Fix clippy lint warnings.

Signed-off-by: Andrew Walbran <[email protected]>

grpc-sys/build.rs

@@ -300,7 +300,7 @@ fn build_grpc(cc: &mut cc::Build, library: &str) {
 
 fn figure_systemd_path(build_dir: &str) {
     let path = format!("{build_dir}/CMakeCache.txt");
-    let f = BufReader::new(std::fs::File::open(&path).unwrap());
+    let f = BufReader::new(std::fs::File::open(path).unwrap());
     let mut libdir: Option<String> = None;
     let mut libname: Option<String> = None;
     for l in f.lines() {

interop/src/client.rs

@@ -80,7 +80,7 @@ impl Client {
 
     pub async fn server_streaming(&self) -> grpcio::Result<()> {
         print!("testing server streaming ... ");
-        let sizes = vec![31415, 9, 2653, 58979];
+        let sizes = [31415, 9, 2653, 58979];
         let req = StreamingOutputCallRequest {
             response_parameters: sizes
                 .iter()

src/buf.rs

@@ -262,7 +262,7 @@ impl<'a> From<&'a GrpcSlice> for GrpcByteBuffer {
     /// Create a buffer from the given single slice.
     ///
     /// A buffer, which length is 1, is allocated for the slice.
-    #[allow(clippy::cast_ref_to_mut)]
+    #[allow(invalid_reference_casting)]
     fn from(s: &'a GrpcSlice) -> GrpcByteBuffer {
         unsafe {
             // hack: buffer_create accepts an mutable pointer to indicate it mutate

src/channel.rs

@@ -592,6 +592,11 @@ struct ChannelInner {
     channel: *mut grpc_channel,
 }
 
+// SAFETY: `grpc_channel` is safe to send between threads, and `Environment` is already `Send`.
+unsafe impl Send for ChannelInner {}
+// SAFETY: `grpc_channel` can be used from multiple threads, and `Environment` is already `Sync`.
+unsafe impl Sync for ChannelInner {}
+
 impl ChannelInner {
     // If try_to_connect is true, the channel will try to establish a connection, potentially
     // changing the state.
@@ -622,10 +627,6 @@ pub struct Channel {
     cq: CompletionQueue,
 }
 
-#[allow(clippy::non_send_fields_in_send_ty)]
-unsafe impl Send for Channel {}
-unsafe impl Sync for Channel {}
-
 impl Channel {
     /// Create a new channel. Avoid using this directly and use
     /// [`ChannelBuilder`] to build a [`Channel`] instead.

src/server.rs

@@ -7,6 +7,7 @@ use std::fmt::{self, Debug, Formatter};
 use std::future::Future;
 use std::pin::Pin;
 use std::ptr;
+use std::rc::Rc;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 use std::task::{Context, Poll};
@@ -298,7 +299,7 @@ pub type BoxHandler = Box<dyn CloneableHandler>;
 #[derive(Clone)]
 pub struct RequestCallContext {
     server: Arc<ServerCore>,
-    registry: Arc<UnsafeCell<HashMap<&'static [u8], BoxHandler>>>,
+    registry: Rc<UnsafeCell<HashMap<&'static [u8], BoxHandler>>>,
     checkers: Vec<Box<dyn ServerChecker>>,
 }
 
@@ -420,7 +421,7 @@ impl Server {
                     .collect();
                 let rc = RequestCallContext {
                     server: self.core.clone(),
-                    registry: Arc::new(UnsafeCell::new(registry)),
+                    registry: Rc::new(UnsafeCell::new(registry)),
                     checkers: self.checkers.clone(),
                 };
                 for _ in 0..self.core.slots_per_cq {