/* -*- 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 Communicator client code, released
 * March 31, 1998.
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation. Portions created by Netscape are
 * Copyright (C) 1998-1999 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 */

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

interface nsIAllocator;
interface nsIInputStream;
interface nsIOutputStream;

/**
 * The nsIStorageStream interface maintains an internal data buffer that can be
 * filled using a single output stream.  One or more independent input streams
 * can be created to read the data from the buffer non-destructively.
 */

[scriptable, uuid(604ad9d0-753e-11d3-90ca-0040056a906e)]
interface nsIStorageStream : nsISupports
{
    /**
     * Get a reference to the one and only output stream for this instance.
     * The zero-based startPosition argument is used is used to set the initial
     * write cursor position.  The startPosition cannot be set larger than the
     * current buffer length.  Calling this method has the side-effect of
     * truncating the internal buffer to startPosition bytes.
     */
    nsIOutputStream getOutputStream(in PRInt32 startPosition);

    /**
     * Create a new input stream to read data (written by the singleton output
     * stream) from the internal buffer.  Multiple, independent input streams
     * can be created.
     */
    nsIInputStream newInputStream(in PRInt32 startPosition);

    /** 
     * The length attribute indicates the total number of bytes stored in the
     * nsIStorageStream internal buffer, regardless of any consumption by input
     * streams.  Assigning to the length field can be used to truncate the
     * buffer data, but can not be used when either the instance's output
     * stream is in use.
     *
     * @See #writeInProgress */
    attribute PRUint32 length;

    /**
     * True, when output stream has not yet been Close'ed
     */
    readonly attribute boolean writeInProgress;
};

%{C++
// Factory method
NS_COM nsresult
NS_NewStorageStream(PRUint32 segmentSize, PRUint32 maxSize, nsIStorageStream **result);
%}