adaptivedemux2: Make download mechanism overrideable

Make the mechanism by which DownloadRequests are fulfilled overrideable by the
subclass, in case it has an internal mechanism it can use (such as blocking
preloads in HLS)

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3883>

subprojects/gst-plugins-good/ext/adaptivedemux2/gstadaptivedemux-stream.c

@@ -50,6 +50,9 @@ gst_adaptive_demux2_stream_update_current_bitrate (GstAdaptiveDemux2Stream *
     stream);
 static void gst_adaptive_demux2_stream_update_track_ids (GstAdaptiveDemux2Stream
     * stream);
+static GstFlowReturn
+gst_adaptive_demux2_stream_submit_request_default (GstAdaptiveDemux2Stream *
+    stream, DownloadRequest * download_req);
 
 #define gst_adaptive_demux2_stream_parent_class parent_class
 G_DEFINE_ABSTRACT_TYPE (GstAdaptiveDemux2Stream, gst_adaptive_demux2_stream,
@@ -64,6 +67,7 @@ gst_adaptive_demux2_stream_class_init (GstAdaptiveDemux2StreamClass * klass)
 
   klass->data_received = gst_adaptive_demux2_stream_data_received_default;
   klass->finish_fragment = gst_adaptive_demux2_stream_finish_fragment_default;
+  klass->submit_request = gst_adaptive_demux2_stream_submit_request_default;
 }
 
 static GType tsdemux_type = 0;
@@ -193,9 +197,8 @@ static void
 gst_adaptive_demux2_stream_handle_playlist_eos (GstAdaptiveDemux2Stream *
     stream);
 static GstFlowReturn
-gst_adaptive_demux2_stream_begin_download_uri (GstAdaptiveDemux * demux,
-    GstAdaptiveDemux2Stream * stream, const gchar * uri, gint64 start,
-    gint64 end);
+gst_adaptive_demux2_stream_begin_download_uri (GstAdaptiveDemux2Stream * stream,
+    const gchar * uri, gint64 start, gint64 end);
 
 #ifndef GST_DISABLE_GST_DEBUG
 static const char *
@@ -213,7 +216,6 @@ uritype (GstAdaptiveDemux2Stream * s)
 static gboolean
 schedule_another_chunk (GstAdaptiveDemux2Stream * stream)
 {
-  GstAdaptiveDemux *demux = stream->demux;
   DownloadRequest *request = stream->download_request;
   GstFlowReturn ret;
 
@@ -256,7 +258,7 @@ schedule_another_chunk (GstAdaptiveDemux2Stream * stream)
       " chunk_size %" G_GINT64_FORMAT, uri, range_start, chunk_end, chunk_size);
 
   ret =
-      gst_adaptive_demux2_stream_begin_download_uri (demux, stream, uri,
+      gst_adaptive_demux2_stream_begin_download_uri (stream, uri,
       range_start, chunk_end);
   if (ret != GST_FLOW_OK) {
     GST_DEBUG_OBJECT (stream,
@@ -1389,18 +1391,40 @@ on_download_complete (DownloadRequest * request, DownloadRequestState state,
   gst_adaptive_demux2_stream_finish_download (stream, ret, NULL);
 }
 
+static GstFlowReturn
+gst_adaptive_demux2_stream_submit_request_default (GstAdaptiveDemux2Stream *
+    stream, DownloadRequest * download_req)
+{
+  GstAdaptiveDemux *demux = stream->demux;
+
+  if (!downloadhelper_submit_request (demux->download_helper,
+          demux->manifest_uri, DOWNLOAD_FLAG_NONE, download_req, NULL))
+    return GST_FLOW_ERROR;
+
+  return GST_FLOW_OK;
+}
+
+static GstFlowReturn
+gst_adaptive_demux2_stream_submit_request (GstAdaptiveDemux2Stream * stream,
+    DownloadRequest * download_req)
+{
+  GstAdaptiveDemux2StreamClass *klass =
+      GST_ADAPTIVE_DEMUX2_STREAM_GET_CLASS (stream);
+  g_assert (klass->submit_request != NULL);
+  return klass->submit_request (stream, download_req);
+}
+
 /* must be called from the scheduler context
  *
  * Will submit the request only, which will complete asynchronously
  */
 static GstFlowReturn
-gst_adaptive_demux2_stream_begin_download_uri (GstAdaptiveDemux * demux,
-    GstAdaptiveDemux2Stream * stream, const gchar * uri, gint64 start,
-    gint64 end)
+gst_adaptive_demux2_stream_begin_download_uri (GstAdaptiveDemux2Stream * stream,
+    const gchar * uri, gint64 start, gint64 end)
 {
   DownloadRequest *request = stream->download_request;
 
