gecko-dev/xpcom/io/nsICloneableInputStream.idl

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsIInputStream.idl"

[scriptable, builtinclass, uuid(8149be1f-44d3-4f14-8b65-a57a5fbbeb97)]
interface nsICloneableInputStream : nsISupports
{
  // Allow streams that implement the interface to determine if cloning
  // possible at runtime.  For example, this allows wrappers to check if
  // their base stream supports cloning.
  [infallible] readonly attribute boolean cloneable;

  // Produce a copy of the current stream in the most efficient way possible.
  // In this case "copy" means that both the original and cloned streams
  // should produce the same bytes for all future reads.  Bytes that have
  // already been consumed from the original stream are not copied to the
  // clone.  Operations on the two streams should be completely independent
  // after the clone() occurs.
  nsIInputStream clone();
};

// This interface implements cloneWithRange() because for some streams
// (RemoteLazyInputStream only, so far) are more efficient to produce a sub
// stream with range than doing clone + SlicedInputStream().
[scriptable, builtinclass, uuid(ece853c3-aded-4cef-8f51-0d1493d60bd5)]
interface nsICloneableInputStreamWithRange : nsICloneableInputStream
{
  nsIInputStream cloneWithRange(in uint64_t start, in uint64_t length);
};