add FileDescriptor::set_non_blocking

filedescriptor/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "filedescriptor"
-version = "0.6.0"
+version = "0.7.0"
 authors = ["Wez Furlong"]
 edition = "2018"
 repository = "https://github.com/wez/wzsh"

filedescriptor/src/lib.rs

@@ -247,6 +247,16 @@ impl FileDescriptor {
     pub fn as_stdio(&self) -> anyhow::Result<std::process::Stdio> {
         self.as_stdio_impl()
     }
+
+    /// Attempt to change the non-blocking IO mode of the file descriptor.
+    /// Not all kinds of file descriptor can be placed in non-blocking mode
+    /// on all systems, and some file descriptors will claim to be in
+    /// non-blocking mode but it will have no effect.
+    /// File descriptors based on sockets are the most portable type
+    /// that can be successfully made non-blocking.
+    pub fn set_non_blocking(&mut self, non_blocking: bool) -> anyhow::Result<()> {
+        self.set_non_blocking_impl(non_blocking)
+    }
 }
 
 /// Represents the readable and writable ends of a pair of descriptors

filedescriptor/src/unix.rs

@@ -204,6 +204,19 @@ impl FileDescriptor {
         let stdio = unsafe { std::process::Stdio::from_raw_fd(fd) };
         Ok(stdio)
     }
+
+    #[inline]
+    pub(crate) fn set_non_blocking_impl(&mut self, non_blocking: bool) -> anyhow::Result<()> {
+        let on = if non_blocking { 1 } else { 0 };
+        let res = unsafe { libc::ioctl(self.handle.as_raw_file_descriptor(), libc::FIONBIO, &on) };
+        if res != 0 {
+            bail!(
+                "failed to change non-blocking mode: {:?}",
+                std::io::Error::last_os_error()
+            );
+        }
+        Ok(())
+    }
 }
 
 impl Pipe {

filedescriptor/src/windows.rs

@@ -19,8 +19,9 @@ use winapi::um::processthreadsapi::*;
 use winapi::um::winbase::{FILE_TYPE_CHAR, FILE_TYPE_DISK, FILE_TYPE_PIPE};
 use winapi::um::winnt::HANDLE;
 use winapi::um::winsock2::{
-    accept, bind, closesocket, connect, getsockname, htonl, listen, WSAPoll, WSASocketW,
-    WSAStartup, INVALID_SOCKET, SOCKET, SOCK_STREAM, WSADATA, WSA_FLAG_NO_HANDLE_INHERIT,
+    accept, bind, closesocket, connect, getsockname, htonl, ioctlsocket, listen, WSAPoll,
+    WSASocketW, WSAStartup, INVALID_SOCKET, SOCKET, SOCK_STREAM, WSADATA,
+    WSA_FLAG_NO_HANDLE_INHERIT,
 };
 pub use winapi::um::winsock2::{POLLERR, POLLHUP, POLLIN, POLLOUT, WSAPOLLFD as pollfd};
 
@@ -88,14 +89,15 @@ impl<T: FromRawSocket> FromRawSocketDescriptor for T {
 unsafe impl Send for OwnedHandle {}
 
 impl OwnedHandle {
-    fn probe_handle_type_if_unknown(handle: HANDLE, handle_type: HandleType) -> HandleType {
+    fn probe_handle_type_if_unknown(handle: RawHandle, handle_type: HandleType) -> HandleType {
         match handle_type {
             HandleType::Unknown => Self::probe_handle_type(handle),
             t => t,
         }
     }
 
-    pub(crate) fn probe_handle_type(handle: HANDLE) -> HandleType {
+    pub(crate) fn probe_handle_type(handle: RawHandle) -> HandleType {
+        let handle = handle as HANDLE;
         match unsafe { GetFileType(handle) } {
             FILE_TYPE_CHAR => HandleType::Char,
             FILE_TYPE_DISK => HandleType::Disk,
@@ -212,6 +214,29 @@ impl FileDescriptor {
         let stdio = unsafe { std::process::Stdio::from_raw_handle(handle) };
         Ok(stdio)
     }
+
+    #[inline]
+    pub(crate) fn set_non_blocking_impl(&mut self, non_blocking: bool) -> anyhow::Result<()> {
+        if !self.handle.is_socket_handle() {
+            bail!("only socket descriptors can change their non-blocking mode on windows");
+        }
+
+        let mut on = if non_blocking { 1 } else { 0 };
+        let res = unsafe {
+            ioctlsocket(
+                self.as_raw_socket() as SOCKET,
+                winapi::um::winsock2::FIONBIO,
+                &mut on,
+            )
+        };
+        if res != 0 {
+            bail!(
+                "failed to change non-blocking mode: {:?}",
+                std::io::Error::last_os_error()
+            );
+        }
+        Ok(())
+    }
 }
 
 impl IntoRawHandle for FileDescriptor {