Implement I/O-safe traits on types

.github/workflows/ci.yml

@@ -108,6 +108,21 @@ jobs:
       with:
         command:  check
         args: --all --features tokio02
+
+  check_io_safety_feature:
+    name: Check io_safety feature
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+    steps:
+    - uses: actions/checkout@v3
+    - name: check io_safety
+      uses: actions-rs/cargo@v1
+      with:
+        command:  check
+        args: --all --features io_safety
+
 
   cross:
     name: Cross compile

Cargo.toml

@@ -58,6 +58,7 @@ alloc = [
 tokio1 = ["async-global-executor/tokio"]
 tokio02 = ["async-global-executor/tokio02"]
 tokio03 = ["async-global-executor/tokio03"]
+io_safety = []
 
 [dependencies]
 async-attributes = { version = "1.1.1", optional = true }

src/fs/file.rs

@@ -15,6 +15,8 @@ use crate::prelude::*;
 use crate::task::{spawn_blocking, Context, Poll, Waker};
 use crate::utils::Context as _;
 
+const ARC_TRY_UNWRAP_EXPECT: &str = "cannot acquire ownership of the file handle after drop";
+
 /// An open file on the filesystem.
 ///
 /// Depending on what options the file was opened with, this type can be used for reading and/or
@@ -415,6 +417,15 @@ impl From<std::fs::File> for File {
 cfg_unix! {
     use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
 
+    impl File {
+        fn into_std_file(self) -> std::fs::File {
+            let file = self.file.clone();
+            drop(self);
+            Arc::try_unwrap(file)
+                .expect(ARC_TRY_UNWRAP_EXPECT)
+        }
+    }
+
     impl AsRawFd for File {
         fn as_raw_fd(&self) -> RawFd {
             self.file.as_raw_fd()
@@ -429,11 +440,29 @@ cfg_unix! {
 
     impl IntoRawFd for File {
         fn into_raw_fd(self) -> RawFd {
-            let file = self.file.clone();
-            drop(self);
-            Arc::try_unwrap(file)
-                .expect("cannot acquire ownership of the file handle after drop")
-                .into_raw_fd()
+            self.into_std_file().into_raw_fd()
+        }
+    }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
+
+        impl AsFd for File {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                self.file.as_fd()
+            }
+        }
+
+        impl From<OwnedFd> for File {
+            fn from(fd: OwnedFd) -> Self {
+                std::fs::File::from(fd).into()
+            }
+        }
+
+        impl From<File> for OwnedFd {
+            fn from(val: File) -> OwnedFd {
+                self.into_std_file().into()
+            }
         }
     }
 }
@@ -458,10 +487,36 @@ cfg_windows! {
             let file = self.file.clone();
             drop(self);
             Arc::try_unwrap(file)
-                .expect("cannot acquire ownership of the file handle after drop")
+                .expect(ARC_TRY_UNWRAP_EXPECT)
                 .into_raw_handle()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::windows::io::{AsHandle, BorrowedHandle, OwnedHandle};
+
+        impl AsHandle for File {
+            fn as_handle(&self) -> BorrowedHandle<'_> {
+                self.file.as_handle()
+            }
+        }
+
+        impl From<OwnedHandle> for File {
+            fn from(handle: OwnedHandle) -> Self {
+                std::fs::File::from(handle).into()
+            }
+        }
+
+        impl From<File> for OwnedHandle {
+            fn from(val: File) -> OwnedHandle {
+                let file = val.file.clone();
+                drop(val);
+                Arc::try_unwrap(file)
+                    .expect(ARC_TRY_UNWRAP_EXPECT)
+                    .into()
+            }
+        }
+    }
 }
 
 /// An async mutex with non-borrowing lock guards.

src/io/stderr.rs

@@ -180,6 +180,16 @@ cfg_unix! {
             std::io::stderr().as_raw_fd()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd};
+
+        impl AsFd for Stderr {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                std::io::stderr().as_fd()
+            }
+        }
+    }
 }
 
 cfg_windows! {
@@ -190,4 +200,14 @@ cfg_windows! {
             std::io::stderr().as_raw_handle()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsHandle, BorrowedHandle};
+
+        impl AsHandle for Stderr {
+            fn as_handle(&self) -> BorrowedHandle<'_> {
+                std::io::stderr().as_handle()
+            }
+        }
+    }
 }

src/io/stdin.rs

@@ -206,6 +206,16 @@ cfg_unix! {
             std::io::stdin().as_raw_fd()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd};
+
+        impl AsFd for Stderr {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                std::io::stdin().as_fd()
+            }
+        }
+    }
 }
 
 cfg_windows! {
@@ -216,4 +226,14 @@ cfg_windows! {
             std::io::stdin().as_raw_handle()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd};
+
+        impl AsFd for Stdin {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                std::io::stdin().as_fd()
+            }
+        }
+    }
 }

src/io/stdout.rs

@@ -180,6 +180,16 @@ cfg_unix! {
             std::io::stdout().as_raw_fd()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd};
+
+        impl AsFd for Stdout {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                std::io::stdout().as_fd()
+            }
+        }
+    }
 }
 
