generate panic messages only if explicitly asked (#569)

* generate panic messages only if explicitly asked

* doc comments restored

build-resources/opaque-types/Cargo.toml

@@ -8,6 +8,7 @@ edition = "2021"
 [features]
 shared-memory = ["zenoh/shared-memory", "dep:zenoh-ext", "zenoh-ext/shared-memory", "zenoh-protocol/shared-memory"]
 unstable = ["zenoh/unstable", "zenoh-ext/unstable", "dep:zenoh-ext"]
+panic = [] # The whole purpose of this project is to generate set of compilation panic messages with calculated structure sizes. To do it the "panic" feature should be set. By default we just want to check if build is successful.
 default = ["zenoh/default"]
 
 [dependencies]

build-resources/opaque-types/src/lib.rs

@@ -1,15 +1,14 @@
-#[cfg(all(feature = "shared-memory", feature = "unstable"))]
+#![allow(unused_doc_comments)]
 use core::ffi::c_void;
 use std::{
-    collections::HashMap,
     sync::{Arc, Condvar, Mutex, MutexGuard},
     thread::JoinHandle,
 };
 
 use zenoh::{
     bytes::{Encoding, ZBytes, ZBytesIterator, ZBytesReader, ZBytesWriter},
     config::Config,
-    handlers::{DefaultHandler, RingChannelHandler},
+    handlers::RingChannelHandler,
     key_expr::KeyExpr,
     pubsub::{Publisher, Subscriber},
     query::{Query, Queryable, Reply, ReplyError},
@@ -44,6 +43,7 @@ macro_rules! get_opaque_type_data {
             const SIZE: usize = std::mem::size_of::<$src_type>();
             const INFO_MESSAGE: &str =
                 concatcp!("type: ", DST_NAME, ", align: ", ALIGN, ", size: ", SIZE);
+            #[cfg(feature = "panic")]
             panic!("{}", INFO_MESSAGE);
         };
     };
@@ -56,9 +56,14 @@ get_opaque_type_data!(ZBytes, z_owned_bytes_t);
 /// A loaned serialized Zenoh data.
 get_opaque_type_data!(ZBytes, z_loaned_bytes_t);
 
-type CSlice = (usize, usize, usize, usize);
+pub struct CSlice {
+    _data: *const u8,
+    _len: usize,
+    _drop: Option<extern "C" fn(data: *mut c_void, context: *mut c_void)>,
+    _context: *mut c_void,
+}
+
 
-/// A contiguous owned sequence of bytes allocated by Zenoh.
 get_opaque_type_data!(CSlice, z_owned_slice_t);
 /// A contiguous sequence of bytes owned by some other entity.
 get_opaque_type_data!(CSlice, z_view_slice_t);

build.rs

@@ -104,7 +104,7 @@ fn produce_opaque_types_data() -> PathBuf {
     let stdio = Stdio::from(out_file);
 
     #[allow(unused_mut)]
-    let mut feature_args: Vec<&str> = vec![];
+    let mut feature_args: Vec<&str> = vec!["-F", "panic"]; // enable output structure sizes in panic messages during build
     for (rust_feature, _c_feature) in RUST_TO_C_FEATURES.entries() {
         if test_feature(rust_feature) {
             feature_args.push("-F");