Move ajax request list into LiftSession with lastSeen.

LiftSession is in charge of managing cleanup of non-recently-seen pages
and such, so it needs to know about the AjaxRequestInfo list to clean it
up when a given request hasn't been needed in sufficiently long.

web/webkit/src/main/scala/net/liftweb/http/LiftServlet.scala

@@ -472,15 +472,7 @@ class LiftServlet extends Loggable {
 
   private case class AjaxResponseComplete(response: Box[LiftResponse])
 
-  /**
-   * existingResponse is Empty if we have no response for this request
-   * yet. pendingActors is a list of actors who want to be notified when
-   * this response is received.
-   */
-  private case class AjaxRequestInfo(requestVersion:Int, existingResponse:Box[Box[LiftResponse]], pendingActors:List[LiftActor])
-
   private lazy val ajaxPostTimeout: Long = LiftRules.ajaxPostTimeout * 1000L
-  private val currentAjaxRequests = scala.collection.mutable.Map[String,AjaxRequestInfo]()
 
   /**
    * Runs the actual AJAX processing. This includes handling __lift__GC,
@@ -510,9 +502,6 @@ class LiftServlet extends Loggable {
           val renderVersion = RenderVersion.get
           liftSession.updateFuncByOwner(renderVersion, millis)
 
-          // FIXME We need to clean up currentAjaxRequests entries when
-          // FIXME the page expires.
-
           Full(JavaScriptResponse(js.JsCmds.Noop))
 
         case _ =>
@@ -626,36 +615,36 @@ class LiftServlet extends Loggable {
         val renderVersion = RenderVersion.get
 
         val toReturn: Box[Box[LiftResponse]] =
-          currentAjaxRequests.synchronized {
+          liftSession.withAjaxRequests { currentAjaxRequests =>
             currentAjaxRequests.get(renderVersion).collect {
-              case AjaxRequestInfo(storedVersion, _, pendingActors) if handlerVersion != storedVersion =>
+              case AjaxRequestInfo(storedVersion, _, pendingActors, _) if handlerVersion != storedVersion =>
                 // Break out of any actors for the stale version.
                 pendingActors.foreach(_ ! BreakOut())
 
                 // Evict the older version's info.
                 currentAjaxRequests +=
                   (renderVersion ->
-                    AjaxRequestInfo(handlerVersion, Empty, cont :: Nil))
+                    AjaxRequestInfo(handlerVersion, Empty, cont :: Nil, millis))
 
                 suspendRequest()
 
                 Empty // no response available, triggers the actual AJAX computation below
 
-              case AjaxRequestInfo(storedVersion, existingResponseBox @ Full(_), _) =>
+              case AjaxRequestInfo(storedVersion, existingResponseBox @ Full(_), _, _) =>
                 existingResponseBox // return the Full response Box
 
-              case AjaxRequestInfo(storedVersion, _, pendingActors) =>
+              case AjaxRequestInfo(storedVersion, _, pendingActors, _) =>
                 currentAjaxRequests +=
                   (renderVersion ->
-                    AjaxRequestInfo(handlerVersion, Empty, cont :: pendingActors))
+                    AjaxRequestInfo(handlerVersion, Empty, cont :: pendingActors, millis))
 
                 suspendRequest()
 
                 Full(Full(EmptyResponse))
             } openOr {
               currentAjaxRequests +=
                 (renderVersion ->
-                  AjaxRequestInfo(handlerVersion, Empty, cont :: Nil))
+                  AjaxRequestInfo(handlerVersion, Empty, cont :: Nil, millis))
 
               suspendRequest()
 
@@ -670,13 +659,13 @@ class LiftServlet extends Loggable {
             // any waiting actors then clear the actor list and update the
             // request info to include the response in case any other
             // requests come in with this version.
-            currentAjaxRequests.synchronized {
+            liftSession.withAjaxRequests { currentAjaxRequests =>
               currentAjaxRequests.get(renderVersion).collect {
-                case AjaxRequestInfo(storedVersion, _, pendingActors) if storedVersion == handlerVersion =>
+                case AjaxRequestInfo(storedVersion, _, pendingActors, _) if storedVersion == handlerVersion =>
                   pendingActors.foreach(_ ! AjaxResponseComplete(Full(result)))
                   currentAjaxRequests +=
                     (renderVersion ->
-                      AjaxRequestInfo(handlerVersion, Full(Full(result)), Nil))
+                      AjaxRequestInfo(handlerVersion, Full(Full(result)), Nil, millis))
               }
             }
           })))

web/webkit/src/main/scala/net/liftweb/http/LiftSession.scala

@@ -499,6 +499,16 @@ private final case class PostPageFunctions(renderVersion: String,
 
 }
 
+/**
+ * existingResponse is Empty if we have no response for this request
+ * yet. pendingActors is a list of actors who want to be notified when
+ * this response is received.
+ */
+private[http] final case class AjaxRequestInfo(requestVersion:Int,
+                                               existingResponse:Box[Box[LiftResponse]],
+                                               pendingActors:List[LiftActor],
+                                               lastSeen: Long)
+
 /**
  * The LiftSession class containg the session state information
  */
@@ -557,6 +567,16 @@ class LiftSession(private[http] val _contextPath: String, val uniqueId: String,
    */
   private var postPageFunctions: Map[String, PostPageFunctions] = Map()
 
+  /**
+   * A list of AJAX requests that may or may not be pending for this
+   * session. There is up to one entry per RenderVersion.
+   */
+  private var ajaxRequests = scala.collection.mutable.Map[String,AjaxRequestInfo]()
+
+  private[http] def withAjaxRequests[T](fn: (scala.collection.mutable.Map[String, AjaxRequestInfo]) => T) = {
+    ajaxRequests.synchronized { fn(ajaxRequests) }
+  }
+
   /**
    * The synchronization lock for the postPageFunctions
    */
@@ -850,6 +870,15 @@ class LiftSession(private[http] val _contextPath: String, val uniqueId: String,
         }
       }
 
+      withAjaxRequests { currentAjaxRequests =>
+        for {
+          (version, requestInfo) <- currentAjaxRequests
+            if (now - requestInfo.lastSeen) > LiftRules.unusedFunctionsLifeTime
+        } {
+          currentAjaxRequests -= version
+        }
+      }
+
       synchronized {
         messageCallback.foreach {
           case (k, f) =>
@@ -977,6 +1006,13 @@ class LiftSession(private[http] val _contextPath: String, val uniqueId: String,
       } postPageFunctions += (ownerName -> funcInfo.updateLastSeen)
     }
 
+    withAjaxRequests { currentAjaxRequests =>
+      currentAjaxRequests.get(ownerName).foreach {
+        case info: AjaxRequestInfo =>
+          currentAjaxRequests += (ownerName -> info.copy(lastSeen = time))
+      }
+    }
+
     synchronized {
       (0 /: messageCallback)((l, v) => l + (v._2.owner match {
         case Full(owner) if (owner == ownerName) =>