 cfg_windows! {
@@ -190,4 +200,14 @@ cfg_windows! {
             std::io::stdout().as_raw_handle()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsHandle, BorrowedHandle};
+
+        impl AsHandle for Stdout {
+            fn as_handle(&self) -> BorrowedHandle<'_> {
+                std::io::stdout().as_handle()
+            }
+        }
+    }
 }

src/net/tcp/listener.rs

@@ -282,6 +282,28 @@ cfg_unix! {
             self.watcher.into_inner().unwrap().into_raw_fd()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
+
+        impl AsFd for TcpListener {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                self.watcher.get_ref().as_fd()
+            }
+        }
+
+        impl From<OwnedFd> for TcpListener {
+            fn from(fd: OwnedFd) -> TcpListener {
+                std::net::TcpListener::from(fd).into()
+            }
+        }
+
+        impl From<TcpListener> for OwnedFd {
+            fn from(listener: TcpListener) -> OwnedFd {
+                listener.watcher.into_inner().unwrap().into()
+            }
+        }
+    }
 }
 
 cfg_windows! {
@@ -306,4 +328,26 @@ cfg_windows! {
             self.watcher.into_inner().unwrap().into_raw_socket()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::windows::io::{AsSocket, BorrowedSocket, OwnedSocket};
+
+        impl AsSocket for TcpListener {
+            fn as_socket(&self) -> BorrowedSocket<'_> {
+                self.watcher.get_ref().as_socket()
+            }
+        }
+
+        impl From<OwnedSocket> for TcpListener {
+            fn from(fd: OwnedSocket) -> TcpListener {
+                std::net::TcpListener::from(fd).into()
+            }
+        }
+
+        impl From<TcpListener> for OwnedSocket {
+            fn from(listener: TcpListener) -> OwnedSocket {
+                listener.watcher.into_inner().unwrap().into()
+            }
+        }
+    }
 }

src/net/tcp/stream.rs

@@ -416,6 +416,28 @@ cfg_unix! {
             self.as_raw_fd()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
+
+        impl AsFd for TcpStream {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                self.watcher.get_ref().as_fd()
+            }
+        }
+
+        impl From<OwnedFd> for TcpStream {
+            fn from(fd: OwnedFd) -> TcpStream {
+                std::net::TcpStream::from(fd).into()
+            }
+        }
+
+        impl From<TcpStream> for OwnedFd {
+            fn from(stream: TcpStream) -> OwnedFd {
+                stream.watcher.into_inner().unwrap().into()
+            }
+        }
+    }
 }
 
 cfg_windows! {
@@ -443,4 +465,26 @@ cfg_windows! {
             self.as_raw_socket()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::windows::io::{AsSocket, BorrowedSocket, OwnedSocket};
+
+        impl AsSocket for TcpStream {
+            fn as_socket(&self) -> BorrowedSocket<'_> {
+                self.watcher.get_ref().as_socket()
+            }
+        }
+
+        impl From<OwnedSocket> for TcpStream {
+            fn from(fd: OwnedSocket) -> TcpStream {
+                std::net::TcpListener::from(fd).into()
+            }
+        }
+
+        impl From<TcpStream> for OwnedSocket {
+            fn from(stream: TcpStream) -> OwnedSocket {
+                stream.watcher.into_inner().unwrap().into()
+            }
+        }
+    }
 }

src/net/udp/mod.rs

@@ -562,6 +562,28 @@ cfg_unix! {
             self.watcher.into_inner().unwrap().into_raw_fd()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
+
+        impl AsFd for UdpSocket {
+            fn as_fd(&self) -> BorrowedFd<'_> {
+                self.watcher.get_ref().as_fd()
+            }
+        }
+
+        impl From<OwnedFd> for UdpSocket {
+            fn from(fd: OwnedFd) -> UdpSocket {
+                std::net::TcpStream::from(fd).into()
+            }
+        }
+
+        impl From<UdpSocket> for OwnedFd {
+            fn from(stream: UdpSocket) -> OwnedFd {
+                stream.watcher.into_inner().unwrap().into()
+            }
+        }
+    }
 }
 
 cfg_windows! {
@@ -586,4 +608,26 @@ cfg_windows! {
             self.watcher.into_inner().unwrap().into_raw_socket()
         }
     }
+
+    cfg_io_safety! {
+        use crate::os::windows::io::{AsSocket, BorrowedSocket, OwnedSocket};
+
+        impl AsSocket for UdpSocket {
+            fn as_socket(&self) -> BorrowedSocket<'_> {
+                self.watcher.get_ref().as_socket()
+            }
+        }
+
+        impl From<OwnedSocket> for UdpSocket {
+            fn from(fd: OwnedSocket) -> UdpSocket {
+                std::net::TcpListener::from(fd).into()
+            }
+        }
+
+        impl From<UdpSocket> for OwnedSocket {
+            fn from(stream: UdpSocket) -> OwnedSocket {
+                stream.watcher.into_inner().unwrap().into()
+            }
+        }
+    }
 }