Added the concept of a replaceable entry. This is an entry which when a new item is added will get overwritten rather than adding the entry to the end of the list.

docshell/shistory/public/nsISHTransaction.idl

@@ -36,7 +36,7 @@ interface nsISHTransaction : nsISupports
 	/**
      * The nsISHEntry for the current transaction
      */
-	readonly attribute nsISHEntry sHEntry;
+	attribute nsISHEntry sHEntry;
 
 	/**
 	 * The parent of this transaction
@@ -53,6 +53,12 @@ interface nsISHTransaction : nsISupports
 	 */
 	readonly attribute nsISHTransaction lrvList;
 
+	/**
+	 *	Specifies if this transaction should persist.  If not it will be replaced
+	 * by new additions to the list.
+	 */
+	attribute boolean persist;
+
 	/**
 	 * Create a transaction with parent and History Entry 
 	 */

docshell/shistory/public/nsISHistory.idl

@@ -38,8 +38,12 @@ interface nsISHistory: nsISupports
 {
   /**
    * Add a new Entry to the History List
+	* @param aEntry - The entry to add
+	* @param aPersist - If true this specifies that the entry should persist
+	* in the list.  If false, this means that when new entries are added
+	* this element will not appear in the session history list.
    */
-   void  addEntry(in nsISHEntry aEntry);
+   void  addEntry(in nsISHEntry aEntry, in boolean aPersist);
 
   /**
    * Get the size of the History list

docshell/shistory/src/nsSHTransaction.cpp

@@ -40,7 +40,8 @@
 
 NS_IMPL_ISUPPORTS1(nsSHTransaction, nsISHTransaction)
 
-nsSHTransaction::nsSHTransaction() : mParent(nsnull), mChild(nsnull),mLRVList(nsnull), mSHEntry(nsnull)
+nsSHTransaction::nsSHTransaction() : mPersist(PR_TRUE), mParent(nsnull), 
+   mChild(nsnull), mLRVList(nsnull), mSHEntry(nsnull)
 {
 NS_INIT_REFCNT();
 }
@@ -157,6 +158,22 @@ nsSHTransaction::GetLrvList(nsISHTransaction ** aResult)
    return NS_OK;
 }
 
+NS_IMETHODIMP
+nsSHTransaction::SetPersist(PRBool aPersist)
+{
+   mPersist = aPersist;
+   return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSHTransaction::GetPersist(PRBool* aPersist)
+{
+   NS_ENSURE_ARG_POINTER(aPersist);
+
+   *aPersist = mPersist;
+   return NS_OK;
+}
+
 
 NS_IMETHODIMP
 NS_NewSHTransaction(nsISupports* aOuter, REFNSIID aIID, void** aResult)

docshell/shistory/src/nsSHTransaction.h

@@ -43,9 +43,11 @@ private:
 		NS_NewSHTransaction(nsISupports * aOuter, REFNSIID aIID, void** aResult);
 	nsresult SetChild(nsISHTransaction * aChild);
 	nsresult SetParent(nsISHTransaction * aParent);
-	nsresult SetSHEntry(nsISHEntry * aSHEntry);
+	//nsresult SetSHEntry(nsISHEntry * aSHEntry);
 	//nsresult SetLRVList(nsISHTransaction * aLRVList);
     
+   PRBool         mPersist;
+
 	/* Weak reference to parent */
 	nsISHTransaction * mParent;
 	nsISHTransaction * mChild;

docshell/shistory/src/nsSHistory.cpp

@@ -57,37 +57,41 @@ nsSHistory::~nsSHistory()
  * increment the index to point to the new entry
  */
 NS_IMETHODIMP
-nsSHistory::AddEntry(nsISHEntry * aSHEntry)
+nsSHistory::AddEntry(nsISHEntry * aSHEntry, PRBool aPersist)
 {
-	nsresult rv;
+   NS_ENSURE_ARG(aSHEntry);
 
-	NS_PRECONDITION(aSHEntry != nsnull, "null ptr");
-    if (! aSHEntry)
-      return NS_ERROR_NULL_POINTER;
+   nsCOMPtr<nsISHTransaction> currentTxn;
 
-	nsCOMPtr<nsISHTransaction>  txn;
-    rv = nsComponentManager::CreateInstance(NS_SHTRANSACTION_PROGID,
-	                                      nsnull,
-										  NS_GET_IID(nsISHTransaction),
-										  getter_AddRefs(txn));
-	nsCOMPtr<nsISHTransaction> parent;
+   if(mListRoot)
+      GetTransactionAtIndex(mIndex, getter_AddRefs(currentTxn));
+
+   PRBool currentPersist = PR_TRUE;
+   if(currentTxn)
+      currentTxn->GetPersist(&currentPersist);
+
+   if(!currentPersist)
+      {
+      NS_ENSURE_SUCCESS(currentTxn->SetSHEntry(aSHEntry),
+         NS_ERROR_FAILURE);
+      return NS_OK;
+      }
+
+	nsCOMPtr<nsISHTransaction> txn(do_CreateInstance(NS_SHTRANSACTION_PROGID));
+   NS_ENSURE_TRUE(txn, NS_ERROR_FAILURE);
+
+   // Set the ShEntry and parent for the transaction. setting the 
+	// parent will properly set the parent child relationship
+   txn->SetPersist(aPersist);
+	NS_ENSURE_SUCCESS(txn->Create(aSHEntry, currentTxn), NS_ERROR_FAILURE);
+   
+   mLength++;
+   mIndex++;
+   // If this is the very first transaction, initialize the list
+   if(!mListRoot)
+      mListRoot = txn;
+   PrintHistory();
 
-    if (NS_SUCCEEDED(rv) && txn) {		
-		if (mListRoot) {
-           GetTransactionAtIndex(mIndex, getter_AddRefs(parent));
-		}
-		// Set the ShEntry and parent for the transaction. setting the 
-		// parent will properly set the parent child relationship
-		rv = txn->Create(aSHEntry, parent);
-		if (NS_SUCCEEDED(rv)) {
-            mLength++;
-			mIndex++;
-		    // If this is the very first transaction, initialize the list
-		    if (!mListRoot)
-			   mListRoot = txn;
-                      PrintHistory();
-		}
-	}
    return NS_OK;
 }