From 4ee4a9bff96f2bc93796bfeadafe618fb6e5e94e Mon Sep 17 00:00:00 2001
From: Marek Vasut <marex@denx.de>
Date: Fri, 11 Feb 2022 23:44:20 +0100
Subject: [PATCH] jpegdec: Factor out gst_jpeg_turbo_parse_ext_fmt_convert()

Pull out peer caps checking code into gst_jpeg_turbo_parse_ext_fmt_convert().
This code is used by libjpeg-turbo extras to determine whether peer is capable
of handling buffers into which libjpeg-turbo can directly decode data. This
kind of check must be performed before jpeg_start_decompress() is called in
gst_jpeg_dec_prepare_decode() as well as in gst_jpeg_dec_negotiate(), hence
the common code.

This commit does modify the code a little to make it easier to call from both
call sites without much duplication, hence the extra `if (*clrspc)` test.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1687>
---
 .../gst-plugins-good/ext/jpeg/gstjpegdec.c    | 96 ++++++++++---------
 1 file changed, 53 insertions(+), 43 deletions(-)

diff --git a/subprojects/gst-plugins-good/ext/jpeg/gstjpegdec.c b/subprojects/gst-plugins-good/ext/jpeg/gstjpegdec.c
index db81b416a3..6e4199b06b 100644
--- a/subprojects/gst-plugins-good/ext/jpeg/gstjpegdec.c
+++ b/subprojects/gst-plugins-good/ext/jpeg/gstjpegdec.c
@@ -1008,6 +1008,55 @@ gst_fmt_to_jpeg_turbo_ext_fmt (GstVideoFormat gstfmt)
       return 0;
   }
 }
+
+static void
+gst_jpeg_turbo_parse_ext_fmt_convert (GstJpegDec * dec, gint * clrspc)
+{
+  GstCaps *peer_caps, *dec_caps;
+
+  dec_caps = gst_static_caps_get (&gst_jpeg_dec_src_pad_template.static_caps);
+  peer_caps =
+      gst_pad_peer_query_caps (GST_VIDEO_DECODER_SRC_PAD (dec), dec_caps);
+  gst_caps_unref (dec_caps);
+
+  GST_DEBUG ("Received caps from peer: %" GST_PTR_FORMAT, peer_caps);
+  dec->format_convert = FALSE;
+  if (!gst_caps_is_empty (peer_caps)) {
+    GstStructure *peerstruct;
+    const gchar *peerformat;
+    GstVideoFormat peerfmt;
+
+    if (!gst_caps_is_fixed (peer_caps))
+      peer_caps = gst_caps_fixate (peer_caps);
+
+    peerstruct = gst_caps_get_structure (peer_caps, 0);
+    peerformat = gst_structure_get_string (peerstruct, "format");
+    peerfmt = gst_video_format_from_string (peerformat);
+
+    switch (peerfmt) {
+      case GST_VIDEO_FORMAT_RGB:
+      case GST_VIDEO_FORMAT_RGBx:
+      case GST_VIDEO_FORMAT_xRGB:
+      case GST_VIDEO_FORMAT_RGBA:
+      case GST_VIDEO_FORMAT_ARGB:
+      case GST_VIDEO_FORMAT_BGR:
+      case GST_VIDEO_FORMAT_BGRx:
+      case GST_VIDEO_FORMAT_xBGR:
+      case GST_VIDEO_FORMAT_BGRA:
+      case GST_VIDEO_FORMAT_ABGR:
+        if (clrspc)
+          *clrspc = JCS_RGB;
+        dec->format = peerfmt;
+        dec->format_convert = TRUE;
+        dec->libjpeg_ext_format = gst_fmt_to_jpeg_turbo_ext_fmt (peerfmt);
+        break;
+      default:
+        break;
+    }
+  }
+  gst_caps_unref (peer_caps);
+  GST_DEBUG_OBJECT (dec, "format_convert=%d", dec->format_convert);
+}
 #endif
 
 static void
@@ -1017,7 +1066,6 @@ gst_jpeg_dec_negotiate (GstJpegDec * dec, gint width, gint height, gint clrspc,
   GstVideoCodecState *outstate;
   GstVideoInfo *info;
   GstVideoFormat format;
-  GstCaps *peer_caps, *dec_caps;
 
 #ifdef JCS_EXTENSIONS
   if (dec->format_convert) {
@@ -1052,48 +1100,10 @@ gst_jpeg_dec_negotiate (GstJpegDec * dec, gint width, gint height, gint clrspc,
     gst_video_codec_state_unref (outstate);
   }
 #ifdef JCS_EXTENSIONS
-  dec_caps = gst_static_caps_get (&gst_jpeg_dec_src_pad_template.static_caps);
-  peer_caps =
-      gst_pad_peer_query_caps (GST_VIDEO_DECODER_SRC_PAD (dec), dec_caps);
-  gst_caps_unref (dec_caps);
-
-  GST_DEBUG ("Received caps from peer: %" GST_PTR_FORMAT, peer_caps);
-  dec->format_convert = FALSE;
-  if (!gst_caps_is_empty (peer_caps)) {
-    GstStructure *peerstruct;
-    const gchar *peerformat;
-    GstVideoFormat peerfmt;
-
-    if (!gst_caps_is_fixed (peer_caps))
-      peer_caps = gst_caps_fixate (peer_caps);
-
-    peerstruct = gst_caps_get_structure (peer_caps, 0);
-    peerformat = gst_structure_get_string (peerstruct, "format");
-    peerfmt = gst_video_format_from_string (peerformat);
-
-    switch (peerfmt) {
-      case GST_VIDEO_FORMAT_RGB:
-      case GST_VIDEO_FORMAT_RGBx:
-      case GST_VIDEO_FORMAT_xRGB:
-      case GST_VIDEO_FORMAT_RGBA:
-      case GST_VIDEO_FORMAT_ARGB:
-      case GST_VIDEO_FORMAT_BGR:
-      case GST_VIDEO_FORMAT_BGRx:
-      case GST_VIDEO_FORMAT_xBGR:
-      case GST_VIDEO_FORMAT_BGRA:
-      case GST_VIDEO_FORMAT_ABGR:
-        clrspc = JCS_RGB;
-        format = peerfmt;
-        dec->format_convert = TRUE;
-        dec->libjpeg_ext_format = gst_fmt_to_jpeg_turbo_ext_fmt (peerfmt);
-        break;
-      default:
-        break;
-    }
-  }
-  dec->format = format;
-  gst_caps_unref (peer_caps);
-  GST_DEBUG_OBJECT (dec, "format_convert=%d", dec->format_convert);
+  /* Determine if libjpeg-turbo direct format conversion can be used
+   * with current caps and if so, adjust $dec to enable it and $clrspc
+   * accordingly. */
+  gst_jpeg_turbo_parse_ext_fmt_convert (dec, &clrspc);
 #endif
 
   outstate =