Add a dds_readcdr analogous to dds_takecdr

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

src/core/ddsc/include/dds/dds.h

@@ -2756,6 +2756,53 @@ dds_take_mask_wl(
   uint32_t maxs,
   uint32_t mask);
 
+#define DDS_HAS_READCDR 1
+/**
+ * @brief Access the collection of serialized data values (of same type) and
+ *        sample info from the data reader, readcondition or querycondition.
+ *
+ * This call accesses the serialized data from the data reader, readcondition or
+ * querycondition and makes it available to the application. The serialized data
+ * is made available through \ref ddsi_serdata structures. Returned samples are
+ * marked as READ.
+ *
+ * Return value provides information about the number of samples read, which will
+ * be <= maxs. Based on the count, the buffer will contain serialized data to be
+ * read only when valid_data bit in sample info structure is set.
+ * The buffer required for data values, could be allocated explicitly or can
+ * use the memory from data reader to prevent copy. In the latter case, buffer and
+ * sample_info should be returned back, once it is no longer using the data.
+ *
+ * @param[in]  reader_or_condition Reader, readcondition or querycondition entity.
+ * @param[out] buf An array of pointers to \ref ddsi_serdata structures that contain
+ *                 the serialized data. The pointers can be NULL.
+ * @param[in]  maxs Maximum number of samples to read.
+ * @param[out] si Pointer to an array of \ref dds_sample_info_t returned for each data value.
+ * @param[in]  mask Filter the data based on dds_sample_state_t|dds_view_state_t|dds_instance_state_t.
+ *
+ * @returns A dds_return_t with the number of samples read or an error code.
+ *
+ * @retval >=0
+ *             Number of samples read.
+ * @retval DDS_RETCODE_ERROR
+ *             An internal error has occurred.
+ * @retval DDS_RETCODE_BAD_PARAMETER
+ *             One of the given arguments is not valid.
+ * @retval DDS_RETCODE_ILLEGAL_OPERATION
+ *             The operation is invoked on an inappropriate object.
+ * @retval DDS_RETCODE_ALREADY_DELETED
+ *             The entity has already been deleted.
+ * @retval DDS_RETCODE_PRECONDITION_NOT_MET
+ *             The precondition for this operation is not met.
+ */
+DDS_EXPORT dds_return_t
+dds_readcdr(
+  dds_entity_t reader_or_condition,
+  struct ddsi_serdata **buf,
+  uint32_t maxs,
+  dds_sample_info_t *si,
+  uint32_t mask);
+
 /**
  * @brief Access the collection of serialized data values (of same type) and
  *        sample info from the data reader, readcondition or querycondition.

src/core/ddsc/include/dds/ddsc/dds_rhc.h

@@ -41,6 +41,7 @@ struct dds_rhc_ops {
   struct ddsi_rhc_ops rhc_ops;
   dds_rhc_read_take_t read;
   dds_rhc_read_take_t take;
+  dds_rhc_read_take_cdr_t readcdr;
   dds_rhc_read_take_cdr_t takecdr;
   dds_rhc_add_readcondition_t add_readcondition;
   dds_rhc_remove_readcondition_t remove_readcondition;
@@ -81,6 +82,9 @@ DDS_EXPORT inline int32_t dds_rhc_read (struct dds_rhc *rhc, bool lock, void **v
 DDS_EXPORT inline int32_t dds_rhc_take (struct dds_rhc *rhc, bool lock, void **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t mask, dds_instance_handle_t handle, struct dds_readcond *cond) {
   return rhc->common.ops->take (rhc, lock, values, info_seq, max_samples, mask, handle, cond);
 }
+DDS_EXPORT inline int32_t dds_rhc_readcdr (struct dds_rhc *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle) {
+  return rhc->common.ops->readcdr (rhc, lock, values, info_seq, max_samples, sample_states, view_states, instance_states, handle);
+}
 DDS_EXPORT inline int32_t dds_rhc_takecdr (struct dds_rhc *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle) {
   return rhc->common.ops->takecdr (rhc, lock, values, info_seq, max_samples, sample_states, view_states, instance_states, handle);
 }

src/core/ddsc/src/dds_read.c

@@ -171,7 +171,11 @@ static dds_return_t dds_readcdr_impl (bool take, dds_entity_t reader_or_conditio
   assert (dds_entity_kind (rd->m_entity.m_parent) == DDS_KIND_SUBSCRIBER);
   dds_entity_status_reset (rd->m_entity.m_parent, DDS_DATA_ON_READERS_STATUS);
 
