allow dds_create_topic multiple times for the same topic

Signed-off-by: Erik Boasson <eb@ilities.com>

src/core/ddsc/include/ddsc/dds_public_qos.h

@@ -195,6 +195,21 @@ void dds_qos_merge
     _In_ const dds_qos_t * __restrict src
 );
 
+/**
+ * @brief Copy all QoS-policies from one structure to another, unless already set
+ *
+ * Policies are copied from src to dst, unless src already has the policy set to a non-default value.
+ *
+ * @param[in,out] dst - Pointer to the destination qos structure
+ * @param[in] src - Pointer to the source qos structure
+ */
+DDS_EXPORT
+bool dds_qos_equal
+(
+    _In_ const dds_qos_t * __restrict a,
+    _In_ const dds_qos_t * __restrict b
+);
+
 /**
  * @brief Set the userdata of a qos structure.
  *

src/core/ddsc/src/dds_qos.c

@@ -244,16 +244,30 @@ void dds_qos_merge (
 {
     if(!src){
         DDS_ERROR(DDS_RETCODE_BAD_PARAMETER, "Argument source(src) is NULL");
-        return ;
+        return;
     }
     if(!dst){
         DDS_ERROR(DDS_RETCODE_BAD_PARAMETER, "Argument destination(dst) is NULL");
-        return ;
+        return;
     }
     /* Copy qos from source to destination unless already set */
     nn_xqos_mergein_missing (dst, src);
 }
 
+bool dds_qos_equal (
+    _In_opt_ const dds_qos_t * __restrict a,
+    _In_opt_ const dds_qos_t * __restrict b)
+{
+    /* FIXME: a bit of a hack - and I am not so sure I like accepting null pointers here anyway */
+    if (a == NULL && b == NULL) {
+        return true;
+    } else if (a == NULL || b == NULL) {
+        return false;
+    } else {
+        return nn_xqos_delta(a, b, ~(uint64_t)0) != 0;
+    }
+}
+
 void dds_qset_userdata(
     _Inout_ dds_qos_t * __restrict qos,
     _In_reads_bytes_opt_(sz) const void * __restrict value,

src/core/ddsc/src/dds_topic.c

@@ -153,7 +153,7 @@ dds_topic_status_cb(
 }
 
 sertopic_t
-dds_topic_lookup(
+dds_topic_lookup_locked(
         dds_domain *domain,
         const char *name)
 {
@@ -163,7 +163,6 @@ dds_topic_lookup(
     assert (domain);
     assert (name);
 
-    os_mutexLock (&dds_global.m_mutex);
     st = ut_avlIterFirst (&dds_topictree_def, &domain->m_topics, &iter);
     while (st) {
         if (strcmp (st->name, name) == 0) {
@@ -171,6 +170,17 @@ dds_topic_lookup(
         }
         st = ut_avlIterNext (&iter);
     }
+    return st;
+}
+
+sertopic_t
+dds_topic_lookup(
+        dds_domain *domain,
+        const char *name)
+{
+    sertopic_t st;
+    os_mutexLock (&dds_global.m_mutex);
+    st = dds_topic_lookup_locked(domain, name);
     os_mutexUnlock (&dds_global.m_mutex);
     return st;
 }
@@ -195,16 +205,14 @@ dds_topic_free(
 }
 
 static void
-dds_topic_add(
+dds_topic_add_locked(
         dds_domainid_t id,
         sertopic_t st)
 {
     dds_domain * dom;
-    os_mutexLock (&dds_global.m_mutex);
     dom = dds_domain_find_locked (id);
     assert (dom);
     ut_avlInsert (&dds_topictree_def, &dom->m_topics, st);
-    os_mutexUnlock (&dds_global.m_mutex);
 }
 
