src/Pure/Thy/thy_resources.scala

 
 PIDE resources for theory files: load/unload theories via PIDE document updates.
 */
 
 package isabelle
+
+
+import java.io.{File => JFile}
 
 
 object Thy_Resources
 {
   /* PIDE session */

   class Session private[Thy_Resources](
     session_options: Options,
     override val resources: Thy_Resources) extends isabelle.Session(session_options, resources)
   {
     session =>
+
+    val tmp_dir: JFile = Isabelle_System.tmp_dir("server_session")
+
+    override def stop(): Process_Result =
+    {
+      try { super.stop() }
+      finally { Isabelle_System.rm_tree(tmp_dir) }
+    }
 
     def use_theories(
       theories: List[(String, Position.T)],
       qualifier: String = Sessions.DRAFT,
       master_dir: String = "",