Fix for bug # 100993. Freeze nsIHistoryEntry.idl and nsISHistory.idl according to the

embedding freezing guidelines. r=chak sr=alec

docshell/shistory/public/nsIHistoryEntry.idl

@@ -37,28 +37,45 @@
  * ***** END LICENSE BLOCK ***** */
 
 /**
- * The interface to nsIHistoryEntry. Each document or subframe in 
- * Session History will have a nsIHistoryEntry associated with it which will
- * hold only public information like URI and title for that document.
- * More information like post data layout data are held in the private 
- * interface nsISHEntry
+ * An interface to individual entries in session history. Each 
+ * document or frame will have a nsIHistoryEntry associated with 
+ * it. nsIHistoryEntry provides access to information like URI, 
+ * title and frame traversal status for that document.
+ * This interface is accessible from javascript.
+ * 
  * @status FROZEN
- * @version 1.0
  */
 #include "nsISupports.idl"
-#include "nsIURI.idl"
+
+interface nsIURI;
 
 [scriptable, uuid(A41661D4-1417-11D5-9882-00C04FA02F40)]
 interface nsIHistoryEntry : nsISupports 
 {
 
-/** URI for the document */
+/** 
+ * A readonly property that returns the URI
+ * of the current entry. The object returned is
+ * of type nsIURI
+ */
 readonly attribute nsIURI URI;
 
-/** Title for the document */
+/** 
+ * A readonly property that returns the title
+ * of the current entry.  The object returned
+ * is a encoded string
+ */
 readonly attribute wstring title;
 
-/** Flag that indicates if the entry is for a subframe navigation */
+/** 
+ * A readonly property that returns a boolean
+ * flag which indicates if the entry was created as a 
+ * result of a subframe navigation. This flag will be
+ * 'false' when a frameset page is visited for
+ * the first time. This flag will be 'true' for all
+ * history entries created as a result of a subframe
+ * navigation.
+ */
 readonly attribute boolean isSubFrame;
 
 };

docshell/shistory/public/nsISHistory.idl

@@ -36,18 +36,24 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
+#include "nsISupports.idl"
+
+interface nsIHistoryEntry;
+interface nsISHistoryListener;
+interface nsISimpleEnumerator;
 /**
- * Interface to Session History
+ * An interface to the primary properties of the Session History
+ * component. In an embedded browser environment, the nsIWebBrowser
+ * object creates an instance of session history for each open window.
+ * A handle to the session history object can be obtained from
+ * nsIWebNavigation. In a non-embedded situation, the  owner of the
+ * session history component must create a instance of it and set
+ * it in the nsIWebNavigation object.
+ * This interface is accessible from javascript. 
  *
  * @status FROZEN
  */
  
-#include "nsISupports.idl"
-#include "nsIFactory.idl"
-#include "nsIHistoryEntry.idl"
-#include "nsISHistoryListener.idl"
-
-interface nsISimpleEnumerator;
 
 %{C++
 #define NS_SHISTORY_CID \
@@ -60,43 +66,109 @@ interface nsISimpleEnumerator;
 interface nsISHistory: nsISupports
 {
   /**
-   * Get the size of the History list
+   * A readonly property of the interface that returns 
+   * the number of toplevel documents currently available
+   * in session history.
    */
    readonly attribute long count;
 
   /**
-   * Get the index of the current document in the history list
+   * A readonly property of the interface that returns 
+   * the index of the current document in session history.
    */
    readonly attribute long index;
 
   /**
-   * Get/Set the Max entries Session History will hold per window
+   * A read/write property of the interface, used to Get/Set
+   * the maximum number of toplevel documents, session history 
+   * can hold for each instance. 
    */
    attribute long maxLength;
 
   /**
-   * Get the entry at a given index
+   * Called to obtain handle to the history entry at a
+   * given index.
+   *
+   * @param index             The index value whose entry is requested.
+   * @param modifyIndex       A boolean flag that indicates if the current
+   *                          index of session history should be modified 
+   *                          to the parameter index.
+   *
+   * @return                  <code>NS_OK</code> history entry for 
+   *                          the index is obtained successfully.
+   *                          <code>NS_ERROR_FAILURE</code> Error in obtaining
+   *                          history entry for the given index.
    */
    nsIHistoryEntry getEntryAtIndex(in long index, in boolean modifyIndex);
 
