mozilla-history/xpcom/io/nsIStorageStream.idl

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/* -*- 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 Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998-1999
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* 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 nsIMemory;
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-34278643278f)]
interface nsIStorageStream : nsISupports
{
/**
*
* Initialize the stream, setting up the amount of space that will be
* allocated for the stream's backing-store.
*
* @param segmentSize
* Size of each segment. Must be a power of two.
* @param maxSize
* Maximum total size of this stream. length will always be less
* than or equal to this value. Passing PR_UINT32_MAX is safe.
* @param segmentAllocator
* Which allocator to use for the segments. May be null, in which
* case a default allocator will be used.
*/
void init(in PRUint32 segmentSize, in PRUint32 maxSize, in nsIMemory segmentAllocator);
/**
* 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);
%}