PrerenderTracker Cleanup

chrome/browser/prerender/prerender_tracker.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PRERENDER_PRERENDER_TRACKER_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_TRACKER_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 10 matching lines @@
 // PrerenderTracker is responsible for keeping track of all prerendering
 // RenderViews and their statuses.  Its list is guaranteed to be up to date
 // and can be modified on any thread.
 class PrerenderTracker {
  public:
   // Returns the PrerenderTracker singleton.
   static PrerenderTracker* GetInstance();
 
   // Attempts to set the status of the specified RenderViewHost to
   // FINAL_STATUS_USED.  Returns true on success.  Returns false if it has
-  // already been cancelled for any reason, or is no longer prerendering.
+  // already been cancelled for any reason or is no longer prerendering.
   // Can only be called only on the IO thread.  This method will not call
   // PrerenderContents::set_final_status() on the corresponding
   // PrerenderContents.
   //
-  // If it returns true, all subsequent calls to TryCancel for the RenderView
-  // will return false.
+  // If it returns true, all subsequent calls to TryCancel and TryUse for the
+  // RenderView will return false.
   bool TryUse(int child_id, int route_id);
 
   // Attempts to cancel prerendering by the specified RenderView, setting the
   // FinalStatus to |final_status|.  Returns true if the specified prerender has
   // been cancelled, either as a result of this call or for any other reason.
   // If the call results in cancelling a PrerenderContents, a task to destroy
   // it is also posted to the UI thread.
   //
   // When true is returned, it is guaranteed that the RenderView will never
   // be displayed.  When false is returned, the RenderView has either been
@@ skipping 10 matching lines @@
   // been displayed or destroyed is still prerendering.
   // TODO(mmenke):  Remove external use of this method and make it private.
   bool IsPrerenderingOnIOThread(int child_id, int route_id) const;
 
   // Gets the FinalStatus of the specified prerendered RenderView.  Returns
   // |true| and sets |final_status| to the status of the RenderView if it
   // is found, returns false otherwise.
   bool GetFinalStatus(int child_id, int route_id,
                       FinalStatus* final_status) const;
 
- protected:
+ private:
+  friend struct DefaultSingletonTraits<PrerenderTracker>;
   friend class PrerenderContents;
 
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerUsed);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerCancelled);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerCancelledOnIO);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerCancelledFast);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerMultiple);
 
+  typedef std::pair<int, int> ChildRouteIdPair;
+
+  // Map of child/route id pairs to final statuses.
+  typedef std::map<ChildRouteIdPair, RenderViewInfo> FinalStatusMap;
+  // Set of child/route id pairs that may be prerendering.
+  typedef std::set<ChildRouteIdPair> PossiblyPrerenderingChildRouteIdPairs;
+
+  PrerenderTracker();
+  ~PrerenderTracker();
+
   // Must be called when a RenderView starts prerendering, before the first
   // navigation starts to avoid any races.
   void OnPrerenderingStarted(int child_id, int route_id,
                              PrerenderManager* prerender_manager);
 
   // Must be called when a RenderView stops prerendering, either because the
   // RenderView was used or prerendering was cancelled and it is being
   // destroyed.
   void OnPrerenderingFinished(int child_id, int route_id);
 
- private:
-  friend struct DefaultSingletonTraits<PrerenderTracker>;
-
-  typedef std::pair<int, int> ChildRouteIdPair;
-
-  // Map of child/route id pairs to final statuses.
-  typedef std::map<ChildRouteIdPair, RenderViewInfo> FinalStatusMap;
-  // Set of child/route id pairs that may be prerendering.
-  typedef std::set<ChildRouteIdPair> PossiblyPrerenderingChildRouteIdPairs;
-
-  PrerenderTracker();
-  ~PrerenderTracker();
-
   // Attempts to set the FinalStatus of the specified RenderView to
-  // |final_status|.  If the FinalStatus of the RenderView has already been
-  // set, does nothing.  Returns the resulting FinalStatus of that RenderView,
-  // regardless of success or failure.  If the RenderView isn't currently
-  // prerendering, returns FINAL_STATUS_MAX.
-  FinalStatus SetFinalStatus(int child_id, int route_id,
-                             FinalStatus final_status);
+  // |desired_final_status|.  If non-NULL, |actual_final_status| is set to the
+  // FinalStatus of the RenderView.
+  //
+  // If the FinalStatus of the RenderView is successfully set, returns true and
+  // sets |actual_final_status| to |desired_final_status|.
+  //
+  // If the FinalStatus of the RenderView was already set, returns false and
+  // sets |actual_final_status| to the actual FinalStatus of the RenderView.
+  //
+  // If the RenderView is not a prerendering RenderView, returns false and sets
+  // |actual_final_status| to FINAL_STATUS_MAX.
+  bool SetFinalStatus(int child_id, int route_id,
+                      FinalStatus desired_final_status,
+                      FinalStatus* actual_final_status);
 
   // Add/remove the specified pair to |possibly_prerendering_io_thread_set_| on
   // the IO Thread.
   void AddPrerenderOnIOThread(const ChildRouteIdPair& child_route_id_pair);
   void RemovePrerenderOnIOThread(const ChildRouteIdPair& child_route_id_pair);
 
   // Tasks posted to the IO Thread to call the above functions.
   static void AddPrerenderOnIOThreadTask(
       const ChildRouteIdPair& child_route_id_pair);
   static void RemovePrerenderOnIOThreadTask(
@@ skipping 10 matching lines @@
   // the IO thread.  May contain entries that have since been displayed.  Only
   // used to prevent locking when not needed.
   PossiblyPrerenderingChildRouteIdPairs possibly_prerendering_io_thread_set_;
 
   DISALLOW_COPY_AND_ASSIGN(PrerenderTracker);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_TRACKER_H_