+.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"
+    },
+    {
+      "kind": "gerritcodereview#project",
+      "id": "plugins%2Freviewnotes",
+      "name": "plugins/reviewnotes",
+      "parent": "Public-Plugins",
+      "description": "Annotates merged commits using notes on refs/notes/review."
+    },
+    {
+      "kind": "gerritcodereview#project",
+      "id": "plugins%2Fsingleusergroup",
+      "name": "plugins/singleusergroup",
+      "parent": "Public-Plugins",
+      "description": "GroupBackend enabling users to be directly added to access rules"
+    }
+  ]
+----
+
 [[dashboard-endpoints]]
 Dashboard Endpoints
 -------------------

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/git/GitUtil.java

@@ -18,6 +18,7 @@ import com.google.common.collect.Iterables;
 import com.google.gerrit.acceptance.SshSession;
 import com.google.gerrit.acceptance.TempFileUtil;
 import com.google.gerrit.acceptance.TestAccount;
+import com.google.gerrit.reviewdb.client.Project;
 
 import com.jcraft.jsch.JSch;
 import com.jcraft.jsch.JSchException;
@@ -74,7 +75,21 @@ public class GitUtil {
 
   public static void createProject(SshSession s, String name)
       throws JSchException, IOException {
-    s.exec("gerrit create-project --empty-commit --name \"" + name + "\"");
+    createProject(s, name, null);
+  }
+
+  public static void createProject(SshSession s, String name, Project.NameKey parent)
+      throws JSchException, IOException {
+    StringBuilder b = new StringBuilder();
+    b.append("gerrit create-project --empty-commit --name \"");
+    b.append(name);
+    b.append("\"");
+    if (parent != null) {
+      b.append(" --parent \"");
+      b.append(parent.get());
+      b.append("\"");
+    }
+    s.exec(b.toString());
   }
 
   public static Git cloneProject(String url) throws GitAPIException, IOException {

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

@@ -0,0 +1,99 @@
+// 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 org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static com.google.gerrit.acceptance.rest.project.ProjectAssert.assertProjects;
+
+import com.google.gson.reflect.TypeToken;
+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.gson.Gson;
+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;
+import java.util.Arrays;
+import java.util.List;
+
+public class ListChildProjectsIT extends AbstractDaemonTest {
+
+  @Inject
+  private AccountCreator accounts;
+
+  @Inject
+  private AllProjectsName allProjects;
+
+  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 listChildrenOfNonExistingProject_NotFound() throws IOException {
+    assertEquals(HttpStatus.SC_NOT_FOUND,
+        GET("/projects/non-existing/children/").getStatusCode());
+  }
+
+  @Test
+  public void listNoChildren() throws IOException {
+    RestResponse r = GET("/projects/" + allProjects.get() + "/children/");
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    List<ProjectInfo> children =
+        (new Gson()).fromJson(r.getReader(),
+            new TypeToken<List<ProjectInfo>>() {}.getType());
+    assertTrue(children.isEmpty());
+  }
+
+  @Test
+  public void listChildren() throws IOException, JSchException {
+    SshSession sshSession = new SshSession(admin);
+    Project.NameKey child1 = new Project.NameKey("p1");
+    createProject(sshSession, child1.get());
+    Project.NameKey child2 = new Project.NameKey("p2");
+    createProject(sshSession, child2.get());
+    createProject(sshSession, "p1.1", child1);
+
+    RestResponse r = GET("/projects/" + allProjects.get() + "/children/");
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    List<ProjectInfo> children =
+        (new Gson()).fromJson(r.getReader(),
+            new TypeToken<List<ProjectInfo>>() {}.getType());
+    assertProjects(Arrays.asList(child1, child2), children);
+  }
+
+  private RestResponse GET(String endpoint) throws IOException {
+    return session.get(endpoint);
+  }
+}

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

@@ -15,18 +15,36 @@
 package com.google.gerrit.acceptance.rest.project;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
+import com.google.common.base.Predicate;
 import com.google.common.base.Strings;
+import com.google.common.collect.Iterables;
 import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.project.ProjectState;
 
+import java.util.List;
 import java.util.Set;
 
 public class ProjectAssert {
 
+  public static void assertProjects(Iterable<Project.NameKey> expected,
+      List<ProjectInfo> actual) {
+    for (final Project.NameKey p : expected) {
+      ProjectInfo info = Iterables.find(actual, new Predicate<ProjectInfo>() {
+        @Override
+        public boolean apply(ProjectInfo info) {
+          return new Project.NameKey(info.name).equals(p);
+        }}, null);
+      assertNotNull("missing project: " + p, info);
+      actual.remove(info);
+    }
+    assertTrue("unexpected projects: " + actual, actual.isEmpty());
+  }
+
   public static void assertProjectInfo(Project project, ProjectInfo info) {
     if (info.name != null) {
       // 'name' is not set if returned in a map

