/* ***** 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 necko content sniffer interface.
 *
 * The Initial Developer of the Original Code is
 * Christian Biesinger <cbiesinger@web.de>.
 * Portions created by the Initial Developer are Copyright (C) 2004
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either 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"

interface nsIRequest;

/**
 * Content sniffer interface. Components implementing this interface can
 * determine a MIME type from a chunk of bytes.
 */
[scriptable, uuid(a5772d1b-fc63-495e-a169-96e8d3311af0)]
interface nsIContentSniffer : nsISupports
{
  /**
   * Given a chunk of data, determines a MIME type. Information from the given
   * request may be used in order to make a better decision.
   *
   * @param aRequest The request where this data came from. May be null.
   * @param aData Data to check
   * @param aLength Length of the data
   *
   * @return The content type
   *
   * @throw NS_ERROR_NOT_AVAILABLE if no MIME type could be determined.
   *
   * @note Implementations should consider the request read-only. Especially,
   * they should not attempt to set the content type property that subclasses of
   * nsIRequest might offer.
   */
  ACString getMIMETypeFromContent(in nsIRequest aRequest,
                                  [const,array,size_is(aLength)] in octet aData,
                                  in unsigned long aLength);
};