Merge "Support to inherit project level plugin configuration"

Documentation/dev-plugins.txt

@@ -401,6 +401,20 @@ is no need for a plugin to parse the `project.config` file on its own:
                        .getBoolean("enabled", false);
 ----
 
+It is also possible to get missing configuration parameters inherited
+from the parent projects:
+
+[source,java]
+----
+  @Inject
+  private com.google.gerrit.server.config.PluginConfigFactory cfg;
+
+  ...
+
+  boolean enabled = cfg.getWithInheritance(project, "helloworld")
+                       .getBoolean("enabled", false);
+----
+
 Project owners can edit the project configuration by fetching the
 `refs/meta/config` branch, editing the `project.config` file and
 pushing the commit back.

gerrit-server/src/main/java/com/google/gerrit/server/config/PluginConfig.java

@@ -15,18 +15,53 @@
 package com.google.gerrit.server.config;
 
 import com.google.common.base.Objects;
+import com.google.common.collect.Iterables;
+import com.google.gerrit.server.git.ProjectConfig;
+import com.google.gerrit.server.project.ProjectState;
 
 import org.eclipse.jgit.lib.Config;
 
+import java.util.Arrays;
+import java.util.Set;
+
 public class PluginConfig {
   private static final String PLUGIN = "plugin";
 
   private final String pluginName;
-  private final Config cfg;
+  private Config cfg;
+  private final ProjectConfig projectConfig;
 
   public PluginConfig(String pluginName, Config cfg) {
+    this(pluginName, cfg, null);
+  }
+
+  public PluginConfig(String pluginName, Config cfg, ProjectConfig projectConfig) {
     this.pluginName = pluginName;
     this.cfg = cfg;
+    this.projectConfig = projectConfig;
+  }
+
+  PluginConfig withInheritance(ProjectState.Factory projectStateFactory) {
+    if (projectConfig == null) {
+      return this;
+    }
+
+    ProjectState state = projectStateFactory.create(projectConfig);
+    ProjectState parent = Iterables.getFirst(state.parents(), null);
+    if (parent != null) {
+      PluginConfig parentPluginConfig =
+          parent.getConfig().getPluginConfig(pluginName)
+              .withInheritance(projectStateFactory);
+      Set<String> allNames = cfg.getNames(PLUGIN, pluginName);
+      cfg = new Config(cfg);
+      for (String name : parentPluginConfig.cfg.getNames(PLUGIN, pluginName)) {
+        if (!allNames.contains(name)) {
+          cfg.setStringList(PLUGIN, pluginName, name, Arrays
+              .asList(parentPluginConfig.cfg.getStringList(PLUGIN, pluginName, name)));
+        }
+      }
+    }
+    return this;
   }
 
   public String getString(String name) {

gerrit-server/src/main/java/com/google/gerrit/server/config/PluginConfigFactory.java

@@ -27,11 +27,14 @@ import org.eclipse.jgit.lib.Config;
 public class PluginConfigFactory {
   private final Config cfg;
   private final ProjectCache projectCache;
+  private final ProjectState.Factory projectStateFactory;
 
   @Inject
-  PluginConfigFactory(@GerritServerConfig Config cfg, ProjectCache projectCache) {
+  PluginConfigFactory(@GerritServerConfig Config cfg,
+      ProjectCache projectCache, ProjectState.Factory projectStateFactory) {
     this.cfg = cfg;
     this.projectCache = projectCache;
+    this.projectStateFactory = projectStateFactory;
   }
 
   public PluginConfig get(String pluginName) {
@@ -46,4 +49,9 @@ public class PluginConfigFactory {
     }
     return projectState.getConfig().getPluginConfig(pluginName);
   }
+
+  public PluginConfig getWithInheritance(Project.NameKey projectName,
+      String pluginName) throws NoSuchProjectException {
+    return get(projectName, pluginName).withInheritance(projectStateFactory);
+  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/git/ProjectConfig.java

@@ -707,7 +707,7 @@ public class ProjectConfig extends VersionedMetaData {
       pluginConfig = new Config();
       pluginConfigs.put(pluginName, pluginConfig);
     }
-    return new PluginConfig(pluginName, pluginConfig);
+    return new PluginConfig(pluginName, pluginConfig, this);
   }
 
   private Map<String, GroupReference> readGroupList() throws IOException {