/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is nsICacheSession.idl, released
 * February 23, 2001.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Gordon Sheridan <gordon@netscape.com>
 *   Patrick Beard   <beard@netscape.com>
 *   Darin Fisher    <darin@netscape.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsISupports.idl"
#include "nsICache.idl"

interface nsICacheEntryDescriptor;
interface nsICacheListener;

[scriptable, uuid(ae9e84b5-3e2d-457e-8fcd-5bbd2a8b832e)]
interface nsICacheSession : nsISupports
{
    /**
     * Expired entries will be doomed or evicted if this attribute is set to
     * true.  If false, expired entries will be returned (useful for offline-
     * mode and clients, such as HTTP, that can update the valid lifetime of
     * cached content).  This attribute defaults to true.
     */
    attribute PRBool doomEntriesIfExpired;

    /**
     * A cache session can only give out one descriptor with WRITE access
     * to a given cache entry at a time.  Until the client calls MarkValid on
     * its descriptor, other attempts to open the same cache entry will block.
     */

    /**
     * Synchronous cache access.  This returns a unique descriptor each
     * time it is called, even if the same key is specified.  When
     * called by multiple threads for write access, only one writable
     * descriptor will be granted.  If 'blockingMode' is set to false, it will
     * return NS_ERROR_CACHE_WAIT_FOR_VALIDATION rather than block when another
     * descriptor has been given WRITE access but hasn't validated the entry yet.
     */
    nsICacheEntryDescriptor openCacheEntry(in ACString          key,
                                           in nsCacheAccessMode accessRequested,
                                           in boolean           blockingMode);

    /**
     * Asynchronous cache access. Does not block the calling thread.
     * Instead, the listener will be notified when the descriptor is
     * available.
     */
    void asyncOpenCacheEntry(in ACString          key,
                             in nsCacheAccessMode accessRequested,
                             in nsICacheListener  listener);

    /**
     * Evict all entries for this session's clientID according to its storagePolicy.
     */
    void evictEntries();
    
    /**
     * Return whether any of the cache devices implied by the session storage policy
     * are currently enabled for instantiation if they don't already exist.
     */
    PRBool isStorageEnabled();
};