-  GST_DEBUG_OBJECT (demux,
+  GST_DEBUG_OBJECT (stream,
       "Downloading %s uri: %s, range:%" G_GINT64_FORMAT " - %" G_GINT64_FORMAT,
       uritype (stream), uri, start, end);
 
@@ -1424,13 +1448,15 @@ gst_adaptive_demux2_stream_begin_download_uri (GstAdaptiveDemux * demux,
         (DownloadRequestEventCallback) on_download_progress, stream);
   }
 
-  if (!downloadhelper_submit_request (demux->download_helper,
-          demux->manifest_uri, DOWNLOAD_FLAG_NONE, request, NULL))
-    return GST_FLOW_ERROR;
 
   stream->download_active = TRUE;
+  GstFlowReturn ret =
+      gst_adaptive_demux2_stream_submit_request (stream, request);
+  if (ret != GST_FLOW_OK) {
+    stream->download_active = FALSE;
+  }
 
-  return GST_FLOW_OK;
+  return ret;
 }
 
 /* must be called from the scheduler context */
@@ -1469,7 +1495,7 @@ gst_adaptive_demux2_stream_download_fragment (GstAdaptiveDemux2Stream * stream)
 
     stream->downloading_header = TRUE;
 
-    return gst_adaptive_demux2_stream_begin_download_uri (demux, stream,
+    return gst_adaptive_demux2_stream_begin_download_uri (stream,
         stream->fragment.header_uri, stream->fragment.header_range_start,
         stream->fragment.header_range_end);
   }
@@ -1483,7 +1509,7 @@ gst_adaptive_demux2_stream_download_fragment (GstAdaptiveDemux2Stream * stream)
 
     stream->downloading_index = TRUE;
 
-    return gst_adaptive_demux2_stream_begin_download_uri (demux, stream,
+    return gst_adaptive_demux2_stream_begin_download_uri (stream,
         stream->fragment.index_uri, stream->fragment.index_range_start,
         stream->fragment.index_range_end);
   }
@@ -1516,14 +1542,14 @@ gst_adaptive_demux2_stream_download_fragment (GstAdaptiveDemux2Stream * stream)
     GST_DEBUG_OBJECT (stream,
         "Starting chunked download %s %" G_GINT64_FORMAT "-%" G_GINT64_FORMAT,
         url, range_start, chunk_end);
-    return gst_adaptive_demux2_stream_begin_download_uri (demux, stream, url,
+    return gst_adaptive_demux2_stream_begin_download_uri (stream, url,
         range_start, chunk_end);
   }
 
   /* regular single chunk download */
   stream->fragment.chunk_size = 0;
 
-  return gst_adaptive_demux2_stream_begin_download_uri (demux, stream, url,
+  return gst_adaptive_demux2_stream_begin_download_uri (stream, url,
       stream->fragment.range_start, stream->fragment.range_end);
 
 no_url_error:

subprojects/gst-plugins-good/ext/adaptivedemux2/gstadaptivedemux-stream.h

@@ -106,6 +106,19 @@ struct _GstAdaptiveDemux2StreamClass
    */
   GstFlowReturn (*update_fragment_info) (GstAdaptiveDemux2Stream * stream);
 
+  /**
+   * submit_request:
+   * @stream: #GstAdaptiveDemux2Stream
+   * @download_req: #DownloadRequest
+   *
+   * Requests the stream submit the provided download request for processing,
+   * either through the DownloadHelper (default), or through some sub-class
+   * mechanism
+   *
+   * Returns: #GST_FLOW_OK in success, #GST_FLOW_ERROR on error
+   */
+  GstFlowReturn (*submit_request) (GstAdaptiveDemux2Stream * stream, DownloadRequest * download_req);
+
   /**
    * finish_fragment:
    * @stream: #GstAdaptiveDemux2Stream