-  ret = dds_rhc_takecdr (rd->m_rhc, lock, buf, si, maxs, mask & DDS_ANY_SAMPLE_STATE, mask & DDS_ANY_VIEW_STATE, mask & DDS_ANY_INSTANCE_STATE, hand);
+  if (take)
+    ret = dds_rhc_takecdr (rd->m_rhc, lock, buf, si, maxs, mask & DDS_ANY_SAMPLE_STATE, mask & DDS_ANY_VIEW_STATE, mask & DDS_ANY_INSTANCE_STATE, hand);
+  else
+    ret = dds_rhc_readcdr (rd->m_rhc, lock, buf, si, maxs, mask & DDS_ANY_SAMPLE_STATE, mask & DDS_ANY_VIEW_STATE, mask & DDS_ANY_INSTANCE_STATE, hand);
+
   dds_entity_unpin (entity);
   thread_state_asleep (ts1);
   return ret;
@@ -225,6 +229,18 @@ dds_return_t dds_read_mask_wl (dds_entity_t rd_or_cnd, void **buf, dds_sample_in
   return dds_read_impl (false, rd_or_cnd, buf, maxs, maxs, si, mask, DDS_HANDLE_NIL, lock, false);
 }
 
+dds_return_t dds_readcdr (dds_entity_t rd_or_cnd, struct ddsi_serdata **buf, uint32_t maxs, dds_sample_info_t *si, uint32_t mask)
+{
+  bool lock = true;
+  if (maxs == DDS_READ_WITHOUT_LOCK)
+  {
+    lock = false;
+    /* FIXME: Fix the interface. */
+    maxs = 100;
+  }
+  return dds_readcdr_impl (false, rd_or_cnd, buf, maxs, si, mask, DDS_HANDLE_NIL, lock);
+}
+
 dds_return_t dds_read_instance (dds_entity_t rd_or_cnd, void **buf, dds_sample_info_t *si, size_t bufsz, uint32_t maxs, dds_instance_handle_t handle)
 {
   bool lock = true;

src/core/ddsc/src/dds_rhc.c

@@ -22,6 +22,7 @@ extern inline void dds_rhc_set_qos (struct dds_rhc *rhc, const struct dds_qos *q
 extern inline void dds_rhc_free (struct dds_rhc *rhc);
 extern inline int dds_rhc_read (struct dds_rhc *rhc, bool lock, void **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t mask, dds_instance_handle_t handle, struct dds_readcond *cond);
 extern inline int dds_rhc_take (struct dds_rhc *rhc, bool lock, void **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t mask, dds_instance_handle_t handle, struct dds_readcond *cond);
+extern inline int dds_rhc_readcdr (struct dds_rhc *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle);
 extern inline int dds_rhc_takecdr (struct dds_rhc *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle);
 extern inline bool dds_rhc_add_readcondition (struct dds_rhc *rhc, struct dds_readcond *cond);
 extern inline void dds_rhc_remove_readcondition (struct dds_rhc *rhc, struct dds_readcond *cond);

