Support retrieving of non-direct child projects via REST

To retrieve a non-direct child project the parameter 'recursive' must
be specified:
  GET /projects/myParent/children/myGrandChild?recursive

Without the 'recursive' flag being set only direct child projects can
be retrieved.

Change-Id: Ia702665efcd5a7ca59bfd9d9a0cc6eccc9ed1d9c
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

Documentation/rest-api-projects.txt

@@ -598,7 +598,8 @@ Get Child Project
 [verse]
 'GET /projects/link:#project-name[\{project-name\}]/children/link:#project-name[\{project-name\}]'
 
-Retrieves a child project.
+Retrieves a child project. If a non-direct child project should be
+retrieved the parameter `recursive` must be set.
 
 .Request
 ----

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

@@ -103,6 +103,23 @@ public class GetChildProjectIT extends AbstractDaemonTest {
             .getStatusCode());
   }
 
+  @Test
+  public void getGrandChildProjectWithRecursiveFlag() 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);
+    RestResponse r =
+        GET("/projects/" + allProjects.get() + "/children/" + grandChild.get()
+            + "?recursive");
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    ProjectInfo grandChildInfo =
+        (new Gson()).fromJson(r.getReader(), new TypeToken<ProjectInfo>() {}.getType());
+    assertProjectInfo(projectCache.get(grandChild).getProject(), grandChildInfo);
+  }
+
   private RestResponse GET(String endpoint) throws IOException {
     return session.get(endpoint);
   }

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

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.project;
 
+import com.google.common.collect.Iterables;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.inject.TypeLiteral;
 
@@ -31,4 +32,11 @@ public class ChildProjectResource extends ProjectResource {
   public ProjectControl getChild() {
     return child;
   }
+
+  public boolean isDirectChild() {
+    ProjectState parent =
+        Iterables.getFirst(child.getProjectState().parents(), null);
+    return parent != null
+        && getNameKey().equals(parent.getProject().getNameKey());
+  }
 }

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

@@ -14,7 +14,6 @@
 
 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;
@@ -53,10 +52,10 @@ public class ChildProjectsCollection implements
       throws ResourceNotFoundException, IOException {
     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());
+    for (ProjectState pp : p.getControl().getProjectState().parents()) {
+      if (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

@@ -14,11 +14,17 @@
 
 package com.google.gerrit.server.project;
 
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestReadView;
 import com.google.gerrit.server.project.ProjectJson.ProjectInfo;
 import com.google.inject.Inject;
 
+import org.kohsuke.args4j.Option;
+
 public class GetChildProject implements RestReadView<ChildProjectResource> {
+  @Option(name = "--recursive", usage = "to list child projects recursively")
+  private boolean recursive;
+
   private final ProjectJson json;
 
   @Inject
@@ -27,7 +33,11 @@ public class GetChildProject implements RestReadView<ChildProjectResource> {
   }
 
   @Override
-  public ProjectInfo apply(ChildProjectResource rsrc) {
-    return json.format(rsrc.getChild().getProject());
+  public ProjectInfo apply(ChildProjectResource rsrc)
+      throws ResourceNotFoundException {
+    if (recursive || rsrc.isDirectChild()) {
+      return json.format(rsrc.getChild().getProject());
+    }
+    throw new ResourceNotFoundException(rsrc.getName());
   }
 }