The Tor Browser: xpcom/io/nsIStorageStream.idl@97036ab72558

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "nsISupports.idl"

     8 interface nsIInputStream;

     9 interface nsIOutputStream;

    11 /**

    12  * The nsIStorageStream interface maintains an internal data buffer that can be

    13  * filled using a single output stream.  One or more independent input streams

    14  * can be created to read the data from the buffer non-destructively.

    15  */

    17 [scriptable, uuid(44a200fe-6c2b-4b41-b4e3-63e8c14e7c0d)]

    18 interface nsIStorageStream : nsISupports

    19 {

    20     /**

    21      *

    22      * Initialize the stream, setting up the amount of space that will be

    23      * allocated for the stream's backing-store.

    24      *

    25      * @param segmentSize

    26      *        Size of each segment. Must be a power of two.

    27      * @param maxSize

    28      *        Maximum total size of this stream. length will always be less

    29      *        than or equal to this value. Passing UINT32_MAX is safe.

    30      */

    31     void init(in uint32_t segmentSize, in uint32_t maxSize);

    33     /**

    34      * Get a reference to the one and only output stream for this instance.

    35      * The zero-based startPosition argument is used is used to set the initial

    36      * write cursor position.  The startPosition cannot be set larger than the

    37      * current buffer length.  Calling this method has the side-effect of

    38      * truncating the internal buffer to startPosition bytes.

    39      */

    40     nsIOutputStream getOutputStream(in int32_t startPosition);

    42     /**

    43      * Create a new input stream to read data (written by the singleton output

    44      * stream) from the internal buffer.  Multiple, independent input streams

    45      * can be created.

    46      */

    47     nsIInputStream newInputStream(in int32_t startPosition);

    49     /**

    50      * The length attribute indicates the total number of bytes stored in the

    51      * nsIStorageStream internal buffer, regardless of any consumption by input

    52      * streams.  Assigning to the length field can be used to truncate the

    53      * buffer data, but can not be used when either the instance's output

    54      * stream is in use.

    55      *

    56      * @See #writeInProgress */

    57     attribute uint32_t length;

    59     /**

    60      * True, when output stream has not yet been Close'ed

    61      */

    62     readonly attribute boolean writeInProgress;

    63 };

    65 %{C++

    66 // Factory method

    67 nsresult

    68 NS_NewStorageStream(uint32_t segmentSize, uint32_t maxSize, nsIStorageStream **result);

    69 %}

The Tor Browser / file revision

xpcom/io/nsIStorageStream.idl@97036ab72558

xpcom/io/nsIStorageStream.idl