 
   /**
-   * Purge the oldest numEntries from history list
+   * Called to purge older documents from history.
+   * Documents can be removed from session history for various 
+   * reasons. For example to  control memory usage of the browser, to 
+   * prevent users from loading documents from history, to erase evidence of
+   * prior page loads etc...
+   *
+   * @param numEntries        The number of toplevel documents to be
+   *                          purged from history. During purge operation,
+   *                          the latest documents are maintained and older 
+   *                          'numEntries' documents are removed from history.
+   * @return                  <code>NS_OK</code> Purging was successfull
+   *                          <code>NS_ERROR_FAILURE</code> numEntries is
+   *                          invalid or out of bounds with the size of history.
+   *                          
    */
    void PurgeHistory(in long numEntries);
 
   /**
-   * Register a Session History Listener to be notified on SHistory events
+   * Called to register a listener for the session history component.
+   * Listeners are notified when pages are loaded or purged from history.
+   * 
+   * @param aListener         Listener object to be notified for all
+   *                          page loads that initiate in session history.
+   *
+   * @note                    A listener object must implement 
+   *                          nsISHistoryListener and nsSupportsWeakReference
+   *
+   * @see nsISHistoryListener
+   * @see nsSupportsWeakReference
    */
    void addSHistoryListener(in nsISHistoryListener aListener);
 
   /**
-   * Remove a previously registered Session History Listener 
-   */
+   * Called to remove a listener for the session history component.
+   * Listeners are notified when pages are loaded from history.
+   * 
+   * @param aListener         Listener object to be removed from 
+   *                          session history.
+   *
+   * @note                    A listener object must implement 
+   *                          nsISHistoryListener and nsSupportsWeakReference
+   * @see nsISHistoryListener
+   * @see nsSupportsWeakReference
+   */ 
    void removeSHistoryListener(in nsISHistoryListener aListener);
 
   /**
-   * Get a enumerator to access all the entries in SH
+   * Called to obtain a enumerator for all the  documents stored in 
+   * session history. The enumerator object thus returned by this method
+   * can be traversed using nsISimpleEnumerator. 
+   *
+   * @note  To access individual history entries of the enumerator, perform the
+   *        following steps:
+   *        1) Call nsISHistory->GetSHistoryEnumerator() to obtain handle 
+   *           the nsISimpleEnumerator object.
+   *        2) Use nsISimpleEnumerator->GetNext() on the object returned
+   *           by step #1 to obtain handle to the next object in the list. 
+   *           The object returned by this step is of type nsISupports.
+   *        3) Perform a QueryInterface on the object returned by step #2 
+   *           to nsIHistoryEntry.
+   *        4) Use nsIHistoryEntry to access properties of each history entry. 
+   *
+   * @see nsISimpleEnumerator
+   * @see nsIHistoryEntry
+   * @see QueryInterface()
+   * @see do_QueryInterface()
    */
    readonly attribute nsISimpleEnumerator SHistoryEnumerator;
 };

docshell/shistory/src/nsSHistory.cpp

@@ -410,8 +410,14 @@ nsSHistory::AddSHistoryListener(nsISHistoryListener * aListener)
 NS_IMETHODIMP
 nsSHistory::RemoveSHistoryListener(nsISHistoryListener * aListener)
 {
-  mListener = nsnull;
-  return NS_OK;
+  // Make sure the listener that wants to be removed is the
+  // one we have in store. 
+  nsWeakPtr listener = getter_AddRefs(NS_GetWeakReference(aListener));  
+  if (listener == mListener) {
+    mListener = nsnull;
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
 }
 
 //*****************************************************************************

docshell/shistory/src/nsSHistory.h

@@ -33,6 +33,8 @@
 #include "nsIWebNavigation.h"
 #include "nsIWeakReference.h"
 #include "nsISimpleEnumerator.h"
+#include "nsISHistoryListener.h"
+#include "nsIHistoryEntry.h"
 
 class nsIDocShell;
 class nsSHEnumerator;