gecko-dev/xpcom/io/nsIFastLoadFileControl.idl

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * The contents of this file are subject to the Netscape 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/NPL/
 *  
 * 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 Mozilla FastLoad code.
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation. Portions created by Netscape are
 * Copyright (C) 2001 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s):
 *   Brendan Eich <brendan@mozilla.org> (original author)
 */

#include "nsISupports.idl"
#include "nsrootidl.idl"

interface nsICollection;

/**
 * The nsIFastLoadFileControl interface is used as an extension to classes
 * implementing nsIObjectInputStream or nsIObjectOutputStream, so that those
 * stream types can be used with nsIFastLoadService to get, set, and compute
 * FastLoad file checksums, update and check FastLoad file dependencies, and
 * multiplex documents loaded via non-blocking i/o.
 *
 * If an nsIObjectInputStream or nsIObjectOutputStream implementation doesn't
 * implement nsIFastLoadFileControl, that implementation may still be useful
 * for object serialization, but it cannot be used to read or write a Mozilla
 * FastLoad file.
 */
[scriptable, uuid(8a1e2c63-af50-4147-af7e-26289dc180dd)]
interface nsIFastLoadFileControl : nsISupports
{
    /**
     * Get, set, and compute the FastLoad file checksum.  The attribute gets
     * and sets the recorded checksum value from the FastLoad file header,
     * while the method computes the correct checksum of the implementation's
     * underlying FastLoad file, independent of the header's checksum value
     * (which is treated as zero when computing the checksum).
     */
    attribute PRUint32 checksum;
    PRUint32 computeChecksum();

    /**
     * Get the collection of dependency nsIFile instances recorded during the
     * FastLoad file write or read/update process, and checked during the read
     * process to invalidate the FastLoad file if any dependencies are newer.
     */
    readonly attribute nsICollection dependencies;

    /**
     * Multiplexed document control methods.  A FastLoad file may contain
     * multiple interleaved documents identified by a URI specifier string,
     * and indexed for fast multiplexor select by an opaque URI object key.
     * You StartMuxedDocument when initiating a document load, then Select
     * before every batch of calls to (de)serialize document data, and End
     * when the load completes.
     *
     * Document multiplexing is necessary to support incremental FastLoad
     * development in a non-blocking i/o architecture such as Mozilla, where
     * some (but not all, at first, or for a while during development) of the
     * results of parsing and compiling various inputs can be multiplexed to
     * or from a FastLoad file.
     */
    void startMuxedDocument(in nsISupports aURI, in string aURISpec);
    void selectMuxedDocument(in nsISupports aURI);
    void endMuxedDocument(in nsISupports aURI);
};