glupload: add a helper function to convert drm formats into gst formats

Co-authored-by: Víctor Manuel Jáquez Leal <vjaquez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3524>

subprojects/gst-plugins-base/gst-libs/gst/gl/gstglupload.c

@@ -737,6 +737,124 @@ _dma_buf_transform_gst_formats_to_drm_formats (GstGLContext * context,
   return TRUE;
 }
 
+static gboolean
+_check_modifier (GstGLContext * context, guint32 fourcc,
+    guint64 modifier, gboolean include_external)
+{
+  const GArray *dma_modifiers;
+  guint i;
+
+  /* If no context provide, no further check. */
+  if (!context)
+    return TRUE;
+
+  if (!gst_gl_context_egl_get_format_modifiers (context, fourcc,
+          &dma_modifiers))
+    return FALSE;
+
+  if (!dma_modifiers) {
+    /* recognize the fourcc but no modifier info, consider it as linear */
+    if (modifier == DRM_FORMAT_MOD_LINEAR)
+      return TRUE;
+
+    return FALSE;
+  }
+
+  for (i = 0; i < dma_modifiers->len; i++) {
+    GstGLDmaModifier *mod = &g_array_index (dma_modifiers, GstGLDmaModifier, i);
+
+    if (!mod->external_only || include_external) {
+      if (mod->modifier == modifier)
+        return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
+static GstVideoFormat
+_get_video_format_from_drm_format (GstGLContext * context,
+    const gchar * drm_format, gboolean include_external)
+{
+  GstVideoFormat gst_format;
+  guint32 fourcc;
+  guint64 modifier;
+
+  fourcc = gst_video_dma_drm_fourcc_from_string (drm_format, &modifier);
+  if (fourcc == DRM_FORMAT_INVALID)
+    return GST_VIDEO_FORMAT_UNKNOWN;
+
+  gst_format = gst_video_dma_drm_fourcc_to_format (fourcc);
+  if (gst_format == GST_VIDEO_FORMAT_UNKNOWN)
+    return GST_VIDEO_FORMAT_UNKNOWN;
+
+  if (!_check_modifier (context, fourcc, modifier, include_external))
+    return GST_VIDEO_FORMAT_UNKNOWN;
+
+  return gst_format;
+}
+
+/* Given the drm formats in src GValue, collecting all the according
+   gst formats to dst GValue. Return FALSE if no valid drm formats found. */
+static gboolean
+_dma_buf_transform_drm_formats_to_gst_formats (GstGLContext * context,
+    const GValue * drm_value, gboolean include_external, GValue * video_value)
+{
+  GstVideoFormat gst_format;
+  GArray *all_formats = NULL;
+  guint i;
+
+  all_formats = g_array_new (FALSE, FALSE, sizeof (GstVideoFormat));
+
+  if (G_VALUE_HOLDS_STRING (drm_value)) {
+    gst_format = _get_video_format_from_drm_format (context,
+        g_value_get_string (drm_value), include_external);
+
+    if (gst_format != GST_VIDEO_FORMAT_UNKNOWN)
+      g_array_append_val (all_formats, gst_format);
+  } else if (GST_VALUE_HOLDS_LIST (drm_value)) {
+    guint num_values = gst_value_list_get_size (drm_value);
+
+    for (i = 0; i < num_values; i++) {
+      const GValue *val = gst_value_list_get_value (drm_value, i);
+
+      gst_format = _get_video_format_from_drm_format (context,
+          g_value_get_string (val), include_external);
+      if (gst_format == GST_VIDEO_FORMAT_UNKNOWN)
+        continue;
+
+      g_array_append_val (all_formats, gst_format);
+    }
+  }
+
+  if (all_formats->len == 0) {
+    g_array_unref (all_formats);
+    return FALSE;
+  }
+
+  if (all_formats->len == 1) {
+    g_value_init (video_value, G_TYPE_STRING);
+    gst_format = g_array_index (all_formats, GstVideoFormat, 0);
+    g_value_set_string (video_value, gst_video_format_to_string (gst_format));
+  } else {
+    GValue item = G_VALUE_INIT;
+
+    gst_value_list_init (video_value, all_formats->len);
+
+    for (i = 0; i < all_formats->len; i++) {
+      g_value_init (&item, G_TYPE_STRING);
+      gst_format = g_array_index (all_formats, GstVideoFormat, i);
+      g_value_set_string (&item, gst_video_format_to_string (gst_format));
+      gst_value_list_append_value (video_value, &item);
+      g_value_unset (&item);
+    }
+  }
+
+  g_array_unref (all_formats);
+
+  return TRUE;
+}
+
 static GstCaps *
 _dma_buf_upload_transform_caps (gpointer impl, GstGLContext * context,
     GstPadDirection direction, GstCaps * caps)