(refs #32)Add plugin system initialization

src/main/scala/plugin/JavaScriptPlugin.scala

@@ -71,7 +71,7 @@ object JavaScriptPlugin {
     val context = JsContext.enter()
     try {
       val scope = context.initStandardObjects()
-      scope.put("PluginSystem", scope, this)
+      scope.put("PluginSystem", scope, PluginSystem)
       scope.put("JavaScriptPlugin", scope, this)
       val result = context.evaluateString(scope, script, "<cmd>", 1, null)
       result

src/main/scala/plugin/PluginSystem.scala

@@ -3,6 +3,9 @@ package plugin
 import app.Context
 import javax.servlet.http.{HttpServletResponse, HttpServletRequest}
 import org.slf4j.LoggerFactory
+import java.util.concurrent.atomic.AtomicBoolean
+import util.Directory._
+import org.apache.commons.io.FileUtils
 
 /**
  * Provides extension points to plug-ins.
@@ -11,6 +14,7 @@ object PluginSystem {
 
   private val logger = LoggerFactory.getLogger(PluginSystem.getClass)
 
+  private val initialized = new AtomicBoolean(false)
   private val pluginsMap = scala.collection.mutable.Map[String, Plugin]()
 
   def install(plugin: Plugin): Unit = {
@@ -23,6 +27,28 @@ object PluginSystem {
     pluginsMap.remove(id)
   }
 
+  /**
+   * Initializes the plugin system. Load scripts from GITBUCKET_HOME/plugins.
+   */
+  def init(): Unit = {
+    if(initialized.compareAndSet(false, true)){
+      val pluginDir = new java.io.File(PluginHome)
+      if(pluginDir.exists && pluginDir.isDirectory){
+        pluginDir.listFiles.filter(f => f.isDirectory && !f.getName.startsWith(".")).foreach { dir =>
+          val file = new java.io.File(dir, "plugin.js")
+          if(file.exists && file.isFile){
+            val script = FileUtils.readFileToString(file, "UTF-8")
+            try {
+              JavaScriptPlugin.evaluateJavaScript(script)
+            } catch {
+              case e: Exception => logger.warn(s"Error in plugin loading for ${file.getAbsolutePath}", e)
+            }
+          }
+        }
+      }
+    }
+  }
+
   def repositoryMenus   : List[RepositoryMenu] = pluginsMap.values.flatMap(_.repositoryMenus).toList
   def globalMenus       : List[GlobalMenu]     = pluginsMap.values.flatMap(_.globalMenus).toList
   def repositoryActions : List[Action]         = pluginsMap.values.flatMap(_.repositoryActions).toList

src/main/scala/plugin/ScalaPlugin.scala

@@ -0,0 +1,37 @@
+package plugin
+
+import app.Context
+import scala.collection.mutable.ListBuffer
+import plugin.PluginSystem.{Action, GlobalMenu, RepositoryMenu}
+import javax.servlet.http.{HttpServletResponse, HttpServletRequest}
+
+// TODO This is a sample implementation for Scala based plug-ins.
+class ScalaPlugin(val id: String, val author: String, val url: String, val description: String) extends Plugin {
+
+  private val repositoryMenuList   = ListBuffer[RepositoryMenu]()
+  private val globalMenuList       = ListBuffer[GlobalMenu]()
+  private val repositoryActionList = ListBuffer[Action]()
+  private val globalActionList     = ListBuffer[Action]()
+
+  def repositoryMenus   : List[RepositoryMenu] = repositoryMenuList.toList
+  def globalMenus       : List[GlobalMenu]     = globalMenuList.toList
+  def repositoryActions : List[Action]         = repositoryActionList.toList
+  def globalActions     : List[Action]         = globalActionList.toList
+
+  def addRepositoryMenu(label: String, name: String, url: String, icon: String)(condition: (Context) => Boolean): Unit = {
+    repositoryMenuList += RepositoryMenu(label, name, url, icon, condition)
+  }
+
+  def addGlobalMenu(label: String, url: String, icon: String)(condition: (Context) => Boolean): Unit = {
+    globalMenuList += GlobalMenu(label, url, icon, condition)
+  }
+
+  def addGlobalAction(path: String)(function: (HttpServletRequest, HttpServletResponse) => Any): Unit = {
+    globalActionList += Action(path, function)
+  }
+
+  def addRepositoryAction(path: String)(function: (HttpServletRequest, HttpServletResponse) => Any): Unit = {
+    repositoryActionList += Action(path, function)
+  }
+
+}

src/main/scala/servlet/AutoUpdateListener.scala

@@ -178,6 +178,10 @@ class AutoUpdateListener extends ServletContextListener {
       }
     }
     logger.debug("End schema update")
+
+    logger.debug("Starting plugin system...")
+    plugin.PluginSystem.init()
+    logger.debug("Plugin system is initialized.")
   }
 
   def contextDestroyed(sce: ServletContextEvent): Unit = {

src/main/scala/util/Directory.scala

@@ -34,6 +34,8 @@ object Directory {
 
   val DatabaseHome = s"${GitBucketHome}/data"
 
+  val PluginHome = s"${GitBucketHome}/plugins"
+
   /**
    * Substance directory of the repository.
    */