diff -r 000000000000 -r 6474c204b198 docshell/shistory/src/nsSHistory.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docshell/shistory/src/nsSHistory.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,121 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsSHistory_h
+#define nsSHistory_h
+
+// Helper Classes
+#include "nsCOMPtr.h"
+
+//Interfaces Needed
+#include "nsISHistory.h"
+#include "nsISHistoryInternal.h"
+#include "nsIWebNavigation.h"
+#include "nsISimpleEnumerator.h"
+#include "nsTObserverArray.h"
+#include "nsWeakPtr.h"
+
+// Needed to maintain global list of all SHistory objects
+#include "prclist.h"
+
+class nsIDocShell;
+class nsSHEnumerator;
+class nsSHistoryObserver;
+class nsISHEntry;
+class nsISHTransaction;
+
+class nsSHistory: public PRCList,
+                  public nsISHistory,
+                  public nsISHistoryInternal,
+                  public nsIWebNavigation
+{
+public:
+  nsSHistory();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISHISTORY
+  NS_DECL_NSISHISTORYINTERNAL
+  NS_DECL_NSIWEBNAVIGATION
+
+  // One time initialization method called upon docshell module construction
+  static nsresult Startup();
+  static void Shutdown();
+  static void UpdatePrefs();
+
+  // Max number of total cached content viewers.  If the pref
+  // browser.sessionhistory.max_total_viewers is negative, then
+  // this value is calculated based on the total amount of memory.
+  // Otherwise, it comes straight from the pref.
+  static uint32_t GetMaxTotalViewers() { return sHistoryMaxTotalViewers; }
+
+protected:
+  virtual ~nsSHistory();
+  friend class nsSHEnumerator;
+  friend class nsSHistoryObserver;
+
+   // Could become part of nsIWebNavigation
+   NS_IMETHOD GetTransactionAtIndex(int32_t aIndex, nsISHTransaction ** aResult);
+   nsresult CompareFrames(nsISHEntry * prevEntry, nsISHEntry * nextEntry, nsIDocShell * rootDocShell, long aLoadType, bool * aIsFrameFound);
+   nsresult InitiateLoad(nsISHEntry * aFrameEntry, nsIDocShell * aFrameDS, long aLoadType);
+
+   NS_IMETHOD LoadEntry(int32_t aIndex, long aLoadType, uint32_t histCmd);
+
+#ifdef DEBUG
+   nsresult PrintHistory();
+#endif
+
+  // Evict content viewers in this window which don't lie in the "safe" range
+  // around aIndex.
+  void EvictOutOfRangeWindowContentViewers(int32_t aIndex);
+  static void GloballyEvictContentViewers();
+  static void GloballyEvictAllContentViewers();
+
+  // Calculates a max number of total
+  // content viewers to cache, based on amount of total memory
+  static uint32_t CalcMaxTotalViewers();
+
+  void RemoveDynEntries(int32_t aOldIndex, int32_t aNewIndex);
+
+  nsresult LoadNextPossibleEntry(int32_t aNewIndex, long aLoadType, uint32_t aHistCmd);
+protected:
+  // aIndex is the index of the transaction which may be removed.
+  // If aKeepNext is true, aIndex is compared to aIndex + 1,
+  // otherwise comparison is done to aIndex - 1.
+  bool RemoveDuplicate(int32_t aIndex, bool aKeepNext);
+
+  nsCOMPtr<nsISHTransaction> mListRoot;
+  int32_t mIndex;
+  int32_t mLength;
+  int32_t mRequestedIndex;
+  // Session History listeners
+  nsAutoTObserverArray<nsWeakPtr, 2> mListeners;
+  // Weak reference. Do not refcount this.
+  nsIDocShell *  mRootDocShell;
+
+  // Max viewers allowed total, across all SHistory objects
+  static int32_t  sHistoryMaxTotalViewers;
+};
+//*****************************************************************************
+//***    nsSHEnumerator: Object Management
+//*****************************************************************************
+class nsSHEnumerator : public nsISimpleEnumerator
+{
+public:
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISIMPLEENUMERATOR
+
+  nsSHEnumerator(nsSHistory *  aHistory);
+  
+protected:
+  friend class nsSHistory;
+  virtual ~nsSHEnumerator();
+private:
+  int32_t     mIndex;
+  nsSHistory *  mSHistory;  
+};
+
+#endif   /* nsSHistory */