From 283c21564186ee7d5dfc3dec28f355c8112b1d45 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Mon, 11 Dec 2023 13:01:10 +0100
Subject: [PATCH] stream: make empty objects remove the PARAM

Make sure that NULL params don't cause -EINVAL but ignore them.

Don't add empty param objects. this makes it possible to clear all previous
params by setting an empty object.
---
 spa/include/spa/pod/iter.h |  8 ++++++++
 src/pipewire/filter.c      | 22 ++++++++++------------
 src/pipewire/stream.c      | 19 +++++++++----------
 3 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/spa/include/spa/pod/iter.h b/spa/include/spa/pod/iter.h
index 05abfc1c9..8e97130f8 100644
--- a/spa/include/spa/pod/iter.h
+++ b/spa/include/spa/pod/iter.h
@@ -437,6 +437,14 @@ static inline int spa_pod_object_is_fixated(const struct spa_pod_object *pod)
 	return 1;
 }
 
+static inline int spa_pod_object_has_props(const struct spa_pod_object *pod)
+{
+	struct spa_pod_prop *res;
+	SPA_POD_OBJECT_FOREACH(pod, res)
+		return 1;
+	return 0;
+}
+
 static inline int spa_pod_is_fixated(const struct spa_pod *pod)
 {
 	if (!spa_pod_is_object(pod))
diff --git a/src/pipewire/filter.c b/src/pipewire/filter.c
index 6dbf050ea..7412aedd4 100644
--- a/src/pipewire/filter.c
+++ b/src/pipewire/filter.c
@@ -224,22 +224,23 @@ static void fix_datatype(struct spa_pod *param)
 	}
 }
 
-static struct param *add_param(struct filter *impl, struct port *port,
+static int add_param(struct filter *impl, struct port *port,
 		uint32_t id, uint32_t flags, const struct spa_pod *param)
 {
 	struct param *p;
 	int idx;
 
-	if (param == NULL || !spa_pod_is_object(param)) {
-		errno = EINVAL;
-		return NULL;
-	}
+	if (param != NULL && !spa_pod_is_object(param))
+		return -EINVAL;
+	if (param == NULL || !spa_pod_object_has_props((struct spa_pod_object*)param))
+		return 0;
+
 	if (id == SPA_ID_INVALID)
 		id = SPA_POD_OBJECT_ID(param);
 
 	p = malloc(sizeof(struct param) + SPA_POD_SIZE(param));
 	if (p == NULL)
-		return NULL;
+		return -errno;
 
 	if (id == SPA_PARAM_ProcessLatency && port == NULL)
 		spa_process_latency_parse(param, &impl->process_latency);
@@ -275,7 +276,7 @@ static struct param *add_param(struct filter *impl, struct port *port,
 			impl->params[idx].user++;
 		}
 	}
-	return p;
+	return 0;
 }
 
 static void clear_params(struct filter *impl, struct port *port, uint32_t id)
@@ -702,10 +703,8 @@ static int update_params(struct filter *impl, struct port *port, uint32_t id,
 			}
 			continue;
 		}
-		if (add_param(impl, port, id, 0, params[i]) == NULL) {
-			res = -errno;
+		if ((res = add_param(impl, port, id, 0, params[i])) < 0)
 			break;
-		}
 	}
 	if (port != NULL && update_latency) {
 		uint8_t buffer[4096];
@@ -1636,9 +1635,8 @@ pw_filter_connect(struct pw_filter *filter,
 	impl->info.change_mask = impl->change_mask_all;
 
 	clear_params(impl, NULL, SPA_ID_INVALID);
-	for (i = 0; i < n_params; i++) {
+	for (i = 0; i < n_params; i++)
 		add_param(impl, NULL, SPA_ID_INVALID, 0, params[i]);
-	}
 
 	impl->disconnecting = false;
 	impl->draining = false;
diff --git a/src/pipewire/stream.c b/src/pipewire/stream.c
index d9fae3330..ee35c4f0a 100644
--- a/src/pipewire/stream.c
+++ b/src/pipewire/stream.c
@@ -226,22 +226,23 @@ static void fix_datatype(struct spa_pod *param)
 	}
 }
 
-static struct param *add_param(struct stream *impl,
+static int add_param(struct stream *impl,
 		uint32_t id, uint32_t flags, const struct spa_pod *param)
 {
 	struct param *p;
 	int idx;
 
-	if (param == NULL || !spa_pod_is_object(param)) {
-		errno = EINVAL;
-		return NULL;
-	}
+	if (param != NULL && !spa_pod_is_object(param))
+		return -EINVAL;
+	if (param == NULL || !spa_pod_object_has_props((struct spa_pod_object*)param))
+		return 0;
+
 	if (id == SPA_ID_INVALID)
 		id = SPA_POD_OBJECT_ID(param);
 
 	p = malloc(sizeof(struct param) + SPA_POD_SIZE(param));
 	if (p == NULL)
-		return NULL;
+		return -errno;
 
 	p->id = id;
 	p->flags = flags;
@@ -266,7 +267,7 @@ static struct param *add_param(struct stream *impl,
 		impl->port_params[idx].flags |= SPA_PARAM_INFO_READ;
 		impl->port_params[idx].user++;
 	}
-	return p;
+	return 0;
 }
 
 static void clear_params(struct stream *impl, uint32_t id)
@@ -326,10 +327,8 @@ static int update_params(struct stream *impl, uint32_t id,
 		}
 	}
 	for (i = 0; i < n_params; i++) {
-		if (add_param(impl, id, 0, params[i]) == NULL) {
-			res = -errno;
+		if ((res = add_param(impl, id, 0, params[i])) < 0)
 			break;
-		}
 	}
 	return res;
 }