win/idl/nsIUnicharStreamLoader.idl

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 * for the specific language governing rights and limitations under the
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 *
 * The Original Code is mozilla.org code.
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 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 2002
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 * Contributor(s):
 *    Darin Fisher <darin@netscape.com>  (original author)
 *
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#include "nsIStreamListener.idl"

interface nsIUnicharInputStream;
interface nsIUnicharStreamLoader;
interface nsIChannel;

[scriptable, uuid(6bb3e55b-69c0-4fc9-87e5-bed780d997ce)]
interface nsIUnicharStreamLoaderObserver : nsISupports
{
  /**
   * Called when the first full segment of data if available.
   *
   * @param aLoader the unichar stream loader
   * @param aContext the context parameter of the underlying channel
   * @param aFirstSegment the raw bytes of the first full data segment
   * @param aLength the length of aFirstSegment
   *
   * @return charset corresponding to this stream
   *
   * @note this method will only be called if the stream loader receives an
   *       OnDataAvailable call.
   */
  ACString onDetermineCharset(in nsIUnicharStreamLoader aLoader,
                              in nsISupports aContext,
                              [size_is(aLength)] in string aFirstSegment,
                              in unsigned long aLength);

  /**
   * Called when the entire stream has been loaded.
   *
   * @param aLoader the unichar stream loader
   * @param aContext the context parameter of the underlying channel
   * @param aStatus the status of the underlying channel
   * @param aUnicharData the unichar input stream containing the data.  This
   *        can be null in some failure conditions.
   *
   * This method will always be called asynchronously by the
   * nsUnicharIStreamLoader involved, on the thread that called the
   * loader's init() method.
   *
   * @note If the stream loader does not receive an OnDataAvailable call,
   *       aUnicharData will be null, and aStatus will be a success value.
   */
  void onStreamComplete(in nsIUnicharStreamLoader aLoader,
                        in nsISupports aContext,
                        in nsresult aStatus,
                        in nsIUnicharInputStream aUnicharData);
};

/**
 * Asynchronously load a channel, converting the data to UTF-16.
 *
 * To use this interface, first call init() with a
 * nsIUnicharStreamLoaderObserver that will be notified when the data has been
 * loaded. Then call asyncOpen() on the channel with the nsIUnicharStreamLoader
 * as the listener. The context argument in the asyncOpen() call will be
 * passed to the onStreamComplete() callback.
 */
[scriptable, uuid(9037f476-7c08-4729-b690-3e425269802b)]
interface nsIUnicharStreamLoader : nsIStreamListener
{
  const unsigned long DEFAULT_SEGMENT_SIZE = 4096;

  /**
   * Initializes the unichar stream loader
   *
   * @param aObserver the observer to notify when a charset is needed and when
   *        the load is complete
   * @param aSegmentSize the size of the segments to use for the data, in bytes
   */
  
  void init(in nsIUnicharStreamLoaderObserver aObserver,
            in unsigned long aSegmentSize);

  /**
   * The channel attribute is only valid inside the onDetermineCharset
   * and onStreamComplete callbacks.  Otherwise it will be null.
   */
  readonly attribute nsIChannel channel;

  /**
   * The charset that onDetermineCharset returned, if that's been
   * called.
   */
  readonly attribute ACString charset;
};