link: improve renegotiation

Only suspend an idle node when we need to configure a different format.

spa/lib/format.c

@@ -59,3 +59,20 @@ spa_format_filter(const struct spa_format *format,
 
 	return res;
 }
+
+int
+spa_format_compare(const struct spa_format *format1,
+		   const struct spa_format *format2)
+{
+	if (format1 == NULL || format2 == NULL)
+		return SPA_RESULT_INVALID_ARGUMENTS;
+
+	if (SPA_FORMAT_MEDIA_TYPE(format1) != SPA_FORMAT_MEDIA_TYPE(format2) ||
+	    SPA_FORMAT_MEDIA_SUBTYPE(format1) != SPA_FORMAT_MEDIA_SUBTYPE(format2))
+		return SPA_RESULT_INVALID_MEDIA_TYPE;
+
+	return spa_props_compare(SPA_POD_CONTENTS(struct spa_format, format1),
+				 SPA_POD_CONTENTS_SIZE(struct spa_format, format1),
+				 SPA_POD_CONTENTS(struct spa_format, format2),
+				 SPA_POD_CONTENTS_SIZE(struct spa_format, format2));
+}

spa/lib/format.h

@@ -0,0 +1,40 @@
+/* Simple Plugin API
+ * Copyright (C) 2016 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __SPA_LIBFORMAT_H__
+#define __SPA_LIBFORMAT_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <spa/props.h>
+
+int spa_format_filter(const struct spa_format *format,
+		      const struct spa_format *filter,
+		      struct spa_pod_builder *result);
+
+int spa_format_compare(const struct spa_format *format1,
+		       const struct spa_format *format2);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* __SPA_LIBFORMAT_H__ */

spa/lib/meson.build

@@ -1,5 +1,6 @@
 spalib_headers = [
   'debug.h',
+  'format.h',
   'props.h',
 ]
 

spa/lib/props.c

@@ -310,3 +310,40 @@ spa_props_filter(struct spa_pod_builder *b,
 	}
 	return SPA_RESULT_OK;
 }
+
+int spa_props_compare(const struct spa_pod *props1,
+                      uint32_t props1_size,
+                      const struct spa_pod *props2,
+                      uint32_t props2_size)
+{
+	const struct spa_pod *pr;
+
+	SPA_POD_FOREACH(props1, props1_size, pr) {
+		struct spa_pod_prop *p1, *p2;
+		void *a1, *a2;
+
+		if (pr->type != SPA_POD_TYPE_PROP)
+			continue;
+
+		p1 = (struct spa_pod_prop *) pr;
+
+		if ((p2 = find_prop(props2, props2_size, p1->body.key)) == NULL)
+			return SPA_RESULT_INCOMPATIBLE_PROPS;
+
+		/* incompatible property types */
+		if (p1->body.value.type != p2->body.value.type)
+			return SPA_RESULT_INCOMPATIBLE_PROPS;
+
+		if (p1->body.flags & SPA_POD_PROP_FLAG_UNSET ||
+		    p2->body.flags & SPA_POD_PROP_FLAG_UNSET)
+			return SPA_RESULT_INCOMPATIBLE_PROPS;
+
+		a1 = SPA_MEMBER(p1, sizeof(struct spa_pod_prop), void);
+		a2 = SPA_MEMBER(p2, sizeof(struct spa_pod_prop), void);
+
+		if (compare_value(p1->body.value.type, a1, a2) != 0)
+			return SPA_RESULT_INCOMPATIBLE_PROPS;
+	}
+	return SPA_RESULT_OK;
+
+}

spa/lib/props.h

@@ -32,6 +32,10 @@ int spa_props_filter(struct spa_pod_builder *b,
 		     const struct spa_pod *filter,
 		     uint32_t filter_size);
 
+int spa_props_compare(const struct spa_pod *props1,
+		      uint32_t props1_size,
+		      const struct spa_pod *props2,
+		      uint32_t props2_size);
 #ifdef __cplusplus
 } /* extern "C" */
 #endif