From 1b09b308accafcbb4c9e54675bf6e878072d18de Mon Sep 17 00:00:00 2001
From: Pierre Avital <pierre.avital@me.com>
Date: Fri, 8 Mar 2024 11:16:02 +0100
Subject: [PATCH] address pr comments

---
 include/zenoh_commons.h |  9 +--------
 src/commons.rs          | 16 +++++-----------
 src/lib.rs              |  8 ++++++++
 3 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/include/zenoh_commons.h b/include/zenoh_commons.h
index 5e3af4644..e0b405014 100644
--- a/include/zenoh_commons.h
+++ b/include/zenoh_commons.h
@@ -383,14 +383,6 @@ typedef struct z_owned_closure_reply_t {
  * A data sample.
  *
  * A sample is the value associated to a given resource at a given point in time.
- *
- * Members:
- *   z_keyexpr_t keyexpr: The resource key of this data sample.
- *   z_bytes_t payload: The value of this data sample.
- *   z_encoding_t encoding: The encoding of the value of this data sample.
- *   z_sample_kind_t kind: The kind of this data sample (PUT or DELETE).
- *   z_timestamp_t timestamp: The timestamp of this data sample.
- *   z_attachment_t attachment: The attachment of this data sample.
  */
 typedef struct z_sample_t {
   const void *_inner;
@@ -2503,6 +2495,7 @@ ZENOHC_API void zc_sample_drop(struct zc_owned_sample_t *sample);
  * Calling this function using a dropped sample is undefined behaviour.
  */
 ZENOHC_API struct z_sample_t zc_sample_loan(const struct zc_owned_sample_t *sample);
+ZENOHC_API struct zc_owned_sample_t zc_sample_null(void);
 /**
  * Increments the session's reference count, returning a new owning handle.
  */
diff --git a/src/commons.rs b/src/commons.rs
index 555a380be..d23618846 100644
--- a/src/commons.rs
+++ b/src/commons.rs
@@ -156,14 +156,6 @@ pub extern "C" fn z_qos_default() -> z_qos_t {
 /// A data sample.
 ///
 /// A sample is the value associated to a given resource at a given point in time.
-///
-/// Members:
-///   z_keyexpr_t keyexpr: The resource key of this data sample.
-///   z_bytes_t payload: The value of this data sample.
-///   z_encoding_t encoding: The encoding of the value of this data sample.
-///   z_sample_kind_t kind: The kind of this data sample (PUT or DELETE).
-///   z_timestamp_t timestamp: The timestamp of this data sample.
-///   z_attachment_t attachment: The attachment of this data sample.
 #[repr(C)]
 pub struct z_sample_t<'a> {
     _inner: &'a (),
@@ -177,9 +169,6 @@ impl<'a> core::ops::Deref for z_sample_t<'a> {
 
 impl<'a> z_sample_t<'a> {
     pub fn new(sample: &'a Sample) -> Self {
-        if !sample.value.payload.zslices().count() <= 1 {
-            panic!("Attempted to construct z_sample_t from discontiguous buffer, this is definitely a bug in zenoh-c, please report it.")
-        };
         z_sample_t {
             _inner: unsafe { core::mem::transmute(sample) },
         }
@@ -285,6 +274,11 @@ pub extern "C" fn zc_sample_drop(sample: &mut zc_owned_sample_t) {
     core::mem::drop(sample.take());
 }
 
+#[no_mangle]
+pub extern "C" fn zc_sample_null() -> zc_owned_sample_t {
+    None.into()
+}
+
 /// A :c:type:`z_encoding_t` integer `prefix`.
 ///
 ///     - **Z_ENCODING_PREFIX_EMPTY**
diff --git a/src/lib.rs b/src/lib.rs
index 9c01e4aa2..2ff9259c6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -58,6 +58,14 @@ trait GuardedTransmute<D> {
     fn transmute(self) -> D;
 }
 
+/// For internal use only.
+///
+/// This macro is used to establish the equivalence between a Rust type (first parameter) and a C layout (second parameter).
+///
+/// It automatically implements `From`, `Deref` and `DerefMut` to make writing code around these equivalent types.
+///
+/// Because carrying around the proper semantics of lifetimes is hard, this macro fails to produce working code when lifetimes are
+/// present in either parameter. You may then call it with the `noderefs` prefix to avoid the offending implementations being defined.
 #[macro_export]
 macro_rules! impl_guarded_transmute {
     ($src_type:ty, $dst_type:ty) => {