Restore close to socket type

Now that double-close is permitted, we can simplify the types by making
all sockets closable.

This reverts commit ccf1474.

lib_eio/mock/eio_mock.mli

@@ -119,8 +119,8 @@ module Net : sig
   type t = <
     Eio.Net.t;
     on_listen : Eio.Net.listening_socket Handler.t;
-    on_connect : <Eio.Net.stream_socket; Eio.Flow.close> Handler.t;
-    on_datagram_socket : <Eio.Net.datagram_socket; Eio.Flow.close> Handler.t;
+    on_connect : Eio.Net.stream_socket Handler.t;
+    on_datagram_socket : Eio.Net.datagram_socket Handler.t;
     on_getaddrinfo : Eio.Net.Sockaddr.t list Handler.t;
     on_getnameinfo : (string * string) Handler.t;
   >
@@ -133,13 +133,13 @@ module Net : sig
   val make : string -> t
   (** [make label] is a new mock network. *)
 
-  val on_connect : t -> <Eio.Net.stream_socket; Eio.Flow.close; ..> Handler.actions -> unit
+  val on_connect : t -> <Eio.Net.stream_socket; ..> Handler.actions -> unit
   (** [on_connect t actions] configures what to do when a client tries to connect somewhere. *)
 
   val on_listen : t -> #Eio.Net.listening_socket Handler.actions -> unit
   (** [on_listen t actions] configures what to do when a server starts listening for incoming connections. *)
 
-  val on_datagram_socket : t -> <Eio.Net.datagram_socket; Eio.Flow.close; ..> Handler.actions -> unit
+  val on_datagram_socket : t -> <Eio.Net.datagram_socket; ..> Handler.actions -> unit
   (** [on_datagram_socket t actions] configures how to create datagram sockets. *)
 
   val on_getaddrinfo : t -> Eio.Net.Sockaddr.t list Handler.actions -> unit

lib_eio/mock/net.ml

@@ -3,8 +3,8 @@ open Eio.Std
 type t = <
   Eio.Net.t;
   on_listen : Eio.Net.listening_socket Handler.t;
-  on_connect : <Eio.Net.stream_socket; Eio.Flow.close> Handler.t;
-  on_datagram_socket : <Eio.Net.datagram_socket; Eio.Flow.close> Handler.t;
+  on_connect : Eio.Net.stream_socket Handler.t;
+  on_datagram_socket : Eio.Net.datagram_socket Handler.t;
   on_getaddrinfo : Eio.Net.Sockaddr.t list Handler.t;
   on_getnameinfo : (string * string) Handler.t;
 >
@@ -56,15 +56,15 @@ let make label =
   end
 
 let on_connect (t:t) actions =
-  let as_socket x = (x :> <Eio.Net.stream_socket; Eio.Flow.close>) in
+  let as_socket x = (x :> Eio.Net.stream_socket) in
   Handler.seq t#on_connect (List.map (Action.map as_socket) actions)
 
 let on_listen (t:t) actions =
-  let as_socket x = (x :> <Eio.Net.listening_socket; Eio.Flow.close>) in
+  let as_socket x = (x :> Eio.Net.listening_socket) in
   Handler.seq t#on_listen (List.map (Action.map as_socket) actions)
 
 let on_datagram_socket (t:t) actions =
-  let as_socket x = (x :> <Eio.Net.datagram_socket; Eio.Flow.close>) in
+  let as_socket x = (x :> Eio.Net.datagram_socket) in
   Handler.seq t#on_datagram_socket (List.map (Action.map as_socket) actions)
 
 let on_getaddrinfo (t:t) actions = Handler.seq t#on_getaddrinfo actions
@@ -87,7 +87,7 @@ let listening_socket label =
       let socket, addr = Handler.run on_accept in
       Flow.attach_to_switch socket sw;
       traceln "%s: accepted connection from %a" label Eio.Net.Sockaddr.pp addr;
-      (socket :> <Eio.Net.stream_socket; Eio.Flow.close>), addr
+      (socket :> Eio.Net.stream_socket), addr
 
     method close =
       traceln "%s: closed" label

lib_eio/net.ml

@@ -157,7 +157,7 @@ module Sockaddr = struct
       Format.fprintf f "udp:%a:%d" Ipaddr.pp_for_uri addr port
 end
 
-class virtual socket = object (_ : #Generic.t)
+class virtual socket = object (_ : <Generic.t; Generic.close; ..>)
   method probe _ = None
 end
 

lib_eio/net.mli

@@ -102,7 +102,7 @@ end
 
 (** {2 Provider Interfaces} *)
 
-class virtual socket : object
+class virtual socket : object (<Generic.close; ..>)
   inherit Generic.t
 end
 

lib_eio/unix/net.ml

@@ -23,11 +23,11 @@ let sockaddr_of_unix_datagram = function
     let host = Ipaddr.of_unix host in
     `Udp (host, port)
 
-class virtual stream_socket = object (_ : <Resource.t; Eio.Flow.close; ..>)
+class virtual stream_socket = object (_ : <Resource.t; ..>)
   inherit Eio.Net.stream_socket
 end
 
-class virtual datagram_socket = object (_ : <Resource.t; Eio.Flow.close; ..>)
+class virtual datagram_socket = object (_ : <Resource.t; ..>)
   inherit Eio.Net.datagram_socket
 end
 

lib_eio/unix/net.mli

@@ -4,11 +4,11 @@ open Eio.Std
 
     These extend the types in {!Eio.Net} with support for file descriptors. *)
 
-class virtual stream_socket : object (<Resource.t; Eio.Flow.close; ..>)
+class virtual stream_socket : object (<Resource.t; ..>)
   inherit Eio.Net.stream_socket
 end
 
