1 files changed, 106 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/project/ChildProjects.java b/java/com/google/gerrit/server/project/ChildProjects.java
new file mode 100644
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+++ b/java/com/google/gerrit/server/project/ChildProjects.java
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+// Copyright (C) 2017 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 static java.util.stream.Collectors.toList;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Multimap;
+import com.google.gerrit.extensions.common.ProjectInfo;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackendException;
+import com.google.gerrit.server.permissions.ProjectPermission;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/** Retrieve child projects (ie. projects whose access inherits from a given parent.) */
+@Singleton
+public class ChildProjects {
+  private final ProjectCache projectCache;
+  private final PermissionBackend permissionBackend;
+  private final AllProjectsName allProjects;
+  private final ProjectJson json;
+
+  @Inject
+  ChildProjects(
+      ProjectCache projectCache,
+      PermissionBackend permissionBackend,
+      AllProjectsName allProjectsName,
+      ProjectJson json) {
+    this.projectCache = projectCache;
+    this.permissionBackend = permissionBackend;
+    this.allProjects = allProjectsName;
+    this.json = json;
+  }
+
+  /** Gets all child projects recursively. */
+  public List<ProjectInfo> list(Project.NameKey parent) throws PermissionBackendException {
+    Map<Project.NameKey, Project> projects = readAllReadableProjects();
+    Multimap<Project.NameKey, Project.NameKey> children = parentToChildren(projects);
+    PermissionBackend.WithUser perm = permissionBackend.currentUser();
+
+    List<ProjectInfo> results = new ArrayList<>();
+    depthFirstFormat(results, perm, projects, children, parent);
+    return results;
+  }
+
+  private Map<Project.NameKey, Project> readAllReadableProjects() {
+    Map<Project.NameKey, Project> projects = new HashMap<>();
+    for (Project.NameKey name : projectCache.all()) {
+      ProjectState c = projectCache.get(name);
+      if (c != null && c.statePermitsRead()) {
+        projects.put(c.getNameKey(), c.getProject());
+      }
+    }
+    return projects;
+  }
+
+  /** Map of parent project to direct child. */
+  private Multimap<Project.NameKey, Project.NameKey> parentToChildren(
+      Map<Project.NameKey, Project> projects) {
+    Multimap<Project.NameKey, Project.NameKey> m = ArrayListMultimap.create();
+    for (Map.Entry<Project.NameKey, Project> e : projects.entrySet()) {
+      if (!allProjects.equals(e.getKey())) {
+        m.put(e.getValue().getParent(allProjects), e.getKey());
+      }
+    }
+    return m;
+  }
+
+  private void depthFirstFormat(
+      List<ProjectInfo> results,
+      PermissionBackend.WithUser perm,
+      Map<Project.NameKey, Project> projects,
+      Multimap<Project.NameKey, Project.NameKey> children,
+      Project.NameKey parent)
+      throws PermissionBackendException {
+    List<Project.NameKey> canSee =
+        perm.filter(ProjectPermission.ACCESS, children.get(parent)).stream()
+            .sorted()
+            .collect(toList());
+    children.removeAll(parent); // removing all entries prevents cycles.
+
+    for (Project.NameKey c : canSee) {
+      results.add(json.format(projects.get(c)));
+      depthFirstFormat(results, perm, projects, children, c);
+    }
+  }
+}