import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

netwerk/streamconv/nsIStreamConverter.idl

@@ -0,0 +1,100 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsIStreamListener.idl"
+
+interface nsIInputStream;
+
+/**
+ * nsIStreamConverter provides an interface to implement when you have code
+ * that converts data from one type to another.
+ *
+ * Suppose you had code that converted plain text into HTML. You could implement
+ * this interface to allow everyone else to use your conversion logic using a 
+ * standard api.
+ * <p>
+ * <b>STREAM CONVERTER USERS</b>
+ *
+ * There are currently two ways to use a stream converter:
+ * <ol>
+ * <li> <b>SYNCHRONOUS</b> Stream to Stream
+ *    You can supply the service with a stream of type X
+ *    and it will convert it to your desired output type and return
+ *    a converted (blocking) stream to you.</li>
+ *
+ * <li> <b>ASYNCHRONOUS</b> nsIStreamListener to nsIStreamListener
+ *    You can supply data directly to the converter by calling it's
+ *    nsIStreamListener::OnDataAvailable() method. It will then
+ *    convert that data from type X to your desired output type and
+ *    return converted data to you via the nsIStreamListener you passed
+ *    in by calling its OnDataAvailable() method.</li>
+ * </ol>
+ * <p>
+ *
+ * <b>STREAM CONVERTER SUPPLIERS</b>
+ *
+ * Registering a stream converter:
+ * Stream converter registration is a two step process. First of all the stream
+ * converter implementation must register itself with the component manager using
+ * a contractid in the format below. Second, the stream converter must add the contractid
+ * to the registry.
+ *
+ * Stream converter contractid format (the stream converter root key is defined in this
+ * file):
+ *
+ * <pre>@mozilla.org/streamconv;1?from=FROM_MIME_TYPE&to=TO_MIME_TYPE</pre>
+ *
+ * @author Jud Valeski
+ * @see nsIStreamConverterService
+ */
+
+[scriptable, uuid(0b6e2c69-5cf5-48b0-9dfd-c95950e2cc7b)]
+interface nsIStreamConverter : nsIStreamListener {
+
+    /**
+     * <b>SYNCRONOUS VERSION</b>
+     * Converts a stream of one type, to a stream of another type.
+     *
+     * Use this method when you have a stream you want to convert.
+     *
+     * @param aFromStream   The stream representing the original/raw data.
+     * @param aFromType     The MIME type of aFromStream.
+     * @param aToType       The MIME type of the returned stream.
+     * @param aCtxt         Either an opaque context, or a converter specific context
+     *                      (implementation specific).
+     * @return              The converted stream. NOTE: The returned stream may not
+     *                      already be converted. An efficient stream converter
+     *                      implementation will converter data on demand rather than
+     *                      buffering the converted data until it is used.
+     */
+    nsIInputStream convert(in nsIInputStream aFromStream,
+                           in string aFromType,
+                           in string aToType,
+                           in nsISupports aCtxt);
+
+    /**
+     * <b>ASYNCRONOUS VERSION</b>
+     * Converts data arriving via the converter's nsIStreamListener::OnDataAvailable() 
+     * method from one type to another, pushing the converted data out to the caller 
+     * via aListener::OnDataAvailable().
+     *
+     * Use this method when you want to proxy (and convert) nsIStreamListener callbacks
+     * asynchronously.
+     *
+     * @param aFromType     The MIME type of the original/raw data.
+     * @param aToType       The MIME type of the converted data.
+     * @param aListener     The listener who receives the converted data.
+     * @param aCtxt         Either an opaque context, or a converter specific context
+     *                      (implementation specific).
+     */
+    void asyncConvertData(in string aFromType,
+                          in string aToType,
+                          in nsIStreamListener aListener,
+                          in nsISupports aCtxt);
+};
+
+%{C++
+#define NS_ISTREAMCONVERTER_KEY         "@mozilla.org/streamconv;1"
+%}