xpcom/io/nsISeekableStream.idl

   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/. */
   5
   6
   7 #include "nsITellableStream.idl"
   8
   9 /*
  10  * nsISeekableStream
  11  *
  12  * Note that a stream might not implement all methods (e.g., a readonly stream
  13  * won't implement setEOF)
  14  */
  15
  16 #include "nsISupports.idl"
  17
  18 [scriptable, uuid(8429d350-1040-4661-8b71-f2a6ba455980)]
  19 interface nsISeekableStream : nsITellableStream
  20 {
  21     /*
  22      * Sets the stream pointer to the value of the 'offset' parameter
  23      */
  24     const int32_t NS_SEEK_SET = 0;
  25
  26     /*
  27      * Sets the stream pointer to its current location plus the value
  28      * of the offset parameter.
  29      */
  30     const int32_t NS_SEEK_CUR = 1;
  31
  32     /*
  33      * Sets the stream pointer to the size of the stream plus the value
  34      * of the offset parameter.
  35      */
  36     const int32_t NS_SEEK_END = 2;
  37
  38     /**
  39      *  seek
  40      *
  41      *  This method moves the stream offset of the steam implementing this
  42      *  interface.
  43      *
  44      *   @param whence specifies how to interpret the 'offset' parameter in
  45      *                 setting the stream offset associated with the implementing
  46      *                 stream.
  47      *
  48      *   @param offset specifies a value, in bytes, that is used in conjunction
  49      *                 with the 'whence' parameter to set the stream offset of the
  50      *                 implementing stream.  A negative value causes seeking in
  51      *                 the reverse direction.
  52      *
  53      *   @throws NS_BASE_STREAM_CLOSED if called on a closed stream.
  54      */
  55     void seek(in long whence, in long long offset);
  56
  57     /**
  58      *  setEOF
  59      *
  60      *  This method truncates the stream at the current offset.
  61      *
  62      *   @throws NS_BASE_STREAM_CLOSED if called on a closed stream.
  63      */
  64     void setEOF();
  65 };