src/core/ddsc/src/dds_rhc_default.c

@@ -370,6 +370,7 @@ static void dds_rhc_default_relinquish_ownership (struct dds_rhc_default * __res
 static void dds_rhc_default_set_qos (struct dds_rhc_default *rhc, const struct dds_qos *qos);
 static int32_t dds_rhc_default_read (struct dds_rhc_default *rhc, bool lock, void **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t mask, dds_instance_handle_t handle, dds_readcond *cond);
 static int32_t dds_rhc_default_take (struct dds_rhc_default *rhc, bool lock, void **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t mask, dds_instance_handle_t handle, dds_readcond *cond);
+static int32_t dds_rhc_default_readcdr (struct dds_rhc_default *rhc, bool lock, struct ddsi_serdata ** values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle);
 static int32_t dds_rhc_default_takecdr (struct dds_rhc_default *rhc, bool lock, struct ddsi_serdata ** values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle);
 static bool dds_rhc_default_add_readcondition (struct dds_rhc_default *rhc, dds_readcond *cond);
 static void dds_rhc_default_remove_readcondition (struct dds_rhc_default *rhc, dds_readcond *cond);
@@ -396,6 +397,9 @@ static int32_t dds_rhc_default_read_wrap (struct dds_rhc *rhc, bool lock, void *
 static int32_t dds_rhc_default_take_wrap (struct dds_rhc *rhc, bool lock, void **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t mask, dds_instance_handle_t handle, dds_readcond *cond) {
   return dds_rhc_default_take ((struct dds_rhc_default *) rhc, lock, values, info_seq, max_samples, mask, handle, cond);
 }
+static int32_t dds_rhc_default_readcdr_wrap (struct dds_rhc *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle) {
+  return dds_rhc_default_readcdr ((struct dds_rhc_default *) rhc, lock, values, info_seq, max_samples, sample_states, view_states, instance_states, handle);
+}
 static int32_t dds_rhc_default_takecdr_wrap (struct dds_rhc *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle) {
   return dds_rhc_default_takecdr ((struct dds_rhc_default *) rhc, lock, values, info_seq, max_samples, sample_states, view_states, instance_states, handle);
 }
@@ -425,6 +429,7 @@ static const struct dds_rhc_ops dds_rhc_default_ops = {
   },
   .read = dds_rhc_default_read_wrap,
   .take = dds_rhc_default_take_wrap,
+  .readcdr = dds_rhc_default_readcdr_wrap,
   .takecdr = dds_rhc_default_takecdr_wrap,
   .add_readcondition = dds_rhc_default_add_readcondition_wrap,
   .remove_readcondition = dds_rhc_default_remove_readcondition_wrap,
@@ -2331,6 +2336,13 @@ static int32_t dds_rhc_take_w_qminv (struct dds_rhc_default *rhc, bool lock, voi
   return take_w_qminv (rhc, lock, values, info_seq, (int32_t) max_samples, qminv, handle, cond, read_take_to_sample, read_take_to_invsample);
 }
 
+static int32_t dds_rhc_readcdr_w_qminv (struct dds_rhc_default *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t qminv, dds_instance_handle_t handle, dds_readcond *cond)
+{
+  DDSRT_STATIC_ASSERT (sizeof (void *) == sizeof (struct ddsi_serdata *));
+  assert (max_samples <= INT32_MAX);
+  return read_w_qminv (rhc, lock, (void **) values, info_seq, (int32_t) max_samples, qminv, handle, cond, read_take_to_sample_ref, read_take_to_invsample_ref);
+}
+
 static int32_t dds_rhc_takecdr_w_qminv (struct dds_rhc_default *rhc, bool lock, struct ddsi_serdata **values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t qminv, dds_instance_handle_t handle, dds_readcond *cond)
 {
   DDSRT_STATIC_ASSERT (sizeof (void *) == sizeof (struct ddsi_serdata *));
@@ -2727,6 +2739,12 @@ static int32_t dds_rhc_default_take (struct dds_rhc_default *rhc, bool lock, voi
   return dds_rhc_take_w_qminv (rhc, lock, values, info_seq, max_samples, qminv, handle, cond);
 }
 
+static int32_t dds_rhc_default_readcdr (struct dds_rhc_default *rhc, bool lock, struct ddsi_serdata ** values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle)
+{
+  uint32_t qminv = qmask_from_dcpsquery (sample_states, view_states, instance_states);
+  return dds_rhc_readcdr_w_qminv (rhc, lock, values, info_seq, max_samples, qminv, handle, NULL);
+}
+
 static int32_t dds_rhc_default_takecdr (struct dds_rhc_default *rhc, bool lock, struct ddsi_serdata ** values, dds_sample_info_t *info_seq, uint32_t max_samples, uint32_t sample_states, uint32_t view_states, uint32_t instance_states, dds_instance_handle_t handle)
 {
   uint32_t qminv = qmask_from_dcpsquery (sample_states, view_states, instance_states);