pulsecore: Don't allow unreferencing linked object.

Sink(-input) and source(-output) called unlink function when reference
count dropped to zero. This would result in unlink hooks being called
with an object having a reference count of zero, and this is not a
situation we want modules to have to deal with. It is better to just
remove the redundant unlinking code from sink(-input) and
source(-output) and assert on reference count in unlink functions as well.

It is expected that in well behaving code the owner of an object will
always unlink the object before unreferencing.

Signed-off-by: Arun Raghavan <arun@arunraghavan.net>

4 files changed, 9 insertions, 16 deletions

diff --git a/src/pulsecore/sink-input.c b/src/pulsecore/sink-input.c
index c7d99efbf..a7f6d5512 100644
--- a/src/pulsecore/sink-input.c
+++ b/src/pulsecore/sink-input.c
@@ -645,7 +645,7 @@ void pa_sink_input_unlink(pa_sink_input *i) {
     bool linked;
     pa_source_output *o, PA_UNUSED *p = NULL;
 
-    pa_assert(i);
+    pa_sink_input_assert_ref(i);
     pa_assert_ctl_context();
 
     /* See pa_sink_unlink() for a couple of comments how this function
@@ -721,9 +721,7 @@ static void sink_input_free(pa_object *o) {
     pa_assert(i);
     pa_assert_ctl_context();
     pa_assert(pa_sink_input_refcnt(i) == 0);
-
-    if (PA_SINK_INPUT_IS_LINKED(i->state))
-        pa_sink_input_unlink(i);
+    pa_assert(!PA_SINK_INPUT_IS_LINKED(i->state));
 
     pa_log_info("Freeing input %u \"%s\"", i->index,
                 i->proplist ? pa_strnull(pa_proplist_gets(i->proplist, PA_PROP_MEDIA_NAME)) : "");
diff --git a/src/pulsecore/sink.c b/src/pulsecore/sink.c
index 3f1ef725b..9bdf9be08 100644
--- a/src/pulsecore/sink.c
+++ b/src/pulsecore/sink.c
@@ -669,7 +669,7 @@ void pa_sink_unlink(pa_sink* s) {
     bool linked;
     pa_sink_input *i, PA_UNUSED *j = NULL;
 
-    pa_assert(s);
+    pa_sink_assert_ref(s);
     pa_assert_ctl_context();
 
     /* Please note that pa_sink_unlink() does more than simply
@@ -722,9 +722,7 @@ static void sink_free(pa_object *o) {
     pa_assert(s);
     pa_assert_ctl_context();
     pa_assert(pa_sink_refcnt(s) == 0);
-
-    if (PA_SINK_IS_LINKED(s->state))
-        pa_sink_unlink(s);
+    pa_assert(!PA_SINK_IS_LINKED(s->state));
 
     pa_log_info("Freeing sink %u \"%s\"", s->index, s->name);
 
diff --git a/src/pulsecore/source-output.c b/src/pulsecore/source-output.c
index 6af1543ac..9e951ff61 100644
--- a/src/pulsecore/source-output.c
+++ b/src/pulsecore/source-output.c
@@ -548,7 +548,8 @@ static void source_output_set_state(pa_source_output *o, pa_source_output_state_
 /* Called from main context */
 void pa_source_output_unlink(pa_source_output*o) {
     bool linked;
-    pa_assert(o);
+
+    pa_source_output_assert_ref(o);
     pa_assert_ctl_context();
 
     /* See pa_sink_unlink() for a couple of comments how this function
@@ -614,9 +615,7 @@ static void source_output_free(pa_object* mo) {
     pa_assert(o);
     pa_assert_ctl_context();
     pa_assert(pa_source_output_refcnt(o) == 0);
-
-    if (PA_SOURCE_OUTPUT_IS_LINKED(o->state))
-        pa_source_output_unlink(o);
+    pa_assert(!PA_SOURCE_OUTPUT_IS_LINKED(o->state));
 
     pa_log_info("Freeing output %u \"%s\"", o->index,
                 o->proplist ? pa_strnull(pa_proplist_gets(o->proplist, PA_PROP_MEDIA_NAME)) : "");
diff --git a/src/pulsecore/source.c b/src/pulsecore/source.c
index 98374ae92..8a527d8a9 100644
--- a/src/pulsecore/source.c
+++ b/src/pulsecore/source.c
@@ -612,7 +612,7 @@ void pa_source_unlink(pa_source *s) {
     bool linked;
     pa_source_output *o, PA_UNUSED *j = NULL;
 
-    pa_assert(s);
+    pa_source_assert_ref(s);
     pa_assert_ctl_context();
 
     /* See pa_sink_unlink() for a couple of comments how this function
@@ -661,9 +661,7 @@ static void source_free(pa_object *o) {
     pa_assert(s);
     pa_assert_ctl_context();
     pa_assert(pa_source_refcnt(s) == 0);
-
-    if (PA_SOURCE_IS_LINKED(s->state))
-        pa_source_unlink(s);
+    pa_assert(!PA_SOURCE_IS_LINKED(s->state));
 
     pa_log_info("Freeing source %u \"%s\"", s->index, s->name);