netwerk/streamconv/public/nsIStreamConverterService.idl

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  37
  38 #include "nsIInputStream.idl"
  39 #include "nsIStreamListener.idl"
  40
  41 %{C++
  42 #define NS_ISTREAMCONVERTER_KEY         "@mozilla.org/streamconv;1"
  43 %}
  44
  45 /**
  46  * The nsIStreamConverterService is a higher level stream converter factory
  47  * responsible for locating and creating stream converters
  48  * (nsIStreamConverter).
  49  *
  50  * This service retrieves an interface that can convert data from a particular
  51  * MIME type, to a particular MIME type. It is responsible for any intermediary
  52  * conversion required in order to get from X to Z, assuming direct conversion
  53  * is not possible.
  54  *
  55  * @author Jud Valeski
  56  * @see nsIStreamConverter
  57  */
  58 [scriptable, uuid(f2b1ab53-f0bd-4adb-9365-e59b1701a258)]
  59 interface nsIStreamConverterService : nsISupports {
  60     /**
  61      * Tests whether conversion between the two specified types is possible.
  62      * This is cheaper than calling convert()/asyncConvertData(); it is not
  63      * necessary to call this function before calling one of those, though.
  64      */
  65     boolean canConvert(in string aFromType, in string aToType);
  66
  67     /**
  68      * <b>SYNCHRONOUS VERSION</b>
  69      * Converts a stream of one type, to a stream of another type.
  70      *
  71      * Use this method when you have a stream you want to convert.
  72      *
  73      * @param aFromStream   The stream representing the original/raw data.
  74      * @param aFromType     The MIME type of aFromStream.
  75      * @param aToType       The MIME type of the returned stream.
  76      * @param aContext      Either an opaque context, or a converter specific
  77      *                      context (implementation specific).
  78      * @return              The converted stream. NOTE: The returned stream
  79      *                      may not already be converted. An efficient stream
  80      *                      converter implementation will convert data on
  81      *                      demand rather than buffering the converted data
  82      *                      until it is used.
  83      */
  84     nsIInputStream convert(in nsIInputStream aFromStream,
  85                            in string aFromType,
  86                            in string aToType,
  87                            in nsISupports aContext);
  88
  89     /**
  90      * <b>ASYNCHRONOUS VERSION</b>
  91      * Retrieves a nsIStreamListener that receives the original/raw data via its
  92      * nsIStreamListener::OnDataAvailable() callback, then converts and pushes
  93      * the data to aListener.
  94      *
  95      * Use this method when you want to proxy (and convert) nsIStreamListener
  96      * callbacks asynchronously.
  97      *
  98      * @param aFromType     The MIME type of the original/raw data.
  99      * @param aToType       The MIME type of the converted data.
 100      * @param aListener     The listener that receives the converted data.
 101      * @param aCtxt         Either an opaque context, or a converter specific
 102      *                      context (implementation specific).
 103      * @return              A nsIStreamListener that receives data via its
 104      *                      OnDataAvailable() method.
 105      */
 106     nsIStreamListener asyncConvertData(in string aFromType,
 107                                        in string aToType,
 108                                        in nsIStreamListener aListener,
 109                                        in nsISupports aContext);
 110 };