 _Pre_satisfies_((participant & DDS_ENTITY_KIND_MASK) == DDS_KIND_PARTICIPANT)
@@ -223,13 +231,15 @@ dds_find_topic(
     if (name) {
         rc = dds_entity_lock(participant, DDS_KIND_PARTICIPANT, &p);
         if (rc == DDS_RETCODE_OK) {
-            st = dds_topic_lookup (p->m_domain, name);
+            os_mutexLock (&dds_global.m_mutex);
+            st = dds_topic_lookup_locked (p->m_domain, name);
             if (st) {
                 dds_entity_add_ref (&st->status_cb_entity->m_entity);
                 tp = st->status_cb_entity->m_entity.m_hdl;
             } else {
                 tp = DDS_ERRNO(DDS_RETCODE_PRECONDITION_NOT_MET, "Topic is not being created yet");
             }
+            os_mutexUnlock (&dds_global.m_mutex);
             dds_entity_unlock(p);
         } else {
             tp = DDS_ERRNO(rc, "Error occurred on locking entity");
@@ -297,6 +307,17 @@ dds_topic_qos_set(
     return ret;
 }
 
+static bool dupdef_qos_ok(const dds_qos_t *qos, const struct sertopic *st)
+{
+    if ((qos == NULL) != (st->status_cb_entity->m_entity.m_qos == NULL)) {
+        return false;
+    } else if (qos == NULL) {
+        return true;
+    } else {
+        return dds_qos_equal(st->status_cb_entity->m_entity.m_qos, qos);
+    }
+}
+
 _Pre_satisfies_((participant & DDS_ENTITY_KIND_MASK) == DDS_KIND_PARTICIPANT)
 DDS_EXPORT dds_entity_t
 dds_create_topic(
@@ -353,12 +374,23 @@ dds_create_topic(
         }
     }
 
-    /* Check if topic already exists with same name */
-    if (dds_topic_lookup (par->m_domain, name)) {
-        hdl = DDS_ERRNO(DDS_RETCODE_PRECONDITION_NOT_MET, "Precondition not met");
-        goto qos_err;
-    }
+    /* FIXME: I find it weird that qos may be NULL in the entity */
 
+    /* Check if topic already exists with same name */
+    os_mutexLock (&dds_global.m_mutex);
+    if ((st = dds_topic_lookup_locked (par->m_domain, name)) != NULL) {
+        if (st->type != desc) {
+            /* FIXME: should copy the type, perhaps? but then the pointers will no longer be the same */
+            hdl = DDS_ERRNO(DDS_RETCODE_PRECONDITION_NOT_MET, "Create topic with mismatching type.");
+        } else if (!dupdef_qos_ok(qos, st)) {
+            /* FIXME: should copy the type, perhaps? but then the pointers will no longer be the same */
+            hdl = DDS_ERRNO(DDS_RETCODE_INCONSISTENT_POLICY, "Create topic with mismatching qos.");
+        } else {
+            dds_entity_add_ref (&st->status_cb_entity->m_entity);
+            hdl = st->status_cb_entity->m_entity.m_hdl;
+        }
+        os_mutexUnlock (&dds_global.m_mutex);
+    } else {
         typename = desc->m_typename;
         key = (char*) dds_alloc (strlen (name) + strlen (typename) + 2);
         strcpy (key, name);
@@ -408,7 +440,8 @@ dds_create_topic(
         top->m_stopic = st;
 
         /* Add topic to extent */
-    dds_topic_add (par->m_domainid, st);
+        dds_topic_add_locked (par->m_domainid, st);
+        os_mutexUnlock (&dds_global.m_mutex);
 
         nn_plist_init_empty (&plist);
         if (new_qos) {
@@ -444,6 +477,7 @@ dds_create_topic(
             thread_state_asleep (thr);
         }
         nn_plist_fini (&plist);
+    }
 
 qos_err:
     dds_entity_unlock(par);

src/core/ddsc/tests/topic.c

@@ -125,9 +125,12 @@ Test(ddsc_topic_create, non_participants, .init=ddsc_topic_init, .fini=ddsc_topi
 Test(ddsc_topic_create, duplicate, .init=ddsc_topic_init, .fini=ddsc_topic_fini)
 {
     dds_entity_t topic;
-    /* Creating the same topic should fail.  */
+    dds_return_t ret;
+    /* Creating the same topic should succeed.  */
     topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, g_topicRtmDataTypeName, NULL, NULL);
-    cr_assert_eq(dds_err_nr(topic), DDS_RETCODE_PRECONDITION_NOT_MET, "returned %s", dds_err_str(topic));
+    cr_assert_gt(topic, 0, "returned %s", dds_err_str(topic));
+    ret = dds_delete(topic);
+    cr_assert_eq(ret, DDS_RETCODE_OK);
 }
 /*************************************************************************************************/