-class virtual datagram_socket : object (<Resource.t; Eio.Flow.close; ..>)
+class virtual datagram_socket : object (<Resource.t; ..>)
   inherit Eio.Net.datagram_socket
 end
 

lib_eio_linux/eio_linux.ml

@@ -187,7 +187,7 @@ let listening_socket fd = object
       | Unix.ADDR_UNIX path         -> `Unix path
       | Unix.ADDR_INET (host, port) -> `Tcp (Eio_unix.Net.Ipaddr.of_unix host, port)
     in
-    let flow = (flow client :> <Eio.Net.stream_socket; Eio.Flow.close>) in
+    let flow = (flow client :> Eio.Net.stream_socket) in
     flow, client_addr
 
   method! probe : type a. a Eio.Generic.ty -> a option = function
@@ -210,7 +210,7 @@ let connect ~sw connect_addr =
   let sock_unix = Unix.socket ~cloexec:true (socket_domain_of connect_addr) Unix.SOCK_STREAM 0 in
   let sock = FD.of_unix ~sw ~seekable:false ~close_unix:true sock_unix in
   Low_level.connect sock addr;
-  (flow sock :> <Eio.Net.stream_socket; Eio.Flow.close>)
+  (flow sock :> Eio.Net.stream_socket)
 
 let net = object
   inherit Eio_unix.Net.t
@@ -269,7 +269,7 @@ let net = object
       Unix.bind sock_unix addr
     | `UdpV4 | `UdpV6 -> ()
     end;
-    (datagram_socket sock :> <Eio.Net.datagram_socket; Eio.Flow.close>)
+    (datagram_socket sock :> Eio.Net.datagram_socket)
 
   method getaddrinfo = Low_level.getaddrinfo
 end

lib_eio_posix/net.ml

@@ -25,7 +25,7 @@ let listening_socket ~hook fd = object
       | Unix.ADDR_UNIX path         -> `Unix path
       | Unix.ADDR_INET (host, port) -> `Tcp (Eio_unix.Net.Ipaddr.of_unix host, port)
     in
-    let flow = (Flow.of_fd client :> <Eio.Net.stream_socket; Eio.Flow.close>) in
+    let flow = (Flow.of_fd client :> Eio.Net.stream_socket) in
     flow, client_addr
 
   method! probe : type a. a Eio.Generic.ty -> a option = function
@@ -118,7 +118,7 @@ let connect ~sw connect_addr =
   let sock = Low_level.socket ~sw (socket_domain_of connect_addr) socket_type 0 in
   try
     Low_level.connect sock addr;
-    (Flow.of_fd sock :> <Eio.Net.stream_socket; Eio.Flow.close>)
+    (Flow.of_fd sock :> Eio.Net.stream_socket)
   with Unix.Unix_error (code, name, arg) -> raise (Err.wrap code name arg)
 
 let create_datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
@@ -135,7 +135,7 @@ let create_datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
         )
     | `UdpV4 | `UdpV6 -> ()
   end;
-  (datagram_socket sock :> <Eio.Net.datagram_socket; Eio.Flow.close>)
+  (datagram_socket sock :> Eio.Net.datagram_socket)
 
 let v = object
   inherit Eio_unix.Net.t

lib_eio_windows/net.ml

@@ -25,7 +25,7 @@ let listening_socket ~hook fd = object
       | Unix.ADDR_UNIX path         -> `Unix path
       | Unix.ADDR_INET (host, port) -> `Tcp (Eio_unix.Net.Ipaddr.of_unix host, port)
     in
-    let flow = (Flow.of_fd client :> <Eio.Net.stream_socket; Eio.Flow.close>) in
+    let flow = (Flow.of_fd client :> Eio.Net.stream_socket) in
     flow, client_addr
 
   method! probe : type a. a Eio.Generic.ty -> a option = function
@@ -123,7 +123,7 @@ let connect ~sw connect_addr =
   let sock = Low_level.socket ~sw (socket_domain_of connect_addr) socket_type 0 in
   try
     Low_level.connect sock addr;
-    (Flow.of_fd sock :> <Eio.Net.stream_socket; Eio.Flow.close>)
+    (Flow.of_fd sock :> Eio.Net.stream_socket)
   with Unix.Unix_error (code, name, arg) -> raise (Err.wrap code name arg)
 
 let create_datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
@@ -140,7 +140,7 @@ let create_datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
         )
     | `UdpV4 | `UdpV6 -> ()
   end;
-  (datagram_socket sock :> <Eio.Net.datagram_socket; Eio.Flow.close>)
+  (datagram_socket sock :> Eio.Net.datagram_socket)
 
 let v = object
   inherit Eio_unix.Net.t

tests/network.md

@@ -249,6 +249,31 @@ Handling one UDP packet using IPv6:
 - : unit = ()
 ```
 
+It's not an error to close the socket before the handler returns:
+
+```ocaml
+# run @@ fun ~net sw ->
+  let addr = `Tcp (Eio.Net.Ipaddr.V4.loopback, 8083) in
+  let server = Eio.Net.listen net ~sw ~reuse_addr:true ~backlog:5 addr in
+  Fiber.both
+    (fun () ->
+        Eio.Net.accept_fork server ~sw ~on_error:raise @@ fun flow _addr ->
+        traceln "Server got connection";
+        Eio.Flow.copy_string "Hi" flow;
+        Eio.Flow.close flow
+    )
+    (fun () ->
+      traceln "Connecting to server...";
+      let flow = Eio.Net.connect ~sw net addr in
+      let msg = Eio.Buf_read.(parse_exn take_all) flow ~max_size:100 in
+      traceln "Client got %S" msg;
+    );;
++Connecting to server...
++Server got connection
++Client got "Hi"
+- : unit = ()
+```
+
 ## Unix interop
 
 Extracting file descriptors from Eio objects: