WIP use BorrowedFd in arguments

Implementation of #592.

This is required for IO safety. Or perhaps `AsFd` generics would be
useful.

This will be a breaking API change, and require Rust 1.65.

Currently `wayland-client` compiles here, but server-side needs the same
changes, and things need to be cleaned up a bit.

wayland-client/examples/simple_window.rs

@@ -1,4 +1,4 @@
-use std::{fs::File, os::unix::prelude::AsRawFd};
+use std::{fs::File, os::unix::prelude::AsFd};
 
 use wayland_client::{
     delegate_noop,
@@ -73,8 +73,7 @@ impl Dispatch<wl_registry::WlRegistry, ()> for State {
 
                     let mut file = tempfile::tempfile().unwrap();
                     draw(&mut file, (init_w, init_h));
-                    let pool =
-                        shm.create_pool(file.as_raw_fd(), (init_w * init_h * 4) as i32, qh, ());
+                    let pool = shm.create_pool(file.as_fd(), (init_w * init_h * 4) as i32, qh, ());
                     let buffer = pool.create_buffer(
                         0,
                         init_w as i32,

wayland-client/src/conn.rs

@@ -199,10 +199,11 @@ impl Connection {
     pub fn send_request<I: Proxy>(
         &self,
         proxy: &I,
-        request: I::Request,
+        request: I::Request<'_>,
         data: Option<Arc<dyn ObjectData>>,
     ) -> Result<ObjectId, InvalidId> {
         let (msg, child_spec) = proxy.write_request(self, request)?;
+        let msg = msg.map_fd(|fd| fd.as_raw_fd());
         self.backend.send_request(msg, data, child_spec)
     }
 

wayland-client/src/lib.rs

@@ -169,12 +169,11 @@
 use std::{
     fmt,
     hash::{Hash, Hasher},
-    os::unix::io::RawFd,
     sync::Arc,
 };
 use wayland_backend::{
     client::{InvalidId, ObjectData, ObjectId, WaylandError, WeakBackend},
-    io_lifetimes::OwnedFd,
+    io_lifetimes::{BorrowedFd, OwnedFd},
     protocol::{Interface, Message},
 };
 
@@ -227,7 +226,7 @@ pub trait Proxy: Clone + std::fmt::Debug + Sized {
     /// The event enum for this interface
     type Event;
     /// The request enum for this interface
-    type Request;
+    type Request<'a>;
 
     /// The interface description
     fn interface() -> &'static Interface;
@@ -278,15 +277,15 @@ pub trait Proxy: Clone + std::fmt::Debug + Sized {
     ///
     /// It is an error to use this function on requests that create objects; use
     /// [Proxy::send_constructor] for such requests.
-    fn send_request(&self, req: Self::Request) -> Result<(), InvalidId>;
+    fn send_request(&self, req: Self::Request<'_>) -> Result<(), InvalidId>;
 
     /// Send a request for this object that creates another object.
     ///
     /// It is an error to use this function on requests that do not create objects; use
     /// [Proxy::send_request] for such requests.
     fn send_constructor<I: Proxy>(
         &self,
-        req: Self::Request,
+        req: Self::Request<'_>,
         data: Arc<dyn ObjectData>,
     ) -> Result<I, InvalidId>;
 
@@ -304,11 +303,11 @@ pub trait Proxy: Clone + std::fmt::Debug + Sized {
     /// **Note:** This method is mostly meant as an implementation detail to be
     /// used by code generated by wayland-scanner.
     #[allow(clippy::type_complexity)]
-    fn write_request(
+    fn write_request<'a>(
         &self,
         conn: &Connection,
-        req: Self::Request,
-    ) -> Result<(Message<ObjectId, RawFd>, Option<(&'static Interface, u32)>), InvalidId>;
+        req: Self::Request<'a>,
+    ) -> Result<(Message<ObjectId, BorrowedFd<'a>>, Option<(&'static Interface, u32)>), InvalidId>;
 
     /// Creates a weak handle to this object
     ///

wayland-cursor/src/lib.rs

@@ -49,7 +49,7 @@ use std::env;
 use std::fs::File;
 use std::io::{Error as IoError, Read, Result as IoResult, Seek, SeekFrom, Write};
 use std::ops::{Deref, Index};
-use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
+use std::os::unix::io::{AsFd, FromRawFd, RawFd};
 use std::sync::Arc;
 use std::time::{SystemTime, UNIX_EPOCH};
 
@@ -145,7 +145,7 @@ impl CursorTheme {
 
         let pool_id = conn.send_request(
             &shm,
-            wl_shm::Request::CreatePool { fd: file.as_raw_fd(), size: INITIAL_POOL_SIZE },
+            wl_shm::Request::CreatePool { fd: file.as_fd(), size: INITIAL_POOL_SIZE },
             Some(Arc::new(IgnoreObjectData)),
         )?;
         let pool = WlShmPool::from_id(conn, pool_id)?;

wayland-scanner/src/client_gen.rs

@@ -21,13 +21,13 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
     let enums = crate::common::generate_enums_for(interface);
     let sinces = crate::common::gen_msg_constants(&interface.requests, &interface.events);
 
-    let requests = crate::common::gen_message_enum(
+    let (requests, requests_is_generic) = crate::common::gen_message_enum(
         &format_ident!("Request"),
         Side::Client,
         false,
         &interface.requests,
     );
-    let events = crate::common::gen_message_enum(
+    let (events, _) = crate::common::gen_message_enum(
         &format_ident!("Event"),
         Side::Client,
         true,
@@ -49,6 +49,12 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
     };
     let doc_attr = to_doc_attr(&docs);
 
+    let request_generic = if requests_is_generic {
+        quote! { 'request }
+    } else {
+        quote! {}
+    };
+
     quote! {
         #mod_doc
         pub mod #mod_name {
@@ -103,7 +109,7 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
             }
 
             impl super::wayland_client::Proxy for #iface_name {
-                type Request = Request;
+                type Request<'request> = Request<#request_generic>;
                 type Event = Event;
 
                 #[inline]
@@ -134,14 +140,14 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
                     &self.backend
                 }
 
-                fn send_request(&self, req: Self::Request) -> Result<(), InvalidId> {
+                fn send_request(&self, req: Self::Request<'_>) -> Result<(), InvalidId> {
                     let conn = Connection::from_backend(self.backend.upgrade().ok_or(InvalidId)?);
                     let id = conn.send_request(self, req, None)?;
                     debug_assert!(id.is_null());
                     Ok(())
                 }
 
-                fn send_constructor<I: Proxy>(&self, req: Self::Request, data: Arc<dyn ObjectData>) -> Result<I, InvalidId> {
+                fn send_constructor<I: Proxy>(&self, req: Self::Request<'_>, data: Arc<dyn ObjectData>) -> Result<I, InvalidId> {
                     let conn = Connection::from_backend(self.backend.upgrade().ok_or(InvalidId)?);
                     let id = conn.send_request(self, req, Some(data))?;
                     Proxy::from_id(&conn, id)
@@ -167,7 +173,7 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
                     #parse_body
                 }
 
-                fn write_request(&self, conn: &Connection, msg: Self::Request) -> Result<(Message<ObjectId, std::os::unix::io::RawFd>, Option<(&'static Interface, u32)>), InvalidId> {
+                fn write_request<'a>(&self, conn: &Connection, msg: Self::Request<'a>) -> Result<(Message<ObjectId, io_lifetimes::BorrowedFd<'a>>, Option<(&'static Interface, u32)>), InvalidId> {
                     #write_body
                 }
             }
@@ -211,7 +217,7 @@ fn gen_methods(interface: &Interface) -> TokenStream {
                     Type::Fixed => quote! { f64 },
                     Type::String => if arg.allow_null { quote!{ Option<String> } } else { quote!{ String } },
                     Type::Array => if arg.allow_null { quote!{ Option<Vec<u8>> } } else { quote!{ Vec<u8> } },
-                    Type::Fd => quote! { ::std::os::unix::io::RawFd },
+                    Type::Fd => quote! { ::std::os::unix::io::BorrowedFd<'_> },
                     Type::Object => {
                         let iface = arg.interface.as_ref().unwrap();
                         let iface_mod = Ident::new(iface, Span::call_site());

wayland-scanner/src/common.rs

@@ -159,30 +159,36 @@ pub(crate) fn gen_message_enum(
     side: Side,
     receiver: bool,
     messages: &[Message],
-) -> TokenStream {
-    let variants = messages.iter().map(|msg| {
-        let mut docs = String::new();
-        if let Some((ref short, ref long)) = msg.description {
-            write!(docs, "{}\n\n{}\n", short, long.trim()).unwrap();
-        }
-        if let Some(Type::Destructor) = msg.typ {
-            write!(
-                docs,
-                "\nThis is a destructor, once {} this object cannot be used any longer.",
-                if receiver { "received" } else { "sent" },
-            )
-            .unwrap()
-        }
-        if msg.since > 1 {
-            write!(docs, "\nOnly available since version {} of the interface", msg.since).unwrap();
-        }
+) -> (TokenStream, bool) {
+    let mut needs_generic = false;
+
+    let variants = messages
+        .iter()
+        .map(|msg| {
+            let mut docs = String::new();
+            if let Some((ref short, ref long)) = msg.description {
+                write!(docs, "{}\n\n{}\n", short, long.trim()).unwrap();
+            }
+            if let Some(Type::Destructor) = msg.typ {
+                write!(
+                    docs,
+                    "\nThis is a destructor, once {} this object cannot be used any longer.",
+                    if receiver { "received" } else { "sent" },
+                )
+                .unwrap()
+            }
+            if msg.since > 1 {
+                write!(docs, "\nOnly available since version {} of the interface", msg.since)
+                    .unwrap();
+            }
 
-        let doc_attr = to_doc_attr(&docs);
-        let msg_name = Ident::new(&snake_to_camel(&msg.name), Span::call_site());
-        let msg_variant_decl = if msg.args.is_empty() {
-            msg_name.into_token_stream()
-        } else {
-            let fields = msg.args.iter().flat_map(|arg| {
+            let doc_attr = to_doc_attr(&docs);
+            let msg_name = Ident::new(&snake_to_camel(&msg.name), Span::call_site());
+            let msg_variant_decl =
+                if msg.args.is_empty() {
+                    msg_name.into_token_stream()
+                } else {
+                    let fields = msg.args.iter().flat_map(|arg| {
                 let field_name =
                     format_ident!("{}{}", if is_keyword(&arg.name) { "_" } else { "" }, arg.name);
                 let field_type_inner = if let Some(ref enu) = arg.enum_ {
@@ -199,7 +205,8 @@ pub(crate) fn gen_message_enum(
                             if receiver {
                                 quote! { io_lifetimes::OwnedFd }
                             } else {
-                                quote! { std::os::unix::io::RawFd }
+                                needs_generic = true;
+                                quote! { io_lifetimes::BorrowedFd<'a> }
                             }
                         }
                         Type::Object => {
@@ -264,18 +271,19 @@ pub(crate) fn gen_message_enum(
                 })
             });
 
+                    quote! {
+                        #msg_name {
+                            #(#fields,)*
+                        }
+                    }
+                };
+
             quote! {
-                #msg_name {
-                    #(#fields,)*
-                }
+                #doc_attr
+                #msg_variant_decl
             }
-        };
-
-        quote! {
-            #doc_attr
-            #msg_variant_decl
-        }
-    });
+        })
+        .collect::<Vec<_>>();
 
     let opcodes = messages.iter().enumerate().map(|(opcode, msg)| {
         let msg_name = Ident::new(&snake_to_camel(&msg.name), Span::call_site());
@@ -291,22 +299,31 @@ pub(crate) fn gen_message_enum(
         }
     });
 
-    quote! {
-        #[derive(Debug)]
-        #[non_exhaustive]
-        pub enum #name {
-            #(#variants,)*
-        }
+    let generic = if needs_generic {
+        quote! { 'a }
+    } else {
+        quote! {}
+    };
 
-        impl #name {
-            #[doc="Get the opcode number of this message"]
-            pub fn opcode(&self) -> u16 {
-                match *self {
-                    #(#opcodes,)*
+    (
+        quote! {
+            #[derive(Debug)]
+            #[non_exhaustive]
+            pub enum #name<#generic> {
+                #(#variants,)*
+            }
+
+            impl<#generic> #name<#generic> {
+                #[doc="Get the opcode number of this message"]
+                pub fn opcode(&self) -> u16 {
+                    match *self {
+                        #(#opcodes,)*
+                    }
                 }
             }
-        }
-    }
+        },
+        needs_generic,
+    )
 }
 
 pub(crate) fn gen_parse_body(interface: &Interface, side: Side) -> TokenStream {

wayland-scanner/src/server_gen.rs

@@ -26,13 +26,13 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
     let enums = crate::common::generate_enums_for(interface);
     let msg_constants = crate::common::gen_msg_constants(&interface.requests, &interface.events);
 
-    let requests = crate::common::gen_message_enum(
+    let (requests, _) = crate::common::gen_message_enum(
         &format_ident!("Request"),
         Side::Server,
         true,
         &interface.requests,
     );
-    let events = crate::common::gen_message_enum(
+    let (events, events_is_generic) = crate::common::gen_message_enum(
         &format_ident!("Event"),
         Side::Server,
         false,
@@ -54,6 +54,12 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
     };
     let doc_attr = to_doc_attr(&docs);
 
+    let event_generic = if events_is_generic {
+        quote! { 'event }
+    } else {
+        quote! {}
+    };
+
     quote! {
         #mod_doc
         pub mod #mod_name {
@@ -109,7 +115,7 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
 
             impl super::wayland_server::Resource for #iface_name {
                 type Request = Request;
-                type Event = Event;
+                type Event<'event> = Event<#event_generic>;
 
                 #[inline]
                 fn interface() -> &'static Interface{
@@ -150,7 +156,7 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
                     Ok(#iface_name { id, data, version, handle: conn.backend_handle().downgrade() })
                 }
 
-                fn send_event(&self, evt: Self::Event) -> Result<(), InvalidId> {
+                fn send_event(&self, evt: Self::Event<'_>) -> Result<(), InvalidId> {
                     let handle = DisplayHandle::from(self.handle.upgrade().ok_or(InvalidId)?);
                     handle.send_event(self, evt)
                 }
@@ -159,7 +165,7 @@ fn generate_objects_for(interface: &Interface) -> TokenStream {
                     #parse_body
                 }
 
-                fn write_event(&self, conn: &DisplayHandle, msg: Self::Event) -> Result<Message<ObjectId, std::os::unix::io::RawFd>, InvalidId> {
+                fn write_event<'a>(&self, conn: &DisplayHandle, msg: Self::Event<'a>) -> Result<Message<ObjectId, std::os::unix::io::BorrowedFd<'a>>, InvalidId> {
                     #write_body
                 }
 
@@ -213,7 +219,7 @@ fn gen_methods(interface: &Interface) -> TokenStream {
                                 quote! { Vec<u8> }
                             }
                         }
-                        Type::Fd => quote! { ::std::os::unix::io::RawFd },
+                        Type::Fd => quote! { ::std::os::unix::io::BorrowedFd<'_> },
                         Type::Object | Type::NewId => {
                             let iface = arg.interface.as_ref().unwrap();
                             let iface_mod = Ident::new(iface, Span::call_site());