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

@@ -19,4 +19,9 @@ public class ProjectInfo {
   public String name;
   public String parent;
   public String description;
+
+  @Override
+  public String toString() {
+    return name;
+  }
 }

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

@@ -0,0 +1,34 @@
+// 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.RestView;
+import com.google.inject.TypeLiteral;
+
+public class ChildProjectResource extends ProjectResource {
+  public static final TypeLiteral<RestView<ChildProjectResource>> CHILD_PROJECT_KIND =
+      new TypeLiteral<RestView<ChildProjectResource>>() {};
+
+  private final ProjectControl child;
+
+  ChildProjectResource(ProjectResource project, ProjectControl child) {
+    super(project);
+    this.child = child;
+  }
+
+  public ProjectControl getChild() {
+    return child;
+  }
+}

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

@@ -0,0 +1,54 @@
+// 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.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.inject.Inject;
+import com.google.inject.Provider;
+
+public class ChildProjectsCollection implements
+    ChildCollection<ProjectResource, ChildProjectResource> {
+  private final Provider<ListChildProjects> list;
+  private final DynamicMap<RestView<ChildProjectResource>> views;
+
+  @Inject
+  ChildProjectsCollection(Provider<ListChildProjects> list,
+      DynamicMap<RestView<ChildProjectResource>> views) {
+    this.list = list;
+    this.views = views;
+  }
+
+  @Override
+  public RestView<ProjectResource> list() throws ResourceNotFoundException,
+      AuthException {
+    return list.get();
+  }
+
+  @Override
+  public ChildProjectResource parse(ProjectResource parent, IdString id)
+      throws ResourceNotFoundException {
+    throw new ResourceNotFoundException(id);
+  }
+
+  @Override
+  public DynamicMap<RestView<ChildProjectResource>> views() {
+    return views;
+  }
+}

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

@@ -0,0 +1,55 @@
+// 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.common.collect.Lists;
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.project.ProjectJson.ProjectInfo;
+import com.google.inject.Inject;
+
+import java.util.List;
+
+public class ListChildProjects implements RestReadView<ProjectResource> {
+
+  private final ProjectCache projectCache;
+  private final AllProjectsName allProjects;
+  private final ProjectJson json;
+
+  @Inject
+  ListChildProjects(ProjectCache projectCache, AllProjectsName allProjects,
+      ProjectJson json) {
+    this.projectCache = projectCache;
+    this.allProjects = allProjects;
+    this.json = json;
+  }
+
+  @Override
+  public List<ProjectInfo> apply(ProjectResource rsrc) {
+    List<ProjectInfo> childProjects = Lists.newArrayList();
+    for (Project.NameKey projectName : projectCache.all()) {
+      ProjectState e = projectCache.get(projectName);
+      if (e == null) {
+        // If we can't get it from the cache, pretend it's not present.
+        continue;
+      }
+      if (rsrc.getNameKey().equals(e.getProject().getParent(allProjects))) {
+        childProjects.add(json.format(e.getProject()));
+      }
+    }
+    return childProjects;
+  }
+}

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

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.gerrit.server.project.ChildProjectResource.CHILD_PROJECT_KIND;
 import static com.google.gerrit.server.project.DashboardResource.DASHBOARD_KIND;
 import static com.google.gerrit.server.project.ProjectResource.PROJECT_KIND;
 
@@ -29,6 +30,7 @@ public class Module extends RestApiModule {
     bind(DashboardsCollection.class);
 
     DynamicMap.mapOf(binder(), PROJECT_KIND);
+    DynamicMap.mapOf(binder(), CHILD_PROJECT_KIND);
     DynamicMap.mapOf(binder(), DASHBOARD_KIND);
 
     put(PROJECT_KIND).to(PutProject.class);
@@ -40,6 +42,8 @@ public class Module extends RestApiModule {
     get(PROJECT_KIND, "parent").to(GetParent.class);
     put(PROJECT_KIND, "parent").to(SetParent.class);
 
+    child(PROJECT_KIND, "children").to(ChildProjectsCollection.class);
+
     get(PROJECT_KIND, "HEAD").to(GetHead.class);
     put(PROJECT_KIND, "HEAD").to(SetHead.class);
 

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

@@ -29,6 +29,10 @@ public class ProjectResource implements RestResource {
     this.control = control;
   }
 
+  ProjectResource(ProjectResource rsrc) {
+    this.control = rsrc.getControl();
+  }
+
   public String getName() {
     return control.getProject().getName();
   }