source: vbox/trunk/src/libs/xpcom18a4/xpcom/io/nsIFastLoadFileControl.idl@ 4837

/* -*- Mode: C++; 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 Mozilla FastLoad code.
 *
 * 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):
 *   Brendan Eich <brendan@mozilla.org> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of 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 "nsrootidl.idl"

interface nsIFile;
interface nsISimpleEnumerator;

/**
 * The nsIFastLoadFileControl interface and its subinterfaces are mix-ins for
 * classes implementing nsIObjectInputStream and nsIObjectOutputStream, so that
 * those stream types can be used with nsIFastLoadService to access and compute
 * FastLoad file checksums, update and check FastLoad file dependencies, and
 * multiplex documents loaded via non-blocking i/o.
 *
 * If an nsIObjectInputStream class doesn't support nsIFastLoadReadControl, or
 * an nsIObjectOutputStream class doesn't support nsIFastLoadWriteControl, that
 * implementation may still be useful for object serialization, but it can't be
 * used to read or write a Mozilla FastLoad file.
 */
[scriptable, uuid(8a1e2c63-af50-4147-af7e-26289dc180dd)]
interface nsIFastLoadFileControl : nsISupports
{
    /**
     * Get and set the recorded checksum value from the FastLoad file header.
     */
    attribute PRUint32 checksum;

    /**
     * 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.
     *
     * Note: Select returns the previously selected URI object in case the
     * caller is synchronously selecting and writing data to the FastLoad
     * file, so the caller can reselect the previous URI and return to code
     * the continues to write FastLoad data for the previous URI, unaware of
     * the nested select/write/reselect.
     */
    void        startMuxedDocument(in nsISupports aURI, in string aURISpec);
    nsISupports selectMuxedDocument(in nsISupports aURI);
    void        endMuxedDocument(in nsISupports aURI);

    /**
     * Return true if aURISpec identifies a muxed document in the FastLoad
     * file, false otherwise.
     */
    boolean     hasMuxedDocument(in string aURISpec);
};

[scriptable, uuid(652ecec6-d40b-45b6-afef-641d6c63a35b)]
interface nsIFastLoadReadControl : nsIFastLoadFileControl
{
    /**
     * Computes the correct checksum of the FastLoad file, independent of the
     * header's checksum value.  The header checksum field is treated as zero
     * when computing the 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 nsISimpleEnumerator dependencies;
};

[scriptable, uuid(2ad6e9e6-1379-4e45-a899-a54b27ff915c)]
interface nsIFastLoadWriteControl : nsIFastLoadFileControl
{
    /**
     * Add a file dependency of the FastLoad file (e.g., a .jar file) to the
     * set of dependencies that trigger regeneration if any dependency has a
     * last-modified-time greater than the FastLoad file's mtime.
     */
    void addDependency(in nsIFile aFile);
};