filesink: port over unlock code from fdsink

See also: 5216322d39

The previous code was causing "random" flushing returns
in scenarios with intensive state changes such as within
a buffering pipeline.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/476>

plugins/elements/gstfilesink.c

@@ -719,8 +719,8 @@ gst_file_sink_render_list_internal (GstFileSink * sink,
     GstBufferList * buffer_list)
 {
   GstFlowReturn flow;
-  guint64 bytes_written = 0;
   guint num_buffers;
+  guint64 skip = 0;
 
   num_buffers = gst_buffer_list_length (buffer_list);
   if (num_buffers == 0)
@@ -730,12 +730,25 @@ gst_file_sink_render_list_internal (GstFileSink * sink,
       "writing %u buffers at position %" G_GUINT64_FORMAT, num_buffers,
       sink->current_pos);
 
+  for (;;) {
+    guint64 bytes_written = 0;
+
     flow =
-      gst_writev_buffer_list (GST_OBJECT_CAST (sink), fileno (sink->file), NULL,
+        gst_writev_buffer_list (GST_OBJECT_CAST (sink), fileno (sink->file),
-      buffer_list, &bytes_written, 0, sink->max_transient_error_timeout,
+        NULL, buffer_list, &bytes_written, skip,
-      sink->current_pos, &sink->flushing);
+        sink->max_transient_error_timeout, sink->current_pos, &sink->flushing);
 
     sink->current_pos += bytes_written;
+    skip += bytes_written;
+
+    if (flow != GST_FLOW_FLUSHING)
+      break;
+
+    flow = gst_base_sink_wait_preroll (GST_BASE_SINK (sink));
+
+    if (flow != GST_FLOW_OK)
+      return flow;
+  }
 
   return flow;
 
@@ -755,16 +768,27 @@ gst_file_sink_flush_buffer (GstFileSink * filesink)
       filesink->current_buffer_size);
 
   if (filesink->buffer && filesink->current_buffer_size) {
+    guint64 skip = 0;
+
+    for (;;) {
       guint64 bytes_written = 0;
 
       flow_ret =
           gst_writev_mem (GST_OBJECT_CAST (filesink), fileno (filesink->file),
           NULL, filesink->buffer, filesink->current_buffer_size, &bytes_written,
-        0, filesink->max_transient_error_timeout, filesink->current_pos,
+          skip, filesink->max_transient_error_timeout, filesink->current_pos,
           &filesink->flushing);
 
       filesink->current_pos += bytes_written;
+      skip += bytes_written;
 
+      if (flow_ret != GST_FLOW_FLUSHING)
+        break;
+
+      flow_ret = gst_base_sink_wait_preroll (GST_BASE_SINK (filesink));
+      if (flow_ret != GST_FLOW_OK)
+        break;
+    }
   } else if (filesink->buffer_list && filesink->current_buffer_size) {
     guint length;
 
@@ -807,6 +831,35 @@ accumulate_size (GstBuffer ** buffer, guint idx, gpointer user_data)
   return TRUE;
 }
 
+static GstFlowReturn
+render_buffer (GstFileSink * filesink, GstBuffer * buffer)
+{
+  GstFlowReturn flow;
+  guint64 bytes_written = 0;
+  guint64 skip = 0;
+
+  for (;;) {
+    flow =
+        gst_writev_buffer (GST_OBJECT_CAST (filesink),
+        fileno (filesink->file), NULL, buffer, &bytes_written, skip,
+        filesink->max_transient_error_timeout, filesink->current_pos,
+        &filesink->flushing);
+
+    filesink->current_pos += bytes_written;
+    skip += bytes_written;
+
+    if (flow != GST_FLOW_FLUSHING)
+      break;
+
+    flow = gst_base_sink_wait_preroll (GST_BASE_SINK (filesink));
+
+    if (flow != GST_FLOW_OK)
+      break;
+  }
+
+  return flow;
+}
+
 static GstFlowReturn
 gst_file_sink_render_list (GstBaseSink * bsink, GstBufferList * buffer_list)
 {
@@ -851,20 +904,12 @@ gst_file_sink_render_list (GstBaseSink * bsink, GstBufferList * buffer_list)
         }
 
         if (buffer_size > sink->allocated_buffer_size) {
-          guint64 bytes_written = 0;
-
           GST_DEBUG_OBJECT (sink,
               "writing buffer ( %" G_GSIZE_FORMAT
               " bytes) at position %" G_GUINT64_FORMAT,
               buffer_size, sink->current_pos);
 
-          flow =
+          flow = render_buffer (sink, buffer);
-              gst_writev_buffer (GST_OBJECT_CAST (sink),
-              fileno (sink->file), NULL, buffer, &bytes_written, 0,
-              sink->max_transient_error_timeout, sink->current_pos,
-              &sink->flushing);
-
-          sink->current_pos += bytes_written;
         } else {
           sink->current_buffer_size +=
               gst_buffer_extract (buffer, 0,
@@ -925,20 +970,7 @@ gst_file_sink_render (GstBaseSink * sink, GstBuffer * buffer)
               && !filesink->buffer_list))) {
     flow = gst_file_sink_flush_buffer (filesink);
     if (flow == GST_FLOW_OK) {
-      guint64 bytes_written = 0;
+      flow = render_buffer (filesink, buffer);
-
-      GST_DEBUG_OBJECT (sink,
-          "writing buffer ( %" G_GSIZE_FORMAT
-          " bytes) at position %" G_GUINT64_FORMAT,
-          gst_buffer_get_size (buffer), filesink->current_pos);
-
-      flow =
-          gst_writev_buffer (GST_OBJECT_CAST (filesink),
-          fileno (filesink->file), NULL, buffer, &bytes_written, 0,
-          filesink->max_transient_error_timeout, filesink->current_pos,
-          &filesink->flushing);
-
-      filesink->current_pos += bytes_written;
     }
   } else if (n_mem > 0) {
     gsize size = gst_buffer_get_size (buffer);
@@ -957,20 +989,12 @@ gst_file_sink_render (GstBaseSink * sink, GstBuffer * buffer)
       }
 
       if (size > filesink->allocated_buffer_size) {
-        guint64 bytes_written = 0;
-
         GST_DEBUG_OBJECT (sink,
             "writing buffer ( %" G_GSIZE_FORMAT
             " bytes) at position %" G_GUINT64_FORMAT,
             size, filesink->current_pos);
 
-        flow =
+        flow = render_buffer (filesink, buffer);
-            gst_writev_buffer (GST_OBJECT_CAST (filesink),
-            fileno (filesink->file), NULL, buffer, &bytes_written, 0,
-            filesink->max_transient_error_timeout, filesink->current_pos,
-            &filesink->flushing);
-
-        filesink->current_pos += bytes_written;
       } else {
         filesink->current_buffer_size +=
             gst_buffer_extract (buffer, 0,
@@ -1024,7 +1048,6 @@ gst_file_sink_stop (GstBaseSink * basesink)
   filesink = GST_FILE_SINK_CAST (basesink);
 
   gst_file_sink_close_file (filesink);
-  g_atomic_int_set (&filesink->flushing, TRUE);
   return